Process for preparing ethylenic polymer composition

A process for the preparation of an ethylenic polymer composition having excellent physical properties such as high impact properties, environmental stress cracking resistance, pinch-off fusing characteristics and having an intrinsic viscosity ranging from 3.2 to 4.5 dl/g and a density ranging from 0.943 g/cm.sup.3 to 0.958 g/cm.sup.3.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The present invention relates to a process for preparing an ethylenic 
polymer composition and, more particularly, to a process for preparing an 
ethylenic composition having excellent physical properties such as high 
impact properties, environmental stress cracking resistance (ESCR), 
pinch-off fusing characteristics, and so on. 
2. Description of Related Art 
As a process for preparing blow-molding polyethylene having a wide range of 
molecular weight distribution, is there a known two-stage polymerization 
method. Polyethylene prepared by the two-stage polymerization method are 
excellent in a balance between toughness and environmental stress cracking 
resistance (ESCR), compared with polyethylene prepared by one-stage 
polymerization method, however, the former has the drawbacks that a 
tolerance for a pinch-off shape of the mold is narrow because a fusing 
strength of the pinch-off portion of a hollow molding is small, and a 
ratio of defective products is high and that die swell is small. 
In order to improve the drawbacks of the conventional two-stage 
polymerization method, Japanese Patent Examined Publication No. 
10,724/1984 proposes a three-stage polymerization method. This three-stage 
polymerization method can improve the die swell for the resulting 
polyethylene to a sufficient extent, however, improvements in the 
pinch-off fusing characteristics are not sufficient yet. Further, the 
three-stage polymerization method presents the disadvantages that it uses 
three reaction vessels so that control of polymerization is so complicated 
and costs of equipment become expensive. 
Japanese Patent Unexamined Publication No. 85,690/1985 and Japanese Patent 
Examined Publication No. 27,677/1987 propose processes for preparing 
alpha-olefin polymers using one polymerization vessel in the presence of a 
catalyst obtainable from an organometallic compound, a magnesium compound, 
a titanium compound and an aluminium compound. 
As a result of comparative studies, it has been found that this 
polymerization process is difficult to provide a polymer having physical 
properties required for blow molding, such as high impact properties, 
ESCR, pinch-off fusing characteristics, and so on. 
SUMMARY OF THE INVENTION 
Therefore, the present invention has been performed under the circumstances 
as described hereinabove and has the object to provide a process for 
preparing an ethylenic polymer composition which is excellent in high 
impact properties, ESCR, pinch-off fusing characteristics and so on, as 
compared with the polyethylene prepared by the conventional one-stage 
polymerization method, and which is excellent particularly in pinch-off 
fusing characteristics, as compared with the polyethylene prepared by the 
three-stage polymerization method, and which can solve the problems of the 
two-stage polymerization method, such as a complicated operation for 
preparing the catalyst to be used therefor, a low activity per one 
transition metal, and a large amount of the metals left in the resulting 
polymer. 
The present invention provides a process for preparing the ethylenic 
polymer composition with high productivity, which has physical properties 
suitable for hollow molding, in particularly excellent pinch-off fusing 
properties, die swell and appearance as well as high mechanical 
characteristics and ESCR, in a well balanced fashion, and which can be 
molded at high speeds. 
In order to achieve the object, the present invention consists of a process 
for preparing an ethylenic polymer composition comprising a combination in 
any order of: 
step (a) for preparing an ethylene homopolymer or copolymer at a rate 
ranging from 1 to 23% by weight with respect to the total polymerization 
amount at a temperature of 30.degree. C. to 80.degree. C., said ethylenic 
polymer or copolymer containing an alpha-olefin other than ethylene in an 
amount of 10% by weight or lower and having an intrinsic viscosity [.eta.] 
of 10 dl/g to 40 dl/g; and 
step (b) for preparing an ethylene homopolymer or copolymer at a rate 
ranging from 77 to 99% by weight with respect to the total polymerization 
amount at a temperature of 60.degree. C. to 100.degree. C., said ethylenic 
polymer or copolymer containing an alpha-olefin other than ethylene in an 
amount of 10% by weight or lower and having an intrinsic viscosity [.eta.] 
of 1.0 dl/g to 5.0 dl/g; in the presence of a catalyst obtainable from a 
solid catalyst component selected from a group consisting of a solid 
catalyst component obtainable from a magnesium alkoxide, a titanium 
compound and an organoaluminium halide, and a solid catalyst component 
containing at least titanium, zirconium, magnesium and a halogen, and an 
organoaluminium compound.

DESCRIPTION OF THE PREFERRED EMBODIMENTS 
The process according to the present invention basically involves a 
particular two-step polymerization in preparing the ethylenic polymer 
composition by copolymerizing ethylene with an alpha-olefin other than 
ethylene in the presence of the catalyst obtainable from the solid 
catalyst component and the organoaluminium compound. 
I. Catalyst 
The catalyst to be used for the process according to the present invention 
may include: 
(I) a catalyst obtainable from the solid catalyst component obtainable from 
the magnesium alkoxide, the titanium compound and the organoaluminium 
halide and the organoaluminium compound; and 
(II) a catalyst obtainable from the solid catalyst component containing at 
least titanium, zirconium, magnesium and the halogen and the 
organoaluminium compound. 
Catalyst (I) 
(1) Solid Catalyst Component 
The solid catalyst component for the catalyst (I) may contain the magnesium 
alkoxide, the titanium compound and the organoaluminium halide. 
(i) Magnesium alkoxide 
The magnesium alkoxide to be used for the solid catalyst component may be 
represented by the following general formula [2]: 
EQU Mg(OR.sup.1).sub.z X.sub.2-a [ 1] 
(wherein R.sup.1 is a linear or branched alkyl, cycloalkyl, aryl or aralkyl 
group, each having from 1 to 10 carbon atoms; 
X is a halogen atom such as fluorine, chlorine, bromine and so on; and 
a is a real number ranging from 1 to 2). 
