Note: Descriptions are shown in the official language in which they were submitted.
.
1 Polymerization ~atalysts especially olefin
; 2 polymerization catalysts (Ziegler) often have a wide particle
3 5~ze distribution (P.S.D.). It has been found that the catalyst
- 4 particles provide "templates" for the formation of polymer
particles; the catalyst particles themselves must be the same
-6 shape as the desired final polymer powder shape, desirably with
7 a relatively narrow particle size distribution. Conventional
; 8 high molecular weight polymer powders made with usual catalysts
9 have a wide P.S.D. This property makes the resulting polymer ;
powder very difficult to handle. A technique that narrows the
11 P.S.D. of catalysts can narrow the P.S.D. of resulting
12 polyolefins and consequently greatly increase their value by
' 13 virtue of the improved economics of manufacture. Further in
;¦ 14 order to obtain larger powder particles, the catalyst particles
¦ 15 themselves should possess a mean particle diameter of at least
16 10, preferably at least 20 (most preferably at least 35) microns.
17 The stereospecific polymerization ofO~-olefins such
18 as propylene is well known in the art. Polypropylene resin has
`¦ 19 become a well-established plastic in the world market.
l 20 Polypropylene powder sales are also increasing rapidly and, at
;l 21 the present time, are increasing more raLpidly than sales of
22 polypropylene pellets. The popularity of the polypropylene
~. .
23 powder derives~ at least in part~ from the rapidly expanding
24 use of filled grades of polypropylene, particularly glass- or
talc-filled grades.
26 Most customers demand that polypropylene powder provide
. .,
27 all of the resin quality normally obtainable in pelletized
- 28 products and, in addiCion, that the powder possess the qualities
~1 29 of good ~lowability, low fines content, and no "clods" (large
aggregates of particles). A reasonably high bulk density is also
31 desirable.
32 The P.S.D. of catalysts can be made narrower by
~' '" 2
3~i~
1 controlled growth of catalyst particles. Polyolefin P.S.D.
- _ 2 csn be ~ade narrower by agglomeration and compaction of
. ~ . : ,. .
` 3 polymer particles. Adhesive binders have been used in this
` 4 latter technique; however, adhesives do not unction well in
t 5 catalyst compaction since they poLson the catalyst active
~ .
l - - 6 sites. U.S. Patents 3,838,064 and 3,838,092 describe a
; 7 technique of eliminating dust from inert powders.
8 In its most preferred aspect the invention involves
9 worXing small quantities of PTFE powder with catalytic
..~
10 (preferably Ziegler catalysts, e.g. TiC13) fines, e.g. 10 `
11 microns in mean particle diameter or smaller, to result in
12 a catalyti~ally active particle more than 10 microns in mean
13 particle diameter consisting of a plurality of catalytic
14 fines in a web of submicroscopic fibers oE PTFE. ~`
Prior to the present lnvention, it has not been
16 practicable to meet the narrow particle size distribution
17 ob~ectives~
18 A catalyst having a narrow particle size distribution
l9 can be produced, but the product, especially from a ball milling
, ...................................................................... .
I~i 20 step, has many very tiny catalyst fines or particles, e.g. less
,~i 21 than 1 micron up to 20 microns of mean particle diameter.
~'j 22 Such a catalyst product can be sieved to increase the
23 mean particle diameter by separating the larger par~icles from
,. "
24 the smaller, but since there is no utility for the discarded
fines, this approach has not heretofore been attractive. The
26 present invention allows the discarded fines to be used per
27 se for producing larger particles. Or sieving can be eliminated
28 and the larger and smaller particles together are worked to
29 eliminate-substantially all cataiysts fines having a mean
particle diameter of 10 microns or less.
31 The present lnvention provides a process whereby a Ziegler-
32 type catalyst of larger particle size ~e.g. 10 to 1,000,
, ~;
~ - 3 -
j:: .,
'',.'' :
~',.,:' ~ '' ; ' ""'
':: ~: . ,
,:,,. /
6~3~3
: `` f preferably 20 to 200 microns, most preferably 20 to 50 microns,
2 average mean particle diameter) can be produced, which consists
3 of particles having a relatively narrow particle size
, ~
4 distribution.
