KR101926229B1 - Preparation method of metallocene catalyst for slurry process and preparation method of polyethylene copolymer for water pipe using the same - Google Patents

Abstract

The present invention relates to a process for preparing a metallocene catalyst suitable for a CSTR slurry production facility and a process for producing a polyethylene copolymer having excellent processability and long-term high-temperature pressure resistance characteristics by using the metallocene catalyst, and more particularly, Mixing a solid polymethyl aluminoxane composition particle, a metallocene, an antistatic agent, and a hydrocarbon solvent having a carbon atom of 4 to 14 carbon atoms to form a slurry; Polymerizing the polyethylene by mixing and stirring the slurry, the alkyl aluminum, the hydrocarbon solvent having carbon atoms of 4 to 14 carbon atoms and the ethylene monomer prepared in the step 1; And a step of filtering and drying the obtained polyethylene, and a polyethylene copolymer produced by the method.

Description

[0001] The present invention relates to a metallocene catalyst for slurry process, and to a method for preparing a polyethylene copolymer for a pipe for a feed pipe using the same,

The present invention relates to a method for preparing a metallocene catalyst suitable for a continuous stirred tank reactor (CSTR) slurry production facility, and a method for producing a polyethylene copolymer having excellent processability and long-term high-temperature pressure resistance using the metallocene catalyst .

Polyethylene, polyvinyl chloride, polypropylene, polybutene and the like are used as the raw material of the water pipe. Such a plastic pipe has a lower rigidity than a steel pipe or a cast iron pipe or a copper pipe, but has a high chemical resistance Has a good advantage and its market size is increasing day by day. In particular, polyethylene pipes have a higher toughness than other polyvinyl chloride and polypropylene pipes and can be thermally adhered, which is easy to construct and has a high resistance to chlorine contained in constants when applied to water pipes. .

However, the conventional plastic pipe of the water supply pipe has poor resistance to pressure and environmental stress cracking (ESCR) characteristic of the polyethylene resin, thereby improving physical properties by chemical crosslinking or water exchange. It is well known that such chemical crosslinking or improvement of physical properties by water exchange and application to water pipes are well known.

A chemical crosslinking pipe is a pipe formed by extruding a resin composition made by mixing polyethylene with organic peroxide such as dicumyl peroxide at a temperature higher than the decomposition temperature of the organic peroxide, and the organic peroxide is pyrolyzed to become an organic radical. Radicals are generated in the polyethylene due to the action of the organic radicals and the crosslinking of the polyethylene proceeds. A technique related to this is disclosed in Japanese Patent Publication No. 4535658/1986.

A water-based pipe is a pipe in which a silane compound such as vinyl ethoxysilane, an organic peroxide and a silanol condensation catalyst are blended, and the resulting composition is extruded by a pipe while being heated. The molded pipe is placed in an environment containing water Followed by exposure to silane crosslinking. Such techniques are described in Japanese Patent Publication No. 48-001711, Japanese Patent Publication No. 63-058090, Japanese Patent Application Publication No. 2-253076, Japanese Patent Application Laid-Open No. 7-258496, and the like.

Japanese Patent Application Laid-Open No. 8-073670 discloses a crosslinked polyethylene composition comprising a copolymer of ethylene and butene-1 having a specific melt index, and JP-A-9-324081 discloses a crosslinked polyethylene pipe comprising a polyolefin and a specific antioxidant, 3-1709031 discloses a crosslinked pipe using a polyolefin containing a large amount of double bonds, JP 57-170913 discloses a crosslinked pipe using polyethylene having a specific density and molecular weight, JP-A No. 9-020867, JP-A No. 7-157568 Crosslinked pipe using silane-modified graft polyethylene having a narrow molecular weight distribution, crosslinked pipe for drinking beverage using special organic peroxide in JP-A No. 7-041610, crosslinked pipe added with activated carbon, silica and alumina in JP 60-001252, Japanese Patent Laid-Open Publication No. 10-182757 discloses a water supply hot water pipe using a specific organic unsaturated silane, a specific radical generator, and Japanese Patent Laid-Open Publication No. 7-330992 JP-A-6-248089 discloses a crosslinked pipe using high-density polyethylene.

