Note: Descriptions are shown in the official language in which they were submitted.
112g9~8
This invention relates to a process for preparing a medium or
low density ethylene copolymer according to the vapour phase polymeriza-
tion procedure using a Ziegler-type catalyst of high activity.
Polyethylenes obtained by polymerization using a catalyst con-
sisting of a transition metal compound and an organometallic compound are
generally prepared according to the slurry polymerization process, and only
those having a density not lower than 0.945 are produced, which value is
considered to be the limit in order to prevent polymer deposition and
fouling on the inner wall or stirrer in the reactor interior at the time
of polymerization.
Medium or low density polyethylenes having a density below 0.945
g/cm are prepared mainly by the so-called high pressure process using a
radical catalyst. Quite recently, high-temperature solution polymerizations
using a Ziegler-type catalyst have also been tried. Copolymerizing ethylene
and other -olefins using a catalyst containing a vanadium compound as one
component has also been tried in order to prepare an elastomeric copolymer.
These polyolefin series plastics prepared according to the high
pressure process or high-temperature solution polymerization using a
Ziegler-type catalyst, and elastomers prepared using a vanadium compound-
containing catalyst, exhibit superior performances and are used in variousapplications. For example, low density polyethylenes prepared according
to the high pressure process are superior in transparency and flexibility,
and so are used in the field of films. Elastomers resulting from the poly-
merization of ethylene and propylene, or as the case may be, dienes, e.g.,
dicyclopentadiene and ethylidenenorbornene, using a vanadium-containin~
catalyst, namely EPM and EPDM, have no unsaturated bond in the main chain,
for which reason they provide elastomers superior in heat- and weathering-
resistance, and so are often used for tires and tubes.
However, polyethylenes prepared by the high pressure process
are disadvantageous in that they have low melting point, and have low
-- 1 --
11249~8
stiffness, that is, they are inferior in heat resistance, and also in
strength. Medium density polyethylenes prepared according to the high-
temperature solution polymerization process are inferior in transparency
and give a sticky impression.
In order to provide an improvement in the resistance to environ-
mental stress cracking, it is necessary to impart an elastomeric character
to plastics. In order to take advantage of their thermoelasticity, it
is necessary to impart strength based on crystallinity to elastomers. It
is a well-known fact, however, that if both components are mixed together
for such purpose, it will result in deterioration of some physical
properties, e.g., tensile strength and rigidity.
However, if a soft or semi-hard resin is prepared, which resin
itself is neither a crystalline plastic nor an elastomer, but has an
intermediate structure and exhibits a high grade of elongation, then such
resin itself will become suited for the above-mentioned purpose. It is
also possible to blend it with other plastics, thereby imparting an
elastomer character thereto and improving the properties of the plastics.
A production method has been reported for a resin which exhibits
such an intermediate physical property. Many problems have to be solved
before such production methods can be applied on an industrial scale.
For example, Japanese Patent Publication No. 11028/71 discloses
a solution polymerization using an aromatic hydrocarbon solvent for the
preparation of an ethylene-C~ -olefin copolymer. This method, however,
suffers the disadvantage that the catalyst efficiency is poor and, because
it is a solution polymerization, it is troublesome to separate and recover
the solvent.
Japanese Patent Publication No.26185/72 proposes the copolymeriza-
tion of ethylene and an ~ -olefin using an aliphatic hydrocarbon halide as
a solvent. This method suffers the disadvantage that a large amount of a
low molecular weight copolymer is produced, probably because the hydrocarbon
llZ4948
halide solvent acts as a molecular weight adjuster, so that an article
formed thereof is sticky on the surface. That patent publication also
discloses the use of lower hydrocarbons of C3 to C5 as a solvent. In the
polymerization using these solvents, however, it is necessary to raise
the reaction pressure due to the vapour pressure from the solvents. In
the solvent recovery step, moreover, it is necessary to compress and cool
the solvent for its liquefaction.
Furthermore, in Japanese Patent Laying Open Print No. 41784/76,
a slurry copolymerization of ethylene and butene-l is disclosed. In this
case, there are found drawbacks exist, namely that the polymerization
temperature and the composition of the starting materials must be specified
very accurately and at values outside the specified range the slurry
becomes milky or mushy, which makes reactor operation and slurry transport
difficult.
