Catalyst – solid sorbent – or support therefor: product or process – Catalyst or precursor therefor – Plural component system comprising a - group i to iv metal...
Reexamination Certificate
2001-03-08
2003-02-25
Wu, David W. (Department: 1713)
Catalyst, solid sorbent, or support therefor: product or process
Catalyst or precursor therefor
Plural component system comprising a - group i to iv metal...
C502S118000, C502S132000, C502S133000, C526S124300, C526S904000, C526S908000
Reexamination Certificate
active
06524986
ABSTRACT:
The present invention relates to a catalyst support and to a process for obtaining this support. The present invention also relates to catalysts for the polymerization of &agr;-olefins, obtained starting with these supports, a process for obtaining these catalysts and a process for the polymerization of &agr;-olefins in their presence.
It is known to polymerize &agr;-olefins by means of catalysts deposited in, or on, porous polymeric supports (EP-0283011; EP-0314131 and EP-344755). According to these documents the polymeric supports which give the best results are (co)polymers of styrene and of divinyl-benzene and polyvinyl chlorides.
In the manufacture of catalysts for the polymerization of &agr;-olefins, the use of these supports of a chemical nature which differs from those of the final polymers and generally of high weight-average molecular mass in most cases results in &agr;-olefins polymers which do not exhibit the desired best qualities. In particular, when they are used, it is noted that agglomerates originating from the catalysts are formed and deteriorate the properties of the objects obtained.
Furthermore, it is generally difficult to modify the morphology of these supports. Finally, they are generally costly and this reduces the economic advantages of the catalysts thus obtained.
The use of &agr;-olefins polymers as support allows these problems to be partly solved (EP-0523879). This document describes specifically the use, as support, of (&agr;-olefin polymer particles larger than 150 &mgr;m in size. The use of particles of this size results, ultimately, in the formation of polymer particles of very large size which are difficult to handle and can be conveyed by the usual pneumatic means. Furthermore, the supports employed in this document must be pretreated in order to obtain the desired morphology.
The present invention consequently aims to obtain, in an economically advantageous manner, a polymeric support of a catalyst for the polymerization of &agr;-olefins which is completely compatible with the final polymer and which does not exhibit the disadvantages of the polymeric supports forming part of the prior art.
To this end, the invention concerns, chiefly, a catalyst support including at least one polymer of &agr;-olefins(s), which is in the form of particles with a mean size of 5 to 350 &mgr;m and in which the pore volume generated by the pores of radius from 1000 to 75,000 Å (10
−10
m) is at least 0.2 cm
3
/g.
&agr;-Olefin polymers are intended essentially to mean the homopolymers and copolymers of &agr;-olefins containing from 2 to 20 carbon atoms, such as, for example, ethylene, propylene, 1-butene, 1-pentene, 1-hexene, methyl-1-butenes, methyl-1-pentenes, 1-octene and 1-decene.
Within the scope of the present invention, &agr;-olefin polymers being considered also include the copolymers of the &agr;-olefins described above with other unsaturated monomers such as, for example, unsaturated organic acids and their derivatives, vinyl esters, aromatic vinyl compounds, vinylsilanes and unconjugated aliphatic and monocyclic diolefins, alicyclic diolefins which have an endocyclic bridge and conjugated aliphatic diolefins.
The polymeric supports according to the present invention are preferably chosen from the homopolymers of &agr;-olefins containing from 2 to 15, preferably from 2 to 8, carbon atoms and the copolymers of these &agr;-olefins with each other. Propylene homo- and copolymers are particularly suitable.
One advantage of the supports according to the present invention is that they are in the form of particles of very variable size. The mean size of these particles can reach values as low as 5 &mgr;m. This size is generally larger than or equal to 8 &mgr;m and preferably larger than or equal to 15 &mgr;m. In most cases these particles have a mean size smaller than or equal to 350 &mgr;m, preferably smaller than or equal to 190 &mgr;m, and more particularly smaller than or equal to 150 &mgr;m. Supports which are particularly preferred have a mean size of 20 to 120 &mgr;m.