However, the polyethylene used as the raw material in the prior art is a polyethylene resin produced by a conventional polymerization catalyst technique such as a conventional Ziegler-Natta or vanadium catalyst. When such an ethylene polymer is used, various problems arise. That is, when a conventional ethylene polymer having a wide molecular weight distribution and a large amount of comonomer insertion in a low molecular weight component is used, the crosslinking proceeds on the low molecular weight side and the high molecular weight component is not sufficiently crosslinked. Therefore, the mechanical strength of the crosslinked pipe, Poor problems occur.

On the other hand, it is necessary to add a large amount of an unsaturated silane compound in order to sufficiently proceed silane crosslinking even to a high molecular weight component when forming a water pipe. The silane crosslinked pipe formed in this way causes problems such as odor and the like derived from an unsaturated silane compound and the like, and a large amount of die snow also occurs in the pipe extrusion molding, making it difficult to perform the extrusion work.

The metallocene catalyst system is composed of a combination of a main catalyst mainly composed of a transition metal compound centered on a Group 4 metal and a promoter, which is an organometallic compound mainly composed of aluminum. When this catalyst is used, a polymer having a narrow molecular weight distribution can be obtained according to a single active site property.

The molecular weight and molecular weight distribution of polyolefins are important factors in determining the physical properties of the polymer and the flow and mechanical properties affecting the processability of the polymer. Improving melt processability by controlling the molecular weight distribution is an important factor in making various polyolefin products (C. A. Sperat, W. A. Franta, H. W. Starkweather Jr., J. Am. Chem. Soc., 75, 1953, 6127). Especially in the case of polyethylene, enhanced toughness, strength, and environmental stress cracking resistance (ESCR) are very important. Accordingly, a method of improving the mechanical properties of a high molecular weight resin and the processability in a low molecular weight portion by producing a polyolefin having such a high molecular weight distribution has been proposed.

In recent years, attempts have been made to produce an ethylene polymer having a molecular weight distribution of 2 to 3 by using a catalyst prepared from a metallocene compound and aluminoxane. Japanese Patent Application Laid-Open No. 58-019309, Japanese Patent Application Laid-Open No. 60-035006, Japanese Patent Application Laid-Open No. 61-130314, Japanese Laid-Open Patent Application No. 61-221208, Japanese Laid-Open Patent Application No. 62-121709, Japanese Laid-Open Patent Application No. 62-121711, etc. Japanese Patent Laid-Open Publication No. 10-193468 discloses a crosslinked pipe obtained by using a polyethylene obtained by a metallocene catalyst. However, in the case of such an ethylene polymer, the molecular weight distribution is narrow and the fluidity is insufficient especially in the extrusion process of the pipe, There is a problem that the surface state of the extruded pipe is rough due to the occurrence of premature crosslinking in part and the mechanical strength is deteriorated thereby.

On the other hand, the crosslinked pipe has a problem in that it is not suitable as a drinking water pipe due to residual unreacted monomers during chemical crosslinking and cross-linking in water flow, and flexibility is low during construction and heat bonding is not easy.

It is an object of the present invention to provide a process for producing a polyethylene copolymer having a good processability and a long-term high temperature withstand voltage characteristic by using a metallocene catalyst.

It is still another object of the present invention to provide a polyethylene copolymer having excellent processability and long-term high temperature withstand voltage characteristics by using the production method according to the present invention.

Another object of the present invention is to provide a pipe formed article having excellent creep properties using the polyethylene copolymer according to the present invention, and a method for producing the same.

In order to achieve the above object,

Mixing a solid polymethylaluminoxane composition particle, a metallocene, an antistatic agent, and a hydrocarbon solvent having a carbon atom of 4 to 14 carbon atoms to prepare a slurry (step 1);

(Step 2) of copolymerizing polyethylene by mixing and stirring the slurry, the alkyl aluminum, the hydrocarbon solvent having carbon atoms of 4 to 14 carbon atoms, the ethylene monomer and the comonomer prepared in step 1 above; And

And filtering and drying the resultant polyethylene copolymer (step 3). The present invention also provides a method for producing a polyethylene copolymer.