The above-mentioned drawbacks are based on the low catalyst
activity, the troublesomeness of solvent separation and recovery because
of a solution polymerization, a large quantity production of a low mole-
cular weight copolymer due to chain transfer with solvent, and the neces-
sity of specifying the polymerization temperature and the composition of
starting materials in slurry polymerization to maintain the slurried state
of polymer. The need to provide an extremely large amount of comonomer is
a further drawback encountered in the above-proposed methods.
Recently, it has been taught that a catalyst system prepared by
first attaching a transition metal to a magnesium-containing solid carrier,
e.g., MgO, Mg(OH)2, MgC12, MgCO3, or Mg(OH)Cl, and then combining it with
an organometallic compound, can serve as a catalyst of a remarkably high
activity in olefin polymerization. It is also known that the reaction
product of an organomagnesium compound, e.g., RMgX, R2Mg or RMg(OR) and a
transition metal compound can act as a high polymerization catalyst for
olefins (see, for example, Japanese Patent Publication No. 12105/64,
-- 3 --
1124948
Belgian Patent No. 742,112, Japanese Patent Publications Nos. 13050/68 and
9548/70).
However, even if a slurry polymerization or solution polymeriza-
tion is carried out using such a high activity catalyst with carrier with
a view to attaining reduction in density of polymer, the foregoing drawbacks
heretofore have not been completely solved.
By a broad aspect of this invention, a process is provided for
preparing an ethylene-C~~olefin copolymer having a density of 0.850 to
0.945, which comprises copolymerizing ethylene and 1 to 40 mol% thereof of
~<-olefin having 5 to 18 carbon atoms in a substantially solvent-free vapour
phase condition and in the presence of a catalyst comprising a solid sub-
stance and an organoaluminum compound, the solid substance containing
magnesium and at least one of titanium and vanadium.
By a variant thereof, the solid substance is obtained by attaching
the at least one of a titanium compound ar.d a vanadium compound to the
magnesium-containing inorganic solid carrier.
By another variant, the solid substance is a reaction product of
the organoma~nesium compound and the at least one of a titanium compound
and a vanadium compound.
By a variation thereof, the magnesium-containing inorganic solid
carrier is selected from the group consisting of metallic magnesium, mag-
nesium hydroxide, magnesium carbonate, magnesium oxide and magnesium chloride.
By a further variation, the magnesium-containing inorganic solid
carrier is selected from the group consisting of a double salt, a double
oxide, a carbonate, a chloride and a hydroxide containing magnesium atom
and a metal selected from the group consisting of silicon, aluminum and
calcium.
By still a further variation, the magnesium-containing inorganic
solid carrier is further treated or reacted with a material selected from
the group consisting of an oxygen-containing compound, a sulfur-containing
11249~8
compound, a hydrocarbon and a halogen-containing substance.
By yet another variation, the at least one of the titanium and
the vanadium compound is a halide, alkoxyhalide, oxide or halogenated
oxide of at least one of titanium and vanadium.
By a variation thereof, the organomagnesium compound is a compound
represented by the general formula RMgX, R2Mg and RMg(OR), wherein R is an
organic radical and X is halogen.
By another variation, the at least one of the titanium compound
and the vanadium compound is used as the addition product with an organo-
carboxylic acid ester in the preparation of the solid substance.
By yet another variation, the magnesium-containing inorganic
solid carrier is contacted with an organocarboxylic acid ester before its
use in the preparation of the solid substance.
By another variant, the organoaluminum compound is used as the
addition product with an organocarboxylic acid ester.
By a further variant, the catalyst system is prèpared in the
presence of an organocarboxylic acid ester.
By yet a further variant, the copolymerization is carried out at
a temperature in the range of from 20 to 110C. and at a pressure in the
range of from atmospheric to 70 kg/cm G.
By yet another variant, the copolymerization is carried out in
the presence of hydrogen.
By a further variant, the catalyst system is contacted beforehand
with an~C-olefin for 1 minute to 24 hours at a temperature in the range of
from 0 to 200~C. and at a pressure in the range of from -1 to 100 kg/cm G,
and thereafter the copolymerization is carried out.
By yet another variant, the CC-olefin to be copolymerized with
ethylene is a member selected from the group consisting of pentene-l,
hexene-l, 4-methylpentene-1, heptene-l, octene-l, nonene-l, decene-l,
dodecene-l, tridecene-l, tetradecene-l, pentadecene-l, hexadecene-l,
1~24948
heptadecene-l, octadecene-l, and mixtures thereof.
