JP2017025160A - Ethylene polymer and hollow molded body - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ethylene polymer (α) high in impact resistance, excellent in long term fatigue resistance and creep resistance and excellent in product appearance and moldability, a hollow molded body consisting of the ethylene polymer (α) and a container having no appearance failure such as shark skin or the like on the product appearance and suitable for a large size container such as a fuel tank, a kerosene can, a drum can, a container for chemicals, a container for agrochemicals or the like.SOLUTION: The present invention relates to an ethylene polymer (α) having properties of [a] melt flow rate (HLMI) under a temperature of 190°C and load of 21.6 kg of 1.0 to 10 g/10 min., [b] density of 945 to 965 kg/m, [c] pressure (σ,Pa) at shear speed of 19460 sat 210°C by using a die with length of 5 mm and diameter of 0.5 mm and HLMI satisfying a relationship of log(σ)≥-0.12×log(HLMI)+7.65, [d] Charpy impact strength (MPa) at -40°C measured according to JIS K7111 and HLMI satisfying a relationship of log(Charpy impact strength)≥-1.1×log(HLMI)+2.16 and [e] swell ratio measured at 230°C of 1.56 or more.SELECTED DRAWING: None

Description

  The present invention relates to an ethylene polymer excellent in appearance and moldability as compared with conventionally known ethylene polymers and excellent in mechanical strength, and a hollow molded article comprising the same.

  In general, blow containers such as high-density polyethylene represented by gasoline tanks, drum cans, and chemical cans are manufactured by a hollow molding method. In the hollow molding method, an ethylene polymer is melted by an extruder and extruded into a cylindrical parison, and the parison is expanded and deformed by blowing a pressurized gas from a blow pin with the extruded parison sandwiched between molds. It cools after shaping into the cavity shape in a type | mold. Such a hollow molding method can be widely applied to gasoline tanks, drum cans, chemical cans, and panel-shaped molded products having complicated shapes, and is widely used in the industry because of the simple molding.

  Conventionally, metal tanks have been used as fuel tanks for internal combustion engines such as automobiles. However, in recent years, coupled with the background of the need for weight reduction for energy saving, rust does not occur, and it is molded into a desired shape. Plastic fuel tanks have come to be used for reasons such as being easy to do. Further, plastic drum cans and chemical cans have been demanded for further weight reduction in order to save energy and improve handling.

  In order to meet ever-increasing needs for thinning in the future, extremely high material properties are required for plastic hollow molded articles. In other words, it is required to have good appearance and formability, long-term fatigue characteristics such as good impact resistance and good environmental stress crack resistance, and creep resistance.

  Patent Document 1 discloses a polyethylene composition suitable for blow molding of a gasoline tank. This composition consists of a blend of a high molecular weight polymer and a low molecular weight polymer, and is produced using a Ziegler catalyst. However, it is expected that it is difficult to clear the above required characteristics with such a composition. In addition, the examples of Patent Document 2 and the example of Patent Document 3 disclose fuel tanks using an ethylene-based polymer manufactured with a titanium-based catalyst that is excellent in impact resistance even with a thin wall thickness. Yes. Patent Document 4 and Patent Document 5 similarly describe a multimodal polyethylene molding material having an improved ESCR-stiffness balance and swelling ratio, and a fuel manufactured from the hollow molding material. Hollow molding materials such as tanks are described.

  However, hollow bodies made of these ethylene-based polymers have excellent impact strength but are insufficient to meet the demand for further weight reduction, and are resistant to heat distortion under long-term stress, as typified by high-temperature tensile creep. May not be fully expressed.

  Patent Document 6 proposes a multimodal polyethylene in which at least a high molecular weight block is prepared with a metallocene catalyst, a tensile creep strain at 80 ° C. is 2.4% or less, and a Charpy impact at −40 ° C. is 15 KJ / m 2 or more. Yes.

  In addition, an ethylene polymer excellent in fluidity and moldability and excellent in many properties such as mechanical strength (Patent Document 7, Patent Document 8), an ethylene polymer that can be suitably used in a fuel tank (Patent Document 9) Has been proposed.

  However, hollow bodies made of these ethylene-based polymers have excellent impact strength, but polymerize high molecular weight blocks using a metallocene catalyst with a narrow molecular weight distribution, so there are fewer high molecular weight components than existing titanium catalysts ((z +1) The average molecular weight is small) and the elongational flow characteristics are inferior. Therefore, the high-speed flow field at the die exit causes destabilization on the surface of the molten resin, and there is a drawback that rough skin is likely to occur during molding.

  On the other hand, Patent Document 10 has a substantially narrow molecular weight distribution and a high Z average molecular weight by two or more highly active metallocene catalysts exhibiting different polymerization behaviors, and a high molecular weight component and a low molecular weight component are homogeneous. Describes ethylene-based polymers having molecular structural characteristics compatible with.

  However, these ethylene-based polymers have the disadvantages that, when hollow molding is performed, the molecular weight distribution (Mw / Mn) is narrow, the shear stress increases on the wall surface in the die, and rough skin tends to occur.

In Patent Document 11, a polymerization catalyst containing at least one salicylaldimine ligand-containing transition metal compound and a cyclopentadienyl ligand-containing transition metal compound is used to control the length and amount of long-chain branching. Thus, an ethylene polymer exhibiting excellent melt tension is described even in the single-stage polymerization method.
However, hollow bodies made of these ethylene-based polymers have a drawback that impact resistance and long-term fatigue properties are reduced by the introduction of long chain branching.

JP-A-6-172594 JP-A-7-090021 Japanese Patent Laid-Open No. 7-101433 JP 2003-510429 A JP 2006-193671 A JP 2005-523968 Gazette WO2004 / 083265 pamphlet WO2006 / 019147 pamphlet WO2008 / 087945 pamphlet JP 2005-206777 A JP 2005-2333 A

  The present inventors use a specific olefin polymerization catalyst to solve the above-mentioned various problems, that is, higher impact resistance, long-term fatigue characteristics and creep resistance characteristics than hollow molded bodies made of conventional polyolefin resin materials. The present inventors have found an ethylene-based polymer suitable for obtaining a hollow molded article that overcomes the disadvantages of the conventional hollow molded articles that are excellent in product appearance and moldability.

That is, the ethylene polymer (α) of the present invention is characterized by satisfying the following requirements [a], [b], [c], [d] and [e] simultaneously.
As long as the ethylene polymer (α) of the present invention satisfies the following requirements [a], [b], [c], [d] and [e] at the same time, Two or more kinds of ethylene polymers, or a mixture after kneading and blending known additives described later in such an amount that the total amount of additives is usually 1% by weight or less in the ethylene polymer. Good.

  In addition, the values of various parameters ([a] to [h]) defined by the claims of the present application for specifying the ethylene polymer (α) of the present invention are the values after blending, as in the examples described later. It is the measured value which made the granulated pellet the test object.

[a] The melt flow rate (HLMI) at a temperature of 190 ° C. and a load of 21.6 kg is in the range of 1.0 to 10 g / 10 min.
[b] The density is in the range of 945 to 965 kg / m ³ .

[c] Using a die having a length of 5.0 mm and a diameter of 0.5 mm, the relationship between pressure (σ, Pa) and HLMI at a shear rate of 19460 s ^-1 at 210 ° C. is in the following range.
log (σ) ≧ −0.12 × log (HLMI) +7.65
[d] The relationship between Charpy impact strength (MPa) measured at -40 ° C. according to JIS K7111, and HLMI is in the following range.
log (Charchy impact strength) ≥ -1.1 x log (HLMI) + 2.16
[e] The swell ratio measured at 230 ° C. is in the range of 1.56 or more.

  The ethylene polymer (α) of the present invention preferably satisfies the following requirement [f] in addition to the above requirements [a] to [e].

[f] In an environmental stress crack resistance test (ESCR test; test temperature 65 ° C., test piece thickness 3 mmt) measured according to ASTM D1693, the 50% crack generation time (F ₅₀ ) is 300 hours or more.

The ethylene polymer (α) of the present invention more preferably satisfies the following requirement [g] in addition to the above requirements [a] to [f].
[g] In a tensile creep test (test temperature: 80 ° C.) measured in accordance with JIS K7115, when the test stress is 6 MPa, the creep strain after 100 hours is 15% or less.

A particularly preferred embodiment of the ethylene polymer (α) of the present invention satisfies the following requirement [h] in addition to the above requirements [a] to [g].
[h] Mw / Mn and Mz _{+ 1} / Mw determined by gel permeation chromatography (GPC) measurement are in the following ranges.
4.0 ≦ (Mw / Mn) ≦ 22.0 and (Mz _{+ 1} / Mw) ≧ 16.0
The present invention relates to a hollow molded article including a layer made of the ethylene polymer (α).
The present invention relates to a fuel tank, a kerosene can, a drum can, a chemical container, an agrochemical container, a solvent container, or a bottle composed of the hollow molded body.

  That is, the fuel tank and the agricultural chemical container of the present invention are composed of the layer (I), the adhesive layer (IV), the barrier layer (II), and the regeneration layer (III) made of the above-described ethylene-based resin composition for hollow molded articles. It is characterized by being comprised from the hollow molded object containing a laminated structure.

Further, in the fuel tank and the agricultural chemical container of the present invention, the layer (I) and the barrier layer (II) made of the ethylene resin composition for a hollow molded body are laminated via an adhesive layer (IV). Is preferred. It is also preferable that the reproduction layer (III) and the barrier layer (II) are laminated via an adhesive layer.
In the fuel tank and the agricultural chemical container, the barrier layer (II) is preferably a layer containing an ethylene-vinyl alcohol copolymer.

  According to the present invention, it is possible to produce a hollow molded body and a multilayer hollow molded body made of an ethylene polymer (α) that are particularly excellent in appearance / moldability and mechanical strength.

Hereinafter, the ethylene polymer (α) of the present invention will be specifically described.
<Ethylene polymer (α)>
The ethylene-based polymer (α) of the present invention is an ethylene homopolymer or a copolymer of ethylene and an α-olefin having 4 to 10 carbon atoms, preferably ethylene and an α-olefin having 6 to 10 carbon atoms. is there. When an α-olefin having 4 carbon atoms is used as the α-olefin, it is also preferable to use an α-olefin having 6 to 10 carbon atoms. Examples of the α-olefin having 4 to 10 carbon atoms used for copolymerization with ethylene include 1-butene, 1-hexene, 4-methyl-1-pentene, 1-octene, and 1-decene.

  When the number of carbon atoms of the α-olefin is 5 or less, the probability that the α-olefin is incorporated into the crystal is high (see Polymer, vol. 31, 1999, 1990). The strength tends to be weak. In addition, if the α-olefin has more than 10 carbon atoms, the side chain (branch caused by the α-olefin copolymerized with ethylene) may crystallize. As a result, the resulting hollow molded body is amorphous. Part tends to be weak.

The structural unit derived from an α-olefin is usually contained in an amount of generally 2.0 mol% or less, preferably 1.5 mol% or less, more preferably 1.30 mol% or less in all the structural units.
As will be described later, when the ethylene polymer is continuously polymerized in two or more stages, for example, only ethylene is homopolymerized in the first stage, and ethylene and α-olefin are copolymerized in the second stage. Also good. In this case, the above-mentioned “all structural units” means all the structural units of the polymer finally obtained by continuous polymerization in two or more stages.

  The ethylene polymer (α) of the present invention may be unimodal (monomodal) or multimodal (low molecular weight polymer and high molecular weight polymer as described later). It is preferable that it is multimodal to polymerize since it is easy to control various parameter ranges defined in the present invention.

The ethylene polymer (α) of the present invention is characterized by satisfying the following requirements [a] to [d] simultaneously.
In addition, as long as the ethylene polymer (α) of the present invention satisfies the following requirements [a] to [d] at the same time, even if it is a single ethylene polymer, a mixture of two or more ethylene polymers, Or a composition may be sufficient.

  [a] Melt flow rate (HLMI) under a temperature of 190 ° C. and a load of 21.6 kg is 1.0 to 10 g / 10 minutes, preferably 1.5 to 7.0 g / 10 minutes, more preferably 1.5 to It is in the range of 3.7 g / 10 min.

  When the HLMI is less than 1.0 g / 10 min, the load on the extruder increases during the extrusion of the parison, and the amount of extrusion cannot be ensured sufficiently, and the productivity may be lowered. If it exceeds / 10 minutes, the melt parison formation may become unstable due to insufficient melt viscosity or melt tension, and the impact strength of the resulting hollow molded article is reduced, which is not preferable.

  HLMI mainly depends on the molecular weight of the ethylene polymer, and it is known that the molecular weight of the ethylene polymer is determined by the composition ratio (hydrogen / ethylene) of hydrogen and ethylene in the polymerization system ( For example, Kazuo Soga et al., “Catalytic Olefin Polymerization”, Kodansha Scientific, 1990, p.376). For this reason, it is possible to increase / decrease HLMI of an ethylene-type polymer by increasing / decreasing hydrogen / ethylene.

