CN116769086A

CN116769086A - Polyethylene powder and molded article obtained using the same

Info

Publication number: CN116769086A
Application number: CN202310253881.7A
Authority: CN
Inventors: 前田聪志; 石川雅彦; 高桥洋介; 浜田至亮
Original assignee: Asahi Kasei Corp
Current assignee: Asahi Kasei Corp
Priority date: 2022-03-18
Filing date: 2023-03-16
Publication date: 2023-09-19
Also published as: TW202344525A; JP2023138477A

Abstract

The present invention relates to a polyethylene powder and a molded article obtained using the same. The present invention provides a polyethylene powder which has excellent processability, has excellent production speed during molding of a molded body, and can improve qualified rate, uniformity of physical properties and the like by suppressing strength reduction caused by void defects or insufficient fusion, and a molded body obtained by using the polyethylene powder. A polyethylene powder, wherein the polyethylene powder has a viscosity average molecular weight Mv of 100,000 (g/mol) to 10,000,000 (g/mol) and an average particle diameter X of 50 μm to 200 μm on a cumulative mass basis ₅₀ Viscosity average molecular weight Mv of undersize powder when classified by a sieve having a mesh size of 75 μm ₇₅ (g/mol) and viscosity average molecular weight Mv of the on-screen powder when classified by a sieve having a mesh size of 150. Mu.m ₁₅₀ (g/mol) difference Δmv (here, Δmv=mv ₇₅ ‑Mv ₁₅₀ ) Greater than 0 (g/mol) and equal to or less than 4,000,000 (g/mol), and bulk density a (g/cm) ³ ) Relative to tap density b (g/cm ³ ) The ratio a/b of (2) is 83.0 (%) or more.

Description

Polyethylene powder and molded article obtained using the same

Technical Field

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

Background

The ultra-high molecular weight polyethylene powder having a higher molecular weight than general-purpose polyethylene is excellent in abrasion resistance, impact resistance, self-lubricity, chemical resistance, low temperature characteristics, dimensional stability, light weight, safety to foods, and the like, as compared with other engineering plastics or metals. Therefore, the molded article is used in various fields such as lining materials for ships and trucks, gears and bearings for machinery, rollers for food transportation, backing materials for snowboards, artificial bones and artificial joints.

The ultrahigh molecular weight polyethylene has low melt fluidity because of its high molecular weight, and it is difficult to melt-knead the resin. Therefore, as a molding method, molding is often performed by press molding, ram extrusion molding, screw extrusion molding, or the like, in which a powdery raw material resin is directly heated and compressed. Further, as problems in molding of ultra-high molecular weight polyethylene, there are mentioned: the processing speed is low, and the production rate is poor; void defects or strength decrease due to poor filling of the powder and insufficient fusion of the powder, low yield associated therewith, and particularly, the larger the molded body, the larger the difference in physical properties between the central portion and the end portion of the molded body. These problems prevent the use of ultra-high molecular weight polyethylene molded articles in a wider range.

To solve these problems, several methods have been studied. For example, in patent document 1, the following method is reported: by mixing a low molecular weight polyethylene having a molecular weight of 5,000 to 20,000 with an ultra high molecular weight polyethylene having a molecular weight of 100 ten thousand or more, productivity can be improved.

In addition, patent document 2 reports the following method: processability can be improved by narrowing the molecular weight distribution using a special cross-linked metallocene catalyst system.

Further, in patent document 3, the following method is reported: by narrowing the molecular weight distribution and the particle size distribution, productivity in compression molding can be improved.

In addition, patent document 4 reports the following method: by performing a special heat treatment on the powder, it is possible to adjust the powder spreading parameters defined alone, suppress the occurrence of void defects, and improve the yield.

Prior art literature

Patent literature

Patent document 1: japanese patent laid-open No. 57-177036

Patent document 2: japanese patent application laid-open No. 2009-514997

Patent document 3: japanese patent application laid-open No. 2017-141312

Patent document 4: WO2020/171017

Disclosure of Invention

Problems to be solved by the invention

According to the method described in patent document 1, although an improvement in the production speed at the time of molding is confirmed, at the same time, there is a problem that the physical properties of the molded article, particularly the abrasion resistance, are greatly reduced. In addition, improvement of the yield and fluctuation of physical properties are not considered.

According to the method described in patent document 2, it is reported that processability can be improved by narrowing the molecular weight distribution. However, the effect is not specifically shown, and improvement of the yield and fluctuation of physical properties are not considered.

According to the method described in patent document 3, improvement of processability by narrowing the molecular weight distribution and the particle size distribution has been reported. It is presumed that the composition has an effect in terms of production speed and suppression of void defects, but the effect is not specifically exhibited, and improvement of quality and fluctuation of physical properties are not considered.

According to the method described in patent document 4, it is reported that the generation of void defects can be suppressed and the yield can be improved. However, the properties of the thicker large-size molded articles have not been satisfactory. In addition, improvement in production speed and fluctuation in physical properties are not considered.

In view of the above problems, an object of the present invention is to provide a polyethylene powder which has excellent processability, is excellent in production speed at the time of molding a molded article, and can improve yield, uniformity of physical properties, and the like by suppressing a decrease in strength due to void defects or insufficient fusion, and a molded article or the like obtained using the polyethylene powder.

Means for solving the problems

The present inventors have made intensive studies to solve the above problems, and as a result, have surprisingly found that a polyethylene powder having a difference in viscosity average molecular weight between a powder having a large particle diameter and a powder having a small particle diameter and a ratio of a predetermined bulk density to tap density can solve the above problems when classifying the polyethylene powder by a screen having a predetermined mesh size, and have completed the present invention. Namely, the present invention is as follows.

[1]

A polyethylene powder, wherein,

the polyethylene powder has a viscosity average molecular weight Mv of 100,000 (g/mol) to 10,000,000 (g/mol),

the polyethylene powder has an average particle diameter X of 50-200 mu m based on the accumulated mass ₅₀ ，

The polyethylene powder was subjected to a sieve having a mesh size of 75. Mu.mViscosity average molecular weight Mv of undersize powder at fractionation ₇₅ (g/mol) and viscosity average molecular weight Mv of the on-screen powder when classifying the polyethylene powder with a sieve having a mesh size of 150 μm ₁₅₀ (g/mol) difference Δmv (here, Δmv=mv ₇₅ -Mv ₁₅₀ ) Greater than 0 (g/mol) and equal to or less than 4,000,000 (g/mol), and

bulk density a (g/cm) ³ ) Relative to tap density b (g/cm ³ ) The ratio a/b of (2) is 83.0 (%) or more.

[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 equal to or less than 3,000,000 (g/mol).

[4]

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

[5]

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

[6]

An extrusion molded article obtained by extrusion molding a raw material comprising the polyethylene powder according to any one of [1] to [3 ].

[7]

A microporous membrane, wherein the microporous membrane uses the polyethylene powder according to any one of [1] to [3 ].

[8]

A high-strength fiber, wherein the high-strength fiber uses the polyethylene powder according to any one of [1] to [3 ].

Effects of the invention

According to the present invention, there can be provided a polyethylene powder having a specific difference Δmv between viscosity average molecular weights and a specific ratio a/b of bulk density a to tap density b, which is excellent in processability, which is excellent in production speed at the time of molding a molded article, and which can improve yield, physical property uniformity and the like, a molded article obtained using the polyethylene powder, and the like.

Detailed Description

Hereinafter, an embodiment of the present invention (hereinafter referred to as "the present embodiment") will be described in detail. The following embodiments are examples for illustrating the present invention, and the present invention is not limited thereto. That is, the present invention can be implemented with any modification within a range not departing from the gist thereof. In the present specification, the term "to" is used to indicate that numerical values or physical values are inserted before and after the term "to" and is used as a range including values before and after the term.

[ polyethylene powder ]

The polyethylene powder (hereinafter also simply referred to as "powder") of the present embodiment has a viscosity average molecular weight Mv of 100,000 (g/mol) to 10,000,000 (g/mol) and an average particle diameter X of 50 μm to 200 μm on a cumulative mass basis ₅₀ Viscosity average molecular weight Mv of undersize powder when classified by a sieve having a mesh size of 75 μm ₇₅ (g/mol) and viscosity average molecular weight Mv of the on-screen powder when classified by a sieve having a mesh size of 150. Mu.m ₁₅₀ (g/mol) difference Δmv (here, Δmv=mv ₇₅ -Mv ₁₅₀ ) Greater than 0 (g/mol) and equal to or less than 4,000,000 (g/mol), and bulk density a (g/cm) ³ ) Relative to tap density b (g/cm ³ ) The ratio a/b of (2) is 83.0 (%) or more.

The polyethylene powder of the present embodiment refers to a collection of polyethylene particles.

Examples of the polyethylene constituting the polyethylene powder according to the present embodiment include: ethylene homopolymers, or copolymers of ethylene with other comonomers, and the like, but are not limited thereto. The copolymer may be a ternary random copolymer.

The other comonomers are not particularly limited, and examples thereof include: alpha-olefins, vinyl compounds, and the like.

The α -olefin is not particularly limited, and examples thereof include: alpha-olefins having 3 to 20 carbon atoms, and the like. Specific examples of the α -olefin having 3 to 20 carbon atoms include: 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 them, propylene and 1-butene are preferable as the α -olefin from the viewpoints of impact resistance, abrasion resistance, heat resistance and rigidity of the molded body of the polyethylene powder.

The vinyl compound is not particularly limited, and examples thereof include: vinylcyclohexane, styrene, derivatives thereof, and the like.

In addition, a non-conjugated polyene such as 1, 5-hexadiene or 1, 7-octadiene may be used as the other comonomer, if necessary.

The other comonomers may be used singly or in combination of two or more.

The content of the other comonomer is not particularly limited, but the content of the other comonomer is preferably 0.8 mol% or less, more preferably 0.7 mol% or less, and still more preferably 0.6 mol% or less, based on the polyethylene. When the amount of the other comonomer is adjusted to 0.8 mol% or less, a molded article excellent in impact resistance, abrasion resistance and rigidity tends to be easily obtained. In the case of using the other comonomer, the lower limit of the amount of the other comonomer is not particularly limited, and the amount of the other comonomer may be more than 0 mol% with respect to the polyethylene.

The comonomer content of the polyethylene can be confirmed by NMR or infrared analysis described in examples described later.

[ viscosity average molecular weight Mv ]

The polyethylene powder of the present embodiment has a viscosity average molecular weight Mv (g/mol) of 100,000 or more and 10,000,000 or less, preferably 500,000 or more and 9,000,000 or less, 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 the present embodiment tend to be further improved. Further, when the viscosity average molecular weight Mv is 10,000,0000 (g/mol) or less, the melting of the powder and the fusion of the powder to each other are promoted at the time of molding the powder, and thus the production speed at the time of molding processing is further improved, void defects due to insufficient fusion are further suppressed, and the fluctuation of physical properties in the molded body is also further reduced.