The production of Ziegler-type catalysts from TiC14 can
6 be accomplished with several reducing agents, each of which
7 produces a reduced TiC13 .nAlC13 catalyst. The value of n
8 varies with the reducing agent employed. ~hen diethylaluminum
9 chloride tDEAC) is used as the reducing agent, n will range -
~- 10 from about 0.15 to about 0.50, and usually will be from 0.28
11 to 0.43, although theoretically n could be 0.5. Use of ethyl
.
12 aluminum dichloride (EA~C) results in a value of n from 0.3
13 to 1Ø The catalyst having a higher AlC13 content usually -
14 wlll have a lower catalyst activity (expressed as grams of
polymer product per gram of catalyst employed). U9e of an
16 excess of redllcing agent provldes a catalyst of lower AlC13
", "
! 17 content, but the particle size is smaller. But any suitable
18 reduction technique now known to the art or subsequently
l9 discovered can be used~ since the reduction step per se is
not at the point of novelty.
21 It is understood that the concept disclosed in this
.. . . ..
22 patent appllcation will apply to formulations of catalyst
23 such as: TiC13.xAlC13 where x ranges between 0.01-1.5;
24 TiClm.xAlRnCl3_n where x ranges between 0.01-l.S~ m ranges
between 2-3.5, and n ranges between 0.01-3, and R is an
26 organic radical such as CH3, C2Hs~ C3H7 etc., or other
27 organic radical that normally is know~ and described by
28 Mole and Jeffreyl; MX'm.XM'RnX'3_n where M are metals of
29 groups IIIB, IVB and VB of ~he pe~iodic table, and M' are
elements of groups lA, IIA and IIIA of the periodic table~ X
31 and X' are elements of $roups VIA and VIIIA of the periodic table,
32 and m, x~ and n vary as described above.
. ~ .
33 T. Mole & E.A.Jeffrey~ "Organoaluminum Compounds", Elsevier,(1972)
_ 4 _
, ~~
6~3~L~
1 The PTFE of choice for this lnvention is obtained
2 from E.I. DuPont de Ne~ours & Co.~ Wilmington~ Delaware
3 19898, as TEFLON K. It is a white powder; type 10 has been
4 found suitable for use with the Z~egler-type catalysts.
Yery generally, the process used to obtain the enlarged
6 catalytic particle consisting of catalyst fines in a TEFLON K web
7 comprises adding the TEFLON K to the catalyst powder, mixing to
8 form a homogeneous blend, and working this blend to form a fiber-
9 web of TEFLON K having a particle size larger than lO microns mean
,
10 diameter and containing many catalyst fines having a diameter of
11 less than lO microns mean diameter.
12 For best results, TEFLON K, Type lO, should always be handled
13 at or below room temperature (20C) so as to avoid further agglom-
14 eration of the PTFE particles. It should be spread as evenly as
15 possible over the catalyst to be treated, such as by sprinkling or
16 by continuously adding the PTFE to a continuous plant process, thus
17 avoiding the batch addition of the PTFE which increases the likelihood
1~ of further agglomeration of the PTFE.
19 A homogeneous mixture is necessary if the fiber-web is to
2~ pervade the entire mixture. Dry mlxtures can be prepared with most
21 mixers but it should be noted that violent mixing such as with
22 Warlng Blendors, hammermills, or intensi~ier bars seems to initiate
23 fibrillation and this is essential if tumbling is the only other
, . . ,~
: 2~ working step.
; 2s Working is the application of a compressive shear to the mixture ;~
26 of TEFLON K and the catalyst powder to be treated so that the fiber-
..
; 27 web is developed within the mixture.
. ..................................................................... ..
23 The working action applies a compressive shear to the mixture,
29 but the terms troweling and smearing are also descriptive of that kind
;., .
. 3~ of action. In the laboratory, this can be done with a spatula, a
mortar/pestle or a small ball mill. In the plant, mullers, ball
~;: ;2 mills, slow-turning mixers or blenders, screw conveyors, spray driers
^ and many more devices ~lill do some or all of the fibrillat;on. ~
* Trade Mark _5_ -:
. .
