Note: Descriptions are shown in the official language in which they were submitted.
~Cli763~
FIELD OF THE INVENTION:
This invention relates to a process for the polymeri-
zation of propylene, and more particularly to a process for the
manufacture of polypropylene having higher crystallinity and
improved properties by using a unique catalyst sys~em having
higher polymerization activity.
BACKGROUND OF THE INVENTION:
.
It is fundamental and well known in the production of
polypropylene to use the so-called Ziegler-Natta catalysts con-
sisting of titanium trichloride and an organoaluminum compound.In general, crystalline polymers produced by the above methods
have cxcellent mechanical, thermal, and chemical properties and
are very useful in practical applications. However, upon poly-
merization, as crystalline polymer is produced, a noticeable
amount of amorphous polymer is also formed as a by-product. The
amorphous polymer is commercially valueless and a product formed
of crystalline polymer contaminated with amorphous polymer shows
decreased physical properties. Therefore, a complicated after-
treatment is usually necessary to remo~e the amorphous polymer.
Thus, there is a great need in the production of polyolefins to
obtain a highly crystalline polymer in high yields without for-
ming a noticeable amount of amorphous polymer as a by-product. To
this end, various improvements have been proposed in the produc-
tion of titanium trichloride catalysts having higher activity.
The most common such improved catalyst is a titanium trichloride
catalyst which is prepared by reducing titanium tetrachloride
with metallic aluminum and mechanically dividing the reduced
material in a ball mill or the like.
iL~763~
Catalyst systems which can increase the crystallinity
of polyolefins are also known. In this case, a suitable third
component i5 added to the above improved type of titanium
trichloride catalyst and the organoaluminum compound. An example
of the third component is a carboxylate.
Such a catalyst system used in the manufacture of
polyolefins, however, has failed to increase the crystallinity
(stereoregularity) to sufficient levels that the removal of
amorphous polymer can be omitted. In addition the polymerization
activity remains low or may even decrease.
SV~RY OF THE INVENTION:
The present invention relates to a process for the
polymerization of propylene in the presence of a catalyst system
comprising (a) titanium trichloride, (b) an organo-aluminum
compound and (c) an organic carboxylates.
It has been found according to this invention that
the yields of polypropylene having high stereoregularity can be
improved if the titanium trichloride in the above catalyst system
is a finely granulated, purple solid obtained by precipitation
from a homogeneous liquid mixture or solution of titanium
trichloride and an ether in the presence of a Lewis acid.
Titanium trichloride used herein may be any fine-
granular solid titanium trichloride which is prepared by preci-
pitation from a homogeneous li~uid mixture or solution of titanium
trichloride and an ether. This homogeneous liquid mixture or
-- 3 --
~L~7Ç;3~1~
solution is referred to hereinafter as "the homogeneous
liquid" or "the homogeneous liquid comprising titanium
trichloride".
The precipitation is preferably carried out in
the presence of a hydrocarbon solvent and preferably at
a temperature in the range of from 20 - 150C.
The preparation of the above type of titanium
trichloride will be described in detail hereinafter. First
of all, for the preparation of a homogeneous liquid com~
prising titanium trichloride (TiC13); the following two
methods are preferred.
,;.~ , .
~L~7~30~
(A) Titanium tetrachloride is used as a starting
material, which is reduced with a particular organo-
aluminum compound in the presence of an ether and,
if desired, a suitable hydrocarbon solvent.
S (B) Solid titanium trichloride i~ used as a starting
material, which is treated with an ether, if desired,
in the presence of a suitable hydro~arbon solvent.
Method (A) will be explained. According to method (A),
titanium tetrachloride used as a starting matexial is subjected
to reduction with a particular organo-aluminum compound in the
presence of an ether and, if desired, a suitable hydrocarbon
solvent to obtain a homogeneous liquid comprising titanium
trichloride ~TiC13).
