Appeal No. 1997-2072
Application No. 08/261,544
process. See, e.g., Rains, column 2, lines 8-68 and Nodelman,
column 2, lines 3-24. According to both Rains (column 1,
lines 13-48) and Nodelman (column 1, lines 7-32):
Reaction injection molding (RIM) has become an
important process for the manufacture of a wide
variety of moldings. The RIM process is a so-called
“one-shot” process which involves the intimate
mixing of a polyisocyanate component and an
isocyanate-reactive component followed by the
injection (generally under high pressure) of the
mixture into a mold with subsequent rapid curing.
The polyisocyanate component is generally a liquid
isocyanate. The isocyanate-reactive component
generally contains a high molecular weight
isocyanate-reactive component (generally a polyol),
and usually contains a chain extender or cross-
linker containing amine or hydroxyl groups.
U.S. Pat. No. 4,218,543 describes one particularly
commercially significant RIM system, which requires
the use of a specific type of aromatic amine as a
cross-linker/chain extender. The preferred amine
described in the ‘543 patent is diethyl toluene
diamine (DETDA). Formulations based on DETDA are
generally restricted to the lower flexural modulus
range (i.e., less than about 70,000 psi at room
temperatue [sic]). While it is known to use DETDA
in combination with other co-chain extenders in
order to increase the flexural modulus of the
resultant molding, the use of such co-chain extender
generally adversely affects the thermal properties
of the resultant part. 1
1Whether or not the disclosure of the ‘543 patent has a
bearing on the patentability of the appealed subject matter
has not been determined by this panel as the examiner has not
relied on said reference to reject the appealed claims.
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