JP6878942B2 - Polyethylene resin composition, its molded article and container - Google Patents

Description

The present invention relates to a polyethylene resin composition, and a molded product and a container made of the polyethylene resin composition.

In hollow molding, injection molding, inflation molding, and extrusion molding of polyethylene, a material having good molding processability and physical properties is generally required. In particular, polyethylene resins having excellent moldability, physical properties, and chemical properties are used for hollow bottles that are generally used as cosmetic containers, detergents, shampoo and rinse containers, and food containers such as cooking oil. Is widely used.
Furthermore, in recent years, in order to reduce costs, it has been required to reduce the weight and thickness of hollow bottles, and in these hollow bottle applications, particularly excellent characteristics such as environmental stress crack resistance and impact strength are required. There is. As the polyethylene satisfying such a requirement, a polyethylene having a relatively high molecular weight and a wide molecular weight distribution is suitable.

Polyethylene polymerized using a chromium-based catalyst has a relatively wide molecular weight distribution and has a long-chain branched structure, so that it is easy to hollow form, specifically, it has a large melt tension and swell ratio. In addition, since it is easy to uniformly thicken the pinch-off portion of the hollow bottle, it is generally widely used as a material for hollow molding.
Further, polyethylene two-stage polymerized using a titanium-based catalyst can be imparted with excellent environmental stress crack resistance by selectively copolymerizing a comonomer with a high molecular weight component, and has low molecular weight. Since it is possible to adjust the molecular weight and the molecular weight distribution by controlling the molecular weight component, it is generally widely used as a high environmental stress cracking grade suitable for hollow molding.
Then, a polyethylene polymer composition obtained by mixing polyethylene polymerized in two stages using a titanium-based catalyst and polyethylene polymerized using a chromium-based catalyst and taking advantage of each other's advantages is disclosed (for example, Patent Documents). See 1-7.).
However, as the weight of the container is reduced and the design is diversified more and more, if the rigidity of the container is to be ensured while the container is thinned, it becomes necessary to increase the density of polyethylene, that is, the amount of comonomer copolymerization is suppressed. There is a need for it, which contradicts the maintenance of environmental stress crack resistance. Therefore, there is still a demand for a material that has an excellent balance between rigidity and environmental stress crack resistance and can cope with thinning.

Therefore, a polyethylene resin composition composed of multiple components, which contains polyethylene using a metallocene-based catalyst and has an improved balance between rigidity and environmental stress crack resistance, is disclosed (see, for example, Patent Documents 8 to 13).
However, polyethylene using a metallocene-based catalyst has a relatively narrow molecular weight distribution and a uniform comonomer distribution. Therefore, although it is extremely excellent in environmental stress crack resistance, it is poor in hollow formability. Since it has features such as low melt tension and low swell ratio, it is only used for the purpose of storing a specific content liquid or as a container having a specific shape.
Further, as described in Patent Document 8, polyethylene using a metallocene-based catalyst has a low melting point and crystallization temperature for the same density, that is, it is easily melted and difficult to crystallize due to its rigidity, so that it is crystallized. The phenomenon that the speed becomes slow is recognized, and there is a need to further increase the crystallization speed for high-speed molding.

Then, polyethylene containing a metallocene-based catalyst is mixed, and polyethylene polymerized using a chromium-based catalyst is mixed, and by taking advantage of each other's advantages, the balance between rigidity and environmental stress crack resistance is excellent, and it is also suitable for hollow moldability. The polyethylene polymer composition of interest is disclosed (for example, Patent Documents 14 to 16).
However, in Patent Document 14, by mixing polyethylene using a high molecular weight metallocene catalyst and polyethylene polymerized using a chromium catalyst, mechanical strength and moldability, compatibility of each component are good, and low gel is obtained. Although a composition having both properties is disclosed, the composition has a very high viscosity and is not suitable for high-speed moldability, and its use is limited to a large hollow molded container or the like.
Further, Patent Documents 15 and 16 describe a composition having both mechanical strength and moldability by mixing a composition containing polyethylene using a high-molecular-weight metallocene-based catalyst and polyethylene polymerized using a chromium-based catalyst. Although the material is disclosed, the compatibility of each component of the composition has not been sufficiently studied, and the molecular weight of polyethylene using a high-molecular-weight metallocene-based catalyst is too high or contributes to compatibility. Since the amount of polyethylene polymerized using the chromium-based catalyst is small, sufficient compatibility cannot be obtained, and the appearance of the molded product is not always sufficient.

On the other hand, for the purpose of further enhancing the environmental stress crack resistance of polyethylene using a metallocene catalyst, increasing the molecular weight is extremely effective, but the compatibility with other polyethylenes deteriorates, so polyethylene using a metallocene catalyst is used. In a polyethylene resin composition containing, it is important to design a resin that has both compatibility and environmental stress crack resistance.
In view of these circumstances, it is possible to achieve a high-speed molding high cycle with a high crystallization rate while having the hollow moldability, high rigidity, impact resistance, etc. required for the conventional polyethylene resin composition for containers. Further, there is a demand for a polyethylene material having a particularly excellent appearance of a molded product.

Therefore, the applicant has found a polyethylene material or the like having a high crystallization rate that can achieve a higher high-speed molding and high cycle while having hollow moldability, high rigidity, impact resistance, etc., and filed an application first. (Patent Documents 17 to 19). In Patent Documents 17 to 19, a metallocene-based catalyst containing Ti, Zr or Hf is polymerized with respect to 60 to 90% by mass of a specific polyethylene, the HLMFR and the density are each specific values, and long-chain branching is performed. A polyethylene resin composition for a container, which contains 10 to 40% by mass of a specific ethylene-based polymer having a structure and satisfies a specific property, is disclosed.
Further, in Patent Document 20, the applicant has described a polyethylene resin composition containing a specific amount of a polyethylene resin satisfying a specific property and a specific ethylene / α-olefin copolymer in a specific amount, and a molded product made of the same. It is disclosed.
However, the required performance required for the product is increasing day by day, and further performance improvement is required in the above-mentioned problems of the prior art.

JP-A-59-196345 JP-A-59-196346 Japanese Unexamined Patent Publication No. 60-03657 Japanese Unexamined Patent Publication No. 2004-059650 Japanese Unexamined Patent Publication No. 2004-091739 Japanese Unexamined Patent Publication No. 2004-168817 Japanese Unexamined Patent Publication No. 2005-298811 Japanese Unexamined Patent Publication No. 08-283476 Japanese Unexamined Patent Publication No. 08-283477 Japanese Unexamined Patent Publication No. 2006-833370 Japanese Unexamined Patent Publication No. 11-106574 Japanese Unexamined Patent Publication No. 11-199719 JP-A-2009-7579 Japanese Unexamined Patent Publication No. 2003-213503 Japanese Unexamined Patent Publication No. 11-138618 Special Table 2009-506163 Japanese Unexamined Patent Publication No. 2013-204015 Japanese Unexamined Patent Publication No. 2014-208749 Japanese Unexamined Patent Publication No. 2014-208750 Japanese Unexamined Patent Publication No. 2014-208817

An object of the present invention is that, in view of the above-mentioned problems of the prior art, it is excellent in hollow moldability, environmental stress crack resistance, impact resistance, can be molded thinner and lighter, and has a high crystallization rate. Excellent high-speed moldability, high-cycle molding, high melt tension, excellent draw-down resistance, good pinch-off characteristics, hollow molding of complex shapes is possible, and compatibility of resin components It is an object of the present invention to provide a polyethylene resin composition which is expensive and particularly excellent in the appearance of a molded product, and a molded product made of the same.

As a result of intensive studies to solve the above problems, the present inventors have contained a specific polyethylene component (A), a specific polyethylene component (D), and a specific polyethylene component (E) in a specific amount. With a polyethylene resin composition that satisfies specific properties, it has excellent hollow moldability, environmental stress crack resistance, and impact resistance, can be molded thinner and lighter, has a high crystallization rate, and has high-speed moldability. Excellent, high-cycle molding is possible, high melt tension is excellent, draw-down resistance is excellent, pinch-off characteristics are good, hollow molding of complicated shapes is possible, and compatibility of resin components is high, so that the molded product We have found that a polyethylene resin composition having a particularly excellent appearance and a molded product made of the same can be obtained, and have completed the present invention.

That is, the polyethylene resin composition of the present invention contains the following polyethylene component (A) in an amount of 10% by mass or more and 40% by mass or less, the following polyethylene component (D) in an amount of 5% by mass or more and 50% by mass or less, and the following polyethylene component (E). It contains 40% by mass or more and 85% by mass or less, and satisfies the following characteristics (1) to (8).
Polyethylene component (A); Characteristic (a1): Melt flow rate (HLMFR) at a temperature of 190 ° C. and a load of 21.6 kg is 0.2 g / 10 minutes or more and 5 g / 10 minutes or less, and characteristic (a2): density 0.915 g / cm ³ or more and 0.945 g / cm ³ or less, characteristic (a3): the following polyethylene component (B) and the following polyethylene component (C), (B): (C) = 5: 95 ~ Polyethylene containing in a ratio of 95: 5 (% by mass).
Polyethylene component (B); Characteristic (b1): Melt flow rate (HLMFR) at a temperature of 190 ° C. and a load of 21.6 kg is 0.2 g / 10 minutes or more and 2 g / 10 minutes or less, and characteristic (b2): density 0.900 g / cm ³ or more 0.950 g / cm ³ polyethylene satisfy the following.
Polyethylene component (C); Characteristic (c1): Melt flow rate (HLMFR) at a temperature of 190 ° C. and a load of 21.6 kg is 0.4 g / 10 minutes or more and 10 g / 10 minutes or less, and characteristic (c2): density 0.900 g / cm ³ or more 0.970 g / cm ³ polyethylene satisfy the following.
Polyethylene component (D); Characteristics (d1): Melt flow rate (HLMFR) at a temperature of 190 ° C. and a load of 21.6 kg is 4 g / 10 minutes or more and 7 g / 10 minutes or less , and characteristics (d2): density is 0. 945 g / cm ³ or more 0.965 g / cm ³ or less, the characteristics (d3): temperature 170 ° C., elongation strain rate 0.1: elongation viscosity measured at (in 1 / sec) eta (t) (unit: Polyethylene in which the variation point of extensional viscosity due to strain hardening is observed in both logarithmic plots of Pa · sec) and extension time t (unit: sec).
Polyethylene component (E); Characteristic (e1): Melt flow rate (MFR) at a temperature of 190 ° C. and a load of 2.16 kg is 10 g / 10 minutes or more and 200 g / 10 minutes or less, and characteristic (e2): density is 0. 960 g / cm ³ or more 0.980 g / cm ³ polyethylene satisfy the following.
Characteristic (1): MFR is 0.1 g / 10 minutes or more and 1 g / 10 minutes or less.
Characteristic (2): HLMFR is 10 g / 10 minutes or more and 50 g / 10 minutes or less.
Characteristic (3): The melt flow rate ratio (HLMFR / MFR), which is the ratio of HLMFR to MFR, is 50 or more and 140 or less.
Characteristics (4): density of 0.940 g / cm ³ or more 0.965 g / cm ³ or less.
Characteristic (5): Both extension viscosity η (t) (unit: Pa · second) and extension time t (unit: second) measured at a temperature of 170 ° C. and an extension strain rate of 0.1 (unit: 1 / sec). In the log-log plot, the variation point of the extensional viscosity due to strain hardening is observed.
Property (6): The rupture time (FNCT) at 80 ° C. and 3.7 MPa according to the full notch creep test is 285 hours or more.
Characteristic (7): The tensile impact strength is 233 kJ / m ² or more.
Characteristic (8): The melting tension is 40 mN or more.

Further, according to the present invention, a molded product produced by using the polyethylene resin composition is provided.

Further, according to the present invention, a container made by using the polyethylene resin composition is provided.

The polyethylene resin composition of the present invention contains a specific polyethylene component (B), which is a high molecular weight component, and a specific polyethylene component (C), which has a lower molecular weight than the component (B), as a component (B) and a component. A polyethylene component (A) having a structure obtained by multi-stage polymerization of (C), preferably a polyethylene component (A) having a structure obtained by multi-stage polymerization of component (B) and component (C) in this order. Since the polyethylene resin composition contains a specific polyethylene component (D) and a specific polyethylene component (E) in specific amounts, for example, the high molecular weight component (B) has a high viscosity and a relatively large molecular weight distribution. Even if it is narrow, the component (C) existing in the central portion of the particles of the component (A) promotes the dispersion of the component (B) when melt-kneaded with the material to be modified, so that the compatibility between the two is promoted. It has the effect of being an excellent polyethylene resin composition.
Therefore, it contains a relatively small amount of high molecular weight components having a relatively narrow molecular weight distribution, and can be highly dispersed without increasing the viscosity after blending with the material to be modified, and has hollow formability and environmental stress crack resistance. It has excellent properties and impact resistance, can be molded thinner and lighter, has a high crystallization rate, is excellent in high-speed moldability, can be molded in a high cycle, has a high melt tension, and has drawdown resistance. It is excellent, has good pinch-off characteristics, can be hollow molded into a complicated shape, has high compatibility of resin components, and has an effect that it is possible to provide a polyethylene resin composition having a particularly excellent appearance of a molded product.
Further, according to the present invention, it is possible to provide a molded product and a container having excellent environmental stress crack resistance and impact resistance, excellent surface texture, and good appearance.

FIG. 1 is a plot diagram of a typical extensional viscosity, and is a diagram for explaining a case where an inflection point of the extensional viscosity is observed. FIG. 2 is a plot diagram of a typical extensional viscosity, and is a diagram for explaining a case where an inflection point of the extensional viscosity is not observed.

1. 1. Polyethylene resin composition The polyethylene resin composition of the present invention contains the following polyethylene component (A) in an amount of 10% by mass or more and 40% by mass or less, the following polyethylene component (D) in an amount of 5% by mass or more and 50% by mass or less, and the following polyethylene component (E). ) Is contained in an amount of 40% by mass or more and 85% by mass or less, and satisfies the following characteristics (1) to (8).
Polyethylene component (A); Characteristic (a1): Melt flow rate (HLMFR) at a temperature of 190 ° C. and a load of 21.6 kg is 0.2 g / 10 minutes or more and 5 g / 10 minutes or less, and characteristic (a2): density 0.915 g / cm ³ or more and 0.945 g / cm ³ or less, characteristic (a3): the following polyethylene component (B) and the following polyethylene component (C), (B): (C) = 5: 95 ~ Polyethylene containing in a ratio of 95: 5 (% by mass).
Polyethylene component (B); Characteristic (b1): Melt flow rate (HLMFR) at a temperature of 190 ° C. and a load of 21.6 kg is 0.2 g / 10 minutes or more and 2 g / 10 minutes or less, and characteristic (b2): density 0.900 g / cm ³ or more 0.950 g / cm ³ polyethylene satisfy the following.
Polyethylene component (C); Characteristic (c1): Melt flow rate (HLMFR) at a temperature of 190 ° C. and a load of 21.6 kg is 0.4 g / 10 minutes or more and 10 g / 10 minutes or less, and characteristic (c2): density 0.900 g / cm ³ or more 0.970 g / cm ³ polyethylene satisfy the following.
Polyethylene component (D); Characteristics (d1): Melt flow rate (HLMFR) at a temperature of 190 ° C. and a load of 21.6 kg is 4 g / 10 minutes or more and 7 g / 10 minutes or less , and characteristics (d2): density is 0. 945 g / cm ³ or more 0.965 g / cm ³ or less, the characteristics (d3): temperature 170 ° C., elongation strain rate 0.1: elongation viscosity measured at (in 1 / sec) eta (t) (unit: Polyethylene in which the variation point of extensional viscosity due to strain hardening is observed in both logarithmic plots of Pa · sec) and extension time t (unit: sec).
Polyethylene component (E); Characteristic (e1): Melt flow rate (MFR) at a temperature of 190 ° C. and a load of 2.16 kg is 10 g / 10 minutes or more and 200 g / 10 minutes or less, and characteristic (e2): density is 0. 960 g / cm ³ or more 0.980 g / cm ³ polyethylene satisfy the following.
Characteristic (1): MFR is 0.1 g / 10 minutes or more and 1 g / 10 minutes or less.
Characteristic (2): HLMFR is 10 g / 10 minutes or more and 50 g / 10 minutes or less.
Characteristic (3): The melt flow rate ratio (HLMFR / MFR), which is the ratio of HLMFR to MFR, is 50 or more and 140 or less.
Characteristics (4): density of 0.940 g / cm ³ or more 0.965 g / cm ³ or less.
Characteristic (5): Both extension viscosity η (t) (unit: Pa · second) and extension time t (unit: second) measured at a temperature of 170 ° C. and an extension strain rate of 0.1 (unit: 1 / sec). In the log-log plot, the variation point of the extensional viscosity due to strain hardening is observed.
Property (6): The rupture time (FNCT) at 80 ° C. and 3.7 MPa according to the full notch creep test is 285 hours or more.
Characteristic (7): The tensile impact strength is 233 kJ / m ² or more.
Characteristic (8): The melting tension is 40 mN or more.

