WORLEY, Chief Judge.
This appeal is from a decision of the Board of Appeals affirming the rejection of claims 1-12 in appellants’ application1 for “Fire-Retardant Composition Derived from Tetrabromophthalic Acid Anhydride,” as “unpatentable” in view of certain prior art.
The subject matter is reflected in claims 1 and 6:
1. A method of preparing polyester resins that have fire-retardant characteristics when cured, which comprises: preparing a mixture of glycol and a component of the group consisting of saturated diearboxylic acids and anhydrides thereof, said component containing at least 10 mol percent of tetrabromophthalic acid an-hydride that has not above about 5 ppm. of ferric iron impurity associated therewith, and heating said mixture to form a polyester therefrom.
6. A polyester resin that has fire-retardant characteristics when cured, which comprises the reaction product of glycol and a component of the group consisting of saturated diearboxylic acids and anhydrides thereof that contain at least 10 mol percent of tetrabromophthalic acid anhydride that has not above about 5 ppm. of ferric iron impurity associated therewith.
The feature of the claims asserted to be nonobvious is the use of at least 10 mol percent of tetrabromophthalic acid anhydride (TBPAA) that has not more than 5 parts/million (ppm) ferric iron impurity as the acid component of a fire-retardant polyester resin.
The references are:
Lundberg 2,819,247 January 7, 1958.
Phillips et al. 2,921,925 January 19, 1960.
O’Neill 2,899,466 August H, 1959.
Tate 3,047,621 July 31, 1962.
Hoffman 3,007,943 November 7, 1961.
Wismer et al. 3,060,146 October 23, 1962.
Bjorksten, Polyesters and Their Application, pub. 1956, Reinhold Publishing Corp., New York, N. Y., page 160.2
A detailed discussion of the Lundberg, Phillips and Wismer references is unnecessary, since appellants admit that the art, as represented by those references, [665]*665knew that TBPAA “could be used in the preparation of polyesters with fire-retardant properties.”
Mindful of a similar concession below, the board sustained the examiner’s rejection of the claims as “unpatentable over” Lundberg alone or considered with Phillips. With respect to the limitation in the claims calling for not more than about 5 ppm of ferric impurity, the board stated:
* * * One skilled in this art would not be expected to employ an impure reactant, but would follow normal chemical practice and use a pure phthalic anhydride in the esterification. Since the references are silent as to any content of ferric ion it cannot be presumed that such ion is necessarily present in the starting material. * * * We therefore agree with the Examiner that a pure or iron-free reactant would normally be employed, thus rendering obvious appellants’ contribution.
We also note there to be no evidence in this record that all commercially available tetrabromophthalic anhydride would necessarily contain ferric ion in a proportion above the 5 ppm which appellants consider to be the operative limit of their contribution. The use of commercially available tetrabromophthalic anhydride having a low iron content is equally obvious in the polyesterifications of the prior art as the high iron content urged by appellants.
The board found it to be apparent from the background references cited by the examiner that purified phthalic acids would normally be employed by one of ordinary skill in the art in various esterification reactions. O’Neill, for example, discloses the desirability of removing colored impurities in terephthalic acid prior to using it in the manufacture of polyester fibers and films in order to obtain a product having good col- or. Tate removes certain impurities from various phythalic acids prior to preparing polyesters therefrom in order to improve the speed of the esterification reaction as well as the color, crystallinity and melting point of the ultimate polyester. Hoffman discloses that crystalline tetrachlorophthalic acid anhydride 3 “must be thoroughly purified” before it may be used for industrial purposes, and details a process for the removal of ferric iron and other impurities therefrom to obtain a product with the degree of purity required for use in the plastics and dye industries.
While appellants concede that those in the art were aware that TBPAA could be used in the preparation of polyesters with fire-retardant properties, they contend that there was a practical industrial problem which made it difficult to prepare polyesters from commercially available TBPAA. Appellants urge 'that their contribution resides in the “triple-faceted discovery” that: (1) the cause of the difficulty in processes for preparing polyesters with TBPAA resides in the presence of ferric iron in impure TBPAA; (2) the remedy resides in the use of TBPAA containing not more than 5 ppm ferric impurity in the esterification process; and (3) when TBPAA of such purity is used, fire-retardant properties far in excess of expectation are achieved in the products of the process.
