JP6393672B2 - Polyethylene powder and fiber - Google Patents

Description

  The present invention relates to polyethylene powder and fibers.

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

  High molecular weight polyethylene powder is generally difficult to process by injection molding or the like due to its high viscosity, and is therefore often dissolved in a solvent and molded. For example, when processing into fibers, ultrahigh molecular weight polyethylene is dissolved in a solvent, and the resulting diluted solution is spun and stretched. Thereby, high-strength fibers having a high elastic modulus and tensile strength and highly oriented are obtained.

  Further, a technique has been disclosed in which high molecular weight polyethylene reduces the number of defects generated during molding and makes the structure uniform. For example, Patent Document 1 discloses that defects in the crystal structure of polyethylene can be reduced by optimizing the solvent weight loss rate during solvent removal in the spinning process. Patent Document 2 discloses that by adding a poor solvent as a solvent, the spread of polyethylene molecular chains is suppressed, the entanglement of molecular chains causing defects is reduced, and the heterogeneous structure is suppressed. Furthermore, Patent Document 3 discloses a uniform crystal structure by making the solvent evaporation rate uniform when discharging the polyethylene solution from the nozzle and further reducing the crystal size by cooling the gel discharged from the spinneret uniformly. It is disclosed that a molded body having the following can be obtained.

  In addition, Patent Document 4 discloses that polyethylene is uniformly dissolved by using a paraffin wax instead of a liquid solvent. Patent Document 5 discloses that a dialkyl ketone is used as an additive to suppress the formation of a highly viscous gel substance due to non-uniform dissolution. In addition, although these patent documents 1-5 have description regarding the characteristic of a polyethylene solution, there is no description which improves the characteristic of the polyethylene powder which is a raw material.

Japanese Patent No. 5327488 JP 2007-297863 A Japanese Patent No. 3666635 Japanese Patent Publication No. 7-29372 JP 2011-241485 A

  However, polyethylene using conventional polyethylene powder is said to increase the load when forming polyethylene to increase the tensile strength, and the load applied when forming into fibers increases and breaks (yarn breakage). There's a problem. On the other hand, in the step of dissolving polyethylene in a solvent, if undissolved polyethylene powder remains as particles, problems such as yarn breakage during spinning after forming and partial reduction in fiber tensile strength may occur. For this reason, in order to improve the tensile strength and elastic modulus, it is important to obtain a molded product with few defects due to uniform dissolution in the step of dissolving polyethylene in a solvent.

  Then, an object of this invention is to provide the polyethylene powder which melt | dissolves in a solvent rapidly and has few generation | occurrence | production of an undissolved substance.

  As a result of diligent research to solve the above-described problems of the prior art, the inventor has a specific surface area, a pore volume, a half-value width of a melting endothermic peak, a viscosity average molecular weight, and an average particle diameter in a predetermined range. The present inventors have found that polyethylene powder dissolves quickly in a solvent and generates less undissolved material, and has led to the present invention.

That is, the present invention is as follows.
[1]
Specific surface area determined by BET method, and a 0.20 m ² / g or more 0.80 m ² / g or less,
The pore volume determined by the mercury intrusion method is 0.95 mL / g or less,
The half-value width of the melting endothermic peak in the differential scanning calorimetry is 6.00 ° C. or less,
The viscosity average molecular weight is 1 million or more and 10 million or less,
Polyethylene powder having an average particle size of 100 μm or more and 300 μm or less.
[2]
The polyethylene powder according to [1], wherein the number ratio of particles having an aspect ratio of 0.66 to 0.84 with respect to all particles is 50% or more.
[3]
The polyethylene powder according to [1] or [2], wherein the number ratio of the irregularities defined by the following formula (1) is 0.95 or more with respect to all particles is 25% or more.
UD = A / (A + B) (1)
(In Formula (1), UD represents the degree of unevenness, A represents the projected area of the target particle, and (A + B) represents the projected area surrounded by the envelope connecting the convex portions of the target particle.) )
[4]
The polyethylene powder according to any one of [1] to [3], which is used for fibers.
[5]
The fiber manufactured using the polyethylene powder as described in [4].

  According to the polyethylene powder according to the present invention, it is possible to obtain a rapid solubility in a solvent and a molded product with less generation of undissolved material.

It is a schematic diagram explaining the method of calculating | requiring the unevenness | corrugation degree of this embodiment.

  Hereinafter, a mode for carrying out the present invention (hereinafter referred to as “the present embodiment”) will be described in detail. The following embodiments are examples for explaining the present invention, and are not intended to limit the present invention to the following contents. The present invention can be implemented with appropriate modifications within the scope of the gist.

[Polyethylene powder]
Polyethylene powder of the present embodiment (hereinafter, simply referred to as "powder" or "particles".) Has a specific surface area determined by BET method, not greater than 0.20 m ² / g or more 0.80 m ² / g, Hg The pore volume determined by the press-in method is 0.95 mL / g or less, the half-value width of the melting endothermic peak in the differential scanning calorimetry is 6.00 ° C. or less, and the viscosity average molecular weight is 1 million to 10 million. The average particle size is 100 μm or more and 300 μm or less. Although it does not specifically limit as polyethylene powder, For example, the copolymer of ethylene homopolymer and ethylene and another comonomer is mentioned.

  The ethylene homopolymer means a polymer in which 99.5 mol% or more of repeating units are composed of ethylene. When the polyethylene powder is an ethylene homopolymer, the fiber can be stretched in a high orientation and a fiber excellent in tensile strength can be obtained. Moreover, since polyethylene powder is a copolymer with another comonomer, it tends to suppress side reactions during polymerization, increase the polymerization rate, and improve the creep characteristics of the resulting fiber.

  Other comonomers are not limited to the following, but examples include α-olefins and vinyl compounds. Although it does not specifically limit as an alpha olefin, For example, a C3-C20 alpha olefin is mentioned, More specifically, a propylene, 1-butene, 4-methyl- 1-pentene, 1-hexene, Examples include 1-octene, 1-nonene, 1-decene, 1-undecene, 1-dodecene, 1-tridecene, and 1-tetradecene. Among these, propylene and 1-butene are preferable from the viewpoint of heat resistance and strength of a molded body represented by a membrane and a fiber. A comonomer may be used individually by 1 type, and may use 2 or more types together.

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

  The polyethylene powder of this embodiment may contain additives for neutralizing agents, antioxidants, and light stabilizers.

  The neutralizing agent functions as a supplementary agent such as chlorine contained in the polyethylene powder, a molding processing aid, and the like. Examples of the neutralizing agent include, but are not limited to, stearates of alkaline earth metals such as calcium, magnesium, and barium. Although content of a neutralizing agent is not specifically limited, Preferably it is 5000 mass ppm or less, More preferably, it is 4000 mass ppm or less, More preferably, it is 3000 mass ppm or less. In addition, the polyethylene powder obtained by the slurry polymerization method using a metallocene catalyst can exclude a halogen component from catalyst constituents without using a neutralizing agent.

  Examples of the antioxidant include, but are not limited to, for example, dibutylhydroxytoluene, pentaeryristyl-tetrakis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate], octadecyl-3 And phenolic compounds such as-(3,5-di-t-butyl-4-hydroxyphenyl) propionate. Although content of antioxidant is not specifically limited, Preferably it is 5000 mass ppm or less, More preferably, it is 4000 mass ppm or less, More preferably, it is 3000 mass ppm or less.

  Examples of the light-resistant stabilizer include, but are not limited to, for example, 2- (5-methyl-2-hydroxyphenyl) benzotriazole, 2- (3-t-butyl-5-methyl-2-hydroxyphenyl)- Benzotriazole light stabilizers such as 5-chlorobenzotriazole; bis (2,2,6,6-tetramethyl-4-piperidine) sebacate, poly [{6- (1,1,3,3-tetramethylbutyl ) Amino-1,3,5-triazine-2,4-diyl} {(2,2,6,6-tetramethyl-4-piperidyl) imino} hexamethylene {(2,2,6,6-tetramethyl) Hindered amine compounds such as -4-piperidyl) imino}]. Although content of a light-resistant stabilizer is not specifically limited, Preferably it is 5000 mass ppm or less, More preferably, it is 4000 ppm or less, More preferably, it is 3000 ppm or less.

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

[Specific surface area]
Specific surface area determined by the BET method of the polyethylene powder is not more than 0.20 m ² / g or more 0.80 m ² / g, preferably not more than 0.25 m ² / g or more 0.60 m ² / g, more preferably It is 0.30 m ² / g or more and 0.40 m ² / g or less. The specific surface area of the polyethylene powder of the present embodiment is a specific surface area determined by the BET method (specific surface area method), and can be determined by the method described in Examples described later.

By specific surface area is less than 0.20 m ² / g or more 0.80 m ² / g, at the same time the dissolution of the internal powder and dissolving the powder surface progresses. Thereby, it can suppress that it melt | dissolves nonuniformly and an undissolved substance generate | occur | produces.

Specific surface area is related to the surface and internal structure of the polyethylene powder. Polyethylene powder having a specific surface area of 0.20 m ² / g or more has low surface smoothness, and has many pores penetrating from the surface to the inside and many voids isolated from the outside and present inside. Such polyethylene powder has a large area in contact with the solvent when dissolved in the solvent. For this reason, the time until the solubility is lowered to become a uniform solution is short, and the production efficiency becomes better.

On the other hand, when the specific surface area is 0.80 m ² / g or less, the pores isolated from the outside and present in the interior do not increase more than the pores penetrating from the surface to the inside, and the solvent penetrates into the polyethylene powder. It becomes easy to do. Moreover, since it suppresses also that the space | gap which exists inside prevents heat conduction, solubility does not fall. For this reason, the vicinity of the particle surface is dissolved and swollen, and generation of undissolved particles inside the particles is suppressed. As a result, the particles are fused to each other on the outer surface, making it difficult to form huge aggregated particles, and suppressing the formation of defects due to the generation of hardly soluble undissolved materials.

Examples of the method for controlling the specific surface area within the above range include controlling the synthesis conditions of the catalyst used when polymerizing polyethylene and controlling the post-treatment method of the polymer slurry after polymerization. . In order to set the specific surface area to 0.20 m ² / g or more, for example, in the post-treatment of the polyethylene slurry after polymerization, the drying temperature may be 150 ° C. or less. Moreover, in order to set the specific surface area to 0.80 m ² / g or less, for example, it may be prepared so as to obtain a solid catalyst in which active sites are uniformly arranged under catalyst synthesis conditions. In the post-treatment of the polyethylene slurry, the drying temperature may be 60 ° C. or higher.