The viscosity average molecular weight Mv of the polyethylene powder can be adjusted by using a catalyst described later and appropriately adjusting the polymerization conditions and the like. Specific examples of the polymerization conditions include: hydrogen is allowed to exist in the polymerization system and/or the polymerization temperature is changed, etc. The viscosity average molecular weight Mv of the polyethylene powder can be obtained by the method described in examples described later.

[ average particle diameter X ] ₅₀ ]

The average particle diameter X of the polyethylene powder of the present embodiment ₅₀ The particle diameter (sieve analysis particle diameter), i.e., median particle diameter, at a cumulative mass of 50 mass%. Average particle diameter X of polyethylene powder ₅₀ The calculation of (2) can be performed by the method described in examples described later. Average particle diameter X of polyethylene powder ₅₀ 50 μm to 200. Mu.m, preferably 60 μm to 175. Mu.m, more preferably 70 μm to 150. Mu.m. By mean particle size X of the polyethylene powder ₅₀ The polyethylene powder is easily melted to 200 μm or less, and as a result, the production speed at the time of processing is increased, and the occurrence of void defects due to insufficient fusion can be suppressed, and the tendency of fluctuation in physical properties in the molded body can be reduced. In addition, the average particle diameter X of the polyethylene powder ₅₀ Since the particle size is 50 μm or more, scattering of the powder can be suppressed, and thus the handling property tends to be improved when the powder is handled.

Average particle diameter X of polyethylene powder ₅₀ Can be controlled by sieving with a screen of a specific mesh size. In the present embodiment, polyethylene powder passing through a screen having a mesh size of 425 μm in a standard screen according to JIS Z8801 is particularly preferably used from the viewpoint of solubility in a solvent.

[ Difference ΔMv ]

The difference Δmv is the viscosity average molecular weight Mv of a powder passing through a mesh (hereinafter also referred to as "undersize powder") when classifying a polyethylene powder with a mesh size of 75 μm ₇₅ And a powder (hereinafter also referred to as "powder on screen") remaining on the screen when the polyethylene powder is classified by a screen having a screen mesh size of 150 μm ₁₅₀ And (3) a difference. Specifically, the difference Δmv is according to the formula: Δmv=mv ₇₅ -Mv ₁₅₀ And (3) the calculated value. The difference Δmv is greater than 0 (g/mol) and equal to or less than 4,000,000 (g/mol), preferably greater than 5 (g/mol) and equal to or less than 3,500,000 (g/mol), more preferably greater than 10 (g/mol) and equal to or less than 3,000,000 (g/mol). When 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, melting of the large particle size powder with a slow heat transfer and fusion of the powders to each other are easier, the production speed at the time of molding is further increased, void defects due to insufficient fusion are further suppressed, and the fluctuation of physical properties in the molded body is also further reduced. On the other hand, when the difference Δmv is 4,000,000 (g/mol) or less, it is possible to suppress 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. In addition, the viscosity average molecular weight Mv of the small particle size powder can be suppressed from becoming too high, and as a result, melting of the small particle size powder and fusion of the powder to each other are facilitated, the production speed at the time of molding is further increased, void defects caused by insufficient fusion are further suppressed, and the fluctuation of physical properties in the molded body is also further reduced.

Viscosity average molecular weight Mv ₇₅ And a viscosity average molecular weight Mv ₁₅₀ The viscosity average molecular weight Mv can be obtained by the method described in the examples to be described later ₇₅ And a viscosity average molecular weight Mv ₁₅₀ The difference Δmv can be calculated from the above equation.

The method for controlling the difference Δmv to be in the range of 0 (g/mol) or more and 4,000,000 (g/mol) or less is not particularly limited, and examples thereof include a selective polymerization method. When specific examples are enumerated, there may be enumerated: a method of using a catalyst described later in the polymerization reaction of polyethylene and performing the polymerization in two steps (hereinafter also referred to as "two-step polymerization"); a method of polymerizing in the first polymerization stage of the two-stage polymerization to obtain a polyethylene having a lower molecular weight than that of the second polymerization stage, and the like.

The reason why the difference Δmv can be controlled by the above method will be described. In the first polymerization stage, a low molecular weight polyethylene having a certain particle size distribution is produced. In the case of the large particle diameter powder after the first polymerization step, the catalyst activity is lowered and the speed of diffusing the ethylene to the catalyst in the center of the powder becomes slow, so that the polymerization reaction is difficult to proceed in the polymerization of the high molecular weight polyethylene in the second step. On the other hand, with respect to the small particle diameter powder after the first polymerization step, the catalyst activity is not reduced as much as with the large particle diameter powder, and the speed of the catalyst in which ethylene diffuses to the center of the powder is relatively high, so that the polymerization reaction is easy to proceed at the time of the polymerization of the high molecular weight polyethylene in the second step. As a result, as the particle size of the powder after the second polymerization step becomes smaller, the viscosity average molecular weight Mv can be increased. The method of controlling Δmv to be within the predetermined range includes: adjusting the molecular weight of the first step and the second step, adjusting the particle size distribution of the first step, and the like.

As other methods for controlling the difference Δmv to be in the range of greater than 0 (g/mol) and equal to or less than 4,000,000 (g/mol), the following methods are exemplified: a polymerization method (hereinafter also referred to as "parallel polymerization") in which a polymerization reaction is carried out in parallel using a catalyst described later and using two polymerizers and then a polymerization slurry is mixed is used, and a low molecular weight polyethylene having a large particle diameter and a high molecular weight polyethylene having a small particle diameter, which are obtained separately, are mixed. The method of controlling the particle size of the powder includes adjusting the activity of the catalyst, and specifically, changing the polymerization pressure, the amount of the catalyst added, and the like.

Further, as another method of controlling the difference Δmv to be in the range of more than 0 (g/mol) and not more than 4,000,000 (g/mol), there is a method of mixing a plurality of polyethylene powders different in particle size and viscosity average molecular weight Mv by dry blending.

[ proportion a/b ]

In the present specification, bulk density a means apparent density (g/cm) when polyethylene powder is allowed to fall freely ³ ) Tap density b is the apparent density (g/cm) of the free-falling powder after 180 taps ³ ). The bulk density a and tap density b can be obtained by a method described in examples described later, and the values of the bulk density a and tap density b are expressed by the following formula: the ratio a/b=100×a/b can be obtained as a value of the ratio a/b (%). That is, the closer the ratio a/b is to 100 (%), the more tightly the powder is filled in the free-falling stage. The ratio a/b is 83.0 (%) or more, preferably more than 86.0 (%), more preferably more than 88.0 (%). The upper limit is not particularly limited as long as it is 100 (%) or less. When the ratio a/b is 83.0 (%) or more, the powder is easily and tightly packed, and the powder is easily fused with each other, so that occurrence of void defects during molding processing can be suppressed, and variation in physical properties in the molded body tends to be further reduced.

The method of controlling the ratio a/b to 83.0 (%) or more is not particularly limited, and examples thereof include: the polymerization method, polymerization conditions, and powder cooling method are designed.

First, a specific example of a polymerization method and polymerization conditions for controlling the ratio a/b to 83.0 (%) or more will be described. The polymerization method may be a method using the two-stage polymerization or the parallel polymerization. As the polymerization conditions for the two-stage polymerization, there may be mentioned: the polymerization reaction in the second step is rapidly carried out; the polymerization conditions for the parallel polymerization include: the polymerization is carried out in one polymerizer to obtain polyethylene having a large particle diameter, in another polymerizer to obtain polyethylene having a small particle diameter, and the polymerization reaction is rapidly carried out when the polymerization is carried out to obtain polyethylene having a small particle diameter. Specific examples of the polymerization conditions under which the polymerization reaction proceeds rapidly include: a large amount of a cocatalyst to be described later is added, the polymerization pressure is increased, and the like. By producing polyethylene powder under such polymerization conditions by using such a polymerization method, the surface roughness of the powder particles becomes rough as the particle size becomes smaller, and the ratio a/b can be increased as compared with the conventional one by the specific powder morphology. By forming the specific powder morphology, the contact area between the large particle size powder having less surface irregularities and the small particle size powder having rough surface irregularities is reduced, and the small particle size powder is tightly filled in the gaps of the large particle size powder in the free fall stage, whereby the value of the ratio a/b can be increased. When both the large particle size powder and the small particle size powder roughen the surface irregularities, the surface irregularities are resistant to each other, and the value of the ratio a/b becomes small.

The reason why the surface roughness of the powder particles becomes rough as the particle diameter becomes smaller by the above-described method will be described by taking the two-stage polymerization in the above specific example as an example. As described above, the small particle size powder after the first polymerization step is likely to undergo the second polymerization reaction, i.e., particle growth, as compared with the large particle size powder, and the small particle size powder is difficult to disperse due to stress at the time of particle growth, and therefore cracks are likely to occur on the powder surface as compared with the large particle size powder, with the result that the powder after the two polymerization steps becomes rough as the particle size becomes smaller.

Next, a method of cooling the powder will be described as a specific example for controlling the ratio a/b to 83.0 (%) or more. After the polymer powder is dried, the powder is stirred and quenched, whereby the surface roughness of the powder particles can be roughened as the particle size becomes smaller. This is because the small particle size powder is easy to cool and the stress accompanying volume shrinkage upon cooling is difficult to disperse.

[ method for producing polyethylene powder ]

[ catalyst component ]

The catalyst component used in the production of the polyethylene powder of the present embodiment is not particularly limited, and examples thereof include general ziegler-natta catalysts.

(Ziegler-Natta catalyst)

The Ziegler-Natta catalyst is preferably a catalyst for olefin polymerization comprising a solid catalyst component [ A ] produced by reacting an organomagnesium compound (A-1) soluble in an inert hydrocarbon solvent represented by the following formula (1) with a titanium compound (A-2) represented by the following formula (2), and an organometallic compound component [ B ].

(A-1)：(M ¹ ) _α (Mg) _β (R ² ) _a (R ³ ) _b (Y ¹ ) _c … … (1)

(in formula 1, M ¹ Is a metal atom belonging to the group consisting of groups 12, 13 and 14 of the periodic Table of elements, R ² And R is ³ Is a hydrocarbon group having 2 to 20 carbon atoms, Y ¹ Is hydrocarbyloxy, siloxy, allyloxy, amino, amido, -n=c-R ⁴ ,R ⁵ 、-SR ⁶ (herein, R ⁴ 、R ⁵ And R is ⁶ Represents a hydrocarbon group having 1 to 20 carbon atoms. In the case of c being 2, Y ¹ May be different from each other), and the β -keto acid residues, α, β, a, b, and c are real numbers satisfying the following relationship. 0.ltoreq.α, 0.ltoreq.β, 0.ltoreq.a, 0.ltoreq.b, 0.ltoreq.c, 0.ltoreq.a+b, 0.ltoreq.c/(α+β) ltoreq.2, nα+2β=a+b+c (where n represents M) ¹ Is not limited, and is not limited. ))

(A-2)：Ti(OR ⁷ ) _d X ¹ _(4-d) … … (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, X ¹ Is a halogen atom. )

The inert hydrocarbon solvent used in the reaction of the organomagnesium compound (A-1) and the titanium compound (A-2) is not particularly limited, and examples thereof include: 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 described.

