CA2243519A1 - Stable metallocene catalyst systems - Google Patents

Abstract

This invention relates to stabilized metallocene catalyst systems and to methods for their production and use. Specifically, these catalyst systems comprise metallocene, alkylalumoxane and optionally support material wherein the ratio of the aluminum of the alkyl alumoxane to the transition metal of the metallocene used to prepare the metallocene is in the range of from about 80:1 to about 200:1. These catalysts retain their activity and may be used directly in polymerization after storage for up to two months or more at ambient temperature.

Description

W O 97/32!)06 PCT~US97/03486 APPLICATION FOR PATENT

Title: Stable Metallocene Catalyst Systems 10 Fiçld of the Invention This invention relates to st~hili7ed metallocene catalyst systems and to rnP.th~rlc for their pro~ ction and use. Specifiç~lly~ these catalyst systems conl~lise metal~ocene and alkyl~ .u~ e wh~ ein the ratio of the ~ mim lm of the 15 alkyl~ r.~ e to the transition metal of the metallocene used to prepare the catlayst system is in the range of from about 80:1 to about 200:1. These catalyst ~y~lellls retain their activity and may be used directly in polymerization afterstorage for periods of up to two months or more.

20 Bacl~lou-,d A well-known problem RecoGi~ted with activated metallocene catalyst sy~L~I..s is their inability to remain stable and active for more than a few days or hours particularly at high temperatures. Consequently, metallocene catalyst 25 s~ s must be used soon after p~epa,~lion in order to take advantage of their m~cimllm productivity. Using a catalyst ;~""e~ y a~er its production can be ~uite ~liffic~lt particularly on a commercial scale. To date, a~Lt;..,pLs to alleviate this problem have met with limited s lccecc W O 97/32906 PCT~US97/03486 U. S. Patent No. 5,308,817 describes a particular syndiospecific metallocene which, when activated with methy~ mnx~np~ is stable for up to 3 days with good activity. These aged catalyst systems, however, tend to cause polylllG~ n reactor fouling and this tPn~lPn~y increases with inc~c,ased aging 5 time.

U. S. Patent No. 5,393,851 describes a concentrated stock metallocene/alumoxane solution which may be stored for up to 14 days. Before use in poly",c.i~.lion, this solution must be diluted with additional alumoxane.10 Additionally, these col-ce.-Ll~led sol~ltiQn~ must be stored in a relatively cool em,ilo.lllle..l in order to retain activity and there can be an activity loss of from 20 to 30 percent before the solution becomes stable.

The two patents ~ cu~sed above illustrate the need in the art for catalyst 15 ~;,l~.l,s and colllpollell~S that can be stored for long periods oftime. In particular there is a need for catalyst systems that can not only be stored for long periods of time but can be stored at arnbient te"lpe,a~.lres (inr1uding high te--.,~)e.~ res) and can be used directly in polylllc~ ion after storage. This appliç~tion describes an unC~l~P~cle~l~y improved active mpt~llocçne catalyst system that can be stored at 20 high te-"peralure for as much as two months or more. After storage, this catalyst system can be used directly as an Pfficiçnt polymeriza~ion catalyst without ~d~litiQ~l activation.

~umm~y This invention relates to a method for polymerizing olefins comprising poly.. ;~ g one or more olefins under suitable polyrneli~d~iol1 conditions in the ple3e.lce of an active metallocene catalyst system complisi-lg metallocene and an alkyl~ J~.c which active catalyst system has been stored for at least two days.

W O 97/32S~06 PCT~US97tO3486 This invention also relates to stabilized metallocene catalyst systems complising metallocene, alkylalumoxane and optionally support material wherein the ratio ofthe ~hlminllm ofthe alkyl~ n~ c to the transi~ion metal ofthe metallocene used ~ to p~ al e the catalyst system is in the range of from about 8Q: l to about Z00: 1.
5 Atlfliti(~ y, this invention relates to a method for p,ep~i,lg a mef~lloc~ns catalyst system, said method comprising the steps of: (a) co-llbinil~g a metallocene catalyst companent with an alkyl~ - ..Ox ~ wherein the ratio of the ~ min~-m of the alkyl~ f to the transition metal of the metallocene used to prepare the catalyst system is in the range of from about 80:1 to about 200:1; and (b) storing 10 the co,-.l,hl&lion for a time period of at least about two days.

Detailed Des~li,ulion of Plefe,-t;d Embodimentc Generally, the metallocene catalyst systems of this invention comprises 15 metallocene and alkyl~h-moYSlne wherein the ratio of the ~h-mimlm of the allyl~ Y~llp~ to the transition metal ofthe metallocene used to prepare the catalyst system is in the range of from about 80:1 to about 200:1. This catalystsysterm can be stored for at least about two days at relatively high telllpt:l ~L~res without s~ks~nti~l loss in activity. As used herein, "storing" or "stored" means20 allowed to sit without being used as a catalyst system or COIllt)Onell~.

P~c,ably the ratio of the ~IIlmimlm of the alkylalumoxane to the transition metal of the metallocene used to prepare the catalyst system is in the range of from about 85:1 to about lS0:1, more plefel~bly from about 90:1 to about 125:1. The 25 composition may be stored for at least about two days, or up to about 5 days,about 7 days, about 14 days, about 21 days, about 28 days, about 35 days, about 42 da~s, about 49 days, about 56 days, about 63 days, about 70 days, about 77 days, about 84 days or even about 91 days or more.

W O 97/32906 PCT~US97/03486 Preferably the weight percent of metal on the fini~hed catalyst system is in the range offrom about 0.20 to about 1.0, more p,ere.~bly from about 0.25 to about 0.85, and most pr~rt;.ably from about 0.30 to about 0.70.