We find no reversible error in the manner in which the examiner and board employed the primary and background references as evidence of the obviousness of the claimed subject matter. While such secondary considerations as “long felt but unsolved needs, [and] failure of others” are to be given effect in determining obviousness or nonobviousness under § 103,4 it is not clear from the evidence in the record here that the industrial problem of which appellants speak in fact existed, or that skilled workers knowledgeable in the art had failed to find any solution to the prob[666]*666lem. See In re Allen, 324 F.2d 993, 997, 51 CCPA 809, 813-814. Indeed, the one tangible, extraneous piece of evidence appellants cite in their specification in an effort to show that a problem did exist 5 is in marked contrast with the later disclosures of Phillips and Wismer, who speak matter-of-factly of the use of TBPAA in forming polyesters as if no problem existed at all.
In further support of their arguments, appellants point to Example II (particularly Table 1) and Example V of their application. We do not think those examples support appellants’ assertions of nonobviousness of the process and composition claims. With respect to the professed criticality of the use of TBPAA containing the claimed ferric ion content to facilitate an allegedly difficult esterification reaction, it is true that Example V of the specification states that “No polyester could be produced” when a sample of “commercial” grade TBPAA, containing 34 ppm ferric impurity, was employed in the esterification process, while the use of “purified” TBPAA containing 1.2 to 5 ppm of ferric iron “consistently produced polyesters.” However, the specification also states that “technical” grade TBPAA, said in Example III to be prepared by “the- conventional method wherein phthalic acid anhydride is brominated in the presence of oleum” and to contain 8 ppm ferric impurity, “did not consistently
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WORLEY, Chief Judge.
This appeal is from a decision of the Board of Appeals affirming the rejection of claims 1-12 in appellants’ application1 for “Fire-Retardant Composition Derived from Tetrabromophthalic Acid Anhydride,” as “unpatentable” in view of certain prior art.
The subject matter is reflected in claims 1 and 6:
1. A method of preparing polyester resins that have fire-retardant characteristics when cured, which comprises: preparing a mixture of glycol and a component of the group consisting of saturated diearboxylic acids and anhydrides thereof, said component containing at least 10 mol percent of tetrabromophthalic acid an-hydride that has not above about 5 ppm. of ferric iron impurity associated therewith, and heating said mixture to form a polyester therefrom.
6. A polyester resin that has fire-retardant characteristics when cured, which comprises the reaction product of glycol and a component of the group consisting of saturated diearboxylic acids and anhydrides thereof that contain at least 10 mol percent of tetrabromophthalic acid anhydride that has not above about 5 ppm. of ferric iron impurity associated therewith.
The feature of the claims asserted to be nonobvious is the use of at least 10 mol percent of tetrabromophthalic acid anhydride (TBPAA) that has not more than 5 parts/million (ppm) ferric iron impurity as the acid component of a fire-retardant polyester resin.
The references are:
Lundberg 2,819,247 January 7, 1958.
Phillips et al. 2,921,925 January 19, 1960.
O’Neill 2,899,466 August H, 1959.
Tate 3,047,621 July 31, 1962.
Hoffman 3,007,943 November 7, 1961.
Wismer et al. 3,060,146 October 23, 1962.
Bjorksten, Polyesters and Their Application, pub. 1956, Reinhold Publishing Corp., New York, N. Y., page 160.2
A detailed discussion of the Lundberg, Phillips and Wismer references is unnecessary, since appellants admit that the art, as represented by those references, [665]*665knew that TBPAA “could be used in the preparation of polyesters with fire-retardant properties.”
Mindful of a similar concession below, the board sustained the examiner’s rejection of the claims as “unpatentable over” Lundberg alone or considered with Phillips. With respect to the limitation in the claims calling for not more than about 5 ppm of ferric impurity, the board stated:
* * * One skilled in this art would not be expected to employ an impure reactant, but would follow normal chemical practice and use a pure phthalic anhydride in the esterification. Since the references are silent as to any content of ferric ion it cannot be presumed that such ion is necessarily present in the starting material. * * * We therefore agree with the Examiner that a pure or iron-free reactant would normally be employed, thus rendering obvious appellants’ contribution.
We also note there to be no evidence in this record that all commercially available tetrabromophthalic anhydride would necessarily contain ferric ion in a proportion above the 5 ppm which appellants consider to be the operative limit of their contribution. The use of commercially available tetrabromophthalic anhydride having a low iron content is equally obvious in the polyesterifications of the prior art as the high iron content urged by appellants.