,, ,
- 1 The working action just described must also be a slow action.
2 Another consideration is that the mixture should be low in water -
., .
3 content so that moisture does not serve as a lubricant to interfere
4 with the working action.
One of the most important considerations is an adequate
6 working temperature. The fiber-web will not form below 20C nor
7 will it survive above 320C. A common working temperature is 100C
8 but with many materials it can be lower as determined by experimen-
g tation.
.; ~ .
.i 10 ~ Any specific mater;al to be treated will seem to have a
11 minimum working temperature below which no obv;ous f;br;llat;on occurs.
12 Above this temperature there seem to be useful combinations of
; 13 work;ng cond;t;ons, dosage o~ TEFLON K and temperature. Stated a
i 14 bit d;fferently, w;thin l;m;ts, work;ng is faster and more effective
. 15 with
16 . higher temperatures,
~; - -17 . higher dosages of TEFLON K, and
~, - 18 . better work;ng act;on.
19 Well worked mixtures with TEFLON K w;ll show eY;dences of
f;br;llation such as an increased cohesiveness, an obv;ous change in
21 texture, and mater;al on a spatula w;ll exhib;t "whiskers" hanging ~
." ' :
22 over the edge. Incidently, these "whiskers" seem to be web fragments
23 made v;s;ble only by their trappecl dust.
`; 24 The first stage of fiber development, f;ber ;nitiation, is the
. ~ .
; ~ 25 most d;ff;cult and occasionally requ;res a different working act;on.
.~ .................................................................... .
~ 26 A brief treatment of the m;x in a hammerm;ll, Waring Blendor or
~,..................................................................... . .
,~ 27 most any high-speed, intense mixer does this fiber ;nitiation,
~ 28 presumably by elongating the TEFLON particles by impact. This kind ;
; 29 of pre-treatment ;s optional though generally helpful to most
,, .,.: .
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.....
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,.,;, .. ~. .~. ... . - .
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1 succeeding working steps, but it is frequently essential ahead of ~-
2 working by tumbling only.
3 The ~osage of TEFLON K will be higher in laboratory work than
4 it wi11 be later in the plant. The method of treatment will be a
- 5 matter of choice but it should generally follow the method of plant
6 production i~ possible, i.e., wet or dry treatment, etc. Start
7 out with a high dosage such as 1/2% or even 1% TEFLON K if this is
8 the first trial. The dosages referred to are the weight percent of
9 resin in the dry material being treated. Mix the powdered TEFLON ~`
; 10 K with the material in a Waring Blendor for a couple minutes. Stop
' 11 the blender occasionally to get the powders down into the blades i~
12 necessary. Heat the mix to 100C and work as aboveO
13 After the first trial, conditions should be altered to produce
14 the product desired.
A small laboratory ball mill can be a convenient working device.
~ 16 Fill the mill about 75-85% full of balls and mixture to minimize the
"
' 17 cascading of the balls. The mill and contents can be preheated and
18 will hold the heat well, or heat lamps may be used. This device
19 makes work with toxic products relatively safe and easy since the
material will be enclosed in the mill wh;le it is being worked.
21 Laboratory production serves to give experience with,the process,
22 provide an idea of the kind of product that can be produced and these
23 preparations can be tested for usefulness. Further, it is possible
-24 to note temperature and dosage ranges which may be guides to initial
~- 25 plant production.
:
26 In addition to the previously mentioned equipment, spray dryers
27 with either nozzles or spinning discs will do a good job of fibriilation.
28 Additional working with a hot blending operation has proven beneficial
,.
29 to some treatments.
_7_
, . ' ' .
,~ r
;,` ~ '
'~L~ L3~
1 Extruders also can be effective working devices. Lodige ;'
2 blenders have done well also, but be aware that some large sizes
3 have air pressurized bearings which levitate the mix by aeration ,`
4 so that it cannot be worked.
Since this process is somewhat equipment dependent, it is
6 recommended to move rather quickly into plant scale equ;pment.