The temperature during storage may be up to 60~C, p-e~e.ably up to 45~C, more prer~ ~ ~bly ~~ . 'lt tel..pe- ~ re or from about 20~C to about 45~C.
Although the catalyst system may be stored at high ambient te~ )e~LLIres, higherproductivity is likely to be I ~Lailled if the catalyst sytem is stored under the coolest conrlition~ practicable. Thus, the catalyst system may be warehoused outside or only partially sheltered in most Çlim~tes Any suitable container may be used forstorage. To preserve activity, the co~ should be air-tight and the storage atmosphere should be free of oxygen and/or water.

A~er storage, the catalyst system retains at least about 50~/0 of its original productivity, plt;re.~bly at least about 60%, more pl~;rt;.~bl~ at least about 7~%
even more p.t;rcr~bly at least about 75%, even more prc;re,t;ably at least about80%, even more prere.~bly at least about 90% and most p~ r~bly at least about 95 percent of its original productivity, i.e., its productivity when less than 1 day old.
The metallocene and allyl~ -e are preferably combi--ed with a support ei~her before or a~er storage, p~t;re-~bly before storage. For purposes of this patent speçifiç~tion the term "support" is defined as any material upon which metallocenes and/or activators may be fixed. Preferably, the support material is a porous particulate material, such as talc, inorganic oxides, ino-~ ic chlorides and resinous materials such as polyolefin or polymeric compounds. Such materials aregenerally commercially available.

The ,olere"ed support materials are porous inorganic oxide materials, which include those from the Periodic Table of Elem~o-nt~ of Groups 2, 3, 4, 5, 13 W O 97/32~D6 PCTnUS97/03486 or 14 metal oxides. Silica, ~IIImin~ silica~ min~, and mixtures thereof are most~)le~llt;d. Other inorganic oxides that may be employed either alone or in co.~ ;ol- with the silica, ~ min~ or silica-~l~lmin~ are l..~.~..P,- ~, titania,~irco~ and the like.

Any ml~t~lloc~ne may be used in the practice of the invention. A~s used herein lmless o~ lwise in~ic~te(i, "metallocene" in~l-ldes a single metallocene composition or two or more metallocene compositions. Metallocenes are typically bulky ligand tr~n~iti~ n metal compounds generally l epl esellled by the forrnula:
[L]mM~A]n where L is a bulky ligand; A is leaving group, M is a transition metal and m and n are such that the total ligand valency corresponds to the transition metal valency.

The ligands L and A may be bridged to each other, and if two ligands L
15 and/or A are present, they may be bridged. The metallocene compound may be filll-sandwich compounds having two or more ligands L which may be cyclopent~-iienyl ligands or cyclopent~ ne derived ligands or half-sandwich co.llpol~..ds having one ligand L, which is a cyclopent~ nyl ligand or ~;y~lop~ ienyl derived ligand. The transition metal atom may be a Group 4, 5 or 20 6 tr~n~ition metal and/or a metal from the l~nth~nide and actinirle series.
Zirconi-1m tit~ni~-m, and h~fnil-m are often ,oreft;--~d. Other ligands may be bonded to the tr~n~itior- metal, such as a leaving group, such as but not limited to hydrocarbyl, hydrogen or any other univalent anionic ligand.

~th~ls for making and using metallocenes are very well known in the art.
For ~ ~)!e, metallocenes are ~iisc~setl in United States Patent Nos. 4,530,914;
4,542,199; 4,769,910; 4,808,561; 4,871,705; 4,933,403; 4,937,299; 5,017,714;
5,026,798; 5,057,475; 5,120,867; 5,278,119; 5,304,614; 5,324,800; 5,350,723;
and 5,391,790 each fully incorporated herein by fe~lence.

W O 97/32906 PCTnUS97/03486 Further, the metallocene catalyst component of the invention can be a monocyclopent~iPnyl heteroatom co~ o compound. This heteroatom is activated by either an ~IIImoY~n~ an ionizing acli~,alor, a Lewis acid or a co~ A~i~?n thereofto form an active polyll~cli~alion catalyst system. These types 5 of catalyst ~y~lems are described in, for example, PCT International Publication WO 92/00333, WO 94/07928, and WO 91/ 04257, WO 94/03506, U.S. Patent Nos. 5,057,475, 5,096,867, 5,055,438, 5,227,440 and 5,264,405 and EP-A-0 420 436, all of which are fully ;ncol,~,ol~Led herein by ler~rence. In ~d~ition~ themetallocene catalysts usefiul in this invention can include non-cyclop~ont~li,onyl 10 catalyst components, or ancillary ligands such as boroles or carbollides in cc,n~bi.,aLion with a transition metal.

In one emborlim~nt the metallocene catalyst component is represented by the general formula (Cp)mMeRnR'p wherein at least one Cp is an unsubstituted or,15 plt;r~bly, a substituted cyclopPnt~içnyl ring; Me is a Group 4, 5 or 6 tr~n~ition metal; R and R' are intlepçntlçntly selectecl halogen, hydrocarbyl group, or hydrocarboxyl groups having 1-20 carbon atoms or conll)i~lalions thereof; m=1-3,n=0-3, p=0-3, and the sum of m+n+p equals the o~ tion state of Me.