  Examples of the catalyst synthesis conditions include the concentration of the catalyst raw material in the catalyst synthesis, the addition speed of the raw material, and the stirring speed during the synthesis. Specifically, a solid catalyst in which active sites are uniformly arranged can be synthesized by diluting the concentration of the catalyst raw material, slowing the addition rate of the catalyst raw material, and increasing the stirring speed during synthesis.

  The degree of polymer chain growth using a solid catalyst depends on the distribution of active sites on the surface of the solid catalyst. A solid catalyst obtained by synthesizing a raw material having a low concentration and a slow addition of the raw material has sufficient dispersion of active sites on the surface, and the active sites do not aggregate and tend to exist uniformly. On the surface of such a solid catalyst, the growth of polymer chains is uniform. As a result, unevenness is less likely to occur on the surface of the powder. By using a solid catalyst in which active sites are uniformly arranged, there is a tendency that a polyethylene powder having an appropriate specific surface area can be obtained.

  The catalyst to be used is not particularly limited, and a general Ziegler-Natta catalyst or a metallocene catalyst can be used, but a predetermined catalyst described later is preferably used.

  Control of the post-treatment method of the polyethylene slurry after polymerization is performed by changing the drying temperature. When the drying temperature is increased, the surface of the polyethylene powder melts during drying, and pores existing on the surface tend to be blocked or unevenness is made uniform. Thus, the surface area can be reduced.

[Pore volume]
The pore volume calculated | required by the mercury intrusion method of the polyethylene powder of this embodiment is 0.95 mL / g or less, Preferably it is 0.90 mL / g or less, More preferably, it is 0.85 mL / g or less. The pore volume of the polyethylene powder of the present embodiment is a pore volume determined by a mercury intrusion method, and can be determined by the method described in Examples described later.

  When the pore volume is 0.95 mL / g or less, the solubility of the polyethylene powder is improved. The pore volume is related to the internal structure and aggregation state of the polyethylene powder. Specifically, it means the volume of pores penetrating from the surface to the inside or the space volume present in the aggregated particles when the polyethylene powder particles aggregate. Since the pore volume is 0.95 mL / g or less, the number of pores communicating from the surface does not increase so much that the solvent can reach the inside of the particle at the time of dissolution. Suppress. For this reason, the solubility of polyethylene powder becomes favorable.

  Examples of a method for controlling the pore volume within the above range include controlling the synthesis conditions of the catalyst used when polymerizing polyethylene and controlling the polymerization conditions of polyethylene. In order to set the pore volume to 0.95 mL / g or less, for example, under the polymerization conditions of polyethylene, the polymerization pressure may be 0.1 MPa or more, or the solvent content before drying the polymer is 60. It may be less than or equal to the mass%, or the catalyst and ethylene should be placed at a predetermined distance or more away so that the catalyst and ethylene are sufficiently diffused in the polymerization apparatus to come into contact and polymerize. .

  Examples of the catalyst synthesis conditions include the concentration of the catalyst raw material in the catalyst synthesis reaction and the addition rate of the raw material. Specifically, aggregation of active sites in the solid catalyst is suppressed by diluting the concentration of the catalyst raw material and slowing down the addition rate of the catalyst raw material. If the active sites are not agglomerated, the polymer that grows from the active sites that are uniformly present will not grow significantly until it comes into contact with the polymer that grows from another remote active site. For this reason, it is suppressed that an internal cavity becomes large before growth polymer contacts, and pore volume does not become large.

  The catalyst to be used is not particularly limited, and a general Ziegler-Natta catalyst and a metallocene catalyst can be used, but it is preferable to use a predetermined catalyst described later.

  The ethylene polymerization conditions include, for example, lowering the polymerization temperature, separating the catalyst introduction line outlet and the ethylene introduction line outlet as far as possible, and lowering the catalyst slurry concentration. . This tends to suppress the volume expansion of the polyethylene powder due to rapid polymerization and to obtain a polyethylene powder having a dense structure with few pores.

[Half width of melting endothermic peak]
The full width at half maximum of the melting endothermic peak in the differential scanning calorimetry of the polyethylene powder of the present embodiment is 6.00 ° C. or less, preferably 5.50 ° C. or less, more preferably 5.25 ° C. or less. The half-value width of the melting endothermic peak of the polyethylene powder of the present embodiment is the half-value width of the melting endothermic peak obtained by differential scanning calorimetry, and can be obtained by the method described in Examples described later.

  When the half width of the melting endothermic peak is 6.00 ° C. or less, the solubility of the polyethylene powder is improved. This is presumably because dissolution of the polyethylene powder in the solvent is completed in a short time due to rapid melting transition of the polymer. In addition, if the melting endothermic peak has a half-value width of 6.00 ° C. or less, it is possible to suppress the occurrence of unevenness in the melting transition of the polymer. The part that dissolves quickly and the part that is difficult to dissolve are not mixed, and the polyethylene powder is uniformly dissolved, and the production stability is improved. The heat of fusion in high molecular weight polyethylene depends on the lamellar thickness of the crystal. That is, it is considered that the fact that the half-value width of the melting endothermic peak is small correlates with the uniformity of the polyethylene crystal structure.

  As a method for controlling the half-value width of the melting endothermic peak to 6.00 ° C. or less, for example, a line outlet where a catalyst for polymerizing ethylene and a line outlet where ethylene monomer is introduced can be provided in the reactor. There is a method of installing as far as possible. Moreover, the method of suppressing the temperature nonuniformity in the reactor until it diffuses immediately after introduction by making the introduction temperature of each component the same as the inside of a reactor is mentioned. These techniques tend to suppress the rapid polymerization of polyethylene as much as possible, keep the molecular chain growth rate constant, and make the crystal structure of the polyethylene powder uniform. Moreover, the method of reducing the amount of the solvent which remain | survives inside the polymer after superposing | polymerizing ethylene is also mentioned. By reducing the content of the solvent that promotes molecular chain diffusion inside the polymer, changes in the crystal structure such as crystallization of the amorphous part can be suppressed. Moreover, the method of suppressing a temperature difference in the process from superposition | polymerization of polyethylene powder to drying is also mentioned. In particular, by keeping the drying temperature low, structural changes such as melting of polyethylene powder crystals or thickening of lamellae due to recrystallization tend to be suppressed, and the crystal structure tends to be kept uniform.

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

  When the viscosity average molecular weight (Mv) is 1 million or more, a molded product having excellent mechanical strength such as tensile strength can be obtained.

  On the other hand, when the viscosity average molecular weight (Mv) is 10 million or less, the solubility of the polyethylene powder is improved, and a uniform solution containing no undissolved material can be generated in a short time. This improves the fiber production stability and mechanical strength. In addition, stretchability is also improved.

  As a method for controlling the viscosity average molecular weight (Mv) within the above range, for example, changing the temperature at the time of polymerizing ethylene can be mentioned. The higher the polymerization temperature, the lower the molecular weight. The lower the polymerization temperature, the higher the molecular weight. Further, as another method for setting the viscosity average molecular weight (Mv) to 10 million or less, a chain transfer agent such as hydrogen may be added when polymerizing ethylene. By adding a chain transfer agent, the molecular weight of the resulting polyethylene tends to be low even at the same polymerization temperature. It is preferable to control the viscosity average molecular weight (Mv) of polyethylene by combining both the above methods.

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

  When the average particle diameter is 100 μm or more, the bulk density and fluidity of the polyethylene powder are sufficiently high, and handling properties such as charging into the hopper and measurement from the hopper tend to be better.

  Moreover, the solubility of polyethylene powder improves because an average particle diameter is 300 micrometers or less.

  In the present embodiment, the average particle size can be controlled by, for example, the particle size of the catalyst used. The larger the particle size of the catalyst, the larger the average particle size, and the smaller the catalyst particle size, the average particle size. There is a tendency to obtain a small polyethylene powder. It can also be controlled by the activity of the catalyst and the polymerization conditions of the polyethylene. More specifically, in order to set the average particle diameter to 300 μm or less, for example, under the polymerization conditions of polyethylene, the polymerization pressure may be 0.1 MPa or more, or the content of the solvent before drying the polymer is What is necessary is just to be 60 mass% or less.

[aspect ratio]
In the polyethylene powder of this embodiment, the number ratio of particles having an aspect ratio of 0.66 or more and 0.84 or less (hereinafter also referred to as “specific particles X”) to all particles is 50% or more. Preferably, it is 55% or more, more preferably 60% or more. The aspect ratio of the present embodiment can be measured by the method described in the examples described later, and the number ratio of the specific particles X can be obtained at that time.

  The specific particles X are difficult to agglomerate and tend to be undissolved. When the aspect ratio of the particles is 0.66 or more, that is, the shape of the particles does not become too flat, the particles are prevented from coming into contact with each other and the particles tend not to be fused. . Moreover, when the aspect ratio of the particles is 0.84 or less, that is, when the particles are not too close to a spherical shape, the particles are prevented from being closely packed, and the particles tend not to be fused.

  As a method for controlling the number ratio of the specific particles X within the above range, for example, controlling the synthesis conditions during the solid precipitation reaction in the synthesis conditions of the catalyst, particularly in the synthesis of the catalyst. The carrier shape can be controlled to be flat by increasing the stirring speed during the solid precipitation reaction.

[Roughness]
The polyethylene powder of the present embodiment preferably has a number ratio of particles having an unevenness degree of 0.95 or more (hereinafter also referred to as “specific particles Y”) to 25% or more with respect to all particles. More preferably, it is 30% or more. The unevenness degree of this embodiment is a value defined by the following formula (1), and can be measured by the method described in the examples described later. Moreover, content of the specific particle Y can also be calculated | required at that time.
UD = A / (A + B) (1)
In Expression (1), UD represents the degree of unevenness, A represents the projected area of the target particle, and (A + B) represents the projected area surrounded by the envelope connecting the convex portions of the target particle. The degree of unevenness is 0.00 or more and 1.00 or less, and the closer to 1.00, the more uneven the particles are, and the smoother the surface. FIG. 1 is a schematic diagram illustrating a method for obtaining the degree of unevenness according to the present embodiment. For example, the projected area (A) of the target particle is obtained from the “particle projected area” in the left diagram in FIG. Next, the projection area (A + B) surrounded by the envelope connecting the convex portions of the particle projection area is obtained as the area including the A portion and the B portion of the “convex hull” which is the right diagram in FIG. .

  When the number ratio of the specific particles Y is 25% or more, the flowability of the polyethylene powder becomes sufficiently higher, so that the handling properties such as charging into the hopper and the weighing from the hopper tend to be better. .