The organomagnesium compound (A-1) is represented in the form of an organomagnesium complex that is soluble in an inert hydrocarbon solvent, and contains all of a dialkylmagnesium compound and a complex of this compound with other metal compounds. The relation nα+2β=a+b+c of the symbols α, β, a, b, c represents the valency of the metal atom and the stoichiometry of the substituent.

In the formula (1), R is ² And R is ³ The hydrocarbon group having 2 to 20 carbon atoms is not particularly limited, and examples thereof include an alkyl group, a cycloalkyl group, and an aryl group, and specifically, examples thereof include: ethyl, propyl, butyl, pentyl, hexyl, octyl, decyl, cyclohexyl, phenyl, and the like. Alkyl groups are particularly preferred. In the case of alpha > 0, as metal atom M ¹ Metal atoms belonging to the group consisting of group 12, group 13 and group 14 of the periodic table of elements may be used, and examples thereof include: zinc, boron, aluminum, etc. Aluminum and zinc are particularly preferred.

For magnesium relative to metal atom M ¹ The ratio β/α is not particularly limited, but is preferably 0.1 to 30, more preferably 0.5 to 10. In addition, in the case of using a predetermined organomagnesium compound having α=0, for example, in R ² In the case of 1-methylpropyl group, etc., the compound is soluble in an inert hydrocarbon solvent, and preferable results can be obtained in the present embodiment.

In the above (formula 1), R in the case where α=0 is recommended ² 、R ³ Any one of the three groups (1), group (2) and group (3) shown below is satisfied.

Group (1): r is R ² And R is ³ At least one of them is a secondary or tertiary alkyl group having 4 or more and 6 or less carbon atoms, preferably R ² And R is ³ Are all alkyl groups having 4 to 6 carbon atoms, and R ² And R is ³ At least one of which is a secondary or tertiary alkyl group.

Group (2): r is R ² And R is ³ Is alkyl having different carbon numbers, 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.

Group (3): r is R ² And R is ³ At least one of them is a hydrocarbon group having 6 or more carbon atoms, preferably R ² And R is ³ An alkyl group having 12 or more carbon atoms as the sum of the carbon atoms contained in the above-mentioned aromatic hydrocarbon.

These groups are specifically shown below.

In the above group (1), examples of the secondary alkyl group or tertiary alkyl group having 4 or more and 6 or less carbon atoms include: 1-methylpropyl group, 2-methylpropyl group, 1-dimethylethyl group, 2-methylbutyl group, 2-ethylpropyl group, 2-dimethylpropyl group, 2-methylpentyl group, 2-ethylbutyl group, 2-dimethylbutyl group, 2-methyl-2-ethylpropyl group and the like. 1-methylpropyl is particularly preferred.

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

The hydrocarbon group having 6 or more carbon atoms in the group (3) is not particularly limited, and examples thereof include: hexyl, heptyl, octyl, nonyl, decyl, phenyl, 2-naphthyl and the like. Among the hydrocarbon groups, alkyl groups are preferable, and among the alkyl groups, hexyl groups and octyl groups are particularly preferable.

In general, when the number of carbon atoms contained in an alkyl group increases, the carbon atoms tend to be easily dissolved in an inert hydrocarbon solvent, and the viscosity of the solution tends to increase. Thus, in operation, it is preferable to use an appropriately long chain alkyl group. The organomagnesium compound can be used after being diluted with an inert hydrocarbon solvent, and even if a small amount of a lewis basic compound such as an ether, an ester, or an amine is contained or remained in the solution, the organomagnesium compound can be used without any problem.

Then, for Y ¹ An explanation is given.

In the above formula (1), Y ¹ Is hydrocarbyloxy, siloxy, allyloxy, amino, amido, -n=c-R ⁴ ,R ⁵ 、-SR ⁶ (herein, R ⁴ 、R ⁵ And R is 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), R is ⁴ 、R ⁵ And R is ⁶ The hydrocarbon group represented is preferably a hydrocarbon group having carbon atomsAn alkyl group or an aryl group having 1 to 12 carbon atoms, more preferably an alkyl group or an aryl group having 3 to 10 carbon atoms. There are no particular restrictions, and examples thereof include: methyl, ethyl, propyl, 1-methylethyl, butyl, 1-methylpropyl, 1-dimethylethyl, pentyl, hexyl, 2-methylpentyl, 2-ethylbutyl, 2-ethylpentyl, 2-ethylhexyl, 2-ethyl-4-methylpentyl, 2-propylheptyl, 2-ethyl-5-methyloctyl, octyl, nonyl, decyl, phenyl, naphthyl and the like. Butyl, 1-methylpropyl, 2-methylpentyl and 2-ethylhexyl are particularly preferred.

In the above formula (1), Y ¹ Preferably hydrocarbyloxy or siloxy.

The hydrocarbyloxy group is not particularly limited, and for example, preferable is: methoxy, ethoxy, propoxy, 1-methylethoxy, butoxy, 1-methylpropoxy, 1-dimethylethoxy, pentoxy, hexoxy, 2-methylpentoxy, 2-ethylbutoxy, 2-ethylpentoxy, 2-ethylhexoxy, 2-ethyl-4-methylpentoxy, 2-propylheptoxy, 2-ethyl-5-methyloctanoxy, octoxy, phenoxy, naphthoxy. Particularly preferred are: butoxy, 1-methylpropoxy, 2-methylpentoxy and 2-ethylhexyloxy.

The siloxy group is not particularly limited, and for example, preferable is: hydrodimethylsiloxy, ethylhydrosilyloxy, diethylhydrosilyloxy, trimethylsiloxy, ethyldimethylsilyloxy, diethylmethylsiloxy, triethylsiloxy and the like. Particularly preferred are: hydrodimethylsiloxy, ethylmethylsiloxy, diethylhydrosiloxy, trimethylsiloxy.

The method for synthesizing the organomagnesium compound (A-1) is not particularly limited, and can be synthesized, for example, by: to the formula R ² MgX ¹ And R is ² Mg(R ² X is as defined above ¹ Is a halogen atom) and are of the group consisting of the organomagnesium compounds of the formula M ¹ R ³ _n And M ¹ R ³ _(n-1) H(M ¹ And R is ³ For the foregoingN represents M ¹ The valences of the atoms) of the group consisting of (a) in an inert hydrocarbon solvent at a temperature of from 25 ℃ to 150 ℃ and, if desired, subsequently reacting a metal organic compound of the group consisting of the compounds of the formula Y ¹ -H(Y ¹ In the meaning indicated above) or by reacting a compound represented by Y ¹ The organomagnesium compound and/or the organoaluminum compound of the indicated functional group. Wherein the organomagnesium compound is dissolved in an inert hydrocarbon solvent and is represented by the formula Y ¹ In the case of reacting the compound represented by-H, the order of the reaction is not particularly limited, and for example, adding a compound represented by the formula Y to an organomagnesium compound can be used ¹ Process for preparing compounds represented by formula (Y) ¹ A method of adding an organomagnesium compound to the compound represented by-H or a method of adding both of them simultaneously.

Y in the organomagnesium compound (A-1) described above ¹ The molar composition ratio c/(α+β) with respect to the whole metal atoms is preferably 0.ltoreq.c/(α+β). Ltoreq.2, more preferably 0.ltoreq.c/(α+β) < 1. By Y ¹ The molar composition ratio of the organic magnesium compound (A-1) to the titanium compound (A-2) tends to be 2 or less relative to the total metal atoms, and the reactivity with the titanium compound (A-2) tends to be improved.

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

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) … … (2)

In the above formula (2), d is preferably 0 to 1, more preferably 0.

In addition, R is as defined by the above formula (2) ⁷ The hydrocarbon group represented is not particularly limited, and examples thereof include: aliphatic hydrocarbon groups such as methyl, ethyl, propyl, butyl, pentyl, hexyl, 2-ethylhexyl, heptyl, octyl, decyl, and allyl; alicyclic hydrocarbon groups such as cyclohexyl, 2-methylcyclohexyl, cyclopentyl and the like; phenyl, naphthyl, and the likeAromatic hydrocarbon groups, and the like. Aliphatic hydrocarbon groups are particularly preferred.

As represented by X ¹ Examples of the halogen atom include: chlorine atom, bromine atom, iodine atom. Chlorine atoms are particularly preferred. The titanium compound (A-2) is particularly preferably titanium tetrachloride. In this embodiment, two or more compounds selected from the above may be used in combination.

Next, the reaction of the organomagnesium compound (A-1) with the titanium compound (A-2) will be described.

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

The reaction temperature is not particularly limited, and is preferably in the range of-80℃to 150℃and more preferably in the range of-40℃to 100 ℃.

The order of adding the organomagnesium compound (A-1) and the titanium compound (A-2) is not particularly limited, and any one of the method of adding the organomagnesium compound (A-1) after adding the organomagnesium compound (A-1), the method of adding the titanium compound (A-2) after adding the titanium compound (A-1) and the method of adding the organomagnesium compound (A-1) and the titanium compound (A-2) at the same time may be used, and the method of adding the organomagnesium compound (A-1) and the titanium compound (A-2) at the same time is preferable. In the present embodiment, the solid catalyst component [ a ] obtained by the above reaction is used in the form of a slurry solution obtained by using an inert hydrocarbon solvent.

As another example of the Ziegler-Natta catalyst component used in the present embodiment, a catalyst for olefin polymerization comprising a solid catalyst component [ C ] produced by supporting an organomagnesium compound (C-4) soluble in an inert hydrocarbon solvent represented by the following formula (5) and a titanium compound (C-5) represented by the following formula (6) on a support (C-3) produced by reacting an organomagnesium compound (C-1) soluble in an inert hydrocarbon solvent represented by the following formula (3) with a chlorinating agent (C-2) represented by the following formula (4) and an organometallic compound component [ B ] is preferable.

