JP2023138477A - Polyethylene powder and molded body made by using the powder - Google Patents

Abstract

To provide a polyethylene powder having excellent processability, excellent in production rate at the time of molding a molded body and capable of heightening a non-defective rate, physical homogeneity, or the like by suppressing strength degradation due to void defect or insufficient fusion, and to provide a molded body or the like produced by using the polyethylene powder.SOLUTION: Disclosed is a polyethylene powder in which a viscosity average molecular weight Mv is in a range of 100,000-10,000,000(g/mol); an average particle diameter X50 is in the range of 50-200 μm in a cumulative mass standard; the difference ΔMv (ΔMv=Mv75-Mv150) between Mv75(g/mol) of powders passing through a screen mesh having aperture of 75 μm and Mv150(g/mol) of powders remaining on the screen mesh having the aperture of 150 μm is more than 0(g/mol) but 4,000,000(g/mol) or less; and a ratio a/b of bulk density a(g/cm3) to tap density b(g/cm3) is 83.0(%) or more.SELECTED DRAWING: None

Description

The present invention relates to a polyethylene powder, a molded article using the same, and the like.

Ultra-high molecular weight polyethylene powder, which has a higher molecular weight than general-purpose polyethylene, has better wear resistance, impact resistance, self-lubricating properties, chemical resistance, low-temperature properties, dimensional stability, and light weight compared to other engineering plastics and metals. , excellent food safety, etc. Therefore, the molded products are used in various fields such as lining materials for ships and trucks, gears and bearings for machinery, rollers for food transportation, backing materials for skis, and artificial bones and joints.

Ultra-high molecular weight polyethylene has low melt fluidity due to its high molecular weight, making it difficult to melt and knead the resin. Therefore, the molding method is often press molding, ram extrusion molding, screw extrusion molding, etc. in which powdered raw material resin is heated and compressed as it is. Challenges in molding ultra-high molecular weight polyethylene include slow processing speed, poor productivity, poor powder filling, and insufficient fusion between powders, resulting in void defects and reduced strength, resulting in a low yield rate. In particular, the larger the molded body, the greater the difference in physical properties between the center and the ends of the molded body. These problems hinder the wider use of ultra-high molecular weight polyethylene molded articles.

Several methods are being considered to solve these problems. For example, Patent Document 1 reports that productivity can be improved by mixing low molecular weight polyethylene with a molecular weight of 5,000 to 20,000 to ultra-high molecular weight polyethylene with a molecular weight of 1 million or more.

Further, Patent Document 2 reports that processability can be improved by narrowing the molecular weight distribution using a special crosslinked metallocene catalyst system.

Further, Patent Document 3 reports that productivity during compression molding can be improved by narrowing the molecular weight distribution and particle size distribution.

Further, Patent Document 4 reports that by subjecting powder to special heat treatment, uniquely defined powder spreading parameters can be adjusted, the occurrence of void defects can be suppressed, and the yield rate can be improved.

Japanese Unexamined Patent Publication No. 57-177036 Special Publication No. 2009-514997 JP 2017-141312 Publication WO2020/171017 publication

According to the method described in Patent Document 1, an improvement in the production speed during molding is recognized, but at the same time, a problem arises in that the physical properties of the molded product, particularly the wear resistance, are greatly reduced. Furthermore, no consideration is given to improving the yield rate or variations in physical properties.

According to the method described in Patent Document 2, it is reported that processability can be improved by narrowing the molecular weight distribution. However, its effects have not been specifically demonstrated, and improvements in the yield rate and variations in physical properties have not been considered.

According to the method described in Patent Document 3, it is reported that processability is improved by narrowing the molecular weight distribution and particle size distribution. Although it is presumed to be effective in suppressing production speed and void defects, the effect has not been specifically shown, and improvement in the yield rate and variation in physical properties have not been taken into consideration.

According to the method described in Patent Document 4, it is reported that the occurrence of void defects can be suppressed and the rate of non-defective products can be improved. However, its performance is still not satisfactory for thicker and larger molded bodies. Furthermore, no consideration is given to improvements in production speed or variations in physical properties.

Therefore, in view of the above problems, the present invention has excellent processability, excellent production speed during molding of molded products, and suppresses decrease in strength due to void defects or insufficient fusion, thereby improving yield rate and uniformity of physical properties. It is an object of the present invention to provide a polyethylene powder that can improve the properties of polyethylene, etc., and a molded article using the same.

As a result of intensive research to solve the above problem, the present inventors surprisingly found that when polyethylene powder was classified using a screen mesh with a predetermined opening, it was found that powder with a large particle size and powder with a small particle size The inventors have discovered that polyethylene powder having a difference in viscosity average molecular weight and a predetermined ratio of bulk density to tap density can solve the above problems, and have completed the present invention. That is, the present invention is as follows.

[1]
having a viscosity average molecular weight Mv of 100,000 (g/mol) to 10,000,000 (g/mol),
having an average particle diameter _X50 of 50 μm to 200 μm on a cumulative mass basis,
The viscosity average molecular weight Mv ₇₅ (g/mol) of the pass powder when classified with a screen mesh with an opening of 75 μm and the viscosity average molecular weight Mv ₁₅₀ (g/mol) of the on-powder when classified with a screen mesh with an opening of 150 μm. The difference ΔMv (here, ΔMv = Mv ₇₅ - Mv ₁₅₀ ) is greater than 0 (g/mol) and less than or equal to 4,000,000 (g/mol),
The ratio a/b of the bulk density a (g/cm ³ ) to the tap density b (g/cm ³ ) is 83.0 (%) or more;
polyethylene powder.

[2]
The polyethylene powder according to [1], wherein the ratio a/b is greater than 88.0 (%).

[3]
The polyethylene powder according to [1] or [2], wherein the difference ΔMv is greater than 10 (g/mol) and less than 3,000,000 (g/mol).

[4]
A molded article obtained by molding a raw material containing the polyethylene powder according to any one of [1] to [3].

[5]
A press-molded body obtained by press-molding a raw material containing the polyethylene powder according to any one of [1] to [3].

[6]
An extruded product obtained by extruding a raw material containing the polyethylene powder according to any one of [1] to [3].
[7]
A microporous membrane using the polyethylene powder according to any one of [1] to [3].
[8]
A high-strength fiber using the polyethylene powder according to any one of [1] to [3].

According to the present invention, it has a unique difference in viscosity average molecular weight ΔMv and a unique ratio a/b of bulk density a and tap density b, and has excellent processability and excellent production speed when molding a molded body. It is possible to provide a polyethylene powder, a molded article using the same, and the like, which can improve the yield rate and uniformity of physical properties.

Hereinafter, an embodiment of the present invention (hereinafter referred to as "this embodiment") will be described in detail. Note that the following embodiments are illustrative for explaining the present invention, and the present invention is not limited thereto. That is, the present invention can be implemented with arbitrary changes within the scope without departing from the gist thereof. In this specification, when "~" is used to express numerical values or physical property values before and after it, it is used to include the values before and after it.

[Polyethylene powder]
The polyethylene powder of this embodiment (hereinafter also simply referred to as "powder") has a viscosity average molecular weight Mv of 100,000 (g/mol) to 10,000,000 (g/mol), based on cumulative mass. The viscosity average molecular weight Mv ₇₅ (g/mol) of pass powder has an average particle size X ₅₀ of 50 μm to 200 μm and is classified using a screen mesh with an opening of 75 μm. The difference ΔMv (here, ΔMv = Mv ₇₅ - Mv ₁₅₀ ) from the viscosity average molecular weight Mv ₁₅₀ (g/mol) of the on-powder is greater than 0 (g/mol) and 4,000,000 (g/mol). mol) or less, and the ratio a/b of the bulk density a (g/cm ³ ) to the tap density b (g/cm ³ ) is 83.0 (%) or more.

The polyethylene powder of this embodiment is a collection of polyethylene particles.

The polyethylene constituting the polyethylene powder of this embodiment is not limited to the following, but suitable examples include ethylene homopolymers, copolymers of ethylene and other comonomers, and the like. The copolymer may be a ternary random copolymer.

Other comonomers include, but are not particularly limited to, α-olefins, vinyl compounds, and the like.

The above α-olefin is not particularly limited, and examples thereof include α-olefins having 3 to 20 carbon atoms. Specifically, the α-olefin having 3 to 20 carbon atoms includes propylene, 1-butene, 4-methyl-1-pentene, 1-hexene, 1-octene, 1-nonene, 1-decene, 1-undecene. , 1-dodecene, 1-tridecene, 1-tetradecene and the like. Among these, propylene and 1-butene are preferred as the α-olefin from the viewpoint of impact resistance, abrasion resistance, heat resistance, and rigidity of the molded product of polyethylene powder.

The above-mentioned vinyl compound is not particularly limited, and examples thereof include vinylcyclohexane, styrene, and derivatives thereof.

Furthermore, if necessary, non-conjugated polyenes such as 1,5-hexadiene and 1,7-octadiene can also be used as other comonomers.

Other comonomers may be used alone or in combination of two or more.

The content of other comonomers is not particularly limited, and is preferably at most 0.8 mol%, more preferably at most 0.7 mol%, even more preferably at most 0.6 mol%, based on polyethylene. By adjusting the amount of other comonomers to 0.8 mol % or less, a molded article with excellent impact resistance, abrasion resistance, and rigidity tends to be easily obtained. When using other comonomers, the lower limit of the amount thereof is not particularly limited, and may be in excess of 0 mol% relative to polyethylene.

In addition, the content of the comonomer of polyethylene can be confirmed by the NMR method or infrared analysis method described in Examples below.

[Viscosity average molecular weight Mv]
The viscosity average molecular weight Mv (g/mol) of the polyethylene powder of this embodiment is 100,000 or more and 10,000,000 or less, preferably 500,000 or more and 9,000,000, and more preferably 1 ,000,000 or more and 8,000,000 or less.

When the viscosity average molecular weight Mv is 100,000 (g/mol) or more, the impact resistance and abrasion resistance of the molded article obtained by molding the polyethylene powder of this embodiment tend to be further improved. In addition, since the viscosity average molecular weight Mv is 10,000,0000 (g/mol) or less, melting of the powder and fusion between powders is promoted when molding the powder, and the production rate during the molding process is reduced. void defects due to insufficient fusion are further suppressed, and variations in physical properties within the molded article tend to be further reduced.

In addition, the viscosity average molecular weight Mv of the polyethylene powder can be adjusted by appropriately adjusting the polymerization conditions and the like using a catalyst described below. Specific examples of the polymerization conditions include allowing hydrogen to be present in the polymerization system and/or changing the polymerization temperature. Further, the viscosity average molecular weight Mv of the polyethylene powder can be determined by the method described in Examples below.

[Average particle diameter X ₅₀ ]
The average particle diameter X ₅₀ of the polyethylene powder of this embodiment is the particle diameter (sieve diameter) at which the cumulative mass is 50% by mass, that is, the median diameter. The average particle diameter _X50 of the polyethylene powder can be calculated by the method described in Examples below. The average particle diameter X ₅₀ of the polyethylene powder is 50 μm to 200 μm, preferably 60 μm to 175 μm, and more preferably 70 μm to 150 μm. When the average particle _diameter The variation in physical properties tends to be reduced. Further, when the average particle diameter _X50 of the polyethylene powder is 50 μm or more, scattering of the powder is suppressed, so that handling properties when handling the powder tend to be improved.

The average particle diameter _X50 of the polyethylene powder can be controlled by sieving through a screen mesh with a specific opening. In this embodiment, from the viewpoint of solubility in the solvent, it is particularly preferable to use polyethylene powder that has been passed through a screen mesh with an opening of 425 μm among standard sieves conforming to the JIS Z8801 standard.

