JPH06248127A - Polyethylene resin composition - Google Patents

Abstract

PURPOSE:To obtain a polyethylene resin compsn. excellent esp. in melting and optical charactristics and suitable for a large-size hollow molding by compounding three specific ethylene homopolymers or ethylene-alpha-olefin copolymers. CONSTITUTION:This resin compsn. has an intrinsic viscosity of 1.0-6.0dl/g, a density of 0.890-0.970g/cm<3>, and an N-value obtd. by forula III of 1.117-3.0 and comprises 1-50% ultrahigh-mol.-wt. ethylene homopolymer or ethylene-alpha- olefin copolymer having an intrinsic viscosity eta1 and a density d1 each in a specified range, 5-94% ethylene (co)polymer having an intrinsic viscosity eta2 and a density d2 each in a specified range, a ratio S [i.e., a ratio (Ib/Ia) of the area Ib under the elution temp.-elution amt. curve obtd. by temperature rising elution fractionation between the dissolution temps. of 25 deg.C and 90 deg.C to the area Ia under the cure in the range of the elution temp. of 90 deg.C or higher] not higher than S1 obtd. from formula I, and a content of o- dichlorobenzene solubles (W wt.%) at 25 deg.C not higher than W1 obtd. by formula II, and 5-50% ethylene (co)polymer obtd. by high-pressure free-radical polymn.

Description

Detailed Description of the Invention

[0001]

INDUSTRIAL APPLICABILITY The present invention is excellent in melt elasticity (melt tension, die swell ratio, etc.), flow characteristics (processing characteristics, etc.), mechanical characteristics (impact resistance, tensile strength, etc.), and has an extremely high molecular weight distribution. With respect to a wide ethylene polymer composition,
Particularly, it relates to an ethylene polymer composition which is excellent in optical properties and mechanical properties at low temperature, and has a large melt tension and die swell ratio, and is suitable for large hollow molded products such as gasoline tanks and extrusion molded products such as large diameter pipes. .

[0002]

2. Description of the Related Art Heretofore, a method of broadening the molecular weight distribution of an ethylene / α-olefin copolymer has been reported for the purpose of improving flow characteristics (for example, JP-A-57-21409 and JP-B-63-47741). However, if the molecular weight distribution is simply widened as described in the report, melt elasticity and mechanical properties, particularly mechanical properties at low temperature, are not improved, but rather greatly reduced. In addition, regarding the improvement of mechanical properties and flow properties, the short chain branching degree of the high molecular weight component of the ethylene / α-olefin copolymer consisting of the high molecular weight component and the low molecular weight component was specified and Attempts have been made to improve not only mechanical properties and fluidity but also environmental stress crack resistance (ESCR) by introducing many branches (Japanese Patent Laid-Open No. 54-10044 and Japanese Patent Publication No. 64-7096). ). However, even with these improvements, the mechanical properties, especially at low temperatures, and the melt elasticity are not satisfactory. Furthermore, JP-A-2-305
Japanese Patent No. 811 proposes a method of specifying a catalyst and polymerization conditions for two-step polymerization for the purpose of improving impact resistance, ESCR, and pinch-off fusion bondability.
Although there is some improvement in ESCR and melt elasticity, it is insufficient to improve mechanical properties, especially at low temperatures. In addition, a polyethylene composition for blow molding, which has improved drawdown resistance, die swell and ESCR (JP-A-59-89341 and JP-A-60).
No. 20946, etc.) and a three-stage polymerization method has been proposed as a method for improving the drawbacks of the two-stage polymerization method (Japanese Patent Publication No. 59-10724 and Japanese Patent Application Laid-Open No. 62-25105).
No. 62-25106, No. 62-25107, No. 62-25108, No. 62-25109, etc.).
Also in these proposals, the improvement of the melt elasticity and the flow characteristics is still insufficient, and in particular, the optical characteristics and the mechanical characteristics at low temperature are not improved.