The magnesium alkoxide as represented by the general formula [1] may 
include, for example, an alkoxymagnesium halide, such as methoxymagnesium 
chloride, ethoxymagnesium chloride, ethoxymagnesium bromide, 
ethoxymagnesium iodide, propoxymagnesium chloride, isopropoxymagnesium 
chloride, butoxymagnesium chloride, sec-butoxymagnesium chloride, 
isobutoxymagnesium chloride, tert-butoxymagnesium chloride, 
pentyloxymagnesium chloride and hexyloxymagnesium chloride, a 
dialkoxymagnesium, such as dimethoxymagnesium, diethoxymagnesium, 
dipropoxymagneslum, diisopropoxymagnesium and dibutoxymagnesium, a 
diarylmagnesium, such as diphenoxymagnesium, a diaryloxymagnesium, such as 
dibenzyloxymagnesium, an alkoxyphenoxymagnesium, such as 
ethoxyphenoxymagnesium and butoxyphenoxymagnesium, and so on. 
These magnesium alkoxides may be used singly or in combination of two or 
more. 
Among the magnesium alkoxides, a magnesium alkoxide having a lower alkoxy 
group is preferred, and magnesium dimethoxide or magnesium diethoxide is 
preferred. 
(ii) Titanium compound 
The titanium compound to be used for the solid catalyst component may be 
represented by the following general formula [2]: 
EQU M(OR.sup.2).sub.n X.sub.4-n [ 2] 
(wherein R is an alkyl, cycloalkyl, aryl or aralkyl group, each having from 
1 to 20 carbon atoms; 
M is a titanium atom; 
X has the same meaning as above; and 
n is defined by: 0.ltoreq.n.ltoreq.4). 
Representatives of the titanium compounds as represented by the general 
formula [2] above may include: titanium tetrachloride and titanium 
tetrabromide, when n is 0; ethoxytrichlorotitanium, 
n-propoxytrichlorotitanium and n-butoxytrichlorotitanium, when n is 1; 
diethoxydichlorotitanium, di-n-propoxydichlorotitanium and 
di-n-butoxydichlorotitanium, when n is 2; triethoxymonochlorotitanium, 
tri-n-propoxymonochlorotitanium and tri-n-butoxymonochlorotitanium, when n 
is 3; and tetraethoxytitanium, tetra-n-propoxytitanium and 
tetra-n-butoxytitanium, when n is 4. 
These titanium compounds may be used singly or in combination of two or 
more. 
Among the titanium compounds, a alkoxytitanium having a lower alkoxy group 
is preferred, and tetra-n-butoxytitanium is preferred. 
(iii) Organoaluminium halide: 
The organoaluminium halide may include, for example, dimethylaluminium 
monochloride, diethylaluminium monochloride, diisopropylaluminium 
monochloride, diisobutylaluminium monochloride, methylaluminium 
dichloride, ethylaluminium dichloride, isopropylaluminium dichloride and 
isobutylaluminium dichloride. 
The organoaluminium halide may be used singly or in combination of two or 
more. 
Among the organoaluminium halides, a lower alkylaluminium halide is 
preferred, and ethylaluminium dichloride is more preferred. 
(iv) Preparation of solid catalyst component 
The solid catalyst component may be prepared by contacting the magnesium 
alkoxide, the titanium compound and the organoaluminium halide with each 
other. 
In preparing the solid catalyst component, it is preferred that a molar 
ratio of the organoaluminium halide to the titanium compound may range 
from 1:1 to 100:1, preferably from 3:1 to 40:1 and that a molar ratio of 
the magnesium alkoxide to the titanium compound may range from 1:1 to 
100:1, preferably from 2:1 to 40:1. 
Although the order of contacting the components is not limited to a 
particular one, it is preferred that the magnesium alkoxide is first 
contacted with the titanium compound and then the resulting mixture is 
contacted with the organoaluminiumhalide. 
They are contacted with each other usually in an inert solvent- The inert 
solvent may preferably include one or more of a hydrocarbon solvent 
selected from pentane, hexane, cyclohexane, heptane and so on. 
It is preferred that the organoaluminium halide is gradually added so as to 
allow the reaction to proceed uniformly while keeping the temperature of 
the system at 10.degree. C. to 50.degree. C. 
(2) Organoaluminium Compound 
The resulting solid catalyst component is then contacted with the 
organoaluminium compound, thereby yielding the catalyst to be used for the 
polymerization. 
The organoaluminium compound may include, for example, trimethylaluminium, 
triethylaluminium, triisopropylaluminium, triisobutylaluminium, 
diethylaluminium monochloride, diisopropylaluminium monochloride, 
diisobutylaluminiummonochloride, dioctylaluminium monochloride, 
ethylaluminium dichloride, diethylaluminium monoethoxide, 
isopropylaluminium dichloride, ethylaluminium sesquichloride and so on. 
(3) Preparation of Catalyst 
The catalyst to be used for the process according to the present invention 
may be prepared by contacting the solid catalyst component with the 
organoaluminium compound in conventional manner. 
In preparing the catalyst, it is preferred to adjust an atomic ratio of the 
aluminium atom to the titanium atom in the solid catalyst component in the 
range usually from 1:1 to 1,000:1, preferably from 10:1 to 200:1. 
It is further preferred to use a polymerization catalyst having an activity 
of 50 kg-PE/g.Ti or larger, preferably 100 kg-PE/g.Ti or larger. 
Catalyst (II) 
As the catalyst to be used for the polymerization, there may be used a 
binary-type transition metal catalyst containing Ti and Zr. More 
specifically, there may be used Ziegler-type catalysts, for example, as 
disclosed in Japanese Patent Unexamined Publication Nos. 12,006/1982 and 
12,007/1982 or in Japanese Patent Application No. 137,712/1987. 
Such catalysts may include: 
(a) a catalyst containing a solid product (A1), as an effective ingredient, 
which may be obtainable by reacting a compound containing at least 
titanium, magnesium and a halogen with a tetraalkoxyzirconium and/or a 
zirconium tetrahalide and then reacting the resulting solid material with 
a halogen-containing titanium compound which may contain an alkoxy group, 
and the organoaluminium compound (B) as an effective ingredient; 
(b) a catalyst containing a solid product (A2), as an effective ingredient, 
which may be obtainable by reacting a compound containing at least 
titanium, magnesium and a halogen with a tetraalkoxyzirconium and then 
reacting the resulting solid material with the organoaluminium halide, and 
the organoaluminium compound (B) as an effective ingredient; and 
(c) a catalyst consisting of a solid catalyst component (A3) prepared by 
contacting a mixture of a magnesium dialkoxide and a titanium 
tetraalkoxide with an alkanol such as isopropanol or the like to thereby 
yield a magnesium-containing composite which in turn is reacted with a 
tetraalkoxyzirconium or a zirconium tetrahalide or both and then by 
reacting the resulting reaction mixture with the organoaluminium halide 
and (B) the organoaluminium compound. 
