Application of Bruce W. Hotten, 411 F.2d 1341 (C.C.P.A. 1969)

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U.S. Court of Customs and Patent Appeals (1909-1982) - 411 F.2d 1341 (C.C.P.A. 1969) June 26, 1969

Bertram I. Rowland, San Francisco, Cal., attorney of record, for appellant.

Joseph Schimmel, Washington, D. C., for the Commissioner of Patents. Raymond E. Martin, Washington, D. C., of counsel.

Before RICH, Acting Chief Judge, NICHOLS and NEESE, Judges, sitting by designation, and ALMOND and BALDWIN, Judges.

RICH, Acting Chief Judge.

This appeal is from the decision of the Patent Office Board of Appeals affirming the examiner's rejection under 35 U.S.C. § 103 of claims 1-6 of application serial No. 451,068, filed April 26, 1965, for "Complex Aluminum Greases of Enhanced Stability."

Appellant acknowledges in his application that " [c]omplex aluminum carboxylate greases are well known in the art," referring, inter alia, to his own patent, No. 2,599,553, issued June 10, 1952, for a disclosure of such greases. As described both in that patent and in the application, those greases comprise hydrocarbon oils of lubricating viscosity combined with certain complex aluminum soaps as thickeners, the soaps having "at least two dissimilar substantially hydrocarbonaceous organic anions * * *." Both anions are generally oleophilic but one, derived from long chain fatty carboxylic acids containing 8 to 30 carbon atoms (stearic acid, for example), is more soluble in the oil than the other which is derived from an aromatic carboxylic acid, such as benzoic acid. According to the specification, a problem existed with respect to those prior-art greases:

It is found, however, that after long periods of time, particularly at elevated temperatures, the grease begins to liquefy. In attempting to stabilize the grease, many of the known commercial stabilizing agents are found to be ineffective or have detrimental side effects, particularly in the presence of common additives, such as the filler, zinc oxide, or the common rust inhibitor, sodium nitrate. [Emphasis ours.]

To solve the liquefaction or grease breakdown problem and "to provide a composition with enhanced stability at elevated temperatures," appellant has added to those greases, according to the present invention, 0.1 to 20 per cent by weight of lithium, sodium, or potassium salts of certain aromatic carboxylic acids — the sodium salt of benzoic acid, for example, the preferred additive. In Table I of his specification, appellant presents comparative results of a "Thin Film Life Test"1  conducted at 250°F. on various complex aluminum carboxylate greases to which 0%, 1% or 5% by weight sodium benzoate has been added. The "Thin Film Life" of those greases was in the range of 24-48 hours with no additive, 120 hours with 1% additive, and 168-1128 hours with 5% additive, varying with different grease compositions. Appellant further states, apparently justifiably;

It is evident from the above table that a great extension of useful life is obtained by the addition of sodium benzoate — as exemplary of alkali metal aroates — to the aluminum complex greases.

Claim 1 is representative:

1. A lubricating oil composition comprising an oil of lubricating viscosity and in an amount sufficient to thicken said oil to a grease, a compound of the formula:


in which R is an aliphatic group having from about 8 to 30 carbon atoms, R' is selected from the group consisting of hydrogen and a lower aliphatic hydrocarbon radical, at least one-half of R' being hydrogen, and Ar is an aromatic hydrocarbon of from 6 to 11 carbon atoms, x is at least 0.25, y is at least 0.25, the sum of x and y is from 1.5 to 2.5, z is from 0.5 to 1.5, and the sum of x, y and z is 3, and

in an amount sufficient to provide stabilization an alkali metal aroate of from 7 to 12 carbons, wherein said metal is of atomic number 3-19. [Emphasis ours.]

The sole novelty is defined by the emphasized clause.

The references are:

Ricketts 2,182,137 Dec. 5, 1939 Licata 2,431,760 Dec. 2, 1947 Hotten 2,599,553 June 10, 1952

Hotten discloses little more than what appellant's specification acknowledges to be known to the art, as discussed earlier in this opinion, namely, that mixed organic anion aluminum soaps — aluminum benzoate stearate, for example — are useful as thickeners in making grease from lubricating oils. According to the Hotten patent:

The complex aluminum soaps are particularly useful in greases. These soaps impart to the grease composition high melting point and resistance to emulsification in water, * * *.