[b] The density is in the range of 945 to 965 kg / m ³ , preferably 948 to 960 kg / m ³ , more preferably 949 to 959 kg / m ³ .
An ethylene-based polymer having a density of less than 945 kg / m ³ is not preferable because the resulting hollow molded article lacks rigidity, or when used as a fuel tank, the rigidity is liable to decrease due to swelling. ^An ethylene-based polymer exceeding ³ is not preferable because the resulting hollow molded article becomes brittle and does not exhibit long-term fatigue characteristics such as impact resistance and ESCR characteristics.

  The density mainly depends on the α-olefin content of the ethylene polymer. The smaller the α-olefin content, the higher the density, and the higher the α-olefin content, the lower the density. In addition, it is known that the α-olefin content in an ethylene polymer is determined by the composition ratio (α-olefin / ethylene) of α-olefin and ethylene in the polymerization system (for example, Walter Kaminsky, Makromol. Chem. 193, p.606 (1992)). For this reason, the ethylene polymer ((alpha)) which has the density of the said range can be manufactured by increasing / decreasing (alpha) -olefin / ethylene.

[c] Using a die having a length of 5.0 mm and a diameter of 0.5 mm, the relationship between the pressure (σ, Pa) and the HLMI at an apparent shear rate of 19460 s ^-1 at 210 ° C. is expressed by the following inequality (Eq-1 Is satisfied. Preferably the following inequality (Eq-1-2) is satisfied, and particularly preferably, the following inequality (Eq-1-3) is satisfied.
log (σ) ≧ −0.12 × log (HLMI) +7.65 (Eq−1)
log (σ) ≧ −0.12 × log (HLMI) +7.66 (Eq-1-2)
log (σ) ≧ −0.12 × log (HLMI) +7.68 (Eq-1-3)

  In the high-speed flow field at the die exit, the unstable phenomenon of rough skin such as sharkskin that occurs on the surface of molten resin such as ethylene polymer is related to the elongation flow characteristics in the high-speed large deformation field, and the amount of deformation is large. It is known that sharkskins are less likely to occur in systems that can maintain elongation stress in the region. (For example, T.I.Burghelea et al, / J.Non-Newtonian Fluid Mech.165 (2010) 1093-1104).

The following methods are known as methods for evaluating the elongational flow characteristics in a high-speed large deformation field.
In capillary rheometers, elongation flow occurs in the flow direction due to the reduced flow that occurs when molten resin flows from the barrel into the die, but in a high-speed large deformation field, resistance to this elongation flow, that is, pressure loss based on elongation viscosity, It is known to be dominant and sufficiently large compared to the pressure loss caused by shear flow (for example, Cogswell, FN Polym. Eng. Sci. 1972, 12, 64). Therefore, by using a die that can generate a high-speed large deformation field at the inflow portion of the die by reducing the diameter of the die, and can further reduce the shear pressure loss by shortening the land of the die. Can be used to evaluate the elongational flow characteristics of a high-speed large deformation field.

In general, it is known that introduction of a long chain branch and / or introduction of a high molecular weight component into an ethylene polymer is effective for improving the elongational flow characteristics. Monomodal ethylene polymers prepared with metallocene catalysts are known to have a narrow molecular weight distribution and have a lower molecular weight component than monomodal ethylene polymers prepared with Ziegler-Natta catalysts (ie M _{Z + 1} ) The average molecular weight is small), and it is expected that the elongational flow characteristics are inferior.

By adjusting a bimodal polyethylene resin composition using a metallocene catalyst as described in the pamphlet of WO2008 / 087945, it is possible to adjust polyethylene excellent in fluidity and impact strength. However, since the high molecular weight component of the bimodal polyethylene resin composition using the metallocene catalyst is less than the bimodal polyethylene prepared by the Ziegler-Natta catalyst (ie, the M _{Z + 1} average molecular weight is small), the elongational flow characteristics are improved. There is a tendency to be inferior, and there is a tendency that shark skin is likely to occur in a high-speed flow field at the die outlet during blow molding. The elongational flow characteristics can be improved by further increasing the molecular weight of the high molecular weight polymer using a metallocene catalyst, but poor appearance due to poor dispersion of the low molecular weight polymer component and the high molecular weight polymer component during blow molding. It becomes easy to generate | occur | produce, and the shape of the pinch-off part (a fusion part which pinched | interposed the parison with the metal mold | die) and the fusion strength become inferior. In addition, it is possible to introduce a high molecular weight polymer having a higher molecular weight than a high molecular weight polymer obtained from a bimodal polyethylene by adjusting a multimodal or higher multimodal polyethylene using a metallocene catalyst. A polyethylene having a high molecular weight component having a high molecular weight (that is, a component having a large M _{Z + 1} average molecular weight) can be obtained, which is preferable from the viewpoint of an increase in capital investment due to an increase in polymerization equipment and dispersibility of a high molecular weight polymer having a higher molecular weight. Absent.

Also, the introduction of long chain branching can improve the elongational flow characteristics, but this is not preferable because impact resistance and long-term fatigue characteristics are likely to deteriorate.
In the ethylene-based polymer (α) of the present invention, an olefin polymerization catalyst comprising a Group 4 transition metal compound capable of producing a high molecular weight polymer (hereinafter referred to as “A-1” in the description). ) And an olefin polymerization catalyst (hereinafter sometimes referred to as “A-2” in the description) comprising a Group 4 transition metal compound capable of producing a further high molecular weight polymer. By adjusting the bimodal (two-stage polymerization) ethylene polymer in the presence of an olefin polymerization catalyst consisting of a Group 4 transition metal compound, it is possible to maintain an extensional stress even in a region where the amount of deformation during melting is large. It is possible to obtain an ethylene polymer (α) with excellent elongation flow characteristics and to suppress the shark skin generated on the surface of the parison in the high-speed flow field at the die outlet during hollow molding. The

[d] The relationship between Charpy impact strength (MPa) at −40 ° C. measured in accordance with JIS K7111, and HLMI satisfies the following inequality (Eq-2). Preferably the following inequality (Eq-2-2), more preferably the following inequality (Eq-2-3) and the following inequality (Eq-2-4) simultaneously, and particularly preferably the following inequality (Eq-2-4) and The following inequality (Eq-2-5) is satisfied at the same time.
log (Charchy impact strength) ≥ -1.1 x log (HLMI) + 2.16 ... (Eq-2)
log (Charchy impact strength) ≥ -1.1 x log (HLMI) + 2.19 ... (Eq-2-2)
log (Charch impact strength) ≧ −1.1 × log (HLMI) +2.20 (Eq-2-3)
log (Charchy impact strength) ≧ 1.6 (Eq-2-4)
log (Charch impact strength) ≧ −1.1 × log (HLMI) +2.25 (Eq-2-5)

  When the Charpy impact strength is within this range, the obtained hollow molded body can sufficiently withstand the impact to the hollow molded body caused by vibration, dropping, vehicle accidents, and drop impact. Further, increasing the container thickness in order to improve the impact resistance impairs the economy. The Charpy impact strength can be adjusted by the density of the ethylene polymer and HLMI, and the Charpy impact strength can be increased by decreasing the density or decreasing the HLMI.

[e] The swell ratio measured at 230 ° C. is 1.56 or more.
The swell ratio of the ethylene-based polymer (α) of the present invention is 1.56 or more, preferably 1.60 or more. Swell is a phenomenon in which the resin melt extruded from a die becomes larger in size than the slit width and clearance at the die outlet. If the swell ratio is small, molding control such as parison is difficult during blow molding. It is not preferable because the properties deteriorate, and a large swell ratio is required to adjust the thickness of the product. Swell is an intrinsic viscosity of an ethylene polymer polymerized from an olefin polymerization catalyst comprising a Group 4 transition metal compound (A-2) capable of producing a further high molecular weight polymer [ By increasing η], the swell can be increased.

  The ethylene polymer (α) of the present invention preferably satisfies the following requirement [f] or [g] in addition to the requirements [a] to [e]. Furthermore, it is more preferable to satisfy the requirements [f] and [g] at the same time.

[f] In an environmental stress crack resistance test (ESCR test; test temperature 65 ° C., specimen thickness 3 mmt) measured according to ASTM D1693, 50% crack generation time (F ₅₀ ) is 300 hours or more, preferably 400 The time is more than 500 hours, more preferably 500 hours or more. The F ₅₀ is less than 300 hours, poor environmental stress cracking resistance, caused destruction of the container due to environmental stress cracking, there is a possibility that the content liquid is leaking. F ₅₀ of the ESCR tests, can be adjusted by the molecular weight and density and the amount of high molecular weight polymers of ethylene polymer, when increasing the proportion or reduce or density to increase the molecular weight of the high molecular weight polymer, the F ₅₀ can be improved.

  [g] In a tensile creep test (test temperature 80 ° C.) measured in accordance with JIS K7115, when the test stress is 6 MPa, the creep strain after 100 hours has elapsed is 15% or less, preferably 10% or less, more preferably Is 9.5% or less, particularly preferably 9.0% or less.

When the creep strain is in the above range, the creep deformability is excellent particularly at high temperatures, that is, the heat deformation is superior to conventional materials in a high temperature region assumed when the hollow molded body is actually used in a fuel tank or the like. Therefore, the thickness of the hollow molded body can be reduced. Creep strain can be adjusted by the density of the ethylene polymer and HLMI, and the creep strain can be reduced by increasing the density or decreasing the HLMI.
The ethylene polymer (α) of the present invention preferably satisfies the following requirement [h] in addition to the requirements [a] to [g].

[h] The relationship between Mw / Mn and Mz _{+ 1} / Mw determined by gel permeation chromatography (GPC) measurement is the following inequality (Eq-3-1) and the following inequality (Eq-3-2). Meet at the same time. Preferably, the following inequality (Eq-3-2) and the following inequality (Eq-3-3) are satisfied simultaneously, and particularly preferably the following inequality (Eq-3-4) and the following inequality (Eq-3-5) are satisfied simultaneously.
4.0 ≦ (Mw / Mn) ≦ 22.0 (Eq-3-1)
(Mz _{+ 1 /} Mw) ≧ 16.0 (Eq-3-2)
6.0 ≦ (Mw / Mn) ≦ 21.0 (Eq-3-3)
8.0 ≦ (Mw / Mn) ≦ 20.0 (Eq-3-4)
(Mz _{+ 1 /} Mw) ≧ 17.0 (Eq-3-5)

An ethylene polymer having Mw / Mn of less than 4.0 is not preferable because the extrusion load at the time of molding becomes too high, causing a problem in workability, and the parison becomes unstable at the time of hollow molding.
An ethylene-based polymer having an Mw / Mn of greater than 22.0 is liable to cause poor appearance during blow molding due to poor dispersion of a low molecular weight polymer and a high molecular weight polymer, and has an intrinsic viscosity [η] of 5.0 or less. In such an ethylene polymer, a low-molecular-weight component is excessively increased, and thus a hollow molded product obtained is not preferable because it does not exhibit impact resistance. In addition, the shape and the fusion strength of the pinch-off portion of the parison coupling portion (the fusion portion where the parison is sandwiched between the molds) and the fusion strength are deteriorated, and the drop strength may be lowered.

Mz _{+ 1} / Mw represents the molecular weight distribution of the high molecular weight component, and represents the molecular weight distribution of the component having a higher molecular weight than Mz / Mw. A large Mz _{+ 1} / Mw with respect to Mw / Mn means that the molecular weight distribution of the high molecular weight component is wide, there is a very high molecular weight component, and the component ratio is further high.

An ethylene polymer having an Mz _{+ 1} / Mw greater than 16.0 is excellent in elongational flow characteristics due to a very high molecular weight component contained in the ethylene polymer. Since it is stable, it is possible to prevent rough skin during molding at the die outlet.

The upper limit of Mz _{+ 1} / Mw of the ethylene polymer (α) of the present invention is not particularly limited, but preferably Mz _{+ 1} / Mw is preferably 70.0 or less, particularly preferably 50.0 or less. If Mz ₊₁ / Mw is too large, the component having a very high molecular weight may be crushed and may cause poor dispersion, and the shear stress may be increased on the wall surface in the die, resulting in rough skin inside the die.

  In addition to satisfying the above requirements [a] to [g], the ethylene polymer (α) of the present invention has an intrinsic viscosity [η] of 2.5 to 6.0 (dl / g), preferably 3. It is a particularly preferable embodiment that 0 to 5.0 (dl / g) is also satisfied. An ethylene polymer having an intrinsic viscosity in this range exhibits extremely excellent characteristics in fluidity, rigidity and low temperature impact resistance.

<Method for producing ethylene polymer (α)>
The ethylene polymer (α) of the present invention is an olefin polymerization catalyst, for example,
(A-1) a transition metal compound of Group 4 of the periodic table represented by the following general formula [I] (hereinafter may be referred to as “A-1”);
(A-2) Periodic Table Group 4 transition metal compound represented by the following general formula [III] (sometimes referred to as “A-2” in the description below) and (B) (B-1) organic Metal compounds,
(B-2) an organoaluminum oxy compound, and
(B-3) At least one compound selected from compounds that react with transition metal compounds to form ion pairs (hereinafter sometimes referred to as “cocatalyst”) and used as necessary (C ) It can be preferably produced by homopolymerizing ethylene using an olefin polymerization catalyst formed from a carrier or copolymerizing ethylene and the above-mentioned α-olefin having 6 to 10 carbon atoms. it can.