For these catalysts, it is noted that the molar ratio of Zr to Ti 
preferably ranges from 0.5:1 to 20:1. 
As the compound containing at least titanium, magnesium and halogen, there 
may be enumerated, for example, a solid substance obtainable by reacting 
an inorganic magnesium compound such as magnesium oxide, magnesium 
hydroxide, magnesium carbonate, magnesium sulfate, a magnesium halide or 
the like with a titanium halide, a solid substance obtainable by reacting 
a variety of magnesium compounds with a silicon halide, an alcohol and a 
titanium halide in order, or a solid substance obtainable by reacting a 
dialkoxymagnesium such as magnesium diethoxide with magnesium sulfate and 
a titanium halide. 
Furthermore, as the compound containing at least titanium, magnesium and 
halogen, there may also be used a solid substance obtainable by reacting 
an inorganic compound containing a Mg-O bond, such as magnesium oxide, 
magnesium hydroxide, magnesium carbonate or the like, with magnesium 
sulfate, a silicon halide and an alcohol in this order and then reacting 
the resulting precipitate with a silicon halide or an organosilicon 
compound, such as SiCl.sub.4, CH.sub.3 OSiCl.sub.3, (CH.sub.3 O).sub.2 
SiCl.sub.2, (CH.sub.3 O).sub.3 SiCl, Si(OCH.sub.3).sub.4, C.sub.2 H.sub.5 
OSiCl.sub.3, (C.sub.2 H.sub.5 O).sub.2 SiCl.sub.2, (Cl.sub.2 H.sub.5 
O).sub.3 -SiCl.sub.2, Si(OC.sub.2 H.sub.5).sub.4 and so on. There may also 
be used a solid substance obtainable by reacting a dialkoxymagnesium with 
an alcohol-adduct of a magnesium halide such as MgCl.sub.2 
.multidot.6C.sub.2 H.sub.5 OH and reacting the resulting product produced 
by treatment with an alcohol with the titanium halide. 
As the halogen-containing titanium compound which may contain the alkoxy 
group, there may be exemplified TiCl.sub.4, TiBr.sub.4, 
Ti(OCH.sub.3)Cl.sub.3, Ti(OC.sub.2 H.sub.5).sub.2 Cl.sub.2, Ti(OC.sub.2 
H.sub.5).sub.3 Cl, and so on. 
The organoaluminium compound may include, for example, trimethylaluminium, 
triethylaluminium, triisopropylaluminium, triisobutylaluminium, 
diethylaluminium monochloride, diisopropylaluminiummonochloride, 
diisobutylaluminium monochloride, dioctylaluminium monochloride, 
ethylalnminium dichloride, diethylaluminium monoethoxide, 
isopropylaluminium dichloride, ethylaluminium sesquichloride and so on. 
The organoaluminium halide may include, for example, dimethylaluminium 
monochloride, diethylaluminium monochloride, diisopropylaluminium 
monochloride, diisobutylaluminium monochloride, methylaluminium 
dichloride, ethylaluminium dichloride, isopropylaluminium dichloride and 
isobutylaluminium dichloride. 
The titanium tetraalkoxide or zirconium alkoxide may be represented by the 
following general formula [3]: 
EQU M(OR.sup.3).sub.4 
(where R.sup.3 is an alkyl group, a cycloalkyl group, an aryl group or an 
aralkyl group, each having from 1 to 20 carbon atoms; and 
M is titanium or zirconium). 
The compound as represented by the general formula [3] may include, for 
example, tetraethoxytitanium, tetra(n-propoxy)titanium, 
tetra(n-butoxy)titanium, tetra(n-pentoxy)titanium, 
tetra(n-hexoxy)titaninm, tetra(n-heptoxy)titanium, 
tetra(n-octoxy)titanium, tetracyclopentoxytitanium, 
tetracyclohexoxytitanium, tetracycloheptoxytitanium, 
tetracyclooctoxytitanium, tetraphenoxytitanium and the zirconium compounds 
corresponding to the titanium compounds. 
The catalyst (II) to be used for the present invention may be prepared by 
preparing the solid catalyst component using each of the ingredients as 
described hereinabove in conventional manner to thereby yield the solid 
catalyst component and contacting the solid catalyst component with the 
organoaluminium compound in conventional marker. 
II. Polymerization 
In accordance with the present invention, polymerization may be carried out 
using the catalyst as prepared hereinabove. 
The process according to the present invention comprises polymerizing 
ethylene or copolymerizing ethylene with the alpha-olefin other than 
ethylene in two steps, one step involving a polymerization step for 
preparing a polymer having a higher molecular weight and the other step 
involving a polymerization step for preparing a polymer having a lower 
molecular weight. 
As will be described in more detail hereinafter, the step (a) is a step for 
preparing the polymer having a higher molecular weight and the step (b) is 
a step for preparing the polymer having a lower molecular weight. Either 
of the step (a) or step (b) may first be carried out before the other. 
Step (a) 
The polymerization in the step (a) may be carried out at temperatures 
ranging from 30.degree. C. to 80.degree. C. If the polymerization 
temperature is too low, productivity may become too low. If the 
temperature is too high, it may be difficult to adjust the intrinsic 
viscosity [.eta.]. 
In the step (a), an ethylene homopolymer or an ethylene copolymer with the 
alpha-olefin other than ethylene [hereinafter referred to as component 
(A)] may be prepared such that it contains the alpha-olefin other than 
ethylene in an amount of 10% by weight or lower, preferably 5% by weight 
or lower, it has an intrinsic viscosity [.eta.] ranging from 10 dl/g to 40 
dl/g, preferably from 15 dl/g to 30 dl/g, and it accounts for 1% to 23% by 
weight, preferably from 3% to 20% by weight, with respect to the total 
amount of polymerization. 
When the content of the alpha-olefin other than ethylene exceeds the upper 
limit, an amount of ingredients soluble in the solvent may increase and 
toughness of the resulting ethylenic polymer composition also may 
decrease. Furthermore, too much of the alpha-olefin other than ethylene 
may make a continuous operation for a long period of time difficult. 