(C-1)：(M ² ) _γ (Mg) _δ (R ⁸ ) _e (R ⁹ ) _f (OR ¹⁰ ) _g … … (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 of elements, R ⁸ 、R ⁹ And R is ¹⁰ Each is a hydrocarbon group having 1 to 20 carbon atoms, and γ, δ, e, f, and g are real numbers satisfying the following relationship. 0.ltoreq.gamma.0.ltoreq.delta.0.ltoreq.e.0.ltoreq.f.ltoreq.0.ltoreq.g, 0.ltoreq.e+f, 0.ltoreq.g/(γ+delta). Ltoreq.2, kγ+2δ=e+f+g (where k represents M) ² Is not limited, and is not limited. ))

(C-2)：H _h SiCl _i R ¹¹ _(4-(h+i)) … … (4)

(in formula 4, R ¹¹ Is a hydrocarbon group having 1 to 12 carbon atoms, and h and i are real numbers satisfying the following relationship. H is more than 0 and less than 0, i is more than 0 and less than or equal to 4, and h+i is more than 0 and less than or equal to 4)

(C-4)：(M ¹ ) _α (Mg) _β (R ² ) _a (R ³ ) _b Y ¹ _c … … (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 of elements, R ² And R is ³ Is a hydrocarbon group having 2 to 20 carbon atoms, Y ¹ Is hydrocarbyloxy, siloxy, allyloxy, amino, amido, -n=c-R ⁴ ,R ⁵ 、-SR ⁶ (herein, R ⁴ 、R ⁵ And R is ⁶ Represents a hydrocarbon group having 1 to 20 carbon atoms. In the case of c being 2, Y ¹ May be different from each other), and the β -keto acid residues, α, β, a, b, and c are real numbers satisfying the following relationship. 0.ltoreq.α, 0.ltoreq.β, 0.ltoreq.a, 0.ltoreq.b, 0.ltoreq.c, 0.ltoreq.a+b, 0.ltoreq.c/(α+β) ltoreq.2, nα+2β=a+b+c (where n represents M) ¹ Is not limited, and is not limited. ))

(C-5)：Ti(OR ⁷ ) _d X ¹ _(4-d) … … (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, X ¹ Is a halogen atom. )

First, the organomagnesium compound (C-1) will be described. The organomagnesium compound (C-1) is represented in the form of an organomagnesium complex that is soluble in an inert hydrocarbon solvent, but contains all of the dialkylmagnesium compound and the complex of this compound with other metal compounds. The relation kγ+2δ=e+f+g of the symbols γ, δ, e, f, and g of formula 3 represents the valency of the metal atom and the stoichiometry of the substituent.

In the above formula 3, R is as follows ⁸ ～R ⁹ The hydrocarbyl group denoted by the term "hydrocarbyl" is not particularly limited, and may be, for example, an alkyl group, a cycloalkyl group, or an aryl group, respectively, and specifically, may be exemplified by: methyl, ethyl, propyl, butyl, pentyl, hexyl, octyl, decyl, cyclohexyl, phenyl, and the like. Among them, R is preferable ⁸ And R is ⁹ Each is an alkyl group. In the case of alpha > 0, as metal atom M ² Metal atoms belonging to the group consisting of group 12, group 13 and group 14 of the periodic table may be used, and examples thereof include: zinc, boron, aluminum, etc. Aluminum and zinc are particularly preferred.

For magnesium relative to metal atom M ² The ratio δ/γ is not particularly limited, but is preferably 0.1 to 30, more preferably 0.5 to 10. In addition, in the case of using a predetermined organomagnesium compound having γ=0, for example, in R ⁸ In the case of 1-methylpropyl group, etc., the compound is soluble in an inert hydrocarbon solvent, and preferable results can be obtained in the present embodiment.

In the above (formula 3), R in the case where γ=0 is recommended ⁸ 、R ⁹ Any one of the three groups (1), group (2) and group (3) shown below.

Group (1): r is R ⁸ And R is ⁹ At least one of them is a secondary or tertiary alkyl group having 4 or more and 6 or less carbon atoms, preferably R ⁸ And R is ⁹ The number of carbon atoms of (C) is 4 to 6, and R ⁸ And R is ⁹ At least one of which is a secondary or tertiary alkyl group.

Group (2): r is R ⁸ And R is ⁹ Is alkyl having different carbon numbers, 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.

Group (3): r is R ⁸ And R is ⁹ At least one of them is a hydrocarbon group having 6 or more carbon atoms, preferably R ⁸ And R is ⁹ The sum of the carbon atoms contained in the above is an alkyl group of 12 or more.

These groups are specifically shown below.

As the secondary alkyl group or tertiary alkyl group having 4 or more and 6 or less carbon atoms in the group (1), for example, there may be used: 1-methylpropyl group, 2-methylpropyl group, 1-dimethylethyl group, 2-methylbutyl group, 2-ethylpropyl group, 2-dimethylpropyl group, 2-methylpentyl group, 2-ethylbutyl group, 2-dimethylbutyl group, 2-methyl-2-ethylpropyl group and the like. 1-methylpropyl is particularly preferred.

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

The hydrocarbon group having 6 or more carbon atoms in group (3) is not particularly limited, and examples thereof include: hexyl, heptyl, octyl, nonyl, decyl, phenyl, 2-naphthyl and the like. Among the hydrocarbon groups, alkyl groups are preferable, and among the alkyl groups, hexyl groups and octyl groups are particularly preferable.

In general, when the number of carbon atoms contained in an alkyl group increases, there is a tendency that the carbon atoms are easily dissolved in an inert hydrocarbon solvent, and there is a tendency that the viscosity of the solution becomes high. Thus, in operation, it is preferable to use an appropriately long chain alkyl group. The organomagnesium compound is used in the form of an inert hydrocarbon solution, and even if a small amount of a lewis basic compound such as an ether, an ester, or an amine is contained or remained in the solution, the organomagnesium compound can be used without any problem.

Next, the hydrocarbyloxy group (OR) in the above formula (3) ¹⁰ ) An explanation is given.

As represented by R ¹⁰ The hydrocarbyl group denoted by "C1" or "C12" is preferably an alkyl group or an aryl group, and particularly preferably an alkyl group or an aryl group having 3 to 10 carbon atoms. As R ¹⁰ There are no particular restrictions, and examples include: methyl, ethyl, propyl, 1-methylethyl, butyl, 1-methylpropyl, 1-dimethylethyl, pentyl, hexyl, 2-methylpentyl, 2-ethylbutyl, 2-ethylpentyl, 2-ethylhexyl, 2-ethyl-4-methylpentyl, 2-propylheptyl, 2-ethyl-5-methyloctyl, octyl, nonyl, decyl, phenyl, naphthyl and the like. Butyl, 1-methylpropyl, 2-methylpentyl and 2-ethylhexyl are particularly preferred.

The method for synthesizing the organomagnesium compound (C-1) is not particularly limited, and the following method is preferred: to the formula R ⁸ MgX ¹ And R is ⁸ Mg(R ⁸ X is as defined above ¹ Is a halogen atom) and are of the group consisting of the organomagnesium compounds of the formula M ² R ⁹ _k And M ² R ⁹ _(k-1) H(M ² 、R ⁹ And k is the meaning given above) in an inert hydrocarbon solvent at a temperature of from 25 ℃ to 150 ℃ and optionally followed by reacting the organometallic compound with a catalyst having a group consisting of R ⁹ (R ⁹ An alcohol of a hydrocarbon group represented by the aforementioned meaning) or an alcohol having a hydrocarbon group represented by R, which is soluble in an inert hydrocarbon solvent ⁹ The hydrocarbyloxy magnesium compound and/or hydrocarbyloxy aluminum compound of the indicated hydrocarbyl group.

In the case of reacting an organomagnesium compound soluble in an inert hydrocarbon solvent with an alcohol, the order of the reaction is not particularly limited, and any one of a method of adding an alcohol to an organomagnesium compound, a method of adding an organomagnesium compound to an alcohol, and a method of adding both of them may be used.

The reaction ratio of the organomagnesium compound soluble in the inert hydrocarbon solvent to the alcohol is not particularly limited, and the molar composition ratio g/(γ+δ) of the hydrocarbyloxy group in the resulting hydrocarbyloxy-containing organomagnesium compound to all metal atoms is preferably 0.ltoreq.g/(γ+δ). Ltoreq.2, more preferably 0.ltoreq.g/(γ+δ) < 1.

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

(C-2)：H _h SiCl _i R ¹¹ _(4-(h+i)) … … (4)

In the above formula (4), R is as follows ¹¹ The hydrocarbon group represented is not particularly limited, and examples thereof include aliphatic hydrocarbon groups, alicyclic hydrocarbon groups, and aromatic hydrocarbon groups, and specifically, examples thereof include: methyl, ethyl, propyl, 1-methylethyl, butyl, pentyl, hexyl, octyl, decyl, cyclohexyl, phenyl, and the like. Among them, an alkyl group having 1 to 10 carbon atoms is preferable, and an alkyl group having 1 to 3 carbon atoms such as a methyl group, an ethyl group, a propyl group, and a 1-methylethyl group is more preferable. In addition, h and i are numbers satisfying the relationship of h+i.ltoreq.4 and larger than 0, and i is preferably 2 or more and 3 or less.

These compounds are not particularly limited, and examples thereof include: 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 Etc. Silicon chloride compounds comprising these compounds or a mixture of two or more selected from these compounds may be used. Among them, HSiCl is preferable ₃ 、HSiCl ₂ CH ₃ 、HSiCl(CH ₃ ) ₂ 、HSiCl ₂ (C ₃ H ₇ ) More preferably HSiCl ₃ 、HSiCl ₂ CH ₃ 。

Next, the reaction of the organomagnesium compound (C-1) with the chlorinating agent (C-2) will be described. In the reaction, it is preferable to use chlorinated hydrocarbons such as inert hydrocarbon solvents, 1, 2-dichloroethane, o-dichlorobenzene, and methylene chloride in advance; the chlorinating agent (C-2) is diluted with an ether medium such as diethyl ether or tetrahydrofuran or a mixture thereof. Among them, inert hydrocarbon solvents are more preferable from the viewpoint of the performance of the catalyst.

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

The reaction method of the organomagnesium compound (C-1) and the chlorinating agent (C-2) is not particularly limited, and any of a method of simultaneously adding the organomagnesium compound (C-1) and the chlorinating agent (C-2) while simultaneously introducing them into the reactor, a method of introducing the organomagnesium compound (C-1) into the reactor after the chlorinating agent (C-2) is previously added into the reactor, or a method of introducing the chlorinating agent (C-2) into the reactor after the organomagnesium compound (C-1) is previously added into the reactor may be used. Among them, a method of introducing the organomagnesium compound (C-1) into the reactor after adding the chlorinating agent (C-2) into the reactor in advance is preferable. The carrier (C-3) obtained by the above reaction is preferably separated by filtration or decantation, and then sufficiently washed with an inert hydrocarbon solvent to remove unreacted materials, byproducts, or the like.

The reaction temperature of the organomagnesium compound (C-1) and the chlorinating agent (C-2) is not particularly limited, but is preferably 25℃or more and 150℃or less, more preferably 30℃or more and 120℃or less, and still more preferably 40℃or more and 100℃or less.

In the method of adding the organomagnesium compound (C-1) and the chlorinating agent (C-2) simultaneously while introducing them into the reactor and reacting them, it is preferable to adjust the temperature of the reactor to a prescribed temperature in advance and to adjust the temperature in the reactor to a prescribed temperature while simultaneously adding them, thereby adjusting the reaction temperature to a prescribed temperature. In the method of introducing the organomagnesium compound (C-1) into the reactor after the chlorinating agent (C-2) is previously added to the reactor, it is preferable to adjust the temperature of the reactor to which the chlorinating agent (C-2) is added to a prescribed temperature and to adjust the temperature in the reactor to the prescribed temperature while introducing the organomagnesium compound into the reactor, thereby adjusting the reaction temperature to the prescribed temperature. In the method of introducing the chlorinating agent (C-2) into the reactor after the organomagnesium compound (C-1) is previously introduced into the reactor, it is preferable to adjust the temperature of the reactor to which the organomagnesium compound (C-1) is added to a prescribed temperature and to adjust the temperature inside the reactor to the prescribed temperature while introducing the chlorinating agent (C-2) into the reactor, thereby adjusting the reaction temperature to the prescribed temperature.

