Corona Cord Tire Co. v. Donovan Chem. Corp.
276 U.S. 358 (1928)

Annotate this Case

U.S. Supreme Court

Corona Cord Tire Co. v. Donovan Chem. Corp., 276 U.S. 358 (1928)

Corona Cord Tire Company v. Donovan Chemical Corporation

No. 182

Argued January 16, 17, 1928

Decided April 9, 1928

276 U.S. 358




1. Discovery that a change of ingredients in a process speeds the result entitles the inventor to any other advantages flowing from the substitution. P. 276 U. S. 369.

2. The fact that a party was the first to discover and obtain a valid patent for a process of producing a substance held irrelevant to the question whether he was the first discoverer of its utility as an ingredient in another process. P. 276 U. S. 370.

3. Under Rev.Stats. § 4886, a person is not to be denied a patent because of a publication printed after his discovery and not more than two years before his application. P. 276 U. S. 372.

4. Invention of a process for vulcanizing rubber, and its reduction to practice, may be established by proof of actual tests in which test

Page 276 U. S. 359

slabs of rubber, properly vulcanized, were made. Production of rubber goods for use or sale was not indispensable. Pp. 276 U. S. 373, 276 U. S. 383.

5. Reckless overstatements of the extent of earlier reduction to practice by the applicant, made in affidavits filed in a patent proceeding to meet a reference of prior publication, held not destructive of the presumption of validity accompanying the patent where the sufficiency of the affidavits in other respects rendered such statements superfluous. P. 276 U. S. 374.

6. Where a patentee met a reference in the patent proceeding merely by evidence of his own priority of discovery, his failure then to attack its sufficiency in other respects did not subject him to the burden of proving it insufficient in a suit to enjoin infringement of the patent. P. 276 U. S. 374.

7. The findings of a trial court which heard the witnesses are not conclusive here when contrary to the findings of the circuit court of appeals made in the same case, and of the trial court in another case, upon the same evidence. P. 276 U. S. 375.

8. Priority of discovery may be proved by one witness, not financially interested, in connection with other circumstances. P. 276 U. S. 382.

9. One who first discovered and proved the utility of an improvement in a process cannot be said to have abandoned his invention, as against a subsequent discoverer or patentee, because he did not use the discovery commercially or apply for a patent. P. 276 U. S. 384.

10. A claim to the exclusive use of a large group of related chemical compounds, unsupported by proof that all have a common quality rendering each useful in the process patented, is too broad. P. 276 U. S. 385.

11. Patent No. 1,411,231, issued March 28, 1922, to Weiss for a process of vulcanizing rubber by combining with the rubber compound, diphenylguanidine, or "a disubstituted guanidine," and for the vulcanized product, held invalid. P. 276 U. S. 385.

16 F.2d 419 reversed.

Certiorari, 273 U.S. 692, to a decree of the circuit court of appeals which reversed a decree of the district court, 10 F.2d 298, dismissing a bill to enjoin infringement of a patent. See also Dovan Chemical Corp'n v. Nat'l Aniline Co., 292 F. 555.

Page 276 U. S. 364

MR. CHIEF JUSTICE TAFT delivered the opinion of the Court.

This is a bill by the Dovan Chemical Corporation against the Corona Cord Tire Company to enjoin infringement of a patent issued to Morris L. Weiss, assignor of the Dovan Chemical Corporation. The district court

Page 276 U. S. 365

for the Western District of Pennsylvania dismissed the bill for lack of validity of the patent. 10 F.2d 598. The dismissal was reversed, and the patent and the infringement charged were both sustained by the Circuit Court of Appeals for the Third Circuit. 16 F.2d 419. A writ of certiorari was granted, 273 U.S. 692, because in the prior case of Dovan Chemical Corp. v. National Aniline & Chemical Company, 292 F. 555, the Second Circuit Court of Appeals had reversed the decree of the District Court for the Southern District of New York (not reported) in favor of the Dovan Corporation, and had held that the patent was invalid on the ground that Weiss was not the first discoverer.

The patent in suit relates to the vulcanization of rubber. Vulcanizing consists in mixing a small amount of sulphur with rubber and subjecting the mixture to heat for a period of time, during which a chemical combination of the rubber and sulphur takes place and commercial rubber is made. The patentee recites that the object of his invention is to

"improve rubber compounds so that the finished product shall be of superior quality and so that the time required for vulcanization shall be greatly reduced over that ordinarily required for such a purpose. It is known that, when certain organic substances are added to the rubber mix during the compounding, a catalytic or similar action is produced which causes the rubber or similar gum to unite or react more rapidly and thoroughly with sulphur or other vulcanizing agents."

The patentee continues: "I have discovered that disubstituted guanidines, particularly diphenylguanidine, is particularly effective for this purpose." (This substance is indicated by the formula given in the patent.)

He says further:

"I am aware that triphenylguanidine has been suggested, and probably used to some extent, as an accelerator

Page 276 U. S. 366

in the vulcanization of rubber, but the use of diphenylguanidine for that purpose appears to have been unknown prior to my researches on this substance."