<Polyethylene component (A)>
Characteristics (a1)
The polyethylene component (A) used in the present invention satisfies the following characteristics (a1) to (a3).
Characteristic (a1): Melt flow rate (HLMFR) at a temperature of 190 ° C. and a load of 21.6 kg is 0.2 g / 10 minutes or more and 5 g / 10 minutes or less.
Characteristic (a2): Density is 0.915 g / cm ³ or more and 0.945 g / cm ³ or less.
Property (a3): The following polyethylene component (B) and the following polyethylene component (C) are contained in a ratio of (B): (C) = 5:95 to 95: 5 (mass%).
Polyethylene component (B); Characteristic (b1): Melt flow rate (HLMFR) at a temperature of 190 ° C. and a load of 21.6 kg is 0.2 g / 10 minutes or more and 2 g / 10 minutes or less, and characteristic (b2): density 0.900 g / cm ³ or more 0.950 g / cm ³ polyethylene satisfy the following.
Polyethylene component (C); Characteristic (c1): Melt flow rate (HLMFR) at a temperature of 190 ° C. and a load of 21.6 kg is 0.4 g / 10 minutes or more and 10 g / 10 minutes or less, and characteristic (c2): density 0.900 g / cm ³ or more 0.970 g / cm ³ polyethylene satisfy the following.

Characteristics (a1)
The polyethylene component (A) used in the present invention has a melt flow rate (HLMFR) of 0.2 g / 10 minutes or more and 5 g / 10 minutes or less at a temperature of 190 ° C. and a load of 21.6 kg from the viewpoint of exerting the effect of the present invention. Select the one that is. The HLMFR of the polyethylene component (A) is preferably in the range of 0.3 g / 10 minutes or more, 1.0 g / 10 minutes or less, and more preferably 0.4 g / 10 minutes or more, 0.7 g / 10 minutes or less. When this HLMFR is 0.2 g / 10 minutes or more, the HLMFR can be achieved within the specified range in the final resin composition, the fluidity is improved, and the compatibility is improved, so that the appearance of the molded product is good. Can be. On the other hand, when the HLMFR is 5 g / 10 minutes or less, the environmental stress crack resistance can be achieved in the final resin composition, and the long-term durability of the molded product can be improved.
In this specification, the HLMFR of the polyethylene component and the polyethylene resin composition can be measured in accordance with JIS K6922-2: 1997.
The HLMFR of the polyethylene component (A) can be adjusted mainly by the amount of hydrogen at the time of polymerization of the polyethylene component (A) and the polymerization temperature.

Characteristic (a2)
As the polyethylene component (A) used in the present invention, one having a density of 0.915 g / cm ³ or more and 0.945 g / cm ³ or less is selected from the viewpoint of exerting the effect of the present invention. The density of polyethylene component (A) is preferably 0.920 g / cm ³ or more 0.935 g / cm ³ or less, still more preferably 0.922 g / cm ³ or more 0.930 g / cm ³ or less. When the density is 0.915 g / cm ³ or more, the density range in the final resin composition can be achieved and the desired rigidity can be obtained. On the other hand, when the density is 0.945 g / cm ³ or less, the desired environmental stress crack resistance is obtained in the final resin composition.
In this specification, the densities of the polyethylene component and the polyethylene resin composition can be measured according to JIS K6922-1, 2: 1997.
The density of the polyethylene component (A) can be adjusted mainly by the amount of α-olefin during the polymerization of the polyethylene component (A).

Characteristic (a3)
The polyethylene component (A) used in the present invention comprises the following polyethylene component (B) and the following polyethylene component (C) in a ratio of (B) :( C) = 5: 95 to 95: 5 (mass%). It is a multimodal polyethylene containing, and the ratio of the polyethylene component (B) is preferably 15 to 85% by mass, more preferably 35 to 75% by mass. Further, the polyethylene component (A) is preferably multi-stage polymerized, and more preferably the component (B) and the component (C) are multi-stage polymerized in this order.
Multimodal polyethylene refers to a polyethylene composition having two or more components. Each component is different in molecular weight, monomer composition, density, long-chain branch concentration, long-chain branch distribution or a combination thereof. Further, the multimodal polyethylene may be composed of a plurality of different molecular weight fractions, may be composed of fractions resulting in a plurality of different comonomer contents, or may be composed of a plurality of different polymerization conditions. It may contain the polyethylene fraction produced below. The prefix "mulch" of "multimodal" means that the number of polymer fractions constituting the polyethylene composition is plural. Thus, for example, a composition consisting of two fractions is called "bimodal" and a composition consisting of three fractions is called "trimodal".
Such a molecular weight distribution curve of multimodal polyethylene, that is, a graph of the polymer weight fraction as a function of the molecular weight, shows a shape having two or more maximum values or a shape that can be divided into a plurality of molecular weight distribution curves. Things can be mentioned.

<Polyethylene component (B)>
The polyethylene component (B) is polyethylene that satisfies the following characteristics (b1) to (b2).
Characteristic (b1): Melt flow rate (HLMFR) at a temperature of 190 ° C. and a load of 21.6 kg is 0.3 g / 10 minutes or more and 1 g / 10 minutes or less.
Characteristics (b2): density of 0.900 g / cm ³ or more 0.950 g / cm ³ or less.

Characteristic (b1)
The high load melt flow rate (HLMFR, temperature 190 ° C., load 21.60 kg) of the component (B) in the present invention needs to be 0.2 to 2 g / 10 minutes. It is preferably 0.3 to 0.9 g / 10 minutes, more preferably 0.3 to 0.8 g / 10 minutes. When the HLMFR is 0.2 g / 10 minutes or more, the desired mixing property can be obtained. On the other hand, when the HLMFR is 2 g / 10 minutes or less, the desired impact strength and the like can be obtained.
The HLMFR of the component (B) can be adjusted mainly by the amount of hydrogen at the time of manufacturing the component (B).

Characteristic (b2)
The density of the component (B) in the present invention must be 0.900~0.950g / cm ^3, preferably 0.910 to 0.935 g / cm ^3, more preferably 0.915 to 0 .935 g / cm ³ . When the density is 0.900 g / cm ³ or more, the desired rigidity can be obtained. On the other hand, when the density is 0.950 g / cm ³ or less, the desired impact strength and the like can be obtained.
The density of the component (B) can be adjusted mainly by the amount of α-olefin during the production of the component (B).

<Polyethylene component (C)>
The polyethylene component (C) is polyethylene satisfying the following characteristics (c1) to (c2).
Characteristic (c1): Melt flow rate (HLMFR) at a temperature of 190 ° C. and a load of 21.6 kg is 0.4 g / 10 minutes or more and 10 g / 10 minutes or less.
Characteristics (c2): density of 0.900 g / cm ³ or more 0.970 g / cm ³ or less.
The polyethylene component (C) is polyethylene having a lower molecular weight than the polyethylene component (B).

Characteristic (c1)
The high load melt flow rate (HLMFR, temperature 190 ° C., load 21.60 kg) of the component (C) in the present invention needs to be 0.4 to 10 g / 10 minutes. It is preferably 0.4 to 3 g / 10 minutes, more preferably 0.4 to 2 g / 10 minutes. When the HLMFR is 0.4 g / 10 minutes or more, the desired mixing property can be obtained. On the other hand, when the HLMFR is 10 g / 10 minutes or less, the desired dispersibility of the component (B) can be obtained.
The HLMFR of the component (C) can be adjusted mainly by the amount of hydrogen at the time of manufacturing the component (C).

Characteristic (c2)
The density of the component (C) in the present invention must be 0.900~0.970g / cm ^3, preferably 0.910~0.965g / cm ^3, more preferably 0.915 to 0 .965 g / cm ³ . When the density is 0.900 g / cm ³ or more, the desired rigidity can be obtained. On the other hand, when the density is 0.970 g / cm ³ or less, the desired impact strength and the like can be obtained.
The density of the component (C) can be adjusted mainly by the amount of α-olefin during the production of the component (C).

<Manufacturing method of polyethylene component (A)>
The polyethylene component (A) used in the present invention is preferably obtained by multi-stage polymerization of the component (B) and the component (C), and from the characteristics and working aspects of the obtained resin composition. Therefore, it is preferable that the component (B) and the component (C) are obtained by multi-stage polymerization in this order. The multistage polymerization is more preferably continuous multistage polymerization.
Generally, it is said that the dispersibility of a high molecular weight component is affected by the difference in viscosity of the components adjacent to the high molecular weight component at the time of mixing, and the smaller the difference in viscosity, the better the dispersibility of the high molecular weight component.
The polyethylene resin composition of the present invention is produced by a specific production method that satisfies the above specific physical properties, polymerizes the component (B) first, and then produces the specific component (C) by multistage polymerization. As a result, the previously produced high molecular weight component (B) present on the outer surface of the particles of the polyethylene component (A) is present in the central portion, and the later produced component (C) causes the polyethylene component before melt-kneading. It is presumed that the particles (A) are spread and diffused in the state of particles.
In the polyethylene component (A), the component (B) has a high probability of being present on the outer surface of the particles of the polyethylene component (A), and the component (C) has a high probability of being present in the center of the particles of the polyethylene component (A). Those having an existing structure are preferable. The content mass ratio of the component (B) and the component (C) in the polyethylene component (A) is as described above.
As a component adjacent to the high molecular weight component (B) during melt-kneading with the material to be modified, a material to be modified can be considered in addition to the component (C), but the component (B) with respect to the dispersibility of the component (B). ) And the effect of the viscosity difference between the material to be modified are considered to be smaller than the effect of the viscosity difference between the component (B) and the component (C). This is because the component (B) has a high affinity with the component (C) produced by continuous polymerization, so that the viscosity ratio with the component (C) is higher than the viscosity ratio with the material to be modified to be added later. It is thought that it is strongly influenced.
In this way, in the molded product of the composition using the polyethylene resin composition of the present invention, the component (B) which is a high molecular weight component is highly dispersed, the generation of high molecular weight gel is suppressed, and the appearance is impaired. It is considered that the mechanical strength such as impact strength and rigidity of the molded product can be highly improved.
Here, "highly dispersed" specifically means that the evaluation is 4 or less when the fish eye is measured by the measurement method (<mixability evaluation method>) described below. Say.
Therefore, the molded product of the composition using the polyethylene resin composition of the present invention suppresses the generation of high molecular weight gel and contains a relatively small amount of high molecular weight components having a relatively narrow molecular weight distribution in order to improve physical properties and the like. Although the viscosity of the polyethylene resin composition of the present invention as a whole is far from that of the high molecular weight component, when it is made into a molded product, unevenness due to the high molecular weight gel caused by poor dispersibility does not occur, and the appearance is obtained. It is estimated to be excellent.

<Mixability evaluation method>
The fish eye of the polyethylene resin composition of the present invention can be measured by the following method.
The sample to be measured was compressed by a mold having a thickness of 0.35 mm and two press molding machines for compression processing and cooling at a temperature of 180 ° C. and a pressure of 100 kgf / cm ² in the first step. In the second step, a press sheet having a thickness of 0.4 mm is formed by cooling at a temperature of 30 ° C. and a pressure of 50 kgf / cm ^2. This press sheet is cut into a 50 × 50 × 0.4 mm test piece.
Next, the test piece is stretched by a biaxial stretching device. As the biaxial stretching device, for example, a biaxial stretching device SS-60 manufactured by Shibayama Kagaku Kikai Seisakusho Co., Ltd. is used, and the test piece is stretched twice at a temperature of 150 ° C. and a stretching speed of 60 mm / min. In the stretching procedure, the 1 cm portion on each side of the test piece is chucked by the four chuck portions of the biaxial stretching device, and the unchucked central portion of the press sheet is set so as to form a 30 × 30 mm square. After that, this test piece was heated to a temperature of 130 to 170 ° C., biaxially stretched until the distance between the diagonal chucks became 60 mm, and the unchucked central portion was stretched about twice. create.
An image is taken using a reflective 3D microscope on the surface of a 30 × 30 mm square area located approximately in the center of the biaxially stretched sheet. The magnification of the 3D microscope is 10 times, and the range (one field of view) of the sheet to be photographed is 10 × 10 mm. In order to improve the reliability of the measurement, one sample is photographed four times in a square area of 30 × 30 mm located in the center of the sheet so that the respective imaging fields of view do not overlap. The captured image is binarized into a fisheye portion and a non-fisheye portion (uniform matrix portion). The condition of the binarization process can be appropriately searched and set by the measurer.
The binarized image is read by a scanner and digitized to obtain image data.
The resolution of the scanner is 600 dpi or higher, preferably 900 dpi or higher. As the scanner, for example, a scanner GT-F670 (manufactured by EPSON, resolution: 4800 dpi) can be used.
The analysis of image data is realized, for example, by a personal computer and a software program executed on the personal computer. By processing the image data with a personal computer, it is possible to calculate characteristic parameters such as the area of each particle, the perimeter, the major / minor diameter ratio, the particle size, and the circularity. For the calculation of the feature parameters in this case, commercially available image processing software or the like can be used. As commercially available image analysis software, for example, WinROOF manufactured by Mitani Corporation can be used.
The image data is processed by binarizing at a certain appropriate level by setting a threshold value for the color scheme of the black portion and the white portion of the image. The condition of the binarization process can be appropriately searched and set by the measurer.
In image analysis, the area, perimeter, maximum length, maximum length vertical length (length in the direction perpendicular to the maximum length), etc. of each particle are calculated by known means, and various parameters of the particle are calculated for each particle from them. Can be calculated. The calculated parameters are the equivalent circle diameter of the particle (the diameter of the circle with the area equal to the area of the image of the particle) and the circularity (the ratio of the circumference of the circle with the area equal to the area of the image of the particle to the circumference of the image). ), Aspect ratio (ratio of maximum length of particle image to maximum length vertical length), etc.
The equivalent circle diameter is the equivalent circle diameter = (area value of the particle image / π) ^1/2 × 2, and the circularity is the circularity = (perimeter of the circle having the area value of the image of the particle) / ( The perimeter of the particle image) and the aspect ratio are calculated by (maximum length of the particle image) / (maximum length of the particle image and vertical length).
In the present invention, as the measurement of the fish eye, the area ratio of the fish eye in the image is obtained. For the area ratio of the fish eye of one sample, the average value of the measured values obtained in each of the four fields of view taken on one test piece is calculated.
For example, when the area ratio of fish eyes in the image is 0.2% or less, it is "1", when it is more than 0.2 to 0.5%, it is "2", and when it is more than 0.5 to 3.0%. The case is "3", the case of more than 3.0 to 5.0% is "4", the case of more than 5.0 to 10.0% is "5", and the case of more than 10.0% is "6". , Can be evaluated.

According to the above measurement method, for example, it is possible to measure the fish eye more finely than in the case of evaluating by the gloss of the injection molded product, so that it can be used as an evaluation of high dispersibility.

The type of the polyethylene component of the component (B) and the component (C) is preferably an ethylene homopolymer and / or a copolymer of ethylene and α-olefin, that is, an ethylene-based polymer. However, in order to further improve the mechanical strength, it is more preferable that the component (B) and the component (C) are ethylene / α-olefin copolymers.
The component (B) and the component (C) are homopolymerized with ethylene or an α-olefin having 3 to 12 carbon atoms with ethylene, for example, propylene, 1-butene, 1-pentene, 1-hexene, 4-methyl-1-. It is obtained by copolymerization with penten, 1-octene and the like. In addition, copolymerization with a diene is also possible for the purpose of modification. Examples of the diene compound used at this time include butadiene, 1,4-hexadiene, ethylidene norbornene, dicyclopentadiene and the like.
The comonomer content in the polymerization of the component (B) and the component (C) can be arbitrarily selected. For example, in the case of copolymerization of ethylene and an α-olefin having 3 to 12 carbon atoms. The α-olefin content in the ethylene / α-olefin copolymer is 0 to 40 mol%, preferably 0 to 30 mol%.
The ethylene-based polymer used in the polyethylene resin composition of the present invention may be one using ordinary ethylene as a raw material, or one using ethylene obtained from plant-derived ethanol or the like as a raw material.

