Appeal No. 2002-0865
Application No. 08/940,996
a) in a first stage water is added as a solvent which is inert
in the reaction, and dispersing auxiliaries, seed and a first
portion of monomer(s) are added if desired,
b) in a second stage initiator is added, and
c) in a third stage the remainder or all of the monomer(s) is
added directly or in emulsion form and in the presence of further
water and, if desired, further dispersing auxiliary or other
auxiliaries,
it also being possible to operate the stages a) and b) or b) and
c) as a single stage, and
wherein the process further comprises
in at least one of stages a) to c), moving the reaction
mixture in its dispersion form by means of an external circuit
which leads from and back to the reaction vessel and comprises at
least one low-shear pump selected from the group consisting of
nonclogging pumps which operate in accordance with the vortex
principle, displacement pumps, monopumps and disc flow pumps and
at least one heat exchanger having an essentially laminar flow
profile, and
carrying out polymerization at from 40 to 120°C.
The examiner relies upon the following references as
evidence of obviousness:
Bush et al. (Bush) 4,273,904 Jun. 16, 1981
Fan et al. (Fan) 4,727,110 Feb. 23, 1988
Appellants' claimed invention is directed to a process for
polymerizing monomers of the recited groups via emulsion
polymerization wherein the reaction mixture is moved away from
and back to the reaction vessel through a low-shear pump and a
heat exchanger having an essentially laminar flow profile.
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