Having made comprehensive studies about the foregoing technical
problems, it has now been discoverecl that the various drawbacks associated
with the solution or slurry polymerization, e.g., low polymerization
activity, polymer adhesion, low bulk density and the production of coarse
polymer particles, may be obviated by the process of aspects of this inven-
tion. According to the process of an aspect of this invention, a vapour
phase polymerization reaction can be conducted extremely stably, and be-
sides, the catalyst removing step can be omitted. Accordingly, a vapour
phase polymerization process is provided for the copolymerization of ethy-
lene and an ~C-olefin having 5 to 18 carbon atoms which as a whole is very
simple. Furthermore, the copolymer of ethylene and an ~ -olefin of C5 to
C18 prepared according to the process of an aspect of this invention is
very superior in strength, impact resistance, transparency and resistance
to environmental stress cracking, though a detailed description on this
respect will be given hereinafter.
In more particular terms, this invention thus provides a process
for preparing an ethylene-~-olefin copolymer having a density of 0.850 to
0.945, wherein a mixture of ethylene and 1 to 40 mol% thereof of an
~-olefin having 5 to 18 carbon atoms is contacted in vapour phase condition
with a catalyst comprising a solid substance and an organoaluminum compound,
the solid substance containing magnesium and at least one of titanium and
vanadium. It has been found that, according to the process of aspects of
this invention, that is, i-f a vapour phase polymerization is carried out
using ethylene and an ~-olefin of C5 to C18 in a quantitative ratio within
the range specified herein and in the presence of a catalyst comprising a
solid substance and an organoaluminum compound, the solid substance con-
taining magnesium and at least one of titanium and vanadium, a vapour
phase polymerization reaction is effected in extremely high activity and
very stably. Despite the resulting polymer having stickiness, the process
11~49~8
provides a reduced production ratio of coarse or ultra-fine particles,
improved particle properties, high bulk density and minimized adhesion to
reactor and conglomeration of polymer particles. It is quite unexpected
and surprising that, according to the process of aspects of this invention,
not only can a vapour phase polymerization reaction be carried out
extremely smoothly, but also medium and low density ethylene copolymers can
be obtained easily.
In the process of aspects of this invention, moreover, the
copolymerization reaction can be conducted even at a relatively low tem-
perature easily to provide medium or low density ethylene polymers. Thisis very advantageous when viewed from the standpoint of adhesion to reactor
and conglomeration of product. This point is also an advantage of the
invention. Furthermore, the process of aspects of this invention easily
provides medium or low density ethylene copolymers having a high melt
index, and this point is another advantage of the invention. Because of
these advantages, the copolymer can be obtained efficiently by vapour
phase polymerization.
~ -olefins of C5 - C18 to be copolymerized with ethylene in the
process of aspects of this invention function to adjust the density and
molecular weight of copolymer, and the resulting copolymer is superior in
transparency, appearance and gloss. Its flexibility and elasticity are
excellent at low temperatures and at room temperatures. Despite such an
excellent flexibility, the resulting polymer exhibits equal or even
superior strength to that of ordinary polyolefins. The copolymer obtained
according to the process of aspects of this invention contains few unsatu-
rated bonds, residual catalyst or other impurities, and thus is very
superior in weathering- and chemicals-resistance, as well as electrical
characteristics, e.g., dielectric loss, break-down voltage and resistivity.
The copolymer exhibits very superior characteristics with respect to resis-
tance to impact and to environmental stress cracking. Having these
llZ4~48
characteristics, the copolymer prepared according to the process of aspectsof this invention can be formed into films, sheets, hollow containers,
electric wires, and various other products by known forming procedures,
e.g., extrusion moldingS blow molding, injection molding, press forming
and vacuum forming. Films prepared from the copolymer have excellent
strength, elongation, transparency, anti-blocking property, heat-sealing
property and flexibility. What is worthy of special mention, however, is
that according to the process of aspects of this invention, the hexane
extract is very small in quantity and so a copolymer is provided which
satisfies the "U.S. Food Medicines Adminstration Standard on Extracts to
be Contacted with Food" (n-hexane extract at 50C. should be below 5.5% by
weight), and the copolymer can be safely used as food packing film. Since
the copolymer is superior in transparency, stiffness and resistance to
environmental stress cracking, it is also suited to blow molding, Further-
more, the copolymer is a very superior resin also for use as an electric
wire because of excellent electrical characteristics and easy application
to extrusion molding.