7 Plant scale production'generally requires a lower dosage because
8 the larger mass'of material being handled adds to the compressive
9 shear action. Since a higher'dosage than necessary may lead to
... . .
,' 10 greater cohesion and reduced flowability, it is well to start'with
r,.' j`~~__ .
;' 11 a half to a fourth of the laboratory dosage. Should the treatment '
~'- 12 produce a poorly flowing product, it may usually be blended with
13 more product to give a desirable finished product.
L~' ' 14 It is sometimes desirable to prepare a concentrate of powder
and TEFLON K at from, say', four to ten times the optimum dosage,
. ..
16 and then blend it off to the desired -Final concentration in one '
17 massive dilution or by a gradual dilution. This is referred to as
' ~ 18 a master blend technique.
.; ' 19 ' Fibril initiation is easier at these higher concentrations of
TEFLON K. This method of treatment also permits an easier fibrilla-
,'i,.~ . .
i,jl 21 tion of some difficult materials by starting the fibrillation at
'; 22 these higher concentrations. This is also a means for initiating
~' 23 fibrillation with temperature and working speed being short ofi ~` l
' 24 optimum.
Care must be exercised to stop the mechanical working of the
'i 26 master mix or concentrate before it becomes too fibrillated. If not,
j:~ 27 further blending may become quite difficult.
''' 28 An interesting advantage of the master blend method is that
; 29 the total working time can frequently be less than with the normal
... . .
; .- .
~ 8-
.~ .
. ~ . .
~, :
,. ....... ...
. .,
;......... - ~ .. . ,
r,~
3~
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1 working procedure. Time can be saved since fiber initiation is
2 much more rapid at the higher loading of TEFLON K in the master
.. ~ ,
3 mix. Also, much less time is needed to blend to the final dilution
- 4 than to have worked the whole charge from the start.
This master blend method also permits a flexibility in the
6 use of working machinery by using the equipment with the best working ;~
,, . ~
7 action for the master mix and then using less efficient equipment
8 for blending it off.
9 It is possible to change part;cles of TEFLON K particle control -
additive into fibers by passing a proper mixture through a region of
11 turbulent gas flow. This has been accomplished by use of orifice
12 plates, Venturi tubes, etc., and it has been done with various
13 addition methods, including spraying a fine mist of diluted TEFLON K,
14 Type 20 into the hot gas stream which was carrying the powder to be
processed. The Melt-Blowing process of Exxon Research could be used
16 for mixing.
,:~ . . .
17 The Invention is further illustrated by the following examples:
18 Example 1
19 TiC13-0.33AlC13 produced by the reduction of TiCl~ with aluminum
:,.,
~ 20 and then dry ballmilled was obtained from the Stauffer Chemical Company
,.
,;; 21 as TiC13-AA or TiC13-A and was yround or ballmilled in the presence
i 22 of dry TEFLON K. During the ballmilling the catalyst surface area
23 was increased with concomitant increase in catalyst activity, but
., . ,~
~ 24 the catalyst was not poisoned by the inert TEFLON K. The catalyst ~
,,; . , .
~ 25 fines that normally lead to a wide P.S.~. are in this process, held -
,,,.~ , ~:.1
; 26 by submicron strands of Teflon. The polymer made with these catalyst
27 particles will also have a narrow P.S.D.
28 TiC13 0.33AlC13 that has been ballmilled and otherwise treated
29 to improve its activity and stereospecificity, e.g., ether/TiC14
,, ,~
. .; _9
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. .
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.. ' ... .. , . . : .... ...
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1 treatments, was also ballmilled with dry TEFLON K to agglomerate
2 the catalyst part;cles in a web of Teflon f;bers.
3 The results are summarized in TABLES I and II following at pages 11-13. ;c
4 It is also understood that materials other than Teflon or special
; 5 formulations of polytetrafluoroethylene will serve to entrap the
6 catalyst particles as disclosed here, as well as other polymeric
7 materials that fibrillate on mechanical treatment as described above.
8 Thus polymeric materials such as polyethylene, chlorinated Teflons
9 and other polyolefins at elevated temperatures may form polymer webs.
