ALMOND, Judge.
This is an appeal from the affirmance by the Board of Appeals of the examiner’s rejection of appellants’ patent application.1
The invention relates to a method of coating paper with an aqueous composition containing a mineral pigment, an adhesive and a water repellent dimer of an aliphatic ketene. In discussing the prior art, the specification states:
“It has been known for many years to make mineral-coated printing paper by applying to the paper base, an aqueous suspension or slurry containing mineral pigment, such as clay or calcium carbonate, and which also contains water-dispersible binding material or adhesive, such as starch adhesive or casein. The dry weight of adhesive used in a coating composition generally is small in comparison to the weight of pigment in such coating composition, since ordinarily it is desired to use the smallest amount of adhesive which will bind the coating pigment securely to the paper base. Consequently the final layer of dry coating contains capillary pores into which ordinary aqueous ink and printing ink can easily penetrate.”
In addition it was found desirable to “size” the paper to make it water repellent. Ordinarily, according to the specification, sizing was accomplished by precipitating rosin with alum, but alum had several disadvantages. The specification notes:
“ * * * The purposes of the invention are accomplished by including in the aqueous mineral-coating composition, a sizing agent which has not hitherto been used in mineral-coating compositions.”
The sizing agents disclosed are dimers of aliphatic ketenes having hydrocarbon chains of from six to twenty carbon atoms. The ketene dimers are said to “migrate” from the coating to the underlying paper to render it water repellent.
Claim 12 is drawn to a process of applying the composition after preparing an unsized web and thereafter aging the [971]*971coated web. The remaining claims, 13 and 14, claim the resultant mineral coated paper.
Claim 12 reads:
“A process for sizing paper comprising the steps of: preparing a substantially unsized fibrous cellulose paper web, preparing an aqueous coating composition consisting essentially of a mineral pigment selected from the group consisting of clay, calcium carbonate, magnesium carbonate, talc, titanium dioxide, barium sulfate, zinc sulfide, satin-white and ochre, an adhesive binder for said pigment selected from the group consisting of starch, casein, soy protein, gelatin, animal glue, British gum, dextrin, polyvinyl alcohol, synthetic latex, and water soluble and alkali soluble cellulose esters, and between 0.25% to 4% by weight of total solids in said coating composition of a water repellent dimer of an aliphatic ketene having from 6 to 20 carbon atoms in its aliphatic hydro-carbon group; applying said coating composition to said web; and thereafter aging said coated web; whereby during said application said coating composition and the water therein penetrate the surface of said web, with said coating composition affixing itself firmly to said web, and said dimer thereafter and during said aging step migrates from said coating composition to the fibers of said sheet and sizes the same.”
The issue is whether the Board of Appeals erred in rejecting the claims as unpatentable over the prior art.
The examiner and the board relied on the following references:
Ruff 2,140,394 Dee. 13, 1938
Downey 2,627,477 Feb. 3, 1953
Keimetal. 2,762,270 Sept. 11, 1956
The Ruff patent discloses a method of coating paper with an aqueous composition of starch and a mineral pigment and an adhesive of starch or casein. The patent states:
* A starch alkaline material as prepared according to this invention may be mixed directly with a solution of casein; and may be sized with rosin and alum with practically no loss in sizing efficiency or excessive use of alum.” A “ * *
The Downey patent relates to a higher alkyl ketene dimer emulsion as a substitute for rosin in the sizing of paper. The ketene dimer is said to be reactive with the hydroxyl groups of the cellulose fibers. The Downey patent states:
“ * * * For the purpose of sizing paper, which is one of the ultimate processes to which the composition may be applied, the effectiveness of the emulsion as containing organic thickening agents such as, for example, starch, cellulose derivatives, or the like, is particularly surprising inasmuch as the ketene dimer which exhibits reactivity toward the carbohydrate cellulose molecule of the paper fibers is at the same time substantially unreactive both toward the hydroxyl groups of the aqueous medium and toward the hydroxyl groups of a carbohydrate thickening agent.”
