JP7051395B2 - Ethylene polymer and its molded product - Google Patents

Description

The present invention relates to an ethylene polymer and a molded product thereof.

Polyethylene powder is used as a raw material for a wide variety of products such as films, sheets, microporous membranes, fibers, foams and pipes. In particular, high molecular weight polyethylene powder is suitably used as a raw material for microporous membranes for separators and high-strength fibers for secondary batteries typified by lead-acid batteries and lithium-ion batteries. Reasons why high molecular weight polyethylene powder is used for these applications include, for example, excellent stretchability, high tensile strength, and high chemical stability.

Since the high molecular weight polyethylene powder generally has a high viscosity, it may be difficult to perform a molding process such as injection molding in a molten state of the polyethylene powder. Therefore, for example, a molding method such as a so-called solid phase stretching method in which high molecular weight polyethylene polymer particles are compressed at a temperature below the melting point and then stretched, or a gel-like fiber obtained by dissolving high molecular weight polyethylene in a solvent can be obtained. A gel spinning method for stretching at high magnification has been developed. It is known that the polyethylene fibers obtained by these molding methods have very high strength and elastic modulus, and also have very excellent impact resistance.

With respect to high-strength fibers formed from high-molecular-weight polyethylene powder, there is an increasing demand for higher workability and / or higher performance of mechanical properties. On the other hand, for example, in Patent Document 1, the high molecular weight, high crystallization, and control of the particle surface structure, particle size, and molecular weight distribution are performed to improve the processability of the ethylene polymer and the mechanical strength of the molded product. Polyethylene powder technology for solid phase stretching is disclosed. Further, for example, in Patent Document 2, a polymer molecular chain during polymerization and another polymer are used as a method for controlling the higher-order structure of polyethylene in order to obtain a polyethylene powder suitable for solid-phase stretching, particularly as a method for reducing entanglement in a polymer. A technique for suppressing interference with a molecular chain is disclosed.
Further, polyethylene is known as a substance having high water repellency, water resistance and antifouling property due to its low surface energy and low wettability (see, for example, Patent Document 3). On the other hand, when polyethylene is used as a film, from the viewpoint of printing, on the contrary, in order to improve the wettability of coating and ink and improve the ink transfer, mechanical, physicochemical and chemical surface modification technologies are used. It is being studied diligently. For example, in order to improve the adhesiveness of the coating agent for surface modification, a clean process that minimizes contamination of the polyethylene surface with foreign matter such as dust, dust, and adsorbed gas, and a treatment for cleaning the surface to be coated, etc. (See, for example, Patent Document 4).

International Publication No. 2008/013144 International Publication No. 2012/053261 JP-A-2015-48396 Japanese Unexamined Patent Publication No. 62-97673

However, in recent years, there has been a demand for the development of high-strength fibers in which productivity and functionality are added in addition to processability and mechanical properties. High-strength fibers obtained from polyethylene powder are used, for example, in ropes, fishing nets, fishing lines, golf course nets, leisure goods and the like. It is desired that these processed products not only have long-term durability in terms of mechanical strength, but also have no change in appearance in long-term outdoor use, that is, have high antifouling durability. In recent years, a large amount of yellow sand has been generated in China and Mongolia due to global warming and desertification. However, these become a factor that promotes deterioration and modification by adhering to polyethylene processed products having high antifouling properties and deteriorates fiber durability. Polyethylene and polyethylene molded products that suppress the adhesion of pollutants and have unprecedented high antifouling properties in terms of hygiene and durability are desired.

Therefore, an object of the present invention is to provide an ethylene polymer (for example, polyethylene powder) capable of suppressing the adhesion of fine particles such as yellow sand in the atmosphere and enhancing the antifouling property.

As a result of diligent research to solve the above-mentioned problems of the prior art, the present inventors have obtained the calorific value ΔH of the irreversible heat generating component obtained by the 1st scan measurement of the step scan type DSC, and the pressed disk. It is determined that the ethylene polymer (for example, polyethylene powder) in which the total content of Mg and Al elements by SEM-EDX analysis of the state sheet is controlled within a predetermined range suppresses the adhesion of fine particles such as yellow sand in the atmosphere. The finding led to the present invention.

That is, the present invention is as follows.
[1]
The calorific value ΔH of the irreversible heat generation component obtained by the 1st scan measurement of the step scan type DSC is 30 J / g or more and 80 J / g or less.
An ethylene polymer having a total content of Mg and Al elements of 1% by mass or less by SEM-EDX analysis of a disc-shaped sheet pressed under the conditions of (1) and (2) below.
(1) 3 g of an ethylene polymer is pressed by a press molding machine at a maximum temperature of 130 ° C. and an average pressure of 15 MPa for 10 minutes.
(2) The ethylene polymer pressed in (1) above is cooled at 25 ° C. for 10 minutes while maintaining an average pressure of 11 MPa.
[2]
The ethylene polymer according to [1], which has a viscosity average molecular weight of 1 million or more and 10 million or less.
[3]
The ethylene polymer according to [1] or [2], wherein the total content of Mg and Al elements by inductively coupled plasma mass spectrometry (ICP / MS) is 20 mass ppm or less.
[4]
The ethylene polymer according to any one of [1] to [3], which has an average particle size of 100 μm to 300 μm.
[5]
The molded product of the ethylene polymer according to any one of [1] to [4].
[6]
A stretched molded product containing the ethylene polymer according to any one of [1] to [4] and having a tensile strength of 2.0 GPa or more.

The ethylene polymer according to the present invention can suppress the adhesion of fine particles such as yellow sand in the atmosphere and can obtain a molded product having excellent antifouling properties.

Hereinafter, embodiments for carrying out the present invention (hereinafter referred to as “the present embodiment”) will be described in detail. The following embodiments are examples for explaining the present invention, and are not intended to limit the present invention to the following contents. The present invention can be appropriately modified and carried out within the scope of the gist thereof.

[Ethylene polymer]
The ethylene polymer of the present embodiment (hereinafter, also simply referred to as “powder” or “particle”) is
The calorific value ΔH of the irreversible heat generating component obtained by the 1st scan measurement of the step scan type DSC is 35 J / g or more and 80 J / g or less, and the SEM of the disc-shaped sheet pressed under the conditions of (1) and (2) below. -The total content of Mg and Al elements by EDX analysis is 1% by mass or less.
(1) 3 g of an ethylene polymer is pressed by a press molding machine at a maximum temperature of 130 ° C. and an average pressure of 15 MPa for 10 minutes.
(2) The ethylene polymer pressed in (1) above is cooled at 25 ° C. for 10 minutes while maintaining an average pressure of 11 MPa.
The ethylene polymer is not particularly limited, and examples thereof include an ethylene homopolymer and a copolymer of ethylene and another comonomer.

The ethylene homopolymer means a polymer in which 99.5 mol% or more of the repeating unit is composed of ethylene. Since the polyethylene powder is an ethylene homopolymer, it can be stretched in a high orientation, and there is a tendency to obtain a molded product or fiber having excellent tensile strength. In addition, since polyethylene powder is a copolymer with other comonomer, it tends to be possible to suppress side reactions during polymerization, improve the polymerization rate, and improve the creep characteristics of the obtained molded product and fiber. be.

Other comonomer is not limited to the following, and examples thereof include α-olefins and vinyl compounds. The α-olefin is not particularly limited, and examples thereof include α-olefins having 3 to 20 carbon atoms. More specifically, the α-olefin is not particularly limited, and examples thereof include propylene, 1-butene, and 4-methyl-1. -Pentene, 1-hexene, 1-octene, 1-nonen, 1-decene, 1-undecene, 1-dodecene, 1-tridecene, 1-tetradecene can be mentioned. Among these, propylene and 1-butene are preferable from the viewpoint of heat resistance and strength of the molded product represented by the membrane and fiber. One type of comonomer may be used alone, or two or more types may be used in combination.

The molar ratio of ethylene in the copolymer is preferably 50% or more and less than 99.5%, more preferably 80% or more and less than 99.2%, and 90% or more and less than 99% from the viewpoint of the tensile strength of the fiber. More preferred. When the ethylene polymer is a copolymer, the amount of other comonomer in the copolymer can be measured by, for example, NMR.

The ethylene polymer of the present embodiment may contain additives such as an antioxidant and a light-resistant stabilizer.

Antioxidants are not limited to the following, but are, for example, dibutylhydroxytoluene, pentaerythyl-tetrakis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate], octadecyl-3. -(3,5-di-t-butyl-4-hydroxyphenyl) propionate and other phenolic compounds can be mentioned. The content of the antioxidant is not particularly limited, but is preferably 5000 mass ppm or less, more preferably 4000 mass ppm or less, and further preferably 3000 mass ppm or less.

The light-resistant stabilizer is not limited to the following, and is, for example, 2- (5-methyl-2-hydroxyphenyl) benzotriazole, 2- (3-t-butyl-5-methyl-2-hydroxyphenyl)-. Phenyltriazole-based light-resistant stabilizers such as 5-chlorobenzotriazole; bis (2,2,6,6-tetramethyl-4-piperidin) sebacate, poly [{6- (1,1,3,3-tetramethylbutyl) ) Amino-1,3,5-triazine-2,4-diyl} {(2,2,6,6-tetramethyl-4-piperidyl) imino} hexamethylene {(2,2,6,6-tetramethyl) -4-piperidyl) imino}] and other hindered amine compounds can be mentioned. The content of the light-resistant stabilizer is not particularly limited, but is preferably 5000 mass ppm or less, more preferably 4000 mass ppm or less, and further preferably 3000 mass ppm or less.