[Difference ΔMv]
The difference ΔMv is the viscosity average molecular weight Mv ₇₅ of the powder that passed through the mesh when polyethylene powder was classified using a screen mesh with an opening of 75 μm (hereinafter also referred to as “pass powder”), and the viscosity average molecular weight Mv 75 of the powder that passed through the mesh when polyethylene powder was classified using a screen mesh with an opening of 150 μm. This is the difference from the viscosity average molecular weight Mv ₁₅₀ of the powder remaining on the mesh (hereinafter also referred to as "on-powder") when it is classified using the mesh. Specifically, the difference ΔMv is a value calculated based on the formula: ΔMv=Mv ₇₅ −Mv ₁₅₀ . The difference ΔMv is greater than 0 (g/mol) and less than or equal to 4,000,000 (g/mol), preferably greater than 5 (g/mol) and less than or equal to 3,500,000 (g/mol), More preferably, it is greater than 10 (g/mol) and less than 3,000,000 (g/mol). Since the difference ΔMv is larger than 0 (g/mol), the viscosity average molecular weight Mv of the large particle size powder is smaller than the viscosity average molecular weight Mv of the small particle size powder, and as a result, the large particle size powder has a slower heat transfer rate. Melting and fusion between powders progresses relatively easily, production speed during molding is further improved, void defects due to insufficient fusion are further suppressed, and variations in physical properties within the molded object tend to be further reduced. be. On the other hand, when the difference ΔMv is 4,000,000 (g/mol) or less, it is possible to prevent the viscosity average molecular weight Mv of the large particle size powder from becoming too low. As a result, the impact resistance and abrasion resistance of the molded article tend to be further improved. At the same time, it is possible to prevent the viscosity average molecular weight Mv of the small particle size powder from becoming too high, and as a result, the melting of the small particle size powder and the fusion between the powders progresses more easily, which increases the production speed during molding. There is a tendency that the void defects due to insufficient fusion are further suppressed, and the variation in physical properties within the molded article is further reduced.

The viscosity average molecular weight Mv ₇₅ and the viscosity average molecular weight Mv ₁₅₀ can be determined by the method described in Examples below, and the difference ΔMv can be calculated from these values based on the above formula.

A method for controlling the difference ΔMv to be greater than 0 (g/mol) and less than 4,000,000 (g/mol) is not particularly limited, but includes, for example, selecting a polymerization method. Specific examples include a method in which the polyethylene polymerization reaction is carried out in two stages using the catalyst described below (hereinafter also referred to as "two-stage polymerization"), and a method in which two stages are carried out in the first stage of two-stage polymerization. Examples include a method of polymerizing polyethylene having a lower molecular weight than the polymerization of the first stage.

The reason why the difference ΔMv can be controlled by the above method will be explained. In the first stage polymerization, low molecular weight polyethylene having a constant particle size distribution is produced. The large particle diameter powder after the first stage polymerization has a reduced catalytic activity and the ethylene diffusion rate to the catalyst in the center of the powder is slow, so the polymerization reaction does not occur during the second stage high molecular weight polyethylene polymerization. Difficult to progress. On the other hand, the catalyst activity of the small particle size powder after the first stage polymerization has not decreased as much as the relatively large particle size powder, and the ethylene diffusion rate to the catalyst in the center of the powder is relatively fast. The polymerization reaction progresses easily during the second stage of high molecular weight polyethylene polymerization. As a result, the viscosity average molecular weight Mv of the powder after the second stage polymerization can be increased as the particle size becomes smaller. Note that methods for controlling ΔMv within a predetermined range include adjusting the molecular weight in the first and second stages, adjusting the particle size distribution in the first stage, and the like.

Another method for controlling the difference ΔMv to be greater than 0 (g/mol) and less than 4,000,000 (g/mol) is to use a catalyst described below, use two polymerization vessels, and perform a parallel polymerization reaction. Examples include a method of mixing the obtained low molecular weight polyethylene with a large particle size and high molecular weight polyethylene with a small particle size using a polymerization method in which a polymerization slurry is then mixed (hereinafter also referred to as "parallel polymerization"). A method for controlling the particle size of the powder includes adjusting the activity of the catalyst, and specifically, changing the polymerization pressure and the amount of catalyst added.

Furthermore, another method for controlling the difference ΔMv to be greater than 0 (g/mol) and less than 4,000,000 (g/mol) is to dry blend multiple polyethylene powders with different particle sizes and viscosity average molecular weights Mv. An example is a method of mixing.

[Ratio a/b]
In this specification, bulk density a is the apparent density (g/cm ³ ) when polyethylene powder is allowed to fall freely, and tapped density b is the apparent density after tapping the free-falling powder 180 times. Means density (g/cm ³ ). The bulk density a and the tap density b can be determined by the method described in the Examples below, and from these values, the ratio a/b (% ) can be found. That is, the closer the ratio a/b is to 100 (%), the more densely packed the powder is in the free fall stage. The ratio a/b is 83.0 (%) or more, preferably greater than 86.0 (%), more preferably greater than 88.0 (%). The upper limit is not particularly limited, and may be 100(%) or less. When the ratio a/b is 83.0 (%) or more, the powders are easily packed densely and the powders are easily fused to each other, which suppresses the occurrence of void defects during molding and prevents the formation of defects within the molded object. The variation in physical properties tends to be further reduced.

Methods for controlling the ratio a/b to 83.0 (%) or higher are not particularly limited, but include, for example, devising the polymerization method, polymerization conditions, and powder cooling method.

First, specific examples of the polymerization method and polymerization conditions for controlling the ratio a/b to 83.0 (%) or more will be explained. Examples of the polymerization method include the above-mentioned two-stage polymerization or parallel polymerization. The polymerization conditions for two-stage polymerization are to allow the second-stage polymerization reaction to proceed rapidly, and the polymerization conditions for parallel polymerization are to use polyethylene with a large particle size in one polymerization vessel and to use polyethylene with a large particle size in the other polymerization vessel. An example of this is to polymerize small polyethylene and rapidly advance the polymerization reaction when polymerizing polyethylene with small particle size. Specific examples of polymerization conditions for rapidly advancing the polymerization reaction include adding a large amount of the co-catalyst described below and increasing the polymerization pressure. By producing polyethylene powder using this polymerization method and polymerization conditions, the surface irregularities of the powder particles become rougher as the particle size decreases, and this unique powder form allows for a higher ratio a/b than before. . By forming this unique powder form, the contact area between the large-particle powder with few surface irregularities and the small-particle powder with rough surface irregularities is reduced, and small particles fit into the gaps between the large-particle powder during the free-falling stage. The diameter powder is densely packed, and the value of the ratio a/b can be increased. Note that if the surface irregularities of both the large particle diameter powder and the small particle diameter powder are made rough, the surface irregularities of both will act as resistance and the value of the ratio a/b will become small.

The reason why the surface irregularities of the powder particles become rougher as the particle size decreases by the above method will be explained using the two-stage polymerization of the above specific example as an example. As mentioned above, the small particle size powder after the first stage polymerization is more likely to undergo the second stage polymerization reaction, that is, particle growth, compared to the large particle size powder, and the small particle size powder is more likely to undergo the second stage polymerization reaction, that is, particle growth. Since stress is difficult to disperse, cracks are more likely to occur on the powder surface than with large-particle powders, and as a result, as the particle size of the powder after two-stage polymerization becomes smaller, the surface irregularities of the powder particles become rougher.

Next, a powder cooling method will be described as a specific example for controlling the ratio a/b to 83.0 (%) or more. By rapidly cooling the powder while stirring the polymerized powder after drying, the surface irregularities of the powder particles can be made rougher as the particle size becomes smaller. This is because small particle diameter powders are easily cooled and stress due to volumetric contraction during cooling is difficult to disperse.

[Production method of polyethylene powder]
[Catalyst component]
The catalyst component used in the production of the polyethylene powder of this embodiment is not particularly limited, but includes, for example, a common Ziegler-Natta catalyst.

(Ziegler-Natta catalyst)
The Ziegler-Natta catalyst is a catalyst consisting of a solid catalyst component [A] and an organometallic compound component [B], where the solid catalyst component [A] is an inert hydrocarbon solvent represented by the following (Formula 1). A catalyst for olefin polymerization produced by reacting an organomagnesium compound (A-1) that is soluble in

(A-1): (M ¹ ) _α (Mg) _β (R ² ) _a (R ³ ) _b (Y ¹ ) _c ... (Formula 1)
(In formula 1, M ¹ is a metal atom belonging to Group 12, Group 13, and Group 14 of the periodic table, and R ² and R ³ are hydrocarbon groups having 2 to 20 carbon atoms. , Y ¹ is an alkoxy group, siloxy group, allyloxy group, amino group, amide group, -N=C-R ⁴ , R ⁵ , -SR ⁶ (where R ⁴ , R ⁵ and R ⁶ have 1 or more carbon atoms) Represents a hydrocarbon group of 20 or less. When c is 2, each Y ¹ may be different), β-keto acid residue, α, β, a, b, and c are real numbers that satisfy the following relationships: 0≦α, 0<β, 0≦a, 0≦b, 0≦c, 0<a+b, 0≦c/(α+β)≦2, nα+2β=a+b+c (where , n represents the valence of ^M1 ))

(A-2): Ti(OR ⁷ ) _d X ¹ _(4-d) ...(Formula 2)
(In Formula 2, d is a real number of 0 to 4, R ⁷ is a hydrocarbon group having 1 to 20 carbon atoms, and X ¹ is a halogen atom.)

The inert hydrocarbon solvent used in the reaction between the organomagnesium compound (A-1) and the titanium compound (A-2) is not particularly limited, but includes, for example, aliphatic hydrocarbons such as pentane, hexane, and heptane. ; aromatic hydrocarbons such as benzene and toluene; and alicyclic hydrocarbons such as cyclohexane and methylcyclohexane.

First, the organomagnesium compound (A-1) will be explained.
The organomagnesium compound (A-1) is indicated as a complex compound of organomagnesium soluble in an inert hydrocarbon solvent, and includes all dihydrocarbylmagnesium compounds and complexes of this compound with other metal compounds. It is something. The relational expression nα+2β=a+b+c of the symbols α, β, a, b, and c indicates the stoichiometry between the valence of the metal atom and the substituent.

In (Formula 1), the hydrocarbon group having 2 or more and 20 or less carbon atoms represented by R ² and R ³ is, for example, an alkyl group, a cycloalkyl group, or an aryl group, although it is not particularly limited. , ethyl group, propyl group, butyl group, pentyl group, hexyl group, octyl group, decyl group, cyclohexyl group, phenyl group and the like. Particularly preferred is an alkyl group. When α>0, metal atoms belonging to Group 12, Group 13, and Group 14 of the periodic table can be used as the metal atom M ¹ , such as zinc, boron, aluminum, and the like. Particularly preferred are aluminum and zinc.

The ratio β/α of magnesium to metal atom M ¹ is not particularly limited, but is preferably 0.1 or more and 30 or less, more preferably 0.5 or more and 10 or less. Further, when using a predetermined organomagnesium compound in which α=0, for example, when R ² is 1-methylpropyl, etc., it is soluble in an inert hydrocarbon solvent, and such a compound is also applicable to the present embodiment. give favorable results.

In the above (Formula 1), R ² and R ³ in the case of α=0 satisfy any one of the following three groups (1), group (2), and group (3). Recommended.
Group (1): At least one of R ² and R ³ is a secondary or tertiary alkyl group having 4 to 6 carbon atoms, preferably both R ² and R ³ have 4 to 6 carbon atoms. The following alkyl groups, at least one of which is a secondary or tertiary alkyl group.
Group (2): R ² and R ³ are alkyl groups having different numbers of carbon atoms, preferably R ² is an alkyl group having 2 or 3 carbon atoms, and R ³ is an alkyl group having 4 or more carbon atoms. be an alkyl group.
Group (3): At least one of R ² and R ³ is a hydrocarbon group having 6 or more carbon atoms, preferably an alkyl group whose total number of carbon atoms in R ² and R ³ is 12 or more. Something.

