JPH0616880A - Ethylene/alpha-olefin copolymer composition - Google Patents

Abstract

PURPOSE:To obtain an ethylene/alpha-olefin copolymer compsn. excellent esp. in moldability in high-speed molding and in low-temp. mechanical properties by compounding two specific ethylene-alpha-olefin copolymers having high or medium mol.wts. with two ethylene polymers having relatively low mol.wts. CONSTITUTION:The compsn. having an intrinsic viscosity of 0.7-6.0 dl/g, a density of 0.890-0.950g/cm<3>, and an N-value obtd. by the formula of 1.7-3.5 comprises 5-85wt.% ethylene/3-18C alpha-olefin copolymer having a specified intrinsic viscosity (eta1), 5-85wt.% ethylene/3-18C alpha-olefin copolymer having a specified intrinsic viscosity (eta2), and 5-60wt.% ethylene/3-18C alpha-olefin copolymer having a specified intrinsic viscosity (eta3, and 5-60wt.% ethylene/3-18C alpha-olefin copolymer having a specified intrinsic viscosity (eta4) provided that the sum of the four copolymers is 100wt.% and that the four intrinsic viscosities are different from each other.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to an ethylene / α-olefin copolymer composition having a very wide molecular weight distribution.
More specifically, the first component and the second component, which are two types of ethylene / α-olefin copolymers, which are a high molecular weight component or a medium molecular weight component and have an extremely wide distribution of short chain branching between molecules, It consists of two types of low molecular weight ethylene homopolymer or ethylene / α-olefin copolymer, and has a good balance of physical properties such as melt elasticity, flow properties and mechanical properties. TECHNICAL FIELD The present invention relates to an ethylene / α-olefin copolymer type composition having excellent physical properties.

[0002]

2. Description of the Related Art Conventional high pressure method low density polyethylene (HP
-LDPE), that is, low-density polyethylene obtained by radical polymerization of ethylene under high temperature and high pressure using a tubular or autoclave type reactor, has a long-chain branch having a length comparable to the main chain and 1 to 6 carbon atoms. Since the structure has a short chain branch consisting of one alkyl group, it has low crystallinity and is soft. Therefore, HP-LDPE has the drawback of being inferior in mechanical properties such as environmental stress crack resistance, tensile impact value, dart impact value, and tear strength, especially high speed moldability and mechanical properties at low temperature.

On the other hand, linear low density polyethylene (LL
DPE) is an ethylene / α-olefin copolymer produced by using various processes such as a gas phase method, a slurry method, a solution method, and a high-pressure ionic polymerization method, various catalysts, and polymerization conditions. -Mechanical properties are superior to HP-LDPE because they have only short chain branches that are uniquely determined by the type of olefin. However, since LLDPE generally has a very narrow molecular weight distribution, it is inferior in melt elasticity such as melt tension and flow characteristics such as N-value, flow parameter and critical shear rate. Defects related to melt elasticity and flow characteristics mainly appear in molding processability, and specifically, decrease in extrusion amount during molding process, increase in extrusion pressure, increase in power consumption, poor high-speed moldability, surface roughness of molded products. -Problems include generation of fish eyes and heat deterioration due to heat generation in the extruder.

When the molecular weight is reduced to improve the flow characteristics of LLDPE, the mechanical properties such as impact strength and environmental stress crack resistance, especially the mechanical properties at low temperature and the melt elasticity are remarkably deteriorated. Moreover, even if the density is lowered to improve the mechanical properties, the melt elasticity is hardly improved. As described above, it was extremely difficult to improve mechanical properties of LLDPE at the same time in a well-balanced manner, especially at low temperature.

Conventionally, a method of broadening the molecular weight distribution of ethylene / α-olefin copolymers has been reported for the purpose of improving the flow characteristics (for example, JP-A-57-21409).
JP-B No. 63-47741, etc.), melt elasticity and mechanical properties, especially mechanical properties at low temperatures, are not only improved but are greatly reduced by simply broadening the molecular weight distribution. To do. Further, regarding the improvement of mechanical properties and flow properties, in an ethylene / α-olefin copolymer composed of a high molecular weight component and a low molecular weight component, the short chain branching degree of the high molecular weight component is specified and By introducing many chain branches, not only mechanical properties and fluidity but also environmental stress crack resistance (ESCR)
Attempts have also been made to improve this (Japanese Patent Laid-Open No. 54-1004).
44, Japanese Patent Publication No. 64-7096). But,
Mechanical properties, especially at low temperatures, differ greatly depending on the short chain branch distribution of the high molecular weight component, so some improvement can be seen with the above method, but especially at low temperatures, the mechanical properties and flow properties are improved. It is not a satisfactory way to do it. Further, it is impossible to improve everything including the melt elasticity in a well-balanced manner.