-~_ 10 It is furthermore clearly envisioned that polytetrafluoro-
11 ethylene treated with other materials such as Lewis bases or Lewis
12 acids can be used in the above described treatment, thereby accomplish-
13 ing two or more objectives, agglomerating catalyst particles and
..
14 activating the catalyst.
All above descriptions are thought to be unique in that they
16 modify the nature of the catalyst, which in turn modifies the nature
17 of the product made from such a catalyst.
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~. 1 It is to be noted that in the above TABLE I the catalyst ;
.~ - 2 described in Experiments Nos. 32 2 and 32-3 as STP is a special ~ .
3 experimental catalyst which is essentially a TiC14 which has been
4 reduced in a diluent with an aluminum alkyl chloride and subsequently
: 5 treated with the indicated amount of ether, follcwed by a treatment -.:
6 with the indicated amount of TiCl~. This catalyst is e.:ceptionally
7 active and it is highly advantageous to be able to form the relatively ...~ - 8 large active particles of the invention from ~he small micron size
; 9 fines of this particular catalyst.
;; 10 It can be seen from an examination of the data in these . .
. 11 TABLES I and II that dramatic changes in the particle size o~ the . .
. 12 catalyst and the polymer resulting therefrom can be accomplished :~
13 without appreciable loss of catalyst efficiency. '
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- ~6~
SUPPL13~1ENTA~Y DISCLOSURE
1 In yet another aspect, the invention involves
- 2 working small quantities o PTF~ powder with supported
3 catalytic (preferably supported Ziegler catalyst, e.g.
4 supported TiC13) fines, e.g. 10 microns in mean pa~ticle
diameter or smaller to result in a supported catalyti-
cally active particle at least more than 10 microns in
7 mean particle diameter consisting o a plurality of
8 supported catalytic fines in a web of submicroscopic
9 fibers of PTFE~ ` !;
The generalized problem of the ]ack or dsgired part-
11 icle size uniformity that is obtained when one ballmi]ls
12 a 2iegler catalyst was described in detail above. The
, .~
:~ 13 det~liled discussion and the s~ec.ific examples were
14 clirected primarily to a ~ituation in which the 2i.ecl1er
~' 15 catalys~ was a cocrystallized TiC13 ~ith aluminum chloride
, . . . ..
16 which had been activated by extensive ballmilling.
~, 17 j~ ~nother species of ZiegIer catalyst ~hich was not t
s I . ~ .
18 extensively discussed in the parent application is that
"~ 19 which is referred to for convenience as a supported
~...................................................................... ,~
~ 20 catAlyst. For the purpose of this application, the
;l 21 term "supported catalyst" does not include materials
; 22 in which the support shape is predetermin~d ln advance
23 and the active catalyst, e.g. TiC13 is merely deposited
' 24 on the surface of the prede~ermined shape. Examples of
;~ 25 that would include preshaped particles, such as spheres
l 26 which were manufactured to have the requisite shape and
`~ 27 simply were unchanged in shape by the catalyst deposition
`l 28 process.
-' 29 For the purpose of this invention, the term "support"
'~ 30 in the context of "supported ~iegler catalyst" is meant
31 to apply to inorganic salts of halogens ~hich can be
!: .
< 32 cocrystallized with an active transition metal halide, ,~
:~ , ' :
. ,' :, .
1 e.g. TiC13 catalyst component by extensive grinding and
2 milling of said lnorganic halide salt support with
3 titanium chloride. Such titanium chloride can either be
4 in the reduced sta-te, e.g. TiC13, or it can be in the
5 orm of TiC14 which is subsequently reduced either during L
6 the milling step or subsequen~ to the milling step just
~,.
~ 7 prior to activation by a cocatalyst for polymerization.
;~
8 In any event, the resulting ca-talyst is a "sup~or~ed
9 Ziegler catalyst" ~hich forms the subject of this inven-
10 tion. It is extensively milled, ground or otherwise r,
11 subjected to intense physical activity so that a wide
12 range of particle size distribu-tion is obtained, similar
13 to that which i5 obtained when the Ti¢13 cocrystallized
r t s~
14 with aluminum chloride is ball milled.