In addition,

, A melt index flow of 0.01 to 1.0 g / 10 min, a density of 0.930 to 0.960 g / cm 3, a PDI (polydispersity index) of 3 to 10, and a xylene soluble value of 0.01 to 1.0 .

In addition,

A pipe formed body made of the polyethylene copolymer according to the present invention is provided.

The present invention can produce a polyethylene copolymer having excellent processability and long-term high temperature withstand voltage characteristics by using a metallocene catalyst.

Particularly, according to the present invention, as a result of evaluating the workability (m / min) at the time of pipe forming, the processability is evaluated. As a result, the pipe exhibits excellent pipe workability and the time required for applying the test stress in the hot water, As a result of evaluation, it is possible to produce a polyethylene copolymer for a pipe for a water pipe by exhibiting excellent hot-internal pressure creep.

1 is a schematic diagram of an overall process according to an embodiment of the present invention.
2 is a schematic view of a process for producing a catalyst slurry according to an embodiment of the present invention.
3 is a schematic diagram of a polymerization process according to an embodiment of the present invention.
4 is a schematic diagram of a CSTR slurry polymerization process including a low molecular weight recovery process according to an embodiment of the present invention.

Hereinafter, the present invention will be described in detail.

The present invention

Mixing a solid polymethylaluminoxane composition particle, a metallocene, an antistatic agent, and a hydrocarbon solvent having a carbon atom of 4 to 14 carbon atoms to prepare a slurry (step 1);

(Step 2) of copolymerizing polyethylene by mixing and stirring the slurry, the alkyl aluminum, the hydrocarbon solvent having carbon atoms of 4 to 14 carbon atoms, the ethylene monomer and the comonomer prepared in step 1 above; And

And filtering and drying the resultant polyethylene copolymer (step 3). The present invention also provides a method for producing a polyethylene copolymer.

Specifically, as the particles of the solid polyaluminoxane composition, solid polymaluminoxane particles obtained by mixing a solution of a polymethylaluminoxane composition containing polymethylaluminoxane and trimethylaluminum and an aromatic hydrocarbon solvent and heating at 80 to 200 DEG C, Can be used.

At this time, it is preferable that the molar fraction of the methyl group derived from the trimethylaluminum is 15 mol% or less relative to the total number of moles of the methyl group in the polymethylaluminoxane composition solution, and as the molar fraction of the methyl group derived from the trimethyl aluminum segment increases, And it is more preferable that it is contained in an amount of 12 mol% or less because the particles tend to be easily broken.

The polymethylaluminoxane composition solution may be a solution obtained by thermally decomposing an aluminum compound having Al-O-C bonds at 30 DEG C to 80 DEG C for 5 to 100 hours.

The aluminum compound having an Al-OC bond can be prepared by reacting trimethyl aluminum with an organic compound containing oxygen. The molar ratio of the aluminum atom contained in the trimethyl aluminum to the oxygen atom of the organic compound containing oxygen Is in the range of 1: 0.5 to 3.

The organic compound containing oxygen may be, for example, a carboxylic acid compound having a carboxy group or a carboxylic acid anhydride, and specifically includes formic acid, acetic acid, propionic acid, n-butyric acid, n- valeric acid, There may be mentioned acid addition salts such as acetic acid, n-stearic acid, oxalic acid, malonic acid, succinic acid, glutaric acid adipic acid benzoic acid phthalic acid citric acid tartaric acid lactic acid malic acid toluene acid toluene anhydride acetic anhydride propionic anhydride oxalic anhydride, Malonic acid anhydride, malonic acid anhydride, succinic anhydride, but is not limited thereto.

The aromatic hydrocarbon solvent may be at least one material selected from the group consisting of benzene, toluene, ethylbenzene, propylbenzene, butylbenzene, xylene, chlorobenzene, and dichlorobenzene, but is not limited thereto.