[0006]

In view of the above points, the present invention retains physical properties such as heat resistance, ESCR, and flexibility, and has melt elasticity, flow characteristics, mechanical characteristics, particularly unresolved in the prior art. It is an object of the present invention to provide an ethylene / α-olefin copolymer type composition excellent in high-speed moldability and mechanical properties at low temperature.

[0007]

Means for Solving the Problems As a result of intensive studies conducted by the present inventors in view of the above-mentioned objects, the inventors have found that a high molecular weight component or a medium molecular weight component and an extremely wide distribution of short chain branches between molecules have been identified. By blending the first and second components consisting of two kinds of ethylene / α-olefin copolymers and two kinds of relatively low molecular weight ethylene-based polymers, melt elasticity, flow characteristics, and mechanical characteristics The present invention has been accomplished by finding that an ethylene / α-olefin copolymer composition having excellent mechanical properties, particularly at low temperature, and excellent processability can be obtained.

That is, the present invention provides (I) 5 to 85% by weight of a copolymer of ethylene and an α-olefin having 3 to 18 carbon atoms, which satisfies the following (a) to (d), and (a) an intrinsic viscosity ( η ₁ ) 2.0
~ 9.0 dl / g, (b) Density (d ₁ ) 0.890 to 0.935 g /
cm ³ , (c) Area I under the curve at an elution temperature of 90 ° C or higher in the elution temperature-elution amount curve by the continuous temperature elution fractionation method
The ratio S of the area Ib at the elution temperature of 25 to 90 ° C. to a
(Ib / Ia) is S ₁ or less calculated from the following equation, S ₁ = 20η ₁ ⁻¹ exp [−50 (d ₁ −0.900)] (d) 25 ° C. ortho-dichlorobenzene-soluble component W wt% is the following equation. W ₁ or more calculated from: W ₁ = 20exp (−η ₁ ), (II) Ethylene satisfying the following (e) to (h) and a carbon number of 3 to
18 to α-olefin copolymer 5 to 85% by weight,
(e) Intrinsic viscosity (η ₂ ) 1.6 to 7.0 dl / g, (f) Density (d ₂ ) 0.890 to 0.945 g / cm ³ , (g) Elution temperature by continuous temperature elution fractionation method -In the elution amount curve, the elution temperature is 25 with respect to the area Ia under the curve at the elution temperature of 90 ° C or higher.
The ratio S (Ib / Ia) of the area Ib at ˜90 ° C. is not more than S ₂ calculated from the following equation: S ₂ = 20 η ₂ ⁻¹ exp [−50 (d ₂ −0.900)] (h) 25 ° C. Chlorobenzene-soluble component W wt% is W ₂ or more calculated from the following formula, W ₂ = 20exp (−η ₂ ) (III) Ethylene homopolymer or ethylene and carbon number satisfying the following (i) and (j) 5 to 60% by weight of a copolymer of _{3 to} 18 with α-olefin, (i) intrinsic viscosity (η ₃ ) of 0.1.
2 dl / g~1.5dl / g, ( j) Density (d ₃₎ 0.890~0.
980 g / cm ³ , and (IV) 5-60% by weight of an ethylene homopolymer or a copolymer of ethylene and an α-olefin having 3 to 18 carbon atoms, which satisfies the following (k) and (l), (k) Intrinsic viscosity (η ₄ ) 0.2
dl / g to 1.5 dl / g, (l) density (d ₄ ) 0.890 to 0.9
80 g / cm ³ and has the above-mentioned components (I), (II), (II
The total of I) and (IV) is 100% by weight, and the components (I) to (IV) have different intrinsic viscosities from each other, and the intrinsic viscosity of the mixture is 0.7 to 6.0 dl / g,
Ethylene.α-having a density of 0.890 to 0.950 g / cm ³ and an N-value of 1.7 to 3.5 calculated from the following equation 2.
An olefin copolymer-based composition is provided. .

[0009]

[Equation 2]

The details of the present invention will be described below. The ethylene / α-olefin copolymer of the high molecular weight component or the medium molecular weight component of the first component and the second component of the present invention comprises a copolymer of ethylene and an α-olefin having 3 to 18 carbon atoms, and particularly carbon The number 4 to 10 are preferable from the viewpoint of mechanical properties. Specifically, 1-butene, 1-pentene, 1-
Hexene, 4-methyl-1-pentene, 1-octene,
Examples include 1-nonene and 1-decene. It should be noted that two or more α-olefins may be used in combination.

