Opinion ID: 1506575
Heading Depth: 1
Heading Rank: 1

Heading: The Latex Patent

Text: In the year 1905 the open-top or sanitary tin can was invented; i. e. a can with a detachable top. Generally the joint between can and cover has to be air tight, and various expedients were tried to make it so; rubber rims, paper gaskets, rubber cement solutions. None of these was satisfactory, so that in 1922, when Hopkinson and Dewey made their invention, the art had waited over sixteen years for a suitable seal. What these inventors disclosed was very simple; nothing more than the use of latex  the natural sap of the rubber tree  as much concentrated as was desired, and usually preserved with ammonia. By this method the amount of rubber in the seal was increased much above that in rubber solutions and rubber rims, and the life of the seal was greatly prolonged because of the physical structure of the latex globules. Beginning with the year 1922 latex became the standard material for seals, and has very largely displaced all other substances; not the mere latex of the patent-in-suit, however, for it very quickly developed that that alone was not feasible mechanically. The art required the seal to be laid upon the cover while the cover was rotating at high speeds, and also that the covers, when completed, should be inspected by an operative who laid them top down along her arm in a slanting position. No concentration of latex was possible which would at once run with enough fluidity to be squirted into the groove of the cover, and yet when deposited would not splash out under the centrifugal force of rotation, and would not run unevenly to one side while being inspected. For these reasons the invention, while serviceable under ideal conditions, did not answer the actual needs of the art; it was the second patent that supplied its deficiencies. Latex is a watery substance in which the rubber particles float in colloid form; the advantage of using it is that concentration  i. e. driving off a part of the water  does not injure the particles but only brings them nearer together, the native elasticity of the rubber being retained. The substance had been known for many years; patents for its use go back for over a hundred years; e. g. Hancock's British Patent (1825) No. 5122. Nevertheless, it had not become commercially available in quantity (for it did not carry well except in expensive containers) until Milne disclosed in 1914 a method of shipping it cheaply as a concentrate. (British Patent to Samuel Milne (1914) No. 24,680.) Thereafter it went into large industrial use in Europe, but it was not extensively imported into this country before 1920, by which time new ways of preserving it had been discovered. There is therefore not much antecedent evidence that the invention demanded high originality, even if latex had never before been used to make a seal. As we have said rubber was an old material for that purpose, and latex is only another form of rubber; the patent merely recommended its use as a substitute within a year or two after it became possible to obtain it. We do not mean that the mere substitution of materials cannot be an invention. Smith v. Goodyear Dental Vulcanite Co., 93 U.S. 486, 23 L.Ed. 952; Akme Flue v. Aluminite Flexible Flue Cap Co., 2 Cir., 27 F.2d 736; United Shoe Machinery Corp. v. E. H. Ferree Co., 2 Cir., 64 F.2d 101; Samson-United Corp. v. Sears, Roebuck & Co., 2 Cir., 103 F.2d 312. When for example a material has been available for many years, and no one has thought to use it in a new physical combination to answer a need equally old, there is as much reason for treating its selection as evidence of invention as the selection of any other element; and it is unfortunate that loose statements, thrown out arguendo, have at times seemed to give to the substitution of new materials a different standing from that of other combinations  often indeed the question has been quite unnecessarily confused with that of a new use. The difficulty in the case at bar is not therefore that the invention consisted only of a substitution of material, but that the necessary setting did not exist for any invention at all. It is not important that latex had been known for many years, and that a convenient method of shipping it had been known for eight years. We should not count elements that were not commercially available; a substance, long known to chemists, but not upon the market, is practically as impotent upon the art as though it were unknown. The assumption of the law is that the chance of profit from the exploitation of the patent will stimulate discovery, and profit presupposes that the materials are at hand. Regardless, however, of whether this reasoning without more evidence would invalidate the patent, the patent to Milne, just mentioned gives it its coup de grace. In that patent occurs the following passage (page 3, lines 22-24): The concentrated latex, preferably while hot, is placed in suitable air and watertight vessels of convenient shape or construction, the joints being sealed, if necessary, by a coating or lining of latex which on drying ensures tightness. The invention of the Latex Patent therefore amounted to no more than making use of Milne's disclosure upon can covers about one year after it became commercially possible to do so; i. e. to do so in quantity. That would scarcely have been enough, even if the new use had answered the needs of the industry. As we have said, it did not; it was indeed one step forward, but the art was not satisfied.