Patent ID: 6066706
Filing Date: 2000-05-23
Classification: C08F,Y10S

Abstract:
A process for the preparation of crystalline vinylaromatic polymers with a predominantly syndiotactic structure which comprises polymerizing vinylaromatic monomers, alone or mixed with at least another copolymerizable ethylenically unsaturated monomer, in the presence of a catalytic system consisting essentially of:a) an adduct between a derivative of titanium having the formula R.sub.1 R.sub.2 R.sub.3 R.sub.4 Ti and a calix-[n]-arene, or an oxa-calix-[n]-arene, having formula (I): ##STR5## wherein R.sub.1,R.sub.2, R.sub.3 and R.sub.4, the same or different, represent a halogen, a C.sub.1 -C.sub.4 alkyl radical, a C.sub.1 -C.sub.4 (iso)alkoxylic radical, a cyclopentadienyl group or a dialkylamino group in which the alkyl radical contains from 1 to 4 carbon atoms;R represents a halogen, or a C.sub.1 -C.sub.4 (iso)alkyl radical, X is selected from bifunctional --CY.sub.1 Y.sub.2 -- or --CY.sub.1 Y.sub.2 --O--CY.sub.1 Y.sub.2 -- radicals in which the substituents Y.sub.1 and Y.sub.2, the same or different, represent a hydrogen atom, a methyl or a phenyl group, n is an integer between 3 and 8;b) a co-catalyst selected from an alkylalumoxane and a compound of boron having the formula (II):BX.sub.1 X.sub.2 X.sub.3 (II)or its salt, wherein X.sub.1, X.sub.2 and X.sub.3, the same or different, represent a C.sub.1 -C.sub.20 fluorinated hydrocarbon radical.