In addition, the copolymer prepared according to the process of
aspects of this invention contains olefins as components, so is very
similar in structure and composition to known polyolefin resins. It can
be adjusted to be low in crystallinity, for which reason it is compatible
with other polyolefin resins, and is specially compatible with high and
low density polyethylene, polypropylene, and ethylene-vinyl acetate
copolymers. By blending the copolymer with these resins, it is possible
to improve resistance to impact, to cold and to environmental stress
cracking.
The catalyst system used in the process of aspects of this inven-
tion comprises the combination of a solid substance and an organoaluminum
compound, the solid substance containing magnesium and at least one of
titanium and vanadium. The solid substance is obtained by attaching at
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11~4948
least one of a titanium compound and a vanadium compound, by a known pro-
cedure, to an inorganic solid carrler typical of which are metallic
magnesium, magnesium hydroxide,-magnesium carbonate, magnesium oxide and
magnesium chloride; or double salts, double oxides, carbonates, chlorides,
or hydroxides containing a metal selected from the group consisting of
silicon, aluminum and calcium, and magnesium atoms; further, these
inorganic solid carriers may be treated or reacted with an oxygen-containing
compound, a sulfur-containing compound, a hydrocarbon or a halogen-containing
sub~stance.
As the at least one of a titanium compound and a vanadium compound
referred to herein,mention may be made of halides, alkoxyhalides, oxides
and halogenated oxides of at least one of titanium and vanadium. Examples
are tetravalent titanium compounds, e.g., titanium tetrachloride, titanium
tetrabromide, titanium tetraiodide, monoethoxytrichlorotitanium, diethoxy-
dichlorotitanium, triethoxymonochlorotitanium, tetraethoxytitanium, mono-
isopropoxytrichlorotitanium, diisopropoxydichlorotitanium and tetraiso-
propoxytitanium; various titanium trihalides obtained by reducing titanium
tetrahalides with hydrogen, aluminum, titanium or an organometallic com-
pound; trivalent titanium compounds obtained by reducing various tetra-
valent alkoxytitanium halides with an organometallic compound; tetravalent
vanadium compounds, e.g., vanadium tetrachloride; pentavalent vanadium
compounds, e.g., vanadium oxytrichloride and orthoalkylvanadate; and tri-
valent vanadium compounds, e.g., vanadium trichloride and vanadium
triethoxide.
Among these titanium compounds and vanadium compounds, tetravalent
titanium compounds are especially preferred.
The catalyst which may be used in the process of aspects of this
invention comprises the combination of a solid substance, which is obtained
by attaching at least one of a titanium compound and a vanadium compound
to the solid carrier exempllified previously, and an organoaluminum compound.
948
By way of illustrating preferred catalyst systems, mention may
be made of the combination of an organoaluminum compound with the follow-
ing solid substances (the R in the following formulae represents an
organic radical and X represents halogen): MgO~RX-TiC14 system (see
Japanese Patent Publication No. 3514/76), Mg-SiC14-ROH-TiC14 system (see
Japanese Patent Publication No. 23864/75), MgC12-Al(OR)3-TiC14 system
(see Japanese Patent Publications Nos. 152/76 and 15111/77),
MgC12-SiC14-ROH-TiC14 system (see Japanese Patent Laying Open Print No.
196581/74), Mg(OOCR)2-Al(OR)3-TiC14 system (see Japanese Patent Publication
No. 11710/77), Mg-POC13-TiC14 system (see Japanese Patent Publication No.
153/76), and MgC12-AlOCl-TiC14 system (see Japanese Patent ~aying Open
Print No. 133386/76).
To illustrate another example of catalyst system which may be
suitably used in the process of aspects of this invention, mention may be
made of the combination of the reaction product of an organomagnesium com-
pound, e.g, a Grignard compound and at least one of a titanium compound
and a vanadium compound, and an organoaluminum compound. As the organo-
magnesium compound there may be used those represented by the general
formulae RMgX, R2Mg and RMg(OR) wherein R is an organic radical and X is
halogen, and ether complexes thereof, or these organomagnesium compounds
after modification with other organometallic compounds, e.g., organosodium,
organolithium, organopotassium, organoboron, organocalcium and organozinc.
