Catalyst – solid sorbent – or support therefor: product or process – Catalyst or precursor therefor – Organic compound containing
Reexamination Certificate
1999-05-06
2002-05-28
Bell, Mark L. (Department: 1755)
Catalyst, solid sorbent, or support therefor: product or process
Catalyst or precursor therefor
Organic compound containing
C502S126000, C502S125000, C502S123000, C502S132000, C502S134000, C526S124300, C526S125300, C526S125600
Reexamination Certificate
active
06395670
ABSTRACT:
The present invention relates to catalyst components for the polymerization of olefins, in particular propylene, comprising a Mg dihalide based support on which are deposited a Ti compound having at least one Ti-halogen bond and at least two electron donor compounds selected from specific classes. The present invention further relates to the catalysts obtained from said components and to their use in processes for the polymerization of olefins. The catalysts of the present invention are able to give, with high yields, polymers characterized by high xylene insolubility, a broad range of isotacticity and are further characterized by a good balance between hydrogen response and isotacticity.
Catalyst components for the stereospecific polymerization of olefins are widely known in the art. Basically two types of catalyst systems are used in the normal processes for the (co)polymerization of olefins. The first one, in its broadest definition, comprises TiCl
3
based catalysts components, obtained for example by reduction of TiCl
4
with Al-alkyls, used in combination with Al-compounds such as diethylaluminum chloride (DEAC). Despite the good properties of the polymers in terms of isotacticity said catalysts are characterized by a very low activity which causes the presence of large amounts of catalytic residues in the polymers. As a consequence, a further step of deashing is necessary to obtain a polymer having a content of catalytic residue that makes it acceptable for wide use.
The second type of catalyst system comprises a solid catalyst component, constituted by a magnesium dihalide on which are supported a titanium compound and an internal electron donor compound, used in combination with an Al-alkyl compound. Conventionally however, when a higher crystallinity of the polymer is required, also an external donor (for example an alkoxysilane) is needed in order to obtain higher isotacticity. One of the preferred classes of internal donors is constituted by the esters of phthalic acid, diisobutylphthalate being the most used. This catalyst system is capable to give very good performances in terms of activity, isotacticity and xylene insolubility provided that an external electron donor compound is used. In its absence, low yields, low xylene insolubility and poor isotacticity are obtained. On the other hand, when the external donor is used, high xylene insolubility is obtained only together with a high isotacticity. This is not desirable in certain applications, such as production of bi-oriented polypropylene films (BOPP), where polypropylenes are required to have a lower flexural modulus (obtainable by lowering crystallinity of the polymer) while at the same time retaining a high xylene insolubility. As a consequence, it would be desirable to have a catalyst component with still improved characteristics, particularly in terms of activity and isotacticity, as well a catalyst component capable to give polymers coupling high xylene insolubility with a slight lower crystallinity suitable for making the polymers usable in the BOPP sector. Some improvements are obtained when, in the above mentioned catalyst system, the phthalates are substituted by the electron donor compounds disclosed for example in U.S. Pat. No. 4,971,937. In this case, the catalyst components obtained are capable to give better results when used in the absence of an external donor. In particular, the stereoregularity becomes acceptable, while however the xylene insolubility is still to be improved. Also in this case, when the catalyst component is used together with an external donor, high xylene insolubility isnobtaied only together with a high isotacticity.
It is therefore felt the need of a versatile catalyst component which, for high values of xylene insolubility, is capable to give polymers with a broader range of isotacticity. Moreover, it/would be also advantageous to have a catalyst component with still improved features in terms of activity and isotacticity.
It has now unexpectedly been found a catalyst component having the above advantages which comprises Mg, Ti, halogen and two electron donor compounds selected from specific classes.
It is therefore an object of the present invention a catalyst component for the polymerization of olefins CH
2
═CHR, in which R is hydrogen or a hydrocarbyl radical with 1-12 carbon atoms, comprising Mg, Ti, halogen and at least two electron donor compounds, said catalyst component being characterized by the fact that at least one of the electron donor compounds is selected from ethers containing two or more ether groups which are/further characterized by the formation of complexes with anhydrous magnesium dichloride in an amount less than 60 mmoles per 100 g of MgCl
2
and by the failure of entering into substitution reactions with TiCl
4
or by reacting in that way for less than 50% by moles, and at least another electron donor compound is selected from esters of mono or polycarboxylic acids.
