CA1117096A - Sizing and shaping of catalysts - Google Patents

Abstract

ABSTRACT OF THE DISCLOSURE
Solid catalyst particles are made into a form and shape that is casier to handle, without changing their surface area or ad-versely affecting their activity by "matting" the catalyst particles with a fibrillatabie p?retrafluoroethylene polymer by mechanical cleanie? acties and subsequently shaping the "mat", followed by controlled sizing and shaping into the form of pellets, tablets, and the like by known mechanical meaur. Activity is not impaired, and shaped polymer can be produced in those reactions where the catalyst determines the shape of the product. The practice of this invention is particularly useful to shaped Ziegler-type catalysts.

Description

1 Catalysts of various sort~, specifically heterogen-

2 eous catalysts, usually have a shortcoming: they are diffi-

3 cult to handle. Techniques to modify these catalysts so

4 that they are more easily handled are limited. For examplç, S agglomeration with "binders" is unsuitable since "binders"
6 normally poison the catalyst sites.
7 Techniques such as sieving the heterogeneous cata-8 lysts to remove the catalyst "fines" is a possible tech-9 nique; however, it is a technique that is expensive. Fur 0 thermore, a catalyst manufacturer must then have an outlet for the catalyst "fines" which he accumulates.
12 Certain heterogeneous catalysts may be sintered 13 with a binder with concomitant loss of catslyst sites. The 4 sintered material may then be extruded or fractured to yield a large heterogeneous catalyst The problem with this pro-16 cedure is that it is not applicable to all heterogeneous 7 catalysts, and in some cases damages the catalyst.
8 With certain catalysts such as olefin polymeriza-19 tion catalysts, the growth of the catalyst itself from the original catalyst seeds can be controlled to yield pr~ducts 21 having a coarse structure (20 microns or larger~ which makes 22 these catalysts more easily handled. ~U.S Patent 3,623,846) 23 described a process for controlling particle size during 24 condensation and/or desublimation of a material such as ti-tanium trichloride which may be used in the polymeriæation 26 of alpha-olefins-27 In another example as described in British Patent 28 1,139,450, TiC13 catalysts are formed by controlled reduction 29 of titanium tetrachloride with aluminum alkyls. These mater-ials hsve a narraw particle size distribution, and have an 31 average diameter greater than 15 microns, and therefore are 32 relatively easy to handle 1 However, the latter two examples illustrating two 2 techniques for improvin~ the particle size of catalysts, 3 specifically titaniu~ trichloride olefin poly~erization 4 catalysts, have certain limitations~ Thus, although the catalyst particle size is greater than the l micron dimen-6 sion which is normally available, the 20 micron size still 7 li~its the useability of these catalysts. Incre~se in cata-8 lyst ~rowth to yield particles lO0 microns or larger is more 9 difficult. Furthermore, control of particle slze during lo cataly3t synthesis is a proble~ unique to every type of 11 catalyst that might be employedO What is des~red, there-12 fore, is a technique that i~ applicable to hetero~eneous 3 catalysts in general, a procedure that is easy to employ, 14 and one that can yield catalysts in shapes and sizes most suitable to each process in which the catalyst i8 to be used.
16 In U~SO Patent 3,990,993 a procedure is described 7 whereby olefin poly~erization catalysts, i~e. Ziegler TiC13-18 nAlC13, can be mechanically treated with a fibrlllatable 19 polytetrafluoroethylene (PTFE) in order to trap the catalyst "fines" in a web of PTFE microscopic fiber~, thus producing 21 a cataly~t of lar~er particle size having a m~rç narrow 22 particle-size distributionO Nevertheless, the catalyst is 23 still limited in size obtainable and in particle size dis-24 tribution by the randomizing ~echnique of fracturing the catalyst-PTFE ~ixture~
26 Further, as an expression of the prior art, U.S.
27 Patent 3,051,662 describes the use of polyolefins as binders 28 and lubricants for shaping solid ~aterials. The disclosure 29 teaches the formation of simple mixtures which sre extruded through a die. In so~e instances where metal oxide cata-31 lysts are involved, the lubricant-binder of the invention 32 is removed, usually by incineration or vaporization. This 7~ ~ ~

