Note: Descriptions are shown in the official language in which they were submitted.
~IL29~
POLYMERIZATION CATAL~ST AND METHOD
Bac~ground o the Invention
_
The catalyst of this invention is suitable for the
polymerization and copolymerization of ethylene and other 1-
olefins, particularly of 2-8 carbon atoms and the copolymerization
of these with l-olefins of 2-20 carbon atoms, such as propylene,
butene and hexene, for example. It is well suited for economical
particle form ana gas phase polymerization processes. The active
component of the catalyst is supported upon particles of an
10 organic polymer, the selection of which affects the particle
size, melt index and molecular we~ht distributlon of the product
polymer Further~ product bulk density is relatively high and is
controllable by selection of the polymeric carrier.
Summary of the Invention
. . .
An improved catalyst for the polymerization and co-
polymerization of olefins is prepared by combining three reactive
materials in the presence of particles of an or~anic polymeric
carrier. A reac-tion product of the three reactive materials is
9~
formed on and adheres to the carrier and is activated by contact
with an effective quantity of an alkyl alumin~n compound such as
trialkyl aluminum, for example.
The support reaction product is believed tv be a
complex of the three reactive materials, and incorporates a major
portion of the titaniumin~ highly active form over a wide range
of mole ratios of the reactants. Due to the inherent high
reactivity of the complex, it is not necessary to remove non-
reactive titanium from the catalyst, but washing of the catalyst
may be conducted, i~ desired.
The catalyst is, because of its high activity, well
suited for use in the particle form polymerization process in
which the suppoxted catalyst, the co-catalyst, and olefin monomer
are contacted in a suitable solvent or in a gas phase process in
which no solvent is necessary.
The three reactive materials may be added to the carrier
in any order and comprise (1) an alkyl aluminum halide, (2) a
dialkyl magnesium compound or a complex of dialkyl magnesium and
alkyl aluminum compounds, and (3) a titanium alkoxide or titanium
alkoxide halide.
The alkyl alwminum halide is chosen from the group
comprising dialkyl aluminum halides, alkyl alumi~um sesquihalides,
and alkyl aluminum dihalides, with ethyl aluminum sesquichloride
being preferred. The titanium compound is of the formula
Ti (OR)nX4_n where R is an alkyl group, X is a halogen atom, and
n is an integer between 1 and 4, inclusive. A preferred titani~
compound is titanium tetraisopropoxide.
Preferred dialkyl magnesium compounds are dibutyl
magnesium, di-n-hexyl magnesium and butyl ethyl magnesium, any
of which may be complexed with an alXyl alumin~m comp~und, such
--2--
.. . .. ..... . . ... , . , ~ ., .. .. .. , .. . ,, .... . ... . . .. .... . . .. .. . . .. .. _ . .... . ... . . .. ...
......
~Z98~
as a trial~yl alumlnum, to increase the solubility o~ the
magnesium compound and/or decrease -the viscosity of the mag-
nesium compound solution.
The invention as broadly claimed herein in one aspect
pertains to a supporte~ olefin polymerization c~talyst active
in the presence oE an alkyl aluminum co-catalyst prepared ~y
mixing reactive materials comprising an alkyl aluminum halide,
a dialkyl magnesium compound and a reducible titanium compound
of the formula Ti(OR)nX~ n where R is an alkyl group, X is a
halogen atom, and n is an integer between 1 and 4, inclusive,
in the presence of a particulate organic polymer to form a
reaction product supported on the particles. The particulate
organic polymer comprises a graft copolymer of about 70 - 99.95
weight percent of a polyolefin polymer and about 30 - 0.05
weight percent of at least one monomer selected from the group
consisting of polymerizable cyclic ethylenically unsaturated
carboxylic acids and carboxylic acid anhydrides. The reactive
materials are present in amounts to produce a ~uantity of the
reaction product which is less than about 30 percent of the
total weight of the reaction product and the organic polymer
particles, the supported reaction product being dried by heating
at an elevated temperature which is less than the softening
temperature of the organic polymer.
The invention also comprehends the method of making
polymers of one or more l~olefins which comprises polymerizing
the olefins under polymerizing conditions with the catalyst
as referred to above.
The invention also comprehends the method of preparing
a supported olefin polymerization catalyst active in the
presence of an alkyl aluminum co-catalyst comprising mixing
reactive materials as referred to above and regulating the
quantities of the alkyl aluminum halide, the dialkyl mag-
nesium compound and the tltanium compound such that the reaction
; product is less than about 30 pe~cent of the total weight of
3--
LZ~8~
~lle reaction product and the organic polymer particles,
the supported reactlon product being dried by heating at an el-
evated temperature which is less than the softening temperature
of the organic polymer.
Description of the Preferred Embodiments
____ _ _
Preparation of the Carrier
.
