Appeal No. 2001-0676
Application No. 08/941,132
. . .
An additional disadvantage of natural rubber resides
in that it is colored and the coloration becomes more
conspicuous with the lapse of time, since it contains
carotenoid which is a polyene having an isoprene
structural unit and a number of conjugated double bonds.
However, these carotenoid impurities are eliminated
during the process for reducing proteins. Consequently,
a natural rubber comparable to synthetic ones in the
transparent and colorless appearance can be obtained.
Recognizing that Yasuyuki is silent as to graft-copolymerizing
or epoxidizing the deproteinized natural rubber, the examiner
relies on either Kondo, Burlett or Hayashi.
Kondo teaches graft-polymerizing a rubbery polymer, such as
synthetic rubber or natural rubber, which may be employed in the
form of a latex, to improve its physical properties, such as high
impact resistance and “beautiful appearance”. See column 2, line
61 to column 3, line 49 and column 4, lines 24-28. The appellants
also acknowledge that graft copolymerizing natural rubber to
improve its mechanical properties is known. See the specification,
page 2.
Given the improvement in physical properties imparted by
deproteinizing natural rubber (which is superior to synthetic
rubber in green strength) and graft-polymerizing protein free
(synthetic rubber) and protein present (natural rubber) rubbers, we
concur with the examiner that the combined teachings of Yasuyuki
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