Hereinafter, each component (A-1), (A-2), (B) and (C) will be described in detail.
(A-1) Transition metal compound The transition metal compound (A-1) is a compound represented by the following general formula [I].

上記一般式[I]において、R⁷、R⁸、R⁹、R¹⁰、R¹¹、R¹²、R¹³、R¹⁴、R¹⁵、R¹⁶、R¹⁷、R¹⁸、R¹⁹およびR²⁰は、それぞれ水素原子、炭化水素基、であり、それぞれ同一でも異なっていてもよく、R⁷〜R¹⁸までの隣接した置換基は互いに結合して環を形成してもよく、R¹⁹およびR²⁰は不飽和結合および/または芳香族環を含んでいてもよい炭素原子数2〜20の2価の炭化水素基であり、Mは周期律表第4族から選ばれた金属であり、Qはハロゲン原子、炭化水素基、アニオン配位子または孤立電子対で配位可能な中性配位子から同一または異なる組合せで選ばれ、jは1〜4の整数である。

In the above general formula [I], R ⁷ , R ⁸ , R ⁹ , R ¹⁰ , R ¹¹ , R ¹² , R ¹³ , R ¹⁴ , R ¹⁵ , R ¹⁶ , R ¹⁷ , R ¹⁸ , R ¹⁹ and R ²⁰ are Each of them may be the same or different, and adjacent substituents from R ^{7 to} R ¹⁸ may be bonded to each other to form a ring, and R ¹⁹ and R ²⁰ Is a divalent hydrocarbon group having 2 to 20 carbon atoms which may contain an unsaturated bond and / or an aromatic ring, M is a metal selected from Group 4 of the periodic table, and Q is A halogen atom, a hydrocarbon group, an anionic ligand, or a neutral ligand capable of coordinating with a lone electron pair is selected in the same or different combination, and j is an integer of 1 to 4.

Among the transition metal compounds (A-1) represented by the above general formula [I], R ^{7 to} R ¹⁰ are hydrogen atoms, Y is a carbon atom, and M is zirconium. An atom and j is 2.

In the transition metal compound (A-1) represented by the above general formula [I], the bridging atoms Y of the covalent bond bridging portions have aryl groups that may be the same or different from each other. (That is, R ¹⁹ and R ²⁰ are aryl groups which may be the same or different from each other). Examples of the aryl group include a phenyl group, a naphthyl group, an anthracenyl group, and a group in which one or more of these aromatic hydrogens (sp2-type hydrogen) are substituted with a substituent. Examples of the substituent include a hydrocarbon group (f1) having a total carbon number of 1 to 20. Examples of such a group (f1) include methyl, ethyl, n-propyl, allyl, n-butyl, n-pentyl, n-hexyl, n-heptyl, and n-octyl. Group, a linear hydrocarbon group such as n-nonyl group, n-decanyl group; isopropyl group, tert-butyl group, amyl group, 3-methylpentyl group, 1,1-diethylpropyl group, 1,1-dimethyl group Branched butyl, 1-methyl-1-propylbutyl, 1,1-propylbutyl, 1,1-dimethyl-2-methylpropyl, 1-methyl-1-isopropyl-2-methylpropyl, etc. Hydrocarbon group; Cyclic saturated hydrocarbon group such as cyclopentyl group, cyclohexyl group, cycloheptyl group, cyclooctyl group, norbornyl group, adamantyl group; cyclic unsaturated group such as phenyl group, naphthyl group, biphenyl group, phenanthryl group, anthracenyl group Hydrocarbon group and this Saturated hydrocarbon groups substituted with aryl groups such as benzyl group and cumyl group; methoxy group, ethoxy group, phenoxy group, N-methylamino group, trifluoromethyl group, tribromomethyl group, pentafluoro There can be mentioned heteroatom-containing hydrocarbon groups such as an ethyl group and a pentafluorophenyl group.

  In the present invention, the hydrocarbon group (f1) is preferably a cyclic saturated hydrocarbon group or a nuclear alkyl substituent, and a more preferred specific example is a metallocene compound represented by the compound [II]. .

なお、上記式[II]で表わされる遷移金属化合物は、270MHz ¹H-NMR（日本電子 GSH-270）およびFD-質量分析（日本電子SX-102A）などを用いて同定することができる。

The transition metal compound represented by the above formula [II] can be identified using 270 MHz ¹ H-NMR (JEOL GSH-270), FD-mass spectrometry (JEOL SX-102A), or the like.

(A-2) Transition metal compound The transition metal compound (A-2) is a compound represented by the following general formula [III].
The polyethylene polymer (α) of the present invention can be produced by using the following transition metal compound [III] together with the transition metal compound represented by the above formula [I]. In particular, it is preferably used together with the transition metal compound [II].

  The transition metal compound of the component (A-2) used in the present invention is a group 4 transition metal compound represented by the following general formula [III]. The transition metal compound of Group 4 of the periodic table represented by the following general formula [III] will be described in detail.

〔一般式［III］中、Ｍは周期律表第４族遷移金属原子を示し、ｍは、１〜４の整数を示し、Ｒ¹〜Ｒ⁵は、水素原子、炭化水素基、ケイ素含有基を示し、互いに同一でも異なっていてもよく、これらのうちの２個以上が互いに連結して環を形成していてもよく、ｍが２以上の場合にはＲ¹〜Ｒ⁵で示される基のうち少なくとも２個の基が連結されていてもよく、Ｒ⁶は、下記一般式［IV］で表される基であり、ｊは、Ｍの価数を満たす数であり、Ｘは、水素原子、ハロゲン原子、炭化水素基、酸素含有基、イオウ含有基、窒素含有基、ホウ素含有基、アルミニウム含有基、リン含有基、ハロゲン含有基、ヘテロ環基、ケイ素含有基、ゲルマニウム含有基、またはスズ含有基を示し、ｊが２以上の場合は、Ｘで示される複数の基は互いに同一でも異なっていてもよく、またＸで示される複数の基は互いに結合して環を形成してもよい。〕

[In General Formula [III], M represents a Group 4 transition metal atom in the periodic table, m represents an integer of 1 to 4, and R ^{1 to} R ⁵ represent a hydrogen atom, a hydrocarbon group, or a silicon-containing group. Which may be the same or different from each other, and two or more of them may be connected to each other to form a ring, and when m is 2 or more, the groups represented by R ^{1 to} R ⁵ At least two groups may be linked, R ⁶ is a group represented by the following general formula [IV], j is a number satisfying the valence of M, and X is hydrogen Atoms, halogen atoms, hydrocarbon groups, oxygen-containing groups, sulfur-containing groups, nitrogen-containing groups, boron-containing groups, aluminum-containing groups, phosphorus-containing groups, halogen-containing groups, heterocyclic groups, silicon-containing groups, germanium-containing groups, or Represents a tin-containing group, and when j is 2 or more, the plurality of groups represented by X may be the same as each other May have become, the a plurality of groups may be bonded to each other to form a ring represented by X. ]

In the general formula [III], N... M generally indicates coordination, but may or may not be coordinated in the present invention.
In the general formula [I], M is specifically titanium, zirconium or hafnium, preferably zirconium.
m is preferably 2.

  In the general formula [III], X represents a hydrogen atom, a halogen atom, a hydrocarbon group, an oxygen-containing group, a sulfur-containing group, a nitrogen-containing group, a boron-containing group, an aluminum-containing group, a phosphorus-containing group, a halogen-containing group, or a heterocyclic ring. Group, a silicon-containing group, a germanium-containing group, or a tin-containing group, among which a hydrogen atom, a halogen atom, a hydrocarbon group, or a silicon-containing group is preferable.

Examples of the halogen atom include fluorine, chlorine, bromine and iodine, but chlorine is most preferably used.
In the general formula [III], examples of ^{R 1 ~R 5, R 1 ~R} 5 represent a hydrogen atom, a hydrocarbon group, and may be the same or different from each other, connecting two or more of these with each other ^May form a ring, and when m is 2 or more, at least two groups among the groups represented by R ^{1 to} R ⁵ may be linked. R ^{1 to} R ⁵ may be the same as or different from each other, and at least two of the groups represented by R ^{1 to} R ⁵ may be linked. Of these, a hydrogen atom and a hydrocarbon group are particularly preferable.

Specific examples of the hydrocarbon group include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, neopentyl, n-hexyl, and adamantyl. A linear or branched alkyl group having 1 to 30 carbon atoms, preferably 1 to 20 carbon atoms, such as a phenyl group, a naphthyl group, a biphenyl group, a terphenyl group, a phenanthryl group, an anthracenyl group, etc. An aryl group having 6 to 30 carbon atoms, preferably 6 to 20 carbon atoms may be substituted. Among them, R ² or R ³ is a methyl group, an ethyl group, or an optionally substituted phenyl group, and R ⁵ is a t-butyl group, an adamantyl group, a dimethylphenyl group, or a methyldiphenyl group. It is preferable from the viewpoint that the polymer of the invention can be obtained.

In the general formula [III], R ⁶ is a group represented by [IV] (where a black circle (●) represents a bonding point with a nitrogen atom).

一般式［ＩＶ］中、Ｒ¹³は、炭素数３以上８以下の二価の飽和炭化水素基であり、例えば、トリメチレン、テトラメチレン、ペンタメチレン、ヘキサメチレンなどが挙げられ、好ましくは炭素数４以上６以下の二価の飽和炭化水素基（例えば、テトラメチレン、ペンタメチレン、ヘキサメチレン）であり、特に好ましくは炭素数４の二価の飽和炭化水素基（例えば、テトラメチレン）である。

In the general formula [IV], R ¹³ is a divalent saturated hydrocarbon group having 3 to 8 carbon atoms, and examples thereof include trimethylene, tetramethylene, pentamethylene, hexamethylene, etc., preferably 4 carbon atoms. The divalent saturated hydrocarbon group (for example, tetramethylene, pentamethylene, hexamethylene) having 6 or less is particularly preferable, and the divalent saturated hydrocarbon group having 4 carbon atoms (for example, tetramethylene) is particularly preferable.

In the general formula [IV], R ¹² and R ¹⁴ represent a halogen atom or a C1-C20 hydrocarbon group, may be branched or cyclic, and may be the same or different from each other. Examples of the hydrocarbon include the same groups as those exemplified above for R ^{1 to} R ⁵ , and even if they are aliphatic, they can be cited as examples, but the characteristic polymer of the present application is obtained. Therefore, it is preferable to use an aliphatic hydrocarbon. R ¹² is preferably located at the α-position of the carbon in which the formula [IV] is bonded to nitrogen from the viewpoint of obtaining the ethylene polymer of the present application.

  Of these, in particular, the number of carbon atoms such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, neopentyl, n-hexyl, etc. 1-30, preferably 1-20 linear or branched alkyl groups; 6-30 carbon atoms such as phenyl, naphthyl, biphenyl, terphenyl, phenanthryl, anthracenyl, etc., preferably 6 An aryl group having ˜20; a halogen atom, an alkyl group or alkoxy group having 1 to 30 carbon atoms, preferably 1 to 20 carbon atoms, an aryl group having 6 to 30 carbon atoms, preferably 6 to 20 carbon atoms, or aryloxy A substituted aryl group substituted with 1 to 5 substituents such as a group is preferred.

n is 0 or an integer less than twice the number of carbon atoms of R ¹³ , and when n is an integer of 2 or more, the plurality of R ¹⁴ may be the same or different from each other.
In the general formula [IV], a black circle (●) represents a bonding point with a nitrogen atom.
In the general formula [III], j is a number satisfying the valence of M, specifically 0 to 5, preferably 1 to 4, more preferably an integer of 1 to 3.

In general formula [III], X represents a hydrogen atom, a halogen atom, a hydrocarbon group, an oxygen-containing group, a sulfur-containing group, a nitrogen-containing group, a boron-containing group, an aluminum-containing group, a phosphorus-containing group, a halogen-containing group, or a heterocyclic ring. A containing group, a silicon-containing group, a germanium-containing group, or a tin-containing group, and when j is 2 or more, a plurality of groups represented by X may be the same or different from each other, and a plurality of groups represented by X The groups may be bonded to each other to form a ring.
From the above points, the most preferable compounds for obtaining the ethylene polymer of the present application are listed below.

前記第４族遷移金属化合物の具体的な例においてｔ−Ｂｕはｔｅｒｔ−ブチル基を表し、Ｐｈはフェニル基を表し、Ｍｅはメチル基を表し、Ａｄｍは１−アダマンチル基を示す。

In specific examples of the Group 4 transition metal compound, t-Bu represents a tert-butyl group, Ph represents a phenyl group, Me represents a methyl group, and Adm represents a 1-adamantyl group.

