In re Clemens

• Decision Date: 12 June 1980
• Docket Number: Appeal No. 79-595.
• Citation: 622 F.2d 1029
• Parties: In re David H. CLEMENS, Marvin J. Hurwitz, and Robert W. Walker.
• Court: U.S. Court of Customs and Patent Appeals (CCPA)

622 F.2d 1029

In re David H. CLEMENS, Marvin J. Hurwitz, and Robert W. Walker.

Appeal No. 79-595.

United States Court of Customs and Patent Appeals.

June 12, 1980.

John F. Witherspoon, Washington, D. C., attorney of record for appellant; Michael B. Fein, and Louis F. Kline, Jr., Philadelphia, Pa., of counsel.

Joseph F. Nakamura, Washington, D. C., for the Commissioner of Patents and Trademarks; Gerald H. Bjorge, Washington, D. C., of counsel.

Before MARKEY, Chief Judge, and RICH, BALDWIN, MILLER and MALETZ, Judges.^*

MALETZ, Judge.

This is an appeal from the decision of the United States Patent and Trademark Office (PTO) Board of Appeals (board) sustaining the examiner's rejection under 35 U.S.C. § 103 of claims 1-10 of application serial No. 641,464, filed December 17, 1975, a continuation-in-part of application serial No. 428,968, filed December 27, 1973, for "Method of Purifying Condensate Water for Steam Regenerating Equipment." We modify.

Background

Invention

Appellants' claimed process is for removing corrosion products from condensate waters in a steam regenerating system, i. e., a system in which steam, after passing through a steam turbine to generate electricity, is recycled as condensate to a boiler. This purification process, called condensate polishing, utilizes strong base ion exchange resins derived from crosslinked vinylbenzyl chloride, hereinafter referred to as VBC-based resins, to remove small amounts of dissolved solids from the condensate.

The following claims are before us on appeal:

1. A process for removing corrosion products from high pressure boiler condensate waters at elevated temperatures which comprises contacting the waters containing the corrosion products with a mass of crosslinked vinylbenzyl chloride strong base ion exchange resin, wherein the crosslinker is a polyvinyl compound.

2. A process as claimed in Claim 1 wherein the waters are passed through the resins at flow rates between 30-100 gal/min/sq. ft.

3. A process as claimed in Claim 1 wherein the corrosion products comprise dissolved metal hydroxides and hydrous oxides.

4. A process as claimed in Claim 2 wherein the corrosion products contain magnetite.

5. A process as claimed in Claim 1 wherein the resins are gellular instructure sic.

6. A process as claimed in Claim 1 wherein the resins are macroreticular in nature.

7. A process as claimed in Claim 1 which additionally includes a cation exchange step.

8. A process as claimed in Claim 1 wherein the boiler condensate waters are at a temperature in excess of 100°C when contacted with the strong base ion exchange resin.

9. A process as claimed in Claim 1 wherein the crosslinker is divinyl benzene.

10. A process as claimed in Claim 1 wherein the crosslinker is present in an amount of from about 1% to about 10% by weight of the resin.

Prior Art

The VBC-based resins used by appellants are very similar structurally to prior art resins, referred to as CME-based resins, which are derived from styrene-divinyl benzene polymers that have been chloromethylated with chloromethyl ether. The differences between the VBC-based resins and the CME-based resins result from the method of attaching the chloromethyl groups to the aromatic rings of their polymeric backbones. In preparing VBC-based resins, the polymer is formed from monomers which have the chloromethyl group already attached to the aromatic ring. On the other hand, in preparing CME-based resins, the polymer is formed first and the chloromethyl groups are added later. These differences in preparation are thought to result in differing degrees of secondary crosslinking in the polymer.

The PTO has cited the following four references: Rieman,¹ which describes VBC-based resins; Kun et al.² and Kressman et al.³ which disclose treatments of boiler feed waters with CME-based resins, and Otis,⁴ which allegedly equates boiler feed water treatments with condensate water treatments. We need not discuss these references further, however, since appellant has simplified the matter before us by acknowledging that the following are prior art:

(1) VBC-based resins per se;

(2) the use of VBC-based resins generally for ion exchange purposes;

(3) CME-based resins per se;

(4) the use of CME-based resins generally for ion exchange purposes; and

(5) the use of CME-based resins specifically for condensate polishing.