In the present invention, since the solid polymethylaluminoxane composition particles are used, metallocene is not required to be supported on the carrier, so that generation of impurities is minimized, and thus it is possible to produce a high-purity polyetherimine. In addition, It is possible to manufacture polyolefin quickly because it is simple to manufacture due to no need for a topical introduction procedure, and can reduce manufacturing cost.

The step of preparing the catalyst of step 1) may be carried out in two steps of stirring the solid polymethylaluminoxane composition particles and antistatic agent in a hydrocarbon solvent, reacting them, and then adding metallocene.

The hydrocarbon solvent may be a hydrocarbon solvent having carbon atoms of 4 to 14 carbon atoms and may be at least one compound selected from the group consisting of pentane, hexane, cyclohexane, methylcyclohexane, heptane, octane, decane and isopentane However, the present invention is not limited thereto.

When the antistatic agent is used in the catalyst preparation step as described above, it is possible to improve the aggregation phenomenon due to the localized catalyst agglomeration or the excessive chain growth, and it is more effective to increase the molecular weight and to improve the aggregation phenomenon than to use the antistatic agent in the polymerization step great.

Further, since the preparation of the catalyst is carried out in two stages while using an antistatic agent, it is possible to exhibit a more excellent effect of improving the aggregation phenomenon than in the case of using only the antistatic agent in the polymerization.

As the antistatic agent, at least one compound selected from the group consisting of glyceryl stearate, glyceryl monostearate, alkyl amine, ethoxylated alkyl amine, alkyl sulfonate and glyceryl ester may be used, It is not.

A registered trademark Armostat, Statsafe or Atmer, which is a commercially available antistatic agent, may be used, and Stat SAFE 3000 is most preferably used.

The antistatic agent is preferably contained in an amount of 10 parts by weight to 50 parts by weight based on 100 parts by weight of the solid polymethylaluminoxane composition particles. If the antistatic agent is contained in an amount of less than 10 parts by weight, it can not inhibit local catalyst aggregation or excessive chain growth, And if it is contained in an amount exceeding 50 parts by weight, the activity of the solid polymethylaluminoxane composition and the metallocene catalyst is reduced to generate a low molecular weight polymer and inhibit the insertion of olefins.

The metallocene may be added so that the molar ratio of the transition metal in the metallocene to the aluminum in the solid polymethylaluminoxane composition particles is 150: 1 to 600: 1.

If the metallocene catalyst is excessively added to the molar ratio, there is a problem that the amount of increase in activity relative to the amount of metallocene used is small and a low molecular weight polymer is generated. On the other hand, when the solid polymethyl aluminoxane composition particles are excessively added, There is a problem of reducing morphology.