The reaction product catalyst of the invention forms
and adheres to the surface of polymeric carrier particles to a
degree dependent upon the physical and chemical nature of the
carrier material. Similarly, the charactcristics of the product
polymer which grows from the catalyst surface is determined by
the carrier characteristics.
In order for a particle form polymeriæation reaction
to proceed by polymer growth on the carrier, it is obviously
necessary that the carrier particles remain intact (i.e., not
melt, dissolve or otherwise degrade) under reaction conditionc~.
Particle form polymerization may be conducted at tcmpera-tures
up to 110C. in a hydrocarbon solvent such as isobutane, for
example. Therefore, a polymeric carrier which melts or other~ise
de~rades ~t temperatures up to 110C.,or which dissolves in iso-
butane or a similar solvent at these temperatures, is not a
suitable catalyst support.
Further, the carrier material must be substantially
chemically inert with respect to the catalyst formed thereon.
It has been found that a very hi~h concentration of polar yroups
in the carrier material results in reaction of the catalyst
forming reactants with the carrier and therefore should be avoided.
However, a relatively small amount of polar groups in the carrier
is useful in promoting adherence and uni~rm distribution of the
catalyst thereon. Such adherence may also be promotcd by b]cnding
~ - 3a ~
~2984~
up to about 20 percent of an amorphous or only slightly
crystalline hydrocarbon polymer into a predominarltly crystalline
polymeric carrier material.
It has been found that production of carrier particles
by grinding of carrier material results in a carrier surface
which promotes adherence of the catalyst to the carrier. The
technique known as cryogenic grinding is especially preferred.
The carrier particles may range in diameter from about 20
microns to about 5 millimeters.
For use in automatic catalyst feeding valves commonly
used in particle form polymeriæation plants, relatively small
particles are generally preferred, although al-ternate methods of
feeding can be employed for larger carrier particles. In
addition, normal feeding valves operate most effectively with
materials having flow characteristics similar to those of
commonly used silica catalysts. Approximately spherical carrier
particles are especially suitable for use in such automatic
valves. Furthermore, flow properties of the carrier are
improved by the addition of a small amount, such as up to about
10% by weight, of pyrogenic silica such as the silica having the
trade mark Cab-O-Sil, for example.
Specific examples of suitable carrier materials are
--4--
~Z984~L
high density polyethylene and :isotact:ic polypropylene. U.S.
patent 3,873,643 to Wu et al and assicJned to the assiynee
hereof, provides an excellent example of a polymer which
contains low concentrations of polar groups and which is
suitable for use as a carrier ln t-his invention. The material
of paten-t 3,873,643 comprises high densi-ty polyeth~lene grafted
with organic anhydrides.
More particularly, the polymers disclosed in Wu et al
3,873,643 are characterized as copolymers comprising polyolefins
which are modified by grafted cyclic and polycyclic unsaturated
acid or acid anhydride monomers, or both, which exhibit improved
compatability with other materials, and which are chemically
reactive.
By polyolefins, it is meant polymers and copolymers of
ethylene, propylene, butenes and other unsaturated aliphatic
hydrocarbons. Suitable polyolefins include ethylene
homopolymers prepared by low pressure methods (linear or high
density polyethylenes) and copolymers of ethylene with up to 40
weight percent of such higher olefins as propylene, l-butene and
l-hexene. The copolymers may contain up to 5~ of such di- or
triolefins which are used commercially in ethylene-propylene
~2984~
terpolymers such as ethylidene-norbornene, methylenenorbornene,
1,4-hexadiene and vinylnorbornene. Also, it is preferable
sometimes to graft to blends of two or more of the above
homopolymers 7 copolymers and terpolymers.
By cyclic and polycyclic unsaturated acids and anhy-
drides, it is meant compounds which conkain one or more car-
boxylic and/or heterocyclic moieties not including the
anhydride ring. The rings may be simple, -fused, bridged,
spiro, joined directly, joined through aliphatic chains
containing one or more carbon, oxygen or sulfur atoms, or
combinations of the above ring arrangements. These classes
are represented respectively by the following structures
which are meant to be illustrative rather than limiting:
~C~ o
" C
o o
simple fused
4-methyl cyclohex-4-ene 1,2,3,4,5,8,9,10-octahydro
1,2-dicarboxylic acid anhydride naphthalene-2,3-dicarboxylic
(4-MTHPA) acid anhydride
~C\' O
~C _ ~
bridged spiro
blcyclo[2.2.2]oct-5-ene- 2-oxa-1,3-diketospiro[4,4]non-
2,3-dicarboxylic acid anhydride 7-ene
(BODA)
, ~ ,
--6--
z~
~, c~
bridged brldged, mixtures of isomers
bicyclo[2.2.1]hept-5-ene-2,3- x-methyl bicyclo~2.2.1]hep~-5-
dicarboxylic acid anhydride ene-2,3-dicarboxylic acid
(NBDA) anhydride (XMNA)
e~ ~0 ~c~.O~c~ O~
C joined thru an aliphatic chain
o and heterocyclic
joined directly and aromatic 2-furoic acid
4-(2-cyclopentenyl)-benzer.e 1,2-
dicarboxylic ~cid ~nhydrlde
CooJ~ O
both fused and bridged rings
maleo-pimaric acid (M-PA)
Rings may contain 3 to 8 atoms but generally 5 and 6
membered rings are preferred. The monomer may contain
aromatic rings but at least one ring should be aliphatic.