Any suitable ether may be employed as the ether in
method (A), provided it forms a homogeneous liquid with
titanium trichloride. Preferred examples of the ether
are selected from ethers which are soluble in a hydrocarbon
solvent, for example, ethers having the formula:
:RlOR;~ .............. ( 1 )
wherein Rl and R2 may be the same of different and represent
members selected from the group consisting of alkyl, aralkyl,
alkenyl, aryl and alkaryl radicals. Specific examples of the
ether include dialkyl ethers such as di-n-amyl ether, di-n-
butyl ether, di-n-propyl ether, di-n-hexyl ether, di-n-heptyl
eeher di-n-octyl ether, di-n-decyl ether, di-n-dodeoyl ether,
~ 3~
di-n-tridecyl ether, n-amyl-n-butyl ether, n-amyl isobutyl
ether, n-amyl ethyl ether, n-butyl-n-propyl ether, n-butyl
isoamyl ether, n~ethyl-n-hexyl ether, n-propyl-n-hexyl ether,
n-butyl-n-octyl ether, n-hexyl-n-octyl ether, etc.; dialkenyl
ethers such as bis(l-butenyl) ether, bis(l-octenyl) ether,
bis(l-decenyl) ether, l-octenyl-9-decenyl e~her, etc.; diaralkyl
ethers such as bis(benzyl) ether, etc.; dialXaryl ether such
as bis(tolyl) ether, bis(xylyl) ether, ~is(ethyl phenyl) ether,
tolyl xylyl ether, etc.; alkyl alkenyl ethers such as propyl-
l-butenyl ether, n-octyl-l-decenyl ether, n-decyl-l-decenyl
ether, etc.; alkyl aralkyl ethers such as n-octyl benzyl ether,
n-decyl benzyl ether, etc.; alkyl aryl ethers or alkyl alkaryl
ethers such as n-octyl phenyl ether, n-octyl tolyl ether, n-
decyl tolyl ether, etc.; aralkyl alkenyl ethers such as
l-octenyl benzyl ether, etc.; aryl alkenyl ethers or alkaryl
¦alkenyl ethers such as l-octenyl phenyl ether, l-octenyl
tolyl ether, etc~; and aralkyl aryl ethers or aralkyl alkaryl
ethers such as benzyl phenyl ether, benzyl tolyl ether, etc.
¦Among them most preferred are ethers of the formula (1)
l wherein R and R2 represent a linear hydrocarbon radical such
¦as an alkyl and alkenyl radical having more than 3 carbon atoms.
The hydrocarbon solvent which is, if necessary,
employed in method (A), is selected, mainly depending upon
the type of ether employed. Specific examples of the hydrocarbon
include to saturated aliphatic hydrocarbons such as n-pentane,
10'76300
n-hexane, n-heptane, n-octane, n-dodecane, liquid paraffin, etc.;
alicyclic hydrocarbons such as cyclohexane, methyl cyclohexane,
etc.; and axomatic hydrocarbons such as benzene, toluene,
xylene, 1,2,4-trimethyl benzene, ethyl benzene, etc. In a
¦certain case, the hydrocarbon may be selected from halohydro-
¦carbons such as chlorobenzene, bromobenzene, ortho-, meta- and
¦para-dichlorobenzene, ortho, meta- and para-dibromobenzene~
ortho- and para-chlorotaluene, 2,4-dibromotoluene, para-
bromoethyl ben~ene, l-chloronaphthalene, etc. The above-described
hydrocarbons may be used in admixture, if preferred.
Particularly when an ether having the formula ~1)
wherein at least one of Rl and R2 represents an alkyl or
alkenyl radical having less than 5 carbon atoms is used, the
hydrocarbon may preferably be an alicyclic hydrocarbon and,
most preferably, an aromatic hydrocarbon. In the case of an
ether having the formula (1) wherein Rl and R2 represent an
alkyl or alkenyl radical having more than 6 carbon atoms, the
hydrocarbon may preferably be a saturated aliphatic hydrocarbon.
A halohydrocarbon may preferably be selected when diethyl
ether is used.
For the reduction to be effected in method (A)~
an organo-aluminum compound having the general
formula:
AQRnX3 n ~ (2~
wherein R3 represents a hydrocarbon radical having 1 - 20 carbon
atoms, n is a number of the value of 1 - 3, and X represents
a halogen atom, and preferably R3 represents an alkyl radical
1~763~
having 1 - 10 carbon atoms is used~ Among these most preferred
are ethyl aluminum sesquichloride, diethyl aluminum chloride,
triethyl aluminum, tributyl aluminum, etc.
i The above-described organo-aluminum compound is used
for the reduction of titanium tetrachloride so tha~ the molar
ratio of titanium tetrachloride to the organo-aluminum compound
may be 1 : (0.1 - 50), preferably 1 : (0.3 - 10), when represented
in terms of the molar ratio of titanium to R3 constituting
the organo-aluminum compound (a hydrocarbon radical~ preferably
an alkyl radical). Further, the amount of ~he ether used
is adjusted 50 that the molar ratio of the ether to titanium
tetrachloride may be 1 : (0.05 - 5), preferably from 1 : (0.25 -
2.5).