The Downey patent refers to a eopend-ing application which matured into the Keim et al. patent. The latter patent discloses a process of sizing paper with a ketene dimer emulsion, “the new sizing agent being used in an amount astonishingly less than that needed with rosin and rosin substitutes.”
The examiner found that Downey “fully anticipates this claim [12] except for. the fact that it does not disclose the use’ of one of the applicant’s claimed nine' mineral pigments in the patentee’s aqueous sizing composition of starch and aliphatic ketene dimer,” and that “it would not be unobvious to merely add some clay or calcium carbonate to the sizing composition in Downey since it is conventional in the paper coating art to use mineral pigments as evidenced by Ruff, page 3, column 1, lines 10-27 and admitted by applicants in the specification, page 3, lines 7-11.”
[972]*972The board affirmed, stating:
“We find nothing unobvious for one skilled in the art in incorporating in the sizing composition containing the ketene dimer and starch of Downey, the pigment material of Ruff. Appellants urge that one skilled in the art would think that the pigment would absorb the ketene dimer. Since Downey, column 3, states that the ketene dimer is substantially unreactive toward the starch, from this it is not unexpected that the ketene dimer does not react with the pigment. Downey indicates that other substances, such as soaps, detergents, wetting and dispersing agents and the like can be included in his dimer sizing composition, which substances would necessarily cause more trouble with the action of the ketene dimer than would an inert pigment. Appellants have also urged that the aging step is critical. As the Examiner has pointed out, however, Keim et al. show this in sizing paper with a ketene dimer.”
Appellants contend that the term “sizing” is used in the specification as referring to a water repellent agent and that the disclosure of “a sizing agent” in the prior art does not necessarily mean that it is “a sizing agent of a type suitable for appellants’ purposes.” Another distinction urged is between “coating” of paper and “impregnating” of paper. Appellants argue that Downey and Keim et al. are concerned with paper sized by impregnating it with ketene dimer and not by coating. Although Ruff contemplates either coating a paper web or impregnating it, appellants submit that rosin size is used only with an impregnating process and not with a coating process.
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ALMOND, Judge.
This is an appeal from the affirmance by the Board of Appeals of the examiner’s rejection of appellants’ patent application.1
The invention relates to a method of coating paper with an aqueous composition containing a mineral pigment, an adhesive and a water repellent dimer of an aliphatic ketene. In discussing the prior art, the specification states:
“It has been known for many years to make mineral-coated printing paper by applying to the paper base, an aqueous suspension or slurry containing mineral pigment, such as clay or calcium carbonate, and which also contains water-dispersible binding material or adhesive, such as starch adhesive or casein. The dry weight of adhesive used in a coating composition generally is small in comparison to the weight of pigment in such coating composition, since ordinarily it is desired to use the smallest amount of adhesive which will bind the coating pigment securely to the paper base. Consequently the final layer of dry coating contains capillary pores into which ordinary aqueous ink and printing ink can easily penetrate.”
In addition it was found desirable to “size” the paper to make it water repellent. Ordinarily, according to the specification, sizing was accomplished by precipitating rosin with alum, but alum had several disadvantages. The specification notes:
“ * * * The purposes of the invention are accomplished by including in the aqueous mineral-coating composition, a sizing agent which has not hitherto been used in mineral-coating compositions.”
The sizing agents disclosed are dimers of aliphatic ketenes having hydrocarbon chains of from six to twenty carbon atoms. The ketene dimers are said to “migrate” from the coating to the underlying paper to render it water repellent.
Claim 12 is drawn to a process of applying the composition after preparing an unsized web and thereafter aging the [971]*971coated web. The remaining claims, 13 and 14, claim the resultant mineral coated paper.
