STEPHENS, Associate Justice.
This is an appeal from a decree of the District Court of the United States for the District of Columbia dismissing, after a hearing on the merits, a bill of complaint filed by the appellants under Rev.Stat. § 4915, as amended, 35 U.S.C.A. § 63. The [237]*237bill sought to require the appellee United States Commissioner of Patents, hereafter referred to as the Commissioner, to issue a patent upon the application of Ralph B. Frazier, Serial No. 605,129, for certain new and useful improvements in food packages. The application will be referred to hereafter as the Frazier application. The application, the rights under which had been assigned to the appellant Carbide and Carbon Chemicals Corporation, was duly prosecuted in the Patent Office, and the primary examiner finally rejected claims 4, 5, 6, 7, 8, 11, 13, 14 and 22. This rejection was affirmed by the Board of Appeals. In the hearing in the trial court the record in the Patent Office was as usual introduced in evidence; and there was also heard testimony by Frazier, Frank R. Stoner, Jr., .and Arthur K. Doolittle, as experts. At the conclusion of the hearing, the trial judge ruled that no invention was disclosed by the application. The sole question in this appeal is as to the correctness of this ruling in respect of the claims mentioned.
From Frazier’s application and the testimony in the trial court, the following appears : The principal obj ect of the claimed invention is “to provide improved composite materials for use particularly in packaging foodstuffs.” Metal foil and metal cans, commonly used in such packaging to prevent desiccation and spoilage, are often corroded by contact with the foodstuff with resultant contamination and deterioration of the foodstuff itself. This occurs, for example, in the packaging of cheese in metal foil and of orange juice and beer in metal cans. The problem in the art was to discover a coating which would render metal packaging material, whether foil or cans, resistant to chemical action by elements •contained in foodstuffs to be packaged, and also render metal foil packaging material impervious to exterior gases, moisture, .grease and oils; it was also essential that the coating in contact with the foodstuff should be free from volatile or soluble constituents which might impart an odor or taste thereto.
Frazier testified that while employed by the Carbide and Carbon Chemicals Corporation upon a fellowship in the Mellon Institute, where his duties comprised working with solvents, experimenting with nitrocellulose lacquers with which the solvents were used, and developing uses for new products such as vinyl resins, an inquiry was received from a European country asking for a coating to protect tinfoil for food packaging. An inquiry had also been received from an American company for a coating for foil to be used in packaging cheese. In this the problem was to prevent corrosion of the foil which gave rise to darkening of the cheese and to gas formation. Knowing that in the nitrocellulose lacquers tough films adhering to metal foils were available, Frazier thought first of the use of such a lacquer. Foil was coated at the laboratory by a spray application, two nitrocellulose lacquers of the best formula which could be developed being used; and one application was made with vinyl resin in it. The nitrocellulose lacquer samples were not successful — they produced an odor; and no more tests were made with them. But the foil coated with vinyl resin showed promise. Similar problems were investigated for can manufacturing companies in respect of coating tin cans for the packaging of vegetables, orange juice and the like. The results of the tests of vinyl resins in metallic food containers showed definitely that the coating would not impart odor or taste to the product and the tests were successful. They were however not entirely as expected; although Frazier had been working for a considerable period of time before this with vinyl resin coating compositions, they turned out in these tests to be better than he had reason to expect.
Frazier stated in his specification that he had:
“ . . . discovered by test that the object of the invention may be attained, and new composite materials may be produced by providing metallic materials used for packaging purposes, particularly for foodstuffs, with a surface or surfaces which contain vinyl resins, that is, resinous products resulting from the polymerization[1] of certain vinyl compounds.
“Vinyl resins suitable for use in forming the materials of my inventions may be formed from vinyl esters by known poly[238]*238merization processes. The polymerization products of inorganic vinyl esters, such as vinyl halides, or those of organic vinyl esters, such as vinyl esters of aliphatic acids may be used. I prefer to use vinyl resins resulting from the conjoint polymerization (by which is meant polymerization of a plurality of compounds while in mutual contact) of two or more vinyl esters. For example, vinyl resins having desirable properties may be prepared by the conjoint polymerization of a vinyl halide and a vinyl ester of an aliphatic acid. Products of the conjoint polymerization of vinyl .chloride and vinyl acetate in proportions ranging from about 10% to 90% by weight of the chloride are particularly desirable. Such resins are substantially water-white and transparent and they are exceptionally resistant to acids, alkalies and salts in the presence of moisture and may be used to form tough, flexible films which adhere well to metals, and which aré odorless and tasteless. In addition, I have found that the characteristics of the preferred vinyl resins are retained to a very great extent when the vinyl resin is modified by the addition of a second resin or gum, a cellulose ester or a high-boiling solvent having plasticizing or softening action on the resin. Due to this property the vinyl resins may be greatly modified to meet specific requirements without materially altering the chemical properties of the resins which are necessary to the materials of this invention.