The metallocene compound used in the present invention is a metallocene compound having a cyclopentadienyl group, a substituted cyclopentadienyl group, an indenyl group, a substituted indenyl group, a substituted indenyl group, or a substituted indenyl group in which a transition metal of Group 4 of the periodic table (for example, titanium, zirconium, , A fluorenyl group, and a substituted fluorenyl group. Examples of metallocene catalysts include bis (cyclopentadienyl) zirconium dichloride, bis (cyclopentadienyl) zirconium methyl chloride, bis (cyclopentadienyl) zirconium dimethyl, bis (methylcyclopentadienyl) zirconium dichloride (Ethylcyclopentadienyl) zirconium dichloride, bis (ethylcyclopentadienyl) zirconium methylchloride, bis (methylcyclopentadienyl) zirconium dichloride, bis Bis (pentamethylcyclopentadienyl) zirconium dimethyl chloride, bis (pentamethylcyclopentadienyl) zirconium dimethyl, bis (pentamethylcyclopentadienyl) zirconium dichloride, bis -Cyclopentadienyl) zirconium dichloride, bis (n-butyl-cyclopentadienyl) zirconium methylchloride Zirconium dichloride, bis (indenyl) zirconium methyl chloride, bis (indenyl) zirconium dimethyl, bis (2-methyl-indenyl) zirconium dichloride, bis ) Zirconium dichloride, bis (2-methyl-indenyl) zirconium dichloride, bis (2-phenyl- indenyl) zirconium dichloride, bis (Cyclopentadienyl) zirconium dichloride, dimethylsilylbis (cyclopentadienyl) zirconium methylchloride, dimethylsilylbis (cyclopentadienyl) zirconium dichloride, (Indenyl) zirconium dimethyl, dimethylsilylbis (indenyl) zirconium dichloride, dimethylsilyl (indenyl) zirconium methyl chloride, dimethylsilyl (indenyl) zirconium dimethyl, dimethyl Zirconium dichloride, dimethylsilylbis (2-methyl-indenyl) zirconium methylchloride, dimethylsilylbis (2-methyl-indenyl) zirconium dimethyl, dimethylsilylbis Zirconium dichloride, dimethylsilyl (indenyl cyclopentadienyl) zirconium dichloride, dimethylsilyl (indenylcyclopentadienyl) zirconium dimethyl, dimethylsilyl (fluorenylcyclopentadienyl) zirconium dichloride (Cyclopentadienyl) zirconium dichloride, ethylene bis (cyclopentadienyl) zirconium dichloride, dimethylsilyl (fluorenylcyclopentadienyl) zirconium dichloride, Zirconium methyl chloride, ethylene bis (cyclopentadienyl) zirconium dimethyl, ethylene bis (indenyl) zirconium dichloride, ethyl (2-methyl-indenyl) zirconium dichloride, ethylene bis (indenyl) zirconium methyl chloride, ethylene bis (indenyl) zirconium dimethyl, ethylene bis (Indenyl cyclopentadienyl) zirconium dichloride, ethylene (indenyl cyclopentadienyl) zirconium methyl chloride, ethylene (indenyl cyclopentadienyl) zirconium dimethyl, ethylene (Cyclopentadienyl) zirconium dichloride, ethylene (fluorenylcyclopentadienyl) zirconium dichloride, ethylene (fluorenylcyclopentadienyl) zirconium dichloride, ethylene (fluorenylcyclopentadienyl) (Cyclopentadienyl) zirconium methyl chloride, isopropyl bis (cyclopentadienyl) zirconium di (Indenyl) zirconium dichloride, isopropyl bis (indenyl) zirconium methyl chloride, isopropyl bis (indenyl) zirconium dimethyl, isopropyl bis (indenyl) zirconium dichloride, isopropyl (Indenyl cyclopentadienyl) zirconium dichloride, isopropyl (indenyl cyclopentadienyl) zirconium dichloride, isopropyl (2-methyl-indenyl) zirconium dichloride, Isopropyl (fluorenylcyclopentadienyl) zirconium dichloride, isopropyl (fluorenylcyclopentadienyl) zirconium methyl chloride and iso (cyclopentadienyl) zirconium dichloride, Ethylene bis (1-indenyl) zirconium dichloride, rac-ethylene bis (1-indenyl) zirconium dichloride, dimethyl (cyclopentadienyl) Ethylenebis (1-tetrahydro-indenyl) hafnium dichloride, rac-dimethylsilanediylbis (1-tetrahydroindenyl) zirconium dichloride, rac- Methyl-tetrahydrobenzenylidene) zirconium dichloride, rac-dimethylsilanediylbis (2-methyl-tetrahydrobenzenylenyl) hafnium dichloride, rac-diphenylsilandiylbis (2-methyl-tetrahydrobenzenylenyl) hafnium dichloride, rac-dimethylsilanediylbis (2-methyl-4,5-benzindenyl) zirconium dichloride, rac-diphenylsilandiylbis ) Zirconium dichloride, rac-dimethylsilanediylbis (2-methyl-4,5-benzindenyl) hafnium dichloride, rac-diphenylsilandiylbis (2-methyl- ) Zirconium dichloride, rac-diphenylsilandiylbis (2-methyl-4,5-benzindenyl) (2-methyl-5,6-cyclopentadienylindenyl) zirconium dichloride, rac-dimethylsilanediylbis (2-methyl-5,6-cyclopentadienyl) zirconium dichloride, Diphenylsilanediylbis (2-methyl-5,6-cyclopentadienylindenyl) zirconium dichloride, rac-diphenylsilanediylbis (2-methyl- (6-cyclopentadienylindenyl) hafnium dichloride, rac-dimethylsilylbis (2-methyl-4-phenylindenyl) zirconium dichloride, rac-dimethylsilylbis Diphenylsilylbis (2-methyl-4-phenylindenyl) zirconium dichloride, rac-diphenylsilylbis (2-methyl-4-phenylindenyl) hafnium dichloride and the like.