The polymerization catalyst of the polyethylene component of the component (B) and the component (C) is not particularly limited, but from the viewpoint of the balance between HLMFR and density within the scope of the present invention, a metallocene catalyst or a Ziegler-based catalyst is preferably used, and more preferably a metallocene. A catalyst is used.
As the Ziegler-based catalyst, a Ziegler-Natta catalyst as an olefin coordination polymerization catalyst composed of a combination of a transition metal compound and an alkyl compound of a typical metal, particularly a solid catalyst component in which a titanium compound is supported on a magnesium compound and an organic aluminum compound are used. Please refer to the combined so-called Mg-Ti Ziegler catalyst (for example, "Catalyst Utilization Dictionary; 2004 Industrial Research Council", "Application System Diagram-Transition of Olefin Polymerization Catalysts-; 1995 Invention Association" and the like. ) Is suitable because it is inexpensive, highly active, and has excellent suitability for the polymerization process.
Among them, an inert carrier substance-supporting Mg / Ti catalyst as described in JP-A-54-142192 and JP-A-54-148903, that is, for example, a tetrahydrofuran solution of _{anhydrous MgCl 2 and TiCl 3} or the homogeneous mixture of TiCl _4, in advance and impregnating the treated porous silica triethylaluminum catalyst and obtained solidified dry dry, as described in JP-a-63-117019, the organoaluminum A catalyst obtained by subjecting an Mg / Ti catalyst to olefin prepolymerization in the presence, for example, a solid component obtained by a reaction of _{MgCl 2} and Ti (OnBu) _{4 with methylhydrodienepolysiloxane, and TiCl 4} and methylhydrodi. Examples thereof include a prepolymerized catalyst obtained by prepolymerizing a catalyst obtained by introducing a mixed solution of empolysiloxane in the presence of triethylaluminum.
Further, a catalyst component containing a low valence titanium atom and organic aluminum obtained by reacting a magnesium-aluminum composite with a tetravalent titanium compound as described in Japanese Patent Application Laid-Open No. 60-195108. Olefin polymerization catalyst in combination with a compound, methylaluminum sesquichloride, etc. in a homogeneous mixture of magnesium ethoxydo, tri-n-butoxymonochlorotitanium, n-butanol as described in JP-A-56-61406, etc. Examples thereof include a solid catalyst obtained by dropping, a solid catalyst for olefin polymerization containing magnesium, halogen, titanium and an electron donor as described in JP-A-2001-139635.
In the present invention, an ethylene-based polymer having a narrow molecular weight distribution and a narrow copolymer composition distribution can be produced with high activity, and therefore is preferably selected from the magnesium compound group represented by the following general formula (a). An Mg—Ti Ziegler catalyst characterized by containing at least a compound selected from the group of titanium compounds represented by the following general formula (b) is used.

General formula (a): Mg, MgO, or MgX ¹ _m R ¹ _n (OR ² ) _2-mn
Here, X ¹ is a halogen atom, preferably a chlorine atom, and R ¹ is a hydrocarbon group having 1 to 10 carbon atoms, preferably a hydrocarbon group having 1 to 6 carbon atoms, and more preferably methyl, ethyl, propyl, and the like. It is butyl, and R ² is hydrogen or a hydrocarbon group having 1 to 10 carbon atoms, preferably a hydrocarbon group having 1 to 6 carbon atoms, and more preferably methyl, ethyl, propyl or butyl. m and n are numbers that satisfy 0 ≦ m ≦ 2, 0 ≦ n ≦ 2, and 0 ≦ m + n ≦ 2, respectively.

Examples of preferred embodiments of the general formula (a) are Mg, MgO, MgClR ¹ _n (OR ² ) _1-n , MgCl ₂ , MgX ¹ _m R ¹ _1-m (OR ² ), Mg (OR ² ) _2. However, 0 ≦ m ≦ 1 and 0 ≦ n ≦ 1, and examples of more preferable embodiments are Mg, MgO, MgClR ¹ , MgCl ₂ , MgX ¹ (OR ² ), and Mg (OR ² ) ₂ . An example of a particularly preferable embodiment is MgCl ₂ and Mg (OR ² ) ₂ . However, ^{the definitions of R 1} , R ² , and X ¹ are as described above.

Specifically, the magnesium compound contained in the general formula (a) can be listed below.
_{(1) Mg, MgO, MgF} 2, MgCl 2, MgBr 2, MgI 2, MgClF, MgBrCl, MgClI like,
(2) Mg (CH ₃ ) ₂ , Mg (C ₂ H ₅ ) ₂ , Mg (C ₃ H ₇ ) ₂ , Mg (C ₄ H ₉ ) ₂ , Mg (C ₆ H ₁₃ ) ₂ , Mg (C ₈₎ H ₁₇ ) ₂ , Mg (C ₁₀ H ₂₁ ) ₂ , Mg (C ₃ H ₅ ) ₂ , Mg (C ₆ H ₁₁ ) ₂ , Mg (C ₆ H ₅ ) ₂ , Mg (C ₆ H _4- CH ₃₎ ) ₂ , Mg (C ₆ H _4- C ₂ H ₅ ) ₂ , Mg (C ₆ H _4- C ₄ H ₉ ) ₂ , Mg (C ₆ H ₃ (CH ₃ ) ₂ ) ₂ , Mg (CH ₂ −) C ₆ H ₅ ) ₂ , Mg (C ₂ H _4- C ₆ H ₅ ) ₂ , Mg (CH ₃ ) (C ₂ H ₅ ), Mg (C ₂ H ₅ ) (C ₄ H ₉ ), Mg (CH) ₃ ) (C ₄ H ₉ ), Mg (C ₄ H ₉ ) (C ₆ H ₅ ), etc.
(3) Mg (OH) ₂ , Mg (OCH ₃ ) ₂ , Mg (OC ₂ H ₅ ) ₂ , Mg (OC ₃ H ₇ ) ₂ , Mg (OC ₄ H ₉ ) ₂ , Mg (OC ₆ H ₁₃ ) ₂ , Mg (OC ₆ H ₁₁ ) ₂ , Mg (OC ₆ H ₅ ) ₂ , Mg (OCH ₂ C ₆ H ₅ ) ₂ , Mg (OH) (OC ₂ H ₅ ), Mg (OC ₂ H ₅ ) ( OC ₄ H ₉ ), Mg (OC ₆ H ₄ CH ₃ ) ₂ etc.
Mg (C ₂ H ₅ ) Cl, Mg (C ₂ H ₅ ) Br, Mg (C ₂ H ₅ ) I, Mg (C ₄ H ₉ ) Cl, (4) Mg (C ₄ H ₉ ) Br, Mg ( C ₄ H ₉ ) I etc.
(5) Mg (OH) Cl, Mg (OH) Br, Mg (OH) I, Mg (OC ₂ H ₅ ) Cl, Mg (OC ₂ H ₅ ) Br, Mg (OC ₂ H5) I, Mg (OC) ₄ H ₉ ) Cl, Mg (OC ₄ H ₉ ) Br, Mg (OC ₄ H ₉ ) I, etc.
(6) Mg (C ₂ H ₅ ) (OC ₂ H ₅ ), Mg (C ₂ H ₅ ) (OC ₃ H ₇ ), Mg (C ₂ H ₅ ) (OC ₄ H ₉ ), Mg (C ₂ H) ₅ ) (OC ₆ H ₁₃ ), etc.

Among them, Mg, MgO, MgCl ₂ , MgBr ₂ , MgI ₂ , Mg (CH ₃ ) ₂ , Mg (C ₂ H ₅ ) ₂ , Mg (C ₃ H ₇ ) ₂ , Mg (C ₄ H _{9) are preferable.} ) ₂ , Mg (C ₂ H ₅ ) (C ₄ H ₉ ), Mg (OCH ₃ ) ₂ , Mg (OC ₂ H ₅ ) ₂ , Mg (OC ₃ H ₇ ) ₂ , Mg (OC ₄ H ₉ ) ₂ , Mg (OC ₆ H ₁₃ ) ₂ , Mg (C ₂ H ₅ ) Cl, Mg (C ₂ H ₅ ) Br, Mg (C ₂ H ₅ ) I, Mg (C ₄ H ₉ ) Cl, Mg (C ₄₎ H ₉ ) Br, Mg (C ₄ H ₉ ) I, Mg (OC ₂ H ₅ ) Cl, Mg (OC ₂ H ₅ ) Br, Mg (OC ₂ H ₅ ) I, more preferably MgO, MgCl. ₂ , Mg (C ₂ H ₅ ) ₂ , Mg (C ₄ H ₉ ) ₂ , Mg (C ₂ H ₅ ) (C ₄ H ₉ ), Mg (OCH ₃ ) ₂ , Mg (OC ₂ H ₅ ) ₂ , Mg (OC ₃ H ₇ ) ₂ , Mg (OC ₄ H ₉ ) ₂ , and particularly preferably _{Mg Cl 2} , Mg (C ₂ H ₅ ) ₂ , Mg (C ₄ H ₉ ) ₂ , Mg (C ₂ H). ₅ ) (C ₄ H ₉ ), Mg (OC ₂ H ₅ ) ₂ .

General formula (b): TiX ² _p (OR ³ ) _4-p
Here, X ² is a halogen atom, preferably a chlorine atom, and R ³ is a hydrocarbon group having 1 to 10 carbon atoms, preferably a hydrocarbon group having 1 to 6 carbon atoms, and more preferably methyl, ethyl, propyl, and the like. It is butyl, and p is a number satisfying 0 ≦ p ≦ 4.
An example of a preferred embodiment of the above general formula (b) is TiCl (OR ³ ) ₃ , TiCl ₂ (OR ³ ) ₂ , TiCl ₃ (OR ³ ), and TiCl ₄ , and an example of a more preferable embodiment is TiCl (OR). ³ ) ₃ , TiCl ₄ .
However, the definition of R ³ are as described above. Further, when p = 0, that is, when Ti (OR ³ ) ₄ is used, a halogenating agent is used in combination.
Here, the halogenating agent is not particularly limited as long as it is a compound having an action of substituting one or more hydrocarbon oxy groups (OR ^{3 ) of Ti (OR 3} ) _{4 with halogen, but for example, the present invention.} Among the magnesium compounds, aluminum compounds, and silicon compounds described in the above, compounds containing halogen atoms, halogens in the elemental state, hydrogen halides such as hydrogen chloride, haloalkanes such as chloroform, thionyl chloride, phosphorus oxychloride, Oxyhalides such as acyl chloride, non-metallic halides such as phosphorus trichloride, phosphorus pentachloride, ammonium chloride, boron chloride, sodium chloride, calcium chloride, zirconium chloride, vanadium chloride, chromium chloride, manganese chloride, iron chloride, chloride Metal halides such as nickel, tin chloride and zinc chloride are used.

Specifically, the titanium compound contained in the general formula (b) can be listed below.
(1) TiF ₄ , TiCl ₄ , TiBr ₄ , TiI ₄ , TiFCl ₃ , TiBrCl ₃ , TiBr ₂ Cl ₂ , TiBr ₃ Cl, TiBrCl ₂ I, etc.
(2) Ti (OCH ₃ ) ₄ , Ti (OC ₂ H ₅ ) ₄ , Ti (OC ₃ H ₇ ) ₄ , Ti (OC ₄ H ₉ ) ₄ , Ti (OC ₆ H ₁₃ ) ₄ , Ti (OC ₆₎ H ₁₁ ) ₄ , Ti (OC ₆ H ₅ ) ₄ , Ti (OC ₈ H ₁₇ ) ₄ , Ti (OC ₁₀ H ₂₁ ) ₄ , Ti (OCH ₂ C ₆ H ₅ ) ₄ , Ti (OCH ₂ C ₃ H) ₅ ) ₄ , Ti (OCH ₂ C ₆ H ₁₁ ) ₄ , Ti (OC ₃ H ₅ ) ₄ , Ti (OC ₂ H ₅ ) (OC ₄ H ₉ ) ₃ , Ti (OC ₂ H ₅ ) ₂ (OC ₄₎ H ₉ ) ₂ , Ti (OC ₂ H ₅ ) ₃ (OC ₄ H ₉ ), Ti (OC ₆ H ₄ CH ₃ ) ₄ , Ti (OC ₂ H ₅ ) (OC ₄ H ₉ ) (OC ₆ H ₁₃ ) _2nd prize,
(3) Ti (OCH ₃ ) Cl ₃ , Ti (OCH ₃ ) ₂ Cl ₂ , Ti (OCH ₃ ) ₃ Cl, Ti (OC ₂ H ₅ ) Cl ₃ , Ti (OC ₂ H ₅ ) ₂ Cl ₂ , Ti (OC ₂ H ₅ ) ₃ Cl, Ti (OC ₂ H ₅ ) (OC ₄ H ₉ ) Cl ₂ , Ti (OC ₂ H ₅ ) Br ₃ , Ti (OC ₂ H ₅ ) I ₃ , Ti (OC ₂ H) _{5) Cl 2 Br, Ti (} OC 2 H 5) Cl 2 I, Ti (OC 2 H 5) ClBrI, Ti (OC 3 H 7) Cl 3, Ti (OC 3 H 7) 2 Cl 2, Ti (OC ₃ H ₇ ) ₃ Cl, Ti (OC ₄ H ₉ ) Cl ₃ , Ti (OC ₄ H ₉ ) ₂ Cl ₂ , Ti (OC ₄ H ₉ ) ₃ Cl, Ti (OC ₄ H ₉ ) Br ₃ , Ti ( OC ₄ H ₉ ) I ₃ , Ti (OC ₅ H ₁₁ ) ₃ Cl, Ti (OC ₆ H ₁₃ ) ₃ Cl, Ti (OC ₆ H ₅ ) ₃ Cl, Ti (OC ₆ H ₅ ) ₂ Cl ₂ , Ti (OC ₆ H ₅ ) Cl _3, etc.

Among them, TiCl ₄ , Ti (OCH ₃ ) ₄ , Ti (OC ₂ H ₅ ) ₄ , Ti (OC ₃ H ₇ ) ₄ , Ti (OC ₄ H ₉ ) ₄ , Ti (OC ₆ H ₁₃ ) are preferable. ₄ , Ti (OC ₆ H ₁₁ ) ₄ , Ti (OC ₆ H ₅ ) ₄ , Ti (OCH ₃ ) Cl ₃ , Ti (OCH ₃ ) ₂ Cl ₂ , Ti (OCH ₃ ) ₃ Cl, Ti (OC ₂ H) ₅ ) Cl ₃ , Ti (OC ₂ H ₅ ) ₂ Cl ₂ , Ti (OC ₂ H ₅ ) ₃ Cl, Ti (OC ₃ H ₇ ) Cl ₃ , Ti (OC ₃ H ₇ ) ₂ Cl ₂ , Ti (OC) ₃ H ₇ ) ₃ Cl, Ti (OC ₄ H ₉ ) Cl ₃ , Ti (OC ₄ H ₉ ) ₂ Cl ₂ , Ti (OC ₄ H ₉ ) ₃ Cl, Ti (OC ₅ H ₁₁ ) ₃ Cl, Ti ( OC ₆ H ₁₃ ) ₃ Cl, Ti (OC ₆ H ₅ ) ₃ Cl, Ti (OC ₆ H ₅ ) ₂ Cl ₂ , Ti (OC ₆ H ₅ ) Cl ₃ , more preferably TiCl ₄ , Ti ( OC ₂ H ₅ ) ₄ , Ti (OC ₃ H ₇ ) ₄ , Ti (OC ₄ H ₉ ) ₄ , Ti (OC ₂ H ₅ ) Cl ₃ , Ti (OC ₂ H ₅ ) ₂ Cl ₂ , Ti (OC ₂₎ H ₅ ) ₃ Cl, Ti (OC ₃ H ₇ ) Cl ₃ , Ti (OC ₃ H ₇ ) ₂ Cl ₂ , Ti (OC ₃ H ₇ ) ₃ Cl, Ti (OC ₄ H ₉ ) Cl ₃ , Ti (OC) ₄ H ₉ ) ₂ Cl ₂ , Ti (OC ₄ H ₉ ) ₃ Cl, and particularly preferably TiCl ₄ , Ti (OC ₂ H ₅ ) ₄ , Ti (OC ₃ H ₇ ) ₄ , Ti (OC ₄ H). ₉ ) ₄ , Ti (OC ₂ H ₅ ) ₃ Cl, Ti (OC ₃ H ₇ ) ₃ Cl, Ti (OC ₄ H ₉ ) ₃ Cl.