“The material Of my invention may be prepared by coating the metallic packaging material, at least on the surface thereof which is to be contacted with the packaged product, with a vinyl resin or vinyl resin composition. This may be done conveniently by forming a solution of the resin with or without modifying materials, applying the solution to the metal, and eliminating the solvent.”
The specification gives several examples of proportions which may be used to accomplish the result of the invention. It is explained in the testimony that after the elimination of the solvent the film thus dried may be baked to insure adhesion to the metal or foil.
The claims: Claim 4 is typical of claims 4, 5, and 6, and reads as follows:
“4. A food package comprising a metallic material having at least the surface thereof- which is in contact with the food product to be packaged composed of a composition which contains a substantial proportion of a vinyl resin of the group including polymerization products of vinyl esters and mixtures of vinyl esters.”
The remaining claims are as follows:
“7. A food package which comprises a food product and a metallic packaging material having at least the surface thereof which contacts the packaged product composed of a composition which contains a vinyl resin substantially identical with a product resulting from the conjoint polymerization of vinyl chloride and vinyl acetate in the proportions of about 60% to 90% by weight vinyl chloride.
“8. A food package which comprises a food product and a metallic packaging material having at least the surface thereof which contacts the packaged product composed of a composition which contains a vinyl resin substantially identical with a product Resulting from the conjoint polymerization of vinyl chloride and vinyl acetate in the proportions of less than about 65% by weight vinyl chloride, together with nitrocellulose.
“11. Process of protectively packaging food products which comprises enclosing the food product in a metallic packaging material which has at least the surface thereof which is in contact with said food product composed of a composition which contains a substantial proportion of a vinyl resin of the group including polymerization products of vinyl esters and mixtures of vinyl esters.
“13. As a new product, a package comprising cheese enclosed by and substantially sealed in a wrapping consisting essentially of metal foil which has at least the surface thereof in contact with said cheese composed of a composition which contains a substantial proportion of vinyl resin of the group including polymerization products of vinyl esters and mixtures of vinyl esters.
“14. As a new product, a package comprising cheese enclosed by and substantially sealed in a wrapping consisting essentially of metal foil which has at least the surface thereof in contact with said cheese composed of a composition which contains a vinyl resin substantially identical with a product resulting from the conjoint polymerization of vinyl acetate and vinyl chloride in the proportions of about 60% to 90% by weight vinyl chloride.
“22. Process of protectively packaging cheese, which comprises pouring heated [239]*239molten cheese into molds lined with a metallic packaging material which has at least the surface thereof which is in contact with the said cheese composed of a composition containing a substantial proportion of a vinyl resin of the group including polymerization products of vinyl esters and mixtures of vinyl esters, together with a plasticizer, thereby slightly softening the vinyl resin and causing lapped portions of the said surface of the packaging material to be effectively sealed.”
According to the testimony, Frazier’s vinyl resin coating has proved to be of great utility and has gained great commercial success. In respect of utility, it was testified that: Work had been done on the problem of discovering a satisfactory material for lining metal cans and metal foil as food containers for nine or ten years prior to the work of Frazier, and nothing had been discovered suitable for either foil for food such as cheese or containers for beverages. Apparently every known coating material had been tried for use on tin foil before vinyl resins were used, and none had been found satisfactory. Frazier’s material answered the problem. Vinyl resins have been found satisfactory upon cheese wrappers, capsules for butter coloring, caps for jars containing food products such as mayonnaise, caps for petrolagar jars, and upon linings for beer and wine cans. As many as twenty-five or thirty different brands of cheese, including a number of the well known popular brands, are packaged in vinyl resin coated foil known as Vinylite. Indeed the vinyl resin coating is apparently suitable for the packaging of almost any kind of food. In respect of commercial success it was made to appear from the testimony that: Commercial use of vinyl resins for packaging food products was extensive before advertising of their availability occurred, and this notwithstanding that their use increased the expense of packaging. The American Can Company, the Hazel-Atlas Glass Company, and the Aluminum Company of America are large users of vinyl resins for food packaging purposes. In 1936 about three and one-half million pounds of vinyl resins were sold and about two-thirds of this amount went into protective coatings, including coatings for metal foil and the lining of cans. Counsel for the Commissioner conceded that Vinylite lining has gone into commercial use on cans.