Ricketts discloses grease compositions comprising a lubricating oil, a sodium fatty acid soap "with which other alkali metal or other metal soaps may or may not be incorporated," and "a small quantity of a metal salt of an organic carboxylic acid containing an aromatic ring." Exemplary of the metal salts used as additives are sodium benzoate and aluminum benzoate, among others named. According to Ricketts, the objects he achieves by his additives are the production of a grease having a higher melting point than conventional mineral oil soda soap greases, concomitantly (1) "producing a lubricant which is suitable for use at high temperatures," (2) "preventing or reducing leakage of the lubricant from the bearings at high temperatures," (3 "improving the stability of the grease at normal and at high temperatures," and (4) improving "the stability of such a grease, as indicated by freedom from granulation, by absence of any tendency to `bleed' or separate either during manufacture or later in storage, and by resistance to breakdown from mechanical stirring or beating." In various examples, a soda soap grease containing sodium benzoate evinced "no bleeding" as a result of heat treatment at 300-500°F. for 24 hours, at 200-250°F. for 72 hours, or upon "storage after heating for several months"; such a grease also "assumes mineral oil fluidity at considerably higher temperatures" than a grease not containing sodium benzoate. Upon completion of a bearing test for 20 minutes at 150°F., the sodium benzoate-containing grease "remained unchanged in appearance and structure" with "no evidence of breakdown or of separation of oil and soap." In a similar test for 30 minutes, applying heat to a maximum of 450°F., " [s]imilar results were obtained, save that between 240 and 400°F. streamers of grease made their appearance above the plane of the bearing; * * *."

It is unnecessary to discuss Licata's disclosure beyond noting how the examiner employed it in the following restatement of his rejection in his Answer:

Claims 1-6 are rejected as unpatentable over Hotten in view of Ricketts and Licata (35 U.S.C. 103). Hotten shows the instantly claimed complex aluminum soap greases to be old in the art. Ricketts shows soda soap greases of improved stability against leakage of the lubricant from the bearings at high temperatures. A small quantity of a metal salt of an organic carboxylic acid containing an aromatic ring is incorporated into the grease to improve stabilities. Samples [Examples?] of both light and heavy metals [which] may be employed [are given]. Examples of suitable salts are sodium and potassium benzoate. Licata shows aluminum-base greases and aluminum soaps of saturated higher fatty acids that are highly stable, in storage and use, against any separation or syneresis by incorporating into the greases a lithium soap of a fatty acid. Hence, it would be obvious to improve the stability of the old greases of the primary reference with the known grease stabilizers of Ricketts and especially in light of Licata's teaching that the metals may be different in the stabilizers and the greases. Regardless of the differences in the greases, one would expect somewhat similar problems of instability and how to improve the stability is obviously within the prior art teachings and the skill of the art. Moreover, in following the teachings of Ricketts and Licata appellant has solved the same problems for complex aluminum greases as for aluminum-based and soda soap greases * * *. [Emphasis ours.]

Evidently, the examiner further thought the general problem of "stability" and the particular problem of liquefaction to be common to soda soap and complex aluminum soap greases, for he also stated:

Appellant's problem is one of liquefaction at elevated temperatures which is a problem solved by Ricketts at high temperatures by preventing leakage of the lubricant and other instabilities of the grease. [Emphasis ours.]

The board agreed. The essence of its opinion is in the following passage from its opinion, summarizing the rejection with which it agreed:

It appears to be the Examiner's position that since the Ricketts patent shows the addition of sodium benzoate to sodium soap greases to stabilize them at both normal and high temperatures, and particularly against bleeding, it would have been obvious to add this compound to the aluminum soap greases of Hotten for the production of the same results. He considers this conclusion to be further supported by Licata who shows the occurrence of the same bleeding or syneresis problem with certain aluminum soap greases and its solution by the addition of a lithium soap of a fatty acid. [Emphasis ours.]