These groups will be specifically shown below.

In the above group (1), examples of the secondary or tertiary alkyl group having 4 to 6 carbon atoms include 1-methylpropyl group, 2-methylpropyl group, 1,1-dimethylethyl group, 2 -Methylbutyl group, 2-ethylpropyl group, 2,2-dimethylpropyl group, 2-methylpentyl group, 2-ethylbutyl group, 2,2-dimethylbutyl group, 2-methyl-2-ethylpropyl group, etc. . In particular, 1-methylpropyl group is preferred.

Further, examples of the alkyl group having 2 or 3 carbon atoms in the group (2) include ethyl group, 1-methylethyl group, propyl group, and the like. Among these, ethyl group is particularly preferred. Further, the alkyl group having 4 or more carbon atoms is not particularly limited, but specific examples thereof include a butyl group, a pentyl group, a hexyl group, a heptyl group, an octyl group, and the like. Particularly preferred are butyl group and hexyl group.

Further, in the above group (3), the hydrocarbon group having 6 or more carbon atoms is not particularly limited, but includes, for example, hexyl group, heptyl group, octyl group, nonyl group, decyl group, phenyl group, 2-naphthyl group, etc. can be mentioned. Among the hydrocarbon groups, alkyl groups are preferred, and among the alkyl groups, hexyl and octyl groups are particularly preferred.

Generally, as the number of carbon atoms contained in an alkyl group increases, it tends to become more soluble in an inert hydrocarbon solvent, and the viscosity of the solution tends to increase. Therefore, it is preferable to use an alkyl group with a moderately long chain in terms of handling. The above-mentioned organomagnesium compound can be used after being diluted with an inert hydrocarbon solvent, but the solution may contain or remain in trace amounts of Lewis basic compounds such as ethers, esters, and amines. can be used without any problem.

Next, ^Y1 will be explained.

In the above (Formula 1), Y ¹ is an alkoxy group, a siloxy group, an allyloxy group, an amino group, an amide group, -N=C-R ⁴ , R ⁵ , -SR ⁶ (where R ⁴ , R ⁵ and R ⁶ each independently represents a hydrocarbon group having 2 or more and 20 or less carbon atoms) or a β-keto acid residue.

In the above (Formula 1), the hydrocarbon group represented by R ⁴ , R ⁵ and R ⁶ is preferably an alkyl group or aryl group having 1 or more and 12 or less carbon atoms, and an alkyl group or aryl group having 3 or more and 10 or less carbon atoms. group is more preferred. Examples include, but are not limited to, methyl group, ethyl group, propyl group, 1-methylethyl group, butyl group, 1-methylpropyl group, 1,1-dimethylethyl group, pentyl group, hexyl group, 2-methylpentyl group , 2-ethylbutyl group, 2-ethylpentyl, 2-ethylhexyl, 2-ethyl-4-methylpentyl, 2-propylheptyl group, 2-ethyl-5-methyloctyl group, octyl group, nonyl group, decyl group, phenyl group, naphthyl group, etc. Particularly preferred are butyl group, 1-methylpropyl group, 2-methylpentyl group and 2-ethylhexyl group.

Further, in the above (Formula 1), Y ¹ is preferably an alkoxy group or a siloxy group.

Examples of the alkoxy group include, but are not limited to, a methoxy group, an ethoxy group, a propoxy group, a 1-methylethoxy group, a butoxy group, a 1-methylpropoxy group, a 1,1-dimethylethoxy group, a pentoxy group, a hexoxy group, 2-methylpentoxy group, 2-ethylbutoxy group, 2-ethylpentoxy group, 2-ethylhexoxy group, 2-ethyl-4-methylpentoxy group, 2-propylheptoxy group, 2-ethyl-5-methyl Preferred are octoxy, octoxy, phenoxy, and naphthoxy groups. Particularly preferred are butoxy group, 1-methylpropoxy group, 2-methylpentoxy group and 2-ethylhexoxy group.

The siloxy group is not particularly limited, but preferably includes, for example, a hydrodimethylsiloxy group, an ethylhydromethylsiloxy group, a diethylhydrosiloxy group, a trimethylsiloxy group, an ethyldimethylsiloxy group, a diethylmethylsiloxy group, a triethylsiloxy group, and the like. Particularly preferred are hydrodimethylsiloxy group, ethylhydromethylsiloxy group, diethylhydrosiloxy group, and trimethylsiloxy group.

There are no particular limitations on the method for synthesizing the organomagnesium compound (A-1), and for example, formula R ² MgX ¹ and formula R ² Mg (R ² has the above-mentioned meaning and X ¹ is a halogen atom). ) and an organomagnesium compound belonging to the group consisting of formulas M ¹ R ³ _n and M ¹ R ³ _(n-1) H (M ¹ and R ³ have the above-mentioned meanings, and n represents the valence of M ¹ ) is reacted with an organometallic compound belonging to the group consisting of the formula Y ¹ -H (Y ¹ is the aforementioned ) or by reacting an organomagnesium compound and/or an organoaluminium compound having a functional group represented by ^Y1 . Among these, when reacting an organomagnesium compound soluble in an inert hydrocarbon solvent with a compound represented by the formula Y ¹ -H, there is no particular restriction on the order of the reaction. Either a method of adding a compound represented by Y ¹ -H, a method of adding an organomagnesium compound to a compound represented by formula Y ¹ -H, or a method of adding both at the same time is used. be able to.

The molar composition ratio c/(α+β) of Y ¹ to all metal atoms in the organomagnesium compound (A-1) is preferably 0≦c/(α+β)≦2, and 0≦c/(α+β)< More preferably, it is 1. When the molar composition ratio of Y ¹ to all metal atoms is 2 or less, the reactivity of the organomagnesium compound (A-1) with respect to the titanium compound (A-2) tends to improve.

Next, the titanium compound (A-2) will be explained.

The titanium compound (A-2) is a titanium compound represented by the following formula 2.
(A-2): Ti(OR ⁷ ) _d X ¹ _(4-d) ...(Formula 2)
(In Formula 2, d is a real number of 0 to 4, R ⁷ is a hydrocarbon group having 1 to 20 carbon atoms, and X ¹ is a halogen atom.)

In the above (Formula 2), d is preferably 0 or more and 1 or less, and more preferably 0.

In addition, the hydrocarbon group represented by R ⁷ in the above (Formula 2) is not particularly limited, but includes, for example, a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, a 2-ethylhexyl group, Aliphatic hydrocarbon groups such as heptyl, octyl, decyl, and allyl groups; alicyclic hydrocarbon groups such as cyclohexyl, 2-methylcyclohexyl, and cyclopentyl; aromatic hydrocarbons such as phenyl and naphthyl groups Examples include groups. Particularly preferred are aliphatic hydrocarbon groups.

Examples of the halogen atom represented by X ¹ include a chlorine atom, a bromine atom, and an iodine atom. Particularly preferred is a chlorine atom. It is particularly preferable that the titanium compound (A-2) is titanium tetrachloride. In this embodiment, it is possible to use a mixture of two or more kinds of compounds selected from the above.

Next, the reaction between the organomagnesium compound (A-1) and the titanium compound (A-2) will be explained.

The reaction is preferably carried out in an inert hydrocarbon solvent, more preferably carried out in an aliphatic hydrocarbon solvent such as hexane or heptane. The molar ratio of the organomagnesium compound (A-1) and the titanium compound (A-2) in the reaction is not particularly limited, but the molar ratio of the titanium compound (A-2) to the Mg atoms contained in the organomagnesium compound (A-1) ) is preferably 0.1 or more and 10 or less, and more preferably 0.3 or more and 3 or less.

The reaction temperature is not particularly limited, but it is preferably carried out in a range of -80°C or more and 150°C or less, and more preferably carried out in a range of -40°C or more and 100°C or less.

There is no particular restriction on the order of addition of the organomagnesium compound (A-1) and the titanium compound (A-2). Either method of adding the organomagnesium compound (A-1) following A-2) or adding the organomagnesium compound (A-1) and the titanium compound (A-2) at the same time is possible; A method of adding the organomagnesium compound (A-1) and the titanium compound (A-2) at the same time is preferred. In this embodiment, the solid catalyst component [A] obtained by the above reaction is used as a slurry solution using an inert hydrocarbon solvent.

Another example of the Ziegler-Natta catalyst component used in the present embodiment includes a solid catalyst component [C] and an organometallic compound component [B], where the solid catalyst component [C] is represented by the following (Formula 3): A carrier (C -3), an organomagnesium compound (C-4) that is soluble in an inert hydrocarbon solvent represented by the following (formula 5), and a titanium compound (C-5) represented by the following (formula 6). An olefin polymerization catalyst produced by supporting and is preferable.

(C-1): (M ² ) _γ (Mg) _δ (R ⁸ ) _e (R ⁹ ) _f (OR ¹⁰ ) _g ... (Formula 3)
(In formula 3, M ² is a metal atom belonging to the group consisting of Groups 12, 13 and 14 of the periodic table, and R ⁸ , R ⁹ and R ¹⁰ each have a carbon number of 1 to 20 carbon atoms) It is a hydrogen group, and γ, δ, e, f, and g are real numbers that satisfy the following relationships: 0≦γ, 0<δ, 0≦e, 0≦f, 0≦g, 0<e+f, 0≦ g/(γ+δ)≦2, kγ+2δ=e+f+g (here, k represents the valence of ^M2 ))

(C-2): H _h SiCl _i R ¹¹ _(4-(h+i)) ...(Formula 4)
(In Formula 4, R ¹¹ is a hydrocarbon group having 1 to 12 carbon atoms, and h and i are real numbers that satisfy the following relationship: 0<h, 0<i, 0<h+i≦4)

(C-4): (M ¹ ) _α (Mg) _β (R ² ) _a (R ³ ) _b Y ¹ _c ... (Formula 5)
(In formula 5, M ¹ is a metal atom belonging to the group consisting of Groups 12, 13 and 14 of the periodic table, and R ² and R ³ are hydrocarbon groups having 2 or more and 20 or less carbon atoms. , Y ¹ is an alkoxy group, a siloxy group, an allyloxy group, an amino group, an amide group, -N=C-R ⁴ , R ⁵ , -SR ⁶ (where R ⁴ , R ⁵ and R ⁶ have 1 or more carbon atoms) Represents a hydrocarbon group of 20 or less. When c is 2, each Y ¹ may be different), β-keto acid residue, α, β, a, b, and c are real numbers that satisfy the following relationships: 0≦α, 0<β, 0≦a, 0≦b, 0≦c, 0<a+b, 0≦c/(α+β)≦2, nα+2β=a+b+c (where , n represents the valence of ^M1 ))

(C-5): Ti(OR ⁷ ) _d X ¹ _(4-d) ...(Formula 6)
(In formula 6, d is a real number of 0 to 4, R ⁷ is a hydrocarbon group having 1 to 20 carbon atoms, and X ¹ is a halogen atom.)

First, the organomagnesium compound (C-1) will be explained. The organomagnesium compound (C-1) is shown as a complex compound of organomagnesium soluble in an inert hydrocarbon solvent, but all dihydrocarbylmagnesium compounds and complexes of this compound with other metal compounds This includes: The relational expression kγ+2δ=e+f+g between the symbols γ, δ, e, f, and g in Formula 3 indicates the stoichiometry between the valence of the metal atom and the substituent.