  In the present invention, in these compounds, transition metal compounds in which zirconium is replaced with a Group 4 transition metal other than zirconium, such as titanium and hafnium, can also be used.

  The method for producing such a transition metal compound (A-2) is not particularly limited, and can be produced, for example, by the methods described in Japanese Patent Application Laid-Open No. 11-315109 and EP 08744005A1 by the present applicant.

In the present invention, the transition metal compound (A-2) represented by the formula [III] is represented by R ⁶ in the formula [III] because a substituent exists at R ¹² in the formula [IV]. The rotation of the substituent is suppressed, the reaction field in the vicinity of the transition metal is narrowed, and chain transfer to the monomer or Al is less likely to occur, so that the molecular weight is increased and a high molecular weight olefin polymer is obtained. On the other hand, since the activity may be lowered if the reaction field becomes too narrow, the substituent of R ¹² in the formula [IV] is a hydrocarbon group, preferably a methyl group, an ethyl group, n -A propyl group, n-butyl group, More preferably, a methyl group is mentioned.
Two or more different compounds can be used as the component of the general formula (IV).

(B) Cocatalyst [(B-1) Organometallic compound]
Specific examples of the (B-1) organometallic compound include the following organometallic compounds of Groups 1, 2 and 12, 13 of the periodic table.

General formula R ^a _m Al (OR ^b ) _n H _p X _q
(In the formula, R ^a and R ^b may be the same or different from each other, each represents a hydrocarbon group having 1 to 15 carbon atoms, preferably 1 to 4 carbon atoms, X represents a halogen atom, and m represents 0. <M ≦ 3, n is 0 ≦ n <3, p is 0 ≦ p <3, q is a number 0 ≦ q <3, and m + n + p + q = 3). It is an organoaluminum compound.
The aluminum compound used in the examples described later is triisobutylaluminum or triethylaluminum.

[(B-2) Organoaluminum oxy compound]
The organoaluminum oxy compound (B-2) used as necessary in the present invention may be a conventionally known aluminoxane, or a benzene-insoluble organoaluminum exemplified in JP-A-2-78687. It may be an oxy compound.
The organoaluminum oxy compound used in the examples described later is a commercially available MAO (= methylalumoxane) / toluene solution manufactured by Nippon Alkyl Aluminum Co., Ltd.

[(B-3) Compound that reacts with transition metal compound to form ion pair]
Compound (B-3) used in the present invention to react with transition metal compound (A-1) and transition metal compound (A-2) to form an ion pair (hereinafter referred to as “ionized ionic compound”). As JP-A-1-501950, JP-A-1-502036, JP-A-3-17905, JP-A-3-179006, JP-A-3-207703, JP-A-3-207704 And Lewis acids, ionic compounds, borane compounds and carborane compounds described in US Pat. Furthermore, heteropoly compounds and isopoly compounds can also be mentioned. Such ionized ionic compounds (B-3) are used singly or in combination of two or more.
In addition, as (B) component which is not limited, in the Example mentioned later, the said (B-1) and (B-2) are used together.

(C) Particulate carrier The particulate carrier (C) used as necessary in the present invention is an inorganic or organic compound, and is a granular or particulate solid. Among these, as the inorganic compound, a porous oxide, an inorganic halide, clay, clay mineral, or an ion-exchange layered compound is preferable. Such porous oxides have different properties depending on the type and production method, but the carrier preferably used in the present invention has a particle size of 1 to 300 μm, preferably 3 to 200 μm, and a specific surface area of 50 to 1000. (m ² / g), preferably in the range of 100 to 800 (m ² / g), and the pore volume is in the range of 0.3 to 3.0 (cm ³ / g). Such a carrier is used after being calcined at 80 to 1000 ° C., preferably 100 to 800 ° C., if necessary.

  The catalyst for olefin polymerization according to the present invention includes the transition metal compound (A-1) and the transition metal compound (A-2), (B-1) an organometallic compound, (B-2) an organoaluminum oxy compound, And (B-3) at least one compound (B) selected from ionized ionic compounds, and a particulate carrier (C) used as necessary, and a specific organic compound component as described later as necessary (D) can also be included.

(D) Organic Compound Component In the present invention, the (D) organic compound component is used for the purpose of improving the polymerization performance and the physical properties of the produced polymer, if necessary. Examples of such organic compounds include alcohols, phenolic compounds, carboxylic acids, phosphorus compounds, and sulfonates.

  The ethylene polymer according to the present invention is obtained by homopolymerizing ethylene as described above using the above olefin polymerization catalyst or copolymerizing ethylene and an α-olefin having 6 to 10 carbon atoms. Or the homopolymerization and the copolymerization are carried out continuously in an arbitrary order.

In the polymerization, the method of using each component and the order of addition are arbitrarily selected, and the following methods (P1) to (P10) are exemplified.
(P1) at least one selected from components (A-1) and (A-2), (B-1) an organometallic compound, (B-2) an organoaluminum oxy compound, and (B-3) an ionized ionic compound A method of adding seed component (B) (hereinafter simply referred to as “component (B)”) to the polymerization vessel in an arbitrary order.

(P2) A method in which a catalyst obtained by previously contacting components (A-1) and (A-2) with component (B) is added to the polymerization reactor.
(P3) A method in which components (A-1) and (A-2) and a catalyst component in which component (B) are contacted in advance, and component (B) are added to the polymerization vessel in any order. In this case, each component (B) may be the same or different.

(P4) A method in which components (A-1) and (A-2) are supported on a particulate carrier (C), and a component (B) is added to the polymerization vessel in any order.
(P5) A method in which the catalyst component in which the components (A-1) and (A-2) and the component (B) are supported on the particulate carrier (C) is added to the polymerization vessel.

  (P6) A method in which the components (A-1) and (A-2) and the component (B) are supported on the particulate carrier (C) and the component (B) are added to the polymerization vessel in any order. . In this case, each component (B) may be the same or different.

(P7) A method in which the catalyst component having the component (B) supported on the particulate carrier (C) and the components (A-1) and (A-2) are added to the polymerization vessel in an arbitrary order.
(P8) A method in which the catalyst component, the components (A-1) and (A-2), and the component (B) in which the component (B) is supported on the particulate carrier (C) are added to the polymerization vessel in any order. In this case, each component (B) may be the same or different.

  (P9) Polymerizing a catalyst component in which the components (A-1) and (A-2) and the component (B) are supported on the particulate carrier (C) and the component (B) in contact with each other. How to add to the vessel. In this case, each component (B) may be the same or different.

  (P10) a catalyst component in which the components (A-1) and (A-2) and the component (B) are supported on the particulate carrier (C), and the catalyst component in which the component (B) is contacted in advance, and the component A method of adding (B) to the polymerization vessel in an arbitrary order. In this case, each component (B) may be the same or different.

In the above methods (P1) to (P10), at least two or more of the catalyst components may be contacted in advance.
A method using the solid catalyst component in which the components (A-1) and (A-2) and the component (B) are supported on the particulate carrier (C), that is, (P5), (P6), (P9) ) And (P10), an olefin may be prepolymerized. This prepolymerized solid catalyst component is usually prepolymerized at a ratio of 0.1 to 1000 g, preferably 0.3 to 500 g, particularly preferably 1 to 200 g of polyolefin per 1 g of the solid catalyst component. Examples of the olefin to be subjected to the prepolymerization include ethylene or the above-mentioned α-olefin having 6 to 10 carbon atoms, and among these, ethylene is preferably used. In the present invention, an ethylene polymer is usually prepared by a method using a fine particle carrier (C), and preferably the components (A-1) and (A-2) and the component (B) are combined with a fine particle carrier (C). The catalyst component in which ethylene is pre-polymerized on the catalyst component supported on (1) and the component (B) are added to the polymerization vessel in any order.

Further, for the purpose of allowing the polymerization to proceed smoothly, an antistatic agent, an anti-fouling agent, or the like may be used in combination or supported on a carrier.
The polymerization can be carried out by any of liquid phase polymerization methods such as solution polymerization and suspension polymerization, or gas phase polymerization methods, but suspension polymerization and gas phase polymerization methods are preferably employed from the viewpoint of productivity.

  Specific examples of the inert hydrocarbon medium used in the liquid phase polymerization method include aliphatic hydrocarbons such as propane, butane, pentane, hexane, heptane, octane, decane, dodecane, and kerosene; cyclopentane, cyclohexane, methyl Alicyclic hydrocarbons such as cyclopentane; aromatic hydrocarbons such as benzene, toluene and xylene; halogenated hydrocarbons such as ethylene chloride, chlorobenzene and dichloromethane or mixtures thereof, and the olefin itself. It can also be used as a solvent. In the examples described later, a suspension polymerization method using hexane as an inert hydrocarbon medium was used as a non-limiting example.

When (co) polymerization is performed using the olefin polymerization catalyst as described above, the components (A-1) and (A-2) are usually 10 ⁻¹² to 10 ⁻² mol per liter of reaction volume, Preferably, it is used in such an amount as to be 10 ⁻¹⁰ to 10 ⁻³ mol.

  The component (B-1) used as necessary is a molar ratio of the component (B-1) to the transition metal atom (M) in the components (A-1) and (A-2) [(B- 1) / M] is usually used in an amount of 0.01 to 100,000, preferably 0.05 to 50,000.

  The component (B-2) used as necessary is a molar ratio of the aluminum atom in the component (B-2) to the transition metal atom (M) in the components (A-1) and (A-2). [(B-2) / M] is usually used in an amount of 10 to 500,000, preferably 20 to 100,000.

  The component (B-3) used as necessary is a molar ratio of the component (B-3) to the transition metal atom (M) in the components (A-1) and (A-2) [(B- 3) / M] is usually used in an amount of 1 to 100, preferably 2 to 80.

  When the component (B) is the component (B-1), the molar ratio [(D) / (B-1)] is usually 0.01 to 10, preferably 0.1. When the component (B) is the component (B-2) in such an amount that it becomes ˜5, the molar ratio [(D) / (B-2)] is usually 0.001 to 2, preferably 0.005 to 1. When the component (B) is the component (B-3), the molar ratio [(D) / (B-3)] is usually 0.01 to 10, preferably 0.1 to 5. Used in quantity.

The polymerization temperature is usually in the range of -50 to + 250 ° C, preferably 0 to 200 ° C, particularly preferably 60 to 170 ° C. The polymerization pressure is usually from normal pressure to 100 (kg / cm ² ), preferably from normal pressure to 50 (kg / cm ² ), and the polymerization reaction is batch type (batch type), semi-continuous type, continuous. This can be done in any way of the formula. The polymerization is usually performed in a gas phase or a slurry phase in which polymer particles are precipitated in a solvent. In the case of slurry polymerization or gas phase polymerization, the polymerization temperature is preferably 60 to 90 ° C, more preferably 65 to 85 ° C. By polymerizing in this temperature range, an ethylene polymer having a narrower composition distribution can be obtained.

  The ethylene polymer (α) of the present invention may have an elution curve in gel permeation chromatography (GPC) which may be unimodal or multimodal. However, a multimodal ethylene polymer is preferred from the viewpoint that it is easy to tune the numerical values of each requirement within the claims of the requirements [a] to [g] according to the present invention.

  In the multimodal ethylene polymer, two or more kinds of polymers are separately produced in different polymerizers, and then these plural polymers satisfy the above-mentioned requirements that the ethylene polymer (α) of the present invention should satisfy. It may be prepared by blending, or after the first stage polymerization in the same polymerization vessel, the second stage polymerization may be carried out and adjusted, or two or more stages arranged in series with different reaction conditions. You may prepare continuously using a polymerization device.

  When the ethylene polymer (α) of the present invention is prepared in two stages using, for example, the same polymerization apparatus in two stages, or in two stages using two or more series arrangement type polymerization apparatuses having different reaction conditions, An ethylene homopolymer having an intrinsic viscosity of 0.6 to 2.0 (dl / g), preferably 0.9 to 1.9 (dl / g) in the first-stage polymerization vessel is 50 to 75 wt. %, Preferably 55 to 70% by weight of ethylene copolymer having an intrinsic viscosity of 5.5 to 15 (dl / g), preferably 6.5 to 13 (dl / g) in the second stage polymerization vessel Is produced in an amount of 25 to 50% by weight, preferably 30 to 45% by weight. The order of producing the ethylene homopolymer and the ethylene copolymer may be reversed, but the ethylene homopolymer is used in that the ethylene resin composition for the hollow molded body of the present invention should be easily controlled. The prescription manufactured first is preferred.

  The intrinsic viscosity of the high molecular weight polymer of the ethylene copolymer polymerized by the transition metal compound (A-2) in the second stage polymerizer is 10 to 40 (dl / g), preferably 10 to 30 (dl / g). g), particularly preferably 13 to 25 (dl / g), and the polymerization amount of the high molecular weight polymer of the ethylene copolymer polymerized in the second stage polymerization vessel by the transition metal compound (A-2) is It is 3 to 15% by weight of the total amount, preferably 4 to 10% by weight.