In ~olhel embodiment the metallocene catalyst colllpol1elll is r~ ;sellled by the formulas:
(C5R'm)pR~ s(C5R~m)MeQ3 p x and R"s(csR'm)2~eQ
wherein Me is a Group 4, 5, 6 tr~n~ition metal, at least one CsR'm is a sllhstit~lted ~;yclop~ irnyl~ each R', which can be the same or di~iellL is hydrogen, alkyl, alkenyl, aryl, alkylaryl or arylalkyl radical having from 1 to 20 carbon atoms or two carbon atoms joined tog~.th~r to form a part of a substit~tec~ or unsubstituted ring or rings having 4 to 20 carbon atoms, R" is one or more of or a co...b;~.~l;on of a carbon, a ~ m, a silicon, a phosphorous or a nitrogen atom cQ~ g 30 rsdical bridging two (CsR'm) rings, or bridging one (CsR'm) ring back to Me, W O 97/329~6 PCTAUS97/03486 when p = O and x = 1 otherwise "x" is always equal to 0, each Q which can be thesame a,r d;rrele.l~ ;s an aryl, alkyl, alkenyl, alkylaryl, or arylalkyl radical having from 1 to 20 carbon atoms, halogen, or alkoxides, Q' is an alkylidene radical having firom 1-20 carbon atoms, s is 0 or 1 and when s is 0, m is S and p is 0, 1 or 2 and when s 5 is 1,mis4andpis 1.

PlGrtilably, the metallocene is leples_,.Led by the formula:

i( R )4 R3~ (CR8R9)m R~ ~CR8R )n ~(R10 )4 10 v~ elei~l M is a metal of Group 4, 5, or 6 of the Periodic Table preferably, zircon: lm, h~ m and l;L~ni.~ , most p.ere-ably zirconium;

Rl and R2 are identi~l or dirre.el.L, are one of a hydrogen atom, a C I -C 10 alkyl group, p~,f~;.~ly a Cl-C3 alkyl group, a Cl-Clo alkoxy group, pr~;r~;;-ably a 15 Cl-C3 alkoxy group, a C6-Clo aryl group, preferably a C6-Cg aryl group, a C6-Clo aryloxy group, plt;rt;.~ly a C6-Cg aryloxy group, a C2-Clo alkenyl group, pl~ .L~bl~/ a C2-C4 alkenyl group, a C7-C40 arylalkyl group, plc;rtlably a C7-CIo arylallkyl group, a C7-C40 alkylaryl group, preferably a C7-C 12 alkylaryl group, a Cg-C40 arylalkenyl group, ple~.ably a Cg-C12 arylalkenyl group, or a halogen 20 atom, pre:r~.ably chlorine;

W O 97/32906 PCT~US97/03486 R3 and R4 are hydrogen atoms;

R5 and R6 are identical or di~el e-,L, preferably i~lentie~l are one of a S halogen atom, pre~l~bly a fluorine, chlorine or bromine atom, a Cl-Clo allyl group, plerelably a Cl-C4 alkyl group, which may be halog~n~tetl a C6-Clo aryl group, which may be h~log~n~tet~, p~eI~-ably a C6-Cg aryl group, a C2-Clo alkenyl group, pl~rt;lably a C2-C4 alkenyl group, a C7-C40 -arylalkyl group, preferably a C7-Clo arylalkyl group, a C7-C40 alkylaryl group, preferably a C7-C12 al~yl&lyl group, a Cg-C40 arylalkenyl group, preferably a Cg-C12 arylalkenylgroup, a-NR215, -SR15, -OR15, -OSiR315 or-PR215 radical, whereinR15 is one of a halogen atom, preferably a chlorine atom, a Cl-Clo alkyl group, p..,f~,.al)ly a C l-C3 alkyl group, or a C6-C 10 aryl group, preferably a C6-Cg aryl group;
R7 is M2 ' M2 M2 ' M2 (C R213) --O--M2 o-- . C-- ' ~ M2 -B(Rl 1)-, -Al(Rl 1), -Ge-, -Sn-, -O-, -S-, -S0-, -SO2-, -N(Rl 1), -C0-, p~Rl 1), or -P~O)(Rl 1);
Wlle,. ~
20 Rll, R12 and R13 are itlçntic~l or di~ele .L and are a hydrogen atom, a halogen atom, a Cl-C20 alkyl group, preferably a Cl-Clo allyl group, a Cl-C20 W O 97/32~06 PCTrUS97/03486 fluoroalkyl group, ~l~re.~ly a Cl-Clo fluoroalky1 group, a C6-C30 aryl group, preferalbly a C6-C20 aryl group, a C6-C30 fluoroaryl group, p.~re.~bly a C6-C20 fluoroaryl group, a Cl-C20 alkoxy group, pl..rcl~bly a Cl-Clo alkoxy group, a C2-C20 alkenyl group, ~rere-~ly a C2-Clo alkenyl group, a C7-C40 arylalkyl 5 group, ~,~fc~ably a C7-C20 arylalkyl group, a Cg-C40 arylalkenyl group, ~r~fel,1bly a Cg-C22 arylallcenyl group, a C7-C40 allcylaryl group, plerti.~bly a C7-C20 al.kylaryl group or Rl 1 and R12, or Rl 1 and R13, together with the atoms binding them, can form ring ~yslelns~

M2 is silicon, ge~.A~ m or tin, p~eft:-~ly silicon or ge-.. ~t~ m most ~r~;rel.~bly silicon;

R8 and R9 are id~nti-~l or d;frelenl and have the m~ninec stated for Rl 1;

m and n are i~i~ntic~l or difr~c~l and are zero, 1 or 2, p-cr~.al)ly zero or 1, m plus n being zero, 1 or 2, preferably zero or 1; and the radicals Rl~ are i~entic~l or diff~l-,nL and have the ~ A~ g,c stated for R11, ]R12 and R13. Two ~ cent R10 radicals can be joined together to form a 20 ring system, ~.crel~bly a ring system co~ e from about 4-6 carbon atoms.