Such catalyst systems, for example, comprise the combination of
the following solid substances and an organoaluminum compound;
RMgX-TiC14 system (see Japanese Patent Publication No. 39470/75),
RMgX- Cl - ~ OH - TiC14 system (see Japanese Patent Laying Open
Print No. 119977/74), RMgX- ~ OH - TiC14 system (see Japanese
-- 10 --
11~4948
Patent Laying Open Print No. 119982/74).
In these catalyst systems, at least one of a titanium compound
and a vanadium compound may be used as the addition product with an organo-
carboxylic acid ester. Furthermore, the magnesium-containing solid carriers
previously exemplified may be contacted, before use, with an organocar-
boxylic acid ester. Also an organoaluminum compound may be used as the
addition product with an organocarboxylic acid ester. Furthermore, in
every case in the process of aspects of this invention, the catalyst systems
used therein may be prepared in the presence of an organocarboxylic acid
ester and this causes no troublè.
As the organocarboxylic acid ester referred to herein. there may
be employed various aliphatic, alicyclic and aromatic carboxylic acid
esters, preferably aromatic carboxylic acids of C7 to C12, e.g., alkyl-
esters, e.g., methyl and ethyl of benzoic acid, anisic acid and toluic acid.
Examples of organoaluminum compounds which may be used in the
process of aspects of this invention are those represented by the general
formulae R3Al, R2AlX, RAlX2, R2AlOR, RAl(OR)X and R3A12X3 wherein R is Cl
to C20 alkyl or aryl, X is halogen and R may be the same or different, e.g.,
triethylaluminum, triisobutylaluminum, trihexylaluminum, tricotylaluminum,
diethylaluminum chloride, ethylaluminum sesquichloride, and mixtures
thereof.
The amount of an organoaluminum compound to be used in the process
of aspects of this invention is not specially limited, but usually it may
range from 0.1 to 1000 mols per mol of a transition metal compound.
In the polymerization reaction, a mixture of ethylene and an
-olefin of C5 to C18 is allowed to polymerize in the vapour phase using a
known reactor, e.g., a fluidized bed or agitation vessel.
The polymerization conditions involve temperatures ranging
usually from 20 to 110C., preferably from 50 to 100C., and pressures
from atmospheric pressure to 70 kg/cm G, preferably from 2 to 60 kg/cm G.
11249~8
Adjustment of the molecular weight can be made by changing the polymeriza-
tion temperature, the molar ratio of catalyst or the amount of comonomer,
but the addition of hydrogen into the polymerization system is more effec-
tive for this purpose. Of cource, the process of aspects of this invention
can be applied, without any trouble, to two or more stage polymerization
reactions involving different polymerization conditions, e.g., different
hydrogen and comonomer concentrations and different polymerization tempera-
tures.
In the process of aspects of this invention, moreover, the fore-
going catalyst system may be contacted with an ~-olefin before its use in
the vapour phase polymerization reaction whereby it is possible to improve
the polymerization activity and to assure a more stable operation than in
the untreated condition. Various <-olefins are employable in the above
treatment, preferably those having 3 to 12 carbon atoms and more preferably
those having 3 to 8 carbon atoms, typical of which are propylene, butene-l,
pentene-l, 4-methylpentene-1, heptene-l, hexene-l, octene-l, and mixtures
thereof. The temperature and time for such contact treatment for the cata-
lyst used in the process of aspects of this invention with an ~-olefin can
be selected in wide range, for example, 0 to 200C., preferably 0 to 110
110C., and 1 minute to 24 hours.
The amount of an ~ -olefin to be brought into contact with the
catalyst can also be selected in wide range, but usually it ranges from
1 g to 50,000 g, preferably 5 g to-30,000 g, per gram of the solid substance
and it is desired that 1 g to 500 g of the o~-olefin per gram of the solid
substance be reacted. The pressure in such contact treatment can be
optionally selected, but desirably it ranges from -1 to 100 kg/cm G.
In the above treatment of the catalyst with an ~-olefin, the
total amount of an organoaluminum compound may be first combined with the
solid substance and then contacted with the c~-olefin or alternatively part
of the organoaluminum compound may be combined with the solid substance,
- 12 -
l~Z49~
then contacted with the ~-olefin and the remaining portion of the organo-
aluminum compound may be separately added in the vapour phase polymeriza-
tion of ethylene. Furthermore, the catalyst may be contacted with an
C-olefin in the presence of hydrogen gas, or other inert gas, e.g.,
nitrogen, argon or helium.
c~ -olefins to be copolymerized with ethylene in the process of
aspects of this invention are those having 5 to 18 carbon atoms and they
may be of a straight chain or branched. Examples are pentene-l, hexene-l,
4-methylpentene-1, heptene-l, octene-l, none-l, decene-l, undecene-l,
dodecene-l, tridecene-l, tetradecene-l, pentadecene-l, hexadecene-l, hepta-
decene-l, octadecene-l and mixtures thereof.