The ethylene / α-olefin copolymer as the first component (I) has (a) an intrinsic viscosity (η ₁ ) of 2.0 to
It is in the range of 9.0 dl / g, preferably 2.0 to 8.5 dl / g, more preferably 2.0 to 8.0 dl / g, and (b) the density (d ₁ ) is 0.890 to 0.8. It is in the range of 935 g / cm ³ , and preferably in the range of 0.890 to 0.930 g / cm ³ .

If the intrinsic viscosity (η ₁ ) is less than 2.0 dl / g, the melt elasticity and mechanical properties of the obtained composition are inferior, and if it exceeds 9.0 dl / g, the surface of the molded product is rough. Molding processability decreases, such as the generation of fish eyes. Further, those having a density (d ₁ ) of less than 0.890 g / cm ³ are not preferable because they are difficult to manufacture and cause stickiness of the obtained composition. On the other hand, when d ₁ exceeds 0.935 g / cm ³ , melt elasticity and mechanical properties deteriorate, which is not preferable.

The ethylene / α-olefin copolymer as the second component (II) has (e) an intrinsic viscosity (η ₂ ) of 1.6 to
7.0 dl / g, preferably 1.6 to 6.5 dl / g, more preferably 1.6 to 6.0 dl / g, and (f) density (d ₂ ).
Is in the range of 0.890 to 0.945 g / cm ³ , and preferably in the range of 0.890 to 0.940 g / cm ³ .

A high branching component containing many short chain branches dissolves in a solvent at a low temperature, but a low branching component containing few short chain branches does not dissolve in a solvent unless the temperature is high. It can be measured quantitatively. The components (I) and (II) used in the present invention are the same as those described above in (c) and (g), respectively.
As shown in Fig. 4, the continuous temperature elution fractionation method (Temperature Ris
ing Elution Fractionation (TREF) ； Journal of Polyme
rScience: Polymer Physics Edition, Vol.20, 441-45
5 (1982)), the area Ia under the curve at an elution temperature of 90 ° C. or more and the elution temperature of 25 to 9
It is necessary to establish a specific relationship with the same area Ib at 0 ° C. That is, the area ratio S shown in the schematic view of FIG.
= Ib / Ia has the following values in components (I) and (II):
It must be less than or equal to S ₁ and S ₂ obtained from the following equations, respectively. S ₁ = 20 η ₁ ^-1 exp [−50 (d ₁ −0.900)] S ₂ = 20 η ₂ ⁻¹ exp [−50 (d ₂ −0.900)] Branches when the value of S exceeds S ₁ or S _2. As a result of the distribution becoming almost uniform, the high branching component, which is extremely effective for melt elasticity and mechanical properties, particularly mechanical properties at low temperatures, is relatively decreased, which is not preferable.

The component (I) (d) and the component (II) (h) at 25 ° C. ortho-dichlorobenzene-soluble component used in the present invention are quantified by the continuous temperature-rising elution fractionation method because the elution temperature is too low. Since it is a component having a very high branch distribution to the extent that it cannot be performed, it must be a specific value or more. That is, the same soluble content W% by weight must be equal to or greater than W ₁ and W ₂ obtained from the following equations in the components (I) and (II), respectively. Preferably each W ₃
And W ₄ or more. _{W 1 = 20exp [-η 1]} , W 2 = 20exp [-η 2] W 3 = 22exp [-η 1], the W ₄ = 22exp [-η _2] the value of W is less than W ₁ or W _2, The highly-branched component, which is extremely effective for melt elasticity and mechanical properties, particularly mechanical properties at low temperature, becomes too small, which is not preferable as described above.

Component (III) which is a low molecular weight component of the present invention
Is an ethylene homopolymer or an ethylene / α-olefin copolymer. As the α-olefin used when ethylene / α-olefin is used, those having 3 to 18 carbon atoms are used as in the case of the components (I) and (II), preferably 4 to 10 carbon atoms, Especially 1 as above
-Butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-octene, 1-nonene, 1-decene and the like are preferable in terms of mechanical properties. It should be noted that two or more α-olefins may be used in combination.