l would destroy the activity of msny cataly~ts. PTFE is only 2 casually mentioned, and the disclosure fails completely to 3 recognize the importance of the ~nvention as disclosed and 4 claimed herein. While it is pointed out that the patentee is concerned with the particle size range of various cata-6 lytic materials and the desirability to form these materials 7 into large,uniform, easily handled shapes, U.S. Patent 8 3,990,993 clearly expresses concern for fines resulting 9 from ballmilling of polyolefin catalystsO Such concern i8 unnecessary in the practice of this invention.
11 Further UOSO Patents 3,838,062, 3,838,092, and l2 3,993,584 disclose the use of a fibrillatable PTFE to create 13 a weak agglomerate of dusts, particularly toxic dusts.
14 Particles of catalyst used in heterogeneous re-actions are mixed with a fibrillatable polymer, and mechan-6 ically sheared to form a coherent mat having the catalyst 17 particles entrapped in the fibers of the polymerO The mat l8 is mechanically shaped, either by rolling and cutting, ex-l9 trusion, or by some other known method, to produce a catalyst of uniform size and shape which is easily handled and which 21 has lost none of its activity as a result of the mechanical 22 work.
23 The practice of this invention is particularly 2a suited to the sizing and shaping of Ziegler-type catalysts for the production of polyolefinsO In practicing this inven-26 tion, it becomes possible for those ~killed in the art to 27 produce finished pellets of polypropylene directly in the 28 polymer-forming reaction by using the known polymerization 29 conditions and the shaped catalyst materials.
The drawing attached hereto is a photographic re-31 production showing material resulting from the steps of this 32 invention from lmprovement of a preferred Ziegler-type 1~.171~

catalyst through the various steps to the finished polypropylene polymer.
It has been discovered that heterogeneous solid catalyst particles can be mechanically worked into large mats or agglomerates of materials and can be subsequently shaped into briquets, pellets, tablets, or other forms.
The invention described herein can well be illustrated with the use of olefin polymerization catalysts, specifically TiC13 catalysts; however, it is unders~ood that the principles illustrated with respect to this catalyst also apply to the other heterogeneous catalysts described by M. Sittig, in "Catalysts, Manufacture, Recovery and Use" 1972, Noyes Data Corporation, Park Ridge, New Jersey 07656, U.S.A., since the principle of controlling the shape of a heterogeneous catalyst applies, independent of the nature of the catalyst.
It is known that, for example, Ziegler-type TiC13 catalysts which are normally used ln the production of poly-olefins, are in a very finely subdivided form where the particles normally have a particle size distribution of 0.1-100 microns. The fine particle size plus the wide particle distribution makes this catalyst difficult to handle~, and this catalyst in a liquid medium becomes a sludge which is also difficult to resuspend once the catalyst has settled.
Bottle No. 1 in the Drawing illustrates the condition of active TiCl3AA (reduced with aluminum and ball-milled) catalyst particles before the practice of this invention.
It has been found that if the catalyst particles are mechanically treated with a small amount of fibrilla-table polytetrafluoroethylene (PTFE), the catalyst is matted with the polytetrafluoroethylene and becomes a large cake of material having the catalyst particles entrapped in the fibrous network of the polyolefin. This cake will subse-quently be referred to herein as a "mat". It has been ob-_ _ _ _ _ _ _ _ ~ ~ 7~ ~ ~

