Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Polymerizing in tubular or loop reactor
Reexamination Certificate
2005-07-26
2005-07-26
Cheung, William K. (Department: 1713)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Polymerizing in tubular or loop reactor
C526S075000, C526S106000, C526S348500, C526S352000
Reexamination Certificate
active
06921798
ABSTRACT:
Polymerization processes are disclosed for producing polyethylene having a target density and improved environmental stress resistance. Ethylene and optionally one or more α-olefin comonomers, supported chromium catalyst, and metal alkyl cocatalyst are contacted to produce polyethylene. The density of the polyethylene is determined, and the concentration of cocatalyst is adjusted in response to a deviation between the density of the polyethylene and the target density. The catalyst and cocatalyst can be fed separately into the reactor, or can be co-fed, eliminating the need to pre-contact the catalyst and cocatalyst prior to introducing them into the reactor.
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Abstract from MicroPatent for EP 0 885 656, entitled Catalytic Composition and Ethylene Oligomerization, Especially in 1-Butene and/or 1-Hexene, published Dec. 23, 1998 (see AO).
Katzen Stanley J.
Kendrick James A.
Lin Zerong
Roger Scott T.
Speca Anthony N.
Cheung William K.
ExxonMobil Chemical Patents Inc.
Griffis Andrew B.
Walsh Maria C.
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