JPH0253811A - Ethylene copolymer - Google Patents

Abstract

PURPOSE:To provide the title copolymer produced from ethylene and an alpha-olefin, having each specific composition, intrinsic viscosity, density, fensile viscosity ratio and activation energy, high in tensile viscosity or melt tension when melted, and excellent in molding processability and resistance to environmental stress cracking. CONSTITUTION:Diethoxymagnesium and tetra-n-butoxytitanium are added to n-heptane followed by reaction under heating, and the resulting product is dripped into isopropanol to form a magnesium-contg. solid composite, which is then formulated with ethylalminum dichloride. Using the resultant catalyst, a copolymerization between ethylene and a >=3C alpha-olefin (e.g., butene-1) is carried out, thus obtaining the objective copolymer made up of 85-99.9wt.% of ethylene unit and 15-0.1wt.% of the alpha-olefin unit. This copolymer has the following characteristics: 1. intrinsic viscosity... 3.1-5.0 2. density... 0.940-0.960g/cm<3> 3. parameter A defined by the formula (Z10 and Z50 are values of tensile viscosity measured at 150 deg.C and at a constant strain rate 0.05sec<-1> for 10 and 50sec. respectively)... 6-50 4. flow activation energy H... <=7.5kcal/ mol.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a novel ethylene copolymer. More specifically, the present invention relates to an ethylene copolymer that has sufficiently high elongational viscosity and melt tension when melted, and has excellent moldability and environmental stress cracking resistance (hereinafter referred to as ESCR) in blow molding. be.

The ethylene copolymer of the present invention is suitably used in the field of blow molding, particularly large-sized blow molding.

Background of the Invention In recent years, polyethylene has been attracting attention for use in ultra-large containers such as automobile fuel tanks and drums, but polyethylene used for this purpose has a high melt tension.
Good impact resistance and ESCR are required.

When using a Ziegler catalyst, it is known that the condition for obtaining such favorable properties is, for example, to widen the molecular weight distribution. Mixing method (Japanese Patent Publication No. 45-3215, Japanese Patent Application Laid-open No. 57-133136), multi-stage polymerization method (Japanese Patent Publication No. 46-11349,
Japanese Unexamined Patent Publication No. 52-19788) has been proposed.

On the other hand, methods for improving moldability and ESCR include:
A method of mixing polyethylene produced using a Ziegler catalyst and polyethylene produced using a chromium catalyst,
Methods of mixing high-density polyethylene and low-density polyethylene are also known (JP-A-59-196345, JP-A-54-100444), but these methods have the disadvantage of insufficient melt tension. There is.

Problems to be Solved by the Invention The present invention overcomes the drawbacks of conventional polyethylene, and creates an ethylene copolymer that has sufficiently high melt tension when melted and has excellent moldability and ESCR in blow molding. This was done for the purpose of providing integration.

Means for Solving the Problems The present inventors have developed a material with high melt tension, impact resistance, and ES.
As a result of various studies to develop an ethylene copolymer with excellent CR, we found that other α-
We discovered that an ethylene copolymer, which is a copolymer of olefins and whose intrinsic viscosity, parameter A, and flow activation energy are adjusted to specific ranges, is suitable for this purpose, and based on this knowledge, we developed this book. The invention was completed.

That is, the present invention provides a copolymer consisting of 85 to 99.9% by weight of ethylene units and 15 to 0.1% by weight of olefin units having 3 or more carbon atoms, and having an intrinsic viscosity of 3.1 to 5.
．． 0, density 0.940-0.96h/cm3, formula %
Formula % (Z+o and 250 are measurement temperature +50°C1 strain rate 00
5 sec-' constant strain rate extensional viscosity 1Qse respectively
The present invention provides an ethylene copolymer characterized by having a parameter A defined by 6 to 50 (value at c and 50 sec) and a flow activation energy ΔH of 7.5 KcaQ/moQ or less. .

The present invention will be explained in detail below.

The ethylene copolymer of the present invention is a copolymer of ethylene and a-olefin, and contains 0.1 to 15% by weight, preferably 0.2 to 5% by weight of α-olefin units having 3 or more carbon atoms. It is necessary to contain it in a certain proportion. If the proportion of α-olefin units is less than this, it is difficult to obtain desirable properties as a copolymer, and if it is greater than this, the rigidity of the copolymer decreases.

Further, the copolymer of the present invention needs to have an intrinsic viscosity of 3.1 to 5.0 d12/g, preferably 3.5 to 4.5 d12/g, measured in decalin at 135°C.