Claim 12 reads:
“A process for sizing paper comprising the steps of: preparing a substantially unsized fibrous cellulose paper web, preparing an aqueous coating composition consisting essentially of a mineral pigment selected from the group consisting of clay, calcium carbonate, magnesium carbonate, talc, titanium dioxide, barium sulfate, zinc sulfide, satin-white and ochre, an adhesive binder for said pigment selected from the group consisting of starch, casein, soy protein, gelatin, animal glue, British gum, dextrin, polyvinyl alcohol, synthetic latex, and water soluble and alkali soluble cellulose esters, and between 0.25% to 4% by weight of total solids in said coating composition of a water repellent dimer of an aliphatic ketene having from 6 to 20 carbon atoms in its aliphatic hydro-carbon group; applying said coating composition to said web; and thereafter aging said coated web; whereby during said application said coating composition and the water therein penetrate the surface of said web, with said coating composition affixing itself firmly to said web, and said dimer thereafter and during said aging step migrates from said coating composition to the fibers of said sheet and sizes the same.”
The issue is whether the Board of Appeals erred in rejecting the claims as unpatentable over the prior art.
The examiner and the board relied on the following references:
Ruff 2,140,394 Dee. 13, 1938
Downey 2,627,477 Feb. 3, 1953
Keimetal. 2,762,270 Sept. 11, 1956
The Ruff patent discloses a method of coating paper with an aqueous composition of starch and a mineral pigment and an adhesive of starch or casein. The patent states:
* A starch alkaline material as prepared according to this invention may be mixed directly with a solution of casein; and may be sized with rosin and alum with practically no loss in sizing efficiency or excessive use of alum.” A “ * *
The Downey patent relates to a higher alkyl ketene dimer emulsion as a substitute for rosin in the sizing of paper. The ketene dimer is said to be reactive with the hydroxyl groups of the cellulose fibers. The Downey patent states:
“ * * * For the purpose of sizing paper, which is one of the ultimate processes to which the composition may be applied, the effectiveness of the emulsion as containing organic thickening agents such as, for example, starch, cellulose derivatives, or the like, is particularly surprising inasmuch as the ketene dimer which exhibits reactivity toward the carbohydrate cellulose molecule of the paper fibers is at the same time substantially unreactive both toward the hydroxyl groups of the aqueous medium and toward the hydroxyl groups of a carbohydrate thickening agent.”
The Downey patent refers to a eopend-ing application which matured into the Keim et al. patent. The latter patent discloses a process of sizing paper with a ketene dimer emulsion, “the new sizing agent being used in an amount astonishingly less than that needed with rosin and rosin substitutes.”
The examiner found that Downey “fully anticipates this claim [12] except for. the fact that it does not disclose the use’ of one of the applicant’s claimed nine' mineral pigments in the patentee’s aqueous sizing composition of starch and aliphatic ketene dimer,” and that “it would not be unobvious to merely add some clay or calcium carbonate to the sizing composition in Downey since it is conventional in the paper coating art to use mineral pigments as evidenced by Ruff, page 3, column 1, lines 10-27 and admitted by applicants in the specification, page 3, lines 7-11.”
[972]*972The board affirmed, stating:
“We find nothing unobvious for one skilled in the art in incorporating in the sizing composition containing the ketene dimer and starch of Downey, the pigment material of Ruff. Appellants urge that one skilled in the art would think that the pigment would absorb the ketene dimer. Since Downey, column 3, states that the ketene dimer is substantially unreactive toward the starch, from this it is not unexpected that the ketene dimer does not react with the pigment. Downey indicates that other substances, such as soaps, detergents, wetting and dispersing agents and the like can be included in his dimer sizing composition, which substances would necessarily cause more trouble with the action of the ketene dimer than would an inert pigment. Appellants have also urged that the aging step is critical. As the Examiner has pointed out, however, Keim et al. show this in sizing paper with a ketene dimer.”