  As a method for controlling the number ratio of the specific particles Y within the above range, for example, the amount of heat generated by a rapid polymerization reaction that occurs when producing polyethylene powder is suppressed. As a specific method for suppressing the calorific value, for example, continuous polymerization in which ethylene gas, a solvent, a catalyst and the like are continuously supplied into the polymerization system and continuously discharged together with the generated ethylene polymer is used. Polymerization may be mentioned. In addition, the catalyst inlet line outlet should be located as far as possible from the ethylene monomer inlet line outlet, the catalyst feed concentration should be reduced, and the ethylene monomer inlet should be installed in the reactor gas phase. Is also an effective method. Thereby, a rapid polymerization reaction can be suppressed, and the generation of irregularly shaped polyethylene powder and the formation of aggregates of polyethylene powder can be suppressed. Moreover, the method of making the polyethylene powder in process actively collide is also mentioned. For example, by increasing the residence time in the drying step, powders can collide with each other, the wear thereof can be promoted, and unevenness can be reduced.

[Production method of polyethylene powder]
Although the manufacturing method of the polyethylene powder of this embodiment is not specifically limited, It can manufacture using a general Ziegler-Natta catalyst. Moreover, it is preferable to use the predetermined Ziegler-Natta catalyst described below.

The predetermined Ziegler-Natta catalyst is an olefin polymerization catalyst which is a catalyst comprising a solid catalyst component [A] and an organometallic compound component [B]. Here, the solid catalyst component [A] is, for example, an organomagnesium compound (A-1) soluble in an inert hydrocarbon solvent represented by the following formula (2) (hereinafter simply referred to as “(A-1) And a titanium compound (A-2) represented by the following formula (3) (hereinafter also simply referred to as “(A-2)”).
(M ¹ ) _α (Mg) _β (R ² ) _a (R ³ ) _b Y ¹ _c (2)
In formula (2), M ¹ represents a metal atom belonging to Group 12, Group 13, or Group 14 of the Periodic Table, and R ² and R ³ each independently represent 2 to 20 carbon atoms. Y ¹ represents an alkoxy group, a siloxy group, an allyloxy group, an amino group, an amide group, —N═CR ⁴ R ⁵ , —SR ⁶ , or a β-keto acid residue (wherein , R ⁴ , R ⁵ and R ⁶ each independently represent a hydrocarbon group having 1 to 20 carbon atoms, and when c is 2, a plurality of Y ¹ may be different from each other. , Α, β, a, b, and c are real numbers that satisfy the following relationship. 0 ≦ α, 0 <β, 0 ≦ a, 0 ≦ b, 0 ≦ c, 0 <a + b, 0 ≦ b / (α + β) ≦ 2, nα + 2β = a + b + c (where n is the valence of M ¹ is there.). M ¹ , R ² , R ³ , and Y ¹ in the case where a plurality exist are each independent.
Ti (OR ⁷ ) _d X ¹ _(4-d) (3)
In Formula (3), d is a real number of 0 or more and 4 or less, R ⁷ represents a hydrocarbon group of 1 to 20 carbon atoms, and X ¹ represents a halogen atom. When there are a plurality of R ⁷ and X ¹ , they are independent of each other.

  The inert hydrocarbon solvent used in the reaction of (A-1) and (A-2) is not limited to the following, but examples thereof include aliphatic hydrocarbons such as butane, pentane, hexane, heptane; benzene, Aromatic hydrocarbons such as toluene and xylene; and alicyclic hydrocarbons such as cyclopentane, cyclohexane, methylcyclohexane and decalin.

  (A-1) is shown in Formula (2) as a form of a complex compound of organomagnesium that is soluble in an inert hydrocarbon solvent. However, (A-1) includes all dihydrocarbylmagnesium compounds and complexes of this compound with other metal compounds.

In formula (2), when α> 0, the metal atom M ¹ is not particularly limited as long as it is a metal atom belonging to Group 12, Group 13, or Group 14 of the periodic table. , Boron and aluminum. Among these, aluminum and zinc are preferable. The ratio of magnesium to metal atom M ¹ (β / α) is not particularly limited, but is preferably 0.1 or more and 30 or less, more preferably 0.5 or more and 10 or less.

In the formula (2), the hydrocarbon group having 2 to 20 carbon atoms represented by R ² and R ³ is not limited to the following, and examples thereof include an alkyl group, a cycloalkyl group, and an aryl group. More specifically, an ethyl group, a propyl group, a butyl group, a propyl group, a hexyl group, an octyl group, a decyl group, a cyclohexyl group, and a phenyl group can be mentioned. Among these, an alkyl group is preferable.

In Formula (2), when α = 0, R ² and R ³ preferably satisfy any one of the following three groups (1), (2), and (3).
Group (1): at least one of R ² and R ³ represents a secondary or tertiary alkyl group having 4 to 6 carbon atoms, preferably R ² and R ³ both have 4 to 6 carbon atoms It represents the following alkyl group, and at least one represents a secondary or tertiary alkyl group.
Group (2): R ² and R ³ represent alkyl groups having different carbon numbers, preferably R ² represents an alkyl group having 2 or 3 carbon atoms, and R ³ has 4 or more carbon atoms. Represents an alkyl group.
Group (3): at least one of R ² and R ^3, represent a hydrocarbon group having 6 or more carbon atoms, and preferably adds the number of carbon atoms contained in the hydrocarbon group represented by R ² and R ^3, 12 or more Represents an alkyl group.

In the group (1), the secondary or tertiary alkyl group having 4 to 6 carbon atoms is not limited to the following, and examples thereof include 1-methylpropyl group, 2-methylpropyl group, 1,1- Dimethylethyl group, 2-methylbutyl group, 2-ethylpropyl group, 2,2-dimethylpropyl group, 2-methylpentyl group, 2-ethylbutyl group, 2,2-dimethylbutyl group, 2-methyl-2-ethylpropyl Groups. Among these, a 1-methylpropyl group is preferable. In the formula (2), when α = 0, for example, when R ² is a 1-methylpropyl group, (A-1) is soluble in an inert hydrocarbon solvent, and such (A- 1) also tends to give favorable results to this embodiment.

  In the group (2), examples of the alkyl group having 2 or 3 carbon atoms include, but are not limited to, an ethyl group, a 1-methylethyl group, and a propyl group. Among these, an ethyl group is preferable. The alkyl group having 4 or more carbon atoms is not limited to the following, and examples thereof include a butyl group, a pentyl group, a hexyl group, a heptyl group, and an octyl group. Among these, a butyl group and a hexyl group are preferable.

  In the group (3), the hydrocarbon group having 6 or more carbon atoms is not limited to the following, and examples thereof include a hexyl group, a heptyl group, an octyl group, a nonyl group, a decyl group, a phenyl group, and a 2-naphthyl group. Can be mentioned. Among these, an alkyl group is preferable, and among the alkyl groups, hexyl and octyl groups are more preferable.

  In general, when the number of carbon atoms contained in an alkyl group increases, it tends to be soluble in an inert hydrocarbon solvent, and the viscosity of the solution tends to increase. Therefore, it is preferable in handling to use an alkyl group having an appropriate carbon number. (A-1) can be used by diluting with an inert hydrocarbon solvent, even if a trace amount of Lewis basic compounds such as ethers, esters and amines are contained or remain in the solution. It can be used without any problem.

In Formula (2), Y ¹ represents any ^one of an alkoxy group, a siloxy group, an allyloxy group, an amino group, an amide group, —N═CR ⁴ R ⁵ , —SR ⁶ , and a β-keto acid residue. Here, R ⁴ , R ⁵ and R ⁶ each independently represents a hydrocarbon group having 1 to 20 carbon atoms. Y ¹ is preferably an alkoxy or siloxy group.

  Examples of the alkoxy group include, but are not limited to, for example, methoxy group, ethoxy group, propoxy group, 1-methylethoxy group, butoxy group, 1-methylpropoxy group, 1,1-dimethylethoxy group, pentoxy group. Hexoxy group, 2-methylpentoxy group, 2-ethylbutoxy group, 2-ethylpentoxy group, 2-ethylhexoxy group, 2-ethyl-4-methylpentoxy group, 2-propylheptoxy group, 2-ethyl Examples include -5-methyloctoxy group, octoxy group, phenoxy group, and naphthoxy group. Among these, a butoxy group, 1-methylpropoxy group, 2-methylpentoxy group, and 2-ethylhexoxy group are preferable.

  Examples of the siloxy group include, but are not limited to, for example, hydrodimethylsiloxy group, ethylhydromethylsiloxy group, diethylhydrosiloxy group, trimethylsiloxy group, ethyldimethylsiloxy group, diethylmethylsiloxy group, and triethylsiloxy group. Can be mentioned. Among these, hydrodimethylsiloxy group, ethylhydromethylsiloxy group, diethylhydrosiloxy group, and trimethylsiloxy group are preferable.

R ⁴ , R ⁵ and R ⁶ each independently preferably represent an alkyl group or aryl group having 1 to 12 carbon atoms, and more preferably an alkyl group or aryl group having 3 to 10 carbon atoms. Examples of the alkyl group or aryl group having 1 to 12 carbon atoms include, but are not limited to, for example, methyl group, ethyl group, propyl group, 1-methylethyl group, butyl group, 1-methylpropyl group, 1 , 1-dimethylethyl group, pentyl group, hexyl group, 2-methylpentyl group, 2-ethylbutyl group, 2-ethylpentyl group, 2-ethylhexyl group, 2-ethyl-4-methylpentyl group, 2-propylheptyl group 2-ethyl-5-methyloctyl group, octyl group, nonyl group, decyl group, phenyl group and naphthyl group. Of these, butyl, 1-methylpropyl, 2-methylpentyl and 2-ethylhexyl groups are preferred.

  In the formula (2), (nα + 2β = a + b + c), which is a relational expression of α, β, a, b, c, indicates the stoichiometry between the valence of the metal atom and the substituent.

In (A-1), the range of the molar composition ratio (c / (α + β)) of Y ¹ with respect to all metal atoms is 0 or more and 2 or less, and preferably 0 or more and less than 1. When the molar composition ratio is 2 or less, the reactivity of (A-1) to (A-2) tends to be improved.

In the present embodiment, the synthesis method of (A-1) is not particularly limited. For example, the formula: R ² MgX ¹ or the formula: R ² ₂ Mg (where R ² represents in the formula (2)). An organic magnesium compound represented by the formula: M ¹ R ³ n or a formula: M ¹ R ³ _(n-1) H (wherein X ¹ represents a halogen atom ₎ , M ¹ , R ³ and n are the same as those represented by formula (2).) In an inert hydrocarbon solvent, 25 to 150 ° C. React with. Furthermore, if necessary, the compound represented by the formula: Y ¹ —H (where Y ¹ represents the same as that represented by the formula (2)) is then reacted. Alternatively, (A-1) can be synthesized by reacting an organomagnesium compound and / or an organoaluminum compound having a functional group represented by the formula: Y ¹ . Among these, when the organomagnesium compound soluble in the inert hydrocarbon solvent and the compound represented by the formula: Y ¹ —H are reacted, the order of the reaction is not particularly limited. wherein in: Y ¹ how will the addition of a compound represented by -H, wherein: Y ¹ how will the addition of organomagnesium compound in the compounds represented by -H, and a method of gradually adding simultaneously both Can be mentioned.

