Appeal No. 1999-1679 2
Application No. 08/851,742
required that the initial preparation of the polymerization catalyst be in the absence of an
electron donor. Subsequent to the first step of catalytic preparation an electron donor is
utilized provided that electron donors which are alcohols, phenols, silanes and polysiloxanes
are excluded from among those utilized in the preparation of said polymerization catalysts.
Additional limitations are described in the following illustrative claim.
THE CLAIM
Claim 1 is illustrative of appellant’s invention and is reproduced below:
1. A process for the manufacture of ethylene homopolymers and
copolymers containing at least 90 mol% of ethylene, according to which ethylene in
a polymerization medium is placed in contact with a catalytic system comprising:
a) a solid catalytic complex based on magnesium, on transition metal and
on halogen, the said catalytic complex being prepared by reacting, in
a first step, in the absence of an electron donor, at least one
magnesium compound chosen from oxygen-containing organic
magnesium compounds and halogen-containing magnesium
compounds with at least one compound of a transition metal from
group IVB or VB of the Periodic Table chosen from oxygen-
containing organic compounds and halogen-containing compounds of
a transition metal, until a liquid complex is obtained, and, in a
subsequent step, by precipitating the said liquid complex using a
halogen-containing organoaluminum compound of general formula
A1RnX3-n in which R is a hydrocarbon radical, X is a halogen and n is
less than 3, in order to collect a solid catalytic complex,
b) an organometallic compound of a metal from groups IA, IIA, IIB,
IIIA and IVA of the Periodic Table, and
c) at least one electron donor selected from the group consisting of
organic compounds containing at least one atom or at least one group
of atoms having at least one pair of free electrons, with the exception
of alcohols, phenols, silanes, and polysiloxanes, said at least one
Page: Previous 1 2 3 4 5 6 7 8 9 10 Next
Last modified: November 3, 2007