As the metallocene catalyst, as an example of a polymerization catalyst suitable for multi-stage polymerization of the component (B) and the component (C), a metallocene catalyst (for example, "metallocene catalyst") which is an olefin polymerization catalyst composed of a metallocene-based transition metal compound and a co-catalyst component. Next-generation polymer industrialization technology (first and second volumes); published by Interresearch, Inc. in 1994) is relatively inexpensive, highly active, excellent in polymerization process suitability, and has a narrow molecular weight distribution and copolymerization composition distribution. It is used because an ethylene-based polymer can be obtained.
Among them, a catalyst system for olefin polymerization containing a so-called metallocene complex and an almoxane as described in JP-A-60-35007, etc., JP-A-8-34809, and JP-A-8-127613. A catalyst system using a co-catalyst component other than almoxene as described in Japanese Patent Application Laid-Open No. 11-193306, Japanese Patent Application Laid-Open No. 2002-515522, etc. is preferably used. As the metallocene complex, those having Ti, Zr, and Hf whose central metal is Group 4 of the periodic table show high activity against ethylene polymerization and are therefore preferably used. Various structures are currently known as the structures of the ligands of these central metals, and the polymerization performance such as the molecular weight of the produced polyethylene and the α-olefin copolymerizability has been investigated.
As described above, the polyethylene component (B) used in the present invention preferably has no long-chain branched structure or contains only a small amount. However, in the production of an ethylene-based polymer having such characteristics, a five-membered conjugate is used. The ring-structured ligand is preferably a so-called non-crosslinked complex in which the ring-structured ligand is not crosslinked with another ligand by a bridging group. , [2], [3] or [4] according to the structural classification of the metallocene compound, the compound [1] and the compound [3] are preferable, and the compound [1] is more preferable. However, it is said that the higher the concentration of ethylene or α-olefin in the polymerization field and the shorter the polymerization reaction time, the more disadvantageous it is for the formation of a long-chain branched structure. Needless to say, they are limited to relative ones assuming that they are carried out under the same conditions. Further, metallocene complexes described in JP-A-5-132518, JP-A-2000-154196, JP-A-2004-161760 and the like are also preferably used, and for example, JP-A-2002-535339 is described. A metallocene complex having a monocyclic or polycyclic heteroaromatic group containing the heteroatom of the above as a substituent on the conjugated five-membered ring structure ligand is also preferably used.

[Here, A ^{1 to} A ⁴ are ligands having a conjugated five-membered ring structure (A ^{1 to} A ⁴ may be the same or different ^{in the same compound), and Q 1} is two conjugated five-membered members. A binding group that bridges the ring ligand at an arbitrary position, Z ¹ and Z ² are M-bonded nitrogen atom, oxygen atom, silicon atom, phosphorus atom or sulfur atom-containing ligand, hydrogen atom. , a halogen atom or a hydrocarbon group, a bonding group Q ² is bridging the arbitrary position and Z ² conjugated five-membered ring ligand, the metal atom M is selected from group 4 of the periodic table and, X And Y indicate a hydrogen atom, a halogen atom, a hydrocarbon group, an alkoxy group, an amino group, a phosphorus-containing hydrocarbon group or a silicon-containing hydrocarbon group bonded to M, respectively. The above detailed definition shall be in accordance with the publication. ]

In the present invention, as an example of a suitable metallocene complex, the above-mentioned A1 to ^{A1 to the above-mentioned A1 to the above-mentioned A 1} to can be produced because it is possible to produce an ethylene-based polymer having a high molecular weight and a narrow molecular weight distribution and a narrow copolymer composition distribution with high polymerization activity. At least one or more, halogen, hydrocarbon group having 1 to 20 carbon atoms of the five H atoms on the ligand i.e. a cyclopentadienyl ring ligands having a conjugated five-membered ring structure represented as a ^4, Silicon-containing hydrocarbon group having 1 to 18 carbon atoms including silicon number 1 to 6, halogenated hydrocarbon group having 1 to 20 carbon atoms or hydrocarbon group substituted silyl group having 1 to 20 carbon atoms, carbon number 1 containing oxygen ~ 20 hydrocarbon groups (including alkoxy groups that are directly bonded to the ring with an oxygen atom; hereinafter, sulfur, nitrogen, and phosphorus are also the same), hydrocarbon groups having 1 to 20 carbon atoms containing sulfur, and carbon containing nitrogen. Examples thereof include a metallocene complex characterized in that it is substituted with a substituent selected from a hydrocarbon group having a number of 1 to 20 and a hydrocarbon group having a carbon number of 1 to 20 containing phosphorus. The substituents on the cyclopentadienyl ring may form a ring together with the carbon atom of the cyclopentadienyl ring to which the cyclopentadienyl ring is bonded. In this case, A ^{1 to} A ⁴ are an indenyl ring, an azulenyl ring, and the like. It can be a ligand having an accessory ring represented by a benzoindenyl ring, a fluorenyl ring, or the like, and is more preferable in that a higher molecular weight ethylene-based polymer can be obtained.

As a production process, the component (B) and the component (C) can be produced by a production process such as a vapor phase polymerization method, a solution polymerization method, or a slurry polymerization method, and are compared like the polyethylene resin composition of the present invention. The vapor phase polymerization method or the slurry polymerization method is desirable in that the viscosity of the reaction system does not increase even if polyethylene having a low target HLMFR, that is, a high molecular weight polyethylene is produced, and therefore the productivity is excellent. Among the polymerization conditions of the ethylene polymer, the polymerization temperature can be selected from the range of 0 to 300 ° C. In the case of vapor phase polymerization, the polymerization is carried out at a temperature lower than the melting point of the produced polymer. The polymerization pressure can be selected from the range of atmospheric pressure to about 4 MPa. It can be produced by performing gas phase polymerization of ethylene and α-olefin in the absence of a solvent in a state where oxygen, water and the like are substantially cut off. Inactive hydrogen having a relatively low boiling point such as propane, butane, pentane, and hexane may coexist to the extent that the flow of the polymer powder in the reactor is not hindered.

In the slurry polymerization, hydrogen supplied to the polymer is consumed as a chain transfer agent to determine the average molecular weight of the ethylene-based polymer produced, and a part of the hydrogen is dissolved in a solvent and discharged from the polymer. The solubility of hydrogen in the solvent is low, and the hydrogen concentration near the polymerization active site of the catalyst is low unless a large amount of gas phase parts are present in the polymerizer. Therefore, if the hydrogen supply amount is changed, the hydrogen concentration at the polymerization active point of the catalyst changes rapidly, and the molecular weight of the produced ethylene-based polymer changes following the hydrogen supply amount in a short period of time. Therefore, if the hydrogen supply amount is changed in a short cycle, a more homogeneous product can be produced. For this reason, it is preferable to adopt the slurry polymerization method as the polymerization method. Further, it is preferable to change the hydrogen supply amount discontinuously rather than continuously because the effect of widening the molecular weight distribution can be obtained.
In the component (B) and the component (C) used in the present invention, it is important to change the hydrogen supply amount as described above, but other polymerization conditions such as polymerization temperature, catalyst supply amount, ethylene and the like are used. It is also important to appropriately change the supply amount of olefin, the supply amount of comonomer such as 1-hexene, the supply amount of the solvent, etc. at the same time as or separately from the change of hydrogen.

In a preferred method for producing the polyethylene resin composition of the present invention, it is preferable that the step of polymerizing the component (B) and the step of polymerizing the component (C) satisfy the following conditions (J) and (K).
Condition (J): In the step of polymerizing the component (B), the molar ratio of hydrogen to ethylene in the gas phase portion in the polymerization reactor (H ₂ / C _{2 [gas phase portion B]} ) is 0.00 to 0. It is .40.
Condition (K): The average molar ratio of hydrogen and ethylene in the gas phase portion in the polymerization reactor in the step of polymerizing the component (B) (H ₂ / C _{2 [gas phase portion B average]} ) and the component (C). Ratio of the average molar ratio of hydrogen and ethylene in the gas phase part (H ₂ / C _{2 [gas phase part C average]} ) in the polymerization reactor in the step of polymerizing ([H ₂ / C _{2 [gas phase part C average]) ]} ] / [H ₂ / C _{2 [gas phase part B average]} ]) is 0.99 to 10.0.
[H ₂ / C _{2 [gas phase C average]} ] / [H ₂ / C _{2 [gas phase B average]} ] is more preferably 1.10 to 7.0, still more preferably 1.10 to 6. It is 0.0. At this time, H ₂ / C _{2 [gas phase average]} refers to the average value of the measured values 10 minutes after the initial stage and the final stage of each polymerization step. The difference in molecular weight between the component (B) and the component (C) when [H ₂ / C _{2 [gas phase C average]} ] / [H ₂ / C _{2 [gas phase B average]] is 0.90 or more.} Is not too small, and the effect of improving compatibility with the material to be modified is likely to be exhibited, which is preferable. Further, since [H ₂ / C _{2 [gas phase part C average]} ] / [H ₂ / C _{2 [gas phase part B average]} ] is 10.0 or less, the components (B) and the component (C) This is preferable because the difference in molecular weight does not become too large, the dispersion of the component (B) does not become insufficient, and the effect of improving compatibility with the material to be modified is easily exhibited. In the case of slurry polymerization using a loop type reactor filled with a polymerization liquid, which will be described later, there may be no gas phase part in the polymerization reactor, but usually a method of measuring the gas composition obtained by vaporizing the reaction solution is adopted. Therefore, it goes without saying that the definition _{of H 2} / C _{2 [gas phase portion]} in the present invention can be applied as it is.

As a method for producing the polyethylene resin composition of the present invention, a case where the step of polymerizing the component (B) and the step of polymerizing the component (C) satisfy the following conditions (L) and (M) is preferable. It can also be mentioned.
Condition (L): Ethylene homopolymerization or copolymerization of ethylene and α-olefin is carried out using a catalyst for olefin polymerization containing the following components (a), (b) and (c).
Component (a): At least one or more of the five H atoms on the cyclopentadienyl ligand contains halogen, a hydrocarbon group having 1 to 20 carbon atoms, and 1 to 18 carbon atoms containing 1 to 6 carbon atoms. Silicon-containing hydrocarbon groups, halogenated hydrocarbon groups with 1 to 20 carbon atoms or hydrocarbon group-substituted silyl groups with 1 to 20 carbon atoms, hydrocarbon groups with 1 to 20 carbon atoms containing oxygen (directly with oxygen atoms) It also contains an alkoxy group bonded to a ring, etc., hereinafter the same applies to sulfur, nitrogen, and phosphorus), a hydrocarbon group having 1 to 20 carbon atoms containing sulfur, a hydrocarbon group having 1 to 20 carbon atoms containing nitrogen, and phosphorus. Ti, Zr or Hf metallocene compound having a structure substituted with a group selected from hydrocarbon groups having 1 to 20 carbon atoms Component (b): Reacts with the metallocene compound of component (a) to form a cationic metallocene compound. Compound to be produced Component (c): Fine particle carrier Condition (M): Mass ratio of the ethylene-based polymer to be produced to the olefin polymerization catalyst used in the above condition (L) (ethylene-based polymer mass (g)) / The mass (g) of the olefin polymerization catalyst is 3000 to 50000.

Here, the component (a) refers to the above-mentioned metallocene compound, and more preferably on a ligand having a conjugated five-membered ring structure represented by ^{the above-mentioned A 1 to} A ^{4, that is, a cyclopentadienyl ring ligand.} Of the five H atoms, at least two or more, more preferably three or more, particularly preferably four or more, are halogens, hydrocarbon groups having 1 to 20 carbon atoms, and carbon atoms containing 1 to 6 silicon atoms. 1 to 18 silicon-containing hydrocarbon groups, 1 to 20 carbon halide hydrocarbon groups or 1 to 20 carbon hydrocarbon group-substituted silyl groups, oxygen-containing 1 to 20 carbon hydrocarbon groups (oxygen atoms) Also includes an alkoxy group directly bonded to the ring; hereinafter, the same applies to sulfur, nitrogen and phosphorus), a hydrocarbon group having 1 to 20 carbon atoms containing sulfur, a hydrocarbon group having 1 to 20 carbon atoms containing nitrogen, and the like. Substituents selected from phosphorus-containing hydrocarbon groups having 1 to 20 carbon atoms, more preferably hydrocarbon groups having 1 to 20 carbon atoms, silicon-containing hydrocarbons having 1 to 6 carbon atoms and having 1 to 18 carbon atoms. Group, hydrocarbon group having 1 to 20 carbon atoms or hydrocarbon group substituted silyl group having 1 to 20 carbon atoms, hydrocarbon group having 1 to 20 carbon atoms including oxygen, hydrocarbon having 1 to 20 carbon atoms including sulfur Hydrogen groups, more preferably hydrocarbon groups having 1 to 20 carbon atoms, silicon-containing hydrocarbon groups containing 1 to 6 silicon atoms and 1 to 18 carbon atoms, and oxygen-containing hydrocarbon groups having 1 to 20 carbon atoms, particularly Preferably, it is substituted with a hydrocarbon group having 1 to 20 carbon atoms, a silicon-containing hydrocarbon group having 1 to 18 carbon atoms containing 1 to 6 silicon atoms, and a hydrocarbon group having 1 to 20 carbon atoms including oxygen. Point to.

The substituents on the cyclopentadienyl ring may form a ring together with the carbon atom of the cyclopentadienyl ring to which the cyclopentadienyl ring is bonded. In this case, A ^{1 to} A ⁴ are an indenyl ring, an azulenyl ring, and the like. It can be a ligand having an accessory ring represented by a benzoindenyl ring, a fluorenyl ring, or the like, and is more preferable in that a higher molecular weight ethylene-based polymer can be obtained, and an indenyl ring is further preferable. When the ring is an indenyl ring, the compound represented by the above general formula [2], that is, a crosslinked bisindenyl complex structure is preferable, and the two indenyl rings are known carbon cross-linking groups or Si cross-linking groups at the 1-position position. A bridged structure is more preferable, and in addition, the above-mentioned halogen, a hydrocarbon group having 1 to 20 carbon atoms, and a silicon-containing hydrocarbon group having 1 to 18 carbon atoms including 1 to 6 silicon atoms, are located at the 2-position. A halogenated hydrocarbon group having 1 to 20 carbon atoms, a hydrocarbon group substituted silyl group having 1 to 20 carbon atoms, a hydrocarbon group having 1 to 20 carbon atoms containing oxygen (an alkoxy group directly bonded to the ring with an oxygen atom, etc.) (Hereinafter, the same applies to sulfur, nitrogen, and phosphorus), hydrocarbon groups having 1 to 20 carbon atoms containing sulfur, hydrocarbon groups having 1 to 20 carbon atoms containing nitrogen, and hydrocarbon groups having 1 to 20 carbon atoms containing phosphorus. A compound having a substituent selected from a hydrogen group is more preferable, and in addition, the above-mentioned halogen, a hydrocarbon group having 1 to 20 carbon atoms, and 1 to 18 carbon atoms including silicon numbers 1 to 6 are contained at the 4-position position. Silicon-containing hydrocarbon groups, halogenated hydrocarbon groups with 1 to 20 carbon atoms or hydrocarbon group-substituted silyl groups with 1 to 20 carbon atoms, hydrocarbon groups with 1 to 20 carbon atoms containing oxygen (the ring directly with an oxygen atom) Also includes an alkoxy group bonded to, etc. Hereinafter, the same applies to sulfur, nitrogen, and phosphorus), a hydrocarbon group having 1 to 20 carbon atoms containing sulfur, a hydrocarbon group having 1 to 20 carbon atoms containing nitrogen, and a carbon containing phosphorus. A compound having a substituent selected from the hydrocarbon groups of Nos. 1 to 20 is particularly preferable, and the substituents at the 2- and 4-positions are hydrocarbon groups having 1 to 20 carbon atoms and carbons containing 1 to 6 silicon atoms. Most preferably, a compound having a substituent selected from a silicon-containing hydrocarbon group having a number of 1 to 18 and a hydrocarbon group having a carbon number of 1 to 20 containing oxygen is preferable.