  The intrinsic viscosity of the high molecular weight polymer of the ethylene copolymer polymerized by the transition metal compound (A-1) in the second stage polymerizer is 4 to 9.5 (dl / g), preferably 6 to 9. 5 (dl / g).

  The intrinsic viscosity and polymerization amount of the high molecular weight polymer of the ethylene copolymer polymerized in the second stage polymerization vessel of the transition metal compound (A-2), and the second stage by the transition metal compound (A-1) When the intrinsic viscosity of the high molecular weight polymer of the ethylene copolymer polymerized in the polymerization vessel is in the above range, it has excellent elongation flow characteristics, large swell, suppresses the occurrence of poor dispersion, and the pinch-off part of the parison bond part is good. It becomes.

The polymerization amount ratio of the ethylene copolymer polymerized in the second stage polymerization vessel of the transition metal compound (A-1) and the transition metal compound (A-2) is as follows when each metallocene compound is polymerized alone. It is determined by the polymerization activity ratio of the second stage high molecular weight polymer. The polymerization amount of the high molecular weight polymer in the second stage is such that the homopolymerization activity (second stage) of each transition metal compound is δ for the transition metal compound (A-1) and ε (for the transition metal compound (A-2)). (Second stage polymerization amount: (A-1) second stage polymerization amount: wt%) = (second stage polymerization amount: wt%) _{(ethylene composition)} × δ / (δ + ε ), And (second-stage polymerization amount of component (A-2): wt%) = (second-stage polymerization amount: wt%) _{(ethylene composition)} × ε / (δ + ε) I can do it. However, the homopolymerization activity in the second stage is the polymerization activity that received the history of the first stage.

The intrinsic viscosity of the high molecular weight polymer of the ethylene copolymer polymerized in the second stage polymerization vessel of the transition metal compound (A-1) and the transition metal compound (A-2) is obtained by polymerizing each metallocene compound alone. It is determined by the intrinsic viscosity of the second stage high molecular weight polymer. The intrinsic viscosity of the second stage is [η] _{(ethylene composition)} = ([η] _{(first stage composition)} × (first stage polymerization amount: wt%) + [η] _{(second stage Composition)} x (second-stage polymerization amount:% by weight)) / 100.

  In a preferred preparation method using the fine particle carrier (C), the polymer obtained is usually in the form of particles of about several tens to several thousand μmφ. When the polymerization is carried out in a continuous system comprising two or more polymerization vessels, it may be necessary to perform an operation such as dissolution in a good solvent and precipitation in a poor solvent, or sufficient melting and kneading with a specific kneader.

  The molecular weight of the resulting ethylene polymer particles can be adjusted by allowing hydrogen molecules to exist in the polymerization system or changing the polymerization temperature. Furthermore, it can also adjust by the difference in the component (B) to be used.

The polymer particles obtained by the polymerization reaction are usually pelletized by the following method.
(1) A method of mechanically blending ethylene-based polymer particles and other components added as required using an extruder, a kneader, etc., and cutting them into a predetermined size.

  (2) Dissolve the ethylene polymer particles and other components added as required in a suitable good solvent (for example, a hydrocarbon solvent such as hexane, heptane, decane, cyclohexane, benzene, toluene and xylene), and then a solvent And then blended mechanically using an extruder, kneader, etc., and cut to a predetermined size.

  In addition, when the ethylene polymer (α) of the present invention is composed of two or more kinds of ethylene polymers, in the above (1) or (2), two or more kinds of ethylene polymers are used as the ethylene polymers. May be used in combination.

The ethylene-based polymer (α) of the present invention is particularly preferable for hollow body molding described later.
The ethylene polymer (α) of the present invention has a weather resistance stabilizer, heat resistance stabilizer, antistatic agent, anti-slip agent, anti-blocking agent, anti-fogging agent, lubricant, as long as the object of the present invention is not impaired. Additives such as dyes, nucleating agents, plasticizers, anti-aging agents, hydrochloric acid absorbents, antioxidants, carbon black, titanium oxide, titanium yellow, phthalocyanine, isoindolinone, quinacridone compounds, condensed azo compounds, ultramarine, cobalt blue Etc. may be blended if necessary.

<Hollow molding>
The hollow molded article of the present invention is composed of the ethylene polymer (α) of the present invention, and preferred embodiments as the hollow molded article are a fuel tank, a drum can, an agricultural chemical container, IBC, and a container.

  The hollow molded body of the present invention is a hollow molded body including a layer made of the ethylene polymer (α) of the present invention. That is, the hollow molded body of the present invention may be formed of a single layer like a single layer container, or may be formed of two or more layers like a multilayer container, and the wall thickness is It can be arbitrarily changed in the range of 100 μm to 5 mm depending on the application.

  For example, when the multilayer container is formed of two layers, the first layer is formed of the above-described ethylene polymer (α) of the present invention, and the other layer forms the first layer of the present invention. Or an ethylene polymer (α) of the present invention, which is used in the first layer. It can also be formed from an ethylene polymer (α) having physical properties different from those of the polymer.

  Examples of the above-mentioned “different polymers” include polyamide (nylon 6, nylon 66, nylon 12, copolymer nylon, etc.), ethylene / vinyl alcohol copolymer, polyester (polyethylene terephthalate, etc.), and modified polyolefin. it can. Of these, an ethylene / vinyl alcohol copolymer and a polyamide resin having a gas barrier function that is not expressed in polyethylene are preferably used. At that time, in order to increase the interlayer adhesion strength, a layer of gas barrier resin such as ethylene / vinyl alcohol copolymer or polyamide resin is laminated and integrated with the above-mentioned polyethylene resin layer through the adhesive resin layer. The above arrangement is preferable, whereby a container excellent in impact resistance and gas barrier property can be manufactured. As the adhesive resin, an adhesive polyolefin resin is preferable. For example, a carboxylic acid graft-modified polyolefin or a metal ion cross-linked product of an ethylene / unsaturated carboxylic acid copolymer can be used.

Preferred embodiments of the hollow molded article of the present invention are a fuel tank, a drum can, and an agrochemical container.
More preferred embodiments of the fuel tank and the agricultural chemical container of the present invention are as follows. From the inside toward the outside, the ethylene polymer (α) layer (I) / adhesive layer (IV) / the barrier layer (II) of the present invention. / Fuel tank and agrochemical container including a laminated structure composed of a regeneration layer (III).

  In the fuel tank and agricultural chemical container of the present invention, the ethylene polymer (α) layer (I) and the barrier layer (II) are preferably laminated via an adhesive layer (IV). It is also preferable that the layer (III) and the barrier layer (II) are laminated via an adhesive layer.

  That is, the fuel tank and agricultural chemical container of the present invention are more preferably an ethylene polymer (α) layer (I) / adhesive layer (IV) / barrier layer (II) / adhesive layer (IV) / regeneration layer ( III) / Laminated structure composed of ethylene polymer (α) layer (I). The regenerated layer is known as a pulverized regenerated layer, and is preferably manufactured from so-called burrs that are generated in the form of material residues in the manufacturing process of the hollow plastic product.

  The hollow molded body of the present invention is prepared by a conventionally known hollow molding (blow molding) method. There are various blow molding methods, which are roughly classified into extrusion blow molding, two-stage blow molding, and injection molding. In the present invention, an extrusion blow molding method and an injection molding method are particularly preferably employed.

EXAMPLES Hereinafter, although this invention is demonstrated further more concretely based on an Example, this invention is not limited to these Examples.
[Measurement of ethylene polymer (α)]
The measuring method of the physical property of an ethylene-type polymer and an ethylene-type polymer ((alpha)) is shown below.

<Melt flow rate (MFR)>
According to JIS K7210 (1999), the measurement was performed under the conditions of 190 ° C., 2.16 kg load and 190 ° C., 21.6 kg load.

<Density (d)>
In accordance with JIS K7112 (1999), the strand obtained at the time of MFR measurement was heat-treated at 100 ° C. for 1 hour, and further allowed to stand at room temperature for 1 hour, and then measured by a density gradient tube method.

<Melting tension (MT)>
The melt tension (MT) at 190 ° C. (unit: g) was determined by measuring the stress when stretched at a constant speed. For the measurement, a capillary rheometer: Capillograph 1B manufactured by Toyo Seiki Seisakusho was used. The conditions were a resin temperature of 190 ° C., a melting time of 6 minutes, a barrel diameter of 9.55 mmφ, an extrusion speed of 15 mm / min, a winding speed of 7.85 m / min, a die diameter of 2.095 mmφ, and a die length of 8 mm. It can be said that as this value is larger, drawdown during hollow molding is suppressed and moldability is better.

<Intrinsic viscosity [η]>
About 20 mg of a measurement sample was dissolved in 15 ml of decalin, and the specific viscosity η _sp was measured in an oil bath at 135 ° C. After adding 5 ml of decalin solvent to the decalin solution for dilution, the specific viscosity η _sp was measured in the same manner. This dilution operation was further repeated twice, and the value of η _sp / C when the concentration (C) was extrapolated to 0 as shown in the following formula (Eq-6A) was expressed as the intrinsic viscosity [η] (unit: dl / g ).
[Η] = lim (η _sp / C) (C → 0) -------- (Eq-6A)

<Number average molecular weight (Mn), weight average molecular weight (Mw), Z average molecular weight (Mz), Z + 1 average molecular weight (Mz + 1), molecular weight distribution (Mw / Mn, Mz / Mw, Mz + 1 / Mw)>
The molecular weight distribution curve was measured as follows using a gel permeation chromatograph alliance GPC2000 (high temperature size exclusion chromatograph) manufactured by Waters.
Analysis software: Chromatography data system Empower2 (Waters)
Column: TSKgel GMH ₆ -HT × 2 + TSKgel GMH ₆ -HTL × 2 (inner diameter 7.5 mm × length 30 cm, Tosoh Corporation)
Mobile phase: o-dichlorobenzene (Wako Pure Chemicals special grade reagent)
Detector: Differential refractometer (built-in device)
Column temperature: 140 ° C
Flow rate: 1.0 mL / min Injection volume: 500 μL
Sampling time interval: 1 second Sample concentration: 0.15% (w / v)
Molecular weight calibration: monodisperse polystyrene (Tosoh Corporation) / molecular weight 495 to 20.6 million

Z. Crubisic, P.M. Rempp, H.M. Benoit, J.M. Polym. Sci. , B5 , 753 (1967), universal calibration was performed, and the number average molecular weight (Mn), weight average molecular weight (Mw), Z average molecular weight (Mz), as standard polyethylene molecular weight conversion, Z + 1 average molecular weight (Mz + 1) and molecular weight distribution (Mw / Mn, Mz / Mw, Mz + 1 / Mw) were determined.

<Shear pressure (σ) at 210 ° C.>
The apparent shear pressure (σ) (unit: Pa) at 210 ° C. was determined by measuring the pressure when extruded at a constant speed. For the measurement, a capillary rheometer: Capillograph 1B manufactured by Toyo Seiki Seisakusho was used. The conditions were a resin temperature of 210 ° C., a barrel diameter of 9.55 mmφ, an extrusion rate of 200 mm / min (apparent shear rate of 19460 s ⁻¹ ), a capillary length L of 5.0 mmφ, and a diameter of 0.5 mm. .
It can be said that the larger this value, the better the elongational flow characteristics.

<Swell ratio>
The swell ratio at 230 ° C. was evaluated with a capillary rheometer manufactured by Toyo Seiki Seisakusho.
Measurement was performed using a die having a barrel diameter of 9.55 mm, a thin tube length L of 3.0 mm, a diameter of 0.5 mm, and an inflow angle of 90 °.

  The sample was extruded at a cylinder temperature of 230 ° C. and a piston descending speed of 1 mm / min, 2 mm / min, and 5 mm / min, and when the piston descending speed was 2 mm / min, the strand diameter 17 mm below the nozzle outlet (D i ) Was measured with a laser beam. The ratio (swell ratio = D i / D 0) between the strand diameter (D i) and the nozzle diameter (D 0) thus measured was determined.

[Method for molding ethylene polymer (α), measurement of physical properties of hollow body]
<Hollow molding conditions>
Using an NB-30 hollow molding machine manufactured by Nippon Steel Works, a hollow container was molded by an accumulator type, and the appearance was evaluated. Cylinder set temperature: 210 ° C, die set temperature: 210 ° C, mold temperature: 20 ° C, injection speed: 0.1625kg / s, die diameter: 132mm, die gap: 5.25mm The outer appearance of the inner and outer surfaces of the parison was evaluated.
Also, the pinch shape of the molded bottle was confirmed by changing the gap of the die core according to the sample so that a 20L hand-held square-shaped chemical can (bottle weight 1000g) was formed.

<Product skin / pinch shape>
Check the appearance of the parison and the pinch shape of the bottle visually.
a) A parison that has no sharkskin or nail and has a good appearance and a good pinch shape.
b) There is no sharkskin in the parison, but the one with a bad shape or pinch shape
c) What causes sharkskin in a parison ×
It was.