Step 2) comprises copolymerizing the polyethylene by mixing and stirring the slurry, the alkyl aluminum, the hydrocarbon solvent having carbon atoms of 4 to 14 carbon atoms, the ethylene monomer and the comonomer.

It is preferable that 300 to 2000 parts by weight of alkyl aluminum is contained in 100 parts by weight of the slurry. If the amount of the alkyl aluminum is less than 300 parts by weight, the bulk density of the polymer is lowered. If the amount of the alkyl aluminum is more than 2000 parts by weight, the inorganic content of the polymer may increase.

Alkylaluminum is selected from the group consisting of trimethylaluminum, triethylaluminum, tributylaluminum, triisobutylaluminum, trihexylaluminum, trioctylaluminum, diethylaluminum chloride, ethylaluminum dichloride and ethylaluminum sesquichloride The above materials may be used, but are not limited thereto.

The hydrocarbon solvent may be used for a hydrocarbon having a carbon atom of 4 to 14 carbon atoms, for example, at least one compound selected from the group consisting of pentane, hexane, cyclohexane, methylcyclohexane, heptane, octane, decane and isopentane But is not limited thereto.

The polyethylene polymerization can be carried out at 60 ° C to 90 ° C, 3 to 15 bar for 2 to 4 hours.

The prepolymerization can be carried out for a short time at a mild temperature and low pressure condition before carrying out the polymerization step, preferably at 20 ° C to 50 ° C, at 0.1 to 2 bar for 30 minutes to 2 hours.

When prepolymerization is carried out under the above conditions, a prepolymer of 0.2 to 10 g-polymer / g-catalyst can be produced. By performing the prepolymerization under the above conditions, polymerization heat control of the product polyethylene is possible, Can be mitigated.

After prepolymerization under the above conditions, polyethylene is produced through the main polymerization to produce a polyethylene having no aggregation at a high yield of 20000 g-polymer / g-catalyst.

The antistatic agent may further include an antistatic agent in the preliminary polymerization or the main polymerization step. Examples of the antistatic agent include glyceryl stearate, glyceryl monostearate, alkylamine, ethoxylated alkylamine, alkylsulfonate, But are not limited to, one or more compounds selected from the group consisting of alkyl esters,

A registered trademark Armostat, Statsafe or Atmer, which is a commercially available antistatic agent, may be used, and Stat SAFE 3000 is most preferably used.

The antistatic agent is preferably contained in an amount of 20 to 80 parts by weight based on 100 parts by weight of the slurry. If the antistatic agent is contained in an amount of less than 20 parts by weight, it may fail to inhibit localized catalyst aggregation or excessive chain growth to cause fouling or aggregation , If it exceeds 80 parts by weight, the activity of the solid polymethylaluminoxane composition and the metallocene catalyst is reduced to generate a low molecular weight polymer and inhibit the insertion of olefin.

The present polymerization may also be carried out by further including hydrogen to adjust the molecular weight of the polyethylene to be produced.

Also, as a comonomer for controlling the density in the present polymerization, propylene, 1-butene, 1-pentene, 4-methyl-1-pentene, 1-hexene, Dodecene, 1-tetradecene, 1-hexadecene, 1-icocene, norbornene, norbornene, ethylidene norbornene, vinyl norbornene, dicyclopentadiene, Butanediol, pentadiene, 1,6-hexadiene, styrene, alpha-methylstyrene, para-methylstyrene, divinylbenzene, 3-chloromethylstyrene.

The polyethylene copolymer thus obtained may be filtered and dried (Step 3) to prepare a polyethylene copolymer.