Regarding the component (b) and the component (c), a known technique is used, including the method described in JP-A-2011-137146 (paragraphs [0044] to [0069]), together with the method for producing a catalyst for olefin polymerization. Is applicable.

As a suitable production method for the polyethylene resin composition of the present invention to exhibit its modifying performance, it is desired that the amount of ethylene-based polymer produced per catalyst for olefin polymerization is sufficiently high. A more preferable range of the mass ratio (mass of ethylene-based polymer (g) / mass of catalyst for olefin polymerization (g)) is 5,000 to 30,000, and a more preferable range is 7,000 to 25,000. If the mass ratio is lower than 3000, the catalyst itself causes poor appearance and hinders the mixing of the component (B), which is not preferable. Further, if the mass ratio is higher than 50,000, it becomes difficult to control the production ratio of the component (B) and the component (C), or the mixture of the component (B) and the component (C) is biased, which is not preferable. ..

The component (B) and the component (C) can be composed of a plurality of components. The component (B) and the component (C) may be a polymer continuously polymerized in a multi-stage polymerization reactor using one type of catalyst, or may be produced in a multi-stage polymerization reactor using a plurality of types of catalysts. It may be a polymer.

It is preferable to use a so-called multi-stage polymerization method in which the component (B) and the component (C) are continuously polymerized by a plurality of reactors connected in series, and the component (B) and the component (C) are continuous as long as the specific one of the present invention can be obtained. Although it does not have to be continuous, continuous multistage polymerization is preferable because of the stability of the catalyst used and the sustainability of the activity. Then, after the step of polymerizing the component (B), the reaction system containing the component (B) is directly transferred to the reaction conditions of the component (C), and the step of polymerizing the component (C) is performed. , It is more preferable in terms of preventing catalyst poisoning and preventing diffusion of solvents and raw materials.
Further, the component (B) and / or the component (C) is a polyethylene resin containing a component (B) having a higher molecular weight so that the polyethylene resin composition of the present invention exhibits more excellent resin modification performance. The polyethylene resin composition of the present invention contains a polyethylene having a lower molecular weight component (C) for the purpose of designing as, or in order to increase the melt fluidity while maintaining the better resin modification performance. For the purpose of designing as a resin, each can be obtained by multi-stage polymerization of two or more stages.
A specific preferable polymerization method is the following method. That is, using a metallocene catalyst and two reactors, ethylene and α-olefin are introduced into the first-stage reactor to produce a polymer of low-density high-molecular-weight components, and the first-stage reaction is performed. This is a method in which the polymer extracted from the vessel is transferred to a second-stage reactor, ethylene and hydrogen are introduced into the second-stage reactor, and a polymer having a high-density low molecular weight component is produced. ..
In the case of multi-stage polymerization, the amount of ethylene-based polymer produced in the second and subsequent stages of polymerization and its properties are determined by determining the amount of polymer produced in each stage (which can be grasped by unreacted gas analysis, etc.). The physical properties of the polymer extracted after each stage can be measured, and the physical properties of the polymer produced in each stage can be determined based on the additivity.

<Modifier for resin>
The polyethylene component (A) used in the present invention is an ethylene-based polymer having excellent compatibility with the material to be modified, and the high molecular weight component is highly dispersed to improve the physical characteristics of the molded product without impairing the appearance. It can be suitably used as a modifier for resin. As a resin modifier, the polyethylene component (A) has mechanical strength such as flowability, extrusion property, wall thickness uniformity during blow molding, drawdown property, moldability, impact strength of molded product, rigidity, etc. And can be used for the purpose of expressing the smoothness of appearance.
When used as a resin modifier, antioxidants, UV absorbers, light stabilizers, lubricants, antistatic agents, antifogging agents, blocking inhibitors, processing aids, coloring contents, cross-linking agents, foaming agents, etc. Ingredients such as ordinary additives such as inorganic or organic fillers, flame retardants, etc. can be added.
The resin modifier of the present invention can be applied to various resins such as other olefin polymers and rubbers, but it is particularly preferable to apply it to an ethylene-based polymer, which will be described below in the present invention. It is necessary to apply to the specific polyethylene components (D) and (E) to form the polyethylene resin composition of the present invention.

<Polyethylene component (D)>
The polyethylene component (D) used in the polyethylene resin composition of the present invention is polyethylene satisfying the following properties (d1) to (d3).
Characteristics (d1): Melt flow rate (HLMFR) at a temperature of 190 ° C. and a load of 21.6 kg is 2 g / 10 minutes or more and 20 g / 10 minutes or less.
Characteristic (d2): Density is 0.945 g / cm ³ or more and 0.965 g / cm ³ or less.
Characteristics (d3): Both extension viscosity η (t) (unit: Pa · second) and extension time t (unit: second) measured at a temperature of 170 ° C. and an extension strain rate of 0.1 (unit: 1 / sec) In the log-log plot, the variation point of the extensional viscosity due to strain hardening is observed.
The polyethylene component (D) used in the present invention is preferably produced by a chromium catalyst. As the chromium catalyst, a catalyst in which a chromium compound is supported on an inorganic oxide carrier and at least a part of chromium elements is hexavalent is used. A detailed description of the chromium catalyst is as described in known documents such as Japanese Patent No. 2011-190437.

Characteristic (d1)
The high load melt flow rate (HLMFR) of the polyethylene component (D) used in the present invention is 2 to 20 g / 10 minutes. It is preferably 3 to 10 g / 10 minutes, more preferably 4 to 7 g / 10 minutes. When the HLMFR is 2 g / 10 minutes or more, the fluidity is improved and the desired extrusion characteristics can be obtained, which is preferable. On the other hand, when HLMFR is 20 g / 10 minutes or less, desired durability can be obtained, which is preferable.
The HLMFR of the polyethylene component (D) can be adjusted mainly by the amount of hydrogen at the time of production of the component (D).

Characteristic (d2)
Density polyethylene component used in the present invention (D) is required to be 0.945~0.965g / cm ^3, preferably 0.950~0.960g / cm ^3. A density of 0.945 g / cm ³ or more is preferable because desired rigidity can be obtained. On the other hand, a density of 0.965 g / cm ³ or less is preferable because desired durability can be obtained.
The density of the polyethylene component (D) can be controlled mainly by changing the α-olefin content of the component (D), and the α-olefin content is the polymerization reaction during the production of the component (D). It can be controlled by changing the ratio of the amount of α-olefin and the amount of ethylene in the vessel.

Characteristic (d3)
The polyethylene component (D) has an extensional viscosity η (t) (unit: Pa · second) and an extension time t (unit: second) measured at a temperature of 170 ° C. and an extension strain rate of 0.1 (unit: 1 / sec). In both logarithmic plots, the variation point of the extensional viscosity due to strain hardening is observed, and the strain hardening degree (λmax) is usually preferably 1.05 to 5.00.
The polyethylene component (D) used in the present invention preferably has a long-chain branched structure. When the polyethylene component (D) has a long-chain branched structure, it becomes easy to observe an inflection point of extensional viscosity due to strain hardening in the polyethylene resin composition of the present invention. By observing the inflection point, the crystallization rate can be extremely effectively increased in the polyethylene resin composition, which has the effect of improving the molding cycle.
In the present specification, the presence or absence of an inflection point of extensional viscosity due to strain hardening can be observed in the measurement of strain hardening degree.
Regarding the method for measuring the degree of strain hardening, if the uniaxial extensional viscosity can be measured, the same value can be obtained in principle by any method. Details are given.

In measuring polyethylene according to the present invention, the following can be mentioned as preferable measuring methods and measuring instruments.
Measuring method:
-Device: Ares manufactured by Rheometrics
・ Jig: Exhibitional Viscosity Fixture manufactured by TA Instruments Co., Ltd.
・ Measurement temperature: 170 ℃
-Strain rate: 0.1 / sec-Preparation of test piece: Press-mold to prepare a sheet of 18 mm x 10 mm and thickness of 0.7 mm.

The inflection point of extensional viscosity and the degree of strain hardening (λmax) due to strain hardening can be obtained as follows.
Calculation method:
The extensional viscosity at 170 ° C. and a strain rate of 0.1 / sec is plotted on a log-log graph with time t (seconds) on the horizontal axis and extensional viscosity η (Pa · sec) on the vertical axis. On both logarithmic graphs, the maximum extensional viscosity after strain curing until the strain amount reaches 4.0 is defined as η _Max (t1) (t1 is the time when the maximum extensional viscosity is shown), and the extensional viscosity before strain curing. When the approximate straight line of is η _Linear (t), the _{value calculated as η Max} (t1) / η _Linear (t1) is defined as the strain hardening degree (λmax). The presence or absence of strain hardening is determined by whether or not the extensional viscosity has an inflection point in which the extensional viscosity changes from an upwardly convex curve to a downwardly convex curve with the passage of time.

1 and 2 are plots of typical extensional viscosities. FIG. 1 shows an inflection point of extensional viscosity, and η _Max (t1) and η _Linear (t1) are shown in the figure. FIG. 2 shows a case where an inflection point of extensional viscosity is not observed.

Further, the polyethylene component (D) preferably satisfies the following property (d4).
Property (d4): The molecular weight distribution (Mw / Mn) measured by gel permeation chromatography (GPC) is more than 7 and 50 or less, preferably more than 7 and 40 or less, and more preferably more than 7 and 30 or less. is there.
The molecular weight distribution (Mw / Mn) measured by GPC is related to the improvement of various physical properties and moldability of the polymer, and is also related to the improvement of the appearance and the like of the molded product.
When the molecular weight distribution (Mw / Mn) of the polyethylene component (D) used in the present invention is within the above range, more excellent hollow molding processability can be exhibited. Further, when the molecular weight distribution (Mw / Mn) exceeds 7, the viscosity of the polyethylene component (D) in the low strain rate range becomes high, and the viscosity of the final resin composition in the low strain rate range can be increased. , The compatibility with the polyethylene component (A) is better and the product appearance is excellent, the resin pressure during extrusion molding is appropriate, and the flow instability phenomenon such as sharkskin is less likely to occur, resulting in poor appearance. It is preferable because it is easy to suppress. On the other hand, when the molecular weight distribution (Mw / Mn) is 50 or less, it is easy to suppress deterioration of the pinch-off shape of the molded product, and it is easy to improve the impact strength of the hollow molded product.
The molecular weight distribution can be set within a predetermined range by adopting a catalyst capable of controlling the molecular weight distribution and appropriate polymerization conditions. Further, in the case of a bimodal or multimodal polymer, it can be controlled by adjusting the molecular weight of each component.

The molecular weight (weight average molecular weight Mw, number average molecular weight Mn) and molecular weight distribution can be measured by gel permeation chromatography (GPC) under the following conditions.
[Measurement condition]
Model used: Alliance GPCV2000 type manufactured by Japan Waters Corp. Measurement temperature: 145 ° C
Solvent: Ortodichlorobenzene (ODCB)
Column: Showa Denko Shodex HT-806M x 2 + HT-G
Flow velocity: 1.0 mL / min Injection volume: 0.3 mL

[Sample preparation]
A 4 mL vial was weighed with 3 mg of sample and 3 mL of ortodichlorobenzene (containing 0.1 mg / mL 1,2,4-trimethylphenol) and capped with a resin screw cap and a Teflon® septum. After that, melting is carried out for 2 hours using an SSC-9300 type high temperature shaker manufactured by Senshu Kagaku Co., Ltd. set at a temperature of 150 ° C. After the dissolution is completed, visually confirm that there are no insoluble components.
[Creation of calibration curve]
Prepare four 4 mL glass bottles, weigh 0.2 mg each of the monodisperse polystyrene standard sample or n-alcan of the combination of (1) to (4) below, and then weigh orthodichlorobenzene (0.1 mg / mL). Weighed 3 mL (including 1,2,4-trimethylphenol), covered with a resin screw cap and a Teflon (registered trademark) septum, and then set the temperature to 150 ° C. SSC-9300 manufactured by Senshu Kagaku Co., Ltd. Melt for 2 hours using a high temperature shaker.
(1) Shodex S-1460, S-66.0, n-eicosane (2) Shodex S-1950, S-152, n-tetracontane (3) Shodex S-3900, S-565, S -5.05
(4) Shodex S-7500, S-1010, S-28.5
A vial containing the sample solution is set in the device, measurement is performed under the above conditions, and a chromatogram (retention time and response data set of the differential refractometer detector) is recorded at a sampling interval of 1 second. The retention time (peak apex) of each polystyrene standard sample is read from the obtained chromatogram and plotted against the logarithmic value of the molecular weight. Here, the molecular weights of n-icosane and n-tetracontane are 600 and 1200, respectively. The nonlinear least squares method is applied to this plot, and the obtained quadratic curve is used as the calibration curve.

[Calculation of molecular weight]
The measurement is performed under the above conditions, and the chromatogram is recorded at a sampling interval of 1 second.
From this chromatogram, Sadao Mori, "Size Exclusion Chromatography" (Kyoritsu Shuppan), Chapter 4, p. The differential molecular weight distribution curve and the average molecular weight value (Mn, Mw and Mz) are calculated by the method described in 51-60. However, in order to correct the molecular weight dependence of dn / dc, the height H from the baseline in the chromatogram is corrected by the following formula. Chromatogram recording (data acquisition) and average molecular weight calculation are performed using an in-house program (created with Microsoft Visual Basic 6.0) on a PC on which Microsoft OS Windows (registered trademark) XP is installed.
H'= H / [1.032 + 189.2 / M (PE)]
The following formula is used for the molecular weight conversion from polystyrene to polyethylene.
M (PE) = 0.468 x M (PS)

<Manufacturing method of polyethylene component (D)>
The polyethylene component (D) is a copolymerization of ethylene or an α-olefin having 3 to 12 carbon atoms with ethylene, for example, propylene, 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-. Obtained by copolymerization with octene or the like. In addition, copolymerization with a diene is also possible for the purpose of modification. Examples of the diene compound used at this time include butadiene, 1,4-hexadiene, ethylidene norbornene, dicyclopentadiene and the like.
The comonomer content during the polymerization of the polyethylene component (D) can be arbitrarily selected. For example, the α-olefin content in the ethylene polymer is 0 to 20 mol%, preferably 0. It is 10 mol%.

As the polymerization catalyst of the polyethylene component (D), a chromium catalyst is used as described above.

As a production process, the polyethylene component (D) can be produced by a production process such as a vapor phase polymerization method, a solution polymerization method, or a slurry polymerization method, and among them, a vapor phase polymerization method or a slurry polymerization method is preferable. Among the polymerization conditions of the ethylene polymer, the polymerization temperature can be selected from the range of 0 to 300 ° C. In slurry polymerization, polymerization is carried out at a temperature lower than the melting point of the produced polymer. The polymerization pressure can be selected from the range of atmospheric pressure to about 10 MPa. Selected from aliphatic hydrocarbons such as hexane and heptane, aromatic hydrocarbons such as benzene, toluene and xylene, and alicyclic hydrocarbons such as cyclohexane and methylcyclohexane with substantially no oxygen or water. It can be produced by performing slurry polymerization of ethylene and α-olefin in the presence of an inert hydrocarbon solvent.

In slurry polymerization, hydrogen supplied to the polymer is consumed as a chain transfer agent to determine the average molecular weight of the polyethylene component (ethylene-based polymer) produced, and a part of it is dissolved in a solvent and discharged from the polymer. To. The solubility of hydrogen in the solvent is low, and the hydrogen concentration near the polymerization active site of the catalyst is low unless a large amount of gas phase parts are present in the polymerizer. Therefore, if the hydrogen supply amount is changed, the hydrogen concentration at the polymerization active point of the catalyst changes rapidly, and the molecular weight of the polyethylene component produced changes following the hydrogen supply amount in a short period of time. Therefore, if the hydrogen supply amount is changed in a short cycle, a more homogeneous product can be produced. For this reason, it is preferable to adopt the slurry polymerization method as the polymerization method. Further, it is preferable to change the hydrogen supply amount discontinuously rather than continuously because the effect of widening the molecular weight distribution can be obtained.
In the polyethylene component (D) used in the present invention, it is important to change the hydrogen supply amount as described above, but other polymerization conditions such as polymerization temperature, catalyst supply amount, and olefin supply amount such as ethylene are used. It is also important to appropriately change the supply amount of comonomer such as 1-hexene, 1-hexene, etc. at the same time as or separately from the change of hydrogen.