"I have found that diphenylguanidine is much more powerful and efficacious as an accelerator in vulcanization than triphenylguanidine. For example, in the vulcanization of hard rubber articles, the use of diphenylguanidine not only hastens the vulcanizing action, but results in a final product much superior in texture, strength, durability, and aging qualities over that when the triphenylguanidine is used."

The patentee makes a short reference to a formula by which he produces the rubber mix, in which he says:

"The rubber may be compounded in the following proportions: 50 parts by weight of new rubber, 45.5 parts by weight of zinc oxide, 3.5 parts by weight of sulphur, 1 part by weight of diphenylguanidine. These are mixed together in any suitable way, such as by milling, and then vulcanized or cured in the usual molds or otherwise under heat corresponding to a steam pressure of about 40 lbs. per square inch. This vulcanizing temperature should be continued until the compound is suitably vulcanized, which requires from 10 to 20 minutes, depending upon the shape and size of the articles being vulcanized."

The patent contains twelve claims. Those mainly relied on are: the fourth, for "the process of treating rubber or similar materials which comprises combining with the rubber compound diphenylguanidine;" the eighth, for "the process of treating rubber or similar materials, which comprises combining with the rubber compound a vulcanizing agent and diphenylguanidine;" and the twelfth, for "a vulcanized compound of rubber or similar material combined with a vulcanizing agent and diphenylguanidine."

Vulcanizing is old and well known. Its present high state of development represents an evolution of about 80

Page 276 U. S. 367

years. Practically all rubber must be vulcanized for commercial use. The amount of sulphur in the mixture is comparatively small, as, for instance, 4 to 10 parts of sulphur to 100 parts of rubber. The remainder of the mixture may be all rubber or it may be partly rubber and partly other ingredients such as fillers and pigments, the other ingredient used most widely being zinc oxide. In the manufacture of automobile tires, a considerable proportion of zinc oxide is generally used. A very old and well known proportion has been 50 parts of rubber, 45 parts of zinc oxide and 5 parts of sulphur, and is the one shown in the specification of the patent. The mixture is "cured" by subjecting it to heat to make the vulcanized rubber of commerce. Platen molds have to be provided for giving the desired form to the rubber vulcanized. Steam has to be supplied for heating the molds and the rubber mix during the "cure." A "cure" is the successful completion of the chemical union or vulcanization of the rubber with the sulphur. The fact of a successful "cure" for practical purposes is established by a simple and short method called the thumb and tooth test. By this test, rubber chemists settle the fact and determine by the resulting product the satisfactory quality of the stock or the mix for vulcanization, and they become expert at it. If by this test the product is not well united chemically, it is said to be "undercured" or "overcured," and then the operator changes the ingredients or the time of the process. When it is important to determine with greater exactness the tensile strength and degree of elasticity or other qualities of the product, a special machine measure or test is used, but the thumb and tooth test is the frequent way of knowing a cure, and it is a satisfactory one for everyday use in business.

It has been known that a "cure" can be hastened by mixing with the ingredients a small quantity of what

Page 276 U. S. 368

is called an accelerator or vitalizer. Inorganic substances like lime or litharge were originally employed as such, but it was subsequently found that certain organic substances were more powerful, or more "active," as the term is, and they came into more general use. The heat to which the rubber mixed with sulphur is subjected has a deleterious effect upon the substance of the raw rubber, and the longer the heating, the greater the injury. An accelerator, as it lessens the time of the cure, not only increases the output of the equipment used but reduces the danger of deterioration of the product. An accelerator thus improves the elasticity, tensile strength, and other desirable commercial qualities of the finished product. It is not fully understood what the vitalizing or catalytic action of the accelerator is, but its existence and its results have long been known.

The patentee, in his specifications, speaks of triphenylguanidine, and compares its operation as an accelerator with that guanidine, the utility of which as an accelerator he claims to have discovered, called diphenylguanidine. Guanidines are a group of organic substances which have become prominent and important in this quest for useful accelerators. The monophenylguanidine and the diphenylguanidine and the triphenylguanidine are closely related chemically. Their long names, used to indicate the variation in the component elements, have been shortened so that it is usual to refer to diphenylguanidine by letters as "D.P.G." and the triphenylguanidine as "T.P.G."

So closely do the chemical compositions of these two resemble each other that the petitioner contends that the patent is invalid because the utility of D.P.G. as an accelerator was plainly indicated by general chemical knowledge, and did not involve patentable discovery after T.P.G. had proven to be a good one for this purpose. But we cannot agree with this view. The catalytic action

Page 276 U. S. 369

of an accelerator cannot be forecast by its chemical composition, for such action is not understood, and is not known except by actual test.