The olefinic bond is preferably unconjugated with the acid
or anhydride groups. Such conjugated monomers as acrylic
acid, methacrylic acid, itaconic anhydride and fumaric acid
polymerize too fast for the successful practice of this
invention. If, however, the olefinic bond is conjugated but
otherwise deactivated as by alkyl substitution, the monomer
can be used in this application. A non-limiting example of
such a conjugated but deactivated monomer is cyclohex-l-ene,
2-dicarboxylic anhydride.
The copolymers consist of about 70-99.95 weight
percent of polyolefin and about 0.05-30 weight percent of the
cyclic unsaturated acid or acidanhydrid.e or mix-tures and these
resulting graft copolymers are capable of blending or reacting
,~j 7
~12~
with a wide variety of other materials to mod.ify the copolymer
further.
The polyolefin used in making the graft polymer
carrier material used ln this invention may comprise a
polyethylene homopolymer with a densi-ty of at least about
- 0.940 - 0.965 and may be essentia:Lly linear.
The polyolefin may also comprise a terpolymer such as
one of ethylene, propylene and up to about 5 weigh-t percent of a
cyclic or acyclic aliphatic diene or mixtures thereof.
Excellent monomers in the graft copolymer of this
invention include 4-rnethylcyclohex-4-ene-1,2-dicarboxyl}c aci.d
anhydride, tetrahydrophthalic anhydride, x-methylnorborn-5-ene-
2,3-dicarboxylic anhydride, norborn-5-ene-2,3-dicarboxylic
anhydride, 2-cyclopentenyl acetic acid, abietic acid, maleo-
pimaric acid and bicyclo[2.2.2~oct-5-ene-2,3-dicarboxylic
anhydride.
Methods of preparing graft copolymers such as
described above being a more detailed disclosure of the
substance of U.S. patent 3,873,643.
Catalyst Forming Re_ctants
The catalyst of the invention comprises the reaction
--8--
product of (1~ an alkyl aluminum halide, (2) a dial~yl magnesium
compound or complex, and (3) a titanium alkoxide or titanium
alkoxide halide, supported on an organic carrier as described
above and used in the presence of an alkyl ~luminum co-cat~lyst~
The reaction of the three components may be carried out at ~oom
temperature or below in the presence of carrier particles and is
conducted in a suitable solvent such as isobutarle, for
example.
~he alkyl aluminum halide is chosen fxom the group
comprising dialkyl aluminum halides, alkyl aluminllm sesquihalide~
and alkyl aluminum dihalides. A preferred alkyl aluminum halide
is ethyl aluminum sesquichloride.
The dialkyl magnesium compound, which may be in the
form of an alkyl aluminum complex, is preferably dibutyl magnesium,
di n-hexyl magnesium or butyl ethyl magnesiurn.
The titanium compound is an alkoxide or mixed alkoxide
halide of the formula Ti(OR)nY.4 n where R is an alkyl group of
1-6 carbon atoms, X is a halogen atom, and n is an integer between
1 and 4, inclusive. Titanium tetraisopropoxide is preferred.
Prior catalysts utili~ing aluminum chloride or another
chloride tend to be corrosive and require special handling
equipment. A washing step is also required to remove residual
chloride from the catalyst. In the practice of the present
invention, the alkyl aluminum halide and the titaniwn alkoxide
halide, if any, complex with the dialkyl magnesium compound to
substantially the fullest possible extent re~ardless of the
respective mole ratios of these components over a wide range
of ratios, thereby eliminating residue from the catalyst surface,
as well as effecting a reduction in los~ titanium and
magnesium. Hence, no special equipment is necessary for handlin~
the catalyst of the invention, nor is a washing step nec~ssary.
_g_
, ..... , . .. ,, .. . . .. . ... . ... . ~ . .. ., . . ...... ... . ~.. ..