The Commissioner contends, however, that Frazier’s application discloses no invention. His argument is that it was old to enclose food in wrappers such as tin foil coated with paraffin, or tin foil sealed with paraffin, or tin foil covered with shellac; and he asserts that a vinyl resin had been used as the coating of a gelatine base for a food wrapper, and that the characteristics of vinyl resins were known prior to Frazier. Thus the Commissioner contends that Frazier has done nothing more than substitute a material in a coated food container or wrapper and that the prior art and the known characteristics of the material made the substitution obvious.
The references cited in the Patent Office and relied upon in the trial court and by the Commissioner on this appeal are: Howell, No. 1,057,552, April 1, 1913; Klatte et al., No. 1,241,738, Oct. 2, 1917; Beatty, No. 1,369,159, Feb. 22, 1921; Conomos, No. 1,-529,170, March 10, 1925; Humpert, No. 1,-765,920, June 24, 1930; Young et al., No. 1,775,882, Sept. 16, 1930; and Kratz, No. 1,837,555, Dec. 22, 1931.
We think it unnecessary to discuss in any detail either Beatty or Conomos, for each of these references is in our-view irrelevant. Beatty discloses merely a method of packaging chewing gum, candy or the like in tin foil sealed with paraffin. Cono-mos describes the packaging of confectionery, tobacco products, dairy products, and the like in a wrapping sheet coated with animal jelly. Conomos is not mentioned in the brief of the Commissioner and Beatty is not emphasized.
Humpert’s invention is the coating of tin foil with resin so as to produce a food wrapper capable of resisting organic acids and metallic sulphides. The resin used is shellac, a natural resin, as distinguished from a synthetic resin.2 The witness Doolittle testified that such a coating material would not be successful for packaging' food products in metallic containers for the reason that shellac is brittle and, therefore, would not stand up under the continuous flexing that a foil wrapper must undergo but would crack, and hence no longer protect the food; he also stated that a shellac coating would be quite unsuitable for cans containing liquids because shellac is penetrable by water.
Howell’s invention is a food product wrapper made of tin foil coated on the food [240]*240side with paraffin wax. It is intended to prevent contact of the food with the air, and also to prevent contaminating contact between the food and the foil. In the opinion of Doolittle this invention would not accomplish what was claimed for it, for the reason that paraffin is brittle at low temperatures and non-adherent and, therefore, would not be sufficiently permanent as a foil coating, and also could nót be flexed without cracking, which would -expose the metal; moreover it would be attacked by oils in cheese, which are solvents for wax.-
The Klatte patent discloses the process of obtaining vinyl resins' from vinyl esters by polymerization, explaining that polymerization may be effected by light or heat, or by light and heat combined, and that it can be accelerated by the use of various catalysts.3 The specification states that the properties of vinyl resins obtained through the polymerization process will vary more or less with the catalyst used. Among the products disclosed hy Klatte is an odorless, fireproof film which may be used for coating, lacquering and painting or impregnating various substances such as wood, paper, textile fabric and artificial stone with the effect of imparting high resistance to the action of water, acids, alkalis, and atmospheric changes. There.is no mention of the use of the film for the preservation of foodstuffs. And Doolittle pointed out that there is no disclosure of the use of the film' with metals.
The Young invention is a method of polymerization of vinyl compounds in the presence of tetraethyl lead as a catalyst. Young explains that films containing vinyl resins otherwise prepared had been found to exhibit an objectionable tendency to disintegrate upon long exposure and to darken when heated, these tendencies being especially pronounced when the films were in contact with metal. He -states that it had been assumed that corrosion of the underlying metal by acid developed in the resin was in some measure responsible for the film deterioration, and he points out that films containing resins prepared with tetraethyl lead are more stable in contact with metals. In respect of this invention Doolittle said that it points away from the use of vinyl resins for food packaging because it discloses their inapplicability to use with metal except when prepared in the presence of tetraethyl lead, which is a poison.