In the above formula 3, the hydrocarbon group represented by R ⁸ to R ⁹ is not particularly limited, but is, for example, an alkyl group, a cycloalkyl group, or an aryl group, and specifically, a methyl group, an ethyl group, Examples include propyl group, butyl group, pentyl group, hexyl group, octyl group, decyl group, cyclohexyl group, phenyl group, and the like. Among these, preferably R ⁸ and R ⁹ are each an alkyl group. When α>0, metal atoms belonging to the group consisting of Groups 12, 13, and 14 of the periodic table can be used as the metal atom M ² , such as zinc, boron, aluminum, and the like. Particularly preferred are aluminum and zinc.

The ratio δ/γ of magnesium to metal atom M ² is not particularly limited, but is preferably 0.1 or more and 30 or less, more preferably 0.5 or more and 10 or less. Further, when using a predetermined organomagnesium compound in which γ=0, for example, when R ⁸ is 1-methylpropyl, etc., it is soluble in an inert hydrocarbon solvent, and such a compound is also used in this embodiment. give favorable results.

In the above (Formula 3), R ⁸ and R ⁹ in the case of γ = 0 are recommended to be any one of the following three groups (1), group (2), and group (3). Ru.
Group (1): At least one of R ⁸ and R ⁹ is a secondary or tertiary alkyl group having 4 to 6 carbon atoms, preferably both R ⁸ and R ⁹ have 4 to 6 carbon atoms. and at least one of them is a secondary or tertiary alkyl group.
Group (2): R ⁸ and R ⁹ are alkyl groups having different numbers of carbon atoms, preferably R ⁸ is an alkyl group having 2 or 3 carbon atoms, and R ⁹ is an alkyl group having 4 or more carbon atoms. To be.
Group (3): At least one of R ⁸ and R ⁹ is a hydrocarbon group having 6 or more carbon atoms, preferably an alkyl group in which the sum of the carbon numbers contained in R ⁸ and R ⁹ is 12 or more. .
These groups will be specifically shown below.

Examples of the secondary or tertiary alkyl group having 4 to 6 carbon atoms in group (1) include 1-methylpropyl group, 2-methylpropyl group, 1,1-dimethylethyl group, and 2-methylbutyl group. , 2-ethylpropyl group, 2,2-dimethylpropyl group, 2-methylpentyl group, 2-ethylbutyl group, 2,2-dimethylbutyl group, 2-methyl-2-ethylpropyl group, etc. are used. In particular, 1-methylpropyl group is preferred.

Further, examples of the alkyl group having 2 or 3 carbon atoms in group (2) include ethyl group, 1-methylethyl group, propyl group, and the like. Particularly preferred is ethyl group. Further, the alkyl group having 4 or more carbon atoms is not particularly limited, and examples thereof include butyl group, pentyl group, hexyl group, heptyl group, octyl group, and the like. Particularly preferred are butyl group and hexyl group.

Furthermore, the hydrocarbon group having 6 or more carbon atoms in group (3) is not particularly limited, but examples include hexyl group, heptyl group, octyl group, nonyl group, decyl group, phenyl group, 2-naphthyl group, etc. It will be done. Among the hydrocarbon groups, alkyl groups are preferred, and among the alkyl groups, hexyl and octyl groups are particularly preferred.

Generally, as the number of carbon atoms contained in an alkyl group increases, it tends to become more soluble in an inert hydrocarbon solvent, and the viscosity of the solution tends to increase. Therefore, it is preferable to use an alkyl group with a moderately long chain in terms of handling. Although the above-mentioned organomagnesium compound is used as an inert hydrocarbon solution, it can be used without any problem even if a trace amount of Lewis basic compounds such as ethers, esters, and amines are contained or remain in the solution.

Next, the alkoxy group (OR ¹⁰ ) in the above (Formula 3) will be explained.

The hydrocarbon group represented by R ¹⁰ is preferably an alkyl group or aryl group having 1 to 12 carbon atoms, particularly preferably an alkyl group or aryl group having 3 to 10 carbon atoms. R ¹⁰ is not particularly limited, but includes, for example, a methyl group, an ethyl group, a propyl group, a 1-methylethyl group, a butyl group, a 1-methylpropyl group, a 1,1-dimethylethyl group, a pentyl group, a hexyl group, 2-methylpentyl group, 2-ethylbutyl group, 2-ethylpentyl group, 2-ethylhexyl group, 2-ethyl-4-methylpentyl group, 2-propylheptyl group, 2-ethyl-5-methyloctyl group, octyl group , nonyl group, decyl group, phenyl group, naphthyl group, etc. Particularly preferred are butyl group, 1-methylpropyl group, 2-methylpentyl group and 2-ethylhexyl group.

The method of synthesizing the organomagnesium compound (C-1) is not particularly limited, but it is composed of the formula R ⁸ MgX ¹ and the formula R ⁸ Mg (R ⁸ has the above-mentioned meaning, and X ¹ is a halogen atom). and organometallic compounds belonging to the group consisting of the formula M ² R ⁹ _k and the formula M ² R ⁹ _(k-1) H (M ² , R ⁹ and k have the above-mentioned meanings). The reaction is carried out in an activated hydrocarbon solvent at a temperature of 25° C. or higher and 150° C. or lower, and if necessary, an alcohol or inorganic alcohol having a hydrocarbon group represented by R ⁹ (R ⁹ has the above-mentioned meaning) is added. A method of reacting with an alkoxymagnesium compound and/or an alkoxyaluminum compound having a hydrocarbon group represented by R ⁹ that is soluble in an activated hydrocarbon solvent is preferred.

Among these, when reacting an organomagnesium compound soluble in an inert hydrocarbon solvent with an alcohol, there is no particular restriction on the order of the reaction. Either a method of adding the compound or a method of adding both compounds at the same time can be used.

The reaction ratio between the organomagnesium compound soluble in an inert hydrocarbon solvent and the alcohol is not particularly limited, but the molar composition ratio g of alkoxy groups to all metal atoms in the alkoxy group-containing organomagnesium compound obtained as a result of the reaction. /(γ+δ) preferably satisfies 0≦g/(γ+δ)≦2, and more preferably 0≦g/(γ+δ)<1.

Next, the chlorinating agent (C-2) will be explained. The chlorinating agent (C-2) is a silicon chloride compound represented by the following (formula 4) and having at least one Si--H bond.

(C-2): H _h SiCl _i R ¹¹ _(4-(h+i)) ...(Formula 4)
(In Formula 4, R ¹¹ is a hydrocarbon group having 1 to 12 carbon atoms, and h and i are real numbers that satisfy the following relationship: 0<h, 0<i, 0<h+i≦4)

In the above (Formula 4), the hydrocarbon group represented by R ¹¹ is not particularly limited, but includes, for example, an aliphatic hydrocarbon group, an alicyclic hydrocarbon group, and an aromatic hydrocarbon group. , methyl group, ethyl group, propyl group, 1-methylethyl group, butyl group, pentyl group, hexyl group, octyl group, decyl group, cyclohexyl group, phenyl group and the like. Among these, alkyl groups having 1 to 10 carbon atoms are preferred, and alkyl groups having 1 to 3 carbon atoms such as methyl group, ethyl group, propyl group, and 1-methylethyl group are more preferred. Further, h and i are numbers larger than 0 that satisfy the relationship h+i≦4, and it is preferable that i is 2 or more and 3 or less.

These compounds include, but are not particularly limited to, HSiCl ₃ , HSiCl ₂ CH ₃ , HSiCl ₂ C ₂ H ₅ , HSiCl ₂ (C ₃ H ₇ ), HSiCl ₂ (2-C ₃ H ₇ ), HSiCl ₂ (C ₄ H ₉ ), HSiCl ₂ (C ₆ H ₅ ), HSiCl ₂ (4-Cl-C ₆ H ₄ ), HSiCl ₂ (CH=CH ₂ ), HSiCl ₂ (CH ₂ C ₆ H ₅ ), HSiCl ₂ (1-C ₁₀ H ₇ ), HSiCl ₂ (CH ₂ CH=CH ₂ ), H ₂ SiCl (CH ₃ ), H ₂ SiCl (C ₂ H ₅ ), HSiCl (CH ₃ ) ₂ , HSiCl (C ₂ H ₅ ) ₂ , HSiCl(CH ₃ )(2-C ₃ H ₇ ), HSiCl(CH ₃ )(C ₆ H ₅ ), HSiCl(C ₆ H ₅ ) ₂ and the like. A silicon chloride compound consisting of these compounds or a mixture of two or more selected from these compounds is used. Among these, HSiCl ₃ , HSiCl ₂ CH ₃ , HSiCl(CH ₃ ) ₂ and HSiCl ₂ (C ₃ H ₇ ) are preferred, and HSiCl ₃ and HSiCl ₂ CH ₃ are more preferred.

Next, the reaction between the organomagnesium compound (C-1) and the chlorinating agent (C-2) will be explained. During the reaction, the chlorinating agent (C-2) is mixed in advance with an inert hydrocarbon solvent, a chlorinated hydrocarbon such as 1,2-dichloroethane, o-dichlorobenzene, or dichloromethane; an ether medium such as diethyl ether or tetrahydrofuran. ; or a mixed medium thereof before use. Among these, inert hydrocarbon solvents are more preferred in terms of catalyst performance.

The reaction ratio of the organomagnesium compound (C-1) and the chlorinating agent (C-2) is not particularly limited, but the reaction ratio of the chlorinating agent (C-2) to 1 mol of magnesium atoms contained in the organomagnesium compound (C-1) ) is preferably 0.01 mol or more and 100 mol or less, more preferably 0.1 mol or more and 10 mol or less.

There are no particular restrictions on the reaction method of the organomagnesium compound (C-1) and the chlorinating agent (C-2), and the organomagnesium compound (C-1) and the chlorinating agent (C-2) can be reacted simultaneously in a reactor. A simultaneous addition method in which the chlorinating agent (C-2) is introduced into the reactor while reacting, a method in which the organomagnesium compound (C-1) is introduced into the reactor after the chlorinating agent (C-2) is introduced into the reactor, or Any method can be used in which the chlorinating agent (C-2) is introduced into the reactor after chlorinating agent (C-1) is charged into the reactor in advance. Among these, preferred is a method in which the chlorinating agent (C-2) is charged into the reactor in advance and then the organomagnesium compound (C-1) is introduced into the reactor. The carrier (C-3) obtained by the above reaction is preferably separated by filtration or decantation, and then thoroughly washed with an inert hydrocarbon solvent to remove unreacted substances or by-products. .

The reaction temperature between the organomagnesium compound (C-1) and the chlorinating agent (C-2) is not particularly limited, but is preferably 25°C or higher and 150°C or lower, and preferably 30°C or higher and 120°C or lower. The temperature is more preferably 40°C or higher and even more preferably 100°C or lower.

In the simultaneous addition method in which the organomagnesium compound (C-1) and the chlorinating agent (C-2) are simultaneously introduced into the reactor and reacted, the temperature of the reactor is adjusted to a predetermined temperature in advance, and the simultaneous addition is carried out by adjusting the temperature of the reactor to a predetermined temperature in advance. It is preferable to adjust the reaction temperature to a predetermined temperature by adjusting the temperature inside the reactor to a predetermined temperature during the reaction. In a method in which the organomagnesium compound (C-1) is introduced into the reactor after the chlorinating agent (C-2) is charged into the reactor in advance, the chlorinating agent (C-2) is charged into the reactor. It is preferable to adjust the reaction temperature to a predetermined temperature by adjusting the temperature to a predetermined temperature and adjusting the temperature inside the reactor to a predetermined temperature while introducing the organomagnesium compound into the reactor. In the method of introducing the chlorinating agent (C-2) into the reactor after charging the organomagnesium compound (C-1) into the reactor in advance, the temperature of the reactor containing the organomagnesium compound (C-1) It is preferable to adjust the reaction temperature to a predetermined temperature by adjusting the temperature inside the reactor to a predetermined temperature while introducing the chlorinating agent (C-2) into the reactor.