The three reactive components may be in hydrocarbon
solution and, when reacted in the presence of a solvcnt and
polymeric carrier particles of tlle typc described, dcposit an
insoluble reaction product on -khe surface o the particlcs~ 1'he
mi~ing of the reactive materials is prefcrably dorle at vr bc]ow
room temperature. After the mixing is complete, the solvent is
evaporated, preferably by heatlny ahove room tcmperature but at
a temperature less than the softening temperature of the pol~meric
carrier. The evaporation step promotes the formation of particles,
as opposed to irregularly sized chunks, in a slurry polymerization
reaction utilizing the resulting catalyst, and decxeases reactor
fouling~
It is normally best to heat the catalyst under inert gas
at a temperature of about 90-100C. for from 1/2 to 10 hours, or
until free oE solvent.
The amount of the titanium componen-t is chosen to give
preferably about 0.1 to 10% by weight titanium in the reaction
product. The respective quantities of the titanium, magnesium
and aluminum halide compounds are preferably selec-t~d such that
the weight of the reaction product supported on the polymeric
carrier particles is less than about 306 of the total ~eight
of the particles and reaction produc-t. The respective mole ratios
of the alkyl aluminum halide, the dialkyl magnesium and the ti-L~nium
alkoxide may be adjusted to give optimum reactivity or to modify
polymer properties. Further, the mole ratio of the alkyl
aluminum co-catalyst to the solid catalyst may be adjusted and
hydrogen may be supplied to the polymerization reaction system
to control product molecular weight, as is well~known in the
art.
~eaction Conditions
The particle form reaction system is haracterized by thc
introduction of monomer to an agi-tated catalyst-solvent slurry.
--10--
. - .
~Z9~34~
Th~ solvent is typically isobutane and the reactio~ is best
carried out iII a closed vessel to f~cilitate pressure and
temperature regulation. Pressure may be regulated by the
addition of nitrogen and/or hydrogen to the vessel. Additiorl
of the latter is useful for regulation of the molecul~r weigi~t
of product polymer, as described in the following examples.
Particle form polymerization of ethylene with the
catalyst of this invention is best carried out at about 105C.
to llQC. at a pressure of between 35 and 40 atmospheres. In
gas phase polymeri2ation, the temperature may range from less
than about 85C. to about 100C. with a pressure as low as
about 20 atmospheres. Copolymers may be produc~d by either
process by addition of propylene, butene-l, hexene-l and similar
alpha-olefins to the reactor. Production of copolymers of
relatively low density is preferably carried out at a relatively
low temperature.
Example 1
Pellets of high density polyethylene with 1.33 weight
percent X-methylbicyclo~2.2.1]hept-5-ene-2,3-dicarboxylic acid
anhydride gra~ted to it, as described in U. S. Patent 3,873,643
and herein identified as XMNA graft, were ground to particles of
about 1 mm in diameter. 10 grams of ~ ~A particles was char~ed
to a flask from which air was removed by N2 purge. 20 ml each
of cyclohexane and a heptane solution of ethyl aluminum sesqui-
chloride (7.7 mmoles Et3A12C13) were added while stirrin~ vigc~rously.
10 ml of a heptane solution of a dlbutyl magnesium/
triethyl aluminum complex (9.1 mmole magnesium and 1.5 mmole
triethyl aluminum) were quickly introduced to a flas~ while
stirring. 2.0 ml (6.64 mmoles) of pure titanium tetraisopropoxide
was added to the resultin~ slurry, and the color of the mixture
~'
~2~
became very dark. The solvent was cvaporated and th~ catalyst ~as
heat-aged by heatincJ at 90C. for 30 minutes under the N2 purge.
The remaining solid material was then tested as a suppor~ed ethy1ene
polymerization catalyst.
In a first polymerization tes-t, 0 2230 g of the solid
material was charged, under N2, to a closed polyrnerization vessel.
500 ml isobutane was forced into the vessel and e-thylene was
added to maintain the total pressure at 550 psig~ The vessel
was maintained at lOS~C. throughout the reaction. In 25 minutes,
6 grams of polyethylene was produced for an hourly reactivity
with respect to the solid catalyst of 65 g/g.
In a second polymerization test, the procedure was
identical except that 0.0958 g of the catalyst and 0.3 Inl (0.28
mmole) of triiso~utyl al~inum (TIBAI,) solution were charged to
the polymerization vessel. In this case, the reactivity was 910
g/g/hr with respect to the solid catalyst, 580 g/g/hr with
respect to the total catalyst weight including the triisobutyl
aluminum, and 134,000 g/g/hr with respect to titanium, clearly
showing the beneficial effect of using a triiso~utyl aluminum co-
catalyst. The solid catalyst is calculated to be 1.17 weight
percent titanium on a solvent-free basis and the molar ratio of
triisobutyl aluminum to titanium was 12/1.