[0003]

In view of the above points, the present invention has melt elasticity (melt tension, die swell ratio, etc.), flow characteristics (processing characteristics, etc.), mechanical characteristics (impact resistance,
It is an ethylene polymer composition with an excellent balance of various physical properties such as tensile strength, etc., and an extremely wide molecular weight distribution. In particular, it has excellent optical properties and mechanical properties at low temperatures, and has a large melt tension and die swell ratio. It is an object of the present invention to provide a composition suitable for a large hollow molded product such as a gasoline tank and an extrusion molded product such as a large diameter pipe.

[0004]

Means for Solving the Problems As a result of intensive studies conducted by the present inventors in view of the above objects, a specific ethylene / α-olefin copolymer having an extremely high molecular weight component and an extremely wide short-chain branch distribution between molecules has been obtained. Alternatively, by blending three components consisting of an ethylene homopolymer and an ethylene (co) polymer obtained by high-pressure radical polymerization, excellent balance of various physical properties such as melt elasticity, flow characteristics, mechanical characteristics, etc., particularly optical characteristics and low temperature The present invention has been accomplished by finding that an ethylene polymer composition having excellent mechanical properties at the time is obtained. That is, the present invention comprises (I) 1 to 50% by weight of an ultrahigh molecular weight ethylene homopolymer or ethylene / α-olefin copolymer satisfying the following conditions (a) and (b), and (a) an intrinsic viscosity (η ₁ ) 9 to 45 dl / g, (b) density (d ₁ ) 0.890
0.935 g / cm ³ , (II) Ethylene homopolymer or ethylene / α-olefin copolymer 5 to 94 satisfying the following conditions (c) to (f):
% By weight, (c) intrinsic viscosity (η ₂ ) 0.3 to 3.0 dl / g, (d)
Density (d ₂ ) 0.890 to 0.980 g / cm ³ , (e) In the elution temperature-elution amount curve by the continuous temperature elution fractionation method, the elution temperature 2 for the area Ia under the curve at the elution temperature of 90 ° C. or higher
The ratio S (Ib / Ia) of the area Ib under the curve of 5 to 90 ° C. is S ₁ or less calculated from the following equation, S ₁ = 20η ₂ ⁻¹ exp [−50 (d ₂ −0.900)] (f) 25% ortho-dichlorobenzene soluble content W% by weight is W ₁ or less calculated from the following formula, W ₁ = 100 η ₂ ^-0.5 exp [−50 η ₂ ^0.5 (d ₂ −0.900)], and (III) by high pressure radical polymerization 5 to 50% by weight of an ethylene (co) polymer, and the components (I) and (II)
The total of (III) and (III) is 100% by weight, and the components (I) to (III) have different intrinsic viscosities, and the intrinsic viscosity of the mixture is 1.0 to 6.0 dl /
It is intended to provide an ethylene polymer composition having g, a density of 0.890 to 0.970 g / cm ³ and an N-value of 1.7 to 3.0 calculated from the following equation.

[0005]

[Equation 2]

The details of the present invention will be described below. The ultrahigh molecular weight component (I) of the present invention is an ethylene homopolymer or an ethylene / α-olefin copolymer, and the α-olefin of the copolymer has a carbon number of 3-18. Particularly, those having 4 to 10 carbon atoms are preferable from the viewpoint of mechanical properties. Specifically, 1-butene, 1-pentene,
1-hexene, 4-methyl-1-pentene, 1-octene, 1-nonene, 1-decene and the like can be mentioned. Α-
Two or more olefins may be used in combination without any problem.