The polyethylene component (D) can be composed of a plurality of components. The polyethylene component (D) may be a polymer that is sequentially and continuously polymerized in a multi-stage polymerization reactor using one type of catalyst, or a polymer produced in a multi-stage polymerization reactor using a plurality of types of catalysts. But it may be.

A specific preferable polymerization method of the polyethylene component (D) is the following method. That is, it is a method of producing a polymer by introducing ethylene and α-olefin into the reactor using a chromium catalyst and a single-tank or multi-tank reactor.
In the case of multi-stage polymerization, the amount of ethylene-based polymer produced in the second and subsequent stages of polymerization and its properties are determined by determining the amount of polymer produced in each stage (which can be grasped by unreacted gas analysis, etc.). The physical properties of the polymer extracted after each stage can be measured, and the physical properties of the polymer produced in each stage can be determined based on the additivity.

<Polyethylene component (E)>
The polyethylene component (E) used in the polyethylene resin composition of the present invention is polyethylene that satisfies the following properties (e1) to (e2).
Characteristics (e1): Melt flow rate (MFR) at a temperature of 190 ° C. and a load of 2.16 kg is 10 g / 10 minutes or more and 200 g / 10 minutes or less.
Characteristics (e2): density of 0.960 g / cm ³ or more 0.980 g / cm ³ or less.
The polyethylene component (E) of the present invention is produced by a metallocene catalyst or a Ziegler catalyst. As the metallocene catalyst or the Ziegler catalyst, the same catalysts as those used for producing the polyethylene component (A) can be used as described above.
The polyethylene component (E) has a molecular weight distribution (Mw / Mn) of usually 2 to 25 as measured by gel permeation chromatography (GPC) as the polyethylene produced by the metallocene catalyst, and is produced by the Cheegler catalyst. As the polyethylene, the molecular weight distribution (Mw / Mn) measured by gel permeation chromatography (GPC) is usually 6 to 25, and the polyethylene produced by the metallocene catalyst and the polyethylene produced by the Cheegler catalyst have a temperature. For strain hardening in both logarithmic plots of elongation viscosity η (t) (unit: Pa · sec) and elongation time t (unit: sec) measured at 170 ° C. and elongation strain rate 0.1 (unit: 1 / sec). Polyethylene is preferable because no bending point of elongation viscosity due to the observation is observed.

Characteristic (e1):
The melt flow rate (MFR) of the polyethylene component (E) at a temperature of 190 ° C. and a load of 2.16 kg is 10 g / 10 minutes or more and 200 g / 10 minutes. It is preferably 10 to 100 g / 10 minutes, more preferably 10 to 30 g / 10 minutes. When the MFR is 10 g / 10 minutes or more, the fluidity is improved and the desired extrusion characteristics can be obtained, which is preferable. On the other hand, when the MFR is 200 g / 10 minutes or less, the desired durability can be obtained, which is preferable.
In this specification, the MFR of the polyethylene component and the polyethylene resin composition can be measured in accordance with JIS K6922-2: 1997.
The MFR of the polyethylene component (E) can be adjusted mainly by the amount of hydrogen at the time of production of the component (E).

Characteristic (e2):
Density polyethylene component (E) is required to be 0.960~0.980g / cm ^3, preferably 0.960~0.975g / cm ^3, more preferably 0.960~0.970g / Cm ³ . A density of 0.960 g / cm ³ or more is preferable because the desired rigidity can be obtained. On the other hand, a density of 0.980 g / cm ³ or less is preferable because desired durability can be obtained.
The density of the polyethylene component (E) can be adjusted mainly by the amount of α-olefin in the production of the component (E).

<Manufacturing method of polyethylene component (E)>
The polyethylene component (E) is a copolymerization of ethylene or an α-olefin having 3 to 12 carbon atoms with ethylene, for example, propylene, 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-. Obtained by copolymerization with octene or the like. In addition, copolymerization with a diene is also possible for the purpose of modification. Examples of the diene compound used at this time include butadiene, 1,4-hexadiene, ethylidene norbornene, dicyclopentadiene and the like.
The comonomer content during the polymerization of the polyethylene component (E) can be arbitrarily selected. For example, the α-olefin content in the polyethylene component (E) is 0 to 40 mol%, preferably 0 to 40 mol%. It is 0 to 30 mol%.

As the polymerization catalyst of the polyethylene component (E), as described above, a metallocene catalyst or a Ziegler-based catalyst is used.

As a production process, the polyethylene component (E) can be produced by a production process such as a gas phase polymerization method, a solution polymerization method, or a slurry polymerization method, and among them, a vapor phase polymerization method or a slurry polymerization method is preferable. Among the polymerization conditions of the polyethylene component (E), the polymerization temperature can be selected from the range of 0 to 300 ° C. In slurry polymerization, polymerization is carried out at a temperature lower than the melting point of the produced polymer. The polymerization pressure can be selected from the range of atmospheric pressure to about 10 MPa. Selected from aliphatic hydrocarbons such as hexane and heptane, aromatic hydrocarbons such as benzene, toluene and xylene, and alicyclic hydrocarbons such as cyclohexane and methylcyclohexane with substantially no oxygen or water. It can be produced by performing slurry polymerization of ethylene and α-olefin in the presence of an inert hydrocarbon solvent.

In the slurry polymerization, hydrogen supplied to the polymer is consumed as a chain transfer agent to determine the average molecular weight of the polyethylene component to be produced, and a part of the hydrogen is dissolved in a solvent and discharged from the polymer. The solubility of hydrogen in the solvent is low, and the hydrogen concentration near the polymerization active site of the catalyst is low unless a large amount of gas phase parts are present in the polymerizer. Therefore, if the hydrogen supply amount is changed, the hydrogen concentration at the polymerization active point of the catalyst changes rapidly, and the molecular weight of the polyethylene component produced changes following the hydrogen supply amount in a short period of time. Therefore, if the hydrogen supply amount is changed in a short cycle, a more homogeneous product can be produced. For this reason, it is preferable to adopt the slurry polymerization method as the polymerization method. Further, it is preferable to change the hydrogen supply amount discontinuously rather than continuously because the effect of widening the molecular weight distribution can be obtained.
In the polyethylene component (E), as described above, it is important to change the hydrogen supply amount, but other polymerization conditions such as polymerization temperature, catalyst supply amount, supply amount of olefin such as ethylene, 1-hexene and the like. It is also important to appropriately change the supply amount of the comonomer, the supply amount of the solvent, etc. at the same time as or separately from the change of hydrogen.

The polyethylene component (E) can be composed of a plurality of components. The polyethylene component (E) may be a polymer that is sequentially and continuously polymerized in a multi-stage polymerization reactor using one type of catalyst, or a polymer produced in a multi-stage polymerization reactor using a plurality of types of catalysts. But it may be.

Further, another specific preferable polymerization method of the polyethylene component (E) is the following method. That is, using a Ziegler catalyst containing a titanium-based transition metal compound and an organoaluminum compound and a single reactor, ethylene, hydrogen and, if necessary, α-olefin are introduced into the reactor to have a predetermined density and MFR. This is a method for producing a polymer.
In the case of multi-stage polymerization, the amount of polyethylene component produced in the second and subsequent stages of polymerization and its properties are determined by determining the amount of polymer produced in each stage (which can be grasped by unreacted gas analysis, etc.), and each stage. After that, the physical properties of the extracted polymers can be measured, and the physical properties of the polymers produced in each stage can be determined based on the additivity.

<Polyethylene resin composition>
In the polyethylene resin composition of the present invention, the polyethylene component (A) is 10% by mass or more and 40% by mass or less, the polyethylene component (D) is 5% by mass or more and 50% by mass or less, and the polyethylene component (E) is 40% by mass. It contains% or more and 85% by mass or less, and satisfies the following characteristics (1) to (5).
Characteristic (1): MFR is 0.1 g / 10 minutes or more and 1 g / 10 minutes or less.
Characteristic (2): HLMFR is 10 g / 10 minutes or more and 50 g / 10 minutes or less.
Characteristic (3): The melt flow rate ratio (HLMFR / MFR), which is the ratio of HLMFR to MFR, is 50 or more and 140 or less.
Characteristics (4): density of 0.940 g / cm ³ or more 0.965 g / cm ³ or less.
Characteristic (5): Both extension viscosity η (t) (unit: Pa · second) and extension time t (unit: second) measured at a temperature of 170 ° C. and an extension strain rate of 0.1 (unit: 1 / sec). In the log-log plot, the variation point of the extensional viscosity due to strain hardening is observed.

In the polyethylene resin composition of the present invention, the compounding amount ratio of the polyethylene component (A) to the polyethylene components (D) and (E) is such that the polyethylene component (A) is 10% by mass or more and 40% by mass or less, and the polyethylene component (D). ) Is 5% by mass or more and 50% by mass or less, the polyethylene component (E) is 40% by mass or more and 85% by mass or less, preferably the polyethylene component (A) is 15% by mass or more and 40% by mass or less, and the polyethylene component (D). ) Is 10% by mass or more and 30% by mass or less, the polyethylene component (E) is 40% by mass or more and 70% by mass or less, and more preferably, the polyethylene component (A) is 20% by mass or more and 40% by mass or less, and the polyethylene component (). A composition containing 10% by mass or more and 25% by mass or less of D) and 40% by mass or more and 70% by mass or less of the polyethylene component (E). When the component (A) is 10% by mass or more, the content of the high molecular weight component in the polyethylene resin composition is improved, and desired impact strength, stress crack resistance, and the like can be obtained, which is preferable. On the other hand, when the component (A) is 40% by mass or less, the fluidity is improved and the desired extrudability can be obtained, which is preferable.

Characteristics (1)
The polyethylene resin composition of the present invention has an MFR of 0.1 g / 10 minutes or more and 1 g / 10 minutes or less. The MFR is preferably in the range of 0.15 g / 10 minutes or more and 0.8 g / 10 minutes or less, more preferably 0.2 g / 10 minutes or more and 0.6 g / 10 minutes or less, and particularly preferably 0.25 g / 10 minutes or less. The range is 0.50 g / 10 minutes or less.
When this MFR is 0.1 g / 10 minutes or more, the fluidity is improved, so that the flow instability phenomenon such as shark skin and melt fracture is less likely to occur, so that the appearance of the molded product can be improved. ..
On the other hand, when this MFR is 1 g / 10 minutes or less, impact resistance and environmental stress crack resistance can be achieved, and drop impact resistance and long-term durability of the molded product are improved.
The MFR of the polyethylene resin composition can be adjusted by adjusting the amount and temperature of hydrogen at the time of polymerization of the polyethylene component (A), the polyethylene component (D) and the polyethylene component (E), and the blending amount of each component.
MFR can be measured in the same manner as described above.

Characteristics (2)
The polyethylene resin composition of the present invention has an HLMFR of 10 g / 10 minutes or more and 50 g / 10 minutes or less. The HLMFR is preferably in the range of 20 g / 10 minutes or more and 35 g / 10 minutes or less, and more preferably 25 g / 10 minutes or more and 30 g / 10 minutes or less.
If this HLMFR is 10 g / 10 minutes or more, the fluidity can be improved to reduce the resin calorific value due to the extruder motor load and shearing during molding, and the fluidity of sharkskin and melt fracture is poor. Since the stabilization phenomenon is less likely to occur, the appearance of the molded product can be improved.
On the other hand, when this HLMFR is 50 g / 10 minutes or less, impact resistance and environmental stress crack resistance can be achieved, and drop impact resistance and long-term durability of the molded product can be improved.
The HLMFR of the polyethylene resin composition can be adjusted by adjusting the amount and temperature of hydrogen at the time of polymerization of the polyethylene component (A), the polyethylene component (D) and the polyethylene component (E), and the blending amount of each component.
HLMFR can be measured in the same manner as described above.

Characteristics (3)
The polyethylene resin composition of the present invention has a melt flow rate ratio (HLMFR / MFR), which is a ratio of HLMFR to MFR, of 50 or more and 140 or less. The melt flow rate ratio is preferably in the range of 51 or more and 130 or less, and more preferably 52 or more and 120 or less.
HLMFR / MFR has a strong correlation with the molecular weight distribution, and when HLMFR / MFR takes a large value, the molecular weight distribution becomes wide, and when HLMFR / MFR takes a small value, the molecular weight distribution becomes narrow. When HLMFR / MFR is 140 or less, the compatibility of each component becomes good, and effects such as improvement of pinch-off moldability and improvement of impact resistance can be obtained. Further, when HLMFR / MFR is 50 or more, effects such as improvement of melting tension, less likely occurrence of flow instability phenomenon such as shark skin, and improvement of ESCR can be obtained.
The method for controlling HLMFR / MFR can be performed mainly according to the method for controlling the molecular weight distribution.

Characteristics (4)
Polyethylene resin composition of the present invention, density of 0.940 g / cm ³ or more 0.965 g / cm ³ or less. The density is preferably in the range of ^{0.950 g / cm 3} or more and 0.960 g / cm ^{3 or less.}
When the density is 0.940 g / cm ³ or more, the desired rigidity can be obtained. On the other hand, when the density is 0.965 g / cm ³ or less, the durability can be improved.
The density can be adjusted mainly by the amount of α-olefin at the time of polymerization of the polyethylene component (A), the polyethylene component (D) and the polyethylene component (E), and can be adjusted by the blending amount of each component. it can.
The density can be measured in the same manner as described above.

Characteristics (5)
The polyethylene resin composition of the present invention has an extensional viscosity η (t) (unit: Pa · sec) and an extension time t (unit: unit:) measured at a temperature of 170 ° C. and an extension strain rate of 0.1 (unit: 1 / sec). In the double logarithmic plot of (seconds), the variation point of the extensional viscosity due to strain hardening is observed.
The presence or absence of an inflection point of extensional viscosity due to strain hardening can be observed in the measurement of strain hardening degree, and can be measured by the same method as the method for measuring strain hardening degree of the polyethylene component (D) described above. it can.

Characteristics (6)
The polyethylene resin composition of the present invention preferably further satisfies the following property (6).
Property (6): The rupture time (FNCT) at 80 ° C. and 3.7 MPa according to the full notch creep test is 285 hours or more.
The longer the full notch creep test (FNCT) time, the better the long-term durability such as environmental stress crack resistance. A fracture time (FNCT) of 285 hours or more is preferable from the viewpoint of particularly excellent balance between rigidity (density) and long-term durability such as environmental stress crack resistance. The breaking time (FNCT) is obtained from the following relational expression (1).
log (FNCT) ≧ -257.5 × (density) + 247.9 Relational expression (1)
The full notch creep test can be performed according to ISO DIS 16770. For the sample, a test piece having a 1 mm notch with a razor blade and a cross section having a size of 4 mm × 4 mm was prepared around the entire circumference of a prism having a size of 6 mm × 6 mm × 11 mm, and pure water at 80 ° C. Among them, a tensile stress corresponding to 3.7 MPa is applied to the sample, and the time until the sample breaks is measured and used as the breaking time of FNCT.
In order for the polyethylene resin composition of the present invention to satisfy the characteristic (6), the polyethylene component (A), the polyethylene component (D) and the polyethylene component (E) having specific physical properties are mixed in a predetermined blending ratio. It is preferable to do so.

Characteristics (7)
The polyethylene resin composition of the present invention preferably further satisfies the following property (7).
Characteristic (7): The tensile impact strength is 233 kJ / m ² or more. It is preferably 250 kJ / m ² or more, and more preferably 280 kJ / m ² or more.
The polyethylene resin composition of the present invention preferably has a tensile impact strength of 233 kJ / m ² or more. The tensile impact strength referred to here is measured based on ASTM D1822-68. When the tensile impact strength is 233 kJ / m ² or more, the impact resistance as a container tends to be improved. The tensile impact strength can be adjusted by the density of polyethylene, and the tensile impact strength can be increased by decreasing the density. Further, the tensile impact strength can be adjusted by the MFR and HLMFR of the polyethylene resin composition, and the tensile impact strength can be increased by lowering the MFR and HLMFR.