The amount of an ~ -olefin to be copolymerized with ethylene in
the process of aspects of this invention should be in the range of from 1
to 40 mol% based on the amount of ethylene. Outside this range, it is
impossible to obtain the product of aspects of this invention, namely an
ethylene- ~-olefin copolymer having a density of 0.850 to 0.945. The
amount of such ~<-olefin can be adjusted easily according to the composition
ratio of the vapour phase in the polymerization vessel.
In the process of aspects of this invention, moreover, various
dienes may be added as termonomers in the copolymerization reaction, e.g.,
butadiene, 1,4-hexadiene, 1,5-hexadiene, vinylnorbornene, ethylidenenorb-
ornene and dicyclopentadiene.
Working examples of aspects of this invention are described below,
but it is to be understood that these examples are for the purpose of
illustrating the operation of the invention.
Example 1
1 kg of anhydrous magnesium chloride, 50 g of 1,2-dichloroethane
and 170 g of titanium tetrachloride were subjected to ball milling for 16
hours at room temperature in a nitrogen atmosphere to allow the titanium
compound to be attached to the carrier. The resulting solid substance
11;~4948
contained 35 mg of titanium per gram thereof.
A stainless steel autoclave was used as the apparatus for the
vapour phase polymerization, and there were used a blower, a flow rate
adjuster and a dry cyclone to form a loop, and the temperature of the
autoclave was adjusted by passing warm water through the jacket.
To the autoclave adjusted to 85C. were fed the solid substance
prepared above and triethylaluminum at the rates of 250 mg/hr and 50 mmol/hr,
respectively, and also introduced were ethylene, 4-methylpentene-1 and
hydrogen while making adjustment so that the 4-methylpentene-1/ethylene
ratio (in molar ratio) in the vapour phase in the autoclave was 0.035 and
the hydrogen gas pressure was 22% of the total pressure, and a polymeriza-
tion was made while the gases in the system were circulated by the blower.
The resulting ethylene copolymer had a bulk density of 0.395, a melt index
(MI) of 1.4 and a density of 0.930~ the greater part of which was composed
of powders with particle sizes in the range of from 250 to 500~. The
polymerization activity was high, 173,500 g copolymer/g Ti.
After continuous operation for 10 hours, the autoclave was
opened and its interior was checked to find it was clean with no polymer
adhesion to the inner wall and stirrer. That is, it is apparent that a
very stable operation is assured according to the process of an aspect of
this invention, though it was unattainable in the slurry polymeri~ation
shown in Comparative Example 1 as will be referred to hereinafter.
The resulting copolymer was formed into a film 400 mm in fold
diameter by 30~u thick through a 75 mm~ inflation film forming die in a
50 mm~ extruder, which film was superior in strength and in transparency.
The film was subjected to extraction with hexane at 50C. for 4
hours to give 2.10% extract.
Comparative Example 1
Using the same catalyst as that used in Example 1 and hexane as
solvent, a continuous slurry polymerization was conducted at 85C.
11~4948
Hexane as polymerization solvent containing 5 mg/~ of the solid
catalyst and 1 mmol/~ of triethylaluminum was fed at the rate of 40 ~/hr,
and also fed were ethylene, 4-methylpentene-1 (20 mol% of ethylene) and
hydrogen at the rates of 10 kg/hr, 6 kg/hr and 2Nm3/hr, respectively, and
a continuous polymerization was made on condition that the residence time
was 1 hour. The resulting copolymer was continuously withdrawn as slurry.
In 3 hours, the polymer slurry withdrawing pipe was obturated and the
polymerization was compelled to be discontinued.
The interior of the reactor was checked to find that the hexane
layer was emulsified and a large amount of a rubbery polymer adhered to the
gas-liquid interface and also to the polymer withdrawing pipe.
The copolymer prepared above had a bulk density of 0.248, MI of
0.74 and a density of 0.932.