(I) Intrinsic viscosity (η ₃ ) of the above component (III)
Is used in the range of 0.2 to 1.5 dl / g, and preferably in the range of 0.5.
It is in the range of 3 to 1.4 dl / g. When η ₃ is less than 0.2 dl / g, the mechanical properties of the obtained composition, especially at low temperature, are poor, while when it exceeds 1.5 dl / g, the flow properties are deteriorated. Not preferable.

The (j) density (d ₃ ) of the component (III) is 0.
Range is used 890~0.980g / cm ^3, preferably in the range of 0.900~0.975g / cm ^3. d ₃ is 0.8
If it is less than 90 g / cm ³ , it is not preferable because it is difficult to manufacture and causes stickiness of the obtained composition. On the other hand, when it exceeds 0.980 g / cm ³ , not only is it difficult to produce, but also the mechanical properties of the obtained composition deteriorate, which is also not preferable.

Component (IV) which is a low molecular weight component of the present invention
Is an ethylene homopolymer or an ethylene / α-olefin copolymer, and as the α-olefin when using the ethylene / α-olefin, it has 3 to 18 carbon atoms as in the case of the components (I) to (III). Those having 4 to 10 carbon atoms, especially 1-butene as described above,
1-Pentene, 1-hexene, 4-methyl-1-pentene, 1-octene, 1-nonene, 1-decene and the like are preferable in terms of mechanical properties and the like. The α-olefin is 2
It is possible to use more than one species together.

The intrinsic viscosity (η ₄ ) of component (IV) (k) used is in the range of 0.2 to 1.5 dl / g, preferably 0.3 to.
It is 1.4 dl / g, and more preferably 0.4 to 1.3 dl / g. When η ₄ is less than 0.2 dl / g, the mechanical properties of the obtained composition, particularly at low temperature, are poor, while on the other hand, 1.5 dl
If it exceeds / g, the flow properties will be deteriorated, and thus neither is preferable.

The component (IV) (l) density (d ₄ ) is 0.8.
Range is used 90~0.980g / cm ^3, preferably in the range of 0.900~0.970g / cm ^3. d ₄ is 0.8
If it is less than 90 g / cm ³ , the mechanical properties of the obtained composition are low, which is not preferable. On the other hand, when it exceeds 0.980 g / cm ³ , it is not preferable because the production is difficult.

Components (I), (II) and (II in the present invention
The mixing ratio of I) and (IV) is as follows: component (I) 5 to 85% by weight, component (II) 5 to 85% by weight, component (III) 5 to 60%.
% By weight and 5-60% by weight of component (IV), provided that the total amount of components (I), (II), (III) and (IV) is 1
It is 00% by weight, and these compounding amounts are selected depending on the performance required for the composition. Ingredient (I) or Ingredient (I
When the amount of I) is less than 5% by weight, melt elasticity and mechanical properties, particularly mechanical properties at low temperature, are not sufficient, while when it exceeds 85% by weight, flow properties become poor, so that neither can be used. However, it is essential that the intrinsic viscosities of the components (I) to (IV) are different from each other, and if this is not satisfied, it is difficult to improve the mechanical properties at low temperature which is one of the objects of the present invention. .

The ethylene / α-olefin copolymer type composition of the present invention comprises the components (I), (II),
It can be obtained by blending (III) and (IV), but the properties of the composition after blending must be within a specific range. That is, the intrinsic viscosity of the ethylene / α-olefin copolymer type composition is 0.7 to 6.0 dl / g, preferably 1 to 4 dl / g. When the intrinsic viscosity is less than 0.7 dl / g, the melt viscosity and mechanical properties, especially at low temperature, are insufficient, while when it exceeds 6.0 dl / g, the flow properties become poor, which are both preferable. Absent. The density of the ethylene / α-olefin copolymer composition of the present invention is 0.1.
890 to 0.950 g / cm ³ , preferably 0.900
Is a ~0.945g / cm ^3. When the density is less than 0.890 g / cm ^3, it is difficult to produce, and it causes stickiness of the composition, and when it exceeds 0.950 g / cm ³ , melt elasticity and mechanical properties are deteriorated. Further, the N-value of the ethylene / α-olefin copolymer composition needs to be 1.7 to 3.5, and preferably 1.7 to 3.0. N
-When the value is less than 1.7, the high-speed moldability is low, and when it is 3.5 or more, melt fracture tends to occur.

There is no particular limitation on the method for producing the ethylene / α-olefin copolymer composition of the present invention. For example, the components (I), (II), (III) and (IV) may be individually produced by one-step polymerization and then mixed by a known method, or two-step polymerization or more It may be produced by a known polymerization method by multistage polymerization and blended. When producing by the former mixing, a known method such as a method of kneading with a single-screw or twin-screw extruder or a Banbury mixer, or a solution mixing method can be used.