  (A-2) is preferably titanium tetrachloride. Moreover, (A-2) may be used individually by 1 type, and may use 2 or more types together.

Examples of the hydrocarbon group having 1 to 20 carbon atoms represented by R ⁷ include, but are not limited to, for example, methyl group, ethyl group, propyl group, butyl group, pentyl group, hexyl group, 2-ethylhexyl. Group, heptyl group, octyl group, decyl group, allyl group and other aliphatic hydrocarbon groups; cyclohexyl group, 2-methylcyclohexyl group, cyclopentyl group and other alicyclic hydrocarbon groups; phenyl group, naphthyl group and other aromatic groups A hydrocarbon group is mentioned. Among these, an aliphatic hydrocarbon group is preferable. d is a real number of 0 or more and 1 or less, preferably 0. Examples of the halogen atom represented by X ¹ include a chlorine atom, a bromine atom, and an iodine atom. Among these, chlorine is preferable.

  The reaction between (A-1) and (A-2) is preferably carried out in an inert hydrocarbon solvent, and more preferably carried out in an aliphatic hydrocarbon solvent such as hexane or heptane. The molar ratio of (A-1) to (A-2) in the above reaction is not particularly limited, but the molar ratio of Ti atoms contained in (A-2) to Mg atoms contained in (A-1) ( Ti / Mg) is preferably 0.1 or more and 10 or less, more preferably 0.3 or more and 3.0 or less.

Although reaction temperature is not specifically limited, It is preferable that it is -80 degreeC or more and 150 degrees C or less, More preferably, it is -40 degreeC or more and 100 degrees C or less. The stirring speed of the reaction is not particularly limited, but is preferably 1.0 × 10 ⁵ or more and 5.0 × 10 ⁶ or less, more preferably 2.0 × 10 ⁵ or more and 2.5 × 10 ⁶ or less. It is.

  The order of adding (A-1) and (A-2) is not particularly limited. For example, (A-2) is added after (A-1), (A-) is followed by (A-). 1) is added, and (A-1) and (A-2) are added simultaneously, preferably (A-1) and (A-2) are added simultaneously. . Moreover, about the space | interval which adds (A-1) and (A-2), any method of adding continuously and adding intermittently is possible, but with the period of 3 minutes or more and 20 minutes or less It is preferable to add intermittently, and it is more preferable to add intermittently with a period of 5 minutes to 15 minutes. Although it does not specifically limit about time to add (A-1) and (A-2), 1.0 hour or more and 10 hours or less are preferable, and 2.0 hours or more and 5 hours or less are more preferable.

  The time for aging (A-1) and (A-2) is not particularly limited, but it is preferably, for example, in the range of 1.0 hour or more and 10 hours or less, and 2.0 hours or more and 5.0 hours or less. Is more preferable. By carrying out the reaction of (A-1) and (A-2) as described above, the active sites of the catalyst obtained by the reaction are more uniformly dispersed, and further the aggregation of the active sites in the solid catalyst is suppressed. Tend to be able to. Therefore, polymer chain growth does not occur locally, and the polymer chain uniformly covers the surface of the catalyst particles, so that polyethylene powder with a small pore volume can be obtained, and internal voids are suppressed while having surface irregularities. Polyethylene powder having an appropriate specific surface area tends to be obtained.

  It is preferable to remove unreacted (A-1) and (A-2) after the reaction of (A-1) and (A-2). By removing unreacted (A-1) and (A-2), it is possible to suppress the generation of amorphous polymers such as lumps, adherence to the reactor wall surface, clogging of the extraction piping, etc. As a result, it tends to be excellent in continuous production. For the removal of unreacted (A-1) and (A-2), for example, by removing the supernatant liquid in a state where the catalyst slurry is settled and adding a fresh inert hydrocarbon solvent, unreacted Things can be reduced. Further, unreacted substances can be removed by filtration using a filter or the like. As the residual amount after removal, for example, the residual chlorine concentration derived from (A-2) is preferably 1.0 mmol / L or less.

  In the present embodiment, the solid catalyst component [A] obtained by the above reaction is used as a slurry solution using an inert hydrocarbon solvent.

Examples of the predetermined Ziegler-Natta catalyst include an olefin polymerization catalyst comprising a solid catalyst component [C] and an organometallic compound component [B]. Here, the solid catalyst component [C] is, for example, an organomagnesium compound (C-1) that is soluble in an inert hydrocarbon solvent represented by the following formula (4) (hereinafter simply referred to as “(C-1) ) And a chlorinating agent (C-2) represented by the following formula (5) (hereinafter, also simply referred to as “(C-2)”) (C) -3) (hereinafter also simply referred to as “(C-3)”), the organomagnesium compound (C-4) (((1)) soluble in the inert hydrocarbon solvent represented by the formula (2) described above. A-1) and a titanium compound (C-5) represented by the above formula (3) ((A-2)). Hereinafter, it is produced simply by supporting “(C-5)”).
(M ² ) _γ (Mg) _δ (R ⁸ ) _e (R ⁹ ) _f (OR ¹⁰ ) _g (4)
In Formula (4), M ² represents a metal atom belonging to Group 12, Group 13, or Group 14 of the Periodic Table, and R ⁸ , R ^9, and R ¹⁰ each independently represent 1 carbon atom. It represents 20 or less hydrocarbon groups, and γ, δ, e, f, and g are real numbers that satisfy the following relationship. 0 ≦ γ, 0 <δ, 0 ≦ e, 0 ≦ f, 0 ≦ g, 0 <e + f, 0 ≦ g / (γ + δ) ≦ 2, kγ + 2δ = e + f + g (where k is the valence of M ² is there.). M ² , R ⁸ , R ⁹ , and R ¹⁰ in the case where a plurality exist are each independent.
H _h SiCl _i R ¹¹ _{(4- (h + i))} (5)
In formula (5), R ¹¹ represents a hydrocarbon group having 1 to 12 carbon atoms, and h and i are real numbers that satisfy the following relationship. 0 <h, 0 <i, 0 <h + i ≦ 4. When there are a plurality of R ^{11 s} , they are independent of each other.

  As (C-4), the same organic magnesium compound as (A-1) can be used, and as (C-5), the same titanium compound as (A-2) can be used. Formulas (2) and (3) in (C-4) and (C-5) are as described above for (A-1) and (A-2).

  (C-1) is shown as a complex form of organomagnesium soluble in an inert hydrocarbon solvent, but includes all dihydrocarbylmagnesium compounds and complexes of this compound with other metal compounds Is.

In the formula (4), the hydrocarbon group having 1 to 20 carbon atoms represented by R ⁸ and R ⁹ is not limited to the following, and examples thereof include an alkyl group, a cycloalkyl group, and an aryl group. More specific examples include a methyl group, an ethyl group, a propyl group, a butyl group, a propyl group, a hexyl group, an octyl group, a decyl group, a cyclohexyl group, and a phenyl group. Among these, an alkyl group is preferable.

In the formula (4), when α> 0, the metal atom M ² is not particularly limited as long as it is a metal atom belonging to Group 12, Group 13, or Group 14 of the periodic table. An atom, a boron atom, and an aluminum atom are mentioned. Among these, an aluminum atom and a zinc atom are preferable.

The ratio of magnesium to metal atom M ² (δ / γ) is not particularly limited, but is preferably 0.1 or more and 30 or less, more preferably 0.5 or more and 10 or less.

In Formula (4), when γ = 0, R ⁸ and R ⁹ preferably satisfy any one of the following three groups (4), (5), and (6).
Group (4): at least one of R ⁸ and R ⁹ represents a secondary or tertiary alkyl group having 4 to 6 carbon atoms, preferably both R ⁸ and R ⁹ have 4 to 6 carbon atoms And at least one of them represents a secondary or tertiary alkyl group.
Group (5): R ⁸ and R ⁹ represent alkyl groups different from each other, preferably R ⁸ represents an alkyl group having 2 or 3 carbon atoms, and R ⁹ represents an alkyl group having 4 or more carbon atoms. Representing a group.
Group (6): at least one of R ⁸ and R ^9, represent a hydrocarbon group having 6 or more carbon atoms, preferably R ⁸ and the number of carbon atoms contained in the hydrocarbon group representing to the 12 or adding of R ⁹ Represents an alkyl group.

In the group (4), the secondary or tertiary alkyl group having 4 to 6 carbon atoms is not limited to the following, but examples thereof include 1-methylpropyl group, 2-methylpropyl group, 1,1 -Dimethylethyl group, 2-methylbutyl group, 2-ethylpropyl group, 2,2-dimethylpropyl group, 2-methylpentyl group, 2-ethylbutyl group, 2,2-dimethylbutyl group, 2-methyl-2-ethyl A propyl group is mentioned. Among these, a 1-methylpropyl group is preferable. In the formula (4), when γ = 0, for example, when R ⁸ is 1-methylpropyl or the like, (C-1) is soluble in an inert hydrocarbon solvent, and such (C— 1) also tends to give favorable results to this embodiment.

  In group (5), the alkyl group having 2 or 3 carbon atoms is not limited to the following, and examples thereof include an ethyl group, a 1-methylethyl group, and a propyl group. Among these, an ethyl group is preferable. The alkyl group having 4 or more carbon atoms is not limited to the following, and examples thereof include a butyl group, a pentyl group, a hexyl group, a heptyl group, and an octyl group. Among these, a butyl group and a hexyl group are preferable.

  In the group (6), the hydrocarbon group having 6 or more carbon atoms is not limited to the following, and examples thereof include a hexyl group, a heptyl group, an octyl group, a nonyl group, a decyl group, a phenyl group, and a 2-naphthyl group. Can be mentioned. Among these, an alkyl group is preferable, and among the alkyl groups, a hexyl group and an octyl group are more preferable.

  In general, when the number of carbon atoms contained in an alkyl group increases, it tends to be soluble in an inert hydrocarbon solvent, and the viscosity of the solution tends to increase. Therefore, it is preferable in handling to use an alkyl group having an appropriate carbon number. (C-1) can be used by diluting with an inert hydrocarbon solvent, even if a trace amount of Lewis basic compounds such as ethers, esters and amines are contained or remain in the solution. It can be used without any problem.