The above-mentioned ultrahigh molecular weight component (I), an ethylene homopolymer or an ethylene / α-olefin copolymer, is
(a) Intrinsic viscosity (η ₁ ) is 9 to 45 dl / g, preferably 10
It is preferably 40 dl / g, more preferably 12 to 40 dl / g. When η ₁ is less than 9 dl / g, the melt elasticity and mechanical properties of the obtained composition are poor, and when it is more than 45 dl / g, the molding processability is deteriorated, such as the surface roughness of the molded product and fish eyes. . The components (I) (b) Density (d ₁₎ is in the range of 0.890~0.935g / cm ^3, preferably is used in the range of 0.890~0.930g / cm ^3. If d ₁ is less than 0.890 g / cm ³ , it is not preferable because it is difficult to produce and the resulting composition becomes sticky. On the other hand, when d ₁ exceeds 0.935 g / cm ³ , the mechanical properties of the composition, particularly at low temperature, are deteriorated, which is not preferable.

The component (II) of the present invention is an ethylene homopolymer or an ethylene / α-olefin copolymer. As the α-olefin of the ethylene / α-olefin copolymer, those having 3 to 18 carbon atoms are used as in the case of the component (I), preferably 4 to 10 carbon atoms, and particularly 1- 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 and the like. It should be noted that two or more α-olefins may be used in combination.

The intrinsic viscosity (η ₂ ) of component (II) (c) is in the range of 0.3 to 3.0 dl / g, preferably 0.6 to 3.0.
It is in the range of 0 dl / g. When η ₂ is less than 0.3 dl / g, the mechanical properties of the obtained composition, particularly at low temperature, are poor, and when it exceeds 3.0 dl / g, the flow properties are deteriorated, and therefore, in any case. Not preferable. The components (II) (d) Density (d ₂₎ is in the range of 0.890~0.980g / cm ^3, preferably is used in the range of 0.900~0.975g / cm ^3. Those having d ₂ of less than 0.890 g / cm ³ are not preferable because they are difficult to produce and cause stickiness of the obtained composition. On the other hand, when it exceeds 0.980 g / cm ³ ,
Not only is it difficult to manufacture, but also the mechanical properties of the resulting composition deteriorate, which is likewise undesirable.

The above condition (e) relating to the component (II) used in the present invention is that the high branching component containing many short chain branches dissolves in the solvent at low temperature, but the low branching component containing few short chain branches is The branch distribution is quantitatively defined by utilizing the property that it does not dissolve in a solvent unless the temperature is high. That is, L. Wild et al.'S continuous temperature rising elution fractionation method (Temperature Rising Elution Fractiona)
tion (TREF); Journal of Polymer Science: Polymer
Physics Edition, Vol.20, 441-455 (1982)), in the elution temperature-elution amount curve, the area Ia under the curve at an elution temperature of 90 ° C or higher and the area I under the curve at an elution temperature of 25 to 90 ° C.
It is necessary to establish a specific relationship with b, and in the present invention, the area ratio S = Ib shown in the schematic view of FIG.
The value of / Ia must be less than or equal to S ₁ obtained from the following equation. S ₁ = 20 η ₂ ^-1 exp [−50 (d ₂ −0.900)] When the value of S exceeds S ₁ , the branch distribution becomes almost uniform, resulting in mechanical characteristics, especially at low temperature. The extremely effective high branching component is relatively decreased, which is not preferable.

Component (II) (f) 25 ° C. used in the present invention
The ortho-dichlorobenzene-soluble content is so low that the elution temperature is too low to be quantified by the continuous temperature-rising elution fractionation method described above.
It represents the amount of a component having an extremely large amount of branching, and needs to be a specific value corresponding to the intrinsic viscosity and the density. However, this also indicates the presence of a non-useful low molecular weight component, which should be eliminated as much as possible. For this purpose, the same soluble content W% by weight must be W ₁ or less obtained from the following equation. It is preferably W ₃ or less. W ₁ = 100 η ₂ ^-0.5 exp [−50 η ₂ ^0.5 (d ₂ −0.900)] W ₃ = 90 η ₂ ^−0.5 exp [−50 η ₂ ^0.5 (d ₂ −0.900)] When the value of W is W ₁ or more, it is extremely high. It shows that in addition to the components having a large amount of branching, there is a non-useful low-molecular weight component, resulting in poor mechanical properties, especially at low temperatures.