The reduction may be effected by any of the following
different procedures.
(a) An organo-aluminum compound is added to a homogeneous
liquid consisting of titanium tetrachloride and an ether, or
vice versa.
(b) A homogeneous liquid consisting of an organo-aluminum
compound and an ether is added to titanium tetrachloride, or
vice versa.
~c) A homogeneous liquid consisting of an organo-aluminum
compound and an ether is added to a homogeneous liquid
consisting of titanium tetrachloride and an ether, or vice
versa.
(d) Titanium tetrachloride~ an ether and an organo-aluminum
compound are mixed with each other in any suitable sequence
at a temperature a-t which reduction cannot occur~ for example,
at a temperature below -30C and the mixture is then heated
to a given reduction temperature~
1076300
Titanium tetrachloride, an ether and an organo-aluminum
compound may be used either in the form of pure reagents or
in the form o reagents diluted wi~h an apropriate solvent
in the above procedures. It is particularly desired to
dilute the organo-aluminum compound with a hydrocarbon solvent.
The reduction temperature is selected from within the range
of -30 - 50C, preferably 10 - 40C.
The reduction of titanium tetrachloride with the organo-
aluminum compound in the presence of the ether according to any
of the above-described procedures results in a homogeneous
li~uid which is a homogeneous solution or mixture comprising
o titanium trichloride and the ether, besides organo-aluminum
compound and unreacted titanium tetrachloride etc. in a certain
case. This solution is soluble in the hydrocarbon solvent and
is brown or greenish brown.
It is also preferable that iodine or an iodide is
coexistent with the ether during the reduction of titanium
tetrachloride in the above-described method (A). In this
case, iodine or an iodide may preferably be added before the
reduction of titanium tetrachloride is effected~ It is also
possible to add iodine or iodide after the reduction is com-
menced, so far as the reduction has not substantially been
completed.
Method (B) will now be described. In this method,
solid titanium trichloride used as a star-ting material is
¦ treated with an ether, if desired, in the presence of an
appropriate hydrocarbon solvent to form a homogeneous liquid
I comprising titanium trichloride. As the solid titanium trichlo-
¦ ride, use may be made of, for example, a solid form of titanium
trichloride prepared by reducing titenium tetraahloride with
107~300
hydrogen gas, aluminum or an organo-aluminum compound, a
powder form of titanium trichloride prepar~d by fi~ely grinding
the above-prepared solid titanium trichloride, or another
foxm prepared by heating the above-prepared soli~ titanium
trichloride. A purified produc~ of the above solid titanium
trichloride which is obtained by removing the impurities
thererom may also be used.
Examples of the ether and the hydrocarbon solvent
used for obtaining a homogeneous liquid containing the above-
described titanium trichloride include the same compounds
as those mentioned with reference to method (A).
The ether is used in a suitable amount in method (B)
so that the mola~ ratio of the ether to titanium trichloride
may be above 1/1, preferably (1-5)/1, most pxeferably (1-2)/1.
~5 The treatment of solid titanium trichloride with
the ether may be carried out in any desired manner, preferably
by mixing them at a temperature of -30 - 120C, preferably 10 -
50C. Such a treatment is usually carried out in the presence
of a hydrocarbon solvent which is selected depending upon the
ether used as described with reference to method (A).
It is to be noted that ethers of the formula (1)
wherein Rl and R2 represent an alkyl radical having more
than 6 carbon atoms are preferably used in method (B).
A homogeneous liquid formed according to method (B)
is the same as that formed according to method (A), so far
l as the same reagents are used.
-- 10 --
1076300
As apparent from the above, either method (A) or (B)
can advantageously provide a homogeneous liquid containing
titanium trichloride.
In a subsequent step, fine-granular titanium trichloride
having a high catalytic activity to olefin polymerization i5
precipitated in the presence of a Lewis acid from the above-
prepared homogeneous liquid comprising titanium trichloride. The
precipitation is not limited to any particular method, but can be
performed according to any of widely varying methods. For example
the above-prepared homogeneous liquid as such or, if desired,
after added with the above-mentioned hydrocarbon diluent, is
heated in th~ presence of a Lewis acid to a temperature of
usually from 20 ~ 150C, preferably from 40 - 120C, most pre-
fexably from 60 - 100C to induce the precipitation, and then
lS maintained at the same temperature for a certain period of time
to ensure the precipitation until completion.