Thus, it is the inventive scope o thi~ a~pllcation
16 that Ziegler catalysts which are "supported" by inorganic
17 halogen sal-ts can also be treated with the fibrillatable
18 polytetrafluoroethylelle materials as described in the
19 parent application and later herein to overcome the !-
20 problem of fines and wide particle size distribution. l~
21 In the disclosure above, the production of Ziegler-
22 type catalysts from TiCl~ was described as being accom-
23 plished with several reducing agents, each of which
2~ ~roduced a reduced TiC13-n~1C13 catalyst. The value of
25 n varies with the reducing agent employed. When diethyl- 1
26 aluminum chloride (DEAC) is used as the reducing agent, -`
,i,. . .
27 n will range from about 0.15 to about 0.50, and usually ;~
28 will be from 0.28 to 0.43, although theoretically n
.
29 could be 0.5. Use of ethyl aluminum dichloride (EADC~
results in a value of n from 0.3 to 1~0. The catalyst
31 having a higher AlC13 content usually will have a lower
32 catalyst activity (expressed as grams o polymer product
- 16 -
; .,, . .. . .: :
3~
1 per gram of ca alyst employed). ~se of an excess o
2 reducing agent provides a catalyst of lower AlC13
3 content, but the particle size is smallex. But any suit-
4 able reduction technique now known tv the art or subse-
. . .
quently discovered can be used, since the reduction step
- 6 per se is not at the point of novelty. ~ i
7 It was described above that normally the reduction
; 8 of TiC14 results in a cocrystallized TiC13 with aluminum
: 9 chloride. This is true with most reducing agents, includ-
; 10 ing aluminum, magnesium and titanium metal. There is at
11 least one exception to this general principle. It is
12 that when aluminum trialkyl, where the alkyl groups range
13 ~rom 2 carhon atoms to about 5 carbon atoms in lenyth ;
14 and are preerably aluminum triethyl, e.g. TE~L, the
; 15 reduced products are primarily TiC13 and aluminum alkyl
16 dichloride. Although the aluminum alkyl dichloride is
17 capable of cocrystallization with the TiC13 and some
i8 of such cocrystallization takes place, the influe~ce
19 of diluents, third components and cocatalysts will
- 20 often result in the removal of such aluminum alkyl di-
2~ chloride, thus leaving a catalyst which is simply TiC1
.. ,; , .~ . i 22 alone.
23 Forimost purposes, the reduc,tion step with TEAL for
;' 24 instance is so rapid that the resulting TiC13 is too
! ' ~ , . . .
; 25 small to be effectively utilized. If those small part~
~; 2~ icles can be conveniently collected, the prccess of the
27 instant invention would permit them to be agglomerated ~-
r
; ~ 28 into larger catalyst masses which would be more suit- s
; 29 able for commercial use.
However, when the TiC13 is on the support, i.e. the
;~- 31 inorganic metal halide of the invention, that support
.,.. ~ ,
7`~.'!` 32 provides sufficient structure and size so that even the
:,j~. . .
~ 17 -
! :' , .
~ti13~
1 TiC13 without being cocrystallized with the aluminum
2 chloride can be effectively utilized. Thus, it is ~o be
3 emphasized that the scope of the invention is not re$tric-
4 ted to just TiC13 catalyst components which are cocry-
stallized with aluminum chloride, but is of scope
6 adequate to comprise TiC13 which is supported upon an
7 inorganic metal halide. In most situations, the TiC13
8 will b~ cocrystallized in some manner witll the support
t. ~
9 halide. --
10 The invention is applicable to Ziegler catalysts o~ 1
11 o~her transition metals such as ~anadium, molybdenum, ~`
~.
12 zirconium, and the like.
13 Surprisingly, aluminum chloride per se is not a
14 particularly good support material. But it.can be
15 blended-with other outstanding support materials in
16 minor proportions, e.g. 0.1 to 40 weight percent, prefer-
17 ably 10 to 35 weight percent, and most preferably about
18 15 to 25 weight percent in order to modify the properties r
19 of the fundamental support material.