The ethylene (co) polymer by the high pressure radical polymerization of the component (III) of the present invention means low density polyethylene; ethylene-vinyl ester copolymer such as ethylene-vinyl acetate copolymer; ethylene-methacrylic acid copolymer. Ethylene-α, β-unsaturated carboxylic acid copolymers such as polymers, ethylene-acrylic acid copolymers, ethylene-maleic anhydride copolymers; ethylene-methyl methacrylate copolymers, ethylene-methyl acrylate copolymers Polymer, ethylene
Examples thereof include ethylene-α, β-unsaturated carboxylic acid ester copolymers such as ethyl methacrylate copolymer, ethylene-ethyl acrylate copolymer, ethylene-glycidyl methacrylate copolymer and the like. Among these, low density polyethylene, ethylene-vinyl acetate copolymer, ethylene-ethyl acrylate copolymer and the like are preferable.

The melt flow (MFR) of the ethylene (co) polymer by the high pressure radical polymerization of the component (III) is 0.
The amount is 05 to 100 g / 10 minutes, preferably 0.1 to 50 g / 10 minutes. When low density polyethylene is used as the component (III), its density is in the range of 0.91 to 0.94 g / cm ³ , preferably 0.91 to 0.935 g / cm ³ . In addition, the component (I
When an ethylene-vinyl acetate copolymer is used as II), the content of vinyl acetate is 1 to 40% by weight, preferably 3%.
~ 30% by weight. Also in the case of ethylene-ethyl acrylate copolymer, the content of ethyl acrylate is 1 to 40% by weight, preferably 3 to 30% by weight.

The proportions of the components (I), (II) and (III) in the present invention are 1 to 50% by weight of the component (I), 5 to 94% by weight of the component (II) and 5 to 50% of the component (III). % By weight, preferably (I) 5-40% by weight,
(II) 5 to 90% by weight and (III) 5 to 40% by weight, provided that the total amount of the components (I), (II) and (III) is 100% by weight, depending on the performance required for the composition. These compounding ratios are selected. Among the above components, since the component (I) plays an important role in the present invention, it is preferable to select the blending ratio of the composition in consideration of the characteristics of the component (I). When the amount of the component (I) is less than 1% by weight, melt elasticity and mechanical properties, particularly mechanical properties at low temperature, are insufficient, while when it exceeds 50% by weight, the flow properties become poor. It is important that the intrinsic viscosities of the components (I) to (III) are different from each other, and if this is not satisfied, the flow characteristics, which is one of the objects of the present invention, cannot be improved.

The ethylene polymer composition of the present invention is obtained by blending the components (I), (II) and (III) as described above, and the composition has an intrinsic viscosity of 1.0 to 6.0 dl / g,
It is preferably 1.5 to 5.0 dl / g. Intrinsic viscosity 1.0d
If it is less than 1 / g, the melt viscosity and mechanical properties, especially at low temperature, are insufficient, while if it exceeds 6.0 dl / g, the flow properties are poor, so neither is preferable. Density of the composition is 0.890~0.970g / cm ^3, preferably 0.900~0.970g / cm ^3.
If the density is less than 0.890 g / cm ^3, it is difficult to produce and the composition becomes sticky, and if it exceeds 0.970 g / cm ³ , the mechanical properties are low. Further, it is necessary that the N-value of the composition is 1.7 to 3.0, and preferably 1.7 to 2.8. When the N-value is less than 1.7, the high speed moldability is low, and when it exceeds 3.0, melt fracture tends to occur.