The content of the additive in the ethylene polymer can be determined, for example, by extracting by soxley extraction using tetrahydrofuran (THF) for 6 hours, and separating and quantifying the extract by liquid chromatography.

[The amount of heat of the irreversible heat generation component ΔH]
The calorific value ΔH of the irreversible heat generating component of the ethylene polymer is 30 J / g or more, preferably 35 J / g or more, and more preferably 40 J / g or more. The calorific value ΔH of the irreversible heat generating component of the ethylene polymer is 80 J / g or less, preferably 75 J / g or less, and more preferably 70 J / g or less. The calorific value ΔH of the irreversible heat-generating component of the ethylene polymer of the present embodiment is the calorific value obtained by the step scan modulation method of the temperature-modulated differential scanning calorimeter (temperature-modulated DSC), and is described in Examples described later. It can be obtained by the method. Since crystallization and crystal melting occur in competition during the DSC temperature rise measurement, the heat flow derived from the formation / growth of microcrystals and melting is canceled by the conventional DSC measurement method, and the thermal behavior of the microcrystals is investigated. That is difficult. On the other hand, when the temperature-modulated DSC is used, it can be separated into a heat flow of irreversible components such as crystallization and reversible components such as crystal melting and glass transition, and it is possible to evaluate the thermal behavior of microcrystals. ..

When the calorific value ΔH of the irreversible heat generating component is 30 J / g or more, the adhesion of atmospheric fine particles to the surface of the ethylene polymer is suppressed, and the antifouling property is improved. The mechanism by which such an effect is invented is not clear, but the present inventors presume as follows. The calorific value ΔH of the irreversible heat generating component means the ease of recrystallization of the amorphous portion of the ethylene polymer during temperature rise. The abundance, molecular size and dispersed state of the polymerization catalyst-derived inorganic compound remaining in the ethylene polymer are considered to be the main factors for the recrystallization of the amorphous portion. The large amount of recrystallized part of the amorphous part of the ethylene polymer at the time of temperature rise, that is, the amount of irreversible exothermic component, means that the catalyst inorganic residue is not unevenly distributed as a huge inorganic compound aggregate in the ethylene polymer, and the amorphous part region. It is achieved by uniformly dispersing them throughout and acting like a crystal nucleating agent. A state in which the fine inorganic compound is embedded in a thin film such as a film or a fiber or a molded product having a reduced diameter is achieved, and the exposure of the inorganic compound to the surface of the molded product is suppressed. Therefore, it is presumed that the affinity with the atmospheric fine particles on the surface, that is, the dust collecting ability can be lowered and the antifouling property can be improved. Further, when the calorific value ΔH of the irreversible heat generating component becomes larger than 80 J / g, it means that the amount of the amorphous portion in the ethylene polymer increases. Therefore, the entangled portion existing in the amorphous portion also increases, which causes a decrease in processability such as stretching process.

The method for controlling the calorific value ΔH of the irreversible heat generating component within the above range is not particularly limited, and examples thereof include controlling the synthesis conditions of the catalyst used when polymerizing the ethylene polymer. Specifically, the polymer is not particularly limited, but for example, a polymerized polymer is subjected to a pretreatment in which defects are introduced in advance into the crystal lattice of the catalyst carrier so that the carrier of the supported catalyst is crushed at the time of polymerization and disintegrates into fine particles. It suffices to prepare a catalyst that supports the catalyst species inside the carrier so that the carrier can be separated by widening the carrier spacing due to the growth of the catalyst, and does not select a co-catalyst that aggregates and precipitates during polymerization to become a macromolecule.

[Total content of Mg and Al elements by SEM-EDX analysis of pressed disc-shaped sheet]
The total content of Mg and Al elements by SEM-EDX analysis of the pressed disc-shaped sheet of the ethylene polymer of the present embodiment is 1% by mass or less, preferably 0.85% by mass or less, and more. It is preferably 0.70% by mass or less, and the smaller the amount, the more preferable. The lower limit of the total content of the Mg and Al elements is, for example, 0% by mass. The total content of Mg and Al elements by SEM-EDX analysis of the pressed disc-shaped sheet of the ethylene polymer of the present embodiment can be determined by the method described in Examples described later.
When the total content of Mg and Al elements by SEM-EDX analysis of the press-processed disc-shaped sheet of ethylene polymer is within the above range, polar inorganic chemical substances present on the surface layer of various polyethylene molded products are present. Since the amount is reduced, the affinity with the atmospheric fine particles is lowered, and the dust collecting power on the surface of the molded body is suppressed. In addition, by reducing the physical unevenness of the surface of the molded body due to foreign matter on the surface layer and increasing the smoothness, it is possible to reduce factors such as atmospheric fine particles accumulating in the recesses on the surface of the molded body, which are the starting points of surface retention of adherent substances. Tend.
The method for controlling the total content of Mg and Al elements by SEM-EDX analysis of the pressed disc-shaped sheet of the ethylene polymer is not particularly limited, but is not particularly limited, and for example, a catalyst used when polymerizing the ethylene polymer. It is possible to control the synthesis condition of. Specifically, the present invention is not particularly limited, but for example, using a co-polymer having high activity and low Al content, which will be described later, or maintaining the inside of the process at 50 ° C. or higher by a centrifugation method step, during the centrifugation step. Efficiently remove polar inorganic compounds present on the surface of the ethylene polymer in various forms such as addition of steam gas in the above and the supply flow rate of the steam gas to the total flow rate of the discharged gas of 10.0 ppmV or more and 100.0 ppmV or less. Examples include a method of separation.

[Viscosity average molecular weight (Mv)]
The viscosity average molecular weight (Mv) of the ethylene polymer of the present embodiment is preferably 1 million or more and 10 million or less, more preferably 2 million or more and 9 million or less, and further preferably 3 million or more and 8 million or less. .. The viscosity average molecular weight (Mv) of the ethylene polymer of this embodiment can be measured by the method described in Examples described later.

The ethylene polymer of the present embodiment has a viscosity average molecular weight (Mv) of 1,000,000 or more, so that a molded product having excellent mechanical strength such as tensile strength can be obtained.

On the other hand, in the ethylene polymer of the present embodiment, when the viscosity average molecular weight (Mv) is 10 million or less, the polymer chains do not become too long and the entanglement between the polymer chains can be suppressed, so that the molding processability is maintained. .. For example, the disappearance of the interface between ethylene polymers in the dry molding process becomes stable, the residual interface between the ethylene polymers is suppressed during the compression process, and there is a tendency that defects in the subsequent molding process or surface roughness can be suppressed. Suppressing the deterioration of the surface layer shape is considered to suppress the adhesion and retention of atmospheric fine particles on the surface of the molded product.

The method for controlling the viscosity average molecular weight (Mv) within the above range is not particularly limited, and examples thereof include changing the temperature at which ethylene is polymerized. The higher the polymerization temperature, the lower the molecular weight tends to be, and the lower the polymerization temperature, the higher the molecular weight tends to be. Further, another method for setting the viscosity average molecular weight (Mv) to 10 million or less is not particularly limited, and examples thereof include adding a chain transfer agent such as hydrogen when polymerizing ethylene. By adding a chain transfer agent, the molecular weight of the produced ethylene polymer tends to be low even at the same polymerization temperature. Further, although not particularly limited, it can also be adjusted by adding, for example, a metal complex that consumes hydrogen existing in the polymerization system, as described in US Pat. No. 6,258,903. It is preferable to control the viscosity average molecular weight (Mv) of the ethylene polymer by combining the above methods.

[Total content of Mg and Al elements by inductively coupled plasma mass spectrometry (ICP / MS) in ethylene polymer]
The total content of Mg and Al elements by inductively coupled plasma mass spectrometry (ICP / MS) of the present embodiment is preferably 20% by mass or less, more preferably 15% by mass or less, still more preferable. Is 10 mass ppm or less, and the smaller the amount, the more preferable. The lower limit of the total content of the Mg and Al elements is, for example, 0 mass ppm. When the total content of Mg and Al elements by inductively coupled plasma mass spectrometry (ICP / MS) of the ethylene polymer is within the above range, the bleed-out of the inorganic compound to the surface is reduced and the affinity with the atmospheric fine particles is improved. It becomes a molded body that can be suppressed.
The method for controlling the total content of Mg and Al elements by inductively coupled plasma mass spectrometry (ICP / MS) of an ethylene polymer is not particularly limited, but for example, a cocatalyst having high activity and low Al content, which will be described later, may be used. Use, use an co-catalyst that does not require an excessive amount for activation for the organic metal complex that is the catalytic activity point, use a catalyst carrier that does not have a huge crystal structure, and the like. ..

[Average particle size]
The average particle size of the ethylene polymer of the present embodiment is preferably 100 μm or more and 300 μm or less, more preferably 120 μm or more and 280 μm or less, and further preferably 150 μm or more and 250 μm or less. The average particle size of the ethylene polymer of this embodiment can be measured by the method described in Examples described later.