The latter method of multi-stage polymerization is to carry out two-stage or three-stage or more-stage polymerization using a plurality of reactors. For example, in the case of four-stage polymerization, the first and second stages are used. The reactors of the third stage are maintained under the polymerization conditions of the high molecular weight or medium molecular weight ethylene / α-olefin copolymers corresponding to the components (I) and (II), respectively, and the reactors of the third and fourth stages are treated as the components ( While maintaining the polymerization conditions of the low molecular weight polymers of III) and (IV), the polymer of the first stage is continuously passed through the second stage to the third and fourth stages to obtain ethylene / α-olefin. It can be carried out as in the case of producing a copolymer composition. In this case, the components (I), (II), (III) and (IV) may be produced in any reactor, and the production sequence and the number of stages are not particularly limited. The above-mentioned one-step or multi-step polymerization method is not particularly limited, and various methods such as a slurry method, a gas phase method, a solution method and a high pressure ion method can be used.

The polymerization catalyst is also not particularly limited, and for example,
Any of a Ziegler type catalyst mainly composed of a transition metal such as titanium and / or vanadium, a Phillips type catalyst mainly composed of a chromium-based catalyst, a Kaminsky type catalyst mainly composed of zirconium, a metallocene and the like can be used. Among the catalysts, a Ziegler type catalyst having a high activity, which is supported on a solid support, is particularly preferable, and the details thereof will be described below.

The highly active Ziegler type catalyst is an inorganic solid support such as magnesium metal, magnesium hydroxide, magnesium carbonate, magnesium oxide, various aluminas, silica, silica-alumina, magnesium chloride or the like, or magnesium and silicon, aluminum or calcium. Double salts, double oxides, hydrous carbonates, hydrous silicates, etc. containing selected elements, and further these inorganic solid carriers were treated or reacted with oxygen-containing compounds, sulfur-containing compounds, hydrocarbons, halogen-containing substances. For inorganic solid carriers such as
A transition metal compound, for example, a metal halide such as titanium, vanadium, zirconium, or chromium loaded with an alkoxy halide, an oxide, or a halogenated oxide is used as a solid component. A combination of organic compounds, preferably zinc or aluminum organometallic compounds, or these
-Such as those pre-treated by contacting with olefins,
Usually, the catalyst activity is 50 g-polymer / g-catalyst · hr · kg / cm ² -olefin pressure or more, preferably 100 g-polymer / g-catalyst · hr · kg / cm ² -olefin pressure or more.

The ethylene / α-olefin copolymer composition of the present invention comprises other olefin polymers, rubbers, etc., antioxidants, ultraviolet absorbers, light stabilizers, etc. within the scope of the present invention. Known additives such as a lubricant, an antistatic agent, an antifogging agent, an antiblocking agent, a processing aid, a coloring pigment, a cross-linking agent, a foaming agent, an inorganic / organic filler, and a flame retardant can be blended and used.

[0029]

EXAMPLES The present invention is described in detail below with reference to examples, but the present invention is not limited thereto. First, the test method used in the present invention will be described. (1) Intrinsic viscosity Intrinsic viscosity [η] was measured with a 135 ° C decalin solution. (2) Density Density gradient tube method (23
(° C). (3) Continuous temperature rising elution fractionation method (TREF) As described above, the method of L. Wild et al. Was followed. The details of the measuring method are as follows. [Measurement Method] 5 ml of an orthodichlorobenzene solution prepared by heating and dissolving the sample at 135 ° C. to a concentration of 0.05% by weight was injected into a 8.5 liter stainless steel column filled with Celite 545. After 4 ℃ / min
The sample is deposited on the surface of Celite by cooling to 25 ° C at a cooling rate of. Next, while ortho-dichlorobenzene is flown through this column at a constant rate of 1 ml / min, the temperature is raised at a constant rate of 50 ° C./hr to elute the samples sequentially. At this time, with respect to the sample eluted in the solvent, the absorption at a wave number of 2925 cm ⁻¹ of the asymmetric stretching vibration of methylene was detected by an infrared detector,
By recording, the relationship between the elution temperature and the elution amount, that is, the composition distribution is obtained. (4) Area ratio S by continuous temperature rising elution fractionation method Calculated and calculated as described above and in FIG. (5) 0.5 g of the ortho-dichlorobenzene-soluble matter W at 25 ° C. was added to 20 ml of ortho-dichlorobenzene (O).
In DCB), heat at 135 ° C. for 2 hours to completely dissolve the sample and then cool to 25 ° C. in 2 hours. After leaving this solution at room temperature 25 ° C. overnight, it was filtered with a Teflon filter to collect the filtrate, and the absorption of methylene asymmetric stretching vibration at a wave number of 2950 cm ⁻¹ was measured with an infrared spectrophotometer. The sample concentration in the filtrate is quantified by the calibration curve prepared. (6) N-value Higher flow tester (manufactured by Shimadzu Corporation) is used.
Extruded from a 2mmφ × 40mm die at a resin temperature of 170 ℃, low test pressure 20kg / cm ² and high test pressure 15
The apparent shear rate at 0 kg / cm ² is calculated and calculated by the following equation 3.