The intrinsic viscosity [.eta.] below the lower limit may worsen the 
pinch-off fusing characteristics and the flowability of the resulting 
ethylenic polymer composition while the intrinsic viscosity [.eta.] above 
the upper limit may reduce the high-impact properties and cause a large 
number of fish eyes on the resulting products. 
As the alpha-olefin other than ethylene, there may be exemplified an 
alpha-olefin having from 3 to 10 carbon atoms, preferably from 3 to 8 
carbon atoms, which may specifically include, for example, propylene, 
butene-1, hexene-1, octene-1 and so on. 
As described hereinabove, the component (A) may be prepared in the step (a) 
at the rate which accounts for 1% to 23% by weight with respect to the 
total amount of polymerization. When this rate becomes too low, the 
pinch-off fusing properties and compatibility may be worsened. A too high 
rate of the component (A) may impair the properties for hollow molding. 
Step (b) 
The polymerization in the step (b) may be carried out at temperatures 
ranging from 60.degree. C. to 100.degree. C. If the polymerization 
temperature is too low, productivity may become too low. If the 
temperature is too high, a portion of the resulting polymer may be caused 
to be aggregated, thereby making it difficult to perform a continuous 
operation. 
In the step (b), the ethylene homopolymer or the ethylene copolymer with 
the alpha-olefin other than ethylene [hereinafter referred to as component 
(B)] may be prepared such that it contains the alpha-olefin other than 
ethylene in an amount of 10% by weight or lower, preferably 3% by weight 
or lower, it has an intrinsic viscosity [.eta.] ranging from 1.0 dl/g to 
5.0 dl/g, preferably from 1.5 dl/g to 4.0 dl/g, and it accounts for 77% to 
99% by weight with respect to the total amount of polymerization. 
When the content of the alpha-olefin other than ethylene exceeds the upper 
limit, an amount of ingredients soluble in the solvent may increase, 
thereby worsening a balance between toughness and ESCR of the resulting 
ethylenic polymer composition. The intrinsic viscosity [.eta.] below the 
lower limit may increase an amount of ingredients soluble in the solvent, 
while the intrinsic viscosity [.eta.] above the upper limit may reduce 
flowability of the resulting ethylenic polymer composition. 
As the alpha-olefin other than ethylene, there may be used the same one as 
used in the step (a) or one different from those as enumerated for the 
step (a), although use of the same kind is preferred. 
As described hereinabove, the component (B) may be prepared in the step (b) 
at the rate which accounts for from 77% to 99% by weight, preferably from 
80% to 97% by weight, with respect to the total amount of polymerization. 
In the process according to the present invention, it is possible to change 
a balance between toughness and ESCR for the resulting ethylenic polymer 
composition by changing the content of the alpha-olefin other than 
ethylene. It may be noted that the ethylene homopolymer or copolymer 
having a better toughness can be obtained when no alpha-olefin other than 
ethylene is used in either of the step (a) or step (b), on the one hand, 
while the ethylene copolymer having a better ESCR can be obtained when the 
alpha-olefin other than ethylene is used in both step (a) and step (b), on 
the other hand. 
Each of the steps (a) and (b) may be carried out by any polymerization, 
such as suspension polymerization, solution polymerization and gas phase 
polymerization, in a continuous or batch manner. In both steps (a) and 
(b), a solvent such as pentane, n-hexane, cyclohexane, heptane, benzene or 
toluene may be used. 
III. Ethylenic Polymer Composition 
The process according to the present invention may provide the ethylenic 
polymer composition having an intrinsic viscosity [.eta.] ranging usually 
from 3.0 dl/g to 5.0 dl/g, preferably from 3.2 dl/g to 4.5 dl/g, a density 
ranging from 0.940 g/cm.sup.3 to 0.961 g/cm.sup.3, preferably from 0.943 
g/cm.sup.3 to 0.958 g/cm.sup.3, more preferably from 0.950 g/cm.sup.3 to 
0.953 g/cm.sup.3, and a melt index ranging from 0.01 to 0.08 g/10 minutes. 
The ethylenic polymer composition having an intrinsic viscosity below the 
lower limit has its ESCR reduced and its hollow moldability worsened and 
causes a number of fish eyes, on the one hand, and the ethylenic polymer 
composition having an intrinsic viscosity above the upper limit is poor in 
hollow molding at high speeds, on the other hand. If the density is below 
the lower limit, toughness of the resulting composition may become too 
small and, if the density is above the upper limit, ESCR may be reduced. 
The ethylenic polymer composition prepared by the process according to the 
present invention has two peaks of a molecular weight distribution, one 
peak for a polymer having a higher molecular weight and the other for a 
polymer having a lower molecular weight. 
The ethylenic polymer composition thus prepared is excellent in large blow 
molding, great in pinch-off fusing characteristics and die swell, 
remarkable in appearance, and large in flowability, so that it has an 
excellent moldability at high speeds. It also has a greater melt tension 
so that a cut of a parison can be prevented. Furthermore, the ethylenic 
polymer composition and moldings formed therefrom have a good balance 
between high ESCR and high toughness and they are excellent in high-impact 
properties. 
It is further to be noted that the ethylenic polymer composition prepared 
by the process according to the present invention are also excellent as a 
material for inflation molding as well as for large-scale blow molding and 
as a material for covering steel pipes. 
Furthermore, it is noted that the process according to the present 
invention can continuously prepare the ethylenic polymer composition with 
high efficiency, which is excellent in hollow molding, particularly in 
moldability at high speeds due to its large pinch-off fusing properties, 
large die swell, good appearance and flowability. 
EXAMPLES 
The present invention will be described in more detail by way of examples. 
It is noted that the polymers prepared in examples and comparative examples 
are measured for their properties in the following way: 
(1) Intrinsic viscosity: Measured at 135.degree. C. in decalin. 
(2) Density: JIS-K 7112 
(3) ESCR: ASTM D-1693; temperature, 50.degree. C.; surfactant ("NISSAN 
NONION" 10% aqueous solution; F.sub.50 value) 
(4) Tensile modulus: JIS-K 6760; temperature, 23.degree. C. 
(5) Melt tension: Melt tension meter (Toyo Seiki K.K.); orifice: D=2.10 mm, 
L=8.00 mm; temperature: 190.degree. C.; falling velocity of plunger: 15 
mm/minute; velocity of pulling thread: 10 rpm 
(6) Izod impact strength: ASTM D-256; notched; temperature: 23.degree. C. 