If the intrinsic viscosity is less than 3.1'dfl/g, the strength will decrease and the moldability will be unfavorable, and if it exceeds 5.0607g, the moldability will decrease.

Further, in the copolymer of the present invention, in the extensional viscosity curve showing the relationship between extensional viscosity and time, the parameter A defined by the following formula must be 6 to 50, preferably 9 to 15.

A = Z s. /Zt.

(z, . and Zs'o are measured at a temperature of 150°C and a constant strain rate of 05 sec-' for each 10 s of elongational viscosity.
These are the values at ec and 50 sec. ) This extensional viscosity is a material constant that greatly affects the melt tension during extensional deformation, and is usually expressed as a function of strain rate (deformation rate) and time. If this A value is less than 6, the entanglement or unraveling between molecules is easy, and the increase in viscosity during elongation is small.
Thickness deviation during molding becomes large, and if it exceeds 50, stretching breaks occur during melting.

Furthermore, in the copolymer of the present invention, the flow activation energy Δ■] defined by the following formula is 7.5 Kca1
2/moα or less, preferably 5.9-7.2Kca1
2/mo12°, more preferably 5.9 to 6.9 Kca
Must be O/moc.

△H= 13-6X QogB (where B is the frequency range 10”-6X 102ra
d/sec, storage modulus G1'-frequency W curves obtained at measurement temperatures of 150°C and 220°C are superimposed using the usual "superposition principle". This indicates the amount of frequency axis movement) If it exceeds 7.5 Kcal/moQ, the temperature dependence of the viscoelasticity is large, the residual stress is also large, and the ES
CR worsens.

Further, the copolymer of the present invention has a density of 0.940 to 0.96.
0g/'cm3, preferably sail 945- (L955g
/cm3 is preferred. This density is sail 94
If it is less than 0g/cm3, the rigidity will decrease and
．． If it exceeds 960 g/cm3, the impact strength will decrease.

In order to control the parameters A and ΔH, for example, a certain type of catalyst may be used, or a polymer having a molecular weight of 1,000,000 or more may be added by 2 to 20% in a certain stage polymerization vessel in multistage polymerization.
There are ways to generate it.

Next, the copolymer of the present invention is produced by copolymerizing 85% by weight or more of ethylene with an α-olefin having 3 or more carbon atoms. There are various kinds of α-olefins having 3 or more carbon atoms, for example, 3 to 10 carbon atoms.
, preferably 3 to 6 α-olefins, specifically propylene, butene-11hexene-11octene-1, and the like.

Examples of catalysts used in this copolymerization reaction include Ti
- Binary transition metal catalysts such as Zr and Ti-V, TEA/
A catalyst consisting of a mixed promoter such as DEAC or TIBA/DEAC and a third component such as an ester is used.

Specifically, the Ziegler type, for example, JP-A-57-
12006, JP-A-57-12007, JP-A-5! If-227913 Publication, Patent Application 1986-13
Those described in No. 7712 can be used. That is, as such a catalyst, for example, (A) a solid content produced by reacting a compound containing at least titanium, magnesium and a halogen with tetraalkoxyzirconium and/or zirconium tetrahalide contains an alkoxy group. A solid product obtained by reacting a good halogen-containing titanium compound and (B) a product containing an organoaluminum compound as an active ingredient, and (A) a solid product obtained by reacting a compound containing at least titanium, magnesium, and a halogen with tetraalkoxyzirconium. A solid product obtained by reacting an organoaluminum halide with the solid content produced; (B) a product containing an organoaluminum compound as an active ingredient; (A) a solid catalyst component containing at least titanium, magnesium, and a halogen; B)
A compound containing an organoaluminum compound as a main component, (A) a mixture of magunsium dialkogide and titanium tetraalkoxide, is brought into contact with an alkanol such as Impropanoflu to form a magnesium-containing solid composite, which is then injected with zirconyl aluminum compound. A product consisting of a solid catalyst component prepared by reacting I.ra alkoxide or zirconium tetrahalide, or both, and further adding organic aluminum halide to the resulting reaction product and reacting the same, and (B) an organoaluminum compound component. Examples include.

Among these, in particular, the molar ratio of Zr and T1 is 0.5 to 2.
It is preferable to set it to 0.