[Equation 3] (7) Melt flow rate (MFR) Measured according to JIS K6760. (Measurement temperature: 190 ° C., load: 2.16 kg) (8) High load melt flow rate (HLMFR) Measured in accordance with JIS K6760. (Measurement temperature 1
90 ° C, load 21.6 kg) (9) Flow parameter (FP) FP is a calculated value obtained from the following equation. FP = log (HLMFR / MFR) (10) Tensile yield strength (YTS) Measured according to JIS K6760. (Tensile speed 50 mm / min, test piece thickness 2 mm) (11) Tensile impact value (TIS) Measured in accordance with ASTM D1822. (Test piece thickness 1.5 mm) (12) Izod impact value (IIS) Based on JIS K7110, measured at 23 ° C and -40 ° C by the following method. 2 by pressing from sample
A sheet having a thickness of 3 mm when measured at 3 ° C and a thickness of 4 mm when measured at -40 ° C was prepared, and the shape of the test piece was designated as No. 2A. The sample was adjusted at 23 ° C. and 50% humidity for 88 hours and measured at 23 ° C. and −40 ° C. However, −
The sample to be measured at 40 ° C. was adjusted under the above conditions and then held in a low temperature chamber whose temperature was previously adjusted to −40 ° C. for about 3 hours and measured in the low temperature chamber. Five test pieces were prepared, and the average value of five measurements was used as the measurement value. (13) Bending stiffness Measured in accordance with JIS K7106. (Toyo Seiki
Bending stiffness tester manufactured by Co., Ltd. is used.) (14) Melt tension (MT) Measured by a melt tension tester manufactured by Toyo Seiki Co., Ltd. (Measurement temperature 190 ° C.) (15) Critical shear rate (γc) It was measured by a capillary rheometer manufactured by INTESCO. (Measurement temperature: 190 ° C.) (16) Melting point (Tm) The maximum peak temperature measured using a differential scanning calorimeter manufactured by Rigaku Denki Co., Ltd. was used. (Preparation of test piece from 0.2 mm thick pressed sheet) (17) Environmental stress crack resistance (ESCR) Constant strain ESCR F according to JIS K6760
A value of ₅₀ was measured.

<Production Example by Two-Stage Polymerization> In the multi-stage polymerization process shown in FIG. 2, a stirring reactor having an internal volume of 30 liters is used as the first-stage reactor 1, and a solid containing anhydrous magnesium chloride as one component. A solid catalyst supporting titanium tetrachloride on a carrier was supplied from a line 2 and triethylaluminum (TEA) was supplied as a co-catalyst from a line 3 to continuously polymerize ethylene and a comonomer under the polymerization conditions shown in Table 1. I went. In the figure, reference numeral 4 is an ethylene supply line, 5 is a comonomer supply line, 6 is a hydrogen supply line, and 7 is a solvent supply line. By changing the type of α-olefin and the polymerization conditions, two-stage polymerization
A polymer of A11 was produced. The polymerization conditions are shown in Table 1 and Table 2.
The results of evaluation of physical properties are shown in Tables 3 and 4.