Example 2
A solid catalyst component was prepaxed according to
the procedure described in Example 1, except that 20 grams of X~NA
was used and no cyclohexane was added. An ethylene polymeri~atio
test was conducted at 105C. and 550 psig using 0.0~33 g of solid
catalyst and a 6/1 molar ratio of TIBAL to titanium. The hourly
.: .
catalyst reactivity was 920 g/~ and the hourly reactivity based
30 on titanium was 105,000 g/g. The product polyethylene was predom--
inantly in the form of particles 1 to 2 centimeters in diameter,
-12~
9~
together with a minor ~mount of f.ragmerlts produced by the reactor
agitator. The bulk dcnsity of the prod~lct was a desirabl~ hi~h
0.30 g/cm3 and no product particle~, adtlered to thc reaGtor wal.l.
E.~ample 3
A quan-tity of XMNA graf~ was ground to approxima~el~ 30
mesh in'a Wiley-type laboratory mi.ll. 10 grams o the resultin~
powder was then incorporated in a solld catalyst by the procedure
of Example 1. 0.1656 g of solid eatalyst was used in an ethylene
polymerization test with 1.0 ml (0.92 mmole) TIBAL solution. The
Al/Ti mole ratio was 22.3/1. The polymerization r~action was
condueted at 105C. and 550 psiq.
In this test, the total hourly catalyst reactivity was
~00 g/g and the titanium reactivity was 77,200 g/g/hr. The
product polyethylene was in the orm of particles 3-5 mm i,n dia~
meter, and none adhered to the reactor walls. With reference
to Exàmple 2, it is apparent that reduction in carrier size effects
a reduetion in product particle size. The product bulk density
was again 0.3 g/cm3.
Example 4
The carrier used in this example was XMNA graft yround
by a cryogenic technique and sieved. Only particles which passed
through a 140 mesh sieve were retained for use in the catalyst.
10 ~rams of XMN~ particles was added to a nitrogen purged flas~,
as in Example 1. 10 ml of ethyl aluminum sesquichloride solution
and 5 ml of the dibutyl magnesium/trle-thyl aluminum comple,c sol.~l-
tion of Example 1 were rapidly introduced while stirring, followecl
by introduction of 1.0 ml titanium tetraisopropoxide fo~L- a titan-
ium content of 1.17 weight percent on'a solvent-free basis. The
solvent was evaporated as in Example 1.
~ 0.0905 g solid catalyst was used in an ethylene polyMer
ization test under conditions i.dentical to those of E:cample 1,
13- :
c
~'2~
except that the mole ratio o~ TIBAL to tit~nium was 26/1. The
total catalyst reactivity w~s found to be 860 g/tJ/hr with a titanium
reactivity of 179,000 y/g/hr.
Example 5
A further polymerization test was made wi-th the catalyst
and reactants of Example 4, with the weiyht of solid catalyst heing
0.0352 g and with a mole ratio o~ TIBAL to titanium of 25/1. The
test was conducted at 105C. and 550 psig. The total catalyst
reactivity was 1160 g/g/hr and the titanium reactivity was 260,000
g~g/hr. The average particle size of the product was less than
about 1 mm, with the bulk density again being 0.3 g/cm , providing
a further illustration o~ the ef~ect of carrier particle size on
product particle size. (See Examples 2 and 3.)
Examples 6-9
A supported catalyst was prepared from cryogenically
ground Xk~A graft as described in Example 4. A series of four
polymerization tests was conducted with this catalyst using a
TIBAL to titanium mole ratio of about 25/1 and a polymerization
temperature of 107C. After the addition of solid catalyst and
TIBAL, iso~utane was introduced into the closed reaction vessel,
followed by ethylene. In three runs, hydrogen was added to the
reactor to increase the pressure by the amount stated below
followed by more ethylene to maintain the pressure at 550 p5ig.
~he resulting reactivities are given below:
Catalyst Hourly Reactivity
Exam. Hydrogen Total (g/g/hr)
No.Added Catalyst Titanium HLMI MI
6 0 1620 280,500 0.1 --
7100 psi~ 4~0 76,500 -- 6.
8 75 psi~ 710 ~3,300 -- ~.0
9 S0 psig ~60 115,600 -- 1.6
C ~
-14;-
... . . . .. ~ . , . . . _ .. . .. .. . .... . . . . . . . . . . .. . . . . . .
The nul~er of vinyl yroups in the product o~ Example 7was found to be 0.40/2000 carbon atoms. This example illustrates
that the melt index of product polyethyl~ne i~ directly relatcd
to hydroyen partial pressure in the ~eaction sy~tcm. Moreover,
vinyl unsaturation of the product is shown to be desirably low,
thereby increasing the resistance of the product polymer to
oxidative degradation under processing conditions.