[Example 1]
[Synthesis Example 1]
[Preparation of solid carrier (X-1)]
After 5 g of silica (average particle size = 3.8 μm, specific surface area = 804 m ² / g, pore volume = 0.87 mL / g) dried at 200 ° C. for 3 hours was suspended in 274 ml of toluene, methyl Aluminoxane solution (Al = 3.03 mol / liter) 33.0 ml was added dropwise over 30 minutes. Next, the temperature was raised to 100 ° C. over 1.5 hours, and the reaction was carried out at that temperature for 4 hours. Thereafter, the temperature was lowered to 60 ° C., and the supernatant was removed by a decantation method. The obtained solid catalyst component was washed with toluene three times and then resuspended with toluene to obtain a solid catalyst component (X-1) (total volume: 257 ml).

[Synthesis Example 2]
[Preparation of solid catalyst component (Y-1) by supporting metallocene compound]
A 500 mL glass container equipped with a magnetic stirrer and fully purged with nitrogen was charged with 149.7 mL of dehydrated toluene, and 54.28 mL of toluene slurry of the solid support (X-1) prepared above (21 in terms of Al atoms). .12 mmol) was charged. Next, 17.60 mL of a toluene solution of a transition metal complex represented by di (p-tolyl) methylene (cyclopentadienyl) (octamethyloctahydrodibenzofluorenyl) zirconium dichloride (A-1) (in terms of Zr atom) 0.047 mmol) was added dropwise, and 15 minutes later, 28.41 mL (0.026 mmol in terms of Zr atom) of a transition metal complex represented by A-2 was added dropwise and reacted at room temperature for 1 hour. The olefin polymerization catalyst (Y-1) was obtained.

<Ethylene polymer (α-1)>
250 L of purified heptane was placed in a polymerization tank having an internal volume of 500 liters sufficiently purged with nitrogen, and 89 mmol of triisobutylaluminum and 2.38 g of olefin polymerization catalyst (Y-1) were added thereto in terms of solid components. After raising the temperature to 80 ° C. and depressurizing once, ethylene / hydrogen mixed gas (concentration of gas phase: hydrogen / ethylene = 0.100 (mol / mol)) is continuously applied to 0.65 MPa · G. The polymerization was carried out for 1.9 hours. After the polymerization, the pressure was released, and nitrogen substitution was performed to remove the used ethylene / hydrogen mixed gas. The obtained polymer had a density of 963 (kg / m ³ ), [η] of 1.76 (dl / g), MFR of 2.01 g / 10 min, and the polymerization amount of the polymer was 23.7 kg. there were.

  After inserting 60 mmol of triisobutylaluminum and 194 ml of 1-hexene into this polymerization tank, raising the temperature to 75 ° C. and depressurizing it once, then continuously supplying an ethylene / hydrogen mixed gas to 0.30 MPa · G. (Concentration in gas phase: hydrogen / ethylene = 0.0091 (mol / mol)), polymerization was carried out for 2.1 hours.

Methanol was added to the polymerization tank to stop the reaction, and cooling and residual gas were purged. The obtained ethylene polymer (PE) slurry was filtered. The ethylene polymer was dried under reduced pressure at 80 ° C. for 10 hours. The obtained ethylene polymer was 36.4 kg, the polymerization activity was 124.7 kg-PE / mmol-Zr · hr, and the productivity was 3860 g-PE / g-cat. · Hr. As a result of the analysis of the ethylene polymer, a powder having a bulk density of 0.479 g / cm ³ , a polymer density = 952 g / cm ³ , and an intrinsic viscosity [η] of 3.99 dL / g was obtained. The same operation was performed 3 times.

  As a heat-resistant stabilizer, Irganox 1010 (manufactured by Ciba Specialty Chemicals Co., Ltd.) 1000 ppm and Irgafos168 (manufactured by Ciba Specialty Chemicals Co., Ltd.) 1000 ppm calcium stearate (manufactured by Nitto Kasei Kogyo Co., Ltd.) 1500 ppm were added to 100 parts by weight of the powder. After that, using a single screw extruder (screw diameter 65mm, L / D = 28, screen mesh 40/60/100/60/40) manufactured by Plako, set temperature 240 ° C, resin extrusion rate 25 (kg / hr) After melt-kneading under conditions, it was extruded into a strand shape and cut to obtain an ethylene polymer (α-1) pellet. Table 1 shows the results of measuring physical properties of the obtained pellets as measurement samples. Furthermore, hollow molding was implemented using the obtained pellet. Table 1 shows the product skin at the time of molding.

[Example 2]
[Synthesis Example 3]
[Preparation of solid carrier (X-2)]
9.0 kg of silica dried for 3 hours at 200 ° C. (average particle size = 3.8 μm, specific surface area = 804 m ² / g, pore volume = 0.87 mL / g) was suspended in 49.4 liters of toluene. After that, 59.4 liters of methylaluminoxane solution (Al = 3.03 mol / liter) was added dropwise over 30 minutes. Next, the temperature was raised to 100 ° C. over 1.5 hours, and the reaction was performed at that temperature for 4 hours. Thereafter, the temperature was lowered to 60 ° C., and the supernatant was removed by a decantation method. The obtained solid catalyst component was washed with toluene three times and then resuspended with toluene to obtain a solid catalyst component (X-2) (total volume 118 liters).

[Synthesis Example 4]
[Preparation of solid catalyst component (Y-2) by supporting metallocene compound]
In a reaction vessel sufficiently purged with nitrogen, 18.01 mol of the solid carrier (X-2) synthesized in Synthesis Example 1 suspended in toluene was converted into aluminum atoms, and the suspension was stirred. Then, 2 liters (40.38 mmol) of the compound (A-1) 20.18 (mmol / liter) solution was added at room temperature (20 to 25 ° C.) and reacted for 0.25 hour. 2) (13.46 mmol) of a 6.73 (mmol / liter) solution was added to obtain an olefin polymerization catalyst (Y-2).

<Ethylene polymer (α-2)>
In a first polymerization tank equipped with a stirrer with an internal volume of 340 L, hexane was converted to 29 (liter / hr), olefin polymerization catalyst (Y-2) was converted to zirconium atoms, 0.027 (mmol / hr), ethylene 6.0 ( kg / hr), hydrogen 26.7 (N-liter / hr), and triisobutylaluminum 8.1 (mmol / hr) were continuously supplied. Adekapronic L-71 (manufactured by ADEKA Corporation, hereinafter referred to as L) -71) (continuous supply of 0.46 (g / hr) and the polymerization content is continuously withdrawn so that the liquid level in the polymerization tank becomes constant, the polymerization temperature is 80 ° C., the reaction pressure is 0 Polymerization was conducted under the conditions of 0.52 (MPaG) and an average residence time of 3.7 hours.

The contents continuously extracted from the first polymerization tank were subjected to removal of unreacted ethylene and hydrogen in a flash drum maintained at an internal pressure of 0.30 (MPaG) and 60 ° C.
Thereafter, the content, hexane 26 (liter / hr), triisobutylaluminum 6.2 (mmol / hr), ethylene 3.2 (kg / hr), hydrogen molecules into a second polymerization tank with an internal volume of 200 L equipped with a stirrer 0.8 (N-liter / hr), 1-hexene 25 (g / hr), L-71 0.24 (g / hr) are continuously supplied, and the liquid level in the polymerization tank is constant. Polymerization was carried out under the conditions of a polymerization temperature of 75 ° C., a reaction pressure of 0.30 (MPaG), and an average residence time of 2.1 hours while continuously extracting the polymerization contents so that

Methanol was supplied to the content extracted from the second polymerization tank at 2 (liter / hr) to deactivate the polymerization catalyst. Thereafter, hexane and unreacted monomers in the contents were removed with a solvent separator and dried to obtain a polymer. The polymer obtained in the first polymerization tank had a density of 962 (kg / m ³ ), [η] of 1.80 (dl / g), and MFR of 1.83 g / 10 min. The operating conditions were adjusted so that the component polymerized in the first polymerization tank was 65% by weight and the component polymerized in the second polymerization tank was 35% by weight. The density was 953 (kg / m ³ ) and [η] was A powder of 3.88 (dl / g) was obtained.

  As a heat-resistant stabilizer, Irganox 1010 (manufactured by Ciba Specialty Chemicals Co., Ltd.) 1000 ppm and Irgafos168 (manufactured by Ciba Specialty Chemicals Co., Ltd.) 1000 ppm calcium stearate (manufactured by Nitto Kasei Kogyo Co., Ltd.) 1500 ppm were added to 100 parts by weight of the powder. After that, using a single screw extruder (screw diameter 65mm, L / D = 28, screen mesh 40/60/100/60/40) manufactured by Plako, set temperature 240 ° C, resin extrusion rate 25 (kg / hr) After melt-kneading under conditions, it was extruded into a strand shape and cut to obtain an ethylene polymer (α-2) pellet. Table 1 shows the results of measuring physical properties of the obtained pellets as measurement samples. Furthermore, hollow molding was implemented using the obtained pellet. Table 1 shows the product skin at the time of molding.

[Example 3]
[Synthesis Example 5]
[Preparation of solid catalyst component (Y-3) by supporting metallocene compound]
In a reaction vessel sufficiently purged with nitrogen, 18.01 mol of the solid carrier (X-2) synthesized in Synthesis Example 1 suspended in toluene was converted into aluminum atoms, and the suspension was stirred. Then, 2 liters (40.38 mmol) of the compound (A-1) 20.18 (mmol / liter) solution was added at room temperature (20 to 25 ° C.) and reacted for 0.25 hour. ) Was added in 2 liters (17.31 mmol) of an 8.65 (mmol / liter) solution to obtain an olefin polymerization catalyst (Y-3).

<Ethylene polymer (α-3)>
In a first polymerization tank with an internal volume of 340 L, equipped with a stirrer, hexane 28 (liter / hr), olefin polymerization catalyst (Y-3) in terms of zirconium atoms was 0.037 (mmol / hr), ethylene 6.0 (kg / hr), hydrogen 28.7 (N-liter / hr), triisobutylaluminum 8.1 (mmol / hr), continuously supplied, and L-71 continuously supplied at 0.46 (g / hr). The polymerization was conducted under the conditions of a polymerization temperature of 80 ° C., a reaction pressure of 0.49 (MPaG), and an average residence time of 3.7 hours while continuously extracting the polymerization contents so that the liquid level in the polymerization tank was constant. It was.

The contents continuously extracted from the first polymerization tank were subjected to removal of unreacted ethylene and hydrogen in a flash drum maintained at an internal pressure of 0.30 (MPaG) and 60 ° C.
Thereafter, the contents, hexane 25 (liter / hr), ethylene 3.2 (kg / hr), hydrogen 0.9 (N-liter / hr), 1-hexene were transferred to a second polymerization tank with an internal volume of 200 L equipped with a stirrer. 25 (g / hr), triisobutylaluminum 6.2 (mmol / hr), L-71 0.24 (g / hr) continuously, and the liquid level in the polymerization tank is constant. Polymerization was carried out under the conditions of a polymerization temperature of 75 ° C., a reaction pressure of 0.29 (MPaG), and an average residence time of 2.1 hr while continuously extracting the polymerization contents.

Methanol was supplied to the content extracted from the second polymerization tank at 2 (liter / hr) to deactivate the polymerization catalyst. Thereafter, hexane and unreacted monomers in the contents were removed with a solvent separator and dried to obtain a polymer. The polymer obtained in the first polymerization tank had a density of 963 (kg / m ³ ), [η] of 1.51 (dl / g), and MFR of 4.63 g / 10 min. The operating conditions were adjusted so that the component polymerized in the first polymerization tank was 69% by weight and the component polymerized in the second polymerization tank was 31% by weight. The density was 956 (kg / m ³ ) and [η] was A powder of 3.70 (dl / g) was obtained.

  As a heat-resistant stabilizer, Irganox 1010 (manufactured by Ciba Specialty Chemicals Co., Ltd.) 1000 ppm and Irgafos168 (manufactured by Ciba Specialty Chemicals Co., Ltd.) 1000 ppm calcium stearate (manufactured by Nitto Kasei Kogyo Co., Ltd.) 1500 ppm were added to 100 parts by weight of the powder. After that, using a single screw extruder (screw diameter 65mm, L / D = 28, screen mesh 40/60/100/60/40) manufactured by Plako, set temperature 240 ° C, resin extrusion rate 25 (kg / hr) After melt-kneading under conditions, it was extruded into a strand shape and cut to obtain an ethylene polymer (α-3) pellet. Table 1 shows the results of measuring physical properties of the obtained pellets as measurement samples. Furthermore, hollow molding was implemented using the obtained pellet. Table 1 shows the product skin at the time of molding.

[Example 4]
<Ethylene polymer (α-4)>
In a first polymerization tank with an internal volume of 340 L and equipped with a stirrer, hexane 29 (liter / hr), olefin polymerization catalyst (Y-3) in terms of zirconium atoms was converted to 0.034 (mmol / hr), ethylene 5.2 (kg / hr), hydrogen 30.1 (N-liter / hr), triisobutylaluminum 8.1 (mmol / hr), L-71 0.44 (g / hr) was continuously fed, and the polymerization tank Polymerization was carried out under conditions of a polymerization temperature of 80 ° C., a reaction pressure of 0.42 (MPaG), and an average residence time of 3.8 hr while continuously extracting the polymerization contents so that the liquid level in the inside was constant.