Since the ethylene polymer of the present embodiment has an average particle size of 100 μm or more, the bulk density and fluidity of the ethylene polymer are sufficiently high, so that the ethylene polymer can be put into a hopper or the like and can be weighed from the hopper. Tends to be better. Further, the ethylene polymer of the present embodiment has an average particle size of 300 μm or less, so that the sheet surface smoothness at the time of forming a sintered sheet is maintained.

In the present embodiment, the average particle size of the ethylene polymer is not particularly limited, but can be controlled by, for example, the particle size of the catalyst used, and the larger the particle size of the catalyst, the larger the average particle size of the ethylene polymer. The smaller the particle size of the catalyst, the smaller the average particle size of the ethylene polymer tends to be obtained. Further, a method of controlling by adjusting the productivity of the ethylene polymer per unit catalyst amount can be mentioned.

[Catalyst component]
The catalyst component used for producing the ethylene polymer of the present embodiment is not particularly limited, and for example, it can be produced using a metallocene catalyst, a Ziegler-Natta catalyst, or the like. Among them, a metallocene catalyst capable of reducing low molecular weight components is preferably used.
As an example using a metallocene catalyst, a general transition metal compound is used. Such a metallocene catalyst is, for example, an organic aluminum compound (b), a transition metal compound (c) having a cyclic η-binding anion ligand, and the cyclic η-binding anion ligand in the carrier component (a). It can be obtained by carrying an activator (d) capable of forming a complex expressing catalytic activity by reacting with a transition metal compound having.

The transition metal compound having a cyclic η-binding anion ligand used in the present embodiment can be represented by, for example, the following formula 1.
L1 _j W _k M3X2 _p X3 _q ... (Equation 1)
In formula 1, each L1 is independently selected from the group consisting of a cyclopentadienyl group, an indenyl group, a tetrahydroindenyl group, a fluorenyl group, a tetrahydrofluorenyl group, and an octahydrofluorenyl group. Representing a cyclic anionic ligand, the ligand may have 1 to 8 substituents, each of which is independently a hydrocarbon group having 1 to 20 carbon atoms, a halogen atom, and carbon. Halogen-substituted hydrocarbon groups of 1 to 12, aminohydrocarbyl groups of 1 to 12 carbons, hydrocarbyloxy groups of 1 to 12 carbons, dihydrocarbylamino groups of 1 to 12 carbons, hydrocarbylphoss of 1 to 12 carbons. It is a substituent having up to 20 non-hydrogen atoms selected from the group consisting of a fino group, a silyl group, an aminosilyl group, a hydrocarbyloxysilyl group having 1 to 12 carbon atoms, and a halosilyl group.
In Equation 1, M3 is a transition metal selected from the group of transition metals belonging to Group 4 of the Periodic Table with a formal oxidation number of +2, +3 or +4, and is a transition metal bonded to at least one ligand L1 by η5. Represents metal.
In formula 1, W is a divalent substituent having up to 50 non-hydrogen atoms, which binds to L1 and M3 at a valence of 1 valence each, thereby cooperating with L1 and M3. Represents a divalent substituent that forms a metallocycle, and X2 is a divalent anionic σ-bonded ligand that independently binds to M3 and a divalent anionic σ-bonded ligand. Anionic σ bond with up to 60 non-hydrogen atoms selected from the group consisting of a divalent anionic σ-bonded ligand that binds to a position and L1 and M3 with a valence of 1 valence each. Represents a type ligand.
In formula 1, X2 represents a neutral Lewis base-coordinating compound, each independently having up to 40 non-hydrogen atoms, and X3 represents a neutral Lewis base-coordinating compound.
j is 1 or 2, but when j is 2, in some cases two ligands L1 are attached to each other via a divalent group having up to 20 non-hydrogen atoms, said 2 The valent groups are a hydrocarbaziyl group having 1 to 20 carbon atoms, a halohydrocarbaziyl group having 1 to 12 carbon atoms, a hydrocarbyleneoxy group having 1 to 12 carbon atoms, and a hydrocarbyleneamino group having 1 to 12 carbon atoms. , A silanediyl group, a halosilanediyl group, and a silyleneamino group.
k is 0 or 1 and p is 0, 1 or 2, where X2 is a monovalent anionic sigma-bonded ligand or a divalent anionic σ bonded to L1 and M3. When it is a bound ligand, p is an integer less than 1 or more than the formal oxidation number of M3, and when X2 is a divalent anionic σ-bonded ligand bound only to M3, p. Is an integer smaller than the formal oxidation number of M3 by (j + 1) or more, and q is 0, 1 or 2.
Examples of the ligand X2 in the compound of the above formula 1 are not particularly limited, but are, for example, halide, a hydrocarbon group having 1 to 60 carbon atoms, a hydrocarbyloxy group having 1 to 60 carbon atoms, and 1 to 60 carbon atoms. Examples thereof include a hydrocarbylamide group having 1 to 60 carbon atoms, a hydrocarbylsulfide group having 1 to 60 carbon atoms, a silyl group, and a composite group thereof.
Examples of the neutral Lewis base-coordinating compound X3 in the compound of the above formula 1 are not particularly limited, but for example, phosphine, ether, amine, olefin having 2 to 40 carbon atoms, diene having 1 to 40 carbon atoms, and the like. Examples thereof include divalent groups derived from these compounds.

式２において、Ｍは、チタン、ジルコニウム及びハフニウムからなる群より選ばれる遷移金属であって、形式酸化数が＋２、＋３又は＋４である遷移金属を表し、Ｒ³は、各々独立して、水素原子、炭素数１～８の炭化水素基、シリル基、ゲルミル基、シアノ基、ハロゲン原子及びこれらの複合基からなる群より選ばれる、２０個までの非水素原子を有する置換基を表し、但し、該置換基Ｒ³が炭素数１～８の炭化水素基、シリル基又はゲルミル基であるとき、場合によっては２つの隣接する置換基Ｒ³が互いに結合して２価の基を形成し、これにより該２つの隣接する該置換基Ｒ１３にそれぞれ結合するシクロペンタジエニル環の２つの炭素原子間の結合と共働して環を形成することができる。
式２において、Ｘ’’は、各々独立して、ハライド、炭素数１～２０の炭化水素基、炭素数１～１８のヒドロカルビルオキシ基、炭素数１～１８のヒドロカルビルアミノ基、シリル基、炭素数１～１８のヒドロカルビルアミド基、炭素数１～１８のヒドロカルビルフォスフィド基、炭素数１～１８のヒドロカルビルスルフィド基及びこれらの複合基からなる群より選ばれる、２０個までの非水素原子を有する置換基を表し、但し、場合によっては２つの置換基Ｘ’’が共働して炭素数４～３０の中性共役ジエン又は２価の基を形成することができる。
式２において、Ｙは、－Ｏ－、－Ｓ－、－ＮＲ＊－又は－ＰＲ＊－を表し、但し、Ｒ＊は、水素原子、炭素数１～１２の炭化水素基、炭素数１～８のヒドロカルビルオキシ基、シリル基、炭素数１～８のハロゲン化アルキル基、炭素数６～２０のハロゲン化アリール基、又はこれらの複合基を表す。
式２において、ＺはＳｉＲ＊２、ＣＲ＊２、ＳｉＲ＊２ＳｉＲ＊２、ＣＲ＊２ＣＲ＊２、ＣＲ＊＝ＣＲ＊、ＣＲ＊２ＳｉＲ＊２又はＧｅＲ＊２を表し、但し、Ｒ＊は上で定義した通りであり、ｎは１、２又は３である。 In the present embodiment, the transition metal compound having a cyclic η-binding anion ligand is preferably the transition metal compound represented by the above formula 1 (where j = 1). Preferred examples of the compound represented by the above formula 1 (however, j = 1) are not particularly limited, and examples thereof include the compound represented by the following formula 2.

In formula 2, M is a transition metal selected from the group consisting of titanium, zirconium and hafnium, and represents a transition metal having a formal oxidation number of +2, +3 or +4, and R ³ is independently hydrogen. Represents a substituent having up to 20 non-hydrogen atoms selected from the group consisting of an atom, a hydrocarbon group having 1 to 8 carbon atoms, a silyl group, a gelmil group, a cyano group, a halogen atom and a composite group thereof. When the substituent R ³ is a hydrocarbon group having 1 to 8 carbon atoms, a silyl group or a gelmil group, in some cases, two adjacent substituents R ³ are bonded to each other to form a divalent group. This allows the ring to be formed in cooperation with the bond between the two carbon atoms of the cyclopentadienyl ring bonded to the two adjacent substituents R13, respectively.
In formula 2, each of X'' is a halide, a hydrocarbon group having 1 to 20 carbon atoms, a hydrocarbyloxy group having 1 to 18 carbon atoms, a hydrocarbylamino group having 1 to 18 carbon atoms, a silyl group, and a carbon. It has up to 20 non-hydrogen atoms selected from the group consisting of a hydrocarbylamide group having 1 to 18 carbon atoms, a hydrocarbylphosfide group having 1 to 18 carbon atoms, a hydrocarbylvir sulfide group having 1 to 18 carbon atoms and a complex group thereof. It represents a substituent, provided that, in some cases, two substituents X'' can work together to form a neutral conjugated diene or divalent group with 4 to 30 carbon atoms.
In formula 2, Y represents -O-, -S-, -NR *-or -PR *-, where R * is a hydrogen atom, a hydrocarbon group having 1 to 12 carbon atoms, and 1 to 12 carbon atoms. It represents a hydrocarbyloxy group of 8, a silyl group, an alkyl halide group having 1 to 8 carbon atoms, an aryl halide group having 6 to 20 carbon atoms, or a composite group thereof.
In Equation 2, Z represents SiR * 2, CR * 2, SiR * 2SiR * 2, CR * 2CR * 2, CR * = CR *, CR * 2SiR * 2 or GeR * 2, where R * is above. As defined in, n is 1, 2 or 3.