l served that the catalyst sites are affected only to a negli-2 gible degree, and that the activity of the catalyst is unim-3 paired. This mat, which is malleable, can be subsequently 4 shaped to any convenien~ shape, depending on the type of end use that is desired. The mat can be forced through a circu-6 lar die at room temperature or high temperature to yield a 7 strand of material which, upon cutting, ylelds pellets of 8 catalysts. On the other hand, the matted catalyst-agglome~ate 9 may be st~mped with a sharp conical instrument, or pressed in~
0 to molds to yield tablets of material. ~rprisi~gly, the ac-ll tive sites on the catalyst particles are not obscured by 12 this shaping 13 The techniques used to shape the catalyst mat int~
14 specific forms are well-known to those skilled in the art, and are partially summarized by G.E. Browning; "Agglomeration"
16 Chemical En~ineering, December 4, 1967, pp l47-170. This 17 publication describes the shaping of matted materials with, l3 for example, single punch press, rotary press, layer press, 19 molding press, smooth-roll type press, briquetters or granu-lators, smooth or corrugated roll type press, pellet mills, 21 and the like, which can be used forming spheroidal or tablet-22 like particles.
23 In the practice of this invention, a mixture of 24 the solid catalyst particles and the fibrillatable poly-tetrafluoroethylene is made ~uch that the polytetrafluoro-26 ethylqne is present in an amount from about 0.01 wt. ~ to 27 about 5 wt. C/. of the mix and, preferably, ~rom about 0.5 28 wt. ~ to 2 wt. Z. Even though greater amounts than 5 wt. ~
29 can be used, there is some risk involved to the active sites of the cat~lysts which, under the practice of the pre ent in-3l vention, remain rem~rkably active.
32 With respect to the polytetrafluoroethylene useful 33 in the practice of the invention9 it is necessary that it be 1 fibrillatable A fibrillatable polytetrafluorethylene is 2 one which, on being subjected to shearlng stresses, for~s 8 3 fibrous network of small fibers, often microscopically sized 4 fibers, which entrap the solid catalyst particles. There are two types of suitsble polytetrafluorethylenes (PTFE). One 6 is a colloidal aqueous dispersion concentrated to about 7 60% by weight of polymer, havlng particles about 0O05 to 8 about 0.5 microns in size, with average diameters of about 9 0.02 mlcrons~ This aqueous dispersion, of course, could be used in the instance where the solid catalytic particles are 11 insensitive to the presence of water. Of course, where there 2 is a water sensitivity9 such colloidal aqueous disper$ion 13 could not be used. In such a case, the PTFE, in the practice 14 of this invention, consists of solid agglomerates with aver-age diameters of 450 microns, made up of primary particles 16 ranging in size from 0.05 to 0O5 microns i~ diameter. Speci-17 fic surface areas of PTFE powders are of the or~er of l0-12 18 m3/g with an ~verage apparent powder density of 475 ~/liter.
19 The fore~ing types of PTFE are more fully described in U.S.
Patent 2,559,752. While other fibrillatable polytetrafluoro~
21 ethylenes are useful in the practice of this invention, the r 22 PTFE, sold as Teflon K by the duPont Company, i9 preferred.
23 The light powder known as Teflon K, Type l0, i8 24 worked at a temperature of from about 20Co to about 120C., and preferably, of course, at a~bient conditions. The com-26 mon working temperature in order to produce a flbrous mat, 27 is below 100C.
28 O~ce mixed, the catalyst particles and the PTFE
~ are mechanically sheared, such that the PTFE becomes fibril-la~ed and the catalyst particles entrapped in a fibrous net-31 work of polytetrafluoroethylene~ This shearing action is 32 done mechanically in any one of a number of well-known com-~ " (~"/~ k _ 7 -1 mercially available pieces of equipment such as a ball mill, 2 pugg ~ill, blender, or the like. Thls mechanical shearin~ is 3 performed for from about one to about sixty minutes, with 4 the preferable period from five to about forty minutes and most preferably, from ten to about twenty-five minutes. Of 6 course, longer times can be used, but serve no useful purpose 7 once the shapable fibrous mat is formed. Such a mat is easlly 8 recognized, and one æuch mat is shown in bottle No. 2 of the 9 drawing. The mixing time, of course, is dependent upon the lo temperature of mixing and the concentration of the PTFE in 11 the mix. When at higher temperatures, the mixing time ls re-12 duced, as is the mixing time w~en a higher concentration of 13 the fibrillatable polyolefins is used. When PTFE is used 14 in the fibrillatable polymer and 8 Ziegler-type catslys~ was being subjected to the practice of this invention, examina-16 tion of the mat formed under a microscope shows a very fine 17 microscopic web holding the particles of the catalyst. Quite 8 remarkably, even though it is well known that the Ziegler-19 type catalysts are readily poisoned, the activity of such catalysts was virtually unaffected, even after having been 21 molded in pellets, such as those shown in bottle No. 3 of 22 the drawin~
23 In the practice of the method of this invention, 24 these shaped catalysts, whether they be in the form of pel-lets, tablets, or any other sh~pe, can be used in heterogen-26 eous reactions, particularly in the case where the well 27 known Ziegler-type catalysts are used to make polypropylene 28 or other p~lyolefi~s. In ru~ning a normal Ziegler-type reac-29 tion to make polypropylene under polymerization conditions, ~ pellets of polymer ~ere produced which appeared as shown in 31 bottle No. 4 of the drawing. After an alcohol treatment to 32 remove the catalyst, using known procedures, the finished 1 polypropylene, in the form of uniform, large-sized pellets, 2 was produced and recovered from the reaction system obviat-3 ing the necessity of ~eparately forming finished polypropyl-4 ene into a desired shape. Thus, surprisingly, shaped poly-propylene can be produced by merely conducting the polymer-6 ization of propylene under polymerization conditions, with 7 a Ziegler type, titanium-containing catalyst wh~ch has been 8 shaped in the practice of this inventionO In addition to 9 the different catalyst heretofore described as being applic-able in the practice of this invention, the TiC13 catalyst for olefin polymerization which is supported on a salt ~uch 12 as magnesium chloride or sodium chloride, catalysts well l3 known in the art, are also particularly applicable to the 14 practice of this invention~ Promoters or modifiers may also be present in catalysts or particles subjected to the treat-16 ment of this inventionO Catalyst mcdification techniques l7 are well known to th~se skilled ln the art and the practice 18 of this invention relates to t~e treatment of the catalyst l9 particle itself and not to the formation of any specific ca~alyst, even though its practice with Ziegler-type polymer-21 ization catalysts and f~brillatable polytetrafluoroethylene 22 i8 preferred.
23 A preferred embodiment of this invention is parti-24 cularly adaptable to the treatment of Ziegler-type titaniu~-halide catalysts, eOgO, catalysts obtained by reduction of 26 the tetrahalide of titanium to a Ti compound with a lower 27 oxidation state, such as Ticl3oxAlcl3 where x ranges be-28 tween 0.01 to 1.5; TiClmoxAI ~ C13_n, where x ran~e~ between 29 0.01 to 1.5, m ranges between 2 to 3O5~ n ranges betweeP 0.01 to 3, ant R i an organic radical such as an organic hydro-31 carbon, preferably alkyl having from one to about 5 carbons, 32 such as CH3, C2H59 C3H7, etc., or other organic radical that ~7 ~ ~ ~