Next, the organomagnesium compound (C-4) will be described. As (C-4), a compound represented by the above formula (5) is preferable.

(C-4)：(M ¹ ) _α (Mg) _β (R ² ) _a (R ³ ) _b Y ¹ _c … … (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 of elements, R ² And R is ³ Is a hydrocarbon group having 2 to 20 carbon atoms, Y ¹ Is hydrocarbyloxy, siloxy, allyloxy, amino, amido, -n=c-R ⁴ ,R ⁵ 、-SR ⁶ (herein, R ⁴ 、R ⁵ And R is ⁶ Represents a hydrocarbon group having 1 to 20 carbon atoms. In the case of c being 2, Y ¹ May be different from each other), and the β -keto acid residues, α, β, a, b, and c are real numbers satisfying the following relationship. 0.ltoreq.α, 0.ltoreq.β, 0.ltoreq.a, 0.ltoreq.b, 0.ltoreq.a+b, 0.ltoreq.c/(α+β) ltoreq.2, nα+2β=a+b+c (inWhere n represents M ¹ Is not limited, and is not limited. ))

The amount of the organomagnesium compound (C-4) used is preferably 0.1 to 10, more preferably 0.5 to 5, in terms of the molar ratio of the magnesium atom contained in (C-4) to the titanium atom contained in the titanium compound (C-5).

The reaction temperature of the organomagnesium compound (C-4) and the titanium compound (C-5) is not particularly limited, but is preferably in the range of-80℃to 150℃and more preferably in the range of-40℃to 100 ℃.

The concentration of the organomagnesium compound (C-4) is not particularly limited, but the concentration of the organomagnesium compound (C-4) is preferably 0.1 mol/L or more and 2 mol/L or less, more preferably 0.5 mol/L or more and 1.5 mol/L or less, based on the magnesium atom contained in the organomagnesium compound (C-4). In the dilution of the organomagnesium compound (C-4), an inert hydrocarbon solvent is preferably used.

The order of adding the organomagnesium compound (C-4) and the titanium compound (C-5) to the support (C-3) is not particularly limited, and any one of the methods of adding the titanium compound (C-5) after the addition of the organomagnesium compound (C-4), adding the organomagnesium compound (C-4) after the addition of the titanium compound (C-5), and simultaneously adding the organomagnesium compound (C-4) and the titanium compound (C-5) may be used. Among them, a method of adding the organomagnesium compound (C-4) and the titanium compound (C-5) at the same time is preferable. The reaction of the organomagnesium compound (C-4) with the titanium compound (C-5) is carried out in an inert hydrocarbon solvent, preferably an aliphatic hydrocarbon solvent such as hexane or heptane is used. The catalyst thus obtained is used in the form of a slurry solution obtained using an inert hydrocarbon solvent.

Next, the titanium compound (C-5) will be described. In the present embodiment, (C-5) is the titanium compound represented by the above formula (6).

(C-5)：Ti(OR ⁷ ) _d X ¹ _(4-d) … … (6)

In the above formula (6), R is ⁷ The hydrocarbon group represented is not particularly limited, and examples thereof include: aliphatic hydrocarbon groups such as methyl, ethyl, propyl, butyl, pentyl, hexyl, 2-ethylhexyl, heptyl, octyl, decyl, and allyl; alicyclic hydrocarbon groups such as cyclohexyl, 2-methylcyclohexyl, cyclopentyl and the like; aromatic hydrocarbon groups such as phenyl and naphthyl. Among them, aliphatic hydrocarbon groups are preferable. As represented by X ¹ The halogen atom represented is not particularly limited, and examples thereof include: chlorine atom, bromine atom, iodine atom. Among them, a chlorine atom is preferable. The titanium compound (C-5) selected from the above may be used singly or in combination of two or more.

The amount of the titanium compound (C-5) to be used is not particularly limited, but is preferably 0.01 to 20, more preferably 0.05 to 10, in terms of the molar ratio of the titanium atom contained in the titanium compound (C-5) to the magnesium atom contained in the carrier (C-3).

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

In the present embodiment, the method of supporting the titanium compound (C-5) on the carrier (C-3) is not particularly limited, and a method of reacting an excessive amount of the titanium compound (C-5) relative to the carrier (C-3), a method of efficiently supporting the titanium compound (C-5) by using the third component, and a method of supporting by reacting the titanium compound (C-5) with the organomagnesium compound (C-4) is preferably used.

Next, the organometallic compound component [ B ] used in the present embodiment will be described. The solid catalyst component used in the present embodiment is combined with the organometallic compound component [ B ] to form a highly active polymerization catalyst. The organometallic compound component [ B ] is sometimes also referred to as "cocatalyst". The organometallic compound component [ B ] is preferably a compound containing a metal belonging to the group consisting of groups 1, 2, 12 and 13 of the periodic table, and particularly preferably an organoaluminum compound and/or an organomagnesium compound.

As the organoaluminum compound used as the above-mentioned organometallic compound component [ B ], a compound represented by the following formula (7) is preferably used singly or in combination.

AlR ¹² _j Z ¹ _(3-j) … … (7)

(in formula 7, R ¹² Is a hydrocarbon group having 1 to 20 carbon atoms, Z ¹ J is a group selected from the group consisting of a hydrogen atom, a halogen atom, a hydrocarbyloxy group, an allyloxy group, and a siloxy group, and is a number of 2 to 3. )

In the above formula (7), R is as follows ¹² The hydrocarbon group having 1 to 20 carbon atoms is not particularly limited, and includes, for example, aliphatic hydrocarbon groups, aromatic hydrocarbon groups, and alicyclic hydrocarbon groups. Specific examples of the organoaluminum compound include trialkylaluminums such as trimethylaluminum, triethylaluminum, tripropylaluminum, tributylaluminum, tris (2-methylpropylaluminum (or triisobutylaluminum), tripentylaluminum, tris (3-methylbutylaluminum), trihexylaluminum, trioctylaluminum, and tridecylaluminum; aluminum halide compounds such as diethylaluminum chloride, ethylaluminum dichloride, di (2-methylpropyl) aluminum chloride, ethylaluminum sesquichloride, diethylaluminum bromide, etc.; aluminum alkoxides such as diethylaluminum ethoxide and di (2-methylpropyl) aluminum butoxide; silicoxyaluminum compounds such as dimethylsiloxy dimethylaluminum, ethylmethylhydrosilyloxydiethylaluminum, ethyldimethylsilyloxydiethylaluminum and the like; and mixtures thereof. Trialkylaluminum compounds are particularly preferred.

As the organomagnesium compound used as the organometallic compound component [ B ], an organomagnesium compound soluble in an inert hydrocarbon solvent represented by the above formula (3) is preferable.

(M ² ) _γ (Mg) _δ (R ⁸ ) _e (R ⁹ ) _f (OR ¹⁰ ) _g … … (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 of elements, R ⁸ 、R ⁹ And R is ¹⁰ Each is a hydrocarbon group having 1 to 20 carbon atoms, and γ, δ, e, f, and g are real numbers satisfying the following relationship. Gamma is more than or equal to 0 and less than or equal to 0, delta is more than or equal to 0 and less than or equal to e, f is more than or equal to 0 and less than or equal to g,0 < e+f, 0.ltoreq.g/(γ+δ). Ltoreq.2, kγ+2δ=e+f+g (where k represents M) ² Is not limited, and is not limited. ))

The organomagnesium compound is represented in the form of an organomagnesium complex that is soluble in an inert hydrocarbon solvent, but includes both the dialkylmagnesium compound and the complexes of the compound with other metal compounds. Regarding γ, δ, e, f, g, M ² 、R ⁸ 、R ⁹ ，OR ¹⁰ As already explained, the organomagnesium compound preferably has high solubility in an inert hydrocarbon solvent, so delta/gamma is preferably in the range of 0.5 to 10 inclusive, and M is more preferably ² Is an aluminum compound.

The combination ratio of the solid catalyst component and the organometallic compound component [ B ] is not particularly limited, but the organometallic compound component [ B ] is preferably 1 mmol or more and 3,000 mmol or less with respect to 1g of the solid catalyst component.

[ polymerization conditions ]

In the production of the polyethylene powder of the present embodiment, the polymerization method is not particularly limited, and it is preferable to (co) polymerize ethylene alone or a monomer containing ethylene using a slurry polymerization method from the viewpoint of being able to effectively remove the heat of polymerization. It is preferable to use a multistage polymerization in which polymerization is carried out in two or more stages having different reaction conditions, or a parallel polymerization in which polymerization is carried out in two or more reactors having different reaction conditions and these are mixed.

Inert hydrocarbon media may be used as the medium in the slurry polymerization process.

The inert hydrocarbon medium is not particularly limited, and examples thereof include: aliphatic hydrocarbons such as propane, butane, isobutane, pentane, isopentane, hexane, heptane, octane, decane, dodecane, and kerosene; alicyclic hydrocarbons such as cyclopentane, cyclohexane, and methylcyclopentane; aromatic hydrocarbons such as benzene, toluene, and xylene; halogenated hydrocarbons such as ethyl chloride, chlorobenzene, and methylene chloride; and mixtures thereof, and the like.

In the polymerization step of the polyethylene powder, an inert hydrocarbon medium having 6 to 10 carbon atoms is preferably used. The carbon number of 6 or more allows the low-molecular-weight component generated by side reaction during polymerization of ethylene or degradation of polyethylene to be dissolved relatively easily, and can be removed easily in the step of separating polyethylene from the polymerization medium. The carbon number of 10 or less tends to inhibit adhesion of polyethylene powder to the reaction tank, and the like, and thus can be operated industrially stably.

The polymerization reaction may be carried out in any of a batch type, a semi-continuous type and a continuous type, but it is preferable to carry out the polymerization in a continuous type.

By continuously supplying ethylene gas, solvent, catalyst, etc. into the polymerization system and continuously discharging the ethylene gas, solvent, catalyst, etc. together with the produced polyethylene, a local high temperature state due to rapid ethylene reaction can be suppressed, and the polymerization system can be more stable. When ethylene is reacted in a uniform state in the system, the formation of branches, double bonds, and the like in the polymer chain can be suppressed, and the polyethylene is less likely to be reduced in molecular weight and crosslinked, so that melting of the ultra-high molecular weight polyethylene powder or the remaining unmelted matter during melting is reduced, coloring can be suppressed, and problems such as a decrease in mechanical properties are less likely to occur. Thus, a more uniform continuous type within the polymerization system is preferred.

The polymerization temperature is usually 30℃to 100℃inclusive, preferably 35℃to 95℃inclusive, and more preferably 40℃to 90℃inclusive. The polymerization temperature of 30℃or higher tends to be industrially effective for production. The polymerization temperature is 100 ℃ or lower, whereby continuous and stable production tends to be possible.