Next, the organomagnesium compound (C-4) will be explained. (C-4) is preferably represented by the above-mentioned (Formula 5).

(C-4): (M ¹ ) _α (Mg) _β (R ² ) _a (R ³ ) _b Y ¹ _c ... (Formula 5)
(In formula 5, M ¹ is a metal atom belonging to the group consisting of Groups 12, 13 and 14 of the periodic table, and R ² and R ³ are hydrocarbon groups having 2 or more and 20 or less carbon atoms. , Y ¹ is an alkoxy group, a siloxy group, an allyloxy group, an amino group, an amide group, -N=C-R ⁴ , R ⁵ , -SR ⁶ (where R ⁴ , R ⁵ and R ⁶ have 1 or more carbon atoms) Represents a hydrocarbon group of 20 or less. When c is 2, each Y ¹ may be different), β-keto acid residue, α, β, a, b, and c are real numbers that satisfy the following relationships: 0≦α, 0<β, 0≦a, 0≦b, 0<a+b, 0≦c/(α+β)≦2, nα+2β=a+b+c (where n is M Represents a valence of ¹ ))

The amount of the organomagnesium compound (C-4) to be used is a molar ratio of magnesium atoms contained in (C-4) to titanium atoms contained in the titanium compound (C-5) of 0.1 or more and 10 or less. It is preferably 0.5 or more and 5 or less.

The temperature of the reaction between the organomagnesium compound (C-4) and the titanium compound (C-5) is not particularly limited, but is preferably -80°C or more and 150°C or less, and in the range of -40°C or more and 100°C or less. It is more preferable that

The concentration of the organomagnesium compound (C-4) when used is not particularly limited, but it is preferably 0.1 mol/L or more and 2 mol/L or less based on the magnesium atoms contained in the organomagnesium compound (C-4). , more preferably 0.5 mol/L or more and 1.5 mol/L or less. Note that it is preferable to use an inert hydrocarbon solvent for diluting the organomagnesium compound (C-4).

There is no particular restriction on the order of addition of the organomagnesium compound (C-4) and the titanium compound (C-5) to the carrier (C-3), and the titanium compound (C-5) is added following (C-4). , adding the organomagnesium compound (C-4) following the titanium compound (C-5), or adding the organomagnesium compound (C-4) and the titanium compound (C-5) at the same time. It is. Among these, a method in which the organomagnesium compound (C-4) and the titanium compound (C-5) are added simultaneously is preferred. The reaction between the organomagnesium compound (C-4) and the titanium compound (C-5) is carried out in an inert hydrocarbon solvent, but it is preferable to use an aliphatic hydrocarbon solvent such as hexane or heptane. The catalyst thus obtained is used as a slurry solution with an inert hydrocarbon solvent.

Next, the titanium compound (C-5) will be explained. In this embodiment, (C-5) is a titanium compound represented by the above-mentioned (Formula 6).

(C-5): Ti(OR ⁷ ) _d X ¹ _(4-d) ...(Formula 6)
(In formula 6, d is a real number of 0 to 4, R ⁷ is a hydrocarbon group having 1 to 20 carbon atoms, and X ¹ is a halogen atom.)

In the above (Formula 6), the hydrocarbon group represented by R ⁷ is not particularly limited, but includes, for example, a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, a 2-ethylhexyl group, and a heptyl group. aliphatic hydrocarbon groups such as octyl, decyl, and allyl; alicyclic hydrocarbon groups such as cyclohexyl, 2-methylcyclohexyl, and cyclopentyl; aromatic hydrocarbon groups such as phenyl and naphthyl; etc. Among these, aliphatic hydrocarbon groups are preferred. The halogen atom represented by X ¹ is not particularly limited, but includes, for example, a chlorine atom, a bromine atom, and an iodine atom. Among these, a chlorine atom is preferred. The titanium compounds (C-5) selected from the above may be used alone or in combination of two or more.

The amount of the titanium compound (C-5) used is not particularly limited, but the molar ratio of the titanium atoms contained in the titanium compound (C-5) to the magnesium atoms contained in the carrier (C-3) is 0.01 or more. The following is preferable, and 0.05 or more and 10 or less are more preferable.

The reaction temperature of the titanium compound (C-5) is not particularly limited, but is preferably in the range of -80°C or more and 150°C or less, more preferably in the range of -40°C or more and 100°C or less.

In this embodiment, the method of supporting the titanium compound (C-5) on the carrier (C-3) is not particularly limited, and an excess of the titanium compound (C-5) on the carrier (C-3) is reacted. Although a method of supporting the titanium compound (C-5) efficiently by using a third component or a method of efficiently supporting the titanium compound (C-5) by using a third component may be used, A method of supporting by reaction is preferred.

Next, the organometallic compound component [B] used in this embodiment will be explained. The solid catalyst component used in this embodiment becomes a highly active polymerization catalyst when combined with the organometallic compound component [B]. The organometallic compound component [B] is sometimes called a "co-catalyst". The organometallic compound component [B] is preferably a compound containing a metal belonging to Group 1, Group 2, Group 12, and Group 13 of the periodic table, and in particular, an organoaluminum compound and/or Or an organic magnesium compound is preferable.

As the organoaluminum compound used as the organometallic compound component [B], it is preferable to use compounds represented by the following (Formula 7) alone or in combination.

AlR ¹² _j Z ¹ _(3-j) ...(Formula 7)

(In formula 7, R ¹² is a hydrocarbon group having 1 to 20 carbon atoms, Z ¹ is a group belonging to the group consisting of hydrogen atom, halogen atom, alkoxy group, allyloxy group, and siloxy group, and j is 2 to 3 (The number is as follows.)

In the above (Formula 7), the hydrocarbon group having 1 to 20 carbon atoms represented by R ¹² is not particularly limited, but includes, for example, an aliphatic hydrocarbon group, an aromatic hydrocarbon group, an alicyclic hydrocarbon group. This includes: Specific examples of organoaluminum compounds include trimethylaluminum, triethylaluminum, tripropylaluminum, tributylaluminum, tri(2-methylpropyl)aluminum (or triisobutylaluminum), tripentylaluminum, tri(3-methylbutyl)aluminum, Trialkylaluminum such as trihexylaluminum, trioctylaluminum, tridecylaluminum, etc., aluminum halide compounds such as diethylaluminum chloride, ethylaluminum dichloride, bis(2-methylpropyl)aluminum chloride, ethylaluminum sesquichloride, diethylaluminum bromide, Preferred are alkoxyaluminum compounds such as diethylaluminum ethoxide and bis(2-methylpropyl)aluminum butoxide, siloxyaluminum compounds such as dimethylhydrosiloxyaluminum dimethyl, ethylmethylhydrosiloxyaluminum diethyl, ethyldimethylsiloxyaluminum diethyl, and mixtures thereof. Particularly preferred are trialkyl aluminum compounds.

The organomagnesium compound used as the organometallic compound component [B] is preferably an organomagnesium compound represented by the above-mentioned formula (3) that is soluble in an inert hydrocarbon solvent.
(M ² ) _γ (Mg) _δ (R ⁸ ) _e (R ⁹ ) _f (OR ¹⁰ ) _g ... (Formula 3)
(In formula 3, M ² is a metal atom belonging to the group consisting of Groups 12, 13 and 14 of the periodic table, and R ⁸ , R ⁹ and R ¹⁰ each have a carbon number of 1 to 20 carbon atoms) It is a hydrogen group, and γ, δ, e, f, and g are real numbers that satisfy the following relationships: 0≦γ, 0<δ, 0≦e, 0≦f, 0≦g, 0<e+f, 0≦ g/(γ+δ)≦2, kγ+2δ=e+f+g (here, k represents the valence of ^M2 ))

This organomagnesium compound is shown as a complex compound of organomagnesium soluble in an inert hydrocarbon solvent, but it does not include all dialkylmagnesium compounds and complexes of this compound with other metal compounds. be. γ, δ, e, f, g, M ² , R ⁸ , R ⁹ , and OR ¹⁰ are as described above, but it is preferable that this organomagnesium compound has high solubility in an inert hydrocarbon solvent. δ/γ is preferably in the range of 0.5 or more and 10 or less, and compounds in which M ² is aluminum are more preferred.

Note that the combination ratio of the solid catalyst component and the organometallic compound component [B] is not particularly limited, but it is preferable that the organometallic compound component [B] is 1 mmol or more and 3,000 mmol or less per 1 g of the solid catalyst component.

[Polymerization conditions]
In the production of the polyethylene powder of this embodiment, the polymerization method is not particularly limited, but from the viewpoint of efficiently removing polymerization heat, a slurry polymerization method is used, and ethylene alone or a monomer containing ethylene (co-) is used. Polymerization is preferred. Furthermore, it is preferable to use multistage polymerization in which the polymerization is divided into two or more stages with different reaction conditions, or parallel polymerization in which the polymerization is performed in two or more reactors with different reaction conditions and mixed.

In the slurry polymerization method, an inert hydrocarbon medium can be used as the medium.

The inert hydrocarbon medium is not particularly limited, but includes, for example, aliphatic hydrocarbons such as propane, butane, isobutane, pentane, isopentane, hexane, heptane, octane, decane, dodecane, kerosene; cyclopentane, cyclohexane, methyl Examples include alicyclic hydrocarbons such as cyclopentane; aromatic hydrocarbons such as benzene, toluene, and xylene; halogenated hydrocarbons such as ethyl chloride, chlorobenzene, and dichloromethane; and mixtures thereof.

In the polymerization process of polyethylene powder, it is preferable to use an inert hydrocarbon medium having 6 or more and 10 or less carbon atoms. When the number of carbon atoms is 6 or more, low molecular weight components generated due to side reactions during ethylene polymerization or deterioration of polyethylene are relatively easily dissolved, and can be easily removed in the step of separating polyethylene and the polymerization medium. When the number of carbon atoms is 10 or less, adhesion of polyethylene powder to the reaction tank is suppressed, and industrially stable operation tends to be possible.

The polymerization reaction can be carried out in a batch, semi-continuous or continuous manner, but it is preferable to carry out the polymerization in a continuous manner.

By continuously supplying ethylene gas, solvent, catalyst, etc. into the polymerization system and continuously discharging it together with the produced polyethylene, it is possible to suppress the local high temperature state caused by the sudden reaction of ethylene, and the polymerization The system becomes more stable. When ethylene reacts while the system is homogeneous, the formation of branches and double bonds in the polymer chain is suppressed, making it difficult for polyethylene to lower its molecular weight and crosslink. Unmelted substances remaining during melting or dissolution are reduced, coloration is suppressed, and problems such as deterioration of mechanical properties are less likely to occur. Therefore, a continuous type is preferable because it makes the inside of the polymerization system more uniform.

The polymerization temperature is usually 30°C or more and 100°C or less, preferably 35°C or more and 95°C or less, and more preferably 40°C or more and 90°C or less. When the polymerization temperature is 30° C. or higher, industrially efficient production tends to be possible. When the polymerization temperature is 100° C. or lower, continuous and stable production tends to be possible.

The polymerization pressure is usually at least normal pressure and at most 5.0 MPa, preferably at least 0.1 MPa and at most 4.0 MPa, and more preferably at least 0.1 MPa and at most 3.0 MPa.

