Appeal No. 95-3976
Application 08/164,733
star polymer as a “solid crumb”; and (iii) blending the star polymer with a base oil. The claimed process
further limits the average molecular weight of polyisoprene to between 30,000 and 60,000 and the average
molecular weight of polystyrene to be from 3,000 to 4,000. The core of the star polymer is the
polyalkylene coupling agent while the polymeric arms of the star are formed by the poly(isoprene/styrene)
block copolymer.
The examiner determined that the claimed process was anticipated by Example 13 of Eckert under
35 U.S.C. § 102(b). Eckert discloses preparing a living poly(isoprene/styrene) block copolymer wherein
the average molecular weight of polyisoprene is 41,000 and the average molecular weight of polystyrene
is 4,000. The examiner found that all elements of the claimed invention were disclosed by Eckert except2
for forming a “solid crumb.” The examiner held that the recovery of the star polymer as a “solid crumb”
would be inherent from the teachings of Eckert. Appellants argue that Example 13 of Eckert describes a
star polymer having the styrene blocks next to the core of the star polymers (i.e. at the inner end of the
polymeric arms) whereas the claimed composition requires the styrene blocks to be away from the core
at the outer end of the polymeric arms. Appellants further argue that “Eckert at best suggests recovering
polymers having small terminal styrene blocks as a solid crumb and Applicants are not aware of precedent
holding that patentability can be denied based upon the inherent result of a suggested invention” (reply brief:
The example does not explicitly disclose the average molecular weight for polystyrene, but it does disclose2
the average molecular weight of polyisoprene as being 41,000 and the average molecular weight of the
polyisoprene/polystyrene block copolymer as being 45,000. It is reasonable to presume that the difference (45,000 -
41,000) would be the molecular weight of polystyrene in the block copolymer.
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