Next, a production example of the polymer A5 will be specifically described. The polymerization conditions for the first stage reactor 1 are a polymerization temperature of 5
At 5 ° C., the total pressure was 8.2 kg / cm ² G, and the reactor 1 was kept full of liquid. Polymer yield E1 calculated from heat balance is 1.68k
It was g / hr. A part of the polymerization product of the first-stage reactor was sampled, and the polymer was collected to measure the physical properties. Then, the slurry-like polymerization product from the first-stage reactor was introduced into the second-stage stirred reactor 9 having an internal volume of 70 liters by a differential pressure via the line 8. Ethylene, 1-butene and hydrogen were added as shown in Table 1, the polymerization temperature was 60 ° C., the total pressure was 8.0 kg / cm ² G,
The polymerization was continued while maintaining the liquid volume at 50 liters. The polymerization product discharged from the second stage reactor 9 was then introduced into the flushing tank 10 via a line 11. The polymer production amount E2 calculated from the heat balance was 1.68 kg / hr. The polymerized product was continuously extracted from the line 12 to collect the polymerized product, and its physical properties were evaluated. The amount E of the polymer product finally recovered is 3.
It was 36 kg / hr, which was in agreement with the calculated value of E1 + E2. The average polymerization times of the first-stage reactor 1 and the second-stage reactor 9 were 25 minutes and 40 minutes, respectively.

[0032]

[Table 1]

[0033]

[Table 2]

[0034]

[Table 3]

[0035]

[Table 4]

<Production Example by One-Stage Polymerization> In the one-stage polymerization process shown in FIG. 3, titanium tetrachloride is supported on a solid carrier containing anhydrous magnesium chloride as one component by using a stirring type reactor having an internal volume of 70 liters. Using the solid catalyst thus prepared and a triethylaluminum cocatalyst, one-stage polymerization was continuously carried out under the polymerization conditions shown in Table 5 to produce a low molecular weight component (B1). In addition, high molecular weight components (B2 ~
B5) was produced. The results of evaluating the physical properties of these polymers are shown in Table 5.

[0037]

[Table 5]

Next, the polymer obtained by the above one-stage polymerization is
Using a plastomill, under nitrogen atmosphere, sample load 70 g, rotation speed 20 rpm, kneading time 7 minutes, kneading temperature 1
Blending was performed under a blending condition of 60 ° C. to prepare a blend composition. The blending ratio and physical properties are shown in Table 6.

[0039]

[Table 6]

<Examples 1 to 7> A blend composition comprising the polymerization products obtained by the two-step polymerization shown in Tables 3 and 4 and the one-step polymerization blended product shown in Table 6 was prepared in the proportions shown in Table 7. A composition consisting of four components was prepared by blending. Table 8 shows the results of evaluating the physical properties of the obtained composition.

[0041]

[Table 7]

[0042]

[Table 8]

<Comparative Examples 1 to 6> A blend composition comprising the polymerization products obtained by the two-stage polymerization shown in Tables 3 and 4 and the one-stage polymerization blended product shown in Table 6 in the proportions shown in Table 9 was prepared. A composition consisting of four components was prepared by blending. The results of evaluating the physical properties of the composition are shown in Table 10.

[0044]

[Table 9]

[0045]

[Table 10]

<Comparative Examples 7 to 13> Tables 11 and 12 show the results of evaluation of commercially available linear low density polyethylene of the following brands. (1) Philips # 10 (manufactured by Philips) (2) NUC G5221 (manufactured by Nippon Unicar) (3) Moretech 0234H (manufactured by Idemitsu Kasei) (4) DSM 1016 (manufactured by DSM) (5) CdF FW1290 (CdF) (Made by Mitsui Petrochemical Co., Ltd.) (6) Dow XD6000 8-130 (Made by Dow Chemical) (7) Ultex 2520L

[0047]

[Table 11]

[0048]

[Table 12]

As shown in the comparative examples of Table 11 and Table 12, all of the commercially available linear low density polyethylenes have TRE.
At least one of the area ratio S by F and the ortho-dichlorobenzene-soluble component W at 25 ° C. cannot satisfy the requirements of the present invention. Therefore, these linear low density polyethylenes cannot be used as the component (I) or the component (II) of the present invention.

Next, FIG. 4 shows a schematic diagram in which the molecular weight is further added as a parameter to the elution temperature-elution amount curve by TREF shown in FIG. 1 and the elution amount is represented by contour lines.
When the example and the comparative example are compared in the figure, the composition of the example has a larger molecular weight (about 1%) than that of the comparative example.
(More than 20,000) and low elution temperature, that is, components with many short-chain branches (soluble components in orthodichlorobenzene at 25 ° C)
It can be seen that it contains more. It is speculated that this component is the main factor for improving the mechanical properties of the composition of the present invention at low temperatures.