The contents continuously extracted from the first polymerization tank were subjected to removal of unreacted ethylene and hydrogen in a flash drum maintained at an internal pressure of 0.30 (MPaG) and 60 ° C.
Thereafter, the contents, hexane 25 (liter / hr), ethylene 4.0 (kg / hr), hydrogen molecule 1.4 (N-liter / hr), 1− Continuous supply of hexene 25 (g / hr), triisobutylaluminum 6.2 (mmol / hr), L-71 0.26 (g / hr), and the liquid level in the polymerization tank is constant. Polymerization was carried out under the conditions of a polymerization temperature of 75 ° C., a reaction pressure of 0.37 (MPaG), and an average residence time of 2.1 hours while continuously extracting the polymerization contents.

Methanol was supplied to the content extracted from the second polymerization tank at 2 (liter / hr) to deactivate the polymerization catalyst. Thereafter, hexane and unreacted monomers in the contents were removed with a solvent separator and dried to obtain a polymer. The polymer obtained in the first polymerization tank had a density of 963 (kg / m ³ ), [η] of 1.58 (dl / g), and MFR of 3.02 g / 10 min. The operating conditions were adjusted so that the component polymerized in the first polymerization tank was 65% by weight and the component polymerized in the second polymerization tank was 35% by weight. The density was 953 (kg / m ³ ) and [η] was 3. 80 (dl / g) powder was obtained.

  As a heat-resistant stabilizer, Irganox 1010 (manufactured by Ciba Specialty Chemicals Co., Ltd.) 1000 ppm and Irgafos168 (manufactured by Ciba Specialty Chemicals Co., Ltd.) 1000 ppm calcium stearate (manufactured by Nitto Kasei Kogyo Co., Ltd.) 1500 ppm were added to 100 parts by weight of the powder. After that, using a single screw extruder (screw diameter 65mm, L / D = 28, screen mesh 40/60/100/60/40) manufactured by Plako, set temperature 240 ° C, resin extrusion rate 25 (kg / hr) After melt-kneading under conditions, it was extruded into a strand shape and cut to obtain an ethylene polymer (α-4) pellet. Table 1 shows the results of measuring physical properties of the obtained pellets as measurement samples. Furthermore, hollow molding was implemented using the obtained pellet. Table 1 shows the product skin at the time of molding.

[Example 5]
<Ethylene polymer (α-5)>
In a first polymerization tank with an internal volume of 340 L, equipped with a stirrer, hexane 28 (liter / hr), olefin polymerization catalyst (Y-3) in terms of zirconium atoms was 0.037 (mmol / hr), ethylene 6.0 (kg / hr), hydrogen 28.7 (N-liter / hr), triisobutylaluminum 8.1 (mmol / hr), continuously supplied, and L-71 continuously supplied at 0.46 (g / hr). The polymerization was conducted under the conditions of a polymerization temperature of 80 ° C., a reaction pressure of 0.49 (MPaG), and an average residence time of 3.7 hours while continuously extracting the polymerization contents so that the liquid level in the polymerization tank was constant. It was.

The contents continuously extracted from the first polymerization tank were subjected to removal of unreacted ethylene and hydrogen in a flash drum maintained at an internal pressure of 0.30 (MPaG) and 60 ° C.
Thereafter, the contents, hexane 25 (liter / hr), ethylene 3.2 (kg / hr), hydrogen 0.9 (N-liter / hr), 1-hexene were transferred to a second polymerization tank with an internal volume of 200 L equipped with a stirrer. 40 (g / hr), triisobutylaluminum is continuously supplied at 6.2 (mmol / hr), L-71 is continuously supplied at 0.24 (g / hr), and the liquid level in the polymerization tank becomes constant. In this way, the polymerization was carried out under the conditions of a polymerization temperature of 75 ° C., a reaction pressure of 0.29 (MPaG), and an average residence time of 2.1 hours while continuously extracting the polymerization contents.

Methanol was supplied to the content extracted from the second polymerization tank at 2 (liter / hr) to deactivate the polymerization catalyst. Thereafter, hexane and unreacted monomers in the contents were removed with a solvent separator and dried to obtain a polymer. The polymer obtained in the first polymerization tank had a density of 963 (kg / m ³ ), [η] of 1.51 (dl / g), and MFR of 4.61 g / 10 min. The operating conditions were adjusted so that the component polymerized in the first polymerization tank was 69% by weight and the component polymerized in the second polymerization tank was 31% by weight. The density was 951 (kg / m ³ ) and [η] was A powder of 3.70 (dl / g) was obtained.

  As a heat-resistant stabilizer, Irganox 1010 (manufactured by Ciba Specialty Chemicals Co., Ltd.) 1000 ppm and Irgafos168 (manufactured by Ciba Specialty Chemicals Co., Ltd.) 1000 ppm calcium stearate (manufactured by Nitto Kasei Kogyo Co., Ltd.) 1500 ppm were added to 100 parts by weight of the powder. After that, using a single screw extruder (screw diameter 65mm, L / D = 28, screen mesh 40/60/100/60/40) manufactured by Plako, set temperature 240 ° C, resin extrusion rate 25 (kg / hr) After melt-kneading under the conditions, it was extruded into a strand shape and cut to obtain ethylene polymer (α-5) pellets. Table 1 shows the results of measuring physical properties of the obtained pellets as measurement samples. Furthermore, hollow molding was implemented using the obtained pellet. Table 1 shows the product skin at the time of molding.

[Comparative Example 1]
[Synthesis Example 6]
[Preparation of solid catalyst component (Y-4) by supporting metallocene compound]
In a reaction vessel sufficiently purged with nitrogen, 18.01 mol of the solid catalyst (X-2) synthesized in Synthesis Example 1 suspended in toluene was converted into aluminum atom, and the suspension was stirred. Then, 2 liters (61.12 mmol) of the compound (A-1) 31.06 (mmol / liter) solution was added at room temperature (20 to 25 ° C.) and allowed to react for 1 hour to prepare an olefin polymerization catalyst (Y-4). Obtained.

<Ethylene polymer (β-1)>
In a first polymerization tank with an internal volume of 340 L and equipped with a stirrer, hexane 51 (liter / hr), olefin polymerization catalyst (Y-4) in terms of zirconium atom is 0.027 (mmol / hr), ethylene 7.8 (kg / hr), hydrogen 29.1 (N-liter / hr), triisobutylaluminum 11.2 (mmol / hr), L-71 0.46 (g / hr) was continuously fed, and the polymerization tank Polymerization was carried out under the conditions of a polymerization temperature of 80 ° C., a reaction pressure of 0.75 (MPaG), and an average residence time of 2.7 hr while continuously extracting the polymerization contents so that the liquid level in the inside was constant.

The contents continuously extracted from the first polymerization tank were subjected to removal of unreacted ethylene and hydrogen in a flash drum maintained at an internal pressure of 0.30 (MPaG) and 60 ° C.
Thereafter, the contents, hexane 26 (liter / hr), ethylene 4.2 (kg / hr), hydrogen 0.7 (N-liter / hr), 1-hexene were transferred to a second polymerization tank with an internal volume of 200 L equipped with a stirrer. 35 (g / hr), triisobutylaluminum is 7.2 (mmol / hr), L-71 is continuously fed at 0.24 (g / hr), and the liquid level in the polymerization tank is constant. In this way, the polymerization was carried out under the conditions of a polymerization temperature of 75 ° C., a reaction pressure of 0.26 (MPaG), and an average residence time of 1.6 hours while continuously extracting the polymerization contents.

Methanol was supplied to the content extracted from the second polymerization tank at 2 (liter / hr) to deactivate the polymerization catalyst. Thereafter, hexane and unreacted monomers in the contents were removed with a solvent separator and dried to obtain a polymer. The polymer obtained in the first polymerization tank had a density of 965 (kg / m ³ ), [η] of 1.17 (dl / g), and MFR of 13 g / 10 min. The operating conditions were adjusted so that the component polymerized in the first polymerization tank was 65% by weight and the component polymerized in the second polymerization tank was 35% by weight. The density was 953 (kg / m ³ ) and [η] was A powder of 3.55 dl / g) was obtained.

  As a heat-resistant stabilizer, Irganox 1010 (manufactured by Ciba Specialty Chemicals Co., Ltd.) 1000 ppm and Irgafos168 (manufactured by Ciba Specialty Chemicals Co., Ltd.) 1000 ppm calcium stearate (manufactured by Nitto Kasei Kogyo Co., Ltd.) 1500 ppm were added to 100 parts by weight of the powder. After that, using a single screw extruder (screw diameter 65mm, L / D = 28, screen mesh 40/60/100/60/40) manufactured by Plako, set temperature 240 ° C, resin extrusion rate 25 (kg / hr) After melt-kneading under conditions, it was extruded into a strand shape and cut to obtain an ethylene polymer (β-1) pellet. Table 1 shows the results of measuring physical properties of the obtained pellets as measurement samples. Furthermore, hollow molding was implemented using the obtained pellet. Table 1 shows the product skin at the time of molding.

Ethylene polymer of Comparative Example 1, the shear rate at 210 ° C. of the ethylene-based polymer (β-1) 19460s ^- pressure at ¹ (sigma, Pa) is smaller than the right side of the requirements [c]. For this reason, the appearance defect of the shark skin occurred on the product skin.

[Comparative Example 2]
<Ethylene polymer (β-2)>
In a first polymerization tank with an internal volume of 340 L equipped with a stirrer, hexane 51 (liter / hr), olefin polymerization catalyst (Y-4) in terms of zirconium atoms was converted to 0.027 (mmol / hr), and ethylene was 7.2 ( kg / hr), hydrogen 26.1 (N-liter / hr), triisobutylaluminum 11.2 (mmol / hr) L-71 0.46 (g / hr) were continuously fed and polymerized. Polymerization was performed under the conditions of a polymerization temperature of 80 ° C., a reaction pressure of 0.75 (MPaG), and an average residence time of 2.7 hr while continuously extracting the polymerization contents so that the liquid level in the tank was constant.

The contents continuously extracted from the first polymerization tank were subjected to removal of unreacted ethylene and hydrogen in a flash drum maintained at an internal pressure of 0.30 (MPaG) and 60 ° C.
Thereafter, the contents, hexane 26 (liter / hr), ethylene 4.8 (kg / hr), hydrogen 0.8 (N-liter / hr), 1-hexene were transferred to a second polymerization tank with an internal volume of 200 L equipped with a stirrer. 35 (g / hr), triisobutylaluminum is 7.2 (mmol / hr), L-71 is continuously fed at 0.24 (g / hr), and the liquid level in the polymerization tank is constant. In this way, the polymerization was carried out under the conditions of a polymerization temperature of 75 ° C., a reaction pressure of 0.26 (MPaG), and an average residence time of 1.6 hours while continuously extracting the polymerization contents.

Methanol was supplied to the content extracted from the second polymerization tank at 2 (liter / hr) to deactivate the polymerization catalyst. Thereafter, hexane and unreacted monomers in the contents were removed with a solvent separator and dried to obtain a polymer. The polymer obtained in the first polymerization tank had a density of 964 (kg / m ³ ), [η] of 1.34 (dl / g), and MFR of 7.2 g / 10 min. The operating conditions were adjusted so that the component polymerized in the first polymerization tank was 60% by weight and the component polymerized in the second polymerization tank was 40% by weight. The density was 952 (kg / m ³ ) and [η] was A powder of 3.46 (dl / g) was obtained.

  As a heat-resistant stabilizer, Irganox 1010 (manufactured by Ciba Specialty Chemicals Co., Ltd.) 1000 ppm and Irgafos168 (manufactured by Ciba Specialty Chemicals Co., Ltd.) 1000 ppm calcium stearate (manufactured by Nitto Kasei Kogyo Co., Ltd.) 1500 ppm were added to 100 parts by weight of the powder. After that, using a single screw extruder (screw diameter 65mm, L / D = 28, screen mesh 40/60/100/60/40) manufactured by Plako, set temperature 240 ° C, resin extrusion rate 25 (kg / hr) After melt-kneading under conditions, it was extruded into a strand shape and cut to obtain an ethylene polymer (β-2) pellet. Table 1 shows the results of measuring physical properties of the obtained pellets as measurement samples. Furthermore, hollow molding was implemented using the obtained pellet. Table 1 shows the product skin at the time of molding.

In the ethylene polymer of Comparative Example 2, the pressure (σ, Pa) at a shear rate of 19460 s ^-1 at 210 ° C. of the ethylene polymer (β-2) is smaller than the right side of the requirement [c]. For this reason, the appearance defect of the shark skin occurred on the product skin.