Examples 10-11
The solid catalyst used in these examples ~7as the same
as used in Examples 6-9. The co-catalyst was a mixture of TI~3AL
and die-thylzinc ~DEZ). In each run, 50 psiy partial pressure of
hydroyen was added to the reactor and the temperature and total
pressure were maintained at 109C. and 55a psig, respectively.
The results are given below:
Catalys-t Hourly Reactivity
Exam. ~ /g~hr~
No.Co-catalyst Catalyst Titanium MI
0.43 mmole TIBAL 820 161,200 1.3
+ 0.17 mmole DEZ
2Q 11 0.18 mmole TIBAL 310 73,500 1.8
~ 0.18 mmole DEZ
In Exc~mple 10, the wei~ht of solid catalyst was Q.0786
g and 0.0498 g of catalyst was used in Example 11. The titanium
weight percentage was 1.17~ in each case. These examples show
that a mixture of alkyl zinc and aluminum compounds may be used as
a co-catalyst without siynificantly affectin~ the melt index of the
product polyethylene.
Example l?
The carrier of this example was a polyolefin powder with
an impact modi~ier generally used in rotational molding applications.
--lg:'--
.. . .. . . ... ... . . .. .. . . ... . . ... . .. . . ..
~zs~
The carrier had a density of abo~lt 0.950 g/cm3 and ~ melt index
of 6.5. Ten grams of carrier was mixed with ~thyl ~luminum
sesquichloride, dibutyl magn~sium/triethyl aluminum complex
solution and titanium tetraisopropoxide, as descr;bed ih ExamplP
4. After evaporation of solvent as described in Example 1,
0.0718 g of the resulting solid catalyst and 0.42 ml of TIBAL
solution (0.92M in heptane) were introducecl to a polymerization
vessel and an ethylene polymerization was conducted at 105~C.
and a total pressure of 550 psig with 50 psig hydrogen partial
pressure.
The reaction was continued ~or 90 minutes to yield
160 grams of polyethylene particles having a bulk density of
0.33 g/cm . The hourly reactivity was 185,600 g/s based on
titanium and 1700 g/g based on total catalyst. The melt index
was 4.8 and the high load melt index was 101. A relatively low
ratio of high load to normal melt index of 21 indicates a
relatively narrow molecular weight distribution and a desirably
low product shear sensitivity.
ample 13
A polymerization test was conducted with the solid
catalyst of Exclmple 120 A heptane solution of trihexylaluminum
was substituted for TIBAL as the co-catalyst. The molar ratio
of trihexylaluminum to titanium was 15O7/1. 50 psig of
hydrogen was added~ followed by the introduction of ethylene,
and the reaction was conducted at 105C. and 550 psig total
pressure. The hourly reactivity based on solid catalyst was
1200 g/g and 99,300 g/g based on titanium. The melt index was
2.4, the high load melt index was 79, and the ratio of high load
melt index to melt index was 32.8. The product bulk density was
0.26 g/cm3.
~16--
_ample 14
~ n ethylene polymeri2ation test was conducted with the
sol.id catalyst of Example l2. The co-ccl-talyst was diisobutyl
aluminum hydride in molar ratio to titanium of 15.7/1. The
polymerization conditions were identical to those of Example 9.
The hourly reactivity based on solid catalyst was 1010 g/g and
84,500 g/g based on titanium. The melt index was 3.7 and the
high load melt index was 95.1, for a ratio of high to normal
melt index of 26~ The product bulk density was 0.31 g/cm3.
Example 15
In this example, the carrier was a sample of the
cryogenically ground XMNA gra~t of Examples 6-9. 10 grams of the
XMNA graft was charged to an N2 purged flask and air was removed,
followed by addition of 1.0 ml of titanium tetraisopropoxide.
The mixture was then heated with a hot air gun under N2 purge
until condensation of liquid on the upper portion of the 1ask
ceased. 10 ml of a heptane solution of ethyl alwnin~
sesquichloride (15.4 mmoles Al) and 10 ml of a heptane solution
of dibutyl magnesium/aluminum complex (4.5 mmoles Bu2Mg and
0.75 mmoles Al) were added. Solvent was evapora-ted by bath
heating of the catalyst at 100C. for 30 minutes under an N2
purge to result in a solvent-free solid catalyst.
In an ~thylene polymeri~ation test, 0~0457 g of solid
catalyst was mixed with 0.27 ml ~0.25 mmole) of TIB~L solution and
50 psig hydrogen was added as previously descrihed. The reaction
was run for 150 minutes at 105C. and a total pressure of 550
psig. The hourly yield was 1050 g/g based on solid catalyst and
88,000 g/g hased on titanium.