In this case, in order to facilitate the precipitation,
the amount of aforementioned hydrocarbon solvent is prefexred
to be not less than twice by weight of the ether.
In a certain case where the total mole number of titanium
and aluminum is less than the mole number of the ether in the
homogeneous liquid comprising titanium trichloride, an additional
Lewis acid may be preferably added to assist precipitation.
As the Lewis acid used for the above purpose, mention
may 'c made of Lewis acids having =tronger acidity than titanium
lll
i ' .
- ~. .
76300
trichloride, for example, organo-aluminum compounds having the
general formula:
AQRn'X3 n' ' ' (3)
wherein R4 represents an alkyl radical having 1 - 8 carbon atoms,
n' is a number of 0, 1, 1.5 or 2 and X represents a halogen
atom, titanium tetrachloride, boron tri~luoride, boron
trichloride, antimony pentachloride, gallium trichloride,
ferric trichloride, tellurium dichloride, stannic tetrachloride,
vanadium tetrachloride, thallium pentachloride, zirconium
tetrachloride, beryllium dichloride, and the corresponding
bromides and hydroxyhalides. Among them most preferred are
organo-aluminum compounds of the general formula (3) and titani~
tetrachlorideO
The amount of the Lewis acid to be added may preferably
be less than 5 moles per mole o the titanium in the homogeneous
liquid. Such an amount of the Lewis acid is added to the
homogeneous liquid before the precipitation is completed.
The precipitation may be effected in multi-steps of
different temperatures. For example, a samll portion is
precipitated at a relatively low temperature and then the
temperature is raised to cause a major portion to precipitate
in the presence of the small portion of previously precipitated
fine-granular solid titanium trichloride~ More illustratively,
first of all, the homogeneous liquid is heated to a relatively
low temperature of 20 - 70C to precipitate 1 - 50 wt% of
the total theoretical precipitation amount of finer-granular
solid purple titanium trichloride~ and then the temperature
l is raised to an elevated temperature of 45 - 150~C to precipi-
¦¦ tate the remaining portion of fine-granular solid purple
~ titanium trichloride. - 12 -
!l
Il .
., .
1076300
A seeding procedure may also be recommended with
respect to the precipitation, in which fine-granular solid
titanium txichloridel for example, having an average particle
l diameter of 0.01 - 50 ~ is previously added as seed crystals
S ¦ to the homogeneous liquid comprising titanium trichloride
before the precipitation is commenced. The kind of solid
titanium trichloride addPd as seed crystals is not particularly
restricted. Any of titanium trichloride catalysts prepared
l by the conventional methods may be employed, while fine-
¦ granular solid titanium trichloride prepared by precipitatingrom the homogeneous liquid comprising titanium trichloride
according to the above-described method is preferable. The
amount of solid titanium trichloride to be added is, for
l example, OrO05 ~ SO wt~, preferably 0.01 - 25 wt% of the
¦ theoretical amount of solid titanium trichloride precipitated.
According to the above-described method (A) or (B),
a fine-granular solid purple precipitate of titanium trichloride
is obtained. This solid titanium trichloride may either be
I directly used for polymerization or be pretreated with an
20 ¦ organo-aluminum compound, an olefin monomer such as propylene
and/or an organic carboxylate (to be described hereinafter)
according to the conventional manner before it is used for
polymerization.
I ~he component (b), or the organo-aluminum compound
of the catalyst system according to this invention includes,
I - 13 -
ll
li
1076300
by way of illustration, trialkyl aluminums such as trimethyl
aluminum, triethyl aluminum, triisobutyl aluminum, trihexyl
aluminum, etc.; and alkyl aluminum halides such as dimethyl
aluminum chloride, diethyl aluminum chloride, ethyl aluminum
chloride, diethyl aluminum bromide, ethyl aluminum sesquichlo-
ride etc. A mixture of an aluminum halide and a trialkyl aluminum
may also be employed. Among these preferred are dialkyl aluminum
halides and most pre~erred is diethyl aluminum chloride.
In addition to the above-described two components (a~
and (b), organic carboxylate is used as a third component
according to the catalyst system of ~his invention.