Alkyl refers to straight or branched chain substitll~ntc Halogen (halog~ ed) is fluorine, chlorine, bromine or iodine atoms, preferably fluorine or chlorine.
I
Particularly ~lcrclled metallocenes are compounds ofthe structures:

CA 02243~19 1998-07-20 W O 97/32906 PCT~US97103486 ~O

R8R9~(R10)4 ~(R10)4 ~R2 ~ ) R12 ~ ~R2 (B) R11 R12C~R6 ~6 ~(R1 o)4 ~l--(R1 o)4 wl~
M1 is Zr or Hf, R1 and R2 are methyl or chlorine, and R5, R6 R8, R9,R10, R11 and R12 have the above-mentioned mP~nings s These chiral met~llocçnes may be used as a .,.c~ e for the p-t;,~ Lion of highly isotactic poly~-ol~ylene copolymers. It is also possible to use the pure R or S form. An optically active polymer can be ~l ~pa, ed with these pure ~L~.~oiso...c.ic forms. Plere- ~bly the meso form of the metallocene is removed to ensure the center (i.e., the metal atom) provides steleoregular pol~lnt~ aLion.
Separation of the stereoicQmp~rs can be ilCCQIllpli~hed by known literature tcc~ es For special products it is also possible to use rac/meso l-~Lult;S.

Generally, the meta}locenes are plel~alt;d by a multi-step process involving repe~te(l deplo~GllaLions/met~ tiQn~ ofthe aromatic ligands and introclllc,tiQn of the bridge and the central atom by their halogen derivatives. The following reaction scheme illustrates this generic approach: -H2RC + ButylLi ~-------> HRCLi X-(CR8R9)m-R7-(CR8R9)n-X
--------------------~

W O 97/32906 PCTrUS97103486 H2Rd +ButyLi ~~ > ED~.dLi HRC-(CR8R9)m-R7-(CR8R9)n-RdH 2 Butyl Li _ _ _ _ _ _ _>

LiRC-cCR8R9)m-R7-(CR8R9)n-RdLi MlC14 >
(R8R9C)m ,RC ~R8R9C)m--RC

- R7 M1~ Cl R1 Li 1 7 'M1~ R1 ~ ~Cl I , \CI
(R8F~9C )n Rd (R8R9C )n - Rd (R8R9C)rl,--RC
R21 i 1 ~ ~R2 R8R9C)n Rd ~ /~
X = Cl, Br, I or O-tosyl; H2RC ~ R3 ~rlAition:ll methods for preyalill~. metallocenes are fully described in the Journal of O~ ~u1ol~ llic Chem., volume 288, (1985), pages 63-67, and in EP-A-32076:7, for ~ ion ofthe metallocenes desclil,cd, both of which are herein fully incolyol~ed by lerel~nce.

Illustrative but non-limiting eA~ll~les of these metallocenes include:
Din~Lll~l:,ilandiylbis (2-methyl-4-phenyl-1-indenyl)ZrC12 DillleLLylsilandiyll,;i~(2-methyl-4,5-b~n7oinrlenyl)ZrCI2;
D;ll~ ,;landiylbis(2-methyl-4,6-diisoprc,pylilldenyl)ZrC12;

W O 97/32906 PCT~US97/03486 DilllelLylsilall(liylbis(2-ethyl-4-phenyl-l-indenyl)zrcl2;
Dhll~lllylsilandiylbis (2-ethyl-4-na,~hlllyl-1-indenyl)ZrC12, Phenyl(Methyl)silandiylbis(2-methyl-4-phenyl- 1 -indenyl)ZrC12, Di,ll~.llylsilandiylbis(2-methyl-4-( 1 -naphthyl)- 1 -indenyl)ZrC12, S Dimethylsil~ldiylbis(2-methyl-4-(2-naphthyl)- 1 -indenyl)ZrC12, DimethylsilanJiylbis(2-methyl-indenyl)ZrC12, Dhlwlhyl~ diylbis(2-methyl-4~ 5-diisoproyyl- 1 -indenyl)ZrC12, Dimethylsilandiylbis(2,4,6-1- hllell~l- 1 -indenyl)ZrC12, Phenyl(Methyl)silandiylbis(2-methyl-4,6-diisopropyl- 1 -indenyl)ZrC12, 1~2-Fth~ntiiylbis(2-methyl-4~6-diisoplo~)yl-l-indenyl)ZrCl2, 1,2-R~ i;yl~ (2-methyl-4~6-diisopropyl-l-indenyl)zrcl2 Dh~ l,ylsilandiylbis(2-meehyl~-ethyl-1-indenyl)ZrC12, Dhllell,ylsilandiylbis(2-methyl-4-isoprol-yl- 1 -indenyl)ZrC12, Di.~ Lylsilandiylbis(2-methyl4-t-butyl- 1-indenyl)ZrC12, Phenyl(Methyl)silandiylbis(2-methyl-4-iso~ropyl- 1 -indenyl)ZrC12, Dinlelllyl~ diylbis(2-ethyl-4-methyl-l-indenyl)zrcl2 Dhnell-ylsilandiylbis(2,4-dimethyl- 1 -indenyl)ZrC12, Dimethylsilandiylbis(2-methyl-4-ethyl- 1 -indenyl)ZrC12, Di~ ;lhyl~ilandiylbis(2-methyl-a-~cçn~phth-1-indenyl)ZrC12, Phenyl(Methyl)silandiylbis(2-methyl~5-benzo-l-indenyl)zrcl2~
Phenyl(Methyl)silandiylbis(2-methyl-4,5-(methylbenzo)-1-indenyl~ZrC12, Phenyl(Methyl)silandiyll,is(2-methyl-4, S-(tt;l- ~ell~lbenzo)- 1 -indenyl)ZrC12,Phenyl(Methyl)silandiylbis (2-methyl-a-~cen~rhth-1-indenyl)ZrC12, 1,2-F~t.~ iirll is(2-methyl-4,5-benzo-1-indenyl)ZrC12 1~2-R~ ;ylbis(2-methyl-4~s-benzo-l-indenyl)zrcl2~
D~ ylsilandiylbis(2-methyl-4,5-benzo-1-indenyl)ZrC12, 1,2-Fth~n~iiylbis(2~4~7-trimethyl- 1 -indenyl)ZrC12, Dimethylsilal diyll,is(2-methyl- 1 -indenyl)ZrC12, 1 ,2-F I~ ] iylbis(2-methyl- l -indenyl)ZrC12~
Phenyl(Methyl)silandiylbis(2-methyl-1-indenyl)ZrC12, W O 97/3291D6 PCTnUS97/03486 Diphe:nylsilall.liylbis(2-methyl-1-indenyl)ZrC12, 1~2-Rnl~lul;yll~L(2-methyl-l-indenyl)zrcl2~
Di~ ,Ll-ylsilandiylbis(2-ethyl- 1 -indenyl)ZrC12, Dimethylsilandiylbis(2-methyl-5-isobutyl- 1 -indenyl)ZrC12, S Phenyl~Methyl)silandiylbis(2-methyl-5-isobutyl- 1 -indenyl)ZrC12, Di.~elllyls~ diylb;;~(2-methyl-s-t-butyl- 1 -indenyl)ZrC12, D;l~lc~hylsil~ldiylbis(2,5,6-ll ;lllelllyl- 1 -indenyl)zrcl2~ and the like These l~lcfe"~d metallocene catalyst components are described in detail in lO U S Patent Nos 5,145,819; 5,243,001; 5,239,022; 5,329,033; 5,296,434;
5,276,208; and 5,374,752; and EP 549 900 and 576 970 all of which are herein fully inc~ ed by ,efe.ence Any alkyl~h~m--Y~ne may be used as an activator for the metallocene 15 Generally alkyl~ Ps contain about S to 40 ofthe repealing units:

--R~ Al O ~x~lR2 ~or linear species and ~ ~ for cyclic species where R is a C1-Cg alkyl inclllAinp mixed alkyls Particularly ~ d _re the compounds in which R is methyl ~hlmc Y~n~ solutions, particularly 30 ,nelLylAl- .oY~~-e solutions which are p,t:~"ed, may be obtained from commercial W O 97132906 PCT~US97/03486 vendors as solutions having various concentrations. There are a variety of methods for ple~ g ~ mnY~ne~ non-limiting examples of which are described in U.S.
PatentNo. 4,665,208, 4,952,540, 5,091,352, 5,206,199, 5,204,419, 4,874,734, 4,924,018, 4,908,463, 4,968,827, 5,308,815, 5,329,032, 5,248,801, 5,235,081, 5,157,137, S,103,031 andEP-A-0 561 476, EP-B1-0 279 586, ~P-A-0 594-218 and WO 94/10180, each fully inco-~,.aLed herein by lerele.-ce.

Some MAO sol~ltions tend to become cloudy and ~ tin~lls over time. It may be adv~nt~eoll~ to clarify such solutions prior to use. A number of methods are used to create gel-free MAO solutions or to remove gels from the solutions.
Gelled solutions are often simply filtered or deç~nted to separate the gels from the clear MAO. U. S. Patent No. 5,157,137 discloses a process for Çul lllil~g clear, gel-free solutions of alky~ u~n~e by ll~a~ , a solution of alkylalul.lu,~le with an al~yd-ù.ls salt and/or hydride of an alkali or slllcs~line earth metal.
The metallocene, alkyl~ ..o~ e and support material may be combi.led in any manner or order. Examples of suitable support techniques are described in U.S. Patent Nos. 4,808,561 and 4,701,432 (each fully incorporated herein by ncc). Preferab}y, however, the m~.t~lloc~ne and alkyl~ o~ are 20 co...l-il-ed first and their reaction product combined with the support material.
Suitable .~ rles ofthis techn;1~1e are described in U. S. Patent No. 5,240,894and WO 94/28034, WO 96/00243, and WO 96/00245 (each fully inc~ ed herein by reference).

2~ rc.al)ly, a porûus support such as silica is used and the volume of metallocene and activator colll~hled with the support is less than about 4.0 times the total pore volume of the support, more preferably less than about 3.0 times the tûtal pore volume ofthe support, even more preferably less than about 2.5 times the total pore volume of the support.

W O 97132906 PCT~US97/03486 The procedure for measuring the total pore volume of a porous support is well ~lo ,vn in the art. Details of one of these procedures are rli~c~ssed in Volume 1, l~cp~""~ lal Methods in Catalytic Research (Ac~dçmic Press, 1968) - (sperific~lly see pages 67-96). This ~-~;rcl~ed procedure involves the use of a S r.l~r;c~l BET appal~ s for nitrogen absolplion. Another method well know in the art is des-;-il)ed in Innes, Totalporosity and Particle Density of Fluid Catalysts By Liquid Ti~ration, Vol. 28, No. 3, Analytical Che ~ L"I 332-334 (March, 1956).

When the volume of soll~tion col--l,incd with porous support material is less 10 than one times the total pore volume of the support, the support appears completely dry and free-flowing and is corl~equently easy to mix and ll~n~rei.
When volumes above one times the total pore volume of the porous support are used, the support becol-~s proglessively more difficult to mix and transfier as volum.e i~ ases because it has the cor~ t~ncy of damp or wet mud. At greater 15 volum.es of solution, a slurry is eventually formed such that one can observes_p~liol1 ofthe sollltion and support as the silica settles. At the slurry stage, the support is easier to mix and handle. These factors should be considered when choosing solution volumes.

l~egardless of the amount of solution used, it is preferable to combine the suppa,rt and sohltioll such that the solution is evenly distributed among the support icles. Thus it is plcrcl~ble to add the so~ntis: n to the support slowly either as a spray or drop-wise while the SU~lpOI ~ iS mixed.