(7) Moldability: Molding machine: 10-liter accumulator with a die having a 
diameter of 90mm (manufactured by IHI); setting temperatures: C1, 
180.degree. C.; C2, 190.degree. C.; C3, 200.degree. C.; adapter, 
220.degree. C.; CH1, 220.degree. C.; CH2, 220.degree. C.; die, 220.degree. 
C.; molding cycle, 5 minutes; load, 5 kg; Molded into a vessel which in 
turn is measured for its pinch-off thickness and thickness of its convex 
portion as follows: 
(i) Pinch-off thickness: A central portion of the pinch-off portion of the 
vessel bottom was cut out at a right angle to the pinch-off portion and 
the minimum thickness of the pinch-off portion was measured with a slide 
gauge. 
(ii) Convex thickness: A portion of the upper portion of the vessel close 
to the convex portion of a mold was cut out at a right angle to the 
pinch-off portion and its minimum thickness was measured with a slide 
gauge. 
Example 1 
(1) Preparation of solid catalyst component 
A solution of 200 grams (0.6 mole) of tetra-n-butoxytitanium in 5 liters of 
hexane was added at 20.degree. C. to 7 liters of a hexane slurry 
containing 890 grams (7.8 mole) of diethoxymagnesium. To this mixture, 9.4 
liters of a 50% by weight hexane solution of ethylaluminium dichloride, 
while warming to 40.degree. C. with stirring, were added over the period 
of 60 minutes, and the resulting mixture was reacted further for 120 
minutes under reflux conditions. The resulting reaction mixture was washed 
well with dry hexane until no chlorine could be detected any more. 
Thereafter, the total volume was made 30 liters. 
(2) Preparation of ethylenic polymer composition 
A 200-liter polymerization reactor of the first stage was continuously 
charged with ethylene at the rate of 9 kg per hour, hexane at the rate of 
26 liters per hour, butene-1 at the rate of 72 grams per hour and hydrogen 
so as to produce a polymer having the intrinsic viscosity as shown in 
Table 1 below. Furthermore, the reactor was then charged with the 
catalyst, prepared hereinabove, at the rate of 0.6 millimole per hour, 
when converted into Ti, and triisobutylaluminium at the rate of 18 
millimole per hour. The mixture was subjected to polymerization at 
80.degree. C. and a residence time of 3 hours. The content of the first 
stage reactor was then transferred continuously at a given speed to a 
hydrogen-deaerating vessel. 
After deaeration of hydrogen, the reaction mixture was then transferred to 
a 200-liter polymerization reactor of the second stage which in turn was 
continuously charged with ethylene at the rate of 1 kg per hour and hexane 
at the rate of 3 liters per hour. The mixture was then subjected to 
polymerization at a residence time of 2.5 hours and at a polymerization 
temperature so as to yield a polymer having the intrinsic viscosity as 
shown in Table 1 below. 
After completion of the polymerization, the resulting ethylenic polymer was 
tested for its various physical properties. 
The test results are shown in Table 2 below. 
Example 2 
The procedures of Example 1 was followed except for changing the 
polymerization conditions of the first stage and of the second stage to 
those as indicated in Table 1 below. 
The physical properties of the resulting polymer are shown in Table 2 
below. 
Example 3 
A 200-liter polymerization reactor of the first stage was continuously 
charged with ethylene at the rate of 1 kg per hour, hexane at the rate of 
15 liters per hour, and butene-1 at the rate of 20 grams per hour. To this 
mixture were added the catalyst as prepared in Example 1 above at the rate 
of 0.6 millimole, when converted into Ti, and triisobutylaluminium at the 
rate of 18 millimole per hour. 
The polymerization was carried out at a residence time of 4 hours and at 
the temperature so as to yield a polymer having the intrinsic viscosity as 
shown in Table 1 below. 
The content of the first stage reactor was transferred continuously to a 
200-liter polymerization vessel of the second stage at a given velocity. 
The second stage reactor was continuously charged with ethylene at the rate 
of 9 kg per hour, hexane at the rate of 14 liters per hour, butene-I at 
the rate of 50 grams per hour, and hydrogen, and the polymerization was 
carried out at 80.degree. C. and a residence time of 2.5 hours. 
Example 4 
The procedures of Example 3 was followed except for changing the 
polymerization conditions for the reactors of the first stage and of the 
second stage to those as indicated in Table 1 below. 
The physical properties of the resulting polymer are shown in Table 2 
below. 
Comparative Example 1 
(1) Preparation of solid catalyst component 
A suspension was prepared by adding 1.0 kg (8.8 moles) of magnesium 
diethoxide and 1.5 kg (8.8 moles) of commercially available anhydrous 
magnesium sulfate to 50 ml of n-heptane. To this suspension were added 
1.06 kg (8.8 moles) of silicon tetrachloride and 1.6 kg (35.2 moles) of 
ethanol, and the mixture was subjected to reaction at 80.degree. C. over 
the period of 3 hours. After addition of 5 liters (45 moles) of titanium 
tetrachloride, the reaction was further continued at 98.degree. C. for 3 
hours. After completion of the reaction, the reaction mixture was cooled 
and the supernatant liquid resulting from standing was removed by 
decantation. 
After addition of 100 liters of n-heptane, a washing operation consisting 
of stirring, standing and removal of the supernatant liquid was repeated 
three times. Thereafter, addition of 200 liters of n-heptane yielded 
dispersion of the solid catalyst component. The solid catalyst component 
was measured by colorimetry for its amount of titanium deposited thereon 
and it was found that the Ti amount was 42 mg-Ti/g-carrier. 
(2) Preparation of ethylenic copolymer 
Ethylenic copolymer was prepared in the same manner as in Example 3 except 
for feeding the solid catalyst component as prepared in item (1) above, as 
the catalyst component, at the rate of 1.8 millimoles per hour, when 
converted into Ti, diethylaluminium chloride at the rate of 49.7 
millimoles per hour, and triethylaluminium at the rate of 4.3 millimoles 
per hour. 