In the formula (4), the hydrocarbon group having 1 to 20 carbon atoms represented by R ¹⁰ is preferably an alkyl group or aryl group having 1 to 12 carbon atoms, preferably an alkyl group or aryl group having 3 to 10 carbon atoms. More preferred. Examples of the hydrocarbon group having 1 to 20 carbon atoms include, but are not limited to, for example, methyl group, ethyl group, propyl group, 1-methylethyl group, butyl group, 1-methylpropyl group, 1,1 -Dimethylethyl group, pentyl group, hexyl group, 2-methylpentyl group, 2-ethylbutyl group, 2-ethylpentyl group, 2-ethylhexyl group, 2-ethyl-4-methylpentyl group, 2-propylheptyl group, 2 -Ethyl-5-methyloctyl group, octyl group, nonyl group, decyl group, phenyl group, naphthyl group can be mentioned. Among these, a butyl group, 1-methylpropyl group, 2-methylpentyl group and 2-ethylhexyl group are preferable.

  The relational expression of symbols γ, δ, e, f and g in formula (4): (kγ + 2δ = e + f + g) indicates the stoichiometry between the valence of the metal atom and the substituent.

Although the synthesis method of (C-1) is not particularly limited, for example, the formula: R ⁸ MgX ¹ or the formula: R ⁸ ₂ Mg (R ⁸ represents the same as that represented by formula (4), X ¹ represents a halogen atom) and a formula: M ² R ⁹ _k or a formula: M ² R ⁹ _(k-1) H (M ² , R ⁹ and k are represented by the formula: The organic metal compound represented by (4) is reacted in an inert hydrocarbon solvent at a temperature of 25 ° C. or higher and 150 ° C. or lower. Further, if necessary, the alcohol or inert hydrocarbon solvent having a hydrocarbon group represented by R ⁹ (R ⁹ is the same as that represented by formula (4)) is subsequently added. A method of reacting with an alkoxymagnesium compound and / or alkoxyaluminum compound having a soluble hydrocarbon group represented by R ⁹ is preferred. Among these, the order of reacting the organomagnesium compound soluble in the inert hydrocarbon solvent and the alcohol is not particularly limited. However, the method of adding the alcohol to the organomagnesium compound, the organomagnesium compound in the alcohol, and the like. The method of adding and the method of adding both simultaneously are mentioned.

  The reaction ratio between the organomagnesium compound and the alcohol is not particularly limited, but the molar composition ratio (g / (γ + δ)) of alkoxy groups to all metal atoms in the resulting alkoxy group-containing organomagnesium compound as a result of the reaction is: It is 0 or more and 2.0 or less, and preferably 0 or more and less than 1.0.

  (C-2) is a chlorinating agent represented by the formula (5), and at least one is a silicon chloride compound having a Si—H bond.

In the formula (5), the hydrocarbon group having 1 to 12 carbon atoms represented by R ¹¹ is not limited to the following, and examples thereof include an aliphatic hydrocarbon group, an alicyclic hydrocarbon group, and an aromatic carbon group. A hydrogen group, and more specifically, a methyl group, an ethyl group, a propyl group, a 1-methylethyl group, a butyl group, a pentyl group, a hexyl group, an octyl group, a decyl group, a cyclohexyl group, and a phenyl group. . Among these, 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.

  H and i are real numbers larger than 0 satisfying the relationship of (h + i ≦ 4), and i is preferably a real number of 2 or more and 3 or less.

Examples of (C-2) include, but are not limited to, HSiCl ₃ , HSiCl ₂ CH ₃ , HSiCl ₂ C ₂ H ₅ , HSiCl ₂ (C ₃ H ₇ ), HSiCl ₂ (2-C ₃ H ₇ ), HSiCl ₂ (C ₄ H ₉ ), HSiCl ₂ (C ₆ H ₅ ), HSiCl ² (4-Cl—C ₆ H ₄ ), HSiCl ₂ (CH═CH ₂ ), HSiCl ₂ (CH ₂ C _{6) ^{H 5), HSiCl 2 (1}} -C 10 H 7), HSiCl 2 (CH 2 CH = CH 2), H 2 SiCl (CH 3), H 2 SiCl (C 2 H 5), HSiCl (CH 3) 2 HSiCl (C ₂ H ₅ ) ₂ , HSiCl (CH ³ ) (2-C ₃ H ₇ ), HSiCl (CH ₃ ) (C ₆ H ₅ ), and HSiCl (C ₆ H ₅ ) ₂ . Among these, HSiCl ₃ , HSiCl ₂ CH ₃ , HSiCl (CH ₃ ) ₂ , and HSiCl ₂ (C ₃ H ₇ ) are preferable, and HSiCl ₃ and HSiCl ₂ CH ₃ are more preferable. (C-2) may be used alone or in combination of two or more.

  In the reaction between (C-1) and (C-2), (C-2) is preliminarily inert hydrocarbon solvent; chlorinated hydrocarbon such as 1,2-dichloroethane, o-dichlorobenzene, dichloromethane, etc. Ether solvents such as diethyl ether and tetrahydrofuran; preferably used after diluting with a mixed solvent thereof. Among these, an inert hydrocarbon solvent is more preferable in terms of catalyst performance.

  The reaction ratio between (C-1) and (C-2) is not particularly limited, but the silicon atom contained in (C-2) with respect to 1 mol of magnesium atom contained in (C-1) is 0.01 mol or more. The amount is preferably 100 mol or less, more preferably 0.1 mol or more and 10 mol or less.

  The reaction method between (C-1) and (C-2) is not particularly limited. For example, simultaneous addition of (C-1) and (C-2) while simultaneously introducing (C-1) and (C-2) into the reactor is possible. Method, a method in which (C-1) is introduced into the reactor after (C-2) is charged into the reactor in advance, and (C-2) is reacted after (C-1) is charged in the reactor in advance. The method of introducing into a vessel is mentioned. Among these, the method of introducing (C-1) into the reactor after charging (C-2) into the reactor in advance is preferable. The carrier (C-3) obtained by the reaction is preferably separated by filtration or decantation, and then thoroughly washed with an inert hydrocarbon solvent to remove unreacted products or by-products. .

The reaction temperature between (C-1) and (C-2) is not particularly limited, but is preferably 25 ° C. or higher and 150 ° C. or lower, more preferably 30 ° C. or higher and 120 ° C. or lower, and still more preferably 40 It is 100 degreeC or more in the range of ℃ The stirring speed of the reaction is not particularly limited, but is preferably 1.0 × 10 ⁵ or more and 5.0 × 10 ⁶ or less, more preferably 2.0 × 10 ⁵ or more and 2.5 × 10 ⁶ or less. It is.

In the method of simultaneous addition in which (C-1) and (C-2) are simultaneously introduced into the reactor and reacted, the temperature of the reactor is adjusted to a predetermined temperature in advance, The reaction temperature is preferably adjusted to the predetermined temperature by adjusting the temperature to the predetermined temperature.
In a method in which (C-1) is introduced into the reactor after (C-2) is charged into the reactor in advance, the temperature of the reactor charged with (C-2) is adjusted to a predetermined temperature, It is preferable to adjust the reaction temperature to the predetermined temperature by adjusting the temperature in the reactor to the predetermined temperature while introducing -1) into the reactor. In the method of introducing (C-2) into the reactor after charging (C-1) into the reactor in advance, the temperature of the reactor charged with (C-1) is adjusted to a predetermined temperature, The reaction temperature is adjusted to a predetermined temperature by adjusting the temperature in the reactor to a predetermined temperature while introducing -2) into the reactor.

  The amount of (C-4) used is preferably 0.1 or more and 10 or less in terms of a molar ratio of magnesium atoms contained in (C-4) to titanium atoms contained in (C-5). More preferably, it is 5 or more and 5 or less.

  Although the temperature of reaction with (C-4) and (C-5) is not specifically limited, It is preferable that they are -80 degreeC or more and 150 degrees C or less, More preferably, they are -40 degreeC or more and 100 degrees C or less.

  The concentration of (C-4) at the time of use is not particularly limited, but is preferably 0.1 mol / L or more and 2 mol / L or less, more preferably 0.8 mol or less based on the titanium atom contained in (C-4). It is 5 mol / L or more and 1.5 mol / L or less. An inert hydrocarbon solvent is preferably used for the dilution of (C-4).

  The order of addition of (C-4) and (C-5) to (C-3) is not particularly limited, but (C-5) is added following (C-4). Subsequently, any method of adding (C-4) and simultaneously adding (C-4) and (C-5) is possible. Among these, the method of adding (C-4) and (C-5) simultaneously is preferable. Although the reaction of (C-4) and (C-5) is carried out in an inert hydrocarbon solvent, it is preferable to use an aliphatic hydrocarbon solvent such as hexane or heptane as the inert hydrocarbon solvent.

  The method of adding (C-4) and (C-5) can be performed either continuously or intermittently from the viewpoint of controlling the surface area of the polyethylene powder particles. It is preferable to intermittently add at a period of 3.0 minutes or more and 20 minutes or less, and more preferably intermittent addition at a period of 5.0 minutes or more and 15 minutes or less. Although it does not specifically limit about the time which adds (C-4) and (C-5), 1.0 hour or more and 10 hours or less are preferable, and 2.0 hours or more and 5 hours or less are more preferable. The time for aging (C-4) and (C-5) is not particularly limited, but is preferably 1.0 hour or longer and 10 hours or shorter, and more preferably 2.0 hours or longer and 5 hours or shorter. The catalyst obtained by the above reaction is used as a slurry solution using an inert hydrocarbon solvent.

  Although the usage-amount of (C-5) is not specifically limited, 0.01-20 is preferable and 0.05-10 is more preferable at the molar ratio with respect to the magnesium atom contained in a support | carrier (C-3). Moreover, the reaction temperature of (C-5) is not particularly limited, but is preferably −80 ° C. or higher and 150 ° C. or lower, and more preferably −40 ° C. or higher and 100 ° C. or lower. The method for supporting (C-5) with respect to (C-3) is not particularly limited, but a method of reacting excess (C-5) with (C-3), by using a third component The method of carrying | supporting (C-5) efficiently is mentioned, The method of carry | supporting by reaction of (C-5) and an organomagnesium compound (C-4) is preferable.

  The predetermined Ziegler-Natta catalyst of this embodiment becomes a highly active polymerization catalyst by combining the solid catalyst component [A] or the solid catalyst component [C] with the organometallic compound component [B]. The organometallic compound component [B] is sometimes called a “promoter”.

  Although it does not specifically limit as organometallic compound component [B], For example, the compound containing the metal which belongs to 1st group, 2nd group, 12th group, or 13th group of a periodic table is mentioned. Among these, an organoaluminum compound and / or an organomagnesium compound are preferable.

As the organoaluminum compound, the compound represented by Formula 5 is preferably used alone or in combination.
AlR ¹² _j Z ¹ _(3-j) (6)
In formula (6), R ¹² represents a hydrocarbon group having 1 to 20 carbon atoms, Z ¹ represents a hydrogen atom, a halogen atom, an alkoxy group, an allyloxy group, or a siloxy group, and j is 2 or more. A real number of 3 or less.