The polymerization pressure is usually not less than normal pressure and not more than 5.0MPa, preferably not less than 0.1MPa and not more than 4.0MPa, more preferably not less than 0.1MPa and not more than 3.0 MPa.

In the polymerization of the polyethylene powder of the present embodiment, in the case of using a continuous two-stage polymerization in which two polymerization reactions having different reaction conditions are continuously performed, it is preferable to obtain a polyethylene having a lower molecular weight than that of the second stage in the first-stage polymerization. The molecular weight of polyethylene can be controlled by, for example, allowing hydrogen to exist in the polymerization system, changing the polymerization temperature, and the like as described in the specification of german patent application publication No. 3127133. In addition, by adding hydrogen as a chain transfer agent to the polymerization system, the molecular weight can be easily controlled within an appropriate range. When hydrogen is added to 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.

In addition, in the polymerization of the polyethylene powder of the present embodiment, in the case of using the continuous two-stage polymerization, it is preferable to rapidly carry out the polymerization reaction of the second stage. The polymerization rate of polyethylene can be controlled by increasing the amount of the above-mentioned cocatalyst, increasing the polymerization pressure, and the like.

In the polymerization of the polyethylene powder of the present embodiment, when continuous parallel polymerization in which polymerization reactions are performed in parallel in two reactors having different reaction conditions and they are mixed is used, it is preferable to polymerize the low-molecular-weight polyethylene having a large particle diameter in one polymerization reactor and to polymerize the high-molecular-weight polyethylene having a small particle diameter in the other reactor. The particle size of the polyethylene can be controlled by the polymerization pressure, the addition amount of the catalyst, and the like.

In addition, in the polymerization of the polyethylene powder of the present embodiment, when continuous parallel polymerization is used, it is preferable that the polymerization reaction be rapidly carried out when high molecular weight polyethylene having a small particle diameter is obtained by the polymerization.

In order to inhibit the adhesion of the polymer to the polymerization reactor when the polyethylene powder of the present embodiment is obtained by polymerization, antistatic agents such as Stadis450 (manufactured by the company The Associated Octel Company) (agency pellets and products) may be used. The Stadis450 may also be diluted in an inert hydrocarbon medium and added to the polymerization reactor using a pump or the like. The amount of antistatic agent such as Stadis450 is preferably in the range of 0.10ppm to 20ppm, more preferably in the range of 0.20ppm to 10ppm, relative to the amount of polyethylene produced per unit time.

In the production of the polyethylene powder of the present embodiment, the polyethylene powder is separated from the solvent. Examples of the solvent separation method include: decantation, centrifugation, filter filtration, and the like are preferable from the viewpoint of high separation efficiency of polyethylene powder from the solvent.

In the production of the polyethylene powder of the present embodiment, the catalyst used in the production process is deactivated. The method for inactivating the catalyst is not particularly limited, and it is preferable to inactivate the polyethylene powder after separating it from the solvent. By adding a chemical reagent for inactivating the catalyst after separation from the solvent, precipitation of a catalyst component or the like dissolved in the solvent can be suppressed. Examples of chemical agents for deactivating the catalyst system include: oxygen, water, alcohols, glycols, phenols, carbon monoxide, carbon dioxide, ethers, carbonyl compounds, alkynes, and the like, but are not limited thereto.

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

The drying temperature is preferably 70 ℃ to 120 ℃, more preferably 75 ℃ to 115 ℃, still more preferably 80 ℃ to 110 ℃.

The drying temperature is 70 ℃ or higher, so that efficient drying tends to be possible. The drying temperature of 120 ℃ or lower tends to dry the polyethylene powder while suppressing aggregation and thermal degradation of the polyethylene powder.

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

The cooling temperature is 0 ℃ or lower, more preferably-10 ℃ or lower. The cooling temperature of 0 ℃ or lower tends to more significantly exhibit the structure peculiar to the polyethylene powder of the present embodiment, in which the surface roughness of the particles becomes rough as the particle size of the powder becomes smaller.

The polyethylene powder according to the present embodiment may be directly fed into various molding machines for molding, or may be mixed with an organic peroxide and then fed into various molding machines for molding.

[ organic peroxide ]

The organic peroxide (organic peroxide crosslinking agent) that can be used in molding the polyethylene powder of the present embodiment is not particularly limited as long as it is an organic substance that contributes to crosslinking of the polyethylene and has an atomic group-O-in the molecule, and examples thereof include: organic peroxides such as dialkyl peroxide, diacyl peroxide, hydroperoxide, and ketone peroxide; organic peresters such as alkyl peresters; peroxydicarbonates, and the like. The organic peroxide is not particularly limited, and specific examples thereof include: dicumyl peroxide, di-tert-butyl peroxide, 2, 5-dimethyl-2, 5-di (tert-butylperoxy) hexane, 2, 5-dimethyl-2, 5-di (tert-butylperoxy) -3-hexyne, 1, 3-bis (tert-butylperoxyisopropyl) benzene, 1-di (tert-butylperoxy) -3, 5-trimethylcyclohexane, n-butyl 4, 4-di (tert-butylperoxy) valerate, benzoyl peroxide, p-chlorobenzoyl peroxide, 2, 4-dichlorobenzoyl peroxide, tert-butyl peroxybenzoate, tert-butyl peroxyisopropyl carbonate, diacetyl peroxide, lauroyl peroxide, tert-butylcumyl peroxide, α' -di (tert-butyl peroxide) diisopropylbenzene, and the like. Among them, 2, 5-dimethyl-2, 5-di (t-butylperoxy) hexane (trade name "Perhexa25B" manufactured by Japanese fat & oil Co., ltd.), 2, 5-dimethyl-2, 5-di (t-butylperoxy) -3-hexyne (trade name "Perhexyne 25B" manufactured by Japanese fat & oil Co., ltd.), dicumyl peroxide, 1-di (t-butylperoxy) -3, 5-trimethylcyclohexane are preferable.

[ other Components ]

The polyethylene powder of the present embodiment may be used in combination with various known additives as needed. The heat stabilizer is not particularly limited, and examples thereof include: heat-resistant stabilizers such as tetrakis [ methylene (3, 5-di-t-butyl-4-hydroxy) hydrocinnamate ] methane and distearyl thiodipropionate; or weather-resistant stabilizers such as bis (2, 2', 6' -tetramethyl-4-piperidinyl) sebacate and 2- (2-hydroxy-3-t-butyl-5-methylphenyl) -5-chlorobenzotriazole. Examples of the other additives include a neutralizing agent. The neutralizing agent can be used as a chlorine scavenger, a molding processing aid, or the like contained in the polyethylene powder. The neutralizing agent is not particularly limited, and examples thereof include: stearate of alkaline earth metals such as calcium, magnesium, and barium.

The content of the additive contained in the polyethylene powder of the present embodiment can be determined as follows: the additive in the polyethylene powder was extracted by soxhlet extraction using Tetrahydrofuran (THF) for 6 hours, and the extract was separated and quantified by liquid chromatography.

The polyethylene powder of the present embodiment may be mixed with polyethylene having different intrinsic viscosity, molecular weight distribution, etc., or may be mixed with other resins such as low-density polyethylene, linear low-density polyethylene, polypropylene, polystyrene, etc.

[ molded article ]

The molded article of the present embodiment is the molded article of the polyethylene powder of the present embodiment described above.

The molded article of the present embodiment can be obtained by molding a raw material containing the polyethylene powder by various methods.

The molding method of the molded article of the present embodiment is not particularly limited, and examples thereof include press molding and extrusion molding. The method comprises the following steps: raw materials containing polyethylene powder are uniformly dispersed in a mold, heated and pressurized to be molded, and then cooled and taken out. The press-formed product can be used as a product directly, or can be finished into a final product by secondary processing such as cutting processing and slicing processing. On the other hand, in extrusion molding, a screw extruder or a ram extruder that performs extrusion by moving a piston forward and backward is preferably used. By changing the shape of the extruder outlet, molded articles having various shapes such as a flat plate, a profile, and a tube can be obtained. Further, the molded article may be finished into a final product by performing secondary processing such as cutting processing and slicing processing from a block-shaped molded article such as a round bar or a prism.

[ use ]

The molded article of the polyethylene powder of the present embodiment is not particularly limited, and can be used as a lining material for ships, frames, agricultural implements, hoppers, and silos; an ore conveying pipe; gears and bearings for machinery; a food conveying roller; a guide rail; backing material for snowboards; artificial bone, artificial joint; and the like.

The polyethylene powder of the present embodiment may be used as a microporous film, a separator for a lithium ion secondary battery or a lead acid battery, a raw material for high-strength fibers, or the like by a wet molding method using a solvent.

Examples (example)

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 examples and comparative examples were dehydrated using MS-3A (manufactured by Sho and Union Co., ltd.), and then further deoxygenated by degassing the hexane under reduced pressure using a vacuum pump, and then used separately.

[ measurement methods and conditions ]

The physical properties of the polyethylene powders of examples and comparative examples were measured by the following methods.

(1) Viscosity average molecular weight Mv

The viscosity average molecular weight Mv of the polyethylene powder obtained in examples and comparative examples was determined according to ISO1628-3 (2010) by the method shown below.

First, 20mg of polyethylene powder was weighed into a dissolution tube, the dissolution tube was subjected to nitrogen substitution, then 20mL of decalin (1 g/L of 2, 6-di-t-butyl-4-methylphenol was added) was added, and the polyethylene powder was dissolved by stirring at 150℃for 2 hours, thereby preparing sample solutions, respectively.

The drop times (ts) between the standards were measured for the obtained sample solutions in a constant temperature bath at 135℃using a Cannon-Finsk viscometer (manufactured by Chafield scientific instruments Co., ltd.: product model number-100).

Similarly, sample solutions were prepared in which the amounts of polyethylene powder were changed to 10mg, 5mg and 2mg, and the falling times (ts) between the standard lines were measured under the same conditions.

Sample solutions were prepared without adding polyethylene powder and with decalin alone as a blank, and the drop time (tb) was measured under the same conditions.

The reduced viscosity (. Eta.sp/C) of the polyethylene powder was determined from the following formula.

Eta sp/C= (ts/tb-1)/0.1 (unit: dL/g)

Next, the relationship between the concentration (C) (unit: g/dL) and the reduced viscosity (. Eta.sp/C) of the polyethylene powder was plotted, and an approximate linear equation was derived by the least square method, and extrapolated to the concentration of 0, to obtain the intrinsic viscosity (. Eta.) respectively.

Then, the viscosity average molecular weight Mv (g/mol) was calculated from the values of the intrinsic viscosity [ η ] using the following formula (mathematical formula a).