Examples of the above-mentioned compounds containing at least titanium, magnesium and halogen include solid substances obtained by reacting titanium halides with magnesium inorganic compounds such as magnesium oxide, magnesium hydroxide, magnesium carbonate, magnesium sulfate, and magnesium halides;
Or a solid substance obtained by reacting various magnesium compounds with silicon halide, alcohol, and titanium halide, or a solid substance obtained by reacting dialkoxymagnesium such as magnesium jetoxide with magnesium sulfate and titanium halide. can be mentioned. In addition, a silicon halide or organosilicon compound (for example, 5icQ4. CH30S
ICI23, (CH30)2-5iC122, (CH3
0)3SiC(2,Si(OCH3)iC2H503I
CI23, (CJaO)2SiC02, (C2HaO)
ssic12.5i (OCJs)4, etc.) and a solid material obtained by reacting titanium halides, and other materials such as dialkoxymagnesium and Mg
It is also possible to use a solid substance obtained by reacting an alcohol adduct of magnesium halide such as C42.6C2H,OH, and then reacting the product obtained by alcohol treatment with titanium halide.

Examples of the halogen-containing titanium compound that may contain a noalkoxy group include TiCl2 and TiBr.

Ti(OCJ)C(28, Ti(OC2H5)2C42
, Ti(OC2H6)3c12 nato, or a mixture thereof.

Examples of the organoaluminum compounds include trimethylaluminum, triethylaluminum, triisopropylaluminum, triisobutylaluminum, diethylaluminum monochloride, diisopropylaluminum monochloride, diisobutylaluminum monochloride, dioctylaluminum monochloride, ethylaluminum dichloride, diethylaluminum monoethoxy Examples include chloride, isopropylaluminum dichloride, and ethylaluminum sesquichloride.

Examples of the organic aluminum halide include dimethylaluminum monochloride, diethylaluminum monochloride, diisopropylaluminium monochloride, diisobutylaluminum monochloride, methylaluminum dichloride, ethylaluminum dichloride, isopropylaluminum dichloride, isobutylaluminum monochloride, etc., or mixtures thereof. can be mentioned.

The titanium tetraalkoxide or zirconium alkoxide has the general formula % (1) (wherein R is an alkyl group having 1 to 20 carbon atoms, a cycloalkyl group, an aryl group, or an aralkyl group, and M is titanium or zirconium. ), and
Such compounds include, for example, tetramethoxytitanium, tetrae]quintitanium, tetra(n-propoquino)
Titanium, Tetra(n-butoxy)titanium, Tetra(n-butoxy)
-pentoxy)titanium, tetra(n-hexoxy)titanium, tetra(n-heptoxy)titanium, tetra(n-octoxy)titanium, tetracyclopene I xytitanium, tetracyclohexoxytitanium, tetracyclopene I xytitanium, tetra(n-hexoxy)titanium, tetra(n-hexoxy)titanium Examples include cyclooctoxytitanium, tetraphenoxytitanium, and zirconium compounds corresponding to these titanium compounds.

There are no particular restrictions on the polymerization method and conditions, and solution polymerization, suspension polymerization, gas phase polymerization, etc. are all possible, as well as continuous polymerization and discontinuous polymerization, as well as stage polymerization. It is also possible to carry out multistage polymerization. As the reaction medium, inert solvents such as butane, pentane, n-hexane, cyclohexane, heptane, benzene, and toluene are preferred. Furthermore, the reaction pressure is 0.5-15kg/
cm2G, preferably 1-10 kg7 cm2G, and the reaction temperature is 50-10000, preferably 60-95
°C, the desired ethylene copolymer can be obtained by reacting for 10 minutes to 5 hours, preferably 30 minutes to 3 hours.

The molecular weight during polymerization may be controlled by known means such as hydrogen treatment.

Effects of the Invention The ethylene copolymer of the present invention has sufficiently high melt tension when melted, and has good moldability and ESC in blow molding etc.
It has excellent R and can be suitably used as a material for blow molding.

Example Next, the present invention will be explained in more detail with reference to Examples.

In addition, the measurement of each physical property was performed as follows.

(1) Intrinsic viscosity Measurements were made in decalin at 135°C.

(2) Density Measured in accordance with JISK7112.

(3) Parameter A A length of 30 cm was created using a 20 mm 1 small extruder (rotation speed 5 rpm, set temperature 190°C) manufactured by Toyo Seiki Co., Ltd. using a stretching rheometer manufactured by Roki Seisakusho Co., Ltd. as a measuring device. A cylindrical sample with a diameter of 3 mm was placed in silicone oil at 150°C for 15 minutes, then attached to a rotating roller, and after removing the "sag" of the sample, it was stretched at a predetermined roller rotation speed to adjust the tension and sample diameter. Changes over time were measured. From this change in diameter over time, the strain rate is calculated according to the following equation.

(do: initial diameter, d(t): diameter after seconds, L: strain rate, and d(t) was measured using a video with a timer.) Next, from this strain rate, the extensional viscosity was determined according to the following formula. is calculated.