In the formula (6), the hydrocarbon group having 1 to 20 carbon atoms represented by R ¹² is not limited to the following, but examples thereof include an aliphatic hydrocarbon group, an aromatic hydrocarbon group, and an alicyclic group. A hydrocarbon group is mentioned.

  The compound represented by the formula (6) is not limited to the following, but for example, trimethylaluminum, triethylaluminum, tripropylaluminum, tributylaluminum, tri (2-methylpropyl) aluminum (also referred to as triisobutylaluminum). ), Tripentylaluminum, tri (3-methylbutyl) aluminum, trihexylaluminum, trioctylaluminum, tridecylaluminum and the like trialkylaluminum compounds; diethylaluminum chloride, ethylaluminum dichloride, bis (2-methylpropyl) aluminum chloride, Halogenated aluminum compounds such as ethylaluminum sesquichloride and diethylaluminum bromide; diethylaluminum ethoxide, bis (2 Alkoxy aluminum compounds such methylpropyl) aluminum butoxide; dimethylhydrosiloxy aluminum dimethyl, ethyl methyl hydro siloxy aluminum diethyl, siloxy aluminum compounds such as ethyl dimethylsiloxy aluminum diethyl and the like. Among these, a trialkylaluminum compound is preferable.

  As the organomagnesium compound, it is preferable to use an organomagnesium compound which is represented by the above-described formula (4) also represented by (C-1) and which is soluble in an inert hydrocarbon solvent, alone or in combination. .

The organomagnesium compound as the organometallic compound component [B] is the same compound as the organomagnesium compound represented by the formula (4) as described above as (C-1). Since it is preferable that the solubility in a hydrogen fluoride solvent is higher, (β / α) is preferably in the range of 0.5 to 10, and more preferably a compound in which M ² represents aluminum.

  The method for adding the solid catalyst component [A] or the solid catalyst component [C] and the organometallic compound component [B] into the polymerization system under the polymerization conditions is not particularly limited, but both are separately polymerized. It may be added inside, or may be added into the polymerization system after reacting both in advance. Moreover, the ratio of both to combine is although it does not specifically limit, It is preferable that organometallic compound component [B] is 1 mmol or more and 3000 mmol or less with respect to 1 g of solid catalyst component [A] or [C].

  Examples of the polymerization method include a method of (co) polymerizing ethylene or a monomer containing ethylene by a suspension polymerization method or a gas phase polymerization method. Among these, the suspension polymerization method is preferable from the viewpoint of efficiently removing the heat of polymerization. In the suspension polymerization method, an inert hydrocarbon medium can be used as a medium, or an α-olefin itself that becomes a monomer may be used as a solvent.

  Examples of the inert hydrocarbon medium include, but are not limited to, aliphatic hydrocarbons such as propane, butane, isobutane, pentane, isopentane, hexane, heptane, octane, decane, dodecane, and kerosene; cyclopentane, cyclohexane, methyl And cycloaliphatic hydrocarbons such as cyclopentane; aromatic hydrocarbons such as benzene, toluene and xylene; halogenated hydrocarbons such as ethylene chloride, chlorobenzene and dichloromethane; and mixtures thereof.

  Although superposition | polymerization temperature is not specifically limited, For example, it is preferable that it is 30 to 100 degreeC, More preferably, it is 35 to 90 degreeC, More preferably, it is 40 to 80 degreeC. When the polymerization temperature is 30 ° C. or higher, industrially efficient production tends to be possible. Further, when the polymerization temperature is 100 ° C. or lower, there is a tendency that stable operation can be continuously performed.

  The polymerization pressure is not particularly limited, but from the viewpoint of the average particle diameter of the polyethylene powder, it is preferably 0.1 MPa or more and 2.0 MPa or less, more preferably 0.1 MPa or more and 1.5 MPa or less, and further preferably It is 0.1 MPa or more and 1.0 MPa or less.

  The polymerization reaction can be carried out by any of batch, semi-continuous and continuous methods, but it is preferred to carry out polymerization in a continuous manner. By continuously polymerizing, ethylene gas, solvent, catalyst, etc. are continuously fed into the polymerization system and discharged together with the generated ethylene (co) polymer, resulting in a rapid reaction of ethylene. It is possible to suppress a typical high temperature state, and the polymerization system tends to become more stable. In addition, it is preferable that ethylene gas, a solvent, a catalyst, and the like before being supplied to the polymerization reactor are supplied at the same temperature as in the reactor in order to stabilize the system. When ethylene reacts in a uniform state in the system, it tends to be able to suppress the formation of branches, double bonds, etc. in the polymer chain. Further, the surface deformation of the polyethylene powder due to the decomposition and crosslinking of the ethylene (co) polymer tends to be suppressed. Therefore, the continuous type in which the inside of the polymerization system tends to be more uniform is preferable. Furthermore, the polymerization can be carried out in two or more stages having different reaction conditions.

  By adding hydrogen as a chain transfer agent at an appropriate concentration in the polymerization system, the molecular weight tends to be controlled within an appropriate range. By adding hydrogen into the polymerization system, in addition to controlling the molecular weight, there is a tendency that the chain transfer of the catalyst can be promoted to suppress the polymerization growth. This tends to suppress rapid polymer chain growth and prevent the formation of distorted particles. When hydrogen is added into the polymerization system, the molar fraction of hydrogen is preferably 0 mol% or more and 30 mol% or less, more preferably 3.0 mol% or more and 25 mol% or less with respect to the entire system. More preferably, it is 5.0 mol% or more and 20 mol% or less.

  Moreover, it is more preferable to add hydrogen into the polymerization system from the catalyst introduction line after contacting the catalyst in advance. Immediately after the catalyst is introduced into the polymerization system, the catalyst concentration near the inlet of the introduction line is high, and ethylene reacts rapidly, increasing the possibility of partial high-temperature conditions. Here, by bringing hydrogen and the catalyst into contact with each other before introducing them into the polymerization system, it is possible to suppress the initial activity of the catalyst, and the particle shape in the initial stage of the polymerization of polyethylene powder that has become a high temperature state due to rapid polymerization It tends to be possible to suppress the shape change.

  The deactivation method of the Ziegler-Natta catalyst used for synthesizing the polyethylene powder is not particularly limited, but it is preferable to carry out the method after separating the polyethylene powder and the solvent to some extent. By introducing an agent for deactivating the catalyst after separation from the solvent, low molecular weight components remaining in the solvent tend to be reduced and the crystal structure in the molecule can be made uniform.

  In the solvent separation step, the liquid content remaining in the polyethylene slurry is preferably 10% by mass or more and 60% by mass or less, more preferably 15% by mass or more and 55% by mass or less from the viewpoint of controlling the melting endotherm of the polyethylene powder. Preferably, 20 mass% or more and 50 mass% or less are more preferable. When the liquid content is 10% by mass or more, the increase in the particle surface tension of the polyethylene powder is suppressed, and the penetration of the deactivating agent into the particles is not difficult in the catalyst deactivation process. There is a tendency to suppress the possibility of occurrence of unevenness. When the liquid content is 60% by mass or less, the increase in the low molecular weight component remaining in the polyethylene powder is suppressed, and the site that dissolves easily in the polymer does not localize, so uniform solubility and moderate Tend to obtain a good melting behavior.

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

  The drying temperature after separating the solvent is not particularly limited, but is preferably 60 ° C. or higher and 150 ° C. or lower, more preferably 70 ° C. or higher and 140 ° C. or lower from the viewpoint of controlling the surface area of the polyethylene powder. Yes, more preferably 80 ° C. or higher and 130 ° C. or lower. When the drying temperature is 60 ° C. or higher, efficient drying tends to be possible. In addition, when the drying temperature is 150 ° C. or lower, drying tends to be possible in a state in which decomposition and crosslinking of the ethylene polymer are suppressed, and the particles are not exposed to the surrounding environment above the melting point of the polyethylene powder. It tends to suppress partial melting. In addition, since the rearrangement of the crystal structure is difficult to occur in the polyethylene powder, particularly on the outer surface, the crystal structure in the molecule tends to be uniform. Furthermore, the particles of the polyethylene powder collide with each other while the surface is dissolved, and in order to suppress the transfer while fusing, there is a tendency to suppress the increase in the average particle size due to the formation of macromolecules. .

〔fiber〕
The polyethylene powder of this embodiment is preferably used for fibers. The fiber manufactured using the polyethylene powder of this embodiment can be suitably processed as a fiber by a general spinning method. For example, in an extruder equipped with a circular die by a wet method using a solvent, a yarn is obtained by a processing method that is extruded into a gel and is subjected to stretching, extraction, and drying, and the fibers are further stretched by a processing method. Can be obtained.

[Use]
According to the polyethylene powder of the present embodiment, it is possible to obtain quick solubility in a solvent, a molded product with less generation of undissolved material, and good fluidity and spinning stability. Therefore, the polyethylene powder of this embodiment can be suitably used as a raw material for fibers that require high strength. The fiber obtained from the polyethylene powder of the present embodiment is a high-performance textile such as various sports clothing, bulletproof / protective clothing / protective gloves, various safety products; various rope products such as tag rope / mooring rope, yacht rope, building rope; Various braid products such as fishing lines and blind cables; net products such as fishing nets and ball-proof nets; reinforcing materials such as chemical filters and battery separators; curtain materials such as various nonwoven fabrics and tents; sports for helmets and skis, speaker cones It can be applied to a wide range of industries such as reinforced fibers for composites such as prepreg and concrete reinforcement.

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

(Physical property 1) Specific surface area Using polyethylene powder as a sample, the specific surface area was determined by the BET method. The specific surface area was measured using “Autosorb 3MP” (trade name) manufactured by Yuasa Ionics Co., Ltd. As pretreatment, 1 g of polyethylene powder was placed in a sample cell, and heated and deaerated with a sample pretreatment apparatus at 80 ° C. and 0.01 mmHg or less for 12 hours. Then, it measured by BET method on the conditions of measurement temperature-196 degreeC using nitrogen as adsorption gas.