Mv＝(5.34×10 ⁴ )×[η] ^1.49 (mathematics A)

(2) Viscosity average molecular weight Mv ₇₅ And viscosity average molecular weight Mv ₁₅₀ Difference DeltaMv

The polyethylene powders were each classified by using a sieve having a mesh size of 150 μm and 75 μm in accordance with JIS Z8801 standard, and the powder on the sieve of 150 μm and the powder under the sieve of 75 μm were each separated. The viscosity average molecular weight (Mv) of the powder obtained on the 150 μm sieve was measured according to the above-mentioned measurement method (1) ₁₅₀ ) And viscosity average molecular weight (Mv) of the powder under a 75 μm sieve ₇₅ ). From the obtained viscosity average molecular weights, differences Δmv (g/mol) (=mv) were calculated, respectively ₇₅ -Mv ₁₅₀ )。

(3) Comonomer content

The comonomer content (mol%) of each polyethylene powder obtained in examples and comparative examples was used ¹³ C-NMR was measured under the following conditions, respectively.

The device comprises: AVANCEIII 500HD Prodigy (Bruker Biospin Co.)

Observation frequency: 125.77 MHz% ¹³ C)

Pulse width: 5.0 microseconds

Pulse repetition time: 5 seconds

Cumulative number of times: 10,000 times back

Measuring temperature: 120 DEG C

Reference: 29.9ppm (PE: sdelta delta)

Solvent: o-C ₆ D ₄ Cl ₂

Sample concentration: 0.1g/mL

And (3) sample tube: 5mm phi

For the measurement sample, a polyethylene powder of 60mg was added with 0.6mL o-C ₆ D ₄ Cl ₂ And the sample obtained by dissolving it while heating at 130 ℃.

(4) Average particle diameter X ₅₀

100g of polyethylene powder was weighed into 200mL plastic cups, 1g of carbon black was added, and the mixture was stirred well with a spatula. When the stirred polyethylene powder was classified by using sieves having mesh sizes of 300 μm, 212 μm, 150 μm, 106 μm, 75 μm, and 53 μm according to JIS Z8801, the mass of the polyethylene powder remaining on each sieve was integrated from the side having the smaller mesh size, and the particle diameter (sieve analysis particle diameter) at which 50 mass% was reached in the obtained integration curve (cumulative distribution on sieve) was regarded as the average particle diameter (μm).

(5) Bulk density a, tap density b, ratio a/b

Bulk density a (g/cm) was measured using a powder tester PT-X (manufactured by Mikroot Co., ltd.) as follows ³ ) And tap density b (g/cm) ³ ) Is measured.

In stainless steel 100cm ³ In a cylindrical container, a sample supply device was vibrated to cause polyethylene powder to flow down until the polyethylene powder was deposited in the container, and a doctor blade was used to scrape off excess polyethylene powder from the container, thereby preparing measurement samples, respectively, and the value obtained by measuring the measurement samples was taken as the bulk density a (g/cm ³ )。

In addition, the stainless steel is 100cm ³ The cylinder container was capped with an upper lid, and the sample supply device was vibrated to flow down polyethylene powder, and tapping was performed under conditions of a stroke length (tap height) of 18mm, a tap speed of 60 times/min, and a tap number of 180 times. Then, excess polyethylene powder on the container was scraped off with a spatula to prepare measurement samples, respectivelyThe value obtained by measuring the measurement sample was used as tap density b (g/cm ³ )。

Then, the value of the ratio a/b is obtained by multiplying the value obtained by dividing the value of the bulk density a measured as described above by the tap density b by 100.

(6) Unmelted residue in central portion of cross section of extrusion molded body

The molding process of the molded body of each polyethylene powder was performed using a single screw extruder having a screw diameter of 25mm and a screw length/screw diameter of 28. The screw was a full flight screw and the molding was carried out at a barrel temperature of 210 ℃. A mold having a length of 600mm was set at the front end of the extruder to form a 35mm square molded body. The molding was performed under the conditions that the temperature of the front stage of the mold was 180℃and the temperature of the rear stage was 40 ℃. In addition, the screw rotation speed was adjusted so that the discharge amount was 4 m/hr. The presence or absence of unmelted residue, i.e., unmelted portions, in the central portion of any cross section of the molded article produced was visually determined. When unmelted residue is generated, the determination can be made based on the white turbidity in the central portion. The decision criteria are shown below.

… … is free of unmelted residue in the central portion of any cross section

X … … with unmelted residue in the center of any cross section

(7) Impact Strength of the center portion and the end portion of the extrusion molded article

Test pieces of 120 mm.times.15 mm.times.10 mm were cut out from the center and inner side portions 3mm from the end portions of each extrusion molded body obtained by the above-described method, respectively, and impact strength was measured by the simple beam impact test according to ISO11542-2, respectively. 5 test pieces were prepared, and the average of 5 measurements was calculated. The ratio of the impact strength of the central portion to the impact strength of the end portion of the extrusion molded article was obtained by dividing the average value of the impact strength of the central portion by the average value of the impact strength of the end portion (average value of the impact strength of the central portion/average value of the impact strength of the end portion), and the judgment was made based on the following judgment criteria.

The ratio of impact strength of the central portion to the end portion of the extrusion molded body of … … is 0.9 or more

The ratio of impact strength of the central portion to the end portion of the … … extrusion molded body is 0.8 or more and less than 0.9

The ratio of impact strength of the central portion to the end portion of the x … … extrusion molded body is less than 0.8

(8) Void of pressed molded body

9kg of each polyethylene powder was put into a mold having a height of 100mm and a square of 300mm in a heated press molding machine in a natural falling manner, then the surface was uniformly flattened, compression molded for 3 hours at a set temperature of 210℃under a gauge pressure of 10MPa, and then subjected to a cooling process in which heating was stopped while maintaining the pressure, whereby press molded articles were produced, respectively. The obtained press-molded bodies were each cut at 100mm intervals, and 3 sections were each observed with a 5-fold magnifying glass. The number of void defects in the cross section of the pressed compact was counted, and the judgment was made based on the following judgment criteria.

The total number of white points of the … … cross section is 0

Is … … of a cross-section of 1

The total number of white spots of x … … cross sections is 2 or more

[ method of catalyst Synthesis ]

[ preparation of solid catalyst component [ A ]

(1) Synthesis of raw material (a-1)

1 mol/L of Mg was charged into an 8L stainless steel autoclave fully purged with nitrogen ₆ (C ₄ H ₉ ) ₁₂ Al(C ₂ H ₅ ) ₃ To the hexane solution of (1) was added dropwise 146mL of 5.47 mol/L n-butanol hexane solution over 3 hours while stirring at 50℃and, after the completion, the line was purged with 300mL hexane. Stirring was then continued at 50℃for 2 hours. After the completion of the reaction, the material cooled to room temperature was used as the starting material [ a-1]]. Raw material [ a-1]]The total concentration of magnesium and aluminum was 0.704 mol/L.

(2) Synthesis of raw Material [ a-2]

Adding into an 8L stainless steel autoclave after full nitrogen substitution1 mol/L of Mg ₆ (C ₄ H ₉ ) ₁₂ Al(C ₂ H ₅ ) ₃ 2,000mL (corresponding to 2000 mmol in terms of magnesium and aluminum), and 240mL of a hexane solution of 8.33 mol/L methyl hydrogen polysiloxane (manufactured by Xinyue chemical Co., ltd.) was fed under pressure while stirring at 80℃and stirring was continued at 80℃for 2 hours. After the completion of the reaction, the material cooled to room temperature was used as the raw material [ a-2]]. Raw material [ a-2]The total concentration of magnesium and aluminum was 0.786 mol/L.

(3) Synthesis of [ A-1] vector

1,000mL of a hexane solution of 1 mol/L hydroxytrichlorosilane was charged into an 8L stainless steel autoclave after sufficient nitrogen substitution, 1340mL of a hexane solution of an organomagnesium compound of the raw material [ a-1] was dropwise added at 65℃over 3 hours (corresponding to 943 mmol of magnesium), and the reaction was continued while stirring at 65℃for 1 hour. After completion of the reaction, the supernatant was removed, and the mixture was washed 4 times with 1,800mL of hexane to obtain [ A-1] carrier. The carrier was analyzed, and as a result, the amount of magnesium contained in each 1g of solid was 7.5 mmol.

(4) Preparation of solid catalyst component [ A ]

To 100 g of the hexane slurry 1,970mL of the above [ A-1] carrier was added 103mL of a hexane solution of 1 mol/L titanium tetrachloride and 131mL of the raw material [ a-2] over 3 hours while stirring at 10 ℃. After the addition, the reaction was continued at 10℃for 1 hour. After the completion of the reaction, the supernatant was removed, and the reaction mixture was washed with hexane 4 times, whereby unreacted raw material components were removed, 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 polymerization step, hexane, ethylene, hydrogen, a catalyst were continuously supplied to a vessel type 300L polymerization reactor (1) with a stirring device. The polymerization pressure was maintained at 0.31MPa. The polymerization temperature was maintained at 70℃by jacket cooling. Hexane was supplied at 40L/hr from the bottom of the polymerization reactor (1). Using solid catalyst components [ A ]]As catalyst, M was usedg ₆ (C ₄ H ₉ ) ₁₂ Al(C ₂ H ₅ ) ₃ As a cocatalyst. Solid catalyst component [ A ]]The cocatalyst was added at a rate of 1.5 g/hr from the middle of the liquid surface and the bottom of the polymerization reactor (1), and the cocatalyst was added at a rate of 10 mmol/hr from the middle of the liquid surface and the bottom of the polymerization reactor (1). Hydrogen was used as a molecular weight regulator, and was supplied so that the molar concentration of the hydrogen gas in the gas phase (hydrogen/(ethylene+hydrogen)) relative to the sum of ethylene and hydrogen was 4.32 mol%. Hydrogen was supplied to the gas phase section, 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 polymerization stage, the polymer slurry solution in the first polymerization reactor (1) was introduced into a flash tank having an internal volume 300L maintained at a pressure of 0.05MPa and a temperature of 70 ℃ to separate unreacted ethylene and hydrogen, and then introduced into the bottom of the second vessel type 300L polymerization reactor (2) identical to the polymerization reactor (1) by means of a slurry pump. Hexane was introduced into the slurry pump at a rate of 110L/hr. Further, ethylene and a cocatalyst are continuously supplied to the polymerization reactor (2) to carry out polymerization. The polymerization pressure was maintained at 0.99MPa and the polymerization temperature was maintained at 73 ℃. Cocatalyst Mg ₆ (C ₄ H ₉ ) ₁₂ Al(C ₂ H ₅ ) ₃ Is fed into the polymerization reactor (2) at a rate of 50 mmol/hr. Ethylene and a cocatalyst were supplied from the same location as in the polymerization reactor (1). In addition, no hydrogen was supplied during the second polymerization stage. The high molecular weight polymerization was carried out in such a manner that the ratio of the mass of the high molecular weight component produced in the second-stage polymerization reactor (2) to 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) (mass of the high molecular weight component produced in the second-stage polymerization reactor (2)/(mass of the low molecular weight component produced in the first-stage polymerization reactor (1) +mass of the high molecular weight component produced in the second-stage polymerization reactor (2)) was 0.50 The production rate was 20 kg/hr.

The resulting polymerization slurry was continuously withdrawn into a flash tank having a pressure of 0.04MPa in such a manner that the liquid level of the polymerization reactor (2) was kept constant, and unreacted ethylene was separated.