I normally is known as described by Mole and Jeffrey, "Organo-2 aluminu~ Compounds", Elsevier, (1972), MX'm M'RnX3 n where 3 metals, M, are of Groups IIIB, IVB and VB of the Periodic 4 Table, and M' are elements of Groups IA, IIA, IIIA of the S Periodic Table, X snd X~ are elements of Groups VIA and 6 VIIA of-the Periodic Table, i.eO the Periodic Table of 7 Mendeleef as published in the Handbook of Chemistry and 8 Physics, 56th Edition, CRC Press, Cleveland, Ohio U.S.A.
9 And m, x and n vary as described above. It is well known 0 that the compounds induced are mi~ture~ and that the ranges ll of values of m, x and n herein are average values.
12 Further, while it is preferred that t~e mat of 13 fibrillated polyolefin and catalyst particles be formed in 14 the dry state, it is also possible to create the entrapment of the catalytic particles in the presence of an inert dilu-16 uent such as hydrocarbon, i.e. heptane and the like. Of l7 course, the selection of the hydrocarbon involved would be 8 dependen~ upon the catalyst and diluents with which particu-19 lar catalysts are compatibleO
ao This inve~tion is applicable to many catalysts of 21 differing nature. These and o~her features of the invention 22 will thus be illustrated by the following examples, which 23 are offered for the pu~se ~f illustration and not limita-24 tion 26 To a mortar and pestle were added 9.8 gms of 27 TiC13-0.33 AlC13 known as TiC13AA obtained from Stauffer 2g Che~ical Co~any. This is a ball-milled catalyst having a broad particle size distributionO To the mortar and pestle were added also 0.2 gms of fibrillatable PTFE (Teflon K).
31 The Te~lon K is a white powder, type 10, which is used and 32 sold as a particle control additlve The two materials were : ",, ~ " ~