The transition metal compound having a cyclic η-binding anion ligand used in the present embodiment is not particularly limited, and examples thereof include the following compounds.

The zirconium-based compound is not particularly limited, but specifically, for example, bis (methylcyclopentadienyl) zirconium dimethyl, bis (n-butylcyclopentadienyl) zirconium dimethyl, bis (indenyl) zirconium dimethyl, and bis. (1,3-dimethylcyclopentadienyl) zirconium dimethyl, (pentamethylcyclopentadienyl) (cyclopentadienyl) zirconium dimethyl, bis (cyclopentadienyl) zirconium dimethyl, bis (pentamethylcyclopentadienyl) Zirconium dimethyl, bis (fluorenyl) zirconium dimethyl, ethylenebis (indenyl) zirconium dimethyl, ethylenebis (4,5,6,7-tetrahydro-1-indenyl) zirconium dimethyl, ethylenebis (4-methyl-1-indenyl) zirconium Dimethyl, ethylenebis (5-methyl-1-indenyl) zirconium dimethyl, ethylenebis (6-methyl-1-indenyl) zirconium dimethyl, ethylenebis (7-methyl-1-indenyl) zirconium dimethyl, ethylenebis (5-methoxy) -1-indenyl) zirconium dimethyl, ethylenebis (2,3-dimethyl-1-indenyl) zirconium dimethyl, ethylenebis (4,7-dimethyl-1-indenyl) zirconium dimethyl, ethylenebis- (4,7-dimethoxy-) 1-indenyl) zirconium dimethyl, methylenebis (cyclopentadienyl) zirconium dimethyl, isopropylidene (cyclopentadienyl) zirconium dimethyl, isopropylidene (cyclopentadienyl-fluorenyl) zirconium dimethyl, silylenebis (cyclopentadienyl) zirconium dimethyl , Dimethylsilylene (cyclopentadienyl) zirconium dimethyl and the like.

The titanium-based compound is not particularly limited, but specifically, for example, [(Nt-butylamide) (tetramethyl-η5-cyclopentadienyl) -1,2-ethandyl] titanium dimethyl, [(N). -T-Buyramide) (Tetramethyl-η5-Cyclopentadienyl) Dimethylsilane] Titanium Dimethyl, [(N-Methylamide) (Tetramethyl-η5-Cyclopentadienyl) Dimethylsilane] Titanium Dimethyl, [(N-Phenyl) Amide) (tetramethyl-η5-cyclopentadienyl) dimethylsilane] titanium dimethyl, [(N-benzylamide) (tetramethyl-η5-cyclopentadienyl) dimethylsilane] titanium dimethyl, [(N-t-butyramide) ) (Η5-Cyclopentadienyl) -1,2-Ethandiyl] Titanium dimethyl, [(N-t-Butyramide) (η5-Cyclopentadienyl) dimethylsilane] Titanium dimethyl, [(N-Methylamide) (η5-) Cyclopentadienyl) -1,2-etandyl] titanium dimethyl, [(N-methylamide) (η5-cyclopentadienyl) dimethylsilane] titanium dimethyl, [(Nt-butylamide) (η5-indenyl) dimethylsilane ] Titanium dimethyl, [(N-benzylamide) (η5-indenyl) dimethylsilane] Titanium dimethyl and the like can be mentioned.

The nickel-based compound is not particularly limited, but specifically, for example, dibromobistriphenylphosphine nickel, dichlorobistriphenylphosphine nickel, dibromodiacetane nickel, dibromodibenzonitrile nickel, and dibromo (1,2-bisdiphenylphosphino). Etan) Nickel, Dibromo (1,3-bisdiphenylphosphinopropane) Nickel, Dibromo (1,1'-diphenylbisphosphinopherosen) Nickel, Dimethylbisdiphenylphosphine Nickel, Dimethyl (1,2-bisdiphenylphosphinoetan) ) Nickel, Methyl (1,2-bisdiphenylphosphinoetan) nickel tetrafluoroborate, (2-diphenylphosphino-1-phenylethyleneoxy) phenylpyridine nickel, dichlorobistriphenylphosphine palladium, dichlorodibenzonitrile palladium, dichlorodi Examples thereof include acetonitrile palladium, dichloro (1,2-bisdiphenylphosphinoetan) palladium, bistriphenylphosphine palladium bistetrafluoroborate, bis (2,2'-bipyridine) methyl iron tetrafluoroborate etherate and the like.

Specific examples of the transition metal compound having a cyclic η-binding anion ligand used in the present embodiment are not particularly limited, but for example, further, for example, the names of the zirconium-based compounds and titanium-based compounds listed above are ". The "dimethyl" part (this appears immediately after the part at the end of the name of each compound, that is, the part called "zyroxide" or "titanium", and is the name corresponding to the part of X4 in the above formula 2. ), "Dichlor", "dibrom", "diiodo", "diethyl", "dibutyl", "diphenyl", "dibenzyl", "2- (N, N-dimethylamino) benzyl", "2-buten-" 1,4-Diyl "," s-trans-η4-1,4-diphenyl-1,3-butadiene "," s-trans-η-4-3-methyl-1,3-pentadiene "," s-trans- η4-1,4-dibenzyl-1,3-butadiene "," s-trans-η4-2,4-hexadiene "," s-trans-η4-1,3-pentadiene "," s-trans-η4- 1,4-Ditrill-1,3-butadiene "," s-trans-η4-1,4-bis (trimethylsilyl) -1,3-butadiene "," s-cis-η4-1,4-diphenyl-1 " , 3-butadiene "," s-cis-η-4-3-methyl-1,3-pentadiene "," s-cis-η4-1,4-dibenzyl-1,3-butadiene "," s-cis-η4 " -2,4-Hexadiene "," s-cis-η4-1,3-pentadiene "," s-cis-η4-1,4-ditril-1,3-butadiene "," s-cis-η4-1 " , 4-Bis (trimethylsilyl) -1,3-butadiene ", and other compounds with names that can be replaced with arbitrary compounds are also mentioned.

The transition metal compound having a cyclic η-binding anion ligand used in the present embodiment can be synthesized by a generally known method. In this embodiment, these transition metal compounds may be used alone or in combination.

Next, an activator capable of forming a complex expressing catalytic activity by reacting with the transition metal compound used in the present embodiment (hereinafter, also simply referred to as “activator”) will be described.

The activator used in the present embodiment is not particularly limited, and examples thereof include compounds defined by the following formula 3.
[L2-H] ^{d +} [M5 _m Q _p ] ^{d -...} Equation 3
(In the formula, [L2-H] d + represents a proton-donating Bronsted acid, where L2 represents a neutral Lewis base, d is an integer of 1-7; [M5mQp] d- is compatible. Represents a sex non-coordinating anion, where M5 represents a metal or metalloid belonging to any of Group 5 to Group 15 of the Periodic Table, where Q is independently hydride, halide and carbon number, respectively. Selected from the group consisting of a dihydrocarbylamide group of 2 to 20, a hydrocarbyloxy group having 1 to 30 carbon atoms, a hydrocarbon group having 1 to 30 carbon atoms, and a substituted hydrocarbon group having 1 to 40 carbon atoms. So, the number of Qs that are halides is 1 or less, m is an integer of 1 to 7, p is an integer of 2 to 14, d is as defined above, and pm = d. be.)

The non-coordinating anion is not particularly limited, but specifically, for example, tetrakisphenyl volate, tri (p-tolyl) (phenyl) borate, tris (pentafluorophenyl) (phenyl) borate, tris (2,). 4-Dimethylphenyl) (Hydophenyl) Borate, Tris (3,5-dimethylphenyl) (Phenyl) Borate, Tris (3,5-Di-Trifluorimethylphenyl) (Phenyl) Borate, Tris (Pentafluorophenyl) (Cyclohexyl) ) Borate, Tris (pentafluorophenyl) (naphthyl) borate, Tetrakiss (pentafluorophenyl) borate, Triphenyl (hydroxyphenyl) borate, Diphenyl-di (hydroxyphenyl) borate, Triphenyl (2,4-dihydroxyphenyl) borate , Tri (p-tolyl) (hydroxyphenyl) borate, Tris (pentafluorophenyl) (hydroxyphenyl) borate, Tris (2,4-dimethylphenyl) (hydroxyphenyl) borate, Tris (3,5-dimethylphenyl) ( Hydroxyphenyl) borate, tris (3,5-di-trifluorimethylphenyl) (hydroxyphenyl) borate, tris (pentafluorophenyl) (2-hydroxyethyl) borate, tris (pentafluorophenyl) (4-hydroxybutyl) Borate, Tris (Pentafluorophenyl) (4-hydroxy-cyclohexyl) Borate, Tris (Pentafluorophenyl) (4- (4'-Hydroxyphenyl) Phenyl) Borate, Tris (Pentafluorophenyl) (6-Hydroxy-2- Naftil) Borate and the like.