[0051]

The ethylene / α-olefin copolymer composition of the present invention has the following characteristics in addition to the physical properties such as heat resistance, ESCR and flexibility of the conventional polyethylene composition. (1) Excellent mechanical properties at low temperature such as low temperature Izod impact value and cold resistance. (2) Good mechanical properties such as tensile properties, bending stiffness, environmental stress crack resistance, and creep resistance. (3) Since it has excellent melt elasticity such as melt tension and excellent flow characteristics such as critical shear rate, it has good moldability such as high-speed moldability. As a result of having the above-mentioned advantages, it is used for various films, sheets, pipes, hollow containers, various coating materials, foam materials and the like. Further, since it can be suitably used for all molding methods such as extrusion molding, blow molding, and injection molding, it has become clear that a wide range of molded products can be obtained.

[Brief description of drawings]

FIG. 1 is a schematic diagram of an area ratio S in an elution temperature-elution amount curve by a continuous temperature rising elution fractionation method (TREF).

FIG. 2 is a flow schematic diagram of a multi-stage polymerization process used in Examples of the present invention.

FIG. 3 is a schematic flow diagram of a one-step polymerization process used in Examples of the present invention.

FIG. 4 is a contour map of elution temperature-molecular weight-elution amount of a composition. (A) Example 6, (b) Comparative Example 1

[Explanation of symbols]

 1 First Stage Reactor 2 Catalyst Supply Line 3 Organometallic Compound Supply Line 4 Ethylene Supply Line 5 Comonomer Supply Line 6 Hydrogen Supply Line 7 Polymerization Solvent Supply Line 8 First Stage Polymerization Product Transfer Line 9 Second Stage Reactor 10 Flushing Tank 11 Second stage polymerization product transfer line 12 Polymer recovery line

Claims (1)

[Claims] 1. (I) A copolymer of ethylene and an α-olefin having 3 to 18 carbon atoms which satisfies the following (a) to (d):
85% by weight, (a) intrinsic viscosity (η ₁ ) 2.0 to 9.0 dl / g, (b) density (d ₁ ) 0.890 to 0.935 g / cm ³ , (c) continuous temperature rising elution fractionation In the elution temperature-elution amount curve by the method, the ratio S (Ib / of the area Ib at the elution temperature of 25 to 90 ° C. to the area Ia under the curve at the elution temperature of 90 ° C. or more
Ia) is less than or equal to S ₁ calculated from the following equation: S ₁ = 20η ₁ ⁻¹ exp [−50 (d ₁ −0.900)] (d) 25 ° C. ortho-dichlorobenzene soluble content W weight% is calculated from the following equation. W ₁ or more, W ₁ = 20exp (−η ₁ ), (II) Ethylene satisfying the following (e) to (h) and a carbon number of 3 to
18-α-olefin copolymer 5 to 85% by weight, (e) intrinsic viscosity (η ₂ ) 1.6 to 7.0 dl / g, (f) density (d ₂ ) 0.890 to 0.945 g / cm ³ , (g) In the elution temperature-elution amount curve by the continuous temperature elution fractionation method, the ratio S (Ib / of the area Ib at the elution temperature of 25 to 90 ° C to the area Ia under the curve at the elution temperature of 90 ° C or more)
Ia) is less than or equal to S ₂ calculated from the following equation, S ₂ = 20η ₂ ⁻¹ exp [−50 (d ₂ −0.900)] (h) 25 ° C. ortho-dichlorobenzene soluble content W weight% is calculated from the following equation. W ₂ or more, W ₂ = 20exp (−η ₂ ) (III) An ethylene homopolymer or a copolymer of ethylene and an α-olefin having 3 to 18 carbon atoms which satisfies the following (i) and (j): To 60% by weight, (i) intrinsic viscosity (η ₃ ) 0.2 dl / g to 1.5 dl / g, (j) density (d ₃ ) 0.890 to 0.980 g / cm ³ , and (IV) 5 to 60% by weight of an ethylene homopolymer or a copolymer of ethylene and an α-olefin having 3 to 18 carbon atoms, which satisfies the following (k) and (l), (k) intrinsic viscosity (η ₄ ) 0.2 dl / g to 1.5 dl / g, (l) Density (d ₄ ) of 0.890 to 0.980 g / cm ³ and containing the components (I), (II), (III) and (IV) The total is 100% by weight, each Ingredient (I) ~
(IV) a mixture having different intrinsic viscosities from each other, wherein the intrinsic viscosity of the mixture is 0.7 to 6.0 dl / g, the density is 0.890 to 0.950 g / cm ³ and the following equation 1 is calculated. The ethylene / α-olefin copolymer composition having an N-value of 1.7 to 3.5. [Equation 1]