The method for producing the ethylene polymer composition of the present invention is not particularly limited. For example, after the components (I), (II) and (III) are each independently produced by one-step polymerization, they may be mixed by a known method, or by two-step or more multi-step polymerization, It may be produced by a known polymerization method. In the case of 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 by multi-stage polymerization is one in which the polymerization is carried out using a plurality of reactors. For example, in the case of two-stage polymerization, the first stage reactor is charged with the component (I). An ethylene polymer composition is prepared by maintaining the polymerization conditions for production, maintaining the second stage reactor under the polymerization conditions of component (II), and continuously flowing the polymer produced in the first stage to the second stage. Can be manufactured. In this case, the components (I) and (II) may be produced in any reactor,
The number of stages is not particularly limited. In any of the above cases, the reaction form is not particularly limited, and the slurry method,
Various polymerization methods such as 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 containing a transition metal such as titanium and / or vanadium, a Phillips type catalyst mainly containing a chromium catalyst, a Kaminsky type catalyst mainly containing a metallocene and the like can be used. Among the catalysts, particularly preferred is a Ziegler-type catalyst having a high activity, which is supported on a solid support, 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 containing selected elements, double oxides, hydrous carbonates, hydrous silicates, etc., and further these inorganic solid carriers are treated or reacted with oxygen-containing compounds, sulfur-containing compounds, hydrocarbons, halogen-containing substances. As a solid component, an inorganic solid carrier such as a metal oxide, a transition metal compound, for example, a metal halide such as titanium, vanadium, zirconium, or chromium supported thereon, an alkoxy halide, an oxide, or a halogenated oxide is used. An organic compound of a Group I-IV metal, preferably Combinations of lead or organometallic compounds of aluminum, or these further α-
Pretreated by contacting with olefin, etc., and usually has a catalytic activity of 50 g-polymer / g-catalyst · hr · kg / cm ² -olefin pressure or more, preferably 100 g-polymer / g-catalyst · h
r · kg / cm ² -Olefin pressure or higher. Among the above, a highly active Ziegler type catalyst containing magnesium halide is particularly preferable.

In the ethylene polymer composition of the present invention, other olefinic polymers, rubbers or the like or antioxidants, ultraviolet absorbers, light stabilizers, lubricants, antistatic agents are included within the scope of the present invention. Well-known additives such as anti-fog agents, anti-blocking agents, processing aids, color pigments, cross-linking agents, foaming agents, inorganic / organic fillers, flame retardants and the like can be blended and used.

[0021]

EXAMPLES The present invention will now be described in detail with reference to examples, but the present invention is not limited thereto. First,
The test methods used in the present invention are shown. (1) Intrinsic viscosity [η] Measured in a 135 ° C decalin solution. (2) Density Density gradient tube method (23
℃). (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. Volume filled with Celite 545 8.
After injecting 5 ml of an orthodichlorobenzene solution prepared by heating and dissolving the sample at 135 ° C. to a concentration of 0.05% by weight into a 5 liter stainless steel column,
Cool to 25 ° C at a cooling rate of 4 ° C / min to deposit the sample on the Celite surface. Next, while flowing ortho-dichlorobenzene through this column at a constant rate of 1 ml / min, 50 ° C / hr.
The temperature is raised at a constant rate, and the samples are sequentially eluted. 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 is detected by an infrared detector and recorded to obtain the relationship between the elution temperature and the elution amount, that is, the composition distribution. (4) Area ratio (S) by continuous temperature rising elution fractionation method As described above and in FIG. (5) Orthodichlorobenzene soluble content (W) at 25 ° C. 0.5 g of a sample was added to 20 ml of orthodichlorobenzene (ODC).
In B), 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 overnight at 25 ° C., it was filtered with a Teflon filter to collect the filtrate, and the absorption of the asymmetric stretching vibration of methylene at a wave number of 2950 cm ⁻¹ was measured with an infrared spectrophotometer.
From this result, the concentration of the sample in the filtrate is quantified by a calibration curve prepared in advance. (6) N-value Extruded from a die of 2 mmφ × 40 mm at a resin temperature of 210 ° C. using a high flow tester (manufactured by Shimadzu Corporation) and apparently at a low test pressure of 20 kg / cm ² and a high test pressure of 150 kg / cm ^2. The shear rate of is calculated and calculated by the following equation 3.