Example 2
Polymerization was carried out in the same manner as in Example 1
except that the 4-methylpentene-1/ethylene ratio was 0.14 and the hydrogen
gas pressure was 15% of the total pressure.
The resulting ethylene copolymer had a MI of 2.3, a bulk density
of 0.384 and a density of 0.896, and the polymerization activity was
147,000 g copolymer/g Ti.
After continuous operation for 10 hours, the interior of the
reactor was checked to find no polymer adhesion to the inner wall and
stirrer.
The copolymer after subjected to press forming was transparent,
having a breaking point strength of 193 kg/cm2 and an elongation of 630%.
Example 3
Polymerization was carried out in the same manner as in Example 1
except that hexene-l was used in place of 4-methylpentene-1.
The resulting ethylene copolymer had a bulk density of 0.399, MI
of 1.3 and a density of 0.933, and the polymerization activity was 186,500
- 15 -
1124'9~8
g copolymer/g Ti.
After continuous operation for 10 hours, the polymerization was
discontinued and the reactor inside was checked to find no polymer adhesion.
The resulting polymer was formed into an inflation film 30~u
thick, which film was superior in strength and in transparency. The hexane
extract of the film was 0.17%.
Example 4
830 g of anhydrous magnesium chloride, 50 g of aluminum oxychlor-
ide and 170 g of titanium tetrachloride were subjected to ball milling for
16 hours at room temperature in a nitrogen atomsphere. The resulting solid
substance contained 41 mg of titanium per gram thereof.
The solid substance prepared above and triethylaluminum were fed
at the rates of 200 mg/hr and 50 mmol/hr, respectively, and a polymeriza-
tion was made at 85C. in the same way as in Example 1, with the proviso
that the comonomer to be copolymerized was hexene-l, the hexene-l/ethylene
ratio in the vapour phase was 0.07 and the hydrogen gas pressure was 16%
of the total pressure.
After continuous operation for 10 hours, the interior of the
autoclave was checked to find no polymer adhesion.
The resulting copolymer had a bulk density of 0.408, MI of 1.1
and a density of 0.915, and the polymerization activity was very high,
194,500 g ethylene-copolymer/g Ti.
The copolymer was fDrmed into a film 400 mm in fold diamter by
30J~ thick in the same manner as in Example 1, which film was superior in
both strength and transparency. The hexane extract of the film was 0.36%.
Comparative Example 2
Using the same catalyst as that used in Example 2 and n-paraffin
as solvent, a solution polymerization was carried out. That is, n-paraffin
containing 25 mg/~ of the solid substance prepared in Example 2 and
5 mmol/~ of triethylaluminum was fed at the rate of 40Q /hr, and also
- 16 -
~lZ49~8
fed were ethylene, hexene-l and hydrogen at the rates of 10 kg/hr, 6 kg/hr
and 550 N~ /hr, respectively and a continuous polymerization was made at
160C. on condition that the residence time was 1 hour. The resulting
ethylene copolymer had a MI of 0.34 and a density of 0.947, and the poly-
merization activity was 7,800 g copolymer/g Ti.
Thus in the case of a solution polymerization, despite a large
amount of hexene-l used, the polymer density is not lowered so much and
the polymerization activity is low, it being apparent that this is an
example of inefficient polymerization.
Example 5
Copolymerization was carried out in the same manner as in Example
4 except that the hexene-l/ethylene ratio was 0.28 and the hydrogen gas
pressure was 10% of the total pressure.
The resulting ethylene copolymer had a MI of 1.9, a bulk density
of 0.379 and a density of 0.870, and the polymerization activity was
171,000 g copolymer/g Ti.
In 10 hours, the supply of the starting gases was stopped to
terminate the polymerization reaction and the reactor inside was checked
to find no polymer adhesion therein.
The resulting ethylene-hexene-l copolymer was subjected to press
forming and the formed article was high in transparency, having a breaking
point strength of 180 kg/cm and an elongation of 650%.
Example 6
A continuous polymerization was carried out in the same manner
as in Example 4 except that an equimixture of hexene-l, octene-l and
decene-l (trade name "DIALEN 610") was used as comonomer in place of
hexene-l.
The resulting ethylene copolymer had a bulk density of 0.395,
MI of 1.2 and a density of 0.918, and the polymerization activity was
190,300 g copolymer/g Ti.