Examples of other preferable non-coordinating anions include, but are not limited to, borate in which the hydroxy group of the above-exemplified borate is replaced with an NHR group. Here, R is preferably a methyl group, an ethyl group or a tert-butyl group.
The proton-imparting Bronsted acid is not particularly limited, but specifically, for example, triethylammonium, tripropylammonium, tri (n-butyl) ammonium, trimethylammonium, tributylammonium and tri (n-octyl). ) Trialkyl group-substituted ammonium cations such as ammonium; N, N-dimethylanilinium, N, N-diethylanilinium, N, N-2,4,6-pentamethylanilinium, N, N-dimethylbenzylanily N, N-dialkylanilinium cations such as nium; Dialkylammonium cations such as di- (i-propyl) ammonium and dicyclohexylammonium; triphenylphosphonium, tri (methylphenyl) phosphonium, tri (dimethylphenyl) phos Triarylphosphonium cations such as phonium; or dimethylsulfonium, diethylfluphonium, diphenylsulfonium and the like can be mentioned.

In the present embodiment, the activator components may be used alone or in combination.

In the present embodiment, it is preferable that these catalyst components are supported on a solid component and used as a supported catalyst. Such a solid component is not particularly limited, but specifically, a porous polymer material such as a copolymer of polyethylene, polypropylene or styrene divinylbenzene; silica, zirconia, titania, boron oxide, calcium oxide, and oxidation. Selected from inorganic solid materials of Group 2, 3, 4, 13 and 14 elements of the Periodic Table, such as zinc, barium oxide, vanadium pentoxide, chromium oxide and thorium oxide, and mixtures thereof; and their compound oxides. Included are at least one inorganic solid material.
A more preferred carrier material is SiO ₂ . The particle size of the carrier can be any value, but is generally in the range of 1 to 3000 μm, preferably 3 to 2000 μm, and more preferably 5 to 1000 μm.

Further, the SiO ₂ carrier may be pretreated before the catalyst supporting operation. Specifically, firing at a high temperature can be mentioned. It is a supported site capable of chemically bonding water molecules added to the SiOH site on SiO ₂ and organic substances in silica pores and SiOH on the outer surface by promoting condensation by baking and drying at high temperature for a short time. The SiOH group can be preferentially left only inside the silica pores. It is preferably 500 ° C. or higher and lower than 650 ° C. for 5.0 hours or more and less than 7.0 hours, more preferably 650 ° C. or higher and lower than 750 ° C. for 3.0 hours or more and less than 4.0 hours, and further preferably 750 ° C. or higher and lower than 800 ° C. Bake and dry in the range of 2.5 hours or more and less than 3.0 hours.

The catalyst used in this embodiment is not particularly limited, but for example, the carrier component (a) includes an organic aluminum compound (b), a transition metal compound having a cyclic η-binding anion ligand (c), and the cyclic η. It can be obtained by carrying an activator (d) capable of forming a complex exhibiting catalytic activity by reacting with a transition metal compound having a binding anion ligand. The method for supporting the component (a) to the component (d) is not particularly limited, but generally, for example, the component (a), the component (c) and the component (d) are each dissolved in an inert solvent. Method of dissolving, mixing with component (a), and then distilling off the solvent; after dissolving component (b), component (c) and component (d) in an inert solvent, concentrate this to the extent that no solid precipitates. Then, a method of adding the component (a) in an amount capable of retaining the entire amount of the concentrate in the particles; the component (a) and the component (d) are first supported on the component (a), and then the component (c). A method of sequentially supporting the component (a), the component (d), and the component (c) on the component (a) is exemplified. In particular, as a method of supporting the carrier component to promote the entry of the catalyst into the pores, the component (b), the component (d), and the component (c) are sequentially added to the component (a), and decant cleaning is performed for each addition. A carrier method or the like in which the above steps are repeated is preferable. By sequentially adding a single component, the entry of the catalyst component into the inside of the carrier pores can be promoted from the viewpoint of molecular size. Further, it is considered that the carrier disintegration due to the polymerization growth can be promoted because the catalyst component excessively present around the carrier can be removed and the support of the catalyst on the outer surface of the carrier can be suppressed. In the present embodiment, the component (c) and the component (d) are generally liquid or solid. In the present embodiment, the component (a), the component (c), and the component (d) may be diluted with an inert solvent when supported.

The inert solvent used for this purpose is not particularly limited, but specifically, for example, aliphatic hydrocarbons such as isobutane, pentane, hexane, heptane, octane, decane, dodecane, kerosene, cyclopentane, cyclohexane, and the like. Examples thereof include alicyclic hydrocarbons such as methylcyclopentane, aromatic hydrocarbons such as benzene, toluene and xylene, and mixtures thereof. The inert solvent is preferably used after removing impurities such as water, oxygen and sulfur by using a desiccant, an adsorbent and the like.

In the present embodiment, the component (b) is preferably 1 × 10 ^-5 to 1 × 10 ^-1 mol, more preferably 1 × 10 ^-4 to 5 × 10 ⁻ per 1 g of the component (a). ² mol, the component (c) is preferably 1 × 10 ^-7 to 1 × 10 ^-3 mol, more preferably 5 × 10 ^-7 to 5 × 10 ^-4 mol, and the component (d) is 1 × 10 ^-7 to It is preferably in the range of 1 × 10 ^-3 mol, more preferably 5 × 10 ^-7 to 5 × 10 ^-4 mol. The amount of each component used and the method of carrying it are determined by the activity, economy, powder characteristics, scale in the reactor and the like. The obtained supported geometrically constrained metallocene catalyst is washed with a decantation or filtration using an inert solvent for the purpose of removing organic aluminum compounds, borate compounds, and titanium compounds that are not supported on the carrier. You can also do it.

It is recommended that the series of operations such as melting, contacting, and cleaning be performed at a temperature in the range of −30 ° C. or higher and 150 ° C. or lower, which is selected for each unit operation. A more preferable range of such a temperature is 0 ° C. or higher and 100 ° C. or lower. The series of operations for obtaining the supported geometrically constrained metallocene catalyst is preferably carried out in a dry, inert atmosphere.

Further, in the present embodiment, in addition to the above four catalyst components, an organoaluminum compound can be used as a catalyst component, if necessary. The organoaluminum compound that can be used in the present embodiment is not particularly limited, but is, for example, a compound represented by the following formula 4.
AlR ¹⁶ _n X ⁵ _3-n (Equation 4)
(Here, R ¹⁶ is an alkyl group having 1 to 12 carbon atoms and an aryl group having 6 to 20 carbon atoms, X ⁵ is a halogen, hydrogen or alkoxyl group, and the alkyl group is linear, branched or branched. It is circular, and n is an integer of 1 to 3.)

Here, the organoaluminum compound may be a mixture of compounds represented by the above formula 4. The organic aluminum compound that can be used in the present embodiment is not particularly limited, but for example, in the above formula 4, R ¹⁶ is a methyl group, an ethyl group, a butyl group, an isobutyl group, a hexyl group, an octyl group, a decyl group, and the like. Examples thereof include a phenyl group, a trill group and the like, and examples of X ⁵ include, but are not limited to, a methoxy group, an ethoxy group, a butoxy group, a chlor and the like.

The organoaluminum compound that can be used in the present embodiment is not particularly limited, but specifically, for example, trimethylaluminum, triethylaluminum, tributylaluminum, triisobutylaluminum, trihexylaluminum, trioctylaluminum, and tridecylaluminum. Or the reaction products of these organoaluminums with alcohols such as methyl alcohol, ethyl alcohol, butyl alcohol, pentyl alcohol, hexyl alcohol, octyl alcohol, decyl alcohol, etc., such as dimethylmethoxyaluminum, diethylethoxyaluminum, dibutylbutoxyaluminum. And so on.

The polymerization method is not particularly limited, and examples thereof include a method of (co) polymerizing ethylene or a monomer containing ethylene by a suspension polymerization method or a gas phase polymerization method. Among these, the suspension polymerization method is preferable from the viewpoint of efficiently removing the heat of polymerization. In the suspension polymerization method, an inert hydrocarbon medium can be used as a medium, and the monomer α-olefin itself may be used as a solvent.

The inert hydrocarbon medium is not particularly limited, and is, for example, an aliphatic hydrocarbon such as propane, butane, isobutane, pentane, isopentane, hexane, heptane, octane, decane, dodecane, kerosene; cyclopentane, cyclohexane, methyl. Aliphatic hydrocarbons such as cyclopentane; aromatic hydrocarbons such as benzene, toluene and xylene; halogenated hydrocarbons such as ethylene chloride, chlorbenzene and dichloromethane; mixtures thereof.