[Equation 3] (7) High load melt flow rate (HLMFR) Measured in accordance with JIS K6760. (Measurement temperature 190
(° C, load 21.6 kg) (8) Tensile yield strength (YTS) According to JIS K6760. (Pulling speed 50mm / mi
n, test piece thickness 2 mm) (9) Tensile impact value (TIS) Measured in accordance with ASTM D1822. (Test piece thickness 1.
5 mm) (10) Izod impact value (IIS) Based on JIS K7110, measured at -40 ° C by the following method. A sheet having a thickness of 3 mm is produced from the sample by pressing. The shape of the test piece is No. 2A. After adjusting the sample at 23 ° C and 50% humidity for 88 hours,
After the temperature is kept at -40 ° C for about 3 hours in the low temperature chamber, the temperature is measured at -40 ° C in the low temperature chamber. Five test pieces are prepared, and the average value of five measurements is used. (11) Melt tension (MT) Measured with a melt tension tester manufactured by Toyo Seiki Co., Ltd. (Measurement temperature: 190 ° C.) (12) Die swell ratio (DSR) A sample is extruded at a temperature of 210 ° C. using a high-performance flow tester, and the ratio between the strand diameter and the die inner diameter is determined. The shear rate is measured at an extrusion rate corresponding to 100 sec ^-1 . (13) Critical shear rate (γc) Measured with a capillary rheometer manufactured by INTESCO. (Measurement temperature 190 ° C.) (14) Environmental stress crack resistance (ESCR) The value of F ₅₀ of constant strain ESCR according to JIS K6760 is obtained. (15) Haze (% haze) A sheet having a thickness of 50 μm was prepared from a sample by pressing (cooling rate 40 ° C./min), and a direct reading haze computer (trade name: HGH-2D according to JIS K7105 was specified.
P, manufactured by Suga Test Instruments Co., Ltd.).

[Production of Components (I) and (II)] First,
Using a stirred reactor with an internal volume of 50 liters, a solid catalyst having titanium tetrachloride supported on a solid carrier containing anhydrous magnesium chloride as one component, and triethylaluminum (TEA)
Using the co-catalyst of 1-stage polymerization in a nitrogen atmosphere,
Polymers A1 and A2 of component (I) and polymers B1 to B3 of component (II) were produced. Table 1 shows the polymerization conditions and the physical properties of the obtained polymer.

[0023]

[Table 1]

[Preparation of Composition] Of the above-mentioned polymer, the component (I) and the component (II) were mixed and prepared by the solution mixing method under the following blending conditions. <Blend conditions> Atmosphere: Nitrogen Solvent: Xylene (4.5 liters) Sample amount: Total 200g Temperature: 200 ° C Time: 2 hours Deposition solvent: -20 ° C Methanol (8 liters) Cleaning solvent: Hexane Cleaning: Dry until xylene odor disappears: From room temperature to 110 ° C Polymer recovery rate: Almost 100%

Further, the above mixture and an ethylene (co) polymer obtained by the following high pressure radical polymerization of the component (III) under a nitrogen atmosphere, the total amount of the sample was 70 g, the rotation speed was 20 rpm,
Mixing was carried out at a kneading temperature of 160 ° C. for a kneading time of 7 minutes to obtain compositions of Examples and Comparative Examples. Ethylene (co) polymer by high-pressure radical polymerization: (1) Low density polyethylene (1) MFR 1.0g / 10min, density 0.924g / cm ³ ; Trade name: Nisseki Lexlon F22, manufactured by Nippon Petrochemical Co., Ltd. ( Below, "L
DPE-1 ") (2) Low density polyethylene (2) MFR 2.0g / 10min, density 0.924g / cm ³ ; Trade name: Nisseki Lexlon F311, manufactured by Nippon Petrochemical Co., Ltd. (hereinafter,
("LDPE-2") (3) Ethylene-vinyl acetate copolymer MFR 1.0g / 10min, vinyl acetate (VA) content 10% by weight; Trade name: Nisseki Lexlon V260, Nippon Petrochemical
Co., Ltd. (hereinafter referred to as "EVA") (4) Ethylene-ethyl acrylate copolymer MFR 1.0 g / 10 min, ethyl acrylate (EA) content 5
% By weight; Product name: Nisseki Lexron EEA A2050,
Made by Nippon Petrochemical Co., Ltd. (hereinafter referred to as "EEA")