It is preferable that the polyethylene resin composition of the present invention further satisfies the following property (8) from the viewpoint of hollow moldability such as drawdown resistance.
Characteristic (8): The melt tension (MT) measured at 190 ° C. is 40 mN or more.
The melt tension is more preferably 65 mN or more. Further, it is preferable that the melting tension corresponding to the HLMFR is high and that the following relational expression (2) is satisfied, and further that the following relational expression (3) is satisfied.
MT> -22.45 × ln (HLMFR) +137.82 Relational expression (2)
MT> -22.45 x ln (HLMFR) +157.82 Relational expression (3)
Here, MT (mN) is the melt tension, HLMFR (g / 10 minutes) is the melt flow rate at a temperature of 190 ° C. and a load of 21.6 kg.
In the present invention, when HLMFR is plotted on the horizontal axis and melt tension is plotted on the vertical axis, the example data of the present invention is plotted, and the relational expression (2) is a mathematical formula for distinguishing the preferable range of the present invention from the prior art. Yes, the relational expression (3) is a mathematical expression for defining a more preferable range of the present invention.
The melt tension is determined by measuring the stress when the melted ethylene polymer is stretched at a constant speed, and can be measured under the following conditions.
[Measurement condition]
Model used: Capillograph 1B manufactured by Toyo Seiki Seisakusho Co., Ltd.
Nozzle diameter: 2.095 mm
Nozzle length: 8.0 mm
Inflow angle: 180 ° (flat)
Extrusion speed: 15 mm / min Pick-up speed: 6.5 m / min Measurement temperature: 190 ° C
In order for the polyethylene resin composition of the present invention to satisfy the property (8), the polyethylene component (A), the polyethylene component (D), and the polyethylene component (E) having specific physical properties are mixed in a predetermined blending ratio. Is preferable.

Further, the polyethylene component (A), the polyethylene component (D), the polyethylene component (E) or the polyethylene resin composition is an additive added to ordinary polyolefin as needed within a range not impairing the object of the present invention. May be contained. These additives can be used alone or in combination of two or more.
Examples of the additive include stabilizers such as heat-resistant stabilizers and weather-resistant stabilizers, cross-linking materials, cross-linking aids, antistatic agents, slip agents, anti-blocking agents, antifogging agents, lubricants, dyes, pigments, fillers, and the like. Examples include mineral oil-based softeners, petroleum resins, and waxes.

According to the polyethylene resin composition of the present invention, since it is a polyethylene material having the above-mentioned properties (1) to (4), it is excellent in hollow moldability, environmental stress crack resistance and impact resistance, and is thinner and lighter. It can be molded by molding, has excellent high-speed moldability, can be molded in high cycle, has good pinch-off characteristics, and has high compatibility of resin components, especially for the appearance of the molded product. It is possible to obtain an excellent molded product.
Further, preferably, a polyethylene resin composition having one or more of the above-mentioned properties (5) to (8) in addition to the above-mentioned properties (1) to (4) further exerts the above-mentioned effect even better.
Further, by using the specific polyethylene component (A) together with the specific polyethylene component (D) and the component (E), an ethylene polymer composition using a conventional chromium-based catalyst or a Ziegler-based catalyst can be obtained. The environmental stress crack resistance can be further improved as compared with the ethylene-based polymer composition used and the ethylene-based polymer composition in which they are mixed.

Generally, polyethylene is processed into an industrial product by a molding method such as film molding, blow molding, foam molding, etc. via a molten state. At this time, the extensional flow characteristics typified by the above-mentioned extensional viscosity and strain hardening degree. Is well known to have a significant effect on the ease of molding.
That is, polyethylene having a narrow molecular weight distribution and no long-chain branching has poor meltability due to its low melt strength, while polyethylene having an ultra-high molecular weight component or long-chain branching component is strain-cured during melt elongation (strain). Hardening), that is, polyethylene having a property that the extensional viscosity sharply increases on the high strain side, and which exhibits this property remarkably, is said to be excellent in moldability. A polyethylene resin having such elongation-flow characteristics can, for example, prevent uneven thickness or blow-by of a product in film molding or hollow molding, enable high-speed molding, and increase the closed cell ratio during foam molding. It is effective and has merits such as improvement of strength of molded product, improvement of design, weight reduction, improvement of molding cycle, improvement of heat insulation, etc. On the other hand, if the elongation flow property of polyethylene is too strong, molecules during molding are obtained. Inconveniences such as a decrease in the impact strength of the molded product occur due to the strength anisotropy presumed to be caused by the orientation.
On the other hand, according to the present invention, as described above, the polyethylene component (D) and the component (E) satisfying the specific physical property balance are used, and the polyethylene component (A) having the specific physical property is composed of the composition. By using it as a low melt flow component, that is, a high molecular weight component of a product, it is excellent in contributing to improvement of rigidity, environmental stress crack resistance, impact resistance, and molding processing characteristics, especially drawdown resistance and pinch-off moldability. It is also excellent in hollow formability, can be formed thinner and lighter, has high melt tension, is excellent in drawdown resistance, and can be hollow formed into a complicated shape.

Since the polyethylene component (D) and the component (E) satisfying the specific physical property balance are used, the polyethylene resin composition is excellent in compatibility of each resin component in the resin composition and particularly excellent in the appearance of the molded product. It becomes a thing.
Above all, when the polyethylene component (A) has a long-chain branched structure, the melt flow rate ratio becomes specific, whereby the polyethylene component (A) is highly dispersed in the polyethylene component (D) and the component (E). Therefore, the compatibility is good. Therefore, in the molded product, the surface texture becomes smooth and the appearance is particularly excellent.
Since the polyethylene resin composition of the present invention is a polyethylene resin composition having the above physical characteristics, it is also excellent in moldability, high fluidity, odor, food safety, rigidity, heat resistance and the like.

<Manufacturing method of polyethylene resin composition>
The method for producing the polyethylene resin composition of the present invention is not particularly limited, and a known method can be applied. For example, the polyethylene component (A), the polyethylene component (D), and the polyethylene component (E) are individually produced, and these are usually produced in the above proportions in an extruder, a Banbury mixer, a roll, a lavender plastograph, a kneader, etc. It can be produced by melt-kneading using the kneading machine of. The temperature for melt-kneading is not particularly limited as long as the polyethylene component (A), polyethylene component (D) and polyethylene component (E) are within the melting range, but it is usually produced by kneading in the range of 180 to 350 ° C. it can. Among these kneaders, a single-screw or twin-screw extruder or a continuous kneader can be used, and it is particularly preferable to manufacture using a twin-screw extruder. After pelletizing by melting and mixing, it can be molded by various molding machines to obtain a desired molded product.

Since the polyethylene resin composition of the present invention produces a molded product, as long as the object of the present invention is not impaired, other olefin-based polymers contained in the molded product made of ordinary polyolefin may be used. In addition to rubber, antioxidants (phenolic, phosphorus, sulfur), UV absorbers, light stabilizers, lubricants, antistatic agents, antifogging agents, antiblocking agents, processing aids, coloring pigments, pearl pigments , Polarized pearl pigments, cross-linking agents, foaming agents, neutralizing agents, heat stabilizers, crystal nucleating agents, inorganic or organic fillers, flame retardants and other known additives can be blended in one or more.
Examples of the organic filler include carbon fiber, carbon black, and carbon nanotube, and examples of the inorganic filler include silica, calcium silicate, alumina, titanium oxide, magnesium oxide, pebbles powder, pebbles balloon, and water. Aluminum oxide, magnesium hydroxide, dolomite, calcium sulfate, potassium titanate, barium sulfate, talc, clay, mica, glass flakes, glass beads, glass fiber, aluminum silicate, calcium silicate, montmorillonite, bentonite, molybdenum sulfide, graphite And so on.
As the filler, calcium carbonate, talc, metal powder (aluminum, copper, iron, lead, etc.), silica stone, diatomaceous earth, alumina, gypsum, mica, clay, asbestos, graphite, carbon black, titanium oxide and the like can be used. ..
In either case, the polyethylene-based resin can be mixed with various additives as necessary and kneaded with a kneading extruder, a Banbury mixer or the like to be used as a molding material.

2. Molded article and container The molded article of the present invention is a molded article prepared by using the polyethylene resin composition according to the present invention.
The container of the present invention is a container made by using the polyethylene resin composition according to the present invention.
The polyethylene resin composition of the present invention can be molded by a known molding method to obtain an arbitrary molded product.
A molded product can be produced by various molding methods using the polyethylene resin composition of the present invention as a raw material. It is preferably molded mainly by a hollow molding method or the like, and various molded products such as a hollow container are preferably obtained.

The polyethylene resin composition of the present invention is suitable for applications such as containers that require such properties, and in particular, cosmetic containers, detergents, shampoo and rinse containers, or edible oils that are required to have a good appearance. It can be suitably used for applications such as food containers such as.

In particular, the container which is a molded product using the polyethylene resin composition of the present invention can be molded at high speed and has a high cycle, has excellent product characteristics, and is economically advantageous, such as detergent, shampoo, and rinse. Suitable as a container for

Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples as long as the gist thereof is not exceeded.

1. 1. Measurement method The measurement method used in the examples is as follows.
(1) Melt flow rate (MFR) at a temperature of 190 ° C. and a load of 2.16 kg:
Measured according to JIS K6922-2: 1997.
(2) Melt flow rate (HLMFR) at a temperature of 190 ° C. and a load of 21.6 kg:
Measured according to JIS K6922-2: 1997.
The HLMFR of the component (B) or the component (C) was determined by correlating the hydrogen concentration during the production of the polyethylene polymer with the HLMFR of the polyethylene polymer in the case of a small amount of batch polymerization.
In the case of polymerizing in a large amount, the polyethylene polymer was extracted from the reaction vessel in the first reaction step, and the HLMFR of the polyethylene polymer of the component (B) was measured. Then, the polyethylene polymer was extracted from the reaction vessel in the second reaction step, the HLMFR of the polyethylene polymer of the component (A) was measured, and the weight% was between the HLMFR after the second reaction step and the HLMFR after the first reaction step. I sought to establish the additiveness of.
(3) Density:
Measured according to JIS K6922-1, 2: 1997.
The density of the component (B) or the component (C) was determined by correlating the α-olefin concentration during the production of the polyethylene polymer with the density of the polyethylene polymer in the case of a small amount of batch polymerization.
In the case of polymerizing in a large amount, the polyethylene polymer was extracted from the reaction vessel in the first reaction step, and the density of the polyethylene polymer of the component (B) was measured. Then, the polyethylene polymer was extracted from the reaction vessel of the second reaction step, the density of the polyethylene polymer of the polyethylene resin composition was measured, and the mass% was between the density after the second reaction step and the density after the first reaction step. I sought to establish the additiveness of.

(4) Content ratio of polyethylene component (B) Polyethylene is based on the ratio of the amounts of ethylene and comonomer, which are the raw materials consumed in the first-stage reactor and the second-stage reactor, in the manufacturing process of the polyethylene component (A) described later. The content ratio of the polyethylene component (B) contained in the component (A) was calculated.

(5) Fracture time in full notch creep test (FNCT) (measured at 80 ° C. and 3.7 MPa):
The measurement was carried out at 80 ° C. and 3.7 MPa according to the all-around notch type tensile creep test of Annex 1 of JIS K6774 (1995). The test piece was cut out from a compression molded sheet having a thickness of 6 mm prepared under the conditions shown in Table 2 of JIS K6922-2 (1997) and had a notch on the entire circumference (test piece thickness 6 mm, notch depth 1 mm, all circumference). It was used. Pure water was used as the test solution for immersing the sample.

(6) Melt tension:
The melt tension (MT) was determined by measuring the stress when the melted ethylene polymer was stretched at a constant speed, and was measured under the following conditions.
[Measurement condition]
Model used: Capillograph 1B manufactured by Toyo Seiki Seisakusho Co., Ltd.
Nozzle diameter: 2.095 mm
Nozzle length: 8.0 mm
Inflow angle: 180 ° (flat)
Extrusion speed: 15 mm / min Pick-up speed: 6.5 m / min Measurement temperature: 190 ° C

(7) Tensile impact strength (TIS)
A 1.5 mm compression molded sheet was prepared according to JIS K6922-2, and a test piece punched out with an S-type dumbbell was prepared according to ASTM D1822, and tensioned at 23 ° C. and 50% RH. Impact strength (unit: kJ / m ² ) was measured.

(8) Pinch-off characteristics:
For the measurement of tan δ at 150 ° C. and 100 rad / sec measured by a rheometer, a sample adjusted by a hot press was used, and a rheometer (Ares manufactured by Rheometerics) was used to measure the storage elastic modulus G'at 150 ° C. and an angular velocity of 100 rad / sec. And the loss elastic modulus G "were measured, and tan δ (= G'/ G') was calculated. The conditions at the time of measurement are described below.
[Measurement condition]
Equipment: Ares manufactured by Rheometrics
Jig: Diameter 25mm parallel plate, plate spacing about 1.7mm
Measurement temperature: 150 ° C
Distortion: 10%

(9) Hollow moldability With a single-layer direct blow molding machine (manufactured by Blends Co., Ltd., screw diameter = φ70 mm, L / D = 24, compression ratio (CR) = 3.0), a constant pinch-off width is achieved. Using a straight die with an arbitrary die core diameter, adjust the molding resin temperature to about 210 ° C. under the condition of a screw rotation speed of 10 rpm, extrude a parison, and shape a flat container of about 400 ml (length about 19 cm, width about 7 cm, maximum depth about). Blow mold (cavity surface blast finish, cavity surface roughness Ra value 0.7 μm mold), mold of 5 cm, outer diameter about 2 cm, height about 2 cm with screw-shaped mouth) Blow molding was performed in the range of a mold temperature of 20 ° C., a blow pressure of 6 kg / cm2, a container weight of about 30 g, and a molding cycle of about 10 to 12 seconds. If the container can be molded within the above conditions, the hollow moldability is "good (○)", holes are formed at the fusion interface during blow-up, and a molded product with a uniform wall thickness distribution can be obtained due to remarkable drawdown, etc. Those that were difficult were designated as "defective (x)".

(10) Appearance of molded product The appearance of the container, which is a blow-molded product obtained in the above hollow molding evaluation, is evaluated by visual judgment, and the one having a uniform and uniform skin feeling or a product close to it is "good (good). ○) ”, Others, such as those with flow marks or no uniform skin feeling, those with poor air bleeding in the mold cavity, those with melt fracture in the parison, and those with the surface of the parison Those with finely rough skin, those with reduced transparency due to transfer of the mold cavity surface, etc. were classified as "defective (x)".

(11) Presence or absence of long-chain branched structure (presence or absence of rise in extensional viscosity):
Measurement of extensional viscosity at 170 ° C. and strain rate 0.1 / sec using a rheometer (Ares manufactured by Rheometerics) using a test piece prepared in the form of a sheet of 18 mm × 10 mm and a thickness of 0.7 mm by press molding. The presence or absence of the long-chain branched structure was confirmed by the presence or absence of the rise of the extensional viscosity (presence or absence of strain hardening).
[Measurement condition]
Equipment: Ares manufactured by Rheometrics
Jig: Industrial Viscosity Fixture manufactured by TA Instruments Co., Ltd.
Measurement temperature: 170 ° C
Strain rate: 0.1 / sec Preparation of test piece: A sheet having a size of 18 mm × 10 mm and a thickness of 0.7 mm was prepared by press molding.
[Calculation method]
The extensional viscosity at 170 ° C. and a strain rate of 0.1 / sec was plotted on a log-log graph with time t (unit: seconds) on the horizontal axis and extensional viscosity η (t) (unit: Pa · sec) on the vertical axis. On both logarithmic graphs, the maximum extensional viscosity after strain curing until the strain amount reaches 4.0 is defined as η _Max (t1) (t1 is the time when the maximum extensional viscosity is shown), and the extensional viscosity before strain curing. When the approximate straight line of is η _Linear (t), the _{value calculated as η Max} (t1) / η _Linear (t1) is defined as the strain hardening degree (λmax). The presence or absence of strain hardening was determined by whether or not the extensional viscosity had an inflection point in which the extensional viscosity changed from an upwardly convex curve to a downwardly convex curve with the passage of time.
1 and 2 are plots of typical extensional viscosities. FIG. 1 shows an inflection point of extensional viscosity, and η _Max (t1) and η _Linear (t1) are shown in the figure. FIG. 2 shows a case where an inflection point of extensional viscosity is not observed.