The Kratz patent consists of coating a gelatine sheet with a vinyl resin in order to make it more resistant to moisture. The result described is a thin, transparent sheet, substantially moisture proof, and especially adapted for use in the wrapping of candy, bonbons, food, and other perishable material. Doolittle said concerning this invention that it would not be operative in respect of beer cans because gelatine would not adhere to metal, or, if it did, would swell and come off the walls of the container. He pointed out also that Kratz does not refer to the use of vinyl resins on metals, or to metallic food packages.
Summarizing, the prior art teaches the use of tin foil as a food wrapper, and the attempt to use films, such as shellac and paraffin, as a coating. It teaches the use of a vinyl resin film as a lacquer or paint upon wood, paper, textiles and artificial stone.. It teaches also the use of a vinyl resin film on a gelatine sheet wrapper. It teaches also the making and the general properties-of vinyl resins, that is, that they are resistant to water, acids, alkalis and atmospheric changes. But the art does not teach the: use of vinyl resins in contact with metal. In this respect its teaching is not only negative but contrary, for in the only instance in which the use of a vinyl resin film is mentioned in contact with metal it is disclosed that the film disintegrates unless made with, tetraethyl lead, a poison. The art had not answered the need in food packaging of a-coating for metal packaging material which would protect foodstuffs from exterior contamination, be itself resistant to chemical action of the foodstuffs, and which would itself impart no odor or taste thereto.
Frazier has for the first time successfully used a vinyl resin film in contact with metal as aj food container. The question in. the case is, therefore, simply whether this, substitution of a material whose general, properties are known is invention.
We reviewed and stated the law in, respect of substitution of parts in a machine- or of materials in a manufacture as invention in Gasoline Products Co. v. Coe, 66-App.D.C. 333, 87 F.2d 550, 1936, and we there cited the leading cases on the subject The upshot of the decisions of course is-.that there must have been inventive capacity as distinguished from mechanical or-routine skill necessary to accomplish the-substitution. If from the prior art or from, the properties of the thing substituted, the; [241]*241substitution was obvious, no patent is allowable. If, on the contrary, it was not obvious, if inventive capacity was required to see the applicability to the use in question of the thing substituted, and the advantage in new and useful results or increase in efficiency or saving in operation, then a patent is to be granted. In terms of a quotation from Low v. McMaster, 266 F. 518, 519, 520, 3 Cir., 1920, the law has been well epitomized thus:
“ ‘On this subject it is the law, that merely to substitute superior for inferior materials, in making one or more or all of the parts of a machine or manufacture, is not invention, although the substitution may be of materials that are both new and useful in high degree. It is also the law, as exceptions to this general rule, that if the substitution involved a new mode of construction ; or if it developed new properties and uses of the article made; or where it produces a new mode of operation, or results in a new function; or when it is the first practical success in the art in which the substitution is made; or where the practice shows its superiority to consist not only in greater cheapness and greater utility, but also in more efficient action, it may amount to invention.’ ” [66 App.D.C. at page 340, 87 F.2d at page 557.]
Since a vinyl resin film had never, prior to Frazier, been successfully used against metal except when prepared in the presence of a poison, tetraethyl lead, as a catalyst, it at least cannot be said to be clear that Frazier’s substitution was obvious. And if obviousness is doubtful, the doubt may be resolved by the satisfaction of a need which the art, long knowing, has failed to satisfy. “That its [the substituted material] selection was not an obvious thing is persuasively and cogently shown by the fact that during many years numerous inventors were trying to remedy the defects in the old device, and it did not occur to them how simply and satisfactorily this could be done by making the button of rubber or some other elastic or yielding material. * * * When the substitution has accomplished a result which those skilled in the art had long and vainly sought to effect, the evidence that it involved something beyond the skill of the calling is so persuasive that it generally resolves the inquiry in favor of patentable novelty.” George Frost Co. v. Cohn, 119 F. 505, 507, 508, 2 Cir., 1902. Again, “Where the method or device satisfies an old and recog-uized want, invention is to be inferred, rather than the exercise of mechanical skill. For mere skill of the art would normally have been called into action by the generally known want.” Paramount Publix Corp. v. American Tri-Ergon Corp., 294 U.S. 464, 474, 55 S.Ct. 449, 79 L.Ed. 997, 1935. See also United Shoe Machinery Corp. v. E. H. Ferree Co., 64 F.2d 101, 103, 2 Cir., 1933, where the court said: “One of the safe tests of patentability is to inquire as to the condition of the art and the call for improvement.”