~ 10 -1 mechanically mixed 8t room temperature with a pestle until 2 the material was in the shape of a mat. The mat wa irregu 3 lar in shape and had various dimen~ions where in one caAe 4 the dimension was 40 x 20 x 4 millimeters (Bottle No. 2). A
S similar type mst can be formed by using a metal container 6 known as a vibramill, having three chrome alloy steel balls, 7 3/8" in diameter, and adding to this container the same 8 amount of catalyst and Teflon K. In this case, the contents 9 of the mill were rapidly shaken for a period of 5 to 30 minutes. Again, a large mat of material was the product.
ll EXAMPLE 2 l2 A 13 gauge needle, with an open blunt end, was 13 forced through the mat prepared in Example 1, and the needle 14 was thereby packed with a column of matted catalyst. The column of catalyst was forced out of the needle and cut with 16 a sharp object yielding pellets which were 1~8 by 2 milli-7 meters in size.8 The size dimensions are given for solids in the 19 shape of right cylinders, with a base of diameter "a" and altitude "b". The volume of these right cylinders i~ given 21 by the standard formula, V s ~ (a/232b. The shapes of the 22 particles obtained in Examples 2-44 are all right cylinders.

24 In a manner similar to Example 2, a cork borer with a 7 millimeter diameter hole was forced through the mat 26 prepared in Exa~ple 1, and a tablet, 3 millimeters in thick-27 ness, w~s forced out of the cork borer. Table 1 summarizes 28 the results of the mechanical shapingO

2 MECHANICAL SHAPING OF TiCL~ CATALYSTS
3 Example TiC13~0.3AlC13 PTFE Cstalyst Catalyst 4 No. gmg gms. wt. % Shape Size, mm 1 9 . 8 0 . 2 2 Irregular 40x20x4 6 Mat 7 2 9.8 0.2 2 Pellets 1.8x2 8 3 9 . 8 0 . 2 2 Tablet 7x3 lQ Catalyst pellets were prepared according to the 11 procedure de~cribed in Examples 1-2, using needles,having 12 different diameters. As illustrated in Table 2, pellets of 13 different sizes are obtained.

PELLETS OF ~iCl ~ OLEFIN POLYMERIZATION CATALYST
16 Example Catalyst PTFE Needle Dimensions 17 No. ~ms ~ms. wt.% Gauge mm 18 a** b**
19 4 9.9 0.1 1% 10 2.68 2 9~9 0.1 1% 13 1~8 2 21 6 9.9 0~1 1% 15 1.37 2 22 7 9.9 0.1 1~/. 18 0.84 2 23 8 9.9 0.1 1~ 22 0~15 2 24 ** Column a represents diameter 2S Column b represents thickne~s or length _ 27 The effect of titanium trichloride concentratio~
~ on the pelletized catalyst formation is illustrated by 29 Examples 4 and 8-12 where th,e titanium trichloride concen-tration was varied from 95 wt. % to 99.5 wt. %. Conversely, 31 the PTFE concentration varies from 0.5 wt. ~h to 5 wt. %.
32 These examples, detailed in Table 3, illustrate that the 33 actual catalyst concentration can be reduced significantly.