A sample of the polymer was pyrolized under standard con-
ditions to leave an ash of 60 ppm~ This ash level is satisfactoryfor all commercial applications7 and thus it is demonstrated tha~
-17-
q
.. .... ... .... . . ... .... ....... . . ..... .... .... .. . . . ..... ... ... . . . . ..
the removal of catalyst residues is unnecessary. It has been
~ound, however, that if the supported reaction product catalyst
e~ceeds ahout 30 weight percent of the total of the reaction
product and the polymeric carri~r, an unsatisfackory ash level
results
The melt index of the product was 2.7, the high load
melt index was 77, and the ratio of the two was 28.4/1. The
bul~ density was 0.31 g/cm and the number of vinyl groups was
0.4 per 2000 carbon atoms. This example illustrates that the
order of mixing of the three reagents with the carrier does not
affect catalytic activity. Other mixing sequences were also
tested with similar results.
Example 16
In this example a finely divided high density poly~
ethylene with an average particle size of about 20 microns was
used as the carrier. A 10 gram quantity of the powder was
introduced to a flask purged of air by stirring under an N2
stream for 30 minutes at room temperature. Three catalyst forming
reactants were added to the flask in the following order, while
agitation by a magnet bar continued:
tl) 10 ml of 25~ ethyl aluminum sesquichloride
in heptane;
(2) 10 ml of 10% dibutyl macJnesium-triethyl
aluminum complex in heptane; and
~3) a volume of pentane solution containin~ 0.1 ml
of titanium tetraisopropoxide
The solvent was evaporated by heating for 30 minutes at 90C.
undcr a flow of dry N2. The calcula-ted titanium concentration of
this material was 0.10 weight percent.
3.0 ml of a 25~ TIBAL solution per gram of solid catalyst
was added and a particle form ethylene polymeri~ation test
.
18-
was conducted at 105C. and a total pressure o 550 psig ~7ith S0
psig hydro~en. The total catalyst reactivity including the TIBAI,
was 1244 g/g/hral-dthe reactivity based on titani.um ~tas 1,525,000
g/g/hr. The melt index o ~he particle form product w~s 0.~0.
Example 17
-
A catalyst was prepared by usiny the XM~lA graft carrier
of Example 4. lO grams o~ the powder was purged witl N2 and
subsequently combined with 7.5 ml of ethyl aluminum sesquichloride
solution (5.8 mmoles in heptane), 6.5 ml of butyl ethyl magnesiurn
53.85 mmoles in heptane) and 0.6 ml of pentane solution containing
O.33 mmole of titanium tetraisopropoxide. The solvent was
evaporated by heating under N2 for 30 minutes at a temperature
of 90~C. The calculated titanium conten-t of this material was
0.11 weight percent.
An ethylene polymerization test was conducted as
previously-described at 105C. and 550 psig total pressure, with
75 psig hydrogen. The tntal catalyst reactivity was 1000 g/g/hr
and the reactivity with respect to titanium was l,170,000 ~/g/hr.
The melt index of the product polyethylene was 1.14.
All parts and percentages herein are by wei~ht.
Abbreviations used herein to identify chemical
ingredients and product characteristics include:
DEZ diethylzinc
HLMI - high load melt index
MI - melt index
TIBAL - triisobutylaluminum
XMNA - an X-methyl bicycln[2.2.1]hept-5-ene-2,3-
dicarboxylic acid anhydride ~rafted
polyethylene, as described in
U~S. Patent 3,873,643
--19--
.. . . . . .. .... ........ ...... ........
{~
S UPPLEMENTA~Y DI SCLOS URE
As disclosed in the prlncipal disclosure of this
application, the catalyst of the invention comprises the
reaction product oE (1) alkyl aluminum halide (2) a dialkyl
magnesium compound or complex and (3) a titanium alkoxide or
titanium alkoxide halide, supported on an organlc carrler as
described in the principal disclosure and used in -the pre~ence
of an alkyl aluminum co-catalyst.
The titanium compound however, may, in addition to
being an alkoxide or mixed alkoxide halide be a titanium halide.
Accordingly the titanium compound may be an alkoxide, mixed
alkoxide halide, or halide of the formula Ti(OR)nX4 n where R is
an alkyl group of 1 - 6 carbon atoms, X is a halogen atom, and n
is an integer between 0 and 4 inclusive.
Further the reaction product may be supported on an
organic carrier as described previously in the disclosure in the
presence of an organometallic co-catalyst of which the alkyl
aluminum compound is preferred.