In general, the inorganic metal halide salts will
21 be the metals of Groups IA, II A and B and III A of the
22 Periodic System. Examples include aluminum, sodium,
`23 lithium, boron, gallium, berylliu~ magnesium, zinc and
24 cadmium.
Examples of suitable halides include MgCl2, Mgsr
26 ZnC12, ZnBr2, NaCl, LiCl, AlBr3, AlI3, CaC12, MgI3-
27 Manganese chlorides are also utilizable.
28 During ballmilling, any of these inorganic support ~ -
29 halides are capable of cocrystallizing with the titanium f
inetal halide. This ability of cocrystallization o~
31 titanium chloride with other halides of Groups II and
32 III is known to the art and has been described at an
- 18 -
.,. . ~ .
.,, - . ,
36~3~
- l early date, such as in U.S. 3,128,252.
2 It might be well to touch on the rationale of
3 utilizing a support for titanium trichloride~ Generally,
.
4 the primary reason was to increase their activity since
it could be made dependent on the surface area of the
6 support. And it was known that numerous supported
7 materials had great activity. And actually, such sup~
8 ported Ziegler catalysts are extensively used in ethylene
. t: ' ' .
~- 9 polymerization processes. ;-
~0 Nevertheless, they have not been used in commercial '~
11 polypropylene processes since even though they have high
12 activity, the stereoregularity of the polypropylene pro-
13 duced ha.s not been sufficiently lli~h to permit competitive
14 commercial opera~ions. However, in recent years great
~;~ 15 strides have been made in overcoming the initial lack of ~,
; i.: .
16 stereoregularity.
~, 17 The most attractive supported catalysts of the nature
18 described herein have been obtàined when the support
.. . . ,, ............................... ~
l9 ~aterial is activated by ballmilling. And the stereo-
specificity of the ballmilled supported catalyst is
21 improved considerably by.the presence of various highly
22 criti.cal third components, usually Lewis bases. Examples
23 of patent li~erature which describe ballmilling of TiC14
, ~ ~
'!`," 24 or TiC13 with inorganic metal halide materials as supports
25 ~ include German Patent DT 223-0672, German Patent DT 223-
~; 26 0728, German Patent DT 223-0752, Belgian 805,264, German ;~
~; 27 DT 223-5033, Japanese 4735076.
`~ 28 In general, the supported catalysts which are in-
.,à" , 29 cluded within the scope of this invention are prepared by
introducing a Group I A, II A and B or III A metal halide,
31 e.g. magnesium chloride is ~specially preferred, into a
32 gri~in~ apparatus, preferably a steel ball mill. Then
'i .
.", , , ~.
,.. : . ~ , , . . , . . - . . -
3~L~
..
,~ 1 TiC14 in a ratio of about 0.05 to 1 based on moles of
~ ~ support material is also introduced into the mill.
', 3 Depending on whether'the catalyst is to be used for
,~ 4 polyethylene or polypropylene, a third component is
.,' 5 usually introduced into the mill. These materials are ,,
,,, 6 then ground together extensively for at least several
,'; 7 houxs until the supported catalyst is in either a-
~ 8 relatively high state of activation or ready to be , ~`
i,,,
,' 9 additionally reduced by a conventional reducing technique.
10 During this grinding process, very fine particles ,
', 11 of supported catalyst are,produced. These can be agglom- i
~'~ 12 érated and made into larger particle uti]izing the tech~ `
,,' 13 nique of the invention as described hereinaEter.
; 1~ But it is to be emphasized that the catalyst formu- ,
,,,' 15 la~ion's of the lnvention include those described at ,' ,
~ 16 length which fall in the c]ass of supported Ziegler ~ ','
,,~,,. - . .
17 catalyst on certain metal halides. And thereEore, the
.