As the organic carhoxylate, mention may be made o~
a compound having the general formula:
R (COOR)n .............. (4)
wherein R5 and R6 represent a hydrocarbon rad~cal having 1 - 20
carbon atoms such as an alkyl, aralkyl, alkenyl, ary~, alkaryl
and alkenyl aryl radical, wherein a hydrogen atom of each
hydrocarbon radical may be replaced with an alkyl amino radical,
an amino radical, an alkyl amino radical, a nitrogen-containin~
~0 substituent such as nitro, an oxygen-containing substituent
such as alkoxy, an halogen atom or the like, and n is a number
of 1 - 3.
By way of illustration, included are methyl acetate,
ethyl acetate, propyl acetate, butyl acetate~ methyl propionate,
ethyl propionate, propyl propionate, butyl propionate, methyl
- 14 -
Il ~
107630S)
acrylate, ethyl acrylate, propyl acrylate, methyl methacrylate,
ethyl methacrylate, propyl me~hacrylate, ethyl oleate, ethyl
stearate/ e~hylphenyl acetate, methyl benzoate, e~hyl benzoate,
butyl benzoate, methyl p-toluate, propyl p-toluate, butyl
p-toluate, ethyl p-ethylbenzoate, propyl m-ethylbenzoate,
butyl o-ethylbenzoate, ethyl p-phenylbenzoate, propyl p-
phenylbenzoate, butyl p-phenylbenzoate, ethyl p-methoxybenzoate,
propyl p-methoxybenzoate, butyl p-methoxybenzoate, ethyl p-
dimethylaminobenzoate, propyl m-dimethylbenzoate, butyl p-dimethyl
benzoate, methyl cinnamate, ethyl cinnamate, e~hyl phenylacetate,
dimethyl oxalate, diethyl malonate, dimethyl terephthalate, etc.
The proportion of the above-described three components
o the catalyst system according to this invention is so selected
that the molar ratio of (a) solid titanium trichloride to (b)
the organo-aluminum compound to (c) the organic carboxylate is
usually 1 : (0.5 - 20) : (0.01 - 1), preferably 1 : (1 - 5~ :
. (0.1 - 0.2).
According to this invention, the catalyst system is
l prepared from the three components, the solid titanium trichlo-
¦ ride~ the organo-aluminum compound and the organic carboxylate~
Any suitable known method may be applied to the preparation
of this catalyst system. For example, a simple method is to
mix the above-described three components in a solvent which
l is used as a polymerization solvent in the subsequent step.
¦ The conditions with respect to temperature, atmosphere, solven~
and the like during the preparation of the catalyst system
are not particularly restricted. The same conditions as those
1076300
for polymerization are, of course, adopted when the polymeriza-
tion is carried out immediately after the catalyst is prepared.
On the other hand, it is possible to mix the three components
l at about room temperature using a partial or total amount of
¦ the solvent for polymerization when the catalyst is prepared
in advance, although conditions close to those for polymerization
are preferred.
According to the process of this invention, polymeriza-
tion of propylene or copolymerization of propylene with another
olefin is carried out using the catalyst system prepared as
above.
Examples of the olefin to be copolymerized with propy-
lene are ethylene, butene-l, 3-methyl butene-l, 4-methyl
pentene-l, pentene-l, hexene-l, etc. and mixtures thereof.
In the case of copolymerization, propylene should be
copolymerized with a small amount of an olefin other than
propylene so that the resulting copolymer may not lose the
properties inherent to polypropylene. The amount of an olefin
other than propylene may be in the range of 0.1 - 10 ~ by
weight, preferably 1 - 8 ~ by weight based on the total amount
of the resulting propylene copolymer
This kind of polymerization of propylene is usually
conducted in an aliphatic hydrocarbon solvent such as hexane,
heptane, cyclohexane, pentane, butane and propane, while the
polymerization may preferably be conducted without any solvent
~bulk polymerization) in a certain case. Furthermorel the process
; ¦ of this invention may also be applied to vapor phase polymeriza-
tion.
- 16 -
I!
1076300
Polymerization conditions may vary within very wide
ranges. Though the polymerization can be conduc~ed at a pressure
below atmospheric pressure, a pressure in the range of 1 - 150
atm, preferably 5 - 30 atm is selected in order to obtain a
S commercially` advantageous rate of polymerization. The polymeriza-
tion temperature is usually selected in the range of 40 - 100C.
preferably 50 - 70C.