(Physical property 2) Pore volume Using polyethylene powder as a sample, the pore volume was determined by mercury porosimetry. The pore volume and pore distribution were measured using Shimadzu Corporation “Autopore IV9500 type” (trade name) as a mercury porosimeter. As a pretreatment, 0.5 g of polyethylene powder was placed in a sample cell, and after deaeration and drying at room temperature in a low-pressure measuring section, mercury was filled in the sample container. Mercury was pressed into the sample pores by gradually applying pressure. The pressure conditions were set as follows.
Low pressure part: measured at 69 Pa (0.01 psia) N ₂ pressure High pressure part: 21 to 228 MPa (3,000 to 33,000 psia)

(Physical property 3) Half end width of melting endothermic peak Using polyethylene powder as a sample, the half width of melting endothermic peak was measured using a differential scanning calorimeter (DSC) (Perkin Elmer Pyris 1 DSC). The sample was weighed 8.4 g (8.3-8.5 g) with a spectroscopic balance. The sample was then placed in an aluminum sample pan. The pan was fitted with an aluminum cover and placed in a differential scanning calorimeter. While purging with nitrogen at a flow rate of 20 mL / min, the sample and reference sample were held at 50 ° C. for 1 minute, then heated from 50 ° C. to 180 ° C. at a heating rate of 10 ° C./min, held at 180 ° C. for 5 minutes, and then cooled Cooled to 50 ° C. at a rate of 10 ° C./min. The melting curve obtained at that time was drawn from 60 ° C. to 155 ° C., and the half-value width of the melting endothermic peak was derived using analysis software “Pyris software (version 7)” (trade name).

(Physical property 4) Viscosity average molecular weight (Mv)
Using polyethylene powder as a sample, the viscosity average molecular weight (Mv) of the polyethylene powder was determined by the following method according to ISO 1628-3 (2010). First, 20 mg of polyethylene powder was weighed in a melting tube, and the melting tube was purged with nitrogen, and then 20 mL of decahydronaphthalene (added with 1 g / L of 2,6-di-t-butyl-4-methylphenol) was added. The polyethylene powder was dissolved by stirring at 150 ° C. for 2 hours. The drop time (t _s ) between marked lines was measured using a Canon-Fenske viscometer (manufactured by Shibata Kagaku Kikai Kogyo Co., Ltd .: Product No. -100) in a thermostatic bath at 135 ° C. Similarly, also about the sample which changed the amount of polyethylene powder into 10 mg, 5 mg, and 2 mg, the fall time (t _s ) between marked lines was measured similarly to the above. Also, do not put a polyethylene powder as a blank was measured drop time of only decahydronaphthalene a (t _b). The reduced viscosity (η _sp / C) of polyethylene powder determined according to the following formula is plotted, and the linear expression of concentration (C) (unit: g / dL) and reduced viscosity (η _sp / C) of polyethylene powder. And the intrinsic viscosity ([η]) extrapolated to a concentration of 0 was determined.
η _sp / C = (t _s / t _b −1) /0.1: (unit: dL / g)
Next, the viscosity average molecular weight (Mv) was calculated using the value of the intrinsic viscosity [η] in the following formula.
Mv = (5.34 × 10 ⁴ ) × [η] ^1.49

(Physical property 5) Average particle diameter The average particle diameter of polyethylene powder is 10 types of sieves defined by JIS Z8801 (openings: 710 μm, 500 μm, 425 μm, 355 μm, 300 μm, 212 μm, 150 μm, 106 μm, 75 μm, 53 μm). In the integral curve obtained by integrating the mass of the polyethylene powder remaining on the various sieves obtained from the classification of 100 g of polyethylene powder from the side having a small mesh opening, the particle size at which the integral value is 50%. Was defined as the average particle size.

(Physical property 6) Number ratio of specific particles X (particles having an aspect ratio of 0.66 or more and 0.84 or less) and number ratio of specific particles Y (particles having an unevenness degree of 0.95 or more) Polyethylene powder sample The number ratio of the specific particles X and the specific particles Y was determined as follows. The aspect ratio and the degree of unevenness (UD) were measured using a dynamic image method particle size distribution / particle shape evaluation apparatus “QICPIC” (trade name) manufactured by Nippon Laser Corporation. The sample is dispersed by the following airflow dry disperser, images of 4500 to 40000 particles are continuously photographed and captured, and the number of specific particles X and specific particles Y using image analysis software from the captured image information The ratio was determined. If the number of particles is within the above range, the aspect ratio and the degree of unevenness (UD) do not vary depending on the number. Other measurement conditions were set as follows. The specific method for determining the aspect ratio and the degree of unevenness is as follows.
Airflow disperser: RODOSTM (Nippon Laser Co., Ltd., trade name)
Compressed air flow dispersion pressure: 1.0 bar
Analysis mode: EQPC (circle area equivalent diameter)
Analysis measurement range: M6 (minimum pixel is 5 μm)

(aspect ratio)
With the fixed parallel lines sandwiching the particles of the target particles obtained, the maximum interval was Fmax, the minimum interval was Fmin, and the aspect ratio of all particles was determined using the following formula. After determining the aspect ratio of all particles, particles having an aspect in a specific range (0.66 or more and 0.84 or less) were determined as specific particles X, and the number ratio with respect to the total number of obtained target particles was determined.
Aspect ratio = Fmin / Fmax

(Roughness)
When the projected area of the obtained target particle is A and the projected area surrounded by the envelope connecting the convex portions of the target particle is (A + B), the UD represented by the following formula (1) is expressed as the unevenness of the particle. Degree. After obtaining the degree of unevenness of all particles, particles having an unevenness degree in a specific range (0.95 or more) were designated as specific particles Y, and the number ratio with respect to the total number of obtained target particles was obtained.
UD = A / (A + B) (1)

(Evaluation 1) Dissolution rate 14 g of polyethylene powder, 0.4 g of pentaerythryl-tetrakis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate] as an antioxidant, and liquid paraffin (Matsumura Oil) A mixture of 36 g (trade name “P-350”, manufactured by Co., Ltd.) was charged into a small kneader (trade name “LABPLASTOMILL30C150” manufactured by Toyo Seiki Co., Ltd.), and kneaded at 200 ° C. with a screw rotation of 50 rpm. The kneading time was 10 minutes. These kneaded materials are sandwiched between metal plates and pressed into a sheet by heating at 190 ° C. until the thickness becomes 1 mm with a compression molding machine (trade name “SFA-37” manufactured by Shindo Metal Co., Ltd.). Quenched to form a gel sheet.

  The obtained gel-like sheet was stretched 7 × 7 times at 120 ° C. using a simultaneous biaxial stretching machine, and liquid paraffin was extracted and removed using methylene chloride, followed by drying. The undissolved polyethylene powder is counted by visual observation of foreign matters having a size of 50 μm or more present in the obtained sheet molding 250 mm × 250 mm (observed as black spots when the stretched sheet is observed with transmitted light). Based on the obtained number, the number of foreign matters was evaluated. The dissolution rate was evaluated according to the following evaluation criteria.

(Evaluation criteria)
A: The number of foreign matters is 1 or less.
○: There are 2 or more and 4 or less foreign substances.
X: There are 5 or more foreign substances.

(Evaluation 2) Undissolved matter 14 g of polyethylene powder, 0.4 g of pentaerythryl-tetrakis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate] as an antioxidant, and liquid paraffin (Matsumura) A mixture of 36 g (manufactured by Petroleum Corporation, trade name “P-350”) was charged into a small kneading machine (trade name “LABPLASTOMILL30C150”, manufactured by Toyo Seiki Co., Ltd.), and kneaded at 200 ° C. with a screw rotation of 50 rpm. The kneading time was 20 minutes. These kneaded materials are sandwiched between metal plates and formed into a sheet by hot pressing at 190 ° C. until a thickness of 1 mm is obtained with a compression molding machine (trade name “SFA-37”, manufactured by Shinto Metal Co., Ltd.). Quenched to form a gel sheet.

  The obtained gel-like sheet was stretched 7 × 7 times at 120 ° C. using a simultaneous biaxial stretching machine, and liquid paraffin was extracted and removed using methylene chloride, followed by drying. The undissolved polyethylene powder is counted by visual observation of foreign matters having a size of 50 μm or more present in the obtained sheet molding 250 mm × 250 mm (observed as black spots when the stretched sheet is observed with transmitted light). Based on the obtained number, it evaluated by the following evaluation criteria.

(Evaluation criteria)
A: The number of foreign matters is 1 or less.
○: There are 2 or more and 4 or less foreign substances.
X: There are 5 or more foreign substances.

(Evaluation 3) Flowability The flowability of polyethylene powder was evaluated by measuring the time when the total amount of polyethylene powder 50 g was dropped using a funnel of a bulk specific gravity measuring device described in JIS K-6721: 1997, and evaluated according to the following evaluation criteria. did.

(Evaluation criteria)
A: Fall time is less than 30 seconds.
○: The falling time is 30 seconds or more and less than 40 seconds.
X: Fall time is 40 seconds or more, does not fall continuously, or does not fall.

(Evaluation 4) Spinning stability Polyethylene powder added with 500 ppm by mass of n-octadecyl-3- (4-hydroxy-3,5-di-t-butylphenyl) propionate as an antioxidant (95 mass with respect to the total mass) %) Was mixed with decalin (manufactured by Hiroshima Wako Co., Ltd.) (5% by mass with respect to the total amount) to prepare a slurry liquid. The prepared slurry liquid was put into an extruder set at a temperature of 280 ° C. to form a uniform solution. At this time, the residence time was 20 minutes. Next, this solution was spun at a single hole discharge rate of 1.1 g / min using a spinneret with a pore diameter of 0.7 mm set at 180 ° C. The discharged yarn containing the solvent was put into a 10 ° C. water bath through an air gap of 3 cm and wound at a speed of 40 m / min while rapidly cooling.

  This spinning process was continuously operated for 2 hours, and when the yarn was cut halfway, the number of times was counted, and spinning was continued again. The time required for startup was excluded from the 2 hours, and the net continuous operation was possible. The total time was 2 hours. The series of 2-hour operation was performed twice, and the average value of the number of times each yarn was broken was taken. The average value of the number of times of yarn breakage was evaluated for spinning stability according to the following evaluation criteria.

(Evaluation criteria)
A: The average number of times of thread breakage is 0.
A: The average number of times of thread breakage exceeds 0 and is 1.5 times or less.
X: The yarn breakage average value exceeds 1.5 times.

[Preparation Example 1] Solid catalyst component [A-1]
1600 mL of hexane was added to an 8 L stainless steel autoclave thoroughly purged with nitrogen. 800 mL of 1 mol / L titanium tetrachloride hexane solution and 1 mol / L composition formula AlMg ₅ (C ₄ H ₉ ) ₁₁ (OSiH) with stirring at 10 ° C. and a Reynolds number of the fluid in the reactor of 1.5 × 10 ⁶ 800 mL of a hexane solution of an organomagnesium compound represented by ₂ was added in a cycle of 5 minutes, and the addition was repeatedly stopped over 4 hours. After the addition, the temperature was slowly raised and the reaction was continued at 10 ° C. for 1 hour. After completion of the reaction, 1600 mL of the supernatant was removed, and the solid catalyst component [A-1] was prepared by washing 5 times with 1600 mL of hexane. The amount of titanium contained in 1 g of this solid catalyst component [A-1] was 3.05 mmol.