<Examples 1 to 6> Table 2 shows the blending ratios of the compositions of Examples and the evaluation results of the physical properties.

[0027]

[Table 2]

<Comparative Examples 1 to 6> Table 3 shows the blending ratios and the evaluation results of physical properties of the compositions of Comparative Examples.

[0029]

[Table 3]

[0030]

INDUSTRIAL APPLICABILITY The polyethylene resin composition of the present invention is produced by an ultra-high molecular weight component, a specific ethylene / α-olefin copolymer or ethylene homopolymer having an extremely wide distribution of short chain branches between molecules, and high-pressure radical polymerization. A composition obtained by blending three components of an ethylene (co) polymer and having an extremely wide molecular weight distribution, which is excellent in balance of melt elasticity, flow characteristics, mechanical characteristics, etc., and specifically has the following characteristics. . (1) Excellent melt elasticity such as melt tension and die swell ratio. (2) Excellent mechanical properties at low temperature such as low temperature Izod impact value and cold resistance. (3) Excellent flow characteristics such as critical shear rate. (4) It has excellent optical characteristics such as haze. (5) Therefore, the molding processability such as high-speed molding property is good. As a result of having the above advantages, it is used for various films, sheets, pipes, hollow containers, various coating materials, foaming materials, etc., in particular because of its excellent melt elasticity and optical properties,
It is useful as a composition for large hollow containers.

[Brief description of drawings]

FIG. 1 is a diagram showing a relationship between an elution temperature and an elution amount by a continuous temperature rising elution fractionation method (TREF).

Claims (1)

[Claims] 1. An ultra-high molecular weight ethylene homopolymer or ethylene.α which satisfies the following conditions (a) and (b):
-Olefin copolymer 1 to 50% by weight, (a) intrinsic viscosity (η ₁ ) 9 to 45 dl / g, (b) density (d ₁ ) 0.890 to 0.935 g / cm ³ , (II) the following conditions Ethylene homopolymers or ethylene / α-olefin copolymers 5 to 94 satisfying (c) to (f)
% By weight, (c) intrinsic viscosity (η ₂ ) 0.3 to 3.0 dl / g, (d) density (d ₂ ) 0.890 to 0.980 g / cm ³ , (e) continuous temperature rising elution fractionation method In the elution temperature-elution amount curve according to, the ratio S (I of the area Ib under the curve of the elution temperature of 25 to 90 ° C. to the area Ia under the curve of the elution temperature of 90 ° C. or more
b / Ia) is S ₁ or less calculated from the following equation, S ₁ = 20 η ₂ ^-1 exp [−50 (d ₂ −0.900)] (f) 25 ° C. ortho-dichlorobenzene soluble content W weight% is calculated from the following equation. Calculated W ₁ or less, W ₁ = 100 η ₂ ^−0.5 exp [−50 η ₂ ^0.5 (d ₂ −0.900)], and (III) 5 to 50 wt% of ethylene (co) polymer by high pressure radical polymerization, And the above-mentioned components (I) and (II)
The total of (III) and (III) is 100% by weight, and the components (I) to (III) have different intrinsic viscosities, and the intrinsic viscosity of the mixture is 1.0 to 6.0 dl /
An ethylene polymer composition having g, a density of 0.890 to 0.970 g / cm ³ and an N-value of 1.7 to 3.0 calculated from the following formula 1. [Equation 1]