The conditions under which, the reactivity toward titanium tetrachloride and the complexing activity of the di or polyethers are tested, are reported below.
Very surprisingly it has been found that the performances of the above-disclosed catalysts are not merely intermediate between those of the catalyst components containing the single donors. While we do not intend being bound to any theoretical interpretation, it can be said that a synergic interaction between the elements of the catalyst component, and maybe in particular between the above mentioned donors, is the basis for explaining the unexpected properties of the catalyst component of the invention.
Among the di or polyethers mentioned above, particularly preferred are the compounds belonging to the class of the 1,3-diethers. In particular, preferred 1,3-diethers are those of formula (I)
where R
I
and R
II
are the same or different and are hydrogen or linear or branched C
1
-C
18
hydrocarbon groups which can also form one or more cyclic structures; R
III
groups, equal or different from each other, are hydrogen or C
1
-C
18
hydrocarbon groups; R
IV
groups equal or different from each other, have the same meaning of R
III
except that they cannot be hydrogen; each of R
I
to R
IV
groups can contain heteroatoms selected from halogens, N, O, S and Si.
Preferably, R
IV
is a 1-6 carbon atom alkyl radical and more particularly a methyl while the R
III
radicals are preferably hydrogen. Moreover, when R
I
is methyl, ethyl, propyl, or isopropyl, R
II
can be ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, isopentyl, 2-ethyihexyl, cyclopentyl, cyclohexyl, methylcyclohexyl, phenyl or benzyl; when R
I
is hydrogen, R
II
can be ethyl, butyl, sec-butyl, tert-butyl, 2-ethylhexyl, cyclohexylethyl, diphenylmethyl, p-chlorophenyl, 1-naphthyl, 1-decahydronaphthyl; R
I
and R
II
can also be the same and can be ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, neopentyl, phenyl, benzyl, cyclohexyl, cyclopentyl.
Specific examples of ethers that can be advantageously used include: 2-(2-ethylhexyl)1,3-dimethoxypropane, 2-isopropyl-1,3-dimethoxypropane, 2-butyl-1,3-dimethoxypropane, 2-sec-butyl-1,3-dimethoxypropane, 2-cyclohexyl-1,3-dimethoxypropane, 2-phenyl-1,3-dimethoxypropane, 2-tert-butyl-1,3-dimethoxypropane, 2-cumyl-1,3-dimethoxypropane, 2-(2-phenylethyl)-1,3-dimethoxypropane, 2-(2-cyclohexylethyl)-1,3-dimethoxypropane, 2-(p-chlorophenyl)-1,3-dimethoxypropane, 2-(diphenylmethyl)-1,3-dimethoxypropane, 2(1-naphthyl)-1,3-dimethoxypropane, 2(p-fluorophenyl)-1,3-dimethoxypropane, 2(1-decahydronaphthyl)-1,3-dimethoxypropane, 2(p-tert-butylphenyl)-1,3-dimethoxypropane, 2,2-dicyclohexyl-1,3-dimethoxypropane, 2,2-diethyl-1,3-dimethoxypropane, 2,2-dipropyl-1,3-dimethoxypropane, 2,2-dibutyl-1,3-dimethoxypropane, 2,2-diethyl-1,3-diethoxypropane, 2,2-dicyclopentyl-1,3-dimethoxypropane, 2,2-dipropyl-1,3-diethoxypropane, 2,2-dibutyl-1,3-diethoxypropane, 2-methyl-2-ethyl-1,3-dimethoxypropane, 2-methyl-2-propyl-1,3-dimethoxypropane, 2-methyl-2-benzyl-1,3-dimethoxypropane, 2-methyl-2-phenyl-1,3-dimethoxypropane, 2-methyl-2-cyclohexy
Balbontin Giulio
Morini Giampiero
Vitale Gianni
Basell Technology Company BV
Bell Mark L.
Bryan Cave LLP
Pasterczyk J.
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