[Preparation Example 2] Solid catalyst component [A-2]
1600 mL of hexane was added to an 8 L stainless steel autoclave thoroughly purged with nitrogen. While stirring at 10 ° C. with a Reynolds number of the fluid in the reactor of 1.48 × 10 ⁶ , 800 mL of 1 mol / L titanium tetrachloride hexane solution and 1 mol / L composition formula AlMg ₅ (C ₄ H ₉ ) ₁₁ (OSiH) 800 mL of a hexane solution of an organomagnesium compound represented by ₂ was continuously added continuously over 0.5 hours. After the addition, the temperature was slowly raised and the reaction was continued at 10 ° C. for 1 hour. After completion of the reaction, 1600 mL of the supernatant was removed, and the solid catalyst component [A-2] was prepared by washing 5 times with 1600 mL of hexane. The amount of titanium contained in 1 g of this solid catalyst component [A-2] was 3.10 mmol.

[Preparation Example 3] Carrier (B-1)
A 1000 ml hexane solution of 2 mol / L hydroxytrichlorosilane was charged into an 8 L stainless steel autoclave thoroughly purged with nitrogen, and the composition formula AlMg ₅ was stirred at 65 ° C. with a Reynolds number of 1.55 × 10 ⁶ of the fluid in the reactor. 2550 mL (equivalent to 2.68 mol of magnesium) of a hexane solution of an organomagnesium compound represented by (C ₄ H ₉ ) ₁₁ (OC ₄ H ₉ ) ₂ is added dropwise over 4 hours, and the reaction is continued with stirring at 65 ° C. for 1 hour. Was continued. After completion of the reaction, the supernatant was removed and washed 4 times with 1800 mL of hexane. This solid (carrier (B-1)) was subjected to pressure decomposition using a microwave decomposing apparatus (model ETHOS TC, manufactured by Milestone General Co., Ltd.), and ICP-AES (inductively coupled plasma mass) was obtained by an internal standard method. As a result of analysis using an analyzer, model X series X7, manufactured by Thermo Fisher Scientific Co., the amount of magnesium contained per 1 g of solid was 8.31 mmol.

[Preparation Example 4] Solid catalyst component [B]
110 mL of 1 mol / L titanium tetrachloride hexane solution and 1 mol / L compositional formula AlMg ₅ (C ₄ H ₉ ) ₁₁ (OSiH) with stirring at 10 ° C. in hexane slurry containing 110 g of the above (B-1) carrier 110 mL of a hexane solution of the organomagnesium compound represented by ₂ was added in a cycle of 5 minutes, and the addition was stopped repeatedly, and simultaneously added over 2 hours. After the addition, the reaction was continued at 10 ° C. for 1 hour. After completion of the reaction, 1100 mL of the supernatant was removed, and the solid catalyst component [B] was prepared by washing twice with 1100 mL of hexane. The amount of titanium contained in 1 g of this solid catalyst component [B] was 0.75 mmol.

[Example 1]
Hexane, ethylene, and catalyst were continuously supplied to a vessel type 300 L polymerization reactor equipped with a stirrer to obtain a polymerization slurry. The polymerization temperature was kept at 70 ° C. by jacket cooling. Hexane was supplied from the bottom of the polymerization vessel at 80 L / Hr. As the catalyst, a solid catalyst component [A-1] and triisobutylaluminum as a promoter were used. The solid catalyst component [A-1] is added at a rate of 0.2 g / Hr from the middle between the liquid surface and the bottom of the polymerization vessel, and triisobutylaluminum is added at a rate of 10 mmol / Hr. -1] and then added from the same introduction line as the solid catalyst component [A-1]. The contact time between the solid catalyst component [A-1] and triisobutylaluminum was adjusted to 30 seconds. Ethylene was supplied from the bottom of the polymerization vessel to keep the polymerization pressure at 0.2 MPa. The production rate of polyethylene was 10 kg / Hr.

  The obtained polymerization slurry was continuously drawn into a flash drum having a pressure of 0.05 Mpa to separate unreacted ethylene so that the level of the polymerization reactor was kept constant. The polymerization slurry was continuously sent to a centrifuge so that the level of the flash drum was kept constant, and the polymer was separated from other solvents. Content of the solvent etc. with respect to the polymer at that time was 45 mass%. At that time, no continuous polymer was present, and the slurry extraction piping was not clogged, and the continuous operation was stable.

  The separated polymer was dried while blowing nitrogen at 85 ° C. for 4 hours. In this drying, the polymer after polymerization was sprayed with steam to deactivate the catalyst and the cocatalyst. The dried polymer was removed using a sieve having an opening of 425 μm, and the polymer that did not pass through the sieve was removed to obtain polyethylene powder PE1.

  About the polyethylene powder obtained in Example 1, it measured according to the method mentioned above, (Physical property 1) Specific surface area, (Physical property 2) Pore volume, (Physical property 3) Half width of melting endothermic peak, (Physical property 4) Viscosity average molecular weight, (Physical property 5) Average particle diameter, (Physical property 6) Number ratio of specific particles X and Y were determined. The results are shown in Table 1. Moreover, (Evaluation 1) Dissolution rate, (Evaluation 2) Undissolved material, (Evaluation 3) Fluidity, (Evaluation 4) Spinning stability were evaluated. The results are also shown in Table 1.

[Example 2]
A polyethylene powder PE2 was obtained in the same manner as in Example 1, except that the solid catalyst component [A-1] was used in place of the solid catalyst component [B-1] as the catalyst. Table 1 shows the physical properties and evaluation results of the polyethylene powder PE2.

[Example 3]
Polyethylene powder PE3 was obtained in the same manner as in Example 1 except that the polymerization reaction was adjusted so that the content of the solvent and the like before drying the polymer was changed from 45% by mass to 60% by mass. Table 1 shows the physical properties and evaluation results of the polyethylene powder PE3.

[Example 4]
A solid catalyst component [A-3] was newly obtained by the same operation as in Adjustment Example 1 except that the Reynolds number was changed to 2.5 × 10 ⁴ . Then, polyethylene powder PE4 was obtained by the same operation as Example 1 except having used solid catalyst component [A-1] instead of solid catalyst component [A-3] as a catalyst. Table 1 shows the physical properties and evaluation results of the polyethylene powder PE4.

[Example 5]
A polyethylene powder PE5 was obtained in the same manner as in Example 1 except that the polymerization temperature was changed from 70 ° C to 85 ° C. Table 1 shows the physical properties and evaluation results of the polyethylene powder PE5.

[Example 6]
A polyethylene powder PE6 was obtained in the same manner as in Example 4 except that the polymerization temperature was changed from 70 ° C to 85 ° C. Table 1 shows the physical properties of polyethylene powder PE6 and the results of evaluation.

[Comparative Example 1]
A polyethylene powder PE7 of Comparative Example 1 was obtained in the same manner as in Example 1 except that the drying temperature was changed from 85 ° C to 160 ° C. Table 2 shows the physical properties and evaluation results of the polyethylene powder PE7.

[Comparative Example 2]
A polyethylene powder PE8 of Comparative Example 2 was obtained in the same manner as in Example 1 except that the drying temperature was changed from 85 ° C to 55 ° C and the drying time was changed from 4 hours to 12 hours. Table 2 shows the physical properties and evaluation results of the polyethylene powder PE8.

[Comparative Example 3]
A polyethylene powder PE9 was obtained in the same manner as in Example 1 except that the supply of ethylene and the solid catalyst component [A-1] was both changed from the inlet close to the bottom of the polymerization vessel. Table 2 shows the physical properties and evaluation results of the polyethylene powder PE9.

[Comparative Example 4]
A polyethylene powder PE10 was obtained in the same manner as in Example 1 except that the solid catalyst component [A-1] was used in place of the solid catalyst component [A-2] as the catalyst. Table 2 shows the physical properties and evaluation results of the polyethylene powder PE10.

[Comparative Example 5]
Polyethylene powder PE11 was obtained in the same manner as in Example 1 except that the polymerization reaction was adjusted so that the content of the solvent and the like before drying the polymer was changed from 45% by mass to 65% by mass. Table 2 shows the physical properties and evaluation results of the polyethylene powder PE11.

[Comparative Example 6]
Polyethylene powder PE12 was obtained in the same manner as in Example 1 except that the polymerization temperature was changed from 70 ° C. to 85 ° C. and the polymerization reactor was further polymerized by adding 1 mol% of hydrogen to all the substances present in the system. It was. Table 2 shows various physical properties and evaluation results of the polyethylene powder PE12.

[Comparative Example 7]
Polyethylene powder PE13 was obtained in the same manner as in Example 1 except that the polymerization pressure was changed from 0.2 MPa to 0.05 MPa. Table 2 shows the physical properties and evaluation results of the polyethylene powder PE13.

[Comparative Example 8]
As the catalyst, the solid catalyst component [A-1] is replaced with the solid catalyst component [A-2], and ethylene and the solid catalyst component [A-2] are supplied from the inlet close to each other at the bottom of the polymerization vessel. A polyethylene powder PE14 was obtained in the same manner as in Example 1 except that the operation was changed. Table 2 shows the physical properties and evaluation results of the polyethylene powder PE14.

  From the above results, the polyethylene powder according to the present invention has a small surface area and internal vacancies, and exhibits excellent solubility in an appropriate solvent. Recognize. It can also be seen that the powder is uniformly dissolved in a short period of time due to the narrow half-value width of the melting endothermic peak.

  The polyethylene powder according to the present invention dissolves quickly in a solvent, generates less undissolved material, has excellent fluidity and spinning stability, and is excellent in strength of a product after molding. -Applicable to a wide range of applications such as high-strength fiber used in protective clothing, protective gloves, fiber-reinforced concrete products, helmets, etc.

Claims (5)

Specific surface area determined by BET method, and a 0.20 m ² / g or more 0.80 m ² / g or less,
The pore volume determined by the mercury intrusion method is 0.95 mL / g or less,
The half-value width of the melting endothermic peak in the differential scanning calorimetry is 6.00 ° C. or less,
The viscosity average molecular weight is 1 million or more and 10 million or less,
Polyethylene powder having an average particle size of 100 μm or more and 300 μm or less.   2. The polyethylene powder according to claim 1, wherein the number ratio of particles having an aspect ratio of 0.66 to 0.84 with respect to all particles is 50% or more. 3. The polyethylene powder according to claim 1, wherein the number ratio of particles having an unevenness degree defined by the following formula (1) of 0.95 or more to all particles is 25% or more.
UD = A / (A + B) (1)
(In Formula (1), UD represents the degree of unevenness, A represents the projected area of the target particle, and (A + B) represents the projected area surrounded by the envelope connecting the convex portions of the target particle.) )   The polyethylene powder as described in any one of Claims 1-3 used for a fiber.   The fiber manufactured using the polyethylene powder of Claim 4.

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