In the polymerization of polyethylene powder of this embodiment, when using continuous two-stage polymerization in which two polymerization reactions with different reaction conditions are performed consecutively, polyethylene with a lower molecular weight is polymerized in the first stage polymerization than in the second stage. It is preferable. The molecular weight of polyethylene can be controlled, for example, by introducing hydrogen into the polymerization system or by changing the polymerization temperature, as described in West German Patent Application No. 3127133. I can do it. Furthermore, by adding hydrogen as a chain transfer agent into the polymerization system, it becomes easier to control the molecular weight within an appropriate range. When adding hydrogen into the polymerization system, the molar fraction of hydrogen is preferably 0 mol% or more and 100 mol% or less, more preferably 0 mol% or more and 80 mol% or less, and still more preferably 0 mol% or more and 60 mol% or less.

Furthermore, in the case of using continuous two-stage polymerization in the polymerization of the polyethylene powder of the present embodiment, it is preferable to allow the second-stage polymerization reaction to proceed rapidly. The polymerization rate of polyethylene can be controlled by increasing the amount of the co-catalyst, increasing the polymerization pressure, etc.

In the polymerization of polyethylene powder of this embodiment, when using continuous parallel polymerization in which polymerization reactions are performed in parallel in two reactors with different reaction conditions and mixed, it is necessary to It is preferable to polymerize molecular weight polyethylene and high molecular weight polyethylene with small particle size in the other reactor. The particle size of polyethylene can be controlled by the polymerization pressure, the amount of catalyst added, etc.

Furthermore, when continuous parallel polymerization is used in the polymerization of the polyethylene powder of the present embodiment, it is preferable that the polymerization reaction during polymerization of high molecular weight polyethylene with a small particle size proceed rapidly.

When polymerizing the polyethylene powder of this embodiment, it is also possible to use an antistatic agent such as Stadis 450 manufactured by The Associated Octel Company (distributor Maruwa Bussan) in order to suppress polymer adhesion to the polymerization reactor. It is. Stadis 450 can also be diluted in an inert hydrocarbon medium and added to the polymerization reactor using a pump or the like. The amount added at this time is preferably in the range of 0.10 ppm or more and 20 ppm or less, and more preferably in the range of 0.20 ppm or more and 10 ppm or less, based on the production amount of polyethylene per unit time.

In manufacturing the polyethylene powder of this embodiment, the polyethylene powder is separated from the solvent. Examples of the solvent separation method include a decantation method, a centrifugation method, a filter filtration method, etc., and a centrifugation method is preferable from the viewpoint of high separation efficiency between the polyethylene powder and the solvent.

In manufacturing the polyethylene powder of this embodiment, the catalyst used in the manufacturing process is deactivated. The method for deactivating the catalyst is not particularly limited, but it is preferable to deactivate the catalyst after separating the polyethylene powder and the solvent. By adding a chemical for deactivating the catalyst after separation from the solvent, precipitation of catalyst components etc. dissolved in the solvent can be suppressed. Agents that deactivate the catalyst system include, but are not limited to, oxygen, water, alcohols, glycols, phenols, carbon monoxide, carbon dioxide, ethers, carbonyl compounds, alkynes, etc. .

In manufacturing the polyethylene powder of this embodiment, it is preferable to perform a drying treatment after separating the solvent.

The drying temperature is preferably 70°C or higher and 120°C or lower, more preferably 75°C or higher and 115°C or lower, and even more preferably 80°C or higher and 110°C or lower.

When the drying temperature is 70° C. or higher, efficient drying tends to be possible. When the drying temperature is 120° C. or lower, it tends to be possible to dry the polyethylene powder while suppressing agglomeration and thermal deterioration.

In the production of the polyethylene powder of this embodiment, it is preferable to perform a cooling treatment while stirring immediately after performing a drying treatment.

The cooling temperature is 0°C or lower, more preferably -10°C or lower. When the temperature is 0° C. or lower, the structure peculiar to the polyethylene powder of this embodiment, in which the surface irregularities of the particles become rougher as the powder particle size becomes smaller, tends to be more prominently expressed.

The polyethylene powder of this embodiment may be directly fed into various molding machines for molding, or it may be mixed with organic peroxide and then fed into various molding machines for molding. .

[Organic peroxide]
The organic peroxide (organic peroxide crosslinking agent) that can be used when molding the polyethylene powder of this embodiment contributes to the crosslinking of the polyethylene and creates an atomic group -O-O- in the molecule. Examples of the organic substance include organic peroxides such as dialkyl peroxides, diacyl peroxides, hydroperoxides, and ketone peroxides; organic peresters such as alkyl peresters; and peroxydicarbonates. The above-mentioned organic peroxide is not particularly limited, but specifically, for example, dicumyl peroxide, di-tert-butyl peroxide, 2,5-dimethyl-2,5-di-(tert-butylperoxy)hexane , 2,5-dimethyl-2,5-di-(tert-butylperoxy)hexyne-3, 1,3-bis(tert-butylperoxyisopropyl)benzene, 1,1-bis(tert-butylperoxy)-3 , 3,5-trimethylcyclohexane, n-butyl-4,4-bis(tert-butylperoxy)valerate, benzoyl peroxide, p-chlorobenzoyl peroxide, 2,4-dichlorobenzoyl peroxide, tert-butylperoxybenzoate, tert- Examples include butyl perbenzoate, tert-butyl peroxyisopropyl carbonate, diacetyl peroxide, lauroyl peroxide, tert-butyl cumyl peroxide, α,α'-di(tert-butylperoxy)diisopropylbenzene, and the like. Among these, 2,5-dimethyl-2,5-bis(t-butylperoxy)hexane (trade name "Perhexa 25B" manufactured by NOF Corporation), 2,5-dimethyl-2,5-bis (t-butylperoxy)hexine-3 (trade name "Perhexin 25B" manufactured by NOF Corporation), dicumyl peroxide, 1,1-bis(t-butylperoxy)3,3,5-trimethylcyclohexane preferable.

[Other ingredients]
Furthermore, the polyethylene powder of this embodiment may be used in combination with various known additives as necessary. Examples of the heat stabilizer include, but are not particularly limited to, heat stabilizers such as tetrakis[methylene(3,5-di-t-butyl-4-hydroxy)hydrocinnamate]methane and distearylthiodipropionate; or Weathering stabilizers such as bis(2,2',6,6'-tetramethyl-4-piperidine) sebacate, 2-(2-hydroxy-3-t-butyl-5-methylphenyl)-5-chlorobenzotriazole, etc. etc. Examples of other additives include, for example, neutralizing agents. The neutralizing agent is used as a catcher for chlorine contained in polyethylene powder, or as a molding processing aid. Examples of the neutralizing agent include, but are not limited to, stearates of alkaline earth metals such as calcium, magnesium, and barium.

The content of additives contained in the polyethylene powder of this embodiment is determined by extracting the additives in the polyethylene powder by Soxhlet extraction using tetrahydrofuran (THF) for 6 hours, separating and quantifying the extract by liquid chromatography. It can be found by

The polyethylene powder of this embodiment can be blended with polyethylenes having different intrinsic viscosity, molecular weight distribution, etc., and can also be blended with other resins such as low-density polyethylene, linear low-density polyethylene, polypropylene, and polystyrene.

[Molded object]
The molded body of this embodiment is a molded body of the polyethylene powder of this embodiment described above.
Moreover, the molded article of this embodiment can be obtained by molding the raw material containing the above-mentioned polyethylene powder by various methods.

The molding method of the molded article of this embodiment is not particularly limited, and examples thereof include press molding and extrusion molding. Press molding is a method in which raw materials containing polyethylene powder are uniformly spread in a mold, heated and pressurized to form the mold, and then cooled and taken out. The press-formed body can be used as a product as it is, or it can be finished into a final product through secondary processing such as cutting or slicing. On the other hand, in extrusion molding, a screw extruder or a ram extruder that extrudes by moving a piston back and forth is preferably used. By changing the shape of the exit of the extruder, it is possible to obtain molded bodies of various shapes, such as flat plates, irregularly shaped products, and pipes. Moreover, it is also possible to finish a block molded object such as a round bar or a square column through secondary processing such as cutting or slicing into a final product.

[Application]
The polyethylene powder molded product of this embodiment is not particularly limited, but includes, but is not limited to, lining materials for ships, racks, agricultural equipment, hoppers, and silos; pipes for ore transportation; gears and bearings for machinery; rollers for food transportation; guide rails. It can be used for various purposes such as backing material for skis; artificial bones and joints;

Furthermore, the polyethylene powder of this embodiment can be used as a raw material for microporous membranes; separators for lithium ion secondary batteries and lead-acid batteries; high-strength fibers, etc. by wet molding using a solvent.

Hereinafter, the present embodiment will be described in more detail with reference to specific examples and comparative examples, but the present invention is not limited to the following examples and comparative examples.

The ethylene and hexane used in the examples and comparative examples were dehydrated using MS-3A (manufactured by Showa Union), and the hexane was further deoxidized by degassing under reduced pressure using a vacuum pump. , were used respectively.

[Measurement method and conditions]
The physical properties of the polyethylene powders of Examples and Comparative Examples were measured by the following method.

(1) Viscosity average molecular weight Mv
The viscosity average molecular weights Mv of the polyethylene powders obtained in Examples and Comparative Examples were determined according to the methods shown below in accordance with ISO1628-3 (2010).
First, we weighed 20 mg of polyethylene powder into each dissolving tube, replaced the dissolving tube with nitrogen, and then added 20 mL of decahydronaphthalene (to which 1 g/L of 2,6-di-t-butyl-4-methylphenol was added). In addition, the polyethylene powder was dissolved by stirring at 150° C. for 2 hours to prepare sample solutions.
The falling time (ts) between the marked lines was measured for each of the obtained sample solutions using a Cannon-Fenske viscometer (manufactured by Shibata Kagaku Kikai Kogyo Co., Ltd., product number -100) in a constant temperature bath at 135°C. .
Similarly, sample solutions were prepared in which the amount of polyethylene powder was changed to 10 mg, 5 mg, and 2 mg, and the falling time (ts) between the marked lines was measured under the same conditions.
A sample solution containing only decahydronaphthalene without polyethylene powder was prepared as a blank, and the falling time (tb) was measured under the same conditions.

The reduced viscosity (ηsp/C) of each polyethylene powder was determined according to the following formula.
ηsp/C=(ts/tb-1)/0.1 (unit: dL/g)
Next, we plotted the relationship between the concentration (C) (unit: g/dL) and the reduced viscosity (ηsp/C) of polyethylene powder, derived an approximate linear equation using the least squares method, and extrapolated it to a concentration of 0. The intrinsic viscosity ([η]) was determined for each.
Thereafter, the viscosity average molecular weight Mv (g/mol) was calculated from the value of the limiting viscosity [η] using the following (formula A).
Mv=(5.34×10 ⁴ )×[η] ^1.49 (Formula A)

(2) Difference ΔMv between viscosity average molecular weight Mv ₇₅ and viscosity average molecular weight Mv ₁₅₀
Each polyethylene powder was classified using a screen mesh with openings of 150 μm and 75 μm in accordance with the JIS Z8801 standard, and a 150 μm screen mesh on powder and a 75 μm screen mesh pass powder were separated. The viscosity average molecular weight (Mv ₁₅₀ ) of the resulting 150 μm screen mesh-on powder and the viscosity average molecular weight (Mv ₇₅ ) of the 75 μm screen mesh pass powder were measured according to the measurement method (1) above. The difference ΔMv (g/mol) (=Mv ₇₅ −Mv ₁₅₀ ) was calculated from the obtained viscosity average molecular weights.