The board found it to be apparent from the background references cited by the examiner that purified phthalic acids would normally be employed by one of ordinary skill in the art in various esterification reactions. O’Neill, for example, discloses the desirability of removing colored impurities in terephthalic acid prior to using it in the manufacture of polyester fibers and films in order to obtain a product having good col- or. Tate removes certain impurities from various phythalic acids prior to preparing polyesters therefrom in order to improve the speed of the esterification reaction as well as the color, crystallinity and melting point of the ultimate polyester. Hoffman discloses that crystalline tetrachlorophthalic acid anhydride 3 “must be thoroughly purified” before it may be used for industrial purposes, and details a process for the removal of ferric iron and other impurities therefrom to obtain a product with the degree of purity required for use in the plastics and dye industries.
While appellants concede that those in the art were aware that TBPAA could be used in the preparation of polyesters with fire-retardant properties, they contend that there was a practical industrial problem which made it difficult to prepare polyesters from commercially available TBPAA. Appellants urge 'that their contribution resides in the “triple-faceted discovery” that: (1) the cause of the difficulty in processes for preparing polyesters with TBPAA resides in the presence of ferric iron in impure TBPAA; (2) the remedy resides in the use of TBPAA containing not more than 5 ppm ferric impurity in the esterification process; and (3) when TBPAA of such purity is used, fire-retardant properties far in excess of expectation are achieved in the products of the process.
We find no reversible error in the manner in which the examiner and board employed the primary and background references as evidence of the obviousness of the claimed subject matter. While such secondary considerations as “long felt but unsolved needs, [and] failure of others” are to be given effect in determining obviousness or nonobviousness under § 103,4 it is not clear from the evidence in the record here that the industrial problem of which appellants speak in fact existed, or that skilled workers knowledgeable in the art had failed to find any solution to the prob[666]*666lem. See In re Allen, 324 F.2d 993, 997, 51 CCPA 809, 813-814. Indeed, the one tangible, extraneous piece of evidence appellants cite in their specification in an effort to show that a problem did exist 5 is in marked contrast with the later disclosures of Phillips and Wismer, who speak matter-of-factly of the use of TBPAA in forming polyesters as if no problem existed at all.
In further support of their arguments, appellants point to Example II (particularly Table 1) and Example V of their application. We do not think those examples support appellants’ assertions of nonobviousness of the process and composition claims. With respect to the professed criticality of the use of TBPAA containing the claimed ferric ion content to facilitate an allegedly difficult esterification reaction, it is true that Example V of the specification states that “No polyester could be produced” when a sample of “commercial” grade TBPAA, containing 34 ppm ferric impurity, was employed in the esterification process, while the use of “purified” TBPAA containing 1.2 to 5 ppm of ferric iron “consistently produced polyesters.” However, the specification also states that “technical” grade TBPAA, said in Example III to be prepared by “the- conventional method wherein phthalic acid anhydride is brominated in the presence of oleum” and to contain 8 ppm ferric impurity, “did not consistently produce polyesters” when used in the esterification process. (Emphasis supplied). The record contains no data to further elucidate what the expression “did not consistently” means in the present context. It seems apparent that the phrase is broad enough to allow production of polyesters from “technical” grade TBPAA containing 8 ppm ferric impurity as infrequently as 1 out of a 100 times, or, for that matter, as frequently as 99 out of a 100 times. We do not think the equivocal, relative language employed by appellants establishes that a problem necessarily existed with respect to the use of the “technical” grade TBPAA of the prior art or the criticality of the claimed ferric' iron content they allege here.
Insofar as the efficacy of Example II of the application to show nonobviousness of the claimed polyester composition is concerned, it should be noted that appellants have only shown that resins produced from TBPAA containing less than 5 ppm ferric impurity have superior fire-retardant properties vis-avis resins produced from other phthalic acids, subject matter not relied on by the Patent Office in the rejection. There is no comparison of the fire-retardant properties of the claimed resin with like properties of a resin produced from TBPAA containing slightly more than 5 ppm ferric impurity.
While we appreciate appellants’ arguments, we are satisfied the board committed no reversible error in sustaining the rejection.
The decision is affirmed.
Affirmed.