The invention also comprehends, in accordance ~ith
the disclosure including this Supplementary Disclosure, a
supported olefin polymerization and co-polymexi~ation catalyst
active in the presence of an organometallic co-ca-talyst prepared
by mixing reactive materials comprising a lower alkyl aluminum
halide, a dialkyl magnesium compound and a reducible titanium
compound of the formula Ti(OR)nX4 n where R is an alkyl group,
x is a halogen atom, and n is an integer between 0 and 4,
inclusive, in the presence of a solvent and a particulate
organic polymer to form a reaction product supported on the
particles. The particulate organic polymer comprises a graft
copolymer of about 70 - 99.95 weight percent of a polyolefin
polymer and about 30 - 0.05 weight pexcent of at least one
monomer selected from the group consisting of polymeri~able
cyclic and polycyclic ethylenically unsaturated carboxylic
acids and carbo~ylic acid anhydrides, the solvent being
20--
~L12~
evaporated at a temperature which is less than the softening
temperature of the organic polymer.
The invention also comprehends the method of preparing
a supported olefin polymerlzation and copolymerization
catalyst active in the presence of an organometallic co-
catalyst comprising mixing reactive materials comprisiny a
lower alkyl aluminum halide, a dialkyl magnesium compound and
a reducible titanium compound of the formula Ti(OR)nX~ ~l
where R is an alkyl group, X is a halogen atom, and n is an
integer between 0 and 4, inclusive, in the presence of a
solvent and a particulate organic polymer consisting essential-
ly of a high density polyethylene which has chemically bonded
to it between about 0.05 and about 30 weight percent of an
organic carboxylic acid or acid anhydride to form a reaction
product supported on the particles, the solvent being evapora-ted
at a temperature which is less than the softening temperature
of the organic polymer.
Additional Examples of the invention follow:
Exam~le 18
10 g of microthene high density polyethylene powder
was added to a dry, nitrogen purged flask and agitated with a
magnet bar for one hour while maintaining the nitrogen purge.
The following reactants were added successively at room
temperature while agitating continued:
(1) 7.5 ml of 25~ ethyl aluminum sesquichloride in
heptane;
(2) 6.5 ml of 10~ of butyl ethyl magnesium in heptane;
and
l3) 0.10 ml of titanium tetrachloride.
The composition was stirred for a few minutes to give
a uniform color, followed by evaporation of the heptane solvent
2 1
~; ~
by immersion of the flask in an ethylene glycol bath for 30 min-
utes at 90C. under the nitrogen flow.
A quantity of the resultin~ catalyst was t~sted in a
batch reactor under par-ticl.e form conditions. The pol~meriY.aLion
temperature was 221F., and total pressure was maintalned at 5S0
psig with a hydrogen partial pressure of 50 psig. 9.2 mmol~s
of TIBAL co-catàlyst per gram of sol.id catalyst component was used.
The yield of part.icle form polyethylene based on the solid com-
ponent was 421 g/g/hr and the reactivity based on titaniu~l was
10 119,000 g/g/hr.
Example 19
.
A reaction mixture of titanium tetrachloride and titan-
ium tetraisopropoxide in amounts selected to result in an avera~e
composition corresponding to titanium diisopropoxide dichloride
was prepared, as follows. One milliliter (3.32 ~noles) of titall-
ium tetraisopropoxide was added to 18 ml of dry heptane under a
nitrogen atmosphere. 0.38 milliliter (3.38 mmoles) of titanium
tetrachloride was then added and a white precipitate foxmed. The
reaction mixture was maintained at room temperature for one hour.
10 g quantity o~ cryogenically ground XMN~ powder was
put into a dry, nitrogen purged flask. The powder was stirred
for one hour under the nitrogen purge, ancl the following were
addecl during sti.rring in the following order: .
(1) 7.5 ml of 25~ ethylaluminum sesquichlor.ide in heptane;
(2) 10.0 ml of an 8.9% solution of a magllesium/alulninum
complex of the formula (Bu2Mg)6 1(Et3~ n heptane;
and
(3) 2 0 ml of the above described titanium diisopropoxide
dichloride reaction mixture.
As soon as the third reactant was added, the flas~ was
immersed in a heating bath at 90C for 30 minutes and heptane was
evaporated under nitrogen purge.
- 22
~ - .
~Z9~
A quantity of the resulting catalyst was tested in a
batch reactor under particle form polymerization co~ditions at
215F. and a total pressure was 550 psig with 50 psiy hydrogen
partial pressure. 2.7 r~noles of TIB~L co-catalyst per grarn o~
solid XMN~ catalyst was used.
The polyethylene yield based on solid catalyst was
687 g/g/hr, and the reactivity based on titanium was ahout
254,000 g/g/llr. The product polyethylene was granular and of a
substantially uniform particle size.
All parts and percentages herein are by weight.
Abbreviations used herein to ldentify chemical ingred-
ients and product characteristics include:
DEZ - diethylzinc
HLMI - high load melt index
MI - melt index
TIBAL - Triisobutylaluminum
X~lNA - an X-methyl bicyclo[2.2.1]hept-5-ene-2,3-
dicarboxylic acid anhydride grafted
polyethylene, as described in U.S.
Patent 3,873,643
- 23 -