Comparative Example 2 
A 200-liter polymerization reactor of the first stage was continuously 
charged with ethylene at the rate of 5 kg per hour, hexane at the rate of 
15 liters per hour, and hydrogen so as to produce a polymer having the 
intrinsic viscosity as shown in Table 1 below. Furthermore, the reactor 
was then charged with the catalyst, as used in Example 1, at the rate of 
0.5 millimole per hour, when converted into Ti, and triisobutylaluminium 
at the rate of 15.0 millimole per hour. The mixture was subjected to 
polymerization at 80.degree. C. and a residence time of 4 hours. The 
content of the first stage reactor was then transferred continuously at a 
given speed to a hydrogen-deaerating vessel. 
After deaeration of hydrogen, the reaction mixture was then transferred to 
a 200-liter polymerization reactor of the second stage which in turn was 
continuously charged with ethylene at the rate of 5 kg per hour, hexane at 
the rate of 15 liters per hour, butene-1 at the rate of 100 grams per 
hour, and hydrogen so as to yield a polymer having the intrinsic viscosity 
as shown in Table 1 below. The mixture was then subjected to 
polymerization at a residence time of 2.5 hours and the polymerization 
temperature at 80.degree. C. , thereby yielding an ethylene copolymer. It 
was then measured for its physical properties and they are shown in Table 
2 below. 
Comparative Example 3 
The polymerization at the first stage was carried out using the same solid 
catalyst component as prepared in Comparative Example I above in the same 
manner as in Example 3. The resulting reaction mixture in the first stage 
reactor was continuously transferred at a given speed to a 200-liter 
polymerization reactor of the second stage. The first stage reactor was 
continuously charged with ethylene at the rate of 5 kg per hour, hexane at 
the rate of 2 liters per hour, and hydrogen so as to yield a polymer 
having the intrinsic viscosity as shown in Table 1 below. The 
polymerization was carried out at 80.degree. C. and a residence time of 4 
hours. After the content in the reactor was continuously transferred at a 
given speed to a hydrogen-deaerating vessel and hydrogen was deaerated, 
the reaction mixture was further transferred to a 200-liter polymerization 
reactor of the third stage which in turn was continuously charged with 
ethylene at the rate of 3.75 kg per hour, hexane at the rate of 12 liters 
per hour, butene-1 at the rate of 42 grams per hour, and hydrogen so as to 
produce a polymer having the intrinsic viscosity as shown in Table 1 
below, thereby subjecting the mixture to polymerization at 80.degree. C. 
and a residence time of 2.5 hours. 
Comparative Example 4 
A 200-liter polymerization reactor of the first stage was continuously 
charged with ethylene at the rate of 5 kg per hour, hexane at the rate of 
15 liters per hour, and hydrogen so as to yield a polymer having the 
intrinsic viscosity as shown in Table 1 below. The first stage reactor was 
further charged continuously with the solid catalyst component, as used in 
Comparative Example 1, at the rate of 1.4 millimoles, when converted into 
Ti, diethylaluminium chloride at the rate of 39.2 millimoles per hour, and 
triethylaluminium at the rate of 3.4 millimoles per hour, and the 
polymerization was carried out at 80.degree. C. and a residence time of 4 
hours. After the content in the reactor was continuously transferred at a 
given speed to a hydrogen-deaerating vessel and hydrogen was deaerated, 
the reaction mixture was further transferred to a 200-liter polymerization 
reactor of the second stage which in turn was continuously charged with 
ethylene at the rate of 5 kg per hour, hexane at the rate of 15 liters per 
hour, butene-1 at the rate of 100 grams per hour, and hydrogen so as to 
produce a polymer having the intrinsic viscosity as shown in Table 1 
below, thereby subjecting the mixture to polymerization at 80.degree. C. 
and a residence time of 2.5 hours. Its measured physical properties are 
shown in Table 2 below. 
Table 1 below indicates polymerization conditions of each step and Table 2 
below indicates the results obtained by measurement for their physical 
properties of the ethylenic polymer compositions. 
TABLE 1 
__________________________________________________________________________ 
FIRST STAGE SECOND STAGE 
POLYMER- 
AMOUNT POLYMER- 
AMOUNT 
TEMP. INTRINSIC 
IZATION 
OF TEMP. 
INTRINSIC 
IZATION 
OF 
.degree.C. VISCOSITY 
RATE BUTENE 1 
.degree.C. 
VISCOSITY 
RATE BUTENE-1 
__________________________________________________________________________ 
EX. 1 80 2.6 94 0.7 45 24 6 0 
EX. 2 80 2.7 94 0.7 50 20 6 0 
EX. 3 42 25 10 2.0 80 2.0 90 0.6 
EX. 4 50 20 10 2.0 80 2.5 90 0.7 
CO.EX. 1 
38 25 10 0.5 80 2.0 90 0.8 
CO.EX. 2 
80 2.0 50 0 80 5.9 50 2.0 
CO.EX. 3 
38 25 10 0.5 80 0.7 50 0 
CO.EX. 4 
80 2.0 50 0 80 5.9 50 2.0 
__________________________________________________________________________ 
THIRD STAGE FINAL STAGE 
INTRINSIC 
POLYMERIZATION 
AMOUNT OF 
DENSITY, 
INTRINSIC 
TEMP. .degree.C. 
