Appeal No. 1997-4318
Application 08/469,806
percent (col. 4, lines 58-60) for the purposes of calcining particles containing anhydrous mineral pigment
particles, none of which comprise iron, chromium, manganese or titanium oxides (e.g., col. 2, lines 22-
62). Caswell would have disclosed that “colloidal silica” can be a binding agent in similar manner to
“film-forming organic binders” and “various industrial gums, rubber latex, resins, starch, asphalt, coal
and tar” in forming clay agglomerates, none of which are disclosed in Jungk. Sams teaches that
hydrated, soluble alkali metal silicate can be used, inter alia, in “brick manufacture,” but there is no
disclosure of a pigment. We find that the remaining references add little additional specific teachings to
this record with respect to that which is known about alkali metal silicates as a binder for other
purposes.
On this record, we cannot agree with the examiner that, prima facie, the combined teachings of
these diverse references would have reasonably suggested to one of ordinary skill in this art, armed with
the knowledge of the use of, inter alia, titanium dioxide and red iron oxides as pigments for colouring
concrete, that such pigments, substantially free of organic liquefiers, can be combined with a binder,
such as sodium silicate, in an amount to obtain microgranulates that break down and disperse in
concrete when the particles have a particular average particle size, as specified in claims 13 and 26.
See, e.g., Gorman, supra; Keller, supra. We find that 3M GB ‘259 constitutes the closest prior art
with respect to the claimed microgranulate pigments of claim 26, and also with respect to the
microgranulate pigments used in the process of colouring cement in claim 13. We agree with appellants
(brief, page 12) that there is a significant difference between the claimed and reference pigment particles
in the amount of the silicate employed. We find that the examiner has not provided an explanation why
one of ordinary skill in this art would have modified the amount of silicate taught by 3M GB ‘259 in the
context of using such a modified pigment particle for the purposes disclosed in this reference, separately
or as combined with any other reference (see answer, pages 10-11). Indeed, as we found above, the
examiner does not explain why one of ordinary skill in this art would have used any particular amount of
sodium silicate as a binder based on the range of amounts of organic liquefiers disclosed by Jungk.
In this respect, we observe that the prior merits panel of this board found in Appeal No. 93-
3107 that the pigment particles of 3M GB ‘259 “would obviously meet the needs of the pigment
microgranules disclosed by Jungk prepared in essentially the same manner, especially in view of the
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