Z(εt)=F(t)/S(t)M(F(t
): tension after seconds, S (t): d (cross-sectional area calculated from It is calculated using the extensional viscosity according to the following formula.

A-Z　s. /Z,.

(2+o and Z5o are 150°C1 strain speed sail 05sec
-' constant strain rate extensional viscosity of 1Qsec and 5 respectively
This is the value at 0 sec. ) (4) Flow activation energy △H As a measuring device, System 4 manufactured by Rheometrics was used.
using a parallel plate type jig at a temperature of 150°C12
Measure the storage modulus G' in the frequency range 1O-2 to 6X 102 at 20°C, find the frequency axis movement amount B from the two G' curves, and calculate the flow activation energy △11 according to the following formula.
I asked for

△H-13-6 In order of die, 180, 190, 200, 22 respectively.
Containers were obtained as molded articles weighing 5 kg in a molding cycle of 5 minutes at temperatures of 0°220, 220 and 220°C.

The wall thickness of the obtained container was measured as follows.

■Pinch-off thickness The center of the pinch-off part at the bottom of the container was cut out at right angles to the pinch-off part, and the minimum thickness of the pinch-off part was measured using a caliper.

■Protrusion thickness The area near the mold protrusion at the top of the container was cut out in a direction perpendicular to the pinch-off part, and the minimum wall thickness was measured using a caliper.

Example 1 (1) Production of Mg-containing solid composite n-hebutane 100. Mg(OEt)z l 72
g(8,8moθ) and Ti(0-n-Bu)tl, 9
Add J2g (5,6mo(1)) and heat at 100°C for 3 hours to make a homogeneous solution.The entire amount of this homogeneous solution was placed in isopropanol 12Q while stirring at 20°C.
Add drops after 1 hour and continue stirring for another hour. The resulting solid is washed with dry hexane until no Ti is detected in the washing solution. The resulting solid composite had a specific surface area of 130+++2/g and a titanium content of 0.62% by weight.

(2) Production of solid catalyst component Hexane 5111 in which 450 g (1,2 moQ) of Zr (0-n-Bu) and 200 g (0,6 mo α) of Ti (0-n-Bu) were dissolved was obtained in (1). The Mg-containing solid composite slurry was heated to a temperature of 20°O''c while stirring.
' It was added dropwise over 15 minutes, and the reaction was continued for 90 minutes under reflux. EtA12 (50 wt% hexane dilution of 42 1
While stirring, 0.2Q was added dropwise at 20°C over 30 minutes, and the mixture was further reacted for 60 minutes under reflux. Wash with dry hexane until no chlorine is detected in the solution, and bring the total volume to 500 with hexane. The content of Ti and Zr in the solid catalyst component is 1.76% by weight in terms of elemental metal.
-Ti, 6.10% by weight -Zr.

(3) Production of ethylene copolymer 972 g of ethylene/
11r1 hexane 26Q/hr, butene-172g/
hr and hydrogen are continuously fed to obtain a polymer having the intrinsic viscosity shown in the table, and the catalyst is
Polymerization was carried out at 80° C. with a residence time of 3 hours. The contents of the polymerization vessel are continuously led to a hydrogen degassing tank at a predetermined rate, and after separating hydrogen,
It was led to a second stage polymerization reactor with a capacity of 200Q. The second stage polymerization reactor was charged with 1 kg/hr of ethylene and 31 kg/hr of hexane.
2/hr was continuously supplied, and the polymerization was carried out under the conditions of a residence time of 25 hours at a polymerization temperature such that a polymer having the intrinsic viscosity shown in the table was obtained.

After the reaction was completed, the obtained ethylene copolymer was subjected to various physical property tests. Measurements of these physical properties are shown in the table.

Example 2 2000. 1 kg of ethylene/
hr, Hexa 715 Q/ hr, Butene-120g/
hr was continuously supplied, and the catalyst used in Example 1 was introduced at a rate of 0.6 mmol/hr in terms of T1 and 18 mmol/br of triisobutylaluminum to obtain a polymer having the intrinsic viscosity shown in the table. The polymerization was carried out at a polymerization temperature of 4 hours and a residence time of 4 hours.

The contents of the polymerization vessel were continuously introduced at a predetermined rate to a second stage polymerization reactor having a capacity of 200Q. The second stage polymerization reactor was supplied with 9 kg/hr of ethylene and 1412/hr of hexane.

Butene-150 g/hr and hydrogen were continuously fed to obtain a polymer having the intrinsic viscosity shown in the table,
Polymerization was carried out at 1°C with a residence time of 2.5 hours.