(3) Comonomer content The comonomer content (mol%) of each polyethylene powder obtained in Examples and Comparative Examples was measured by ¹³ C-NMR under the following conditions.
Equipment: AVANCEIII 500HD Prodigy (Bruker Biospin)
Observation frequency: 125.77MHz ( ^13C )
Pulse width: 5.0μsec
Pulse repetition time: 5sec
Accumulation count: 10,000 times Measurement temperature: 120℃
Standard: 29.9ppm (PE:Sδδ)
Solvent: o-C ₆ D ₄ Cl ₂
Sample concentration: 0.1g/mL
Sample tube: 5mmφ
The measurement sample was prepared by adding 0.6 mL of o-C ₆ D ₄ Cl ₂ to 60 mg of polyethylene powder and dissolving it while heating at 130°C.

(4) Average particle diameter X ₅₀
100 g of polyethylene powder was weighed into each 200 mL polycup, 1 g of carbon black was added, and the mixture was thoroughly stirred with a spoon. When the stirred polyethylene powder is classified by passing it through sieves with openings of 300 μm, 212 μm, 150 μm, 106 μm, 75 μm, and 53 μm according to the JIS Z 8801 standard, the mass of the polyethylene powder remaining on each of the resulting sieves is calculated based on the mass of the polyethylene powder remaining on each sieve. In the integral curve (integrated distribution on the sieve) integrated from the side, the particle diameter (sieve diameter) that corresponds to 50% by mass was defined as the average particle diameter (μm).

(5) Bulk density a, tap density b, ratio a/b
Bulk density a (g/cm ³ ) and tap density b (g/cm ³ ) were measured using a powder tester PT-X type (manufactured by Hosokawa Micron) as shown below.
The polyethylene powder was poured into ^three 100 cm stainless steel cylindrical containers by vibrating the sample supply device until the polyethylene powder was piled up in the container, and the excess polyethylene powder on the container was scraped off using a blade to separate the measurement samples. The value obtained by measuring this measurement sample was defined as the bulk density a (g/cm ³ ).
In addition, a stainless steel 100 cm ³ cylindrical container was covered with a cap, and the sample supply device was vibrated to let the polyethylene powder flow down, and tapped at a stroke length (tapping height) of 18 mm, a tapping speed of 60 times/min, and a tapping frequency of 180 times. We performed each. Thereafter, a blade was used to scrape off the excess polyethylene powder on the container to prepare measurement samples, and the value obtained by measuring the measurement samples was defined as the tap density b (g/cm ³ ).
Then, the value of the ratio a/b was determined by multiplying by 100 the value obtained by dividing the value of the bulk density a by the value of the tap density b, which was measured as described above.

(6) Remaining melt in the center of the cross section of the extruded molded product Molding of each polyethylene powder molded product was performed using a single-screw extruder with a screw diameter of 25 mm and L (screw length)/D (screw diameter) of 28. went. A full-flight screw was used, and the molding was performed at a barrel temperature of 210°C. A mold with a length of 600 mm was installed at the tip of the extruder, and a molded product of 35 mm square was molded. The molding was carried out at a temperature of 180° C. in the former stage of the mold and 40° C. in the latter stage. Further, the screw rotation speed was adjusted so that the discharge amount was 4 m/hour. The presence or absence of an unmelted part, that is, an unmelted part, in the center of an arbitrary cross section of the produced molded body was visually determined. If there is any undissolved material, it can be identified by the cloudiness in the center. The judgment criteria are shown below.
〇...No melting remains in the center of any cross section ×...Less melting in the center of any cross section

(7) Impact strength of center and end of extrusion molded product Test pieces of 120 mm x 15 mm x 10 mm were cut from the center and 3 mm inside from the end of each extrusion product obtained by the above method, and ISO11542 The impact strength of each specimen was measured using a Charpy impact test in accordance with Standard 2. Five test pieces were prepared, and the average value of the five measurements was calculated. The average value of the impact strength of the center part is divided by the average value of the impact strength of the ends (average value of the impact strength of the center part/average value of the impact strength of the ends). The ratio of impact strength was determined and judged based on the following criteria.
◎...The ratio of the impact strength between the center part and the end part of the extruded product is 0.9 or more. ○...The ratio of the impact strength between the center part and the end part of the extrusion product is 0.8 or more, 0.9 Less than ×...Ratio of impact strength between center and end of extruded product is less than 0.8

(8) Voids in press-formed bodies After pouring 9 kg of each polyethylene powder into a 300 mm square and 100 mm height mold in a hot press molding machine by gravity, level the surface uniformly and set the temperature at 210°C to 10 MPa. After compression molding for 3 hours at a gauge pressure of , press molded bodies were produced by passing through a cooling process in which heating was stopped while the pressure was maintained. The obtained press molded body was cut at intervals of 100 mm, and each of the three cross sections was observed using a 5x magnifying glass. The number of void defects in the cross section of the press-formed product was counted and judged according to the following criteria.
◎...The total number of white dots on the 3 cross sections is 0. 〇...The total number of white dots on the 3 cross sections is 1. ×...The total number of white dots on the 3 cross sections is 2 or more.

[Catalyst synthesis method]
[Preparation of solid catalyst component [A]]
(1) Synthesis of raw material (a-1) 2,000 mL of a hexane solution of 1 mol/L Mg ₆ (C ₄ H ₉ ) ₁₂ Al(C ₂ H ₅ ) ₃ ( (equivalent to 2000 mmol of magnesium and aluminum) were added, and while stirring at 50° C., 146 mL of a 5.47 mol/L n-butanol hexane solution was added dropwise over 3 hours, and after completion, the line was washed with 300 mL of hexane. Furthermore, stirring was continued at 50° C. for 2 hours. After the reaction was completed, the mixture was cooled to room temperature and used as raw material [a-1]. Raw material [a-1] had a total concentration of magnesium and aluminum of 0.704 mol/L.

(2) Synthesis of raw material [a-2] 2,000 mL of a hexane solution of 1 mol/L Mg ₆ (C ₄ H ₉ ) ₁₂ Al(C ₂ H ₅ ) ₃ ( While stirring at 80°C, 240 mL of a hexane solution of 8.33 mol/L methylhydrodiene polysiloxane (manufactured by Shin-Etsu Chemical Co., Ltd.) was fed under pressure, and the mixture was further heated at 80°C for 2 hours. Stirring was continued. After the reaction was completed, the mixture was cooled to room temperature and used as raw material [a-2]. Raw material [a-2] had a total concentration of magnesium and aluminum of 0.786 mol/L.

(3) [A-1] Synthesis of carrier Charge 1,000 mL of a 1 mol/L hexane solution of hydroxytrichlorosilane into an 8L stainless steel autoclave that has been sufficiently purged with nitrogen, and heat the organic magnesium raw material [a-1] at 65°C. 1340 mL of a hexane solution of the compound (equivalent to 943 mmol of magnesium) was added dropwise over 3 hours, and the reaction was continued with stirring at 65° C. for 1 hour. After the reaction was completed, the supernatant was removed and washed four times with 1,800 mL of hexane to obtain a [A-1] carrier. As a result of analysis of this carrier, the magnesium content per gram of solid was 7.5 mmol.

(4) Preparation of solid catalyst component [A] Add 103 mL of a 1 mol/L titanium tetrachloride hexane solution and raw material [a -2] 131 mL was simultaneously added over 3 hours. After the addition, the reaction was continued for 1 hour at 10°C. After the reaction was completed, the supernatant liquid was removed, and unreacted raw material components were removed by washing with hexane four times to prepare a solid catalyst component [A].

[Production of polyethylene powder]
(Example 1)
Polyethylene powder was produced by two-stage polymerization. First, in order to produce a low molecular weight component in the first stage polymerization, hexane, ethylene, hydrogen, and a catalyst were continuously supplied to a vessel type 300L polymerization reactor (1) equipped with a stirring device. The polymerization pressure was kept at 0.31 MPa. The polymerization temperature was maintained at 70°C by jacket cooling. Hexane was fed from the bottom of the polymerization reactor (1) at 40 L/hour. Solid catalyst component [A] was used as a catalyst, and Mg ₆ (C ₄ H ₉ ) ₁₂ Al(C ₂ H ₅ ) ₃ was used as a promoter. The solid catalyst component [A] was added at a rate of 1.5 g/hour between the liquid level and the bottom of the polymerization reactor (1), and the cocatalyst was added at a rate of 10 mmol/hour to the polymerization reactor (1). It was added from halfway between the liquid level and the bottom. Hydrogen was used as the molecular weight regulator, and was supplied so that the molar concentration of hydrogen in the gas phase (hydrogen/(ethylene+hydrogen)) relative to the sum of ethylene and hydrogen was 4.32 mol%. Note that hydrogen was supplied to the gas phase, and ethylene was supplied from the bottom of the polymerization reactor (1).

Next, in order to produce a high molecular weight component in the second stage polymerization, the polymer slurry solution in the first stage polymerization reactor (1) was kept at a pressure of 0.05 MPa and a temperature of 70°C in a flash drum with an internal volume of 300 L. After separating unreacted ethylene and hydrogen, the slurry was introduced into the bottom of a second-stage vessel-type 300L polymerization reactor (2) similar to the polymerization reactor (1) using a slurry pump. Hexane was introduced into the slurry pump at a rate of 110 L/hr. Further, ethylene and a cocatalyst were continuously supplied to the polymerization reactor (2) to perform polymerization. The polymerization pressure was maintained at 0.99 MPa, and the polymerization temperature was maintained at 73°C. The cocatalyst Mg ₆ (C ₄ H ₉ ) ₁₂ Al(C ₂ H ₅ ) ₃ was added to the polymerization reactor (2) at a rate of 50 mmol/hour. Incidentally, ethylene and cocatalyst were supplied from the same position as the polymerization reactor (1). Moreover, hydrogen was not supplied during this second stage polymerization. The second stage polymerization reactor (2) is calculated based on the sum of the mass of the low molecular weight component produced in the first stage polymerization reactor (1) and the mass of the high molecular weight component produced in the second stage polymerization reactor (2). ) The ratio of the mass of the high molecular weight component produced in the second stage polymerization reactor (2) / (the mass of the low molecular weight component produced in the first stage polymerization reactor (1) + The mass of the high molecular weight component produced in the second stage polymerization reactor (2) was polymerized to a high molecular weight of 0.50.The production rate of polyethylene in the polymerization reactor (2) was 20 kg/hour. Ta.

The obtained polymerization slurry was continuously discharged into a flash drum at a pressure of 0.04 MPa so that the level of the polymerization reactor (2) was kept constant, and unreacted ethylene was separated.

Thereafter, the obtained polymerization slurry was continuously sent to a centrifuge so that the level in the polymerization reactor (2) was kept constant, and the polymer (polyethylene powder) and other solvents were separated.

The separated polyethylene powder was stirred and dried at 110°C for 0.5 hour while blowing with nitrogen. In addition, in this drying step, the polyethylene powder after polymerization was sprayed with steam to deactivate the catalyst and co-catalyst. Thereafter, while stirring the dried polyethylene powder, nitrogen blowing was performed at -10° C. for 10 minutes to cool the polyethylene powder. After cooling, 500 ppm of calcium stearate (manufactured by Dainichi Chemical Co., Ltd., C60) was added to the polyethylene powder that had returned to room temperature, and the mixture was uniformly mixed using a Henschel mixer. Subsequently, the polyethylene powder was passed through a sieve with an opening of 425 μm, and what did not pass through the sieve was removed to obtain the polyethylene powder of Example 1 having a viscosity average molecular weight Mv of 193×10 ⁴ g/mol.
Table 1 shows the properties of the obtained polyethylene powder of Example 1.