(12) Comprehensive evaluation The hollow moldability as an ethylene / α-olefin copolymer and the suitability as a hollow molded product were comprehensively evaluated. That is, those satisfying any of the following items were regarded as "good (○)", and those other than that were regarded as "poor (x)".
1) In the evaluation of the pinch-off characteristic, tan δ is 0.50 to 0.80.
2) The tensile impact strength is 233 kJ / m ² or more.
3) FNCT is 285 hours or more.
4) Good hollow moldability.
5) The appearance of the molded product is good.

2. Materials used (1) Synthesis of metallocene catalyst In a cylindrical flask equipped with an induction stirrer fully substituted with nitrogen, silica having an average particle size of 11 μm (average particle size 11 μm, surface area 313 m ² / g, pore volume 1. 6 cm ³ / g) was filled in 3 g, 75 ml of toluene was added, and the mixture was heated to 75 ° C. by an oil bath. In another flask, 8.0 ml of a toluene solution of methylaluminoxane (3.0 mol-Al / L manufactured by Albemarle Corporation) was taken. Dimethylsilylenebis [1,1'-{2- (2- (5-methyl) frill) -4- (p-isopropylphenyl) -indenyl}] Zirconium dichloride (63.4 mg, 75 μmol) in toluene (15 ml) Was added to a toluene solution of methylarmoxane at room temperature, the temperature was raised to 75 ° C., and the mixture was stirred for 1 hour. Next, this toluene solution was added to a toluene slurry of silica heated to 75 ° C. with stirring, and the mixture was held for 1 hour. Then, 175 ml of n-hexane was added while stirring at 23 ° C., and after 10 minutes, stirring was stopped and the mixture was allowed to stand. After the catalyst was sufficiently precipitated, the supernatant was removed and 200 ml of n-hexane was added. After stirring once, the mixture was allowed to stand again to remove the supernatant. This operation was repeated 3 times to remove the component liberated in n-hexane. Further, the solvent was distilled off by reducing the pressure while heating at 40 ° C. After the degree of reduced pressure became 0.8 mmHg or less, drying under reduced pressure was continued for another 15 minutes to obtain a silica-supported metallocene catalyst.

(2) Synthesis of Ziegler catalyst 20 g (17.8 mmol) of commercially available magnesium ethylate (average particle size 860 μm) in a pot (crushing container) having an internal volume of 1 L containing about 700 magnetic balls having a diameter of 10 mm in a nitrogen atmosphere. ), 1.64 g (12.3 mmol) of granular aluminum trichloride and 2.40 g (8.81 mmol) of diphenyldiethoxysilane were added. Then, using a vibrating ball mill, co-milling was performed for 3 hours under the conditions of an amplitude of 6 mm and a frequency of 30 Hz. After co-milling, the contents were separated from the magnetic balls in a nitrogen atmosphere.
10.0 g of the co-grinding product obtained as described above and 40 ml of heptane were added to a 200 ml three-necked flask. While stirring, 10.0 g (52.7 mmol) of titanium tetrachloride was added dropwise at room temperature, the temperature was raised to 90 ° C., and stirring was continued for 90 minutes. Then, after cooling the reaction system, the supernatant was withdrawn and hexane was added. This operation was repeated 3 times. The obtained pale yellow solid was dried at 50 ° C. under reduced pressure for 6 hours to obtain 15.6 g of a solid catalyst.
The hexane slurry solution of this solid catalyst was placed in a polymerization reactor equipped with an induction stirrer, the temperature was maintained at 40 ° C., and 0.27 mmol of triisobutylaluminum was added to a hydrogen partial pressure of 0.074 MPa and an ethylene partial pressure of 0.20 MPa. Prepolymerization was carried out to obtain a prepolymerized Ziegler catalyst having a polymer production amount of 0.46 g per 1 g of the solid catalyst.

(3) Synthesis of Chromium Catalysts Regarding the synthesis of chromium catalysts, detailed descriptions can be found in known documents such as Japanese Patent No. 2011-190437.
For example, an example is shown below. That is, 50 g of silica gel (for example, manufactured by Grace Co., Ltd .; trade name C-952) and 200 mL of ion-exchanged water are added to a 1 L flask equipped with a stirrer, and an aqueous solution prepared by dissolving 2.2 g of chromium (III) acetate in 70 mL of ion-exchanged water is further added. The silica gel was well impregnated with the chromium compound. Next, the mixture was heated to distill off all of the water to obtain greenish white, highly fluid chromium-catalyzed precursor particles. By calcination activation (activation) of these chromium catalyst precursor particles in a calcination electric furnace in a state of flow by a dry air stream, an orange chrome catalyst indicating that it contains hexavalent chromium can be obtained. .. The calcination temperature for activation is generally 350 ° C. to 850 ° C.

(4) Production of Polyethylene Component (D) Dehydrated and Purified Isobutane, the chromium catalyst obtained in (3) above, and ethylene are continuously supplied to a polymerization apparatus having a polymerization liquid-filled loop reactor, and ethylene is ethylene at 105 ° C. The component (D) was produced by polymerizing. The HLMFR of component (D) was adjusted by supplying an appropriate amount of hydrogen.

(5) Production of Polyethylene Component (E) Dehydrated and Purified Isobutane, Triisobutylaluminum, and Prepolymerization Obtained in (2) above were placed in a two-tank continuous polymerization apparatus in which two polymerization liquid-filled loop reactors were connected in series. The component (E) was produced by continuously supplying a Ziegler catalyst and ethylene to polymerize ethylene at 95 ° C. The HLMFR of the component (E) was adjusted by supplying an appropriate amount of hydrogen.

3. 3. Example and Comparative Example [Example 1]
Production of polyethylene component (B);
The component (B) was produced by performing ethylene / 1-hexene copolymerization with the silica-supported metallocene catalyst. That is, in a 2 L autoclave with an induction stirrer, 800 mL of isobutane, 1.0 mL of 1-hexene, 0.10 mmol of triisobutylaluminum, and Stadis450 (a mixture of polysulfone copolymer, high molecular weight polyamine, and oil-soluble sulfonic acid manufactured by The Assisted Octel). 0.8 ml of a toluene diluent (2 g / L) was added, the temperature was raised to 80 ° C., 50 mL of hydrogen was added, and ethylene was further introduced to maintain the ethylene partial pressure at 1.0 MPa. Next, 24 mg of the metallocene catalyst was press-fitted with nitrogen, and the polymerization was continued for 32 minutes while maintaining an ethylene partial pressure of 1.0 MPa and a temperature of 80 ° C. Incidentally, during the polymerization reaction was carried out additional supply of H ₂ and 1-hexene at a delivery rate proportional to the ethylene consumption rate. The HLMFR of the component (B) obtained at this time was 0.72 g / 10 minutes, and the density was 0.9190 g / cm ³ .

Production of polyethylene component (C);
After producing the component (B) as described above, 130 mL of hydrogen was rapidly added while maintaining the temperature and pressure, and ethylene / 1-hexene copolymerization was continued for another 88 minutes to produce the component (C). Incidentally, during the polymerization reaction was carried out additional supply of H ₂ and 1-hexene at a delivery rate proportional to the ethylene consumption rate. The HLMFR of the component (C) obtained at this time was 0.72 g / 10 minutes, and the density was 0.9270 g / cm ³ .

Production of polyethylene component (A);
The component (B) and the component (C) were produced as described above, and continuous polymerization was carried out to produce 247 g of the polyethylene component (A), which is a two-stage polymerized product. The HLMFR of the component (A) was 0.72 g / 10 minutes, and the density was 0.9230 g / cm ³ .

Production of polyethylene resin composition;
The polyethylene resin component (A), the polyethylene component (D), and the polyethylene component (E) were melt-mixed at the ratios shown in Table 1 under the following kneading conditions to produce a polyethylene resin composition. The HLMFR of the composition was 28 g / 10 min and the density was 0.9544 g / cm ³ .
[Kneading conditions]
Equipment used: Labplast Mill Roller Mixer manufactured by Toyo Seiki Seisakusho Co., Ltd. (Mixer model: R100 / Blade shape: Roller type R100B)
Additive formulation: 2,000 ppm of IRGANOX B225 manufactured by BASF Japan and 1,000 ppm of calcium stearate manufactured by Tannan Chemical Industry Co., Ltd. Filling amount: 70 g / batch
Kneading temperature: 190 ° C
Blade rotation speed: 40 rpm
Preheating time: 5 minutes Kneading time: 2 minutes

<Manufacturing of polyethylene resin composition for molding evaluation>
In the composition of the blending ratio shown in Example 1 of Table 1, 1,000 ppm of IRGANOX B225 manufactured by BASF Japan Ltd. and 500 ppm of calcium stearate manufactured by Tannan Chemical Industry Co., Ltd. were blended as additives, manufactured by Toshiba Machine Co., Ltd. Using TEM26SX (screw diameter: 26 mm, L / D = 64), pelletization was performed under the conditions of set temperature: 200 ° C., screw rotation speed: 200 rpm, and discharge rate: 15 kg / hr.
Table 1 shows the physical characteristics and evaluation results of the polyethylene resin composition. The obtained composition has good compatibility of each component, has excellent hollow moldability due to appropriate fluidity and high melt tension, has a long breaking time, has a high tensile impact strength, and has an appearance of a molded product. Was good.

[Examples 2 to 4]
The same procedure as in Example 1 was carried out except that the conditions were set so as to obtain the composition shown in Table 1.
In the production of the polyethylene component (A), except that the conditions for the amount of ethylene as the main raw material and the amount of hydrogen as the chain transfer agent were changed so as to be the polymer shown in Table 1, The polyethylene component (A) of Examples 2 to 4 was obtained in the same manner as in the production.
The evaluation results of the obtained polyethylene resin composition are shown in Table 1. The obtained polyethylene resin composition had good compatibility of each component, a long breaking time, high tensile impact strength, good hollow moldability, and a good appearance of the molded product.

[Comparative Example 1]
The same procedure as in Example 1 was carried out except that the conditions were set so as to obtain the composition shown in Table 1. However, in Comparative Example 1, the polyethylene component (A) did not contain the polyethylene components (B) and (C), and was produced by single-stage polymerization. The evaluation results of the obtained polyethylene resin composition are shown in Table 1. The obtained polyethylene resin composition had a short breaking time and insufficient tensile impact strength.

[Comparative Example 2]
The same procedure as in Example 1 was carried out except that the conditions were set so as to obtain the composition shown in Table 1.
In the production of the polyethylene component (A), except that the conditions for the amount of ethylene as the main raw material and the amount of hydrogen as the chain transfer agent were changed so as to be the polymer shown in Table 1, the above-mentioned polyethylene component (A) The polyethylene component (A) of Comparative Example 2 was obtained in the same manner as in the production.
The evaluation results of the obtained polyethylene resin composition are shown in Table 1. The obtained polyethylene resin composition had a short breaking time, a low tensile impact strength, poor hollow moldability, and a poor appearance of the molded product.

[Comparative Example 3]
The same procedure as in Example 1 was carried out except that the conditions were set so as to obtain the composition shown in Table 1.
In the production of the polyethylene component (A), except that the conditions for the amount of ethylene as the main raw material and the amount of hydrogen as the chain transfer agent were changed so as to be the polymer shown in Table 1, the above-mentioned polyethylene component (A) The polyethylene component (A) of Comparative Example 3 was obtained in the same manner as in the production.
The evaluation results of the obtained polyethylene resin composition are shown in Table 1. The obtained polyethylene resin composition had a short breaking time, a low tensile impact strength, poor hollow moldability, and a poor appearance of the molded product.

It can be seen that Examples 1 to 4 have a longer breaking time and a larger tensile impact strength than Comparative Examples 1 to 3. Further, it can be seen that Examples 1 to 4 are superior in hollow moldability and appearance of the molded product as compared with Comparative Examples 2 and 3.

According to the present invention, it is excellent in hollow moldability, environmental stress crack resistance, impact resistance, can be molded thinner and lighter, has a high crystallization rate, is excellent in high-speed moldability, and has a high molding cycle. It is possible to provide a polyethylene resin composition having good pinch-off characteristics, high compatibility of resin components, and particularly excellent appearance of the molded product, and a molded product made of the same.
Further, the polyethylene resin composition of the present invention is excellent in high fluidity during molding, and the molded product of the present invention is also excellent in odor, food safety, rigidity, heat resistance and the like.
Therefore, the polyethylene resin composition of the present invention and its molded product are suitable for applications such as containers that require such properties, and in particular, cosmetic containers, detergents, shampoo and rinse containers, edible oils, etc., which have excellent appearance. It can be suitably used for applications such as food containers.
Further, the container using the polyethylene resin composition of the present invention can be formed at high speed and has a high cycle, has excellent product characteristics, and is economically advantageous for cosmetic containers, detergents, shampoos, rinses, etc. Suitable as a container.
Further, since the polyethylene resin composition of the present invention has excellent performance as described above, it can be suitably used not only for the above containers but also for kerosene cans, chemical containers and the like that require such characteristics. Because it can be done, it is very useful industrially.

Claims (3)

The following polyethylene component (A) is contained in an amount of 10% by mass or more and 40% by mass or less, the following polyethylene component (D) is contained in an amount of 5% by mass or more and 50% by mass or less, and the following polyethylene component (E) is contained in an amount of 40% by mass or more and 85% by mass or less. A polyethylene resin composition that satisfies the following properties (1) to (8).
Polyethylene component (A); Characteristic (a1): Melt flow rate (HLMFR) at a temperature of 190 ° C. and a load of 21.6 kg is 0.2 g / 10 minutes or more and 5 g / 10 minutes or less, and characteristic (a2): density 0.915 g / cm ³ or more and 0.945 g / cm ³ or less, characteristic (a3): the following polyethylene component (B) and the following polyethylene component (C), (B): (C) = 5: 95 ~ Polyethylene containing in a ratio of 95: 5 (% by mass).
Polyethylene component (B); Characteristic (b1): Melt flow rate (HLMFR) at a temperature of 190 ° C. and a load of 21.6 kg is 0.2 g / 10 minutes or more and 2 g / 10 minutes or less, and characteristic (b2): density 0.900 g / cm ³ or more 0.950 g / cm ³ polyethylene satisfy the following.
Polyethylene component (C); Characteristic (c1): Melt flow rate (HLMFR) at a temperature of 190 ° C. and a load of 21.6 kg is 0.4 g / 10 minutes or more and 10 g / 10 minutes or less, and characteristic (c2): density 0.900 g / cm ³ or more 0.970 g / cm ³ polyethylene satisfy the following.
Polyethylene component (D); Characteristics (d1): Melt flow rate (HLMFR) at a temperature of 190 ° C. and a load of 21.6 kg is 4 g / 10 minutes or more and 7 g / 10 minutes or less , and characteristics (d2): density is 0. 945 g / cm ³ or more 0.965 g / cm ³ or less, the characteristics (d3): temperature 170 ° C., elongation strain rate 0.1: elongation viscosity measured at (in 1 / sec) eta (t) (unit: Polyethylene in which the variation point of extensional viscosity due to strain hardening is observed in both logarithmic plots of Pa · sec) and extension time t (unit: sec).
Polyethylene component (E); Characteristic (e1): Melt flow rate (MFR) at a temperature of 190 ° C. and a load of 2.16 kg is 10 g / 10 minutes or more and 200 g / 10 minutes or less, and characteristic (e2): density is 0. 960 g / cm ³ or more 0.980 g / cm ³ polyethylene satisfy the following.
Characteristic (1): MFR is 0.1 g / 10 minutes or more and 1 g / 10 minutes or less.
Characteristic (2): HLMFR is 10 g / 10 minutes or more and 50 g / 10 minutes or less.
Characteristic (3): The melt flow rate ratio (HLMFR / MFR), which is the ratio of HLMFR to MFR, is 50 or more and 140 or less.
Characteristics (4): density of 0.940 g / cm ³ or more 0.965 g / cm ³ or less.
Characteristic (5): Both extension viscosity η (t) (unit: Pa · second) and extension time t (unit: second) measured at a temperature of 170 ° C. and an extension strain rate of 0.1 (unit: 1 / sec). In the log-log plot, the variation point of the extensional viscosity due to strain hardening is observed.
Property (6): The rupture time (FNCT) at 80 ° C. and 3.7 MPa according to the full notch creep test is 285 hours or more.
Characteristic (7): The tensile impact strength is 233 kJ / m ² or more.
Characteristic (8): The melting tension is 40 mN or more. A molded product produced by using the polyethylene resin composition according to claim 1. A container prepared by using the polyethylene resin composition according to claim 1.

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