The polymerization temperature is not particularly limited, but is preferably, for example, 30 ° C. or higher and 100 ° C. or lower, more preferably 35 ° C. or higher and 90 ° C. or lower, and further preferably 40 ° C. or higher and 80 ° C. or lower. When the polymerization temperature is 30 ° C. or higher, industrially efficient production tends to be possible. Further, when the polymerization temperature is 100 ° C. or lower, continuous stable operation tends to be possible.

The polymerization pressure is not particularly limited, but is preferably 0.1 MPa or more and 2.0 MPa or less, more preferably 0.1 MPa or more and 1.5 MPa or less, still more preferably, from the viewpoint of the average particle size of the ethylene polymer. Is 0.1 MPa or more and 1.0 MPa or less.

The polymerization reaction can be carried out by any of a batch method, a semi-continuous method, and a continuous method, but it is preferable to carry out the polymerization by a continuous method. By polymerizing in a continuous manner, ethylene gas, solvent, catalyst, etc. are continuously supplied into the polymerization system and continuously discharged together with the produced ethylene (co) polymer, thereby causing a rapid reaction of ethylene. It becomes possible to suppress a high temperature state, and the inside of the polymerization system tends to be more stable. Further, it is preferable that the ethylene gas, solvent, catalyst and the like before being supplied to the polymerization reactor are supplied at the same temperature as in the reactor in order to stabilize the inside of the system. When ethylene reacts in a uniform state in the system, it tends to be possible to suppress the formation of branches, double bonds, etc. in the polymer chain. Further, the surface deformation of the polyethylene powder due to the decomposition and cross-linking of the ethylene (co) polymer tends to be suppressed. Therefore, a continuous equation that tends to be more uniform in the polymerization system is preferable.

By adding hydrogen as a chain transfer agent in the polymerization system at an appropriate concentration, it tends to be possible to control the molecular weight in an appropriate range. By adding hydrogen to the polymerization system, in addition to controlling the molecular weight, there is a tendency that chain transfer of the catalyst can be promoted and polymerization growth can be suppressed. This tends to suppress the rapid growth of polymer chains and prevent the formation of distorted particles. The hydrogen mole fraction of the gas phase in the polymerization system is preferably 0 mol% or more and 3.0 mol% or less, and more preferably 0.5 mol% or more and 2.5 mol% or less with respect to the entire system. It is more preferably 9.0 mol% or more and 2.0 mol% or less.

Further, it is more preferable that hydrogen is brought into contact with the catalyst in advance and then added into the polymerization system from the catalyst introduction line. Immediately after the catalyst is introduced into the polymerization system, the concentration of the catalyst near the outlet of the introduction line is high, and the rapid reaction of ethylene increases the possibility of a partial high temperature state. Here, by contacting hydrogen with the catalyst before introducing it into the polymerization system, it becomes possible to suppress the initial activity of the catalyst, and the particles in the initial stage of the polymerization of the ethylene polymer which has become a high temperature state due to the rapid polymerization. There is a tendency to suppress changes in shape.

The solvent separation method can be performed by a decantation method, a centrifugal separation method, a filter filtration method, or the like, but a centrifugal separation method having good separation efficiency between the polyethylene powder and the solvent is more preferable. In addition to the inert gas in the centrifuge, steam can be supplied as catalyst deactivation. The amount of water vapor in the centrifuge is not particularly limited, but the supply flow rate is preferably 10 ppmV or more and 100 ppmV with respect to the total gas flow rate. The temperature inside the process of centrifugation is not particularly limited, but is preferably 50 ° C. or higher and 80 ° C. or lower, more preferably 55 ° C. or higher and 75 ° C. or lower, and further preferably 60 ° C. or higher and 70 ° C. or lower. The method for deactivating the catalyst used for synthesizing the ethylene polymer is not particularly limited, but it is preferably carried out in a process in which the ethylene polymer and the solvent coexist to some extent. By introducing a chemical to inactivate the catalyst in the centrifugation step of physically separating the metal and inorganic components contained in the ethylene polymer to the outside, the low molecular weight components remaining in the solvent are reduced and generally polar. The deactivating agent, which is a compound, and the remaining catalytic inorganic compound have an affinity with each other, and the separation from the ethylene polymer body tends to be efficient.

The catalytic deactivating agent is not particularly limited, and examples thereof include oxygen, water, alcohols, glycols, phenols, carbon monoxide, carbon dioxide, ethers, carbonyl compounds, and alkynes.

The drying temperature after separating the solvent is not particularly limited, but is preferably 60 ° C. or higher and 150 ° C. or lower, more preferably 70 ° C. or higher and 140 ° C. or lower, from the viewpoint of controlling the surface area of the ethylene polymer. It is more preferably 80 ° C. or higher and 130 ° C. or lower. When the drying temperature is 60 ° C. or higher, efficient drying tends to be possible. Further, when the drying temperature is 150 ° C. or lower, it tends to be possible to dry the ethylene polymer in a state where decomposition and cross-linking are suppressed, and the particles are not exposed to the ambient environment above the melting point of the ethylene polymer. Tends to be suppressed from partially melting. In addition, in order to prevent the particles of the ethylene polymer from colliding with each other while melting, especially the outer surface of the ethylene polymer, and being transferred while being fused, the average particles are generated by the generation of macromolecules. There is a tendency to suppress the increase in diameter.

[Molded product]
A molded product can be obtained by molding the ethylene polymer of the present embodiment (for example, polyethylene powder). The molded product is not particularly limited, but can be obtained by, for example, injection molding, extrusion molding, press molding, or the like, and even if it has a molecular weight that makes melt molding with polyethylene alone difficult, it can be gelled with a solvent or the like. It can be obtained by various general molding methods. The molded product is not particularly limited, and examples thereof include a film, a sheet, a microporous membrane for a battery separator, and a sintered filter.

[Use]
The ethylene polymer of the present embodiment may have good processability in solid phase stretching processing, and further, a molded processed product having physical and surface properties that can inhibit the adhesion and deposition of suspended fine particles in the atmosphere. It is a raw material that can be provided. Therefore, the ethylene polymer of the present embodiment can be suitably used, for example, as a raw material for fibers that require high strength and as a raw material for a battery separator that requires a uniform thin microporous membrane structure. In addition, there is a tendency to be able to maintain a longer-term appearance than before and to suppress resin deterioration and provide long-term physical property stability for these molded products due to their high antifouling properties.

The present embodiment will be described in more detail with reference to the following specific examples and comparative examples, but the present embodiment is not limited to the following examples and comparative examples as long as the gist of the present embodiment is not exceeded. Various physical properties and evaluations in Examples and Comparative Examples described later were measured and evaluated by the methods shown below.

(Physical characteristics 1) Calorie ΔH of irreversible heat generation component obtained by 1st scan measurement of step scan type DSC
As the measurement sample, an ethylene polymer powder stored at a constant temperature and humidity of 23 ° C. and a humidity of 60% after polymerization was used. Using DSC (DSC8500) manufactured by PerkinElmer, step scan measurement mode (sample weight: 8 mg, sample pan material: aluminum, measurement temperature: 50 to 200 ° C, temperature rise rate: 10 ° C / min, temperature rise step Width: 1 ° C., isothermal time: 2 minutes). An empty aluminum sample pan was also measured under the above conditions, and the temperature-heat flow curve was corrected using the data analysis application pyris. In the irreversible component of the corrected temperature-heat flow curve, the calorific value ΔH of the heat generation component due to recrystallization was calculated.

(Physical characteristics 2) Total content of Mg and Al elements by SEM-EDX analysis of pressed disc-shaped sheet Hitachi High Technology Co., Ltd. using a test piece (disc-shaped sheet) made by pressing an ethylene polymer as a sample. The amounts of Mg and Al elements on the surface of the test piece were measured using a tabletop electron microscope TM3030 and an energy dispersive X-ray analyzer (EDX) SwiftED3000 manufactured by OXFORD INSTRUMENTS. Specifically, 3 grams (g) of ethylene polymer is filled in a circular mold having a thickness of 1.5 mm and a diameter of 52 mm, pressed by a press molding machine at a maximum temperature of 130 ° C. and an average pressure of 15 MPa for 10 minutes, and then averaged. A circular press test piece (disc-shaped sheet) was obtained by cooling at 25 ° C. for 10 minutes while maintaining a pressure of 11 MPa. The obtained circular press test piece was observed at TM3030 normal mode, an acceleration voltage of 15 kV, and a magnification of 300 times, and the position was adjusted so that the entire surface of the test piece was on the observation screen. The image was captured using the observation condition Swift3000, and 30 arbitrary points were observed in the point mode of the point & ID observation mode (process time high sensitivity, collection time 30 seconds), and the mass concentration of the total content of Mg and Al elements (mass concentration). Weight%) was calculated.