If the catalyst system is supported, it is preferably dried at least to a free flowing powder prior to storage. Heat and/or vacuum may be used to dry the catalyst. Typically, te.~ re in the range of from about 25~C to about 1 00~C is used :For a time period ranging from about 4 to about 36 hours. It may be adv~nt~geol-~ to dry the catalyst without vacuum or with a flow of warm inert gas such as nitrogen.

W O 97t32906 PCT~US97/03486 After drying, the final weight ratio ofthe ~ mimlm ofthe alkylalu~ e to the metal of the metallocene as determined by f~l~m~nt~i analysis is preferably in the range of from about 15 to about 170, more preferably from about 50 to about 150, even more preferably from about 80 to about 125.

The catalyst sy~lGllls of this invention may be used directly in poly--,~,.i~Lion after storage or the catalyst system may be prepolyrnerized before or after storage us;ng methods well known in the art. For details r eg~ ~lillg prepolyll.e~i~dLion, see United States Patent Nos. 4,923,833 and 4,921,825, EP 0279 863 and EP 0 354 893 each of which is fully incol~,o-~ed herein by rl_rGlGnce.
The catalyst ~:ile-ns of this invention may also be corllbilled before or a~er storage with one or more additives such as scavengers. F.x~ ,les of suitable sca~,ngil~gcompounds include triethyl~ min--m (TEAL), llilllGlllyl~ min~m (TMAL), tri-isobutyl~lllmin.lm (TIBAL), tri-n-hexyl~hlminl~im (TNHAL) and the like.

After storage, the catalyst system of this invention may be used in ~he poly...~ ion of any mo.-olnGl and optionally comonomers in any process in~lu-~in~ gas, slurry or solution phase or high pressure autoclave procçsses (As 20 used herein, unless di~G-e~ ted "polylll~li,d~ion" incl~ldes copoly-nt;li~dlion and "monomer" in~l~lc~es co.-~on~-llel-.) Preferably, a gas or slurry phase process is used, most pl~,fe~ ly a bulk liquid propylene polylll~ alion process is used.

In the ~ ,rG--~d embodiment, this invention is di.ec~ed toward the bulk 25 liquid poly~ alion and copolyll,elizalion of propylene or ethylene, particularly propylene, in a slurry or gas phase pol~ on process, particularly a slurry polyl,le~ ion process. Another embodiment involves copol~lllt;li,dlion reaction~of propylene or ethylene, particularly propylene, with one or more of the alpha-olefin ~--~ G~ having from 4 to 20 carbon atoms, ~r._rc.~bly 4-12 carbon atoms, 30 for ~ ,le alpha-olefin comonomers of ethylene, butene- 1, pentene- 1, 4-W O 97/32906 PCTrUS97/03486 1~
meth~ nl~..P,-I, hexene-l, octene-l, decene-1, and olefins such as styrene, cyclopP!nJ~ns or norbornene. Other suitable mt)nom~rs include vinyl, diolefin~ such as die~nes, for~ pl~, 1,3-but~ n~, 1,4-h~oy~ enp~ norborn~ n~or oll,ulllel~e~ acetylene, ethylidene norbornene and aldehyde monomers.

Typically in a gas phase polyl.lcliLa~iol~ process a contim~Qll~ cycle is employed where in one part of the cycle of a reactor, a cycling gas stream, el~;se kno~,vn as a recycle stream or fllli-~i7ing ..-~-1;,.... is heated in the reactor by th,e heat of polyn~eliLaLion. The recycle stream usually conLain~ one or more10 . . .nl-o. . .e, j continuously cycled through a fll~idi7ed bed in the ~I ~sence of a catalyst under reactive contlitinn~ This heat is removed in another part of the cycle by a cooling system ~ ..,al to the reactor. The recycle stream is withdrawn from the fll.i~li7~(1 bed and lecycled back into the reactor. Simllh~neously, polymer product is w;~hdlawll from the reactor and new or fresh monomer is added to replace the poly-~ 1 mo~ r. (See i~or ~ --plc U.S. Patent Nos. 4,543,399; 4,588,790;
5,02~3,670; 5,352,749; S,405,922, and 5,436,304 all of which are fully incorporated herein by lcrclcllce.) A slurry polyll.e.iL~Iion process generally uses pressures in the range of 20 about 1 to about 500 i,l ...n~l.h~. es or even greater and temperatures in the range of -60~l" to about 280~C. In a slurry polyllle.i,alion, a suspension of solid, particulate polymer is formed in a liquid polylllcliza~ion medillm to which ethylene and CQ~ O~ j and often hydrogen along with catalyst are added. The liquid emp]ioyed in the polyllleliL~ion merlillm can be, for example, an alkane or a 25 cyclo~ ne. The .~c~ ernployed should be liquid under the conditions o poly...~ ;onandrelativelyinert. Non-limitingeY~mplesofliquidmer~ m~
inch.~lde hexane and i~ob~t~n~.

W O 97/32906 PCTrUS97/03486 Plerel~bly the catalyst system after storage has a productivity of at ieast about 2000 g polymer~g catalyst, pl~;relably at least about 2500 g polymer/g catalyst, most prerel~ly at least about 3000 g polymer/g catalyst.

Ex~l?les In order to provide a better underst~nding of the present invention in~ tling repl~senl~Li~e advantages thereof, the following eY~mples are offered.