1~24948
The copolymer was formed into an inflation film 30 ~ thick in
the same way as in Example 1, which film was superior in both strength
and stiffness and was high in transparency. The hexane extract of the
film was 0.73%.
Example 7
830 g of anhydrous magnesium chloride, 120 g of anthracene and
170 g of titanium tetrachloride were subjected to ball milling in the same
manner as in Example 1 to give a solid substance, which contained 40 mg of
titanium per gram thereof.
Using the same apparatus as that used in Example 1, and at 80C.
there were fed the solid substance obtained above and triisobutylaluminum
at the rates of 500 mg/hr and 150 mmol/hr, respectively, and also fed were
DIALEN 610 (the trade name for an equimixture of hexene-l, octene-l and
decene-l) as comonomer, ethylene and hydrogen while making adjustment so
that the comonomer/ethylene ratio in the vapour phase was 0.14 and the
hydrogen gas pressure was 15% of the total pressure.
The polymerization was continued stably for 10 hours, then the
autoclave was opened and the reactor inside was checked to find no polymer
adhesion therein.
The polymerization activty was 143,000 g copolymer/g Ti, and the
resulting polymer had a bulk density of 0.394, MI of 2.6 and a density
of 0.909.
The polymer was formed into an inflation film, which film was
superior in both stiffness and transparency. The hexane extract of the
film was 2.6%.
Example 8
Polymerization was carried out in the same manner as in Example
7 with the proviso that the polymerization temperature, the DIALEN 610/
ethylene ratio and the hydrogen gas pressure were adjusted to 85C., 0.07
and 30% of the total pressure, respectively.
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llZ4~48
After continuous operation for 10 hours, the polymerization was
discontinued and the interior of the autocalve was checked to find it was
clean with no polymer adhesion therein.
The resulting copolymer had a bulk density of 0.395, MI of 6.4
and a density of 0.917, and the polymerization activity was 128,000
g copolymer/g Ti.
Example 9
Using the same catalyst as that used in Example 7, there was
conducted polymerization in the same manner as in Example 7 with the pro-
viso that dodecene was used in place of DIALEN 610 and the dodecene/ethy-
lene ratio and the hydrogen gas pressure were adjusted to 0.25 and 10% of
the total pressure, respectively.
The polymerization was continued for 10 hours without any trouble.
After termination of the reaction, the interior of the autoclave was
checked to find no polymer adhesion therein.
The resulting copolymer had a bulk density of 0.389, MI of 1.9
and a density of 0.881, and the polymerization activity was 110,300
g copolymer/g Ti.
The copolymer after subjected to press forming was transparent
and had a breaking point strength of 185 kg/cm2, an elongation of 700%.
Example 10
400 g of magnesium oxide and 1,300 g of anhydrous aluminum
chloride were reacted together at 300C. for 4 hours, and 950 g of the
reaction product and 170 g of titanium tetrachloride were treated in the
same way as in Example 1 to give a solid substance, which contained 3 mg
of titanium per gram thereof.
Using the same apparatus as that used in Example 1, there were
fed as catalyst the solid substance prepared above and triisobutylaluminum
at the rates of 500 mg/hr and 250 mmol/hr, respectively, and a polymeriza-
tion was made at 85C. while there were circulated a mixed gas consisting
-- 19 --
llZ49~
of ethylene and 12% thereof in the vapour phase of 4-methylpentene-1 and
hydrogen gas adjusted to 9% of the total pressure.
Af ter continuous operation for 18 hours, the reactor inside was
checked to find no polymer adhesion therein.
The resulting copolymer had a bulk density of 0.443, MI of 0.68
and a density of 0.918, composed of oval particles of a narrow particle
size distribution with an average particle diameter of 500JU. The poly-
merization activity was 179,000 g copolymer/g Ti.
The copolymer, without pelletizing, was formed into a hollow
600 cc bottle by means of a high-speed blow molding machine, which bottle
had a clean surface with no drawn-down observed.
Example ll
Polymerization was carried out in the same manner as in Example
10 with the limitation that the proportion of 4-methylpentene-1 to ethylene
was 5.5% and the hydrogen gas pressure was 30% of the total pressure.
In 10 hours, the polymerization was discontinued and the interior
of the polymerization vessel was checked to find no polymer adhesion
therein.
The resulting copolymer had a bulk density of 0.375, MI of 4.3
and a density of 0.930, and the polymerization activity was 181,000
g copolymer/g Ti.
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