[Comparative Example 3]
[Synthesis Example 7]
[Preparation of solid catalyst component (Y-5) by supporting transition metal complex]
A 500 mL glass container equipped with a magnetic stirrer and sufficiently purged with nitrogen was charged with 142.7 mL of dehydrated toluene, and 43.00 mL of the toluene slurry of the solid carrier (X-1) prepared above was 16 (in terms of Al atoms). .74 mmol) was charged. Subsequently, 64.30 mL (0.058 mmol in terms of Zr atom) of a toluene solution of the transition metal complex represented by A-2 was dropped and reacted at room temperature for 1 hour to obtain an olefin polymerization catalyst (Y-5). It was.

<Ethylene polymer (β-3)>
Purified heptane (250 L) was placed in a polymerization tank having an internal volume of 500 liters sufficiently purged with nitrogen, and 89 mmol of triisobutylaluminum and a catalyst for olefin polymerization (Y-5) were added thereto in terms of solid components. After raising the temperature to 80 ° C. and depressurizing once, ethylene / hydrogen mixed gas (concentration of gas phase: hydrogen / ethylene = 0.120 (mol / mol)) is continuously applied to 0.50 MPa · G. The polymerization was conducted for 2.5 hours. After the polymerization, the pressure was released, and nitrogen substitution was performed to remove the used ethylene / hydrogen mixed gas. The obtained polymer had a density of 964 (kg / m ³ ), [η] of 1.36 (dl / g), MFR of 6.42 g / 10 min, and a polymer polymerization amount of 22.4 kg. It was.

  In this polymerization tank, 60 mmol of triisobutylaluminum and 194 ml of 1-hexene were inserted, the temperature was raised to 75 ° C. and the pressure was released once. Then, an ethylene / hydrogen mixed gas was continuously supplied so that the pressure became 0.65 MPa · G. (Concentration of gas phase part: hydrogen / ethylene = 0.011 (mol / mol)), polymerization was carried out for 1.4 hours.

Methanol was added to the polymerization tank to stop the reaction, and cooling and residual gas were purged. The obtained ethylene polymer (PE) slurry was filtered. The ethylene polymer was dried under reduced pressure at 80 ° C. for 10 hours. The obtained ethylene polymer was 34.5 kg, the polymerization activity was 152.5 kg-PE / mmol-Zr · hr, and the productivity was 4760 g-PE / g-cat. · Hr. As a result of analysis of the ethylene polymer, a powder having a bulk density of 0.453 g / cm ³ , a polymer density of 959 g / cm ³ , and an intrinsic viscosity [η] of 6.19 dL / g was obtained. The same operation was performed 3 times.

  As a heat-resistant stabilizer, Irganox 1010 (manufactured by Ciba Specialty Chemicals Co., Ltd.) 1000 ppm and Irgafos168 (manufactured by Ciba Specialty Chemicals Co., Ltd.) 1000 ppm calcium stearate (manufactured by Nitto Kasei Kogyo Co., Ltd.) 1500 ppm were added to 100 parts by weight of the powder. After that, using a single screw extruder (screw diameter 65mm, L / D = 28, screen mesh 40/60/100/60/40) manufactured by Plako, set temperature 240 ° C, resin extrusion rate 25 (kg / hr) After melt-kneading under conditions, it was extruded into a strand shape and cut to obtain an ethylene polymer (β-3) pellet. Table 1 shows the results of measuring physical properties of the obtained pellets as measurement samples. Furthermore, hollow molding was implemented using the obtained pellet. Table 1 shows the product skin at the time of molding.

  The ethylene polymer of Comparative Example 3 did not generate sharkskin because it satisfied the requirement [c], but the swell ratio of the requirement [e] was small and it was difficult to control the parison molding. In addition, since the Mw / Mn requirement of [h] is not satisfied, there is an inconvenience that the dispersion is inferior, and the pinch-off portion of the parison coupling portion (the fusion portion where the parison is sandwiched between the molds) is thinned. The shape deteriorated.

[Comparative Example 4]
Table 1 shows the results of measuring physical properties in the same manner as in Example 1 except that Tosoh Corporation high-density polyethylene “Nipolon Hard 8900” was used as the ethylene polymer. Further, hollow molding was performed. Table 1 shows the product skin at the time of molding.
Since the ethylene polymer of Comparative Example 4 has a Charpy impact strength (MPa) at −40 ° C. smaller than the right side of the requirement [d], the impact resistance at the time of dropping is insufficient.

[Comparative Example 5]
Table 1 shows the results of measuring physical properties in the same manner as in Example 1 except that Prime Polymer's high-density polyethylene “HI-ZEX8200B” was used as the ethylene polymer. Further, hollow molding was performed. Table 1 shows the product skin at the time of molding.
Since the ethylene polymer of Comparative Example 5 has a Charpy impact strength (MPa) at −40 ° C. smaller than the right side of the requirement [d], the impact resistance at the time of dropping is insufficient.

[Comparative Example 6]
Table 1 shows the results of physical properties measured in the same manner as in Example 1 except that the high-density polyethylene “4261AG” manufactured by Basell was used as the ethylene polymer. Further, hollow molding was performed. Table 1 shows the product skin at the time of molding.
Since the ethylene polymer of Comparative Example 6 has a Charpy impact strength (MPa) at −40 ° C. smaller than the right side of the requirement [d], the impact resistance at the time of dropping is insufficient.

[Comparative Example 7]
Table 1 shows the results of physical properties measured in the same manner as in Example 1 except that high-density polyethylene “HB111R” manufactured by Nippon Polyethylene Co., Ltd. was used as the ethylene polymer. Further, hollow molding was performed. Table 1 shows the product skin at the time of molding.
Since the ethylene polymer of Comparative Example 7 has a Charpy impact strength (MPa) at −40 ° C. smaller than the right side of the requirement [d], the impact resistance at the time of dropping is insufficient.

[Reference Example 1]
[Synthesis Example 8]
[Preparation of solid catalyst component (Y-6) by supporting transition metal compound]
A 500 mL glass container equipped with a magnetic stirrer and fully purged with nitrogen was charged with 149.7 mL of dehydrated toluene, and 54.28 mL of toluene slurry of the solid support (X-1) prepared above (21 in terms of Al atoms). .12 mmol) was charged. Subsequently, 17.60 mL (0.047 mmol in terms of Zr atom) of a toluene solution of the transition metal complex represented by the compound (A-1) was added dropwise and reacted at room temperature for 1 hour to obtain an olefin polymerization catalyst (Y-6). )

<Ethylene polymer (γ-1)>
250 L of purified heptane was placed in a polymerization tank having an internal volume of 500 liters sufficiently purged with nitrogen, to which 89 mmol of triisobutylaluminum and 2.38 g of olefin polymerization catalyst (Y-6) were added in terms of solid components. Thereafter, polymerization was carried out under the same conditions as in Example 1. The polymer obtained at 80 ° C. (first stage) polymerization has a density of 969 (kg / m ³ ) and an intrinsic viscosity [η] of 0.92 (dl / g). The polymerization activity was 88.1 kg-PE / mmol-Zr · hr, and the productivity was 2760 g-PE / g-cat. · Hr.

Subsequently, 75 degreeC (2nd stage) superposition | polymerization was performed, polymerization activity was 66.5kg-PE / mmol-Zr * hr, and productivity was 2030g-PE / g-cat. * Hr. The intrinsic viscosity [η] of the polymer obtained after completion of the polymerization was 3.23 dL / g, the polymerization amount of the polymer was 22.4 kg, and the polymerization activity was 77.2 kg-PE / mmol-Zr · hr. Productivity was 2380 g-PE / g-cat. · Hr.
From the intrinsic viscosity [η] after completion of the first stage and the polymerization, the intrinsic viscosity [η] of the high molecular weight component of the ethylene copolymer polymerized in the second stage was 6.15 (dl / g).

[Reference Example 2]
[Synthesis Example 9]
[Preparation of solid catalyst component (Y-7) by supporting transition metal compound]
A 500 mL glass container equipped with a magnetic stirrer and fully purged with nitrogen was charged with 149.7 mL of dehydrated toluene, and 54.28 mL of toluene slurry of the solid support (X-1) prepared above (21 in terms of Al atoms). .12 mmol) was charged. Subsequently, 28.41 mL (0.026 mmol in terms of Zr atom) of a toluene solution of the transition metal complex represented by the compound (A-2) was added dropwise, and the mixture was reacted at room temperature for 1 hour, and the olefin polymerization catalyst (Y-7 )

<Ethylene polymer (γ-2)>
250 L of purified heptane was placed in a polymerization tank having an internal volume of 500 liters sufficiently purged with nitrogen, and 89 mmol of triisobutylaluminum and 2.38 g of olefin polymerization catalyst (Y-7) were added thereto in terms of solid components. Thereafter, polymerization was carried out under the same conditions as in Example 1. The polymer obtained at 80 ° C. (first stage) polymerization has a density of 953 (kg / m ³ ) and an intrinsic viscosity [η] of 2.30 (dl / g). The polymerization activity was 78.9 kg-PE / mmol-Zr · hr, and the productivity was 2470 g-PE / g-cat. · Hr.

  Subsequently, 75 degreeC (2nd stage) polymerization was performed, polymerization activity was 18.0kg-PE / mmol-Zr * hr, and productivity was 560g-PE / g-cat. * Hr. The intrinsic viscosity [η] of the polymer obtained after completion of the polymerization is 5.44 dL / g, the polymerization amount of the polymer is 14.0 kg, and the polymerization activity is 47.0 kg-PE / mmol-Zr · hr. Productivity was 1460 g-PE / g-cat. · Hr.

From the intrinsic viscosity [η] after completion of the first stage and the polymerization, the intrinsic viscosity [η] of the high molecular weight component of the ethylene copolymer polymerized in the second stage was 18.0 (dl / g).
From Reference Example 1 and Reference Example 2, the intrinsic viscosity [η] of the high molecular weight component of the ethylene copolymer polymerized with the transition metal compound (A-1) at 75 ° C. (second stage) in Example 1 is 6. 1 (dl / g), the polymerization amount is 27.5% by weight of the total amount, and the ethylene copolymer polymerized with the transition metal compound (A-2) at 75 ° C. (second stage) in Example 1 The intrinsic viscosity [η] of the high molecular weight component is 18.0 (dl / g), and the polymerization amount is 7.5% by weight of the total amount.

Claims (10)

An ethylene polymer (α) characterized by satisfying the following requirements [a], [b], [c], [d] and [e] simultaneously.
[a] Melt flow rate (HLMI) at a temperature of 190 ° C. and a load of 21.6 kg is in a range of 1.0 to 10 g / 10 minutes,
[b] a density in the range of 945 to 965 kg / m ³ ;
[c] length 5.0 mm, using a die having a diameter 0.5 mm, shear rate 19460s at 210 ° C. ^- pressure at ^{1 (σ,} Pa) in the range relation of the following and HLMI,
log (σ) ≧ −0.12 × log (HLMI) +7.65
[d] The relationship between Charpy impact strength (MPa) at −40 ° C. measured according to JIS K7111, and HLMI is in the following range:
log (Charchy impact strength) ≥ -1.1 x log (HLMI) + 2.16
[e] The swell ratio measured at 230 ° C. is in the range of 1.56 or more. The ethylene polymer (α) according to claim 1, further satisfying the following requirement [f].
[f] In an environmental stress crack resistance test (ESCR test; test temperature 65 ° C., test piece thickness 3 mmt) measured according to ASTM D1693, the 50% crack generation time (F ₅₀ ) is 300 hours or more. The ethylene polymer (α) according to claim 1 or 2, further satisfying the following requirement [g].
[g] In a tensile creep test (test temperature: 80 ° C.) measured in accordance with JIS K7115, when the test stress is 6 MPa, the creep strain after 100 hours is 15% or less. The ethylene polymer (α) according to any one of claims 1 to 3, further satisfying the following requirement [h].
[h] Mw / Mn and Mz _{+ 1} / Mw determined by gel permeation chromatography (GPC) measurement are in the following ranges.
4.0 ≦ (Mw / Mn) ≦ 22.0 and (Mz _{+ 1} / Mw) ≧ 16.0   The ethylene polymer (α) according to any one of claims 1 to 4, wherein the ethylene polymer (α) is for a hollow molded body.   The hollow molded object containing the layer which consists of an ethylene-type polymer ((alpha)) of any one of Claims 1-4.   A fuel tank, a kerosene can, a drum can, a chemical container, an agrochemical container, a solvent container, or a bottle comprising the hollow molded article according to claim 6.   5. A laminated structure comprising a layer (I) made of the ethylene polymer (α) according to claim 1, an adhesive layer (IV), a barrier layer (II), and a reproduction layer (III) is included. A fuel tank or a pesticide container characterized by comprising a hollow molded body.   The fuel tank or agricultural chemical container according to claim 8, wherein the layer (I) and the barrier layer (II) comprising the ethylene polymer (α) are laminated via the adhesive layer (IV). .   10. The fuel tank or agricultural chemical container according to claim 8, wherein the barrier layer (II) comprises an ethylene-vinyl alcohol copolymer.