Application of Ralph E. Miegel and John J. Verbanc

404 F.2d 378, 56 C.C.P.A. 761

• Court: Court of Customs and Patent Appeals
• Decided: December 5, 1968
• Docket: Patent Appeal 8011
• Status: Published

Opinions

ALMOND, Judge.

This is an appeal from the decision of the Board of Appeals affirming the rejection of claim 3, the only claim in appellants’ application.¹

Appellants’ invention is a curable composition of butadiene-styrene copolymer and bis (2,6-dimethylmorpholinothio-carbonyl) monosulfide. The monosulfide acts as a vulcanization accelerator for the butadiene-styrene copolymer elastomer and is said to afford fast and effective cures of the butadiene-styrene rubber while exhibiting an exceptional degree of processing safety.

The claim on appeal reads as follows:

3. A composition exhibiting fast curing and improved processing safety comprising a butadiene-styrene co-polymer and from about 0.4 to about 1.5 parts by weight of bis (2,6-di-methylmorpholinothioearbonyl) mono-sulfide per one hundred parts of said copolymer.

The references are:

Naunton et al. 1,867,982 July 19,1932 (Naunton)

Whitby, G.S., Synthetic Rubber, John Wiley and Sons, Inc., New York 1954, p. 392 (Whitby)

Naunton discloses that morpholine thiuram monosulfides and polysulfides, as well as homologs and derivatives of morpholine, are “safe” super-accelerators for rubber. The patentee states that the homologs and derivatives of morpholine as well as morpholine itself may be prepared in the manner described in the reference patent to Payman.

Payman discloses a method for the manufacture of morpholine, its homologs and derivatives and specifically discloses the preparation of 2,6-dimethyl-morpholine. Payman further states that in the reference patent to Naunton there are disclosed processes for converting these morpholine compounds into other compounds which are useful in processes of vulcanizing rubber.

Whitby states that thiuram mono-sulfides and thiuram polysulfides are very good accelerators for GR-S2 and can be used in GR-S with less danger of scorching than in natural rubber.

The issue here is obviousness under 35 U.S.C. § 103.

The examiner rejected the claim as unpatentable over Naunton in view of Payman and Whitby. Noting that Naunton, with specific reference to Pay-man, teaches that homologs and derivatives of morpholine thiuram mono-sulfides “are accelerators for rubber which do not exhibit the tendency to induce scorching as well as having the capacity to activate a rapid cure” and that Payman specifically discloses 2,6-dimethylmorpholine as a precursor for the thiuram monosulfides, the examiner considered it obvious to convert the precursor to the thiuram monosulfide of the claim “using the same well-known procedures disclosed both by the primary reference and by appellants, to produce a compound which is used to impart fast curing and improved processing safety.” Stating that the two reference patents “are directed towards the preparation of vulcanization accelerators” for natural rubber, the examiner further considered it obvious to employ the claimed monosulfide as an accelerator for butadiene-styrene copolymer (GR-S rubber) in view of the teaching by Whit-by that the general class of thiuram monosulfides are good accelerators having less danger of scorching in GR-S rubber than in natural rubber.

The board, in affirming the rejection, added that since Payman “describes no other specific homolog of morpholine than 2,6-dimethylmorpholine, it would appear that this intermediate was offered as the preferred, or prototype, intermediate for the accelerator.”

We agree with the examiner and the board that it would be obvious to convert the 2,6-dimethylmorpholine precursor of Payman to the monosulfide of the claim and employ the monosulfide as an accelerator in composition with butadiene-styrene copolymer in view of Naunton’s explicit reference to Payman as a source of morpholine compounds for vulcanization accelerators and Whitby’s clear teaching that thiuram monosulfides are good accelerators for butadienestyrene copolymer. It is noted that the appellants urge no patentable distinction or critical significance in the claimed proportions.

Appellants argue, however, that their invention is patentable because of unexpectedly improved curing results obtained by their composition. In support of this argument, appellants direct our attention to two Rule 132 affidavits in the record. While the examiner did not disagree with the affidavits’ showing, he felt that relative processing safety of the compared accelerators would be expected and any differences to be differences of degree only. The determination of the best accelerator for one's use was considered to be a matter of routine experimentation. The board found the comparative tests to “provide uncertain evidence of the superiority of appellants’ accelerator as compared with even the arbitrarily selected homologs of the prior art.” The appellants’ attempt to show that other homologs have a lesser safety was said to appear to “create an artificial problem of selection.” The combined affidavits of Dr. Gruber show that appellants’ accelerator has a greater scorching time, corresponding to an increase in processing “safety,” compared to five other structurally similar accelerators in combination with a specific butadiene-styrene copolymer.

We agree with the board and solicitor that the comparative tests, limited to a particular copolymer of butadiene-styrene, are insufficient to establish similar superiority for the accelerator with all copolymers of butadiene-styrene within the scope of the claim and are inadequate to overcome the strong suggestion of obviousness inferred from the references.

Moreover, we agree with the examiner that, inasmuch as the art teaches that the morpholine thiuram monosulfides and disulfides are “safe” accelerators for vulcanizing rubber and since it would not be unreasonable to expect that individual accelerators would tend to vary in this effect with the same or different rubbers, “merely testing to determine the relative degrees of processing safety and finding a particular thiuram sulfide exhibiting a higher or lower degree would be expected.” Obviousness does not require absolute predictability. In re Crounse, 363 F.2d 881, 53 CCPA 1390; In re Sebek, 347 F.2d 632, 52 CCPA 1442; In re Moreton, 288 F.2d 940, 48 CCPA 928. We are unable to find “clear and convincing evidence,” as required by this court in In re Lohr, 317 F.2d 388, 50 CCPA 1274, that appellants’ accelerator possesses unexpected processing safety as compared to the other thiuram mono-sulfides. In re Wetterau, 356 F.2d 556, 53 CCPA 916.

Appellants urge, also, that the claimed composition is patentable because the reference patents teach the preparation of “hundreds of individual compounds” while not mentioning appellants’ specific accelerator. However, we find that the accelerator of the claim is clearly suggested to one of ordinary skill in the art by the combined teachings of the patents since, as urged by the solicitor, the morpholine homolog, 2,6-dimethylmorpholine, is one of only three precursors specifically described by Pay-man for use in forming the Naunton accelerators, of which are disclosed substantially only three categories including the morpholine thiuram monosulfides. The use of the thiuram monosulfide thus obtained as an accelerator for butadienestyrene would not be unobvious in view of the teaching of Whitby that thiuram sulfides are even more effective with the GR-S rubbers (butadiene-styrene copolymers) than with natural rubber in preventing scorching.

We agree with the conclusion of the board that the claim on appeal is obvious in view of the cited references.

The decision of the board is affirmed.

Affirmed.

SMITH, Judge, participated in the hearing of this case but died before a decision was reached.

1 . Serial No. 110,636, filed May 17,1961, for “Process and Products.”

2 . The Condensed Chemical Dictionary (Reinhold Publishing Corp., New York, Sixth Edition, 1961) defines “GR-S” as follows :

GR-S. Abbreviation for government rubber-styrene. * * * Produced by emulsion polymerization of 75 parts butadiene and 25 parts styrene, and also referred to as Buna-S. The more accepted designation now is SBR (styrene-butadiene rubber).

That GR-S refers to butadiene-styrene copolymer is not in dispute here.