The pore volume of these supports is also one of their important characteristics. In most cases they have a pore volume generated by the pores of radius from 1,000 to 75,000 Å (10
−10
m) of at least 0.2 cm
3
/g. This pore volume is preferably at least 0.3 cm
3
/g and more particularly at least 0.5 cm
3
/g.
The polymeric supports according to the present invention generally contain a certain quantity of catalyst residues originating from the catalyst systems (S), as defined below, which, have given rise to them. These catalyst residues, expressed as weight of the compound (a) defined below per kg of support, are in most cases of at least approximately 0.3 g, preferably of at least approximately 2 g and more particularly of at least approximately 5 g of compound (a) per kg of support. It is furthermore desirable that this quantity of catalyst residues should be smaller than or equal to approximately 170 g, generally smaller than or equal to approximately 90 g and more particularly smaller than or equal to approximately 60 g of compound (a) per kg of support. Particularly good results are obtained when the quantity of catalyst residue is from 10 to 50 g of compound (a) per kg of support.
It is obvious that the supports which have subsequently been subjected to a treatment aimed at removing these catalyst residues from them are also included within the scope of the present invention.
The use of these supports for the preparation of catalysts for the polymerization of &agr;-olefins make it possible to obtain polymers in which the content of inorganic compounds, generally called ash content, is particularly low.
In a second aspect, the present invention concerns a process for obtaining these supports.
The supports according to the present invention are generally obtained by polymerization of one or more &agr;-olefins as defined above by means of a catalyst system (S) containing a catalytic compound (a) based on a transition metal belonging to groups IIIb, IVb, Vb and VIb of the Periodic Table (version published in the Handbook of Chemistry and Physics, 50th edition, page B-3—1969-1970) and an activator chosen from organoaluminium compounds and, in general, those containing at least one aluminium-carbon bond and optionally capable of containing oxygen and/or one or more halogens.
The activator is preferably chosen from the compounds corresponding to the overall formula
AlR
1
x
X
3−x
(I)
in which
R
1
is a hydrocarbon radical containing from 1 to 18 carbon atoms;
X is a halogen; and
x is any number such that 0<x≦3.
The catalytic compound (a) employed for the manufacture of the supports according to the invention is generally in the form of particles whose mean size is at least 2 &mgr;m. These particles are preferably such that their mean size is at least 5 &mgr;m and more particularly at least 10 &mgr;m. This size is generally smaller than or equal to 200 &mgr;m, in most cases smaller than or equal to 100 &mgr;m and preferably smaller than or equal to 50 &mgr;m. The pore volume of these particles of compound (a) generated by the pores of radius from 200 to 15,000 Å (10
−10
m) is at least 0.02 cm
3
/g, preferably at least 0.05 and more particularly at least 0.1 cm
3
/g. This pore volume is furthermore generally smaller than 1 cm
3
/g.
In most cases this catalytic compound (a) is a solid compound based on TiCl
3
of &dgr; crystalline form as defined, for example, in Journal of Polymer Science 51, pages 399-410 (1961), obtained by a process involving the reduction of a tetravalent titanium compound with an organoaluminium reducing agent.
A catalytic compound (a) is preferably employed which is obtained by heat treatment, in the presence of a halogen-containing agent, of the liquid material resulting from placing titanium tetrachloride (TiCl
4
) pretreated with an electron-donor compound, in contact with a composition (D) corresponding to the general formula
AlR
p
(Y)
q
X
3−
(p+q)
(II)
in which
R denotes a hydrocar
Costa Jean-Louis
Francois Philippe
Laurent Vincent
Vercammen Dirk
Rabago R.
Schneller Marina V.
Solvay Polyolefins Europe-Belgium
Venable
Wu David W.
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