,, 18 catalys~ which can be agglomerated utilizing the tech-
';, , 19 niques described herein is not restricted to where the
'',` 20 TiC13 is previously cocrystallized with only aluminum '
~ 21 chloride. But it also includes that whole subclass of ,
', 22 catalysts where the.re is some interaction between the
~ 23 TiC13 and~the metal halide support. That is the more ,
'' , 24 likely situation to occur in the support catalyst area. j ~
~, , 2'5 It is also hypothesized with some stron~ theoretical ,, r
26 support that the TiC13 is actually cocrystalliæed with
~,' 27 many of the metal halide supports,in a manner completely ,~
',;, ~ D:
28 analogous to the manner in which it is cocrystallized ~,
;,,,'~- 29 conventionally with aluminum chloride. Of course, alumi-
~l 30 num chloride may constitute a component of the support.
i`'-`"' - 31 In that case, it would be expected that a portion of the
~'~ 32 TiC13 associated with the support will ~e cocrystallized
. . " ~, . .
~ ~ - 20 - '' ' ~
..c~
."
1 as indicated in the parent application. However, that-
2 aspect alone is an unduly restrictive concept of the
3 invention presented herein.
4 It must also be additionally emphasized that a
feature of this invention is that a previously cocrystal-
~ i . .
6 lized TiC13 aluminum chloride is very fine particle size
7 will be ballmilled with an appropriate metal halide
8 support material in order to disperse the finely divided
9 cocrystallized particles on the support material. That
resul~ting fine supported Ziegler catalyst is within the
ll scopeTof this disclosure as a material which can be
12 considerably improved by the agglomeration technique of
13 the invention.
,." , ,
14 Fxam ~ ` ~ ;
Twelve yrams of anh~drous magnesium chloride and 1
16 gram of TiC14 are milled in a vibration mill containing
17 80 steel balls having a 12 mm diameter for a time of 16
18 hours. The surface area of the rssulting supported
: 19 catalyst is about 8 m2/gm and the catalyst has a wide
' 20 particle size distribution with a substantial quantity ;~
21 of fines, e.g. materials having a particle size of l0
~ 22,~ microns or less of mean particle diameter.
,i~ 23 This`material is then ballmilled in the presence of
24 a polytetrafluoroe~hylene material obtained from duPont
~i 25 under the tradename TEFLON K. ! . -
.,., j .
26 The catalyst fines are held by submicron strands of
,, 27 the TEFLON K material and therefore the supported catalyst
;;~ 28 has a much narrower particle size distribution e.g. more
29 than 10 P.S.D. than that which would be obtained if no
grinding in the presence of TEFLON K was carried out.
l 31 Example 3
.'!,. . 32 The process of Example 2 is repeated exactly except that
, _ 21 ~
;~ :
3~ ;
;. .. . .
;~ ~ 1 the TEFLON K is introduced at the beginning of the ball-
,~ 2 milling process rather than at the end. The particle
,`~ 3 size distribution obtained is essentially the same. '
' 4 Example 4
' 5 The process of Example 2 is repeated except that the ,
6 titanium compound is the TiC13 0.33~1C13 of ~xample 1.
7 Example 5
,i,, 8 The procedure of Example 4 is repeated exac~ly except
'' ~ g that the TEFLON K is introduced at the inception of the '~;,-
~grinding/ballmilling, rather than at the end of such
~¢~ ' 11 process.
~;~ 12 In the above example, the TEFLON K referred to,
, : .
13 when used as a solid, is available ~'rom thc-~ E.I. duPont
; 14 company, Fluorocarbons Division, as Type 10. It is a
, lS ree flowing,white powder with the following characteris 1"
.`.~.~ ~ I'
16 tics: 1'
. , . , . .
17 ~ Average Particle Size - 500 Microns
18 Bulk Density ' - 450 g/l
19 Intrinsic Density - Z.2 g/ml
Surface Area - 10M2/g ,'~ r
21 Crystallinity - 95% 1' '
22 M;elting Range - 3Z0-340C (608-6~'14F)
23 Solubility - ~j,Insoluble in all CoT~mon
24 , ' solvents
25 Chemical Inertness - Stable to all common ~.
,. ~
~ 26 reagents at ordinary ~'
"',', 27 temperatures. Reacts
~, 23 with alkali metals and
'~j,`, Z9 fluorine or reactive
agents yielding fluorine. 1'
t - 22 -,
: ,
~ . '
.. ; .