(Physical characteristics 3) Viscosity average molecular weight (Mv)
Using the ethylene polymer as a sample, the viscosity average molecular weight (Mv) of the ethylene polymer was determined by the method shown below according to ISO1628-3 (2010). First, 20 mg of ethylene polymer (polyethylene powder) is weighed in the melting tube, the melting tube is replaced with nitrogen, and then 20 mL of decahydronaphthalene (2,6-di-t-butyl-4-methylphenol) is added at 1 g / L. The ethylene polymer (polyethylene powder) was dissolved by stirring at 150 ° C. for 2 hours. The solution was placed in a constant temperature bath at 135 ° C., and the drop time (ts) between the marked lines was measured using a Canon- _Fenceke type viscometer (manufactured by Shibata Kagaku Kikai Kogyo Co., Ltd .: product number -100). Similarly, for the sample in which the amount of ethylene polymer was changed to 10 mg, 5 mg, and 2 mg, the drop time ( _ts ) between the marked lines was measured in the same manner as described above. In addition, the fall time (t _b ) of only decahydronaphthalene without an ethylene polymer as a blank was measured. The reduced viscosity (η _sp / C) of the ethylene polymer obtained according to the following formula is plotted to obtain the concentration (C) (unit: g / dL) and the reduced viscosity (η _sp / C) of the ethylene polymer. A linear equation was derived, and the extreme viscosity ([η]) extrapolated to a concentration of 0 was obtained.
η _sp / C = (ts / _{t b} -1) /0.1: (Unit: dL / g)
Next, the viscosity average molecular weight (Mv) was calculated using the value of the limit viscosity [η] in the following formula.
Mv = (5.34 × 10 ⁴ ) × [η] ^1.49

(Physical properties 4) Total content of Mg and Al elements in inductively coupled plasma mass spectrometry (ICP-MS) Approximately 0.2 g of ethylene polymer is weighed in a Teflon® decomposition vessel and has high purity. After adding nitrate and pressure-decomposing with Milestone General's microwave decomposition equipment ETHOS-TC, pure water purified by Japan Millipore's ultrapure water production equipment with a total volume of 50 mL was used as the test solution. .. For the above test solution, Al and Mg in the ethylene polymer were quantified by an internal standard method using an inductively coupled plasma mass spectrometer (ICP-MS) X series 2 manufactured by Thermo Fisher Scientific.

(Physical properties 5) Average particle size The average particle size of the polyethylene polymer is 10 types of sieves specified in JIS Z8801 (opening: 710 μm, 500 μm, 425 μm, 355 μm, 300 μm, 212 μm, 150 μm, 106 μm, 75 μm, 53 μm). In an integral curve obtained by integrating the mass of the ethylene polymer (polyethylene powder) remaining on various sieves from the side with a small opening, which is obtained when 100 g of the ethylene polymer (polyethylene powder) is classified using the above. The particle diameter at which the integrated value has a mass of 50% was defined as the average particle diameter.

(Physical characteristics 6) An ethylene polymer having a tensile strength of 3 grams (g) of a solid-phase stretched molded product was pressed by a press molding machine at a maximum temperature of 126 ° C. and an average pressure of 11 MPa for 10 minutes (cooling was performed for 10 minutes while maintaining 11 MPa). It was carried out at 25 ° C.). The obtained press sheet was preheated at 140 ° C. and rolled at 130 ° C. with a roll rolling mill having a roll delivery speed of 1 m / min so as to have a draw ratio of 6 times. The sheet obtained by the rolling process is cut out and set in a tensile tester (Instron Corporation, INSTRON5564) so that the chuck distance is 15 mm, and twice in the same direction as roll rolling at 130 ° C. and a drawing speed of 30 mm / min. In the continuous stretching step of the above, a solid-phase stretched molded product having a stretching ratio of 200 times was obtained from a press sheet. The total draw ratio was determined by the mass per unit length of the film before and after stretching.
The tensile strength (breaking strength) was calculated from the stress and elongation at the breaking point when stretched under the conditions of a test temperature of 20 ° C. and a tensile speed of 50 mm / min using the above tensile tester.

(Evaluation 1) Evaluation of adhesion of fine particles in the atmosphere 20 grams (g) of ethylene polymer is heated by a press molding machine manufactured by Toyo Seiki in a mold with a thickness of 0.5 mm. Subsequently, the press was performed at 15 MPa for 10 minutes and then cooled and pressed at 25 ° C. for 10 minutes while maintaining 11 MPa. 200 under-sensing samplers AN (with all-weather shelter) were installed next to the Stevenson screen installed in the C area of Asahi Kasei Corporation Mizushima Plant. Prepare two units, use one as a reference, and prepare the sizing lower Yuasa particle filter MF40B on the filter paper plate, and sizing the press sheet prepared above for the other unit on the filter paper plate, and prepare the atmosphere such as yellow sand. It was operated for 7 days to collect fine particles. After operation, the weight of each plate was measured, and the weight difference before installation was measured. The relationship between the reference MF40B increased weight (ΔwR) and the ethylene polymer press sheet increased weight (ΔwP) was derived, and the weight ratio ΔwP / ΔwR was evaluated as antifouling performance according to the following evaluation criteria.

(Evaluation criteria)
⊚: ΔwP / ΔwR <1.1
◯: 1.1 ≦ ΔwP / ΔwR <1.5
×: 1.5 ≦ ΔwP / ΔwR

[Preparation Example 1] Solid catalyst component [A]
Spherical silica having an average particle diameter of 10 μm, a surface area of 800 m ² / g, and an intraparticle pore volume of 1.9 mL / g was calcined at 750 ° C. for 3 hours under a nitrogen atmosphere to vaporize carbides and dehydrate them. The amount of surface hydroxyl groups of the dehydrated silica was 1.4 mmol / g per 1 g of SiO ₂ . Under a nitrogen atmosphere, 40 g of this dehydrated silica was dispersed in 800 mL of hexane in an autoclave having a capacity of 1.8 L to obtain a slurry. While keeping the obtained slurry at 50 ° C. under stirring, 80 mL of a hexane solution of triethylaluminum (concentration 1 mol / L) was added, and then the mixture was stirred for 2 hours to react triethylaluminum with the surface hydroxyl group of silica to treat triethylaluminum. A component [a] containing silica and a supernatant liquid in which the surface hydroxyl group of the triethylaluminum-treated silica was capped with triethylaluminum was obtained. Then, the unreacted triethylaluminum in the supernatant was removed by removing the supernatant in the obtained reaction mixture by decantation. Then, an appropriate amount of hexane was added to obtain 880 mL of a hexane slurry of triethylaluminum-treated silica.

On the other hand, 200 mmol of [(Nt-butylamide) (tetramethyl-η5-cyclopentadienyl) dimethylsilane] titanium-1,3-pentadiene (hereinafter referred to as “titanium complex”) is added to Isopar E [Exxon Chemical. Trade name of hydrocarbon mixture manufactured by the same company (USA)] 1 mol / 1 mol of composition formula AlMg ₆ (C ₂ H ₅ ) ₃ (n-C ₄ H ₉ ) ₁₄ synthesized in advance from triethylaluminum and dibutylmagnesium by dissolving in 1000 mL. 20 mL of L-hexane solution was added, and hexane was further added to adjust the titanium complex concentration to 0.1 mol / L to obtain component [b].

Further, 5.7 g of bis (taroalkyl hydride) methylammonium-tris (pentafluorophenyl) (4-hydroxyphenyl) borate (hereinafter referred to as "borate") is added to 50 mL of toluene to dissolve the borate. A 100 mmol / L toluene solution was obtained. 5 mL of a 1 mol / L hexane solution of ethoxydiethylaluminum was added to this toluene solution of borate at room temperature, and hexane was further added to bring the borate concentration in the solution to 70 mmol / L. Then, the mixture was stirred at room temperature for 1 hour to obtain a reaction mixture [c] containing borate.

46 mL of this reaction mixture [c] containing borate was added to 880 mL of the slurry of the component [a] obtained above with stirring at 15 to 20 ° C., and borate was supported on silica. Then, the supernatant liquid in the obtained reaction mixture was removed by decantation once with toluene and three times with hexane to remove excess borate.

32 mL of the component [b] obtained above was added to the obtained silica slurry carrying borate, and the mixture was stirred for 3 hours to react the titanium complex with borate. Then, the supernatant liquid in the obtained reaction mixture was removed by decantation to obtain a supported metallocene catalyst [A] in which the catalytically active species was formed on the silica.

[Preparation Example 2] Solid catalyst component [B]
The solid catalyst component [B] was obtained by the same method as in Preparation Example 1 except that the silica firing conditions were changed at 600 ° C. for 5.5 hours.

[Preparation Example 3] Solid catalyst component [C]
Silica firing conditions were the same as in Preparation Example 1 except that the components [b] and [c] were simultaneously added to the slurry [a] at 600 ° C. for 5 hours, stirred for 3 hours, and then decanted. The solid catalyst component [C] was obtained by the method.

[Preparation Example 4] Solid catalyst component [D]
The solid catalyst component [D] was obtained by the same method as in Preparation Example 3 except that the silica firing condition was set to 600 ° C. for 10 hours.

[Preparation Example 5] Solid catalyst component [E]
The solid catalyst component [E] was obtained by the same method as in Preparation Example 3 except that aggregated silica having an average particle size of 30 μm was used.

[Preparation Example 6] Solid catalyst component [F]
Silica firing conditions were set at 600 ° C. for 5 hours, the component [b] was added to the slurry [a] and stirred for 3 hours, then decanted, then the component [c] was added and stirred for 1 hour, and then the supernatant was removed by decantation. The solid catalyst component [F] was obtained by the same method as in Preparation Example 1.