~li70~;

2 EFFECT OF TiC13M CONCENTRATION ON

4 Example Catalyst PTFE, ~eedle Dimension~

5 No, gms. gms. Wt. % Gauge a mm

6 4 9.9 0.1 1% 10 Z~g -Z

7 8 9.9 0.1 1% 22 0 15 2

8 9 4.75 0.25 5% 10 2.68 2*

9 10 4.75 0.25 5% 22 0.15 2*
11 9.95 0.05 0.5% 10 2.68 2 11 12 9.95 0.05 0.5% ~2 0.15 2 12 * Material cakes more easily r 14 The effect of Teflon concentration on the matted catalyst formation i~ illustrated by Examples 13-17 where it 16 was ~hown that the TefIon concentration can vary from 0.01 17 wt. % (Example 17) to at least 2 wt. % (Example 13) as 18 shown in Table 4. The catalyst pellets are formed in a 19 manner similar to the technique described in Examples l and 2. In each example, a pliable mat was formed.

23 MATTED ~ATALYST FORMATIQN ~
24ExampleTiC13 0.33 AlC13 PTFE, No, ~ms ~ wt.%
~6 13 10 0.2 2 ~7 14 10 0.1 28 15 lo 0.05 0.5 29 16 10 0.0125 0.125 17 10 0.001 0.01 31 EXAMPLES 18-~1 32 Examples 18-21 illustrate that supported olefin 33 polymerization samples may, in a similar manner, be shaped.
~" J~ k 1 Thus, supported olefin polymerization catalysts such as 2 TiC13 "supported" on MgC12 may be shaped in a manner similar 3 to the technique described in Examples 1 and 2. This is 4 illustrated in Table 5.

_ _ PE~LETS OF M~Cl~ "SUPPORTED'I OLEFIN
6 PoLyMER~zATIoN CATALYSTS
8 ~xample _ Catalyst PTFE Needle Dimensions,mm g No. Material Gms. Gms. Wt.% Gauge a b ~ .~
18 TiC13AA 9 Ool 1 10 2.68 2 ll MgC12 0-9 12 19 Ticl3M 9 0.1 1 18 a . 84 2 13 MgC12 0.9 14 20 TiC13AA 5 0.1 1 10 2.68 2 MgC12 16 21 TiC13AA 5 0O1 1 22 0.15 17 MgC12 4.9 cofored 18 EXAMPLES 22~25 19 These catalysts illustrate that pellets and tab-lets of Ticl3AA "supported" on sodium chloride, olefin 21 polymerization catalysts, can be prepared accarting to the 22 technique described in Examples 1-3. Also, after pr~paring 23 a mat as in Example 1, the matted catalysts can be subse-24 quently shaped by extrusion, briquetting or tableting, as degc~ibed earlier. Table 6 summarizes this datfl.

27PELLETS OF NaCl "SUPPORTED" OLEFIN
28P~LYMERIZATION CATALYSTS
29 Example Catal st PTFE Needle Dimension,mm No. ~ ~ Os Gms. Wt.% ~ a b 31 22 TiC13AA 9 0.1 1 10 2.68 2 32 NaCl 0 9 33 23 TiC13AA 9 Ool 1 22 0.15 2 34 24 TiC13M 7 0O1 1 10 2.68 2 NaCl 2 9 36 25 TiC13AA 7 0.1 1 22 0.15 2 37 NaCl 2.9 li~hter 38 1 colore ~ 7()~

2 The catalysts of these examples were prepared ac-3 cording to the technique described in Example 3, and illu8r 4 trate that tablets of TiC13M -olefin polymerization cata-lysts can be prepared having various dimensions, where the 6 tablets described in these experiments are as illustrated.
7 The data summarizing the properties of these catalysts is 8 compiled in Table 7.

10TABLETS OF TiCl3M OLEFIN

12 Example Catalyst PTFE Cork Dimensions, mm 13 No. gmsO ~__. Wt~.~io Borer a _b 14 26 9 9 Ool 1 No~l 3 27 9.9 Ool 1 No.6 12 16 28 9 9 O o l 1 No.l 3 S
17 29 9.9 0.1 1 No.6 12 5 1~ Tablets of Ticl3M "supported" on MgC12~ useful as olefin polymerization catalysts, can be prepared accord-21 ing to the technique described in Example 3. These experi-22 ments illustrate that catalysts having variou~ concentra-23 tions of titanium trichloride on magnesium chloride can be 24 shaped into tablets of various dimensions according to a technique described in Example 3. The data ls summarized 26 in Table 8.