Catslyst Preparations F~D ~IC 1 In an inert N2 glove box 0.50 g of dimethyl~ n~liyl-bis(2-methyl-4-phenyl-indenyl) ~le~)~h~llll dichloride and 18.50 g of 30 wt% DMA0-25010 sol~ltir~n in toluene (Albemarle Corporation, Baton Rouge, LA) were colnbilled under stirring. Al/Zr molar ratio in the solution was 110. The resulting deep red precursor was added slowly while stirring to 10.0 g of MS948 silica (Davison Ch~mi~ ~I Division of W. R. Grace, Raltimore, MD~ previously dehydrated to 600~
C in a stream of flowing N2. The mud was dried at 28-29 inches of mercury vacuum until 15.56 g offree flowing, finely divided solid was ol~ .ed. Testing showed that the amount of volatiles in the solid was reduced to 1.1% by weight.
F1P..". ..~I analysis showed 15.41% Al and 0.55% Zr.

25 FY~mrle 2 ~ an inert N2 glove box û.379 g of dimethy~ ne(liyl-bis(2-methyl-4 phenyl-indenyl) ;~,~o~ lll dichloride and 14.10 g of 30 wt% DMA0-25010 sf~l~tio~ in toluene (Albemarle Colyo~ on~ Baton Rouge, LA) were combined 30 under stirring. Al/Zr molar ratio in the solution was 110. The resl-lting deep red W O 97t32~0~ PCT~US97/03486 ~q precursor was added slowly while stirring to 10.0 g of MS948 silica (Davison ~hPn~ Division of W. R. Grace, R~ltimnre~ MD) previously dellydl ~led to 600~
C in a stream of flowing N2. The mud was dried at 28-29 inches of Ille.~uly vacuum until 15.56 g of free flowing, finely divided solid was obtained. F.lf~m~nts S analysis showed 16.55% Al and 0.29% Zr.

Comparative E~ample 3 In an inert N2 glove box 0.25 g of dimethyleil~ne~liyl-bis(2-methyl-4-phenyl-indenyl) zirconium dichloride and 18.53 g of 30 wt% DMAO-25010 sol~ltion in toluene (Albemarle Co.yo~lion~ Baton Rouge, LA) were co...l~;ned under stin inp Al/Zr molar ratio in the soilltiot~ was 217. The res~llting deep red ,u~ r was added slowly while stirring to 10.0 g of MS948 silica (Davison ChP.mir~l Division of W. R. Grace, R~ltim~re, Mr)) previously dehydrated to 600~C in a stream of flowing N2. The mud was dried at 28-29 inches of ~II~ .iUly vacuum until 15.61 g free flowing, finely divided solid was oblained. Testing sllu~ed that the amount of volatiles in the solid was reduced to 0.7% by weight.F.~ l analysis showed 15.77% Al and 0.19% Zr.

E~ample 4 In an inert N2 glove box 0.26 g of dilllt;Llly~ ne(~iyl-bis(2-methyl-indenyl) ~h~ ~ m dichloride and 13.25 g of 30 wt% MAO solution in toluene (Albemarle Co.~o.~liûn, Baton Rouge, LA) were co-.-l~; ec~ under stirring and 5.60 g of toluene added. Al/Zr molar ratio in the solntion was 126. The resl~lting deep red .-,cu~or was added slowly while stirring to 10.0 g of MS948 silica (Davison Ch~nlic~l Division of W. R. Grace, R~ltimore~ MD) previously dehydrated to 600~
C in n stream of flowing N2. The mud was dried at 28-29 inches of mercury vacuum until 14.94 g free flowing, finely divided solid was obtained. Fl.o.men~lanalysis showed 16.49% Al and 0.45% Zr.

W O 97/32906 PCT~US97/03486 ~P

Comparative ~ample 5 In an inert N2 &~ osl~k - ~, 850 g of di--lelllyl~ ne~iyl-bis(2-methyl-indenyl) S ~.ion~ - dichloride was cG-Ilbh~ed with 15 gallons toluene and 165 Ibs of 30 wt%
methyl~ A ~e so'-ltin~ in toluene (Albemarle Corporation, Baton Rouge, LA) was added to form the precursor having an Al to Zr ratio of 210. Separately 150 Ibs of MS948 silica (Davison Chemical Division of W. R. Grace, R~ltimore, MD) previously dehydrated to 600~C in a stream of flowing N2 was added to a 200 gallon reactor. The precursor was added to the silica while stirring. Then 28-29inches of l~ u-y vacuum was applied to the reactor while the reactor jacket was heated to 160-165~F. After 7.5 hours the catalyst was collected as a ~ee flowingpowder. Testing showed that the amount of volatiles in the solid was reduced to 3.35% by weight. Fl~m~nt~l analysis showed 9.28% Al and 0.17% Zr.
~5 Cntalyst Stability EVPI - nn An oven filled with N2 and IL~ s~ ed at 100~F (34~C) was used to heat s~ Pss steel cylinders of catalyst for the stability study. The cylinders were 20 ch~,ed with catalyst inside a N2 purged glove box. Before sealing the cylinder 15 psi of N2 ~,less,lre was applied to prevent c~ ;on ofthe catalyst during cylinder h~n~llin~ in air. At preset times a cylinder was removed from the oven,sf~ d to the glove box and the co..le~ mple(l The cylinder was returned to the oven and heating continllec~ The aged catalyst s~mrles were tested for 25 poly-l.el~lion activity as described below.