We agree with appellant that the examiner and board erred in failing to appreciate the specific stability problem appellant encountered with his particular complex aluminum soap grease. True, Ricketts does disclose that sodium and other metal benzoates are effective to solve certain stability problems present in soda soap grease. The examiner especially relied on Ricketts' disclosure that adding sodium benzoate to a soda soap grease prevented leakage of lubricant from bearings at high temperatures, equating such leakage with liquefaction. The board, in turn, seems to have placed some reliance on Ricketts' disclosure that "bleeding"2  during storage at normal or high temperatures is reduced by adding sodium benzoate to the soda soap grease.

Appellant, however, has convinced us that the particular stability problems solved by Ricketts with respect to soda soap grease are of a different nature than the "liquefaction" problem he faced with his complex aluminum soap greases. We think appellant is correct in pointing out that Ricketts' observation of no leakage of his grease from a bearing during a test carried out for a period of but 20-30 minutes is no indication at all of the long-term stability of complex aluminum soap grease against liquefaction of the grease sought and achieved by appellant, and certainly would not suggest that the effective life of a complex aluminum soap grease could be increased from about 1-2 days to 7-47 days by adding sodium benzoate to that grease.

With respect to the board's reliance on the reduction in bleeding during heating or storage disclosed by Ricketts for his sodium benzoate stabilized soda soap grease, the problem of "bleeding" or "syneresis,"3  too, appears different from the problem of liquefaction. As we understand it from the references in this grease art, "bleeding" or "syneresis" involves leakage or separation of some liquid lubricant out of the solid, soap-thickened grease structure without total breakdown of the grease. On the other hand, "liquefaction," as the expression itself implies, appears to involve liquefying of the entire grease structure over an extended period of time. Moreover, appellant quotes from another of his own prior patents, No. 2,768,138 referred to in his specification, passages showing that his complex aluminum soap grease starting material already has a reduced tendency to "bleed." Appellant argues, correctly we think, that one of ordinary skill in the art would regard the problems of "bleeding" and "liquefaction" as different and would have no occasion to add Ricketts' sodium benzoate to the complex aluminum benzoate-stearate grease of Hotten to solve a nearly non-existent problem of bleeding in that grease.

In short, we find no suggestion in Ricketts, or elsewhere in the record, that sodium benzoate would solve the problem of liquefaction of complex aluminum soap greases which occurs after relatively long periods at elevated temperatures. We think the claimed invention is unobvious.

The decision of the board is reversed.



While the nature of the "Thin Film Life Test" is not entirely clear from the specification, appellant explained it in the following terms in his brief before the board:

In order to demonstrate the effect of the sodium benzoate on the complex aluminum greases, the thin film life of the greases at 250°F. with and without the alkali metal aroate was determined. Without other additives, the lifetime went from 24 hours to 300 hours. In the presence of other additives, the lifetime went from 48 hours to 1,128 hours.

The test is carried out by heating a thin film of grease at a constant temperature until the grease structure is lost. During the test, the grease is subjected to evaporation, degradation and oxidation. Whatever effect the alkali metal aroate has, it greatly extends the lifetime of the grease structure.


It is interesting to note that every one of Ricketts' 14 claims is directed to the use of his additive "to prevent bleeding," no other result being mentioned in the claims


Appellant's brief gives us the following definition of "syneresis":

Loss of liquid lubricant from a lubricating grease due to shrinkage or rearrangement of the structure. The shrinkage may be due to either physical or chemical changes in the thickener. Syneresis is a form of BLEEDING.

He also defined "bleeding" thus:

The separation of liquid lubricant from a lubricating grease for any cause. (While excessive bleeding is harmful, a small amount of free oil can aid in lubrication).

Compare Gould's Medical Dictionary (5th Ed.) definition: "syneresis [* * * to draw together]. Contraction of a clot (blood, milk etc.)" and the Random House Dictionary (1967) definition: "syneresis * * * 2. Physical Chem. the contraction of a gel accompanied by the exudation of liquid." Appellant's definitions are said to be " [f]or the most part" taken from the "NLGI Spokesman, a respected journal in the lubricating grease field."