The respondent attempts to show that the resulting improvement in the rubber product by the use of diphenylguanidine was something different from that in the use of other accelerators. The good results of the use of diphenylguanidine are chiefly or wholly due to its greater activity and the lessened time of the cure. The expert evidence seems to show that T.P.G. as an accelerator develops the same desirable qualities, set forth on behalf of respondent, in the vulcanized rubber as does D.P.G., except that the cure of the latter is more rapid with its to be expected advantages. Moreover, claims of peculiar usefulness of D.P.G. in other than its "activity" and speed as an accelerator, even if proven, could not in any degree affect the issue in this case. If employment of D.P.G. as a useful accelerator was a discovery by Weiss, prior to any one else, Weiss, or his assignee, is entitled to all the advantages that flow from that increased activity or from any other quality in its use as such. Roberts v. Ryer,91 U. S. 150, 91 U. S. 157; Stow v. Chicago,104 U. S. 547, 104 U. S. 550; Lovell Mfg. Co. v. Cary,147 U. S. 623, 147 U. S. 634.

It does not, on the other hand, give Weiss any more right to appropriate D.P.G. as an accelerator because he may have elaborated in his specifications other advantages from its use than if he had not mentioned them. Nor, on the other hand, does it minimize or affect the priority of completed discovery by some one else before Weiss that the prior discoverer may not have perceived and stated all the advantages of an earlier use of D.P.G. as an accelerator.

Judge Hough, of the Second Circuit, truly said, therefore, that this patent meant, condensed in one sentence: "I claim the use of D.P.G. as an accelerator, because I

Page 276 U. S. 370

was the first person who observed its efficacy for that purpose."

Similarly, the examiner in the Patent Office who allowed the patent said that Weiss' application was "no more than a broad disclosure of the use of [D.P.G.] without disclosing any details other than those usually employed with accelerators of this class."

The patent in suit was applied for November 12, 1921, and was granted March 28, 1922. Weiss had referred in the specifications of this patent to another patent of his which was applied for July 2, 1921, and granted July 11, 1922. This latter patent was for a process for making D.P.G. in large or commercial quantities. In the application for that patent, the patentee pointed out that, before his process was discovered, D.P.G. could not be made except in small quantities for chemical research because the cost was prohibitive. The validity of the Weiss patent for a process in making diphenylguanidine is not attacked. The new patented process, by reason of the lessened cost ,has resulted in the very great use of D.P.G. for commercial purposes, and has been very profitable. But the purpose of securing the patent in suit and maintaining its validity is more ambitious. It is not to protect and preserve the new process already being safely enjoyed, but it is to prevent the use of D.P.G. as an accelerator, however made by any process that may be subsequently discovered. It is to enlarge a monopoly of D.P.G. as an accelerator, and is thus in effect to discourage effort to find other and cheaper means of making it. What we have to decide here is not the priority of discovery of the cheap process of making the accelerator D.P.G., which it is conceded Weiss invented, but whether he was the first person to discover the efficacy of D.P.G. as an accelerator. whether made by any process, cheap or costly.

Page 276 U. S. 371

We feel it necessary to call attention to a lack of relevancy of Weiss' successful process patent in the case before us because the majority opinion in the circuit court of appeals seems to us erroneously to have confused the credit due to Weiss for the process patent, already conceded, with his right to his present claim of entire monopoly of the use of D.P.G. as an accelerator.

The issues and the evidence in this case cannot be considered and discussed without reference to a paper read by Dr. George Kratz, a rubber chemist at the Philadelphia meeting of the American Chemical Society between the 2d and the 6th of September, 1919. It was entitled "The Action of Certain organic Accelerators in the Vulcanization of Rubber," and was a review of the comparative excellence of a number of well known and used accelerators, as well as that of D.P.G. with T.P.G., in which he found D.P.G. to be very much more active than T.P.G. Then, under an experimental part, he described the kinds of rubber used, the proportions of rubber and sulphur in the mixture, and the manner in which the accelerator was incorporated and the method of vulcanization. He said:

"The rubber used was good quality, first latex, pale crepe, and the same lot was employed in all mixtures. All mixtures were made under standard conditions; the average time of each batch on the mill was 17.5 min. The same proportion of rubber and sulphur -- 92.5 parts rubber, and 7:5 parts sulphur -- was employed in each instance, but the amount of accelerator was varied according to the conditions of the experiment."

"All the accelerators soluble in alcohol were dissolved in the smallest quantity of this liquid and introduced into the rubber in solution. Those not soluble -- and this applied to the anhydroformaldehyde bodies only -- were

Page 276 U. S. 372

ground to 100 mesh and added to the rubber with the sulphur. After mixing, the mixtures were allowed a recovery period of 24 hrs. before they were vulcanized. Vulcanization was carried on in a platen press of the usual type."


Parts Required to Equal One Part Aniline

Aniline . . . . . . . . . . . . . . 1.000

Urea. . . . . . . . . . . . . . . . O.250

Thiourea. . . . . . . . . . . . . . O.300

Monophenylthiourea. . . . . . . . . O.450

Diphenylthiourea. . . . . . . . . . O.850

Monophenylguanidine (a) . . . . . . O.075

Diphenylguanidine (Sym.). . . . . . O.075

Triphenylguanidine. . . . . . . . . O.500

The activities of the various substances were compared in the mixture previously mentioned -- 92.5 parts of rubber and 7.5 parts of sulphur -- taking as a standard the effect obtained with one part of aniline, vulcanized for 90 min. at 148

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