Corona Cord Tire Co v. Dovan Chemical Corporation

• Decision Date: 09 April 1928
• Docket Number: No. 182,182
• Citation: Corona Cord Tire Co v. Dovan Chemical Corporation, 276 U.S. 358, 48 S.Ct. 380, 72 L.Ed. 610 (1928)
• Parties: CORONA CORD TIRE CO. v. DOVAN CHEMICAL CORPORATION
• Court: U.S. Supreme Court

276 U.S. 358

48 S.Ct. 380

72 L.Ed. 610

CORONA CORD TIRE CO.

v DOVAN CHEMICAL CORPORATION.

No. 182.

Argued Jan. 16, 17, 1928.

Decided April 9, 1928.

Messrs. Dean S. Edmonds and Frank E. Barrows, both of New York City, for petitioner.

[Argument of Counsel from pages 359-361 intentionally omitted] Messrs. John W. Davis and James J. Kennedy, both of New York City, for respondent.

[Argument of Counsel from pages 362-364 intentionally omitted] 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 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 April 11, 1927 (273 U. S. 692, 47 S. Ct. 570, 71 L. Ed. 843), because in the prior case of Dovan Chemical Corporation 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 thorougly 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 accelera- tor in the vulcanization of rebber, 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 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 'under cured' or 'over cured,' 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 is business.

It has been known that a 'cure' can be hastened by mixing with the ingredients a small quantity of what 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 ac- tion 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, 157, 23 L. Ed. 267; Stow v. Chicago, 104 U. S. 547, 550, 26 L. Ed. 816; Lovell Mfg. Co. v. Cary, 147 U. S. 623, 634, 13 S. Ct. 472, 37 L. Ed. 307.

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...