[Preparation Example 7] Solid catalyst component [G]
1,600 mL of hexane was added to a nitrogen-substituted 8 L stainless steel autoclave. With stirring at 10 ° C., 800 mL of 1 mol / L titanium tetrachloride hexane solution and 800 mL of hexane solution of the organic magnesium compound represented by 1 mol / L composition formula AlMg ₆ (C ₄ H ₉ ) ₁₂ (OSiBu ₂ Et) ₅ Was added simultaneously over 4 hours. After the addition, the temperature was slowly raised and the reaction was continued at 10 ° C. for 1 hour. After completion of the reaction, 1,600 mL of the supernatant was removed, and the solid catalyst component [G] was prepared by washing with 1,600 mL of hexane 10 times. The amount of titanium contained in 1 g of this solid catalyst component was 3.11 mmol.

[Example 1]
Hexane, ethylene and catalyst were continuously supplied to a Vessel-type 300L polymerization reactor equipped with a stirrer. The polymerization temperature was maintained at 75 ° C. by cooling the jacket. Hexane was supplied from the bottom of the polymerizer at 80 L / hour. The solid catalyst component [A] and triisobutylaluminum were used as co-catalysts. The solid catalyst component [A] is added from the middle of the liquid surface and the bottom of the polymer at a rate of 0.22 g / hour, and triisobutylaluminum is a solid catalyst from the middle of the liquid surface and the bottom of the polymer at a rate of 10 mmol / hour. It was added by an introduction line different from that of the component [A]. Ethylene was supplied from the bottom of the polymerizer to keep the polymerization pressure at 0.35 MPa. The production rate of polyethylene was 10 kg / hour. The polymerized slurry was continuously drawn into a flash drum at a pressure of 0.05 MPa and a temperature of 65 ° C. so that the level of the polymerization reactor was kept constant, and unreacted ethylene was separated. The polymerized slurry was continuously sent to a centrifuge so that the level of the flash drum was kept constant, and the polymer and other solvents and the like were separated. The temperature inside the centrifuge was 50 ° C., and the operating conditions of the water vapor amount in the feed gas including the inert nitrogen gas and the water vapor were maintained at 13 ppmV. The separated ethylene polymer was dried at 85 ° C. for 4 hours while blowing nitrogen to obtain ethylene polymer PE1.

The ethylene polymer PE1 obtained in Example 1 is subjected to (physical characteristics 1) calorific value ΔH of the irreversible heat generating component obtained by the 1st scan measurement of the step scan type DSC, and (physical characteristics 2) press processing according to the above-mentioned measurement method. Total content of Mg and Al elements by SEM-EDX measurement of the disk-shaped sheet, (physical characteristics 3) viscosity average molecular weight (Mv), (physical characteristics 4) induction-bonded plasma mass analysis (ICP / MS) in the ethylene polymer. The total content of Mg and Al elements, (physical characteristics 5) average particle size, (physical characteristics 6) tensile strength of the solid phase stretched molded product, and (evaluation 1) atmospheric fine particle adhesion amount were measured and evaluated. The results are shown in Table 1.

[Example 2]
The ethylene polymer PE2 was obtained by the same operation as in Example 1 except that the solid catalyst component [B] was used as the catalyst. Table 1 shows the physical characteristics of PE2 and the evaluation results.

[Example 3]
Using the solid catalyst component [C] as a catalyst, the ethylene polymer PE3 was obtained by the same operation as in Example 1 except that the temperature inside the centrifuge was set to 55 ° C. and the water vapor flow rate with respect to the total amount of discharged gas was set to 20 ppmV. rice field. Table 1 shows the physical characteristics of PE3 and the evaluation results.

[Example 4]
The ethylene polymer PE4 was obtained by the same operation as in Example 1 except that the solid catalyst component [C] was used as the catalyst. Table 1 shows the physical characteristics of PE4 and the evaluation results.

[Example 5]
Examples except that a solid catalyst component [C] is used as a catalyst, and an equivalent reaction product of 100 pm dicyclopentadienyl zirconium dichloride and trimethylaluminum is further added to the solid catalyst component [C] for polymerization. The ethylene polymer PE5 was obtained by the same operation as in 1. Table 1 shows the physical characteristics of PE5 and the evaluation results.

[Example 6]
The ethylene polymer PE6 was obtained by the same operation as in Example 1 except that the polymerization time was 3 kg / hour using the solid catalyst component [C] as a catalyst. Table 1 shows the physical characteristics of PE6 and the evaluation results.

[Example 7]
The ethylene polymer PE7 was obtained by the same operation as in Example 1 except that the solid catalyst component [E] was used as the catalyst. Table 1 shows the physical characteristics of PE7 and the evaluation results.

[Example 8]
The ethylene polymer was subjected to the same operation as in Example 1 except that the solid catalyst component [C] was used as a catalyst and the gas composition was changed so that the hydrogen gas gas phase concentration was 1.0 mol% in the polymerization system. PE8 was obtained. Table 1 shows the physical characteristics of PE8 and the evaluation results.

[Comparative Example 1]
As an alternative to the co-catalyst triisobutylaluminum, MMAO-3A / hex (modified methylarmoxane, Al concentration 5.7 mass% hexane solution MMAO) manufactured by Toso Finechem Co., Ltd. is adjusted to 200 equivalents of the solid catalyst component [C]. The ethylene polymer PE9 of Comparative Example 1 was obtained by the same operation as in Example 1 except that it was added. Table 1 shows the physical properties and evaluation results of the ethylene polymer PE9.

[Comparative Example 2]
The ethylene polymer PE10 was obtained by the same operation as in Example 1 except that the solid catalyst component [G] was used as the catalyst. Table 1 shows the physical characteristics of PE10 and the evaluation results.

[Comparative Example 3]
The ethylene polymer PE11 was obtained by the same operation as in Example 1 except that the solid catalyst component [D] was used as the catalyst. Table 1 shows the physical characteristics of PE11 and the evaluation results.

[Comparative Example 4]
Using the solid catalyst component [F] as a catalyst, the ethylene polymer PE12 was obtained by the same operation as in Example 1 except that the temperature inside the centrifuge was set to 50 ° C. and the water vapor flow rate with respect to the total amount of discharged gas was set to 8 ppmV. rice field. Table 1 shows the physical characteristics of PE12 and the evaluation results.

[Comparative Example 5]
An ethylene polymer PE12 was obtained by the same operation as in Example 1 except that the solid catalyst component [F] was used as a catalyst and the polymerization time was 3 kg / hour and the temperature inside the centrifuge was 45 ° C. Table 1 shows the physical characteristics of PE12 and the evaluation results.

From the above results, the ethylene polymer (for example, polyethylene powder) according to the present embodiment has a small amount of inorganic compounds on the surface layer of the molded product and is present in a dispersed state, so that adhesion of airborne fine particles such as yellow sand can be suppressed. I understand.

The ethylene polymer of the present embodiment may have good processability in solid phase stretching processing, and further, a molded processed product having physical and surface properties that can inhibit the adhesion and deposition of suspended fine particles in the atmosphere. It is a raw material that can be provided. Therefore, the ethylene polymer of the present embodiment can be suitably used, for example, as a raw material for fibers that require high strength and as a raw material for a battery separator that requires a uniform thin microporous membrane structure. The fibers obtained from the ethylene polymer of the present embodiment are, for example, high-performance textiles such as various sports clothing, bulletproof / protective clothing / protective gloves, and various safety equipment; various types of tag ropes / mooring ropes, yacht ropes, construction ropes, etc. Rope products; Various braided products such as fishing threads and blind cables; Net products such as fishing nets and ball-proof nets; Reinforcing materials such as chemical filters and battery separators; Curtain materials such as various non-woven fabrics and tents; For sports such as helmets and ski boards , For speaker cones, prepregs, etc., can be widely applied in industry, and provides long-term physical stability with suppressed resin deterioration and long-term appearance retention derived from high antifouling properties for these molded products. There is a possibility that it can be done.

Claims (6)

The calorific value ΔH of the irreversible heat generation component obtained by the 1st scan measurement of the step scan type DSC is 30 J / g or more and 80 J / g or less.
An ethylene polymer powder having a total content of Mg and Al elements of 1% by mass or less by SEM-EDX analysis of a disc-shaped sheet pressed under the conditions of (1) and (2) below.
(1) 3 g of an ethylene polymer is pressed by a press molding machine at a maximum temperature of 130 ° C. and an average pressure of 15 MPa for 10 minutes.
(2) The ethylene polymer pressed in (1) above is cooled at 25 ° C. for 10 minutes while maintaining an average pressure of 11 MPa. The ethylene polymer powder according to claim 1, which has a viscosity average molecular weight of 1 million or more and 10 million or less. The ethylene polymer powder according to claim 1 or 2, wherein the total content of Mg and Al elements by inductively coupled plasma mass spectrometry (ICP / MS) is 20 mass ppm or less. The ethylene polymer powder according to any one of claims 1 to 3, which has an average particle size of 100 μm to 300 μm. The molded product of the ethylene polymer powder according to any one of claims 1 to 4. A stretched molded product according to any one of claims 1 to 4, wherein the ethylene polymer powder has a tensile strength of 2.0 GPa or more.