Application of Hellsund

• Decision Date: 15 March 1973
• Docket Number: Patent Appeal No. 8607.
• Citation: 474 F.2d 1307,177 USPQ 170
• Parties: Application of Olof H. HELLSUND.
• Court: U.S. Court of Customs and Patent Appeals (CCPA)

177 USPQ 170, 474 F.2d 1307 (1973)

Application of Olof H. HELLSUND.

Patent Appeal No. 8607.

United States Court of Customs and Patent Appeals.

March 15, 1973.

Richard E. Lyon, James W. Geriak, Thomas D. Kiley, Los Angeles, Cal., Francis D. Thomas, Jr., Washington, D. C., Lyon & Lyon, Los Angeles, Cal., attorneys of record, for appellant.

S. Wm. Cochran, Washington, D. C., for the Commissioner of Patents. Raymond E. Martin, Washington, D. C., of counsel.

Before RICH, Acting Chief Judge, ALMOND, BALDWIN and LANE, Judges, and RAO, Judge, United States Customs Court, sitting by designation.

ALMOND, Judge.

This is an appeal from the decision of the Patent Office Board of Appeals affirming the rejection of claims 1, 2, 4, 7-10, and 21-23 of appellant's application entitled "Continuous Casting Process and Apparatus."¹ No claims were allowed.

The invention relates to the continuous casting of polymers into sheets. Appellant's apparatus can best be understood with reference to Figs. 1a, 1b and 2, reproduced below:

Appellant casts polymeric sheets by feeding a monomer between two moving endless belts and curing (polymerizing) the monomer while it is contained within the space between the belts. Liquid monomer is fed to the top of lower belt 12 at point 18. The monomer is carried between rollers 13 and 16, at which point it becomes enclosed between the lower run of upper belt 11 and the upper run of lower belt 12. The two belts move through the curing zone 29 at the same speed. Curing is effected by heating the monomer, preferably by spraying belts 11 and 12 with hot liquid. The liquid, such as water, is sprayed from nozzles 33 which are positioned above and below the monomer as shown in Fig. 2. The polymer sheet may be postcured in zone 30. Belts 11 and 12 are supported at the desired distance from each other by rolls, such as rolls 37 and 38 in Fig. 2, which are spaced at short distances throughout the curing and postcuring zones.

As can be seen from the drawings, belts 11 and 12 follow a downward inclined path from the point defined by rolls 13 and 16 until they reach postcuring zone 30. The path is inclined in order to avoid problems previously encountered in polymer casting. It appears that continuous polymer casting between horizontal endless belts had previously been known, but that it had been impossible to maintain the spacing between the belts. This resulted in the lack of control over the thickness of the product. This problem was overcome by running the belts at an angle to the horizontal for the length of the curing zone so that a pressure head of the liquid monomer is developed which is sufficient to maintain the spacing between the belts until the liquid is polymerized. Appellant did not discover the use of the inclined path to maintain the spacing between the belts. Appellant's contribution resides in the suggestion that while the belts are inclined they should follow a curved path which is defined by their own natural curvature.

Claim 1 is illustrative:

1. A process for preparing substantially rigid sheets and the like which comprises passing a fluid composition comprising a polymerizable organic monomer between and in contact with two moving surfaces, providing a pair of seals between said surfaces such that said fluid composition is confined in a space bounded on two opposing sides by said seals, allowing said fluid to fill the cavity defined by said surfaces and said seals, passing said composition and moving surfaces through at least one zone in which said composition is subjected to conditions which cause said monomer to polymerize, one of said surfaces being disposed above the other of said surfaces in said zone, said upper surface being of such a size and weight that it would bow downwardly into said fluid and toward said second surface if said surfaces were horizontal in said zone, the path of said surfaces through said zone being defined by the natural curvature of said moving surfaces and maintaining said surfaces at an incline to the horizontal in said zone to cause a fluid head to be developed by said fluid composition whereby the fluid pressure exerted by said fluid composition is sufficient to maintain said surfaces substantially parallel to each other and the spacing between said surfaces at a predetermined distance in said zone, said natural curvature being substantially that which said surfaces would assume if supported only at the upper and lower limits of said incline, bringing said surfaces together to an extent sufficient to compensate for any shrinkage of the composition during polymerization such that said surfaces are maintained in contact with said composition during polymerization, and removing the resultant polymerized sheet from both of said surfaces.