Appellants contend that the term “sizing” is used in the specification as referring to a water repellent agent and that the disclosure of “a sizing agent” in the prior art does not necessarily mean that it is “a sizing agent of a type suitable for appellants’ purposes.” Another distinction urged is between “coating” of paper and “impregnating” of paper. Appellants argue that Downey and Keim et al. are concerned with paper sized by impregnating it with ketene dimer and not by coating. Although Ruff contemplates either coating a paper web or impregnating it, appellants submit that rosin size is used only with an impregnating process and not with a coating process. It is argued that adding mineral pigment to the Downey composition does not change the impregnating composition into a coating composition; that it would be expected that the mineral pigment would prevent the ketene dimer from “migrating” into the paper; that combining ketene dimer with a coating composition is unobvious in the absence of knowledge of the extraordinary migrating ability of the ketene dimer; that the prior art did not appreciate the migrating ability of the ketene dimer; and that it is unobvious to age the coated paper.
We agree with the solicitor that it would be obvious to substitute the ketene dimer sizing agent of Downey or Keim et al. for the rosin sizing agent in the aqueous compositions of mineral pigment and starch disclosed in Ruff.
Whatever definitions have been given to the term “sizing agent” in the art, it seems clear that Downey and Keim et al. use the term in the same manner as appellants for the same purpose and for the same material, viz. ketene dimer. The Keim et al. reference specifically suggests substituting ketene dimer for rosin or rosin substitutes in sizing paper. Even a narrow definition of “sizing agent” cannot avoid the fact that the same ketene dimers used by appellants, by any name, are disclosed in the prior art for sizing paper.
We have difficulty accepting the distinction urged by appellants that “coating” differs from “impregnating” in this case. It would appear that a porous material like paper would be impregnated to some extent by an aqueous composition applied “by various coating techniques” as Keim et al. suggests, whether the composition is called “coating” or “impregnating.” It seems doubtful that a clearly defined interface between the paper and the coating would result. The differences between coating compositions and impregnating compositions, according to appellants, are in dilution and viscosity. That is, a “coating composition usually has a high-solids content and a relatively high viscosity.” It is clear that none of the claims have any limitations on dilution (solids content) or viscosity. The method claim merely recites “applying” the composition which would appear to include both “coating” processes and “impregnating” processes, even if there is a distinction between “coating” and “impregnating,” and there is no evidence that the art recognizes a distinction. Ac[973]*973cordingly, we see no justification for con-eluding that it is unobvious to employ a sizing agent in either a “coating” composition or an “impregnating” composition.
We also see no reason for expecting that mineral pigment should prevent the ketene dimer from sizing the paper. Downey states that the ketene dimer is unreactive towards other ingredients of the sizing composition there disclosed, although it is reactive toward the paper fibers. One skilled in the art would hardly expect the inert clay or other mineral pigment to reduce the effectiveness of the Downey ketene dimer in reacting with cellulose paper fibers. While some of a very thick coating composition would be expected to stay on the surface of even a porous paper, we find nothing unob-vious in the fact that some of the ketene dimer reacts with the paper fibers to render them water repellent in view of the Downey disclosure. We note that appellant states that “some of the ketene dimer remains with” the coating. Since only minute amounts of the ketene dimer are used in the first place, and the claims fail to indicate what proportion goes into the fibers, there appears to be nothing which would not be obvious to one of ordinary skill in the art. Since Downey teaches that the ketene dimer will not react with anything present in the coating composition, yet will react with the paper, it seems entirely within the realm of the expected that appellants composition, containing in addition an inert mineral pigment, behaves in the same fashion as e owney composi ion.
The Keim_ et al. patent specifically states that sizing of the treated paper improves on standing after application of the ketene dimer. We think this is a clear suggestion of the claimed “aging” step and that one working in the art would find it obvious to age the ketene dimer treated paper.
We do not consider it unobvious to combine a ketene dimer sizing agent with a coating composition because the Ruff patent shows that other sizing agents (which ketene dimers were intended to replace) were used in coating compositions. Even if the “migrating ability” is “extraordinary” as alleged by appellants, the claims before us fail to define subject matter which, when considered as a whole, would not be obvious to a person having ordinary skill in the art.
Accordingly, the decision of the board js affirmed,
Affirmed