VISCOSITY 
RATE BUTENE 1 
g/cm.sup.3 
VISCOSITY 
__________________________________________________________________________ 
EX. 1 -- -- -- -- 0.952 3.45 
EX. 2 -- -- -- -- 0.953 3.53 
EX. 3 -- -- -- -- 0.950 3.93 
EX. 4 -- -- -- -- 0.952 3.95 
CO.EX. 1 -- -- -- -- 0.950 3.80 
CO.EX. 2 -- -- -- -- 0.952 3.95 
CO.EX. 3 80 3.0 40 1.0 0.952 3.98 
CO.EX. 4 -- -- -- -- 0.952 3.94 
__________________________________________________________________________ 
Intrinsic viscosity : dl/g 
Polymerization ratio :rate of polymerization with respect to total amount 
of polymerization in each stage (% by wt) 
Amount of Butene1 : ratio of polymerization of butene1 with respect to 
amount of polymerization in each stage 
TABLE 2 
__________________________________________________________________________ 
THICKNESS 
PINCH-OFF OF MELT TENSILE IZOD IMT 
THICKNESS CONVEX PORTION 
ELASTICITY 
MODULUS STRENGTH 
(mm) (mm) (g) (kg/cm.sup.2) 
E S C R 
kg,cm/cm 
__________________________________________________________________________ 
EX. 1 5.7 5.5 41 11900 210 70 
EX. 2 6.4 5.3 36 11400 350 66 
EX. 3 7.4 4.6 39 11800 600&lt; 56 
EX. 4 6.5 5.3 34 11300 600&lt; 70 
CO.EX. 1 
4.5 3.8 36 11400 600&lt; 62 
CO.EX. 2 
2.7 2.1 21 11400 600&lt; 80 
CO.EX. 3 
2.9 2.2 34 12100 600&lt; 43 
CO.EX. 4 
2.6 2.1 19 12000 600&lt; 72 
__________________________________________________________________________ 
Example 5 
(1) Preparation of Mg-containing solid composite 
To 10 liters of n-heptane were added 1 kg (3.8 moles) of diethoxymagnesium 
and 1.9 kg (5.6 moles) of tetra-n-butoxytitanium, and the mixture was 
heated at 100.degree. C. for 3 hours, thereby producing a homogeneous 
solution which in turn was dropwise added at 20.degree. C. over the period 
of 1 hour to 12 liters of propanol. After completion of the dropwise 
addition, the mixture was further stirred for additional 1 hour. The 
resulting solid was washed with dry hexane until no Ti could be detected 
in the washed solution. The resulting solid composite was found to have a 
specific surface area of 130 m.sup.2 per gram and a titanium content of 
0.62% by weight. 
(2) Preparation of solid catalyst component 
A solution of 450 grams (1.2 moles) of tetra-n-butoxyzirconium and 200 
grams (0.6 mole) of tetra-n-butoxytitanium in 5 liters of hexane was 
dropwise added at 20.degree. C. to the Mg-containing solid composite 
slurry, as obtained in item (1) above, over the period of 15 minutes with 
stirring. After completion of the dropwise addition, the reaction mixture 
was further reacted under reflux for 90 minutes. To this reaction mixture 
was dropwise added 10.2 liters of a 50% by weight hexane solution of 
ethylaluminium dichloride at 20.degree. C. over the period of 30 minutes 
with stirring, and the resulting mixture was further reacted under reflux 
for 60 minutes after completion of the dropwise addition. The resulting 
solid catalyst component was washed well with dry hexane until no chlorine 
could be detected any more. Thereafter, the washing of the resulting 
product was repeated and the total hexane volume containing the solid 
catalyst component was made 50 liters. It was found that the Ti content 
and the Zr content in the solid catalyst component were 1.76% by weight-Ti 
and 6.10% by weight-Zr, respectively, when converted into the 
corresponding single metal. 
(3) Ethylenic copolymer 
A 200-liter polymerization reactor of the first stage was continuously 
charged with ethylene at the rate of 9 kg per hour, hexane at the rate of 
26 liters per hour, butene-1 at the rate of 72 grams per hour and hydrogen 
so as to produce a polymer having the intrinsic viscosity as shown in 
Table 3 below. Furthermore, the reactor was then charged with the 
catalyst, prepared hereinabove, at the rate of 0.6 millimole per hour, 
when converted into Ti, and triisobutylaluminium at the rate of 18 
millimole per hour. The mixture was subjected to polymerization at 
80.degree. C. and a residence time of 3 hours. The content of the first 
stage reactor was then transferred continuously at a given speed to a 
hydrogen-deaerating vessel. 
After deaeration of hydrogen, the reaction mixture was then transferred to 
a 200-liter polymerization reactor of the second stage which in turn was 
continuously charged with ethylene at the rate of 1 kg per hour and hexane 
at the rate of 3 liters per hour. The mixture was then subjected to 
polymerization at a residence time of 2.5 hours and at a polymerization 
temperature so as to yield a polymer having the intrinsic viscosity as 
shown in Table 3 below. 
After completion of the polymerization, the resulting ethylenic polymer was 
tested for its various physical properties. 
The test results are shown in Table 4 below. 
Examples 6-10 
The procedures of Example 5 was followed except for changing the 
polymerization conditions of the first stage and of the second stage to 
those as indicated in Table 3 below. 
The physical properties of the resulting polymer are shown in Table 4 
below. 
Example 11 
A 200-liter polymerization reactor of the first stage was continuously 
charged with ethylene at the rate of 1 kg per hour, hexane at the rate of 
15 liters per hour, butene-1 at the rate of 20 grams per hour and hydrogen 
and further with the catalyst, as used in Example B above, at the rate of 
0.6 millimole per hour, when converted into Ti, and triisobutylaluminium 
at the rate of 18 millimole per hour. The mixture was subjected to 
polymerization at a residences time of 4 hours and at the temperature at 
which the polymer having the intrinsic viscosity as shown in Table 3 below 
was obtained. The reaction mixture in the first stage reactor was then 
transferred continuously at a given speed to a 200-liter polymerization 
reactor of the second stage which in turn was continuously charged with 
ethylene at the rate of 9 kg per hour, hexane at the rate of 14 liters per 
hour, butene-1 at the rate of 50 grams per hour, and hydrogen so as to 
yield the polymer having the intrinsic viscosity as shown in the table 
below. Then the mixture was subjected to polymerization at a residence 
time of 2.5 hours and at a polymerization temperature of 80.degree. C. 
Example 12 
The procedures of Example 11 was followed except for changing the 
polymerization conditions for the reactors of the first stage and of the 
second stage to those as indicated in Table 3 below. 
The physical properties of the resulting polymer are shown in Table 4 
below. 
Comparative Example 5 
(1) Preparation of solid catalyst component 
A suspension was prepared by adding 1.0 kg (8.8 moles) of magnesium 
diethoxide and 1.06 kg (8.8 moles) of commercially available anhydrous 
magnesium sulfate to 50 ml of n-heptane. To this suspension were added 1.5 
kg (8.8 moles) of silicon tetrachloride and 1.6 kg (35.2 moles) of 
ethanol, and the mixture was subjected to reaction at 80.degree. C. over 
the period of 1 hours. After addition of 5 liters (45 moles) of titanium 
tetrachloride, the reaction was further continued at 98.degree. C. for 3 
hour. After completion of the reaction, the reaction mixture was cooled 
and the supernatant liquid resulting from standing was removed by 
decantation. After addition of 100 liters of n-heptane and stirring, a 
washing operation consisting of stirring, standing and removal of the 
supernatant liquid was repeated three times. Thereafter, addition of 200 
liters of n-heptane yielded dispersion of the solid catalyst component. 