(Example 2)
In the same manner as in Example 1, polyethylene powder was produced by two-stage polymerization. During the first stage polymerization, 1-butene was continuously supplied from the bottom of the polymerization reactor (1) at 0.90 mol% relative to ethylene, and the gas phase molar concentration of hydrogen relative to the sum of ethylene and hydrogen was adjusted to 1. Except for changing to 40 mol%, stopping the supply of 1-butene during the second stage polymerization, setting the concentration of 1-butene to 0.07 mol% relative to ethylene, changing the polymerization pressure to 1.95 MPa, and changing the polymerization temperature to 60 ° C. The polyethylene powder of Example 2 having a viscosity average molecular weight Mv of 407×10 ⁴ g/mol and a comonomer content of 0.04 mol% was obtained by the same operation as in Example 1. The production rate of polyethylene in the polymerization reactor (2) was 20 kg/hour.
Table 1 shows the properties of the obtained polyethylene powder of Example 2.

(Example 3)
Polyethylene powder was produced by parallel polymerization. Hexane, ethylene, 1-butene, hydrogen, and catalyst were continuously supplied to the same vessel-type 300L polymerization reactor (1) as in Example 1 from the same positions as in Example 2. The polymerization pressure was maintained at 0.30 MPa and the polymerization temperature at 78°C. The flow rate of hexane was 80 L/hour, the supply amount of solid catalyst component [A] was 0.4 g/hour, and the co-catalyst was 5 mmol of a mixture of triisobutyl aluminum and diisobutyl aluminum hydride (9:1 mixture by mass ratio). Polymerization reactor (1) was prepared in the same manner as in Example 2, except that the gas phase molar concentration of hydrogen was changed to 0.50 mol% and the concentration of 1-butene was changed to 0.46 mol% relative to ethylene. A polymerization reaction was carried out. The production rate of polyethylene in the polymerization reactor (1) was 10 kg/hour.

Simultaneously with the polymerization in the polymerization reactor (1), a polymerization reaction was also carried out in a vessel type 300 L polymerization reactor (2) similar to the polymerization reactor (1). Hexane, ethylene, 1-butene, and catalyst were continuously fed from the same positions as in Example 2 above. Note that hydrogen was not added. The polymerization pressure was maintained at 1.23 MPa and the polymerization temperature at 60°C. The flow rate of hexane was 80 L/hour, the supply amount of solid catalyst component [A] was 1.4 g/hour, and the promoter was Mg ₆ (C ₄ H ₉ ) ₁₂ Al(C ₂ H ₅ ) ₃ at 50 mmol/hour. The polymerization reaction in the polymerization reactor (2) was carried out in the same manner as in Example 2, except that the concentration of 1-butene was changed to 0.46 mol% relative to ethylene. The production rate of polyethylene in the polymerization reactor (2) was 10 kg/hour.

The polymerization slurries in the polymerization reactors (1) and (2) are continuously introduced into a stirrer with a pressure of 0.04 MPa and an internal volume of 300 L so that the level in the polymerization reactors is kept constant, and unreacted The polymerization slurry was stirred at the same time as ethylene and hydrogen were separated. Thereafter, by the same operation as in Example 1, a polyethylene powder of Example 3 having a viscosity average molecular weight Mv of 415×10 ⁴ g/mol and a comonomer content of 0.04 mol% was obtained. The total production rate of polyethylene in the polymerization reactor (1) and the polymerization reactor (2) was 20 kg/hour.
Table 1 shows the properties of the obtained polyethylene powder of Example 3.

(Example 4)
Similar to Example 3, polyethylene powder was produced by parallel polymerization. The polymerization pressure in the polymerization reactor (1) was set to 0.31 MPa, the supply amount of the solid catalyst component [A] was set to 0.3 g/hour, the supply amount of the co-catalyst was set to 4 mmol/hour, and the gas phase molar concentration of hydrogen was set to 0.31 MPa. The polymerization reaction in the polymerization reactor (1) was carried out in the same manner as in Example 3, except that 1-butene was not added. The production rate of polyethylene in the polymerization reactor (1) was 5 kg/hour.

The polymerization pressure in the polymerization reactor (2) was set to 2.30 MPa, the polymerization temperature was set to 50°C, the amount of solid catalyst component [A] supplied was set to 1.1 g/hour, and the concentration of 1-butene was set to 0.60 mol%. The polymerization reaction in the polymerization reactor (2) was carried out in the same manner as in Example 3, except for changing to . The production rate of polyethylene in the polymerization reactor (2) was 10 kg/hour.

Thereafter, by the same operation as in Example 3, a polyethylene powder of Example 4 having a viscosity average molecular weight Mv of 630×10 ⁴ g/mol and a comonomer content of 0.03 mol% was obtained. The total production rate of polyethylene in the polymerization reactor (1) and the polymerization reactor (2) was 15 kg/hour.
Table 1 shows the properties of the obtained polyethylene powder of Example 4.

(Example 5)
In the same manner as in Example 2, polyethylene powder was produced by two-stage polymerization. Polymerization reactor (1) and polymerization reactor (2) were prepared in the same manner as in Example 2, except that the polymerization pressure during the second stage polymerization was changed to 0.65 MPa and the cocatalyst supply amount was changed to 10 mmol/hour. A polymerization reaction was carried out.

Thereafter, by the same operation as in Example 2, a polyethylene powder of Example 5 having a viscosity average molecular weight Mv of 404×10 ⁴ g/mol and a comonomer content of 0.03 mol% was obtained. The production rate of polyethylene in the polymerization reactor (2) was 20 kg/hour.
Table 1 shows the properties of the obtained polyethylene powder of Example 5.

(Example 6)
In the same manner as in Example 2, polyethylene powder was produced by two-stage polymerization. After carrying out the polymerization reaction in the polymerization reactor (1) and the polymerization reactor (2), the procedure was carried out in the same manner as in Example 2, except that the nitrogen blowing at -10°C for 10 minutes on the dried powder was omitted. .

Thereafter, by the same operation as in Example 2, a polyethylene powder of Example 6 having a viscosity average molecular weight Mv of 403×10 ⁴ g/mol and a comonomer content of 0.04 mol% was obtained. The production rate of polyethylene in the polymerization reactor (2) was 20 kg/hour.
Table 1 shows the properties of the obtained polyethylene powder of Example 6.

(Comparative example 1)
Polyethylene powder was produced by one-stage polymerization. Hexane, ethylene, hydrogen, and a catalyst were continuously supplied to a vessel-type 300 L polymerization reactor (1) similar to Example 1 from the same positions as in Example 1. The polymerization pressure was maintained at 0.30 MPa, and the polymerization temperature was maintained at 75°C. The flow rate of hexane was set to 80 L/hour, the amount of solid catalyst component [A] supplied was set to 0.3 g/hour, and a mixture of triisobutylaluminum and diisobutylaluminum hydride (9:1 mixture in mass ratio) was added as a cocatalyst. The polymerization reaction in the polymerization reactor (1) was carried out in the same manner as in Example 1, except that the gas phase molar concentration of hydrogen was changed to 5 mmol/hour and 0.27 mol%. The production rate of polyethylene in the polymerization reactor (1) was 10 kg/hour.

Thereafter, Comparative Example 1 having a viscosity average molecular weight Mv of 330×10 ⁴ g/mol was prepared in the same manner as in Example 1 except that the dried powder was not subjected to nitrogen blowing at −10° C. for 10 minutes. of polyethylene powder was obtained.
Table 1 shows the properties of the polyethylene powder of Comparative Example 1 obtained.

(Comparative example 2)
Polyethylene powder was produced by two-stage polymerization in the same manner as in Example 2 above. Except that the polymerization pressure during the second stage polymerization was changed to 0.65 MPa, the co-catalyst supply amount was changed to 10 mmol/hour, and the powder after drying was not blown with nitrogen at -10°C for 10 minutes. By the same operation as in Example 2, a polyethylene powder of Comparative Example 2 having a viscosity average molecular weight Mv of 411×10 ⁴ g/mol and a comonomer content of 0.04 mol% was obtained. The production rate of polyethylene in the polymerization reactor (2) was 20 kg/hour.
Table 1 shows the properties of the obtained polyethylene powder of Comparative Example 2.

(Comparative example 3)
Polyethylene powder was produced by two-stage polymerization in the same manner as in Example 1 above. In Comparative Example 3, a high molecular weight component was polymerized in the first stage polymerization, and a low molecular weight component was polymerized in the second stage polymerization. During the first stage polymerization, the polymerization pressure was changed to 0.27 MPa and the polymerization temperature was changed to 74°C without supplying hydrogen, and during the second stage polymerization, the polymerization pressure was changed to 0.56 MPa and the polymerization temperature was changed to 74°C. at 78° C., the cocatalyst supply rate was changed to 10 mmol/hour, 1-butene was supplied at a concentration of 1.00 mol% relative to ethylene, hydrogen was supplied at a gas phase molar concentration of 0.20 mol%, The same procedure as in Example 1 was carried out to obtain a powder with a viscosity average molecular weight Mv of 393×10 ⁴ g/mol and a comonomer content of 0.5 g/mol, except that the powder after drying was not blown with nitrogen at −10° C. for 10 minutes. 05 mol% of polyethylene powder of Comparative Example 3 was obtained. The production rate of polyethylene in the polymerization reactor (2) was 20 kg/hour.
Table 1 shows the properties of the obtained polyethylene powder of Comparative Example 3.

(Comparative example 4)
Polyethylene powder was produced by two-stage polymerization in the same manner as in Example 1 above. In Comparative Example 4, similarly to Comparative Example 3, a high molecular weight component was polymerized in the first stage polymerization, and a low molecular weight component was polymerized in the second stage polymerization. During the first stage polymerization, the polymerization pressure was changed to 0.27 MPa and the polymerization temperature was changed to 74°C without supplying hydrogen, and during the second stage polymerization, the polymerization pressure was changed to 1.68 MPa and the polymerization temperature was changed to 78°C. , except that the cocatalyst supply rate was changed to 50 mmol/hour, 1-butene was supplied at a concentration of 1.00 mol% relative to ethylene, and hydrogen was supplied at a gas phase molar concentration of 0.20 mol%. By the same operation as in Example 1, a polyethylene powder of Comparative Example 4 having a viscosity average molecular weight Mv of 391×10 ⁴ g/mol and a comonomer content of 0.06 mol% was obtained. The production rate of polyethylene in the polymerization reactor (2) was 20 kg/hour.
Table 1 shows the properties of the polyethylene powder of Comparative Example 4 obtained.

The polyethylene powder of the present invention can be used industrially as a raw material for various molded articles; microporous membranes, separators, and high-strength fibers.

Claims (8)

having a viscosity average molecular weight Mv of 100,000 (g/mol) to 10,000,000 (g/mol),
having an average particle diameter _X50 of 50 μm to 200 μm on a cumulative mass basis,
The viscosity average molecular weight Mv ₇₅ (g/mol) of the pass powder when classified with a screen mesh with an opening of 75 μm and the viscosity average molecular weight Mv ₁₅₀ (g/mol) of the on-powder when classified with a screen mesh with an opening of 150 μm. The difference ΔMv (here, ΔMv = Mv ₇₅ - Mv ₁₅₀ ) is greater than 0 (g/mol) and less than or equal to 4,000,000 (g/mol),
The ratio a/b of the bulk density a (g/cm ³ ) to the tap density b (g/cm ³ ) is 83.0 (%) or more;
polyethylene powder. The polyethylene powder according to claim 1, wherein the ratio a/b is greater than 88.0 (%). The polyethylene powder according to claim 1 or 2, wherein the difference ΔMv is greater than 10 (g/mol) and less than 3,000,000 (g/mol). A molded article obtained by molding a raw material containing the polyethylene powder according to any one of claims 1 to 3. A press-molded product obtained by press-molding a raw material containing the polyethylene powder according to any one of claims 1 to 3. An extrusion molded product obtained by extrusion molding a raw material containing the polyethylene powder according to any one of claims 1 to 3. A microporous membrane using the polyethylene powder according to any one of claims 1 to 3. A high-strength fiber using the polyethylene powder according to any one of claims 1 to 3.