The polymerization may be carried out in either a
batchwise or a continuous manner. It is also contemplated to
modify the molecular weigh~ o~ a polymer obtained. To this
end, a suitable amount of a known molecular weight modifier such
as hydrogen and diethyl zinc may be added to the polymerization
system.
According to the above-described manner, polypropylene
is certainly obtained~ The process of this invention has
the following advantages.
(1) A polymer product obtained according to this invention is
highly crystalline and contains only a small or negligible
amount of an amorphous polymer which is substantially valueless
in industry.
(2) The amorphous polymer contained in the powdery polymer
product according to this invention has unique solubility in a
hydrocarbon solvent which decreases at a higher rate as the
temperature falls than that of amorphous polymers obtained by
1 the conventional process. Therefore, the behaviox of a slurry
l during polymerization and after-treatment is very good and the
1~6300
operating stability is also very high when compared with the
conventional process.
~3) The polymer insoluble in the hydrocarbon solvent has a
remarkably higher bulk density than those obtained by the
S conventional process. This also causes an improvement in the
behaviour of the slurry.
(4) The polymer obtained according to this invention, parti-
cularly the polymer product containing the amorphous polymer
which is insoluble in the hydrocarbon solvent at temperatures
near the polymerization or after-treatment temperature~ shows
more improved product characteris~ics than the conventional
polymers. Therefore, the polymer obtained according to this
invention can be directly formed into products such as ~ilms,
tapes, flat yarns, molded articles or the like without removing
the amorphous polymer. This act in combination with the
reduced solubility of the amorphous polymer in the hydrocarbon
solvent contxibutes ~o an improvement in rate of conversion of
a charge monomer to a useful polymer.
The following examples illustrate ~he invention. They
are set forth as a further description, but are not to ~e con~t-
rued as limiting the invention thereto. In the examples and
comparative examples, the abbreviations s~and for the ollowing
mean~ngs.
i) K : polymerization ac~ivity repre~ented in ~erms of the
amount (g) of polypropylene produced per gram of the
catalyst-constituting titani~m trichloride component
per hour at an olefin-charge pressure of 1 ky/cm2.
1~)~6300
ii) CE : catalytic eficiency represented in terms of the
amount (g) of polypropylene produced per gxam of the
catalyst-constituting titanium trichloride component.
iii)I.I. : isotactic index represen~ed in terms of the amount
(wt~) of the polymer remained after a 6-hour
extraction with boiling n-heptane in a modified-
type Soxhlet apparatus. Since the amorphous polymer
which causes physical properties to decrease is
soluble in boiling n-heptane, I.I. shows the yield
of the crystalline polymer.
iv) Pg : bulk density (g/cc) measured according to JIS 6721.
v) MFI : melt flow index (g/lO min.~ measured according to
ASTM D-12380
¦ vi) YS : strength at primary yield point (kg/cm2) measured
¦ according to ASTM D-412.
¦ vii)TI : tensile impact strength (kg-cm/cm2) measured accord~
¦ ing to ASTM D-1822.
Examples l - 5:
Pre aration of titanium trichloride
P _ _
A l-liter four-necked flask is charged with 0.3 Q
of n-heptane, 180 mmols of titanium tetrachloride and 180 mmols
of n-octyl ether. With stirring at room temperature, 60 mmols
of diethyl aluminum chloride is added dropwise in the flas]c,
obtaining a homogeneous brown solutionO With further stirring,
this solution is heated up to 90C, while a purple precipitate
-- 1 9
107630l~
of titanium trichloride is observed in the course of heating.
The solution is stirred for 1 hour at 90~CO The resulting
precipitate is separated by decantation from the mother li~uor
¦ and then washed with n-heptane (from which oxygen and water
S ¦ have been removed). The X-ray diffraction of this purple pre-
¦ cipitate shows that the precipitate mainly consists o~ ~-type
¦ titanium trichloride. Aluminum is under the sensible level
¦ and 15 wt% of octyl ether is contained.
I B. Polymerization o~ Propylene
I
¦ A 2-li~er induction rotary ~ype autoclave which has
been purged and filled with propylene gas is charged with 1 Q
of n-hexane ~rom which oxygen and water have been removed).
Thereater, a given amount of ~he purple precipitate (titanium
trichloride catalyst) prepared in the abov~, diethyl aluminum
monochloride in an amount to give an atomic ratio o Al/Ti of
¦ 4, and a given amount of a carboxylate are added in this order.