Notwithstanding this prior art, appellants claim that there was a serious drawback in the use of CME-based resins for condensate polishing. More specifically, appellants represent that in order to avoid the thermal degradation of these resins during condensate polishing, it was necessary to cool the hot condensate to below 60°C before treatment. This representation is substantiated by product brochures for CME-based resins which are sold by appellants' assignee. For these brochures specify that the maximum temperature at which the hydroxide form⁵ of these resins can be used is 140°F (60°C).

Barrett Reference

The PTO has also relied on a United States patent issued to Barrett.⁶ This patent has an earlier effective filing date than appellants' application. Also, the Barrett patent and appellants' application have a common assignee.

The Barrett patent describes a macroreticular polymer of crosslinked vinylbenzyl chloride which can be used to make VBC-based resins. The patent discloses and claims the polymer itself (claims 1-8), the process of making the polymer (claims 9-13), the process of making VBC-based resins from the polymer (claims 14-19), the VBC-based resins derived from the polymer (claim 20), and the process of using these VBC-based resins (claims 21 and 22). The process-of-using claims are drafted broadly, and set forth a process for removing a component from a liquid by treating the liquid with the claimed resin.⁷

The Barrett patent specifically mentions condensate polishing in the following paragraphs in the specification describing the prior art:

The polymers produced by such a prior art process are, after conversion, used to form ion exchange resins. Such known resins although satisfactory for many ion exchange utilizations have been criticized as being too fragile in certain fields of use. Areas of ion exchange resin use such as the removal of strong acids or weak acids from aqueous solution, as done in condensate polishing, nuclear loop water treatment or continuous ion exchange processes as practiced for example in sugar refineries, require resins which must possess long term resistance to degradation in functionality. Resistance to degradation during high temperature operating conditions is also important for good resin performance. Heretofore, a resin with a satisfactorily high column capacity was invariably too vulnerable physically for high stress operations such as the continuous ion exchange processes mentioned hereinbefore. Col. 1, lines 43-58 Emphasis added.

* * * * * *

Another resin characteristic important in determining durability of a resin is its ability to withstand thermal degradation. This characteristic is normally termed thermal stability. Anion exchange resins in the hydroxide form are particularly susceptible to thermal degradation. Their short effective life in use areas such as boiler steam condensate purification, where the hydroxide form is required and high temperatures prevail, contributes substantially to the cost of their operation. Col. 1, line 69—Col. 2, line 6 Emphasis added.

The Barrett disclosure also refers to tests run to compare the thermal stability of the claimed VBC-based resins with corresponding CME-based resins. Barrett sums up the results as follows: "The results indicate that VBC resins have consistently greater thermal stability than the corresponding CME resins." Supra n.6, col. 8, lines 6-8.

Rule 131 Declaration

In order to remove Barrett as a reference, appellants filed a declaration under 37 CFR 1.131.⁸ In the declaration, they described three studies conducted at their direction prior to the filing date of the Barrett patent. These studies were designed to investigate the relative ion exchange capacities and thermal stabilities of various VBC-and CME-based resins. Summary reports and laboratory notebook pages documenting these investigations were submitted. Appellants maintained that this showing effectively removed Barrett as a prior art reference under 35 U.S.C. § 103 by establishing that appellants made their invention prior to the filing date of the application which resulted in the Barrett patent.

Rebuttal Evidence

Two of the studies described in appellants' Rule 131 declaration were designed to compare the thermal stability of VBC-based resins used in the claimed process with closely-related CME-based resins used in prior art condensate polishing.

The results from these tests showed that at 110°C and 130°C the VBC-based resins were more thermally stable. In fact, at 110°C the VBC-based resins had 48% longer half-lives than their CME-based counterparts. Appellants argued that these results demonstrated an unexpected superiority of the claimed process.

Examiner's Rejections

Initially, the examiner made four separate rejections. First, claims 1-10 were rejected under 35 U.S.C. § 112 for being vague and indefinite. Second, claims 1-8 and 10 were rejected under 35 U.S.C. § 112 for being broader than the disclosure. Third, claims 1-6 and 8-10 were rejected under 35 U.S.C. § 103 for being obvious from Kun in view of Rieman and Otis with Kressman being additionally applied as to claim 7. This third rejection is hereafter referred to as the CME rejection. Fourth, claims 1-10 were rejected under 35 U.S.C. § 103 for being obvious from Barrett—a rejection which will be referred to hereafter as the Barrett rejection.

The rejections under 35 U.S.C. § 112 were ultimately withdrawn by the examiner but both the CME and Barrett rejections were maintained. In response to appellants' argument that the Barrett rejection was overcome by the Rule 131...