The solid catalyst component was measured by colorimetry for its amount of 
titanium deposited thereon and it was found that the Ti amount was 42 
mg-Ti/g-carrier. 
(2) Preparation of ethylenic copolymer 
Ethylenic copolymer was prepared in the same manner as in Example 11 except 
for feeding the solid catalyst component as prepared in item (1) above, as 
the catalyst component at the rate of 1.8 millimoles per hour, when 
converted into Ti, diethylaluminium chloride at the rate of 49.7 
millimoles per hour, and triethylaluminium at the rate of 4.3 millimoles 
per hour. 
Comparative Example 6 
A 200-liter polymerization reactor of the first stage was continuously 
charged with ethylene at the rate of 5 kg per hour, hexane at the rate of 
15 liters per hour, and hydrogen so as to yield a polymer having the 
intrinsic viscosity as shown in Table 3 below. The first stage reactor was 
further charged continuously with the solid catalyst component, as used in 
Comparative Example 5, at the rate of 0.5 millimoles, when converted into 
Ti, triisobutylaluminium chloride at the rate of 15.0 millimoles per hour, 
and the polymerization was carried out at 80.degree. C. and a residence 
time of 4 hours. After the content in the reactor was continuously 
transferred at a given speed to a hydrogen-deaerating vessel and hydrogen 
was deaerated, the reaction mixture was further transferred to a 200-liter 
polymerization reactor of the second stage which in turn was continuously 
charged with ethylene at the rate of 5 kg per hour, hexane at the rate of 
15 liters per hour, butene-1 at the rate of 100 grams per hour, and 
hydrogen so as to produce the ethylene copolymer having the intrinsic 
viscosity as shown in Table 3 below, thereby subjecting the mixture to 
polymerization at 80.degree. C. and a residence time of 2.5 hours. Its 
measured physical properties are shown in Table 4 below. 
Comparative Example 7 
The polymerization at the first stage was carried out using the same solid 
catalyst component as prepared in Comparative Example 5 above in the same 
manner as in Example 11. The resulting reaction mixture in the first stage 
reactor was continuously transferred at a given speed to a 200-liter 
polymerization reactor of the second stage. The second stage reactor was 
continuously charged with ethylene at the rate of 5 kg per hour, hexane at 
the rate of 2 liters per hour, and hydrogen so as to yield a polymer 
having the intrinsic viscosity as shown in Table 3 below. The 
polymerization was carried out at 80.degree. C. and a residence time of 4 
hours. After the content in the reactor was continuously transferred at a 
given speed to a hydrogen-deaerating vessel and hydrogen was deaerated, 
the reaction mixture was further transferred to a 200-liter polymerization 
reactor of the third stage which in turn was continuously charged with 
ethylene at the rate of 3.75 kg per hour, hexane at the rate of 12 liters 
per hour, butene-1 at the rate of 42 grams per hour, and hydrogen so as to 
produce a polymer having the intrinsic viscosity as shown in Table 3 
below, thereby subjecting the mixture to polymerization at 80.degree. C. 
and a residence time of 2.5 hours. 
Comparative Example 8 
A 200-liter polymerization reactor of the first stage was continuously 
charged with ethylene at the rate of 5 kg per hour, hexane at the rate of 
15 liters per hour, and hydrogen at the rate so as to yield a polymer 
having the intrinsic viscosity as shown in Table 3 below. The first stage 
reactor was further charged continuously with the solid catalyst 
component, as used in Comparative Example 5, at the rate of 1.4 
millimoles, when converted into Ti, diethylaluminium chloride at the rate 
of 39.2 millimoles per hour, and triethyl- aluminium at the rate of 3.4 
millimoles per hour, and the polymerization was carried out at 80.degree. 
C. and a residence time of 4 hours. After the content in the reactor was 
continuously transferred at a given speed to a hydrogen-deaerating vessel 
and hydrogen was deaerated, the reaction mixture was further transferred 
to a 200-liter polymerization reactor of the second stage which in turn 
was continuously charged with ethylene at the rate of 5 kg per hour, 
hexane at the rate of 15 liters per hour, butene-1 at the rate of 100 
grams per hour, and hydrogen so as to produce a polymer having the 
intrinsic viscosity as shown in Table 3 below, thereby subjecting the 
mixture to polymerization at 80.degree. C. and a residence time of 2.5 
hours. Its measured physical properties are shown in Table 4 below. 
TABLE 4 
__________________________________________________________________________ 
THICKNESS 
PINCH-OFF OF MELT TENSILE IZOD IMT 
THICKNESS CONVEX PORTION 
ELASTICITY 
MODULUS STRENGTH 
(mm) (mm) (g) (kg/cm.sup.2) 
E S C R 
kg,cm/cm 
__________________________________________________________________________ 
EX. 5 5.9 4.5 42 11800 300 76 
EX. 6 5.8 5.4 40 11800 200 68 
EX. 7 6.5 5.4 34 11500 360 67 
EX. 8 6.0 4.9 35 10900 310 78 
EX. 9 6.1 4.5 40 11900 600&lt; 75 
EX. 10 
5.9 5.5 38 11800 600&lt; 70 
EX. 11 
7.5 4.6 30 11900 600&lt; 54 
EX. 12 
6.6 5.4 28 11800 600&lt; 72 
CO.EX. 5 
4.6 3.9 28 11500 600&lt; 60 
CO.EX. 6 
2.7 2.1 20 11400 600&lt; 81 
CO.EX. 7 
2.9 2.2 23 12100 600&lt; 46 
CO.EX. 8 
2.5 2.0 19 12000 600&lt; 70 
__________________________________________________________________________ 
As is apparent from the test results as indicated hereinabove, the ethylene 
polymers obtained in the above examples are superior in ESCR to those 
obtained in the above comparative examples. 
As to the pinch-off fusing properties, the polymers obtained in the 
examples are higher and better in both pinch-off thickness and convex 
thickness and in melt elasticity, so that the pinch-off fusing properties 
of the polymers obtained by the process according to the present invention 
are superior to those of the polymers obtained in the comparative 
examples. 
Concerning the high-impact characteristics, the polymers obtained by the 
process according to the present invention are superior in both Izod 
impact strength and tensile modulus to those obtained in the comparative 
examples.