¦ After hydrogen gas is foxcedly introduced to a partial pressure
¦ of 0.5 kg/cm2, the autoclave is heated to 60C. Stirring is
¦ performed and thereafter propylene gas is fed from a feed pipe
¦ to a partial pressure of 20 kg/cm . ~hile maintaining this
¦ partial pxessure of 20 kg/cm2, polymerization is continued for
¦ 5 hours. Ater the reaction, the unreacted propylene gas is
¦ purged and the contents including n-hexane are taken out from
¦ the autoclave. The liquid phase is evaporated and the residue
¦ is dried. The resulting polypropylene powder including the
smorphous polymer is weighed. Thereafter, the polypropy1ene
~ 20
I
!l
107t;300
product is washed 3 ~imes with methanol containing 2 % of hydro-
chloric acid at its boiling point for 3 hours. The amorphous
polymer is not removed. The conditions for polymerization and
the results are shown in Table 1.
comparative Example 1:
Following the procedure (B) of Example 1, polymeriza-
¦ tion is carried out, except that the amount of the titanium
¦ trichloride catalyst used is changed and no carboxylate is
¦ added. The results are shown in Table 1.
¦ Comparative Example 2:
Polymerization is conducted in the same manner as
described in Example l-B, except that a given amount of a
commercially available catalyst C-141, TiC13 1/3 AlC13) is
used instead of the titanium trichloride catalys~ prepared
according to the invention. A given amount of ethyl benzoate
¦ is used as the carboxyate. The results are shown
¦ in Table 1.
¦ The results of Comparative Example 1 are also shown
¦ in Table 1 as an example in which polymerization is conducted
¦ in the same manner as described in Example l-B, except that
the titanium trichloride catalyst is used in a different amount
and the carboxylate is not used.
-- 21 --
Il .
1076300
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1076300
Reference Example:
The polypropylene products in;-luding all the amorphous
polymer obtained in Examples 1, 2 and 5 and Comparative Examples
1 and 2 are washed 3 times with n-heptane containing 5 % of 1-
propanol at 70C for 3 hours to remove a part of the amorphous
polymer. The resulting polypropylene is tested for various
mechanical properties, the results are shown in Table 2.
Table 2
l Amorphous polymer Mechanical properties
l I.I. MFI YS TI
¦ Example 1 included 94.4 4.9 349 65
removed 97.0 4.8 351 65
¦ Example 2 included 95.2 6.3 346 60
I removed 97.9 6.4 350 59
¦ Example 5 included 95.7 5.7 340 73
¦ removed 98.1 5~8 348 72
1 Comparative included 88.6 5.8 30.3 58
Example 1 removed 90.3 5.8 305 58
Comparative included 93.3 6.1 321 53
Example 2 removed 94.3 6.2 330 52
It is obvious from Table 2 that the products of
~0 ¦ Examples according to the invention show more excellent mecha-
nical properties than those of Comparative Examples, irrespective
of the removal of the amorphous polymer. This means that
polypropylene products obtained according to the invention can
l be practically applied without removing the amorphous polymer
formed as a by-product.
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~ 1076300
Example 6: ¦
Polymerization is conducted in the same manner as
described in Example l-B, except that titanium trichloride is
47.9 mg and ethyl p-methoxybenzoa~e as a carboxylate is added so
S as to give a molar ratio of the ester ~o titanium trichloride
of 0.17. There is obtained 541 g of a polypropylene powder.
CE K II PB MFI YS TI
11,300 m ~ o. ~4 5.2 3S7 68
Examples 7 - 10:
~olymerization is conducted in the same manner as
described in Example 1-~, except that the amount of the titanium
trichloride catalyst is ~aried and carboxylate prepared in the
following manner is used. The results are shown in Table 3~
As the carboxylate, a product obtained by reacting a
lS carboxylate with diethyl aluminum monochloride (DEA) is used.
To this end, the carboxylate is firs~ dissolved in heptane or
toluene to obtain a 0.25 mmol/ml solution. With stirring in argon
atmospherey DEA is added dropwise to the solution at room tempera-
tùre, the molar amount of DEA being equal to that of the carboxy-
late. After the addition, the mixture is heated at 60C for 1
hour and then cooled, which product is ready for use in polymeri-
za~ion.
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