Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Polymers from only ethylenic monomers or processes of...
Patent
1992-06-22
1998-01-20
Wu, David W.
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Polymers from only ethylenic monomers or processes of...
526126, 526160, 526170, 526943, 526351, 502152, 502155, C08F 464
Patent
active
057102228
ABSTRACT:
This invention is for a method for varying the melting points and molecular weights of syndiotactic polyolefins by using metallocene catalysts with substituents on the aryl rings of a fluorene ligand in certain positions. Electron donating substituents, for example, dialkylamino, halogen, and alkoxy groups, when present on fluorene at C1, C2, C3 or C2 and C7 render the catalyst less active and decrease the polymer molecular weight. Electron donating substituents, such as alkyl, dialkylamino, halogen or alkoxy, at C4 not only increased the catalyst efficiency but also dramatically increased the polymer molecular weight. Bulky hydrocarbyl substituents, such as alkyl, cyaloalkyl and aryl groups, at C2 and C7 increase the melting point. Bulky substituents such as hydrocarbyl groups like alkyl, cycloalkyl, aryl, alkoxy and dialkylamino groups etc., at C4/C5 decrease the melting point. When multiple substituents are present on fluorene, their effects are additive.
REFERENCES:
patent: 5132381 (1992-07-01), Winter et al.
patent: 5155080 (1992-10-01), Elder et al.
patent: 5225501 (1993-07-01), Fujita et al.
patent: 5401817 (1995-03-01), Palackal et al.
Elder Michael J.
Ewen John A.
Reddy B. R.
Cheairs M. Norwood
Fina Technology, Inc.
Wheelington Jim
Wu David W.
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