The other claims add limitations concerning the monomer used, specify that the moving surfaces are made of stainless steel, add a postcuring step, or differ from claim 1 in other respects not pertinent here. No distinction between the claims has been drawn, and accordingly they will stand or fall together.

The rejection of the claims was made on the basis of a patent to Opel et al. (Opel).² It is clear from the patent that it was Opel who solved the problems associated with horizontal belt continuous casting by arranging the endless belts so that they are "inclined in such a manner that the pressure of the materials between the belts is sufficient to maintain the spacing between them at a desired predetermined distance." The Opel patent refers to the present application, treating appellant's "natural curve" process as a specie of the generic invention of placing the belts at an incline:

As claimed herein, the inclined path of the moving belts may be a straight line or, as claimed in copending application Ser. No. 490,897, filed on the same date as the present application in the name of Hellsund, and assigned to the assignee of the present application, these belts may follow a curved path which is defined by the natural curvature of the belts.

The patent further states:

It is to be understood that the word "inclined" as used in the present specification and claims is intended to include straight, curved, angular or other paths which may be defined by a belt moving between a first roller and a second roller wherein the first roller is at a height greater than that of the second roller.

Figures 1a, 1b, and 2-5 of the Opel patent are essentially identical with Figs. 1a, 1b, and 2-5 of the present application, and the description of the apparatus depicted in those figures is correspondingly similar. The patent also contains Figs. 6 and 7, which are directed to the straight line inclined path process apparently invented by Opel.

Appellant does not contend that he invented the straight line or generic variation of the process. On the contrary, appellant's application specifically states:

However, it was not until the process and apparatus described and claimed in copending application Serial No. 490,945, now the Opel patent, filed on the same date as the present application in the names of Opel et al and assigned to the same assignee as the present application was developed that continuous casting of monomers on a commercial scale became possible. Certain problems continued to be experienced with regard to the use of the Opel et al process and apparatus including the need for extremely tall buildings to house the inclined portion of an apparatus of substantial length and the difficulty in maintaining the inclined portion in the desired position. Furthermore, the inclined portion of the Opel et al apparatus required rather massive supporting structures, and it was desired to simplify this portion of the apparatus.

The examiner rejected the claims under both section 102 and section 103 of the statute. The section 102 rejection, based on the premise that some "natural sag" would occur in even the straight line inclined path embodiment of Opel, was not sustained by the board.

Appellant argued before the board that the section 103 rejection should be reversed on two grounds: (1) that the Opel disclosure was not prior art with respect to appellant's application since they were both filed on the same day; and (2) that even if the Opel disclosure were available as prior art, appellant's invention would not have been obvious to one of ordinary skill in the art in view of the Opel disclosure. In his Answer, the examiner contended that appellant had admitted that the Opel invention was prior to his invention, pointing to the statements in appellant's application quoted above and also referring to statements allegedly made at an interview. The examiner postulated that the Opel disclosure was available as prior art under 35 U.S.C. § 102(a), (f) or (g).

Appellant submitted a brief in reply to the examiner's Answer. Whether or not appellant had previously admitted that part of the disclosure of the Opel patent was available as prior art, such an admission was clearly made in that reply brief. The pertinent portions of the reply brief are set forth below, with almost all emphasis being ours:

It is pointed out that the disclosure of Patent No. 3,376,371 is not available in its entirety, but only insofar as the disclosure therein is acknowledged as prior art in the present application. Indeed, it is expressly pointed out at column 2, lines 66-70 of Patent No. 3,376,371 that the embodiment comprising the use of curved belts is not the invention of the patentees but rather the invention of Hellsund, the applicant here. The Examiner appears to recognize this distinction at pages 6 and 7 of the Examiner\'s Answer, but goes on to find that it is "obvious" because:

1. Natural curvature is known; and

2. "It is not an unobvious result that continuous casting through a curved path is as feasible as continuous casting through a straight inclined path".

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Furthermore, the acknowledged prior art represented by part of the

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