Example 3 The first stage was polymerized in the same manner as in Example 2. The contents of the polymerization vessel were continuously introduced at a predetermined rate to a second stage polymerization reactor having a capacity of 200Q. In the second stage polymerization reactor, ethylene 512
g/hr, hexane 20/hr, and hydrogen were continuously fed to obtain a polymer having the intrinsic viscosity shown in the table, and the polymerization was carried out at a go'c with a residence time of 4 hours.

The entire contents of the polymerization vessel were continuously led to a hydrogen degassing tank at a predetermined rate, and after separating hydrogen, the contents were led to a third-stage polymerization reactor with a capacity of 200Q. In the third stage polymerization reactor, ethylene 3.7572
g/hr, hexane 12 (2/hr, butene-142
g/hr and hydrogen were continuously fed so as to obtain a polymer having the intrinsic viscosity shown in the table, and the polymerization was carried out at 80° C. with a residence time of 2.5 hours.

Example 4 (1) Preparation of solid catalyst component Magnenium diethoxide 1. 1.06 kg (8.8 mol) of commercially available anhydrous magnesium sulfate and 1.5 kg (8.8 mol) of silicon tetrachloride and 1.5 kg (8.8 mol) of silicon tetrachloride were suspended.
6 kg (35.2 mol) was added and the reaction was carried out at 80°C for 1 hour.

Next, 5 ff (45 mol) of titanium tetrachloride was added and heated to 98°.
The reaction was carried out at C for 3 hours. After the reaction, the mixture was cooled and left to stand, and the supernatant liquid was removed by a decanting method. Next, add 100 ml of n-heptane
ff was added, stirred, left to stand, and the supernatant liquid removed. After washing operations were performed three times, n-hebutane 200a was added to obtain a dispersion liquid of the solid catalyst component. The amount of titanium supported on this product was determined by a colorimetric method, and as a result, it was 42 mg - 7 g of Ti - carrier.

(2) Production of ethylene copolymer As catalyst components, the solid catalyst component in (1) above was used at 1.8 mmol/hr in terms of Ti, diethylaluminium chloride at 49.7 mmol/h, and triethylaluminum at 4.3 mmol/hr. An ethylene copolymer was obtained in the same manner as in Example 2 except that the amount was supplied at mmol/hr.

Comparative Example 1 Using the solid catalyst component produced in Example 4, an ethylene copolymer was obtained in the same manner as in Example 3. The results of measuring the physical properties of this material are shown in the table.

Comparative Example 2 572 g of ethylene was added to the first stage polymerization reactor with a capacity of 200 Q.
br, 15 L'hr of hexane, and hydrogen were continuously fed so as to obtain a polymer having the intrinsic viscosity shown in the table, and the solid catalyst component used in Example 4 was added to 15 L'hr of hexane in terms of T1.
．． 4 mmol/hr, diethylaluminum chloride at 39.2 mmol/hr, l-ethylaluminum 3.4 mmol/hr, polymerization temperature 80°.
Polymerization was carried out under conditions of a C1 residence time of 4 hours. The contents of the polymerization vessel were continuously introduced into a hydrogen degassing tank at a predetermined rate, and after hydrogen was separated, the contents were introduced into a second-stage polymerization reactor with a capacity of 200Q. 2
Ethylene 5 kg/hr, hexane 15 Q/hr, butene-1100 g/hr, and hydrogen were continuously supplied to the polymerization reactor at 80°C to obtain a polymer having the intrinsic viscosity shown in the table. Polymerization was carried out under conditions of a residence time of 2.5 hours to obtain an ethylene copolymer. The results of measuring the physical properties of this material are shown in the table.

Comparative Example 3 A commercial product Shorex 4551Z (manufactured by Showa Denko) was used, and its physical properties are shown in the table for comparison.

Claims (1)

[Scope of Claims] 1. A copolymer consisting of 85 to 99.9% by weight of ethylene units and 15 to 0.1% by weight of α-olefin units having 3 or more carbon atoms, and having an intrinsic viscosity of 3.1 to 5. .0, density is 0.
940 to 0.960 g/cm^3, formula A = Z_5_0/Z_1_0 (Z_1_0 and Z_5_0 are the values at 10 sec and 50 sec, respectively, of constant strain rate extensional viscosity at a measurement temperature of 150 ° C. and a strain rate of 0.05 sec^-^1. ) An ethylene copolymer having a parameter A defined by 6 to 50 and a flow activation energy ΔH of 7.5 Kcal/mol or less.