Under a further well recognized rule, the utility of a substitution is an important factor in determining its patentability. Smith v. Goodyear Dental Vulcanite Co., 93 U.S. 486, 495, 23 L.Ed. 952, 1876; and see Textile Machine Works v. Hirsch Textile Machines, 302 U.S. 490, 498, 58 S.Ct. 291, 82 L.Ed. 382, 1938; Re Harbeck, 39 App.D.C. 555, 561, 562, 1913.
It is equally well settled that commercial success is strong evidence of utility and patentability. Walker on Patents (6th ed., 1929) § 126. In Yablick v. Protecto Safety Appliance Corp., 21 F.2d 885, 887, 3 Cir., 1927, it was stated that the fact that a process comes immediately into general use and replaces all other like processes is persuasive of invention. This was said upon the faith of Minerals Separation, Ltd. v. Hyde, 242 U.S. 261, 270, 37 S.Ct. 82, 61 L. Ed. 286, 1916, where it was held that the fact that a process was “immediately generally accepted as so great an advance over any process known before that, without puffing or other business exploitation, it promptly came into extensive use . and .. . . largely replaced all earlier processes ... of itself is persuasive evidence of that invention which it is the purpose of the patent laws to reward and protect.”
The substitution in the instant case accomplished within Low v. McMaster more efficient action and the first practical success in the art in which the substitution was made. Within George Frost Co. v. Cohn, Paramount Publix Corp. v. American Tri-Ergon Corp. and United Shoe Machinery Corp. v. E. H. Ferree Co., doubtt if any there be, that the substitution was obvious must be resolved in favor of Frazier. He succeeded in satisfying, where the prior art had failed, a recognized need of some ten years standing. In respect of utility, the evidence in the instant case is such that the rule of Smith v. Goodyear [242]*242Dental Vulcanite Co. and Re Harbeck necessarily operates in FrazieFs favor. It was amply established that a high degree of utility was reached in his substitution of vinyl resins as a coating for metal food packaging materials. And finally Frazier is entitled to the benefit of the rulings of Yablick v. Protecto Safety Appliance Corp. and Minerals Separation, Ltd. v. Hyde in respect of commercial success. Commercial success to an extraordinary extent was established in the instant case; indeed, was conceded by the Commissioner.
Proceeding from the application of elementary rules to the analogy of similar cases, Frazier is entitled to a patent under Gasoline Products Co. v. Coe, where we recognized as patentable the substitution of a chromium alloy in the tubes of a heating coil for cracking hydro-carbon oils. The properties of chromium to resist corrosion generally were known, but the applicant was the first to discover its resistance to sulphur corrosion and to substitute it. And under the leading cases which we reviewed in Gasoline Products Co. v. Coe on the subject of substitution, Frazier is equally entitled to a patent: United Shoe Machinery Corp. v. E. H. Ferree Co. (substitution of aluminum for cast iron in the hammer arm of a clicking machine used in cutting shoe uppers); Re Harbeck (substitution of fused cement for a soluble adhesive for holding together the layers of paper vessels) ; Yablick v. Protecto Safety Appliance Corp. (substitution of copper sulphate for sulphuric acid and pumice in gas masks for the absorption of ammonia from ammonia saturated air); George Frost Co. v. Cohn (substitution of rubber for metal in a hose supporter button); and Low v. Mc-Master (substitution of a solid for a liquid fuel in a vulcanizing apparatus). In each of these cases the general properties of the material substituted were known, but the use of the material in the particular machine or product had long been overlooked and the substitution resulted in satisfying a substantial need in the art with a high degree of utility and commercial success.
Thus both within the elementary rules above stated and by analogy to the leading cases on substitution, the Frazier application should have been recognized as entitled to a patent. The decisions to the contrary in the Patent Office and the trial court were in our view clearly erroneous. Accordingly the decree is
Reversed and the case remanded for further proceedings in accordance with this opinion.