1~ ~ 7~

2TABLETS OF MgCl "SUPPORTED" TlC13 3OLEFIN POLYMER~ZATION CATALYSTS

4 ExampleCatalYst PTFE Cor~ Dimension~ mm No. MateriaI gms. gms. wt.% Borer a b 6 30 TiC13AA 5 O.l 1 No.l 3 7 MgC12 4-5 8 31 TiC13AA 5 O.l 1 No.6 12 9 MgC12 4.5 32 TiC13 5 O~l 1 No. 1 3 5 11 MgC12 4.5 12 33 TiC13 5 O.l I No. 6 12 5 13 M~C12 4.5 l$ In the case of olefin polymerization catalysts, 16 the polyolefin pr~duct has a morphology very similar to the 17 catalyst it3elf. Thus, an added benefit and part of this 18 i~vent~on, i~ addition to the easy handleability of the 19 catalyst, i8 that the product has a predetermined form that 20 i8 also easily handled. In the case of catalysts that have 21 been mechanically shaped to a certain form, products, having ~2 a ~imilar form, will exhibit additional attractlve proper-23 ties- Thi~ phenomena is well illustrated by Examples 34 and 24 35 where, in Example 34, TiC13M catalyst which has not ~een ~5 treated with PTFE was used to polymerize propylene at 6$C.
26 for ~ hours at atmospheric pressure ~o yield polypropylene 27 powder, irregular in shape, having dimensions of O.l by ~.1 a8 mi~limeter- By contrast, in Example 35, pelletized TiC13AA
2~ prepared according to Example 2, is used to polymerize propylene to form pellets of polypropylene which, subsequen~
31 to polymerization, are then treated with alcohol to remove 32 the catalyst residue.
33 The total ~equence of catalyst and polymer forma-34 tion is well illustrated in the drawing previously desc$ibed 11`~'70 ~ 6 1 where in bottle No. 1 TiC13AA i9 seen to be a finely divided 2 powder. This material, which has bee~ ballmilled with 2 3 wt. ~ Teflon, is seen in bottle No. 2 to have the shape of 4 an irregular mat. In bottle No. 3, pellets of dimensions 1.8 by 2 millimeters are evident, as a result of "extruding"
6 the mat. Polypropylene pellets, 7 by 8 mil~imeters, are 7 formed from the catalyst pellets and are ~hown in bottle 8 No. ~, which, after treatment with alcohol, yield clear 9 white polypropylene pellets which have dime~sions 7 by 8 lQ millimeters shown in bottle No. 5. It is understood that 11 catalyst pellet~ or tablets of different shape or sl~e will 12 form similar protucts where the polymer product is a repli-13 cate of the çatalyst. This, to the inventor's knowledge~
14 is the first instance where, in the case of polyolefin catalysts, polyolefln products are formed in a finished 16 shape in the reactor. The data is summarized in Table 9.

18POLYMER FROM SHAPED TiCl~ CATALYST
19 Example Polypropylene Typical Particle 20 No. Catal~st Shape Dimensions, mm 21 34 Ticl3M Irregular 0.1x0.1 22 35 Pelletized Pellet 7 x 8 23 TiC13M

Examplçs 36-38 illustrate that shaped eatalyst 26 par~icles containing additional reagent~ (promoters) may 27 be prepared by a technique described according to Examples 28 1-3- Thus, TiC13 catalysts containing either ethylaluminum 29 dichloride or aluminum trichloride can be shaped wit~ addi-tional reagçnts such as isopentyl ether and TiC14 (Example 31 36~ to TiC13 containing ethylaluminum dichloride can be 32 treatet with fibrillating PTFE and normal pentyl ether, ac-33 cording to Example 37; or catalysts containing TiC13 a~d 34 aluminum chloride can be treated with iqopentyl ether and ,~ I f'~,/t' ~ 17 1~ ~.7(~96 Teflon to form a mat according to Example 38. The data are summarized in Table 10. Once a mat is formed, catalyst shaping is a matter of the mechanical expedient available or the shape desired.

