Application of John D. Sutherland, Jr

347 F.2d 1009, 52 C.C.P.A. 1683
CourtCourt of Customs and Patent Appeals
DecidedJuly 22, 1965
DocketPatent Appeal 7299
StatusPublished
Cited by13 cases

This text of 347 F.2d 1009 (Application of John D. Sutherland, Jr) is published on Counsel Stack Legal Research, covering Court of Customs and Patent Appeals primary law. Counsel Stack provides free access to over 12 million legal documents including statutes, case law, regulations, and constitutions.

Bluebook
Application of John D. Sutherland, Jr, 347 F.2d 1009, 52 C.C.P.A. 1683 (ccpa 1965).

Opinions

RICH, Judge.

This appeal is from the decision of the Patent Office Board of Appeals affirming the examiner’s rejection of claims 57-70 of application serial No. 679, 849, filed August 23, 1957, for “Treatment of Synthetic Rubber Latex.” Only claims 57-60 have been appealed.

There were two grounds of rejection of record, the first of which was double patenting over the claims of an application by Carpenter, now patent No. 2,993,020, assigned to the same assignee as the present application, Copolymer Rubber & Chemical Corporation, of Baton Rouge, Louisiana. This is the only rejection sustained by the board, the other rejection that the claims -are misdescriptive having been reversed.

The instant application and the Carpenter application were filed on the same day. They were prepared by the same attorneys for the same corporation and contain much common subject matter in their specifications. The drawings, a process flow-sheet, appear to be identical. Both applications relate to the process of “agglomerating” synthetic rubber latex, which we are admonished is not to be confused with “coagulation” of latex. The latter produces solid rubber from the liquid latex whereas the former has for its purpose an increase in the size of the minute particles of rubbery material suspended in liquid latex to give the latex more desirable properties. More specifically, in the making of foam rubber articles, for example, it is desirable to have a latex with a high total solids content but low viscosity. Whereas increasing solids content normally increases vis[1010]*1010cosity, this can be avoided by agglomerating the latex. Another matter of concern is the creation of “prefloc” during processing and storage, defined as being an irreversible coagulation which gums up the machinery and requires cleaning of it. Mechanical stability of the latex is also desired.

At the time both Sutherland and Carpenter, who apparently worked together, made their respective inventions, it appears that there was already known an agglomeration process which involved the steps of freezing and thawing. The following paragraph from appellant’s specification describes it and an almost identical paragraph appears in Carpenter’s patent:

One of the more satisfactory low temperature processes for the agglomeration of low solids synthetic rubber latex is one in which a specific low solids GR-S latex is agglomerated by reducing the pH with carbon dioxide and then subjecting the latex to a freezing action for a short period of time at a temperature only moderately below the apparent freezing point of the latex [+28°F.], such as at about 10°F. The agglomerated GR-S latex thus produced may be concentrated to produce a high solids latex of reasonable viscosity. If it is desired to further agglomerate the latex and to further improve the viscosity characteristics, the once frozen and thawed concentration latex is refrozen and reconcentrated.

In both the application and the patent there then follows another paragraph pointing out certain shortcomings in the known freeze-thaw process such as undesirably high viscosity, instability resulting in undesirable amounts of prefloc, and inability to uniformly control the viscosity.

From this background, again with much common disclosure, the application and the patent proceed to the description of two different inventions, each having as its ultimate objective improvement in the agglomeration process. Carpenter’s invention has to do with the blending of different latices in the agglomeration process and is thus explained succinctly in appellant’s brief:

Carpenter patent No. 2,993,020 discloses an improved process for enlarging the average particle size of synthetic rubber latex blends by steps including freezing and thawing. Carpenter’s inventive concept is entirely different from that of the appellant’s. Carpenter made the surprising discovery that a latex blend prepared from frozen and thawed agglomerated synthetic rubber latex having a relatively large average particle size and synthetic rubber latex having a relatively small average particle size exhibited enhanced mechanical stability characteristics. He also further discovered that when such a latex blend is frozen and thawed in the freeze-thaw agglomeration process, prefloc formation may be reduced very markedly. [Emphasis ours.]

With this statement in mind, now would be a good time to read claim 1 of Carpenter’s patent to see what invention is there being claimed, and how. Patent claims 1-4 are relied on to support the sole rejection on the ground of double patenting and it will suffice to consider claim 1, which reads:

1. In a process for enlarging the average particle size of synthetic rubber latex wherein the latex is agglomerated by steps including freezing and thawing in which prefloc is formed, the improvement which comprises reducing prefloc formation by freezing and thawing a synthetic rubber latex blend comprising frozen and thawed agglomerated synthetic rubber latex and synthetic rubber latex having a smaller average particle size than the frozen and thawed agglomerated latex, each 100 parts of the latex blend containing 5-85 parts of the frozen and thawed agglomerated latex and 95-15 parts of the latex having a smaller average particle size when calculated by [1011]*1011weight on a dry solids basis, the synthetic rubber latex being selected from latices of the group consisting of latices of rubbery homopolymers of conjugated diolefins and latices of rubbery copolymers of conjugated diolefins and monoethylenically unsaturated monomers. [Emphasis ours.]

Sutherland’s invention was based on a discovery with respect to the temperature used in freezing the latex in the old freeze-thaw agglomeration process. Apparently the art had taught that in such a process, to quote the application, “in order to prevent irreversible coagulation, the latex must be subcooled to a temperature only moderately below its freezing point, i. e., to a temperature only moderately below 28°F. It was further taught that temperatures as high as —6°F. always caused irreversible coagulation of the latex and thus were to be avoided.” The freezing in this known process, as well as in practicing either appellant’s or Carpenter’s inventions, takes place on a rotating drum through which coolant is circulated and which dips into a tank of latex, the frozen film being stripped after about half a revolution out of the bath by a doctor blade. The specification continues :

In accordance with these teachings, the freezer drum 65 was operated in such a manner that the collected latex film 70 was subcooled at the time of removal by scraper 71 to a temperature only moderately below the freezing point of the latex, such as about 10°F. Under these conditions it was extremely difficult to operate the freezer drum 65 and associated apparatus. For example, the collected latex film 70 was found to cling so tenaciously to the freezer drum surface 68 that excessive power requirements were necessary to drive the freezer drum 65. Also, the freezer drum 65 rotated with an uneven, jerking motion which caused the scraper 71 to gouge into the drum surface 68, as well as causing metal fatigue and eventual failure.

Appellant’s invention, in a nutshell, was the discovery that he could solve the foregoing problems, in defiance of the teaching of the art about temperatures, by subcooling to temperatures of —10 °F.

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Bluebook (online)
347 F.2d 1009, 52 C.C.P.A. 1683, Counsel Stack Legal Research, https://law.counselstack.com/opinion/application-of-john-d-sutherland-jr-ccpa-1965.