Then, the resulting polymerization slurry is continuously fed into a centrifuge in such a manner that the liquid level of the polymerization reactor (2) is kept constant, and the polymer (polyethylene powder) is separated from the other solvents and the like.

The separated polyethylene powder was stirred and dried at 110℃for 0.5 hour while blowing nitrogen. In the drying step, steam is sprayed to the polyethylene powder after polymerization, whereby deactivation of the catalyst and the cocatalyst is performed. Then, the dried polyethylene powder was stirred and nitrogen gas was blown at-10℃for 10 minutes, thereby cooling the polyethylene powder. After cooling, 500ppm of calcium stearate (manufactured by Dai chemical Co., ltd., C60) was added to the polyethylene powder after returning to the normal temperature, and the mixture was uniformly mixed using a Henschel mixer. Next, the polyethylene powder was passed through a sieve having a mesh size of 425 μm, and the powder which did not pass through the sieve was removed, thereby obtaining a polyethylene powder having a viscosity average molecular weight Mv of 193X 10 ⁴ g/mol of the polyethylene powder of example 1.

The properties of the polyethylene powder of example 1 obtained are shown in table 1.

Example 2

Polyethylene powder was produced by two-stage polymerization in the same manner as in example 1. In the first polymerization step, 1-butene was continuously fed from the bottom of the polymerization reactor (1) at 0.90 mol% relative to ethylene, the gas phase molar concentration of hydrogen relative to the sum of ethylene and hydrogen was changed to 1.40 mol%, the feeding of 1-butene was stopped in the second polymerization step, the concentration of 1-butene relative to ethylene was 0.07 mol%, the polymerization pressure was changed to 1.95MPa, and the polymerization temperature was changed to 60℃to obtain a viscosity average molecular weight Mv of 407X 10 by the same procedure as in example 1 above ⁴ Polyethylene powder of example 2 having a g/mol and comonomer content of 0.04 mol%And (3) finally, performing powder. The production rate of polyethylene in the polymerization reactor (2) was 20 kg/hr.

The properties of the polyethylene powder of example 2 obtained are shown in table 1.

Example 3

Polyethylene powder was produced by side-by-side polymerization. Hexane, ethylene, 1-butene, hydrogen and a catalyst were continuously fed into the vessel type 300L polymerization reactor (1) similar to that of the above-mentioned example 1 from the same positions as those of the above-mentioned example 2. The polymerization pressure was maintained at 0.30MPa and the polymerization temperature was maintained at 78 ℃. Polymerization in a polymerization reactor (1) was carried out in the same manner as in example 2 above, except that the flow rate of hexane was changed to 80L/hr, the supply amount of the solid catalyst component [ a ] was changed to 0.4 g/hr, the cocatalyst was changed to a mixture of triisobutylaluminum and diisobutylaluminum hydride (a mixture of 9:1 in order of mass ratio) to 5 mmol/hr, 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% with respect to ethylene. The production rate of polyethylene in the polymerization reactor (1) was 10 kg/hr.

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

Polymerization reactor (1) and polymerization reactor are operated in such a way that the liquid level of the polymerization reactor is kept constantThe polymerization syrup of the reactor (2) was continuously introduced into a stirrer having an internal volume of 300L and a pressure of 0.04MPa, and the polymerization syrup was stirred while unreacted ethylene and hydrogen were separated. Then, by the same operation as in example 1, a viscosity average molecular weight Mv of 415X 10 was obtained ⁴ The polyethylene powder of example 3 having a g/mol and comonomer content of 0.04 mol%. The production rate of polyethylene in the polymerization reactor (1) and the polymerization reactor (2) was 20 kg/hr in total.

The properties of the polyethylene powder of example 3 obtained are shown in table 1.

Example 4

Polyethylene powder was produced by parallel polymerization in the same manner as in example 3. Polymerization in the polymerization reactor (1) was carried out in the same manner as in example 3 above, except that the polymerization pressure in the polymerization reactor (1) was changed to 0.31MPa, the supply amount of the solid catalyst component [ A ] was changed to 0.3 g/hr, the supply amount of the cocatalyst was changed to 4 mmol/hr, the gas phase molar concentration of hydrogen was changed to 0.64 mol%, and 1-butene was not added. The production rate of polyethylene in the polymerization reactor (1) was 5 kg/hr.

Polymerization in the polymerization reactor (2) was carried out in the same manner as in example 3 above, except that the polymerization pressure in the polymerization reactor (2) was changed to 2.30MPa, the polymerization temperature was changed to 50℃and the supply amount of the solid catalyst component [ A ] was changed to 1.1 g/hr and the concentration of 1-butene was changed to 0.60 mol%. The production rate of polyethylene in the polymerization reactor (2) was 10 kg/hr.

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

The properties of the polyethylene powder of example 4 obtained are shown in table 1.

Example 5

Polyethylene powder was produced by two-stage polymerization in the same manner as in example 2. Polymerization reactions in the polymerization reactors (1) and (2) were carried out in the same manner as in example 2 above except that the polymerization pressure in the second polymerization step was changed to 0.65MPa and the supply amount of the cocatalyst was changed to 10 mmol/hr.

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

The properties of the polyethylene powder of example 5 obtained are shown in table 1.

Example 6

Polyethylene powder was produced by two-stage polymerization in the same manner as in example 2.

The procedure of example 2 was repeated except that nitrogen gas at-10℃was not blown into the dried powder for 10 minutes after the polymerization reaction in the polymerization reactor (1) and the polymerization reactor (2).

Then, by the same operation as in example 2, a viscosity average molecular weight Mv of 403X 10 was obtained ⁴ The polyethylene powder of example 6 having a g/mol and comonomer content of 0.04 mol%. The production rate of polyethylene in the polymerization reactor (2) was 20 kg/hr.

The properties of the polyethylene powder of example 6 obtained are shown in table 1.

Comparative example 1

Polyethylene powder was produced by one-step polymerization. Hexane, ethylene, hydrogen and a catalyst were continuously fed from the same positions as in example 1 to the vessel-type 300L polymerization reactor (1) as in example 1. The polymerization pressure was maintained at 0.30MPa and the polymerization temperature was maintained at 75 ℃. Polymerization in the polymerization reactor (1) was carried out in the same manner as in example 1 above, except that the flow rate of hexane was changed to 80L/hr, the supply amount of the solid catalyst component [ A ] was changed to 0.3 g/hr, the mixture of triisobutylaluminum and diisobutylaluminum hydride as cocatalysts (a mixture of 9:1 in order by mass ratio) was changed to 5 mmol/hr, and the gas-phase molar concentration of hydrogen was changed to 0.27 mol%. The production rate of polyethylene in the polymerization reactor (1) was 10 kg/hr.

Then, the same operation as in example 1 was performed except that nitrogen gas at-10℃was not blown to the dried powder for 10 minutes, whereby a powder having a viscosity average molecular weight Mv of 330X 10 was obtained ⁴ g/mol of the polyethylene powder of comparative example 1.

The properties of the polyethylene powder of comparative example 1 obtained are shown in table 1.

Comparative example 2

Polyethylene powder was produced by two-stage polymerization in the same manner as in example 2. A viscosity average molecular weight Mv of 411X 10 was obtained in the same manner as in example 2 above except that the polymerization pressure in the second polymerization step was changed to 0.65MPa, the supply amount of the cocatalyst was changed to 10 mmol/hr, and nitrogen gas at-10℃was not blown into the dried powder for 10 minutes ⁴ The polyethylene powder of comparative example 2 having g/mol and a comonomer content of 0.04 mol%. The production rate of polyethylene in the polymerization reactor (2) was 20 kg/hr.

The properties of the polyethylene powder of comparative example 2 obtained are shown in table 1.

Comparative example 3

Polyethylene powder was produced by two-stage polymerization in the same manner as in example 1. In comparative example 3, a high molecular weight component was obtained by polymerization in the first polymerization stage, and a low molecular weight component was obtained by polymerization in the second polymerization stage. In the first polymerization step, the polymerization pressure was changed to 0.27MPa, the polymerization temperature was changed to 74℃and in the second polymerization step, the polymerization pressure was changed to 0.56MPa, the polymerization temperature was changed to 78℃and the cocatalyst supply was changed to 10 mmol/hr, 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%, and nitrogen gas at-10℃was not blown to the dried powder for 10 minutes, but the same procedure as in example 1 was followed A viscosity average molecular weight Mv of 393X 10 was obtained ⁴ The polyethylene powder of comparative example 3 having g/mol and comonomer content of 0.05 mol%. The production rate of polyethylene in the polymerization reactor (2) was 20 kg/hr.

The properties of the polyethylene powder of comparative example 3 obtained are shown in table 1.

Comparative example 4

Polyethylene powder was produced by two-stage polymerization in the same manner as in example 1. In comparative example 4, the high molecular weight component was obtained by polymerization in the first polymerization stage and the low molecular weight component was obtained by polymerization in the second polymerization stage, similarly to comparative example 3. In the first polymerization step, the polymerization pressure was changed to 0.27MPa, the polymerization temperature was changed to 74℃and in the second polymerization step, the polymerization pressure was changed to 1.68MPa, the polymerization temperature was changed to 78℃and the cocatalyst supply was changed to 50 mM/hr, 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%, except that the hydrogen was supplied at a gas phase molar concentration of 0.20 mol%, and a viscosity average molecular weight Mv of 391X 10 was obtained by the same operation as in example 1 ⁴ The polyethylene powder of comparative example 4 having g/mol and comonomer content of 0.06 mol%. The production rate of polyethylene in the polymerization reactor (2) was 20 kg/hr.

The properties of the polyethylene powder of comparative example 4 obtained are shown in table 1.

Industrial applicability

The polyethylene powder of the present invention is industrially useful as a raw material for various molded articles, microporous films, separators, and high-strength fibers.

Claims

1. A polyethylene powder, wherein,

the polyethyleneThe powder has an average particle diameter X of 50-200 mu m based on the accumulated mass ₅₀ ，

Viscosity average molecular weight Mv of undersize powder when classifying the polyethylene powder with a sieve having a mesh size of 75 μm ₇₅ (g/mol) and viscosity average molecular weight Mv of the on-screen powder when classifying the polyethylene powder with a sieve having a mesh size of 150 μm ₁₅₀ (g/mol) difference Δmv (here, Δmv=mv ₇₅ -Mv ₁₅₀ ) Greater than 0 (g/mol) and equal to or less than 4,000,000 (g/mol), and

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

3. Polyethylene powder according to claim 1 or 2, wherein the difference Δmv is greater than 10 (g/mol) and less than or equal to 3,000,000 (g/mol).

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

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

6. An extrusion molded article obtained by extrusion molding a raw material comprising the polyethylene powder according to any one of claims 1 to 3.

7. A microporous membrane, wherein the microporous membrane uses the polyethylene powder of claim 1 or 2.

8. A high strength fiber, wherein the high strength fiber uses the polyethylene powder of claim 1 or 2.