SHAPED PROMOTED CATALYST PARTICLES

Example Additional PTFE Catalyst No. Catalyst (gms) Reagent (gms) g~s wt.~ Shape 36 TiC13 0.23 (i-C5Hl1)2(l) 0.2 2 Mat AlC13(9) TiC14 (0.4) 37 TiC13 0.1 EtAlC12(9) (n-C5Hll)2O(1) 0.2 2 Mat 38 TiC13 0.05 3( ) (i~C5Hll)2(l) 0.2 2 Mat X

Claims (12)

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE PROPERTY
OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. A method for forming shaped, solid catalysts which comprises the steps of mixing solid catalyst particles with a fibrillatable polytetrafluoroethylene; mechanically shearing the mixture to form a mat of catalyst particles entrapped in a fibrous network of the polytetrafluoroethylene, and mechanically shaping the mat to a plurality of particles of a predetermined shape and size to provide shaped catalyst particles of uniform size and shape.

2. The method according to claim 1 wherein the mixture of solid catalyst particles and fibrillatable poly-tetrafluoroethylene contains from about 0.01 wt. % to about 5 wt. % of a fibrillatable polytetrafluoroethylene.

3. A process according to claim l wherein the catalyst particles and fibrillatable polytetrafluoroethylene are mechanically ground for from about 5 to about 30 minutes until the polymer fibrillates, and the catalyst particles are entrapped in the fibrillated polymer, yielding a mat of the mixture.

4. The method according to claim 1, wherein the catalyst particles are a titanium halide catalyst.

5. The method according to claim 4 wherein the titanium halide is a titanium chloride.

6. The method according to claim 5 wherein the titanium chloride is represented by the formula TiClx, where x has a value from 2 to 3.5.

7. A method of preparing shaped Ziegler-type, ti-tanium chloride-containing catalysts of uniform size and substantially cylindrical shape, which comprises the steps of mixing a flbrillatable polytetrafluoroethylene powder with catalytically active catalyst particles such that the resulting mixture contains from about 0.01 wt. % to about 5 wt. % of the polytetrafluoroethylene; subjecting the mix-ture to mechanical shearing forces for a time sufficient to cause a fibrous mat to form entrapping the catalyst particles herein; and thereafter shaping the mat to produce shaped active Ziegler-type catalysts.

8. The method according to claim 7 where the Ziegler-type catalyst has the formula TiCl3.xAlC13, where x has an average value of from 0.01 to 1.5; or TiClm.xAlRnC13-n, where x has an average value of from 0.01 to 1.5, m has an average value of from 2 to 3.5, n has an average value of from 0.01 to 3, and R is an organic radical.

9. In the process for polymerizing alpha-olefins comprising contacting an alpha-olefin with a Ziegler-catalyst system of a titanium halide component and an organic aluminum cocatalyst component under polymerization conditions, the improvement which comprises using, as the Ziegler catalyst system, catalyst particles which have been a) mixed with a fibrillatable polyolefin; b) formed into a malleable mat by mechanical shearing forces to entrap the catalyst particles in a fibrous web; and c) shaped into a plurality of particles of uniform size.

10. The process according to claim 9 wherein the alpha-olefin is propylene.

11. The process according to claim 10 wherein the mixture with the catalyst particles contain from about 0.01 wt. % to about 5 wt. % of the polytetrafluoroethylene.

12. The process according to claim 10 wherein the Ziegler catalyst system has the formula Ticlm.xAlRnCl3-n, where x has an average value of from 0.01 to 1.5; m has an average value of from 2 to 3,5, n has an average value of from 0.01 to 3 and R is an organic radical; or TiC13.xAlC13 where x is as previously stated.