W O 97~2906 PCTrUS97/03486 Cat~llyst Polymerization Evaluation A 2 liter autoclave reactor previously flushed with N2 and CQI~ g J triethyl~ mim-m (0.25 mL of a 1 M solution in hexane) and 1000 mL of propylene S was hleated to a ~e.ll~tl~lu~e o~' 70~C. A 75 mg sample of the catalyst sample pl~palcd and aged as sbove was slurried in 2 mL of hexane and cl~,cd with 250 mL of propylene to start the re~ctinn A~fter one hour the reactor was cooled, vented, purged with Nz for 20 ...;..~ s and then opened. The granular pol~ .ylene was h~ rGl-ed to a ceramic dish and allowed to dry in a fume hood 10 ovt~ L~. The next day the poiymer was ~urther dried in vacuo at 75~C for one hour. The final dried polymer was weighed.

rD~ tion rr Table I Sl-,.-.--~u~S stability of catalyst activity after aging at 100~F (34~C).

Table 1 Catalyst Productivity after heat aging for hours shown(b~
F.~j~.. pl~ Zr(~) 0 40 85 157 250 325 110 3144 nd(~) nd 3115 3056 3105 Col~np. 3 217 2680 1895 1811 1672 1736 1540 (a3 Precursor molar ratio.
20 (b) Gr~ m~ PP per g catslyst heat ag~d at 100~F (34~C) for time shown.
(c) not ~

The data show that the catalyst of l:;x~mrle 1 having a lower .AIIlmim~m to Zilcal~-u.ll molar ratio was stable to heat aging at 100~F (34~C~ while the catalyst W O 97/32906 PCTrUS97/03486 of Col.lp~ e ~.~mple 3 at three times the ratio lost 30% catalyst activity after 40 hours and about 45% after about 2 weeks.

The 100~F (34~C) heat aging study ofthe catalyst of Example 1 was contimled as S shown in Table 2.

Table 2 Days Productivity~
21.4 3017 28.4 2813 34.4 2704 42.3 2723 56.3 26g6 65.2 2873 90.2 2109 (a)~l~L~;ly~PPp~g~t~yst).
The lOOOF heat aging study of the catalyst of Example 2 is shown in Table 3.

Table 3 Days Productivity 5.8 2819 18.7 2443 32.6 2480 43.5 2528 53.4 2647 68.4 2419 (~)~.' ~i~y(gPPp~g~t~yst).

W O 97/32'306 PCTrUS97tO3486 ~ 3 The data show that except for a small loss in activity, the catalyst ~I-A;~IA;~
effective activity for more than two months at 100~F (34~C).
~, The results of auutl-er 100~F ~34~C) heat aging co-"~ison with a di met~llocPn~ are shown in Table 4.

Table 4 Days Example 3 Comp. FY~mrle4 3 _~n) 1788(b 7.7 3903 15.7 3863 22.6 3589 28.1 - 1197 33.8 3180 43.6 3647 53.5 3677 68.4 3373 (a)not-~ -~) ~ud~vity (g PP p~ g catalyst).

The catalyst of Example 4 having an Al/Zr molar ratio of 126 was more stable to activity loss than the catalyst of CGI--pa-~ e F.~mple 5. The latter 15 having an Al/Zr of 210 lost about 50% activity after heat aging for 2 months while the c.atalyst with the ratio of the instant invention ~ ed about 85% activity in about the same time period.

W O 97/32906 PCT~US97/03486 While the present invention has been described and illustrated by .,rt;-e.lce to particular embo~ it will be appreciated by those of ol .lin&~y skill in the art that the invention lends itself to many dirrerenl variations not 5 illustrated herein. For these reasons, then, reference should be made solely to the appended claims for purposes of determining the true scope of the present invention.

~Ithol~h the a~pend~.L claims have single appendpnciçs in accordance 10 with U.S. patent practice, each of the features in any of the appendant claims can be col~i"ed with each of the features of other appendant claims or the main claim.

Claims (15)

Claims

1. A method for polymerizing olefins comprising contacting one or more olefins under suitable polymerization conditions with an active metallocene catalyst system comprising metallocene and an alkylalumoxane wherein the ratio of the aluminum of the alkylalumoxane to the transition metal of the metallocene used to prepare the catalyst system is in the range of from 85:1 to 150:1 and wherein the active catalyst system has been stored at a temperature in the range of from 20°C to 45°C
for at least two days.

2. The method of claim 1 wherein the time period is at least 14 days.

3. The method of claim 1 wherein the time period is at least 35 days.

4. The method of claim 1 wherein the time period is at least 56 days.

5. The method of any of the preceding claims wherein the catalyst system furthercomprises a support material.

6. The method of claim 4 wherein the catalyst system productivity is at least 75%
of its original productivity before storage.

7. A method for preparing a metallocene catalyst system, comprising the steps of:

(a) combining a metallocene catalyst component with an alkylalumoxane wherein the ratio of the aluminum of the alkyl alumoxane to the transition metal of the metallocene is in the range of from 80:1 to 200:1 said combination excluding a stabilizing olefin having the general formula R1R2R3CCH=CH where R1, R2, and R3 are alkyl groups with carbon numbers ranging from 1-20; and (b) storing the combination at a temperature in the range of from 20°C to45°C for a time period of at least two days.

8. The method of claim 7 wherein the time period is at least 7 days.

9. The method of claim 7 wherein the time period is at least 21 days.

10. The method of claim 7 wherein the time period is at least 49 days.

11. The method of claim 7 wherein the time period is at least 56 days.

12. The method of claims 7 - 11 wherein the ratio of the aluminum of the alkyl alumoxane to the transition metal of the metallocene is in the range of from 90:1 to 125:1.

13. The method of claims 7 - 12 further comprising the step of combining the metallocene and alkylalumoxane with support material.

14. The method of claims 7 - 13 wherein the support material is a porous inorganic oxide and the metallocene and alkylalumoxane are combined first and their reaction product combined with the porous support.

15. A metallocene catalyst system prepared by the method of claim 7.