The polyethylene copolymer prepared through the step 3 had a melt index flow of 0.01 to 1.0 g / 10 min, a density of 0.930 to 0.960 g / cm3, a PDI (polydispersity index) of 3 to 10, and a xylene soluble value of 0.01 to 1.0 Lt; / RTI >

After filtration in step 3, the solvent is recovered and purified to recover the minor reactants containing the low molecular weight components, and the remaining solvent can be reused as the solvent of step 1.

The present invention can provide a method for producing a polyethylene copolymer including a low-molecular component removal process.

The low-molecular weight components produced in the polymerization process were dissolved in hexane as a polymerization solvent and low molecular weight was measured by removing hexane. The low molecular components recovered in the present invention are described as soluble yield (SY). The low molecular weight component recovered in the polymerization process is 0.2 to 1.0 wt% of the weight of the polyethylene copolymer.

The Xylene Soluble method can be used for low molecular weight measurement after polymerization. Considering that the measured value of the xylene solubility of the polyethylene copolymer for the water pipe produced in the other process is 0.2 to 1.0 wt% of the weight of the polyethylene copolymer and the measured value of xylene availability of the present invention is less than 0.1%, the low- It can be seen that the removal process is very effective.

The low-molecular component adversely affects the physical properties of the pipe forming material as a polymerization side reaction material, so that it is possible to produce a pipe formed article having excellent creep properties.

The present invention also provides a polyethylene copolymer produced by the process according to the present invention.

The polyethylene copolymer may have a melt index flow of 0.01 to 1.0 g / 10 min, a density of 0.930 to 0.960 g / cm3, a PDI (polydispersity index) of 3 to 10, and a xylene soluble value of 0.01 to 1.0.

In addition, the present invention provides a pipe formed from the polyethylene copolymer according to the present invention.

The polyethylene copolymer according to the present invention has excellent pipe workability as a result of evaluating workability on the scale of working line speed (m / min) at the time of pipe forming, and also shows that the molded pipe is subjected to test stress in hot water at high temperature The results show that the polyolefin copolymer for a pipe for a water pipe can be produced by exhibiting an excellent hot internal pressure creep.

Further, since the polyethylene copolymer according to the present invention is produced through a method of producing a polyethylene copolymer including a process of removing a low-molecular component, the low-molecular component adversely affects the physical properties of the pipe forming material as a polymerization side reaction material, ) Can be produced.

As the ethylenic copolymer obtained in the present invention, an antioxidant and a pigment for coloring may be used for the end use. As the antioxidant, a phenol-based antioxidant is mainly used for the purpose of preventing thermal oxidation when passing through an extruder and for improving long-term thermal oxidation resistance, and a usual color master batch is used as a pigment for color prescription.

The ethylene-based copolymer obtained in the present invention has excellent processability and excellent pressure resistance characteristics, so it can be applied to the use of a pipe for pipe forming. As a result, the ethylenic copolymer itself is used as a raw material as it is, so it can be easily processed in a general extruder without modification of the equipment, and the power consumption is not changed.

Hereinafter, preferred embodiments and test examples of the present invention will be described in detail.

The embodiments, test examples, and drawings described in this specification are preferred embodiments of the present invention and do not represent all the technical ideas of the present invention, so that there are various equivalents and modifications that can be substituted at the time of the present application .

< Example  1>

(1) Preparation of metallocene catalyst

To a 500 ml glass bottle in which the water had been completely removed, a magnet bar, 250 ml of hexane, 1 g of solid polymethylaluminoxane and 0.2 g of Stat SAFET 3000 were added and stirred for 30 minutes at 30 ° C so that the obtained Al / Zr ratio became 300 Ethylene bis (1-tetrahydro-indenyl) zirconium dichloride was added and the mixture was stirred at 30 占 폚 for 30 minutes.

(2) Ethylene copolymerization

A 50 L autoclave equipped with a magnetic stirrer was thoroughly purged with nitrogen, and 25 L of hexane, 25 g of triethylaluminum and 1 g of slurry catalyst were added successively.

Hydrogen / ethylene was continuously added to an autoclave at -600 mmHg and 65 deg. C, and polymerization was carried out at a temperature of 11 kg / cm2G and 70 DEG C for 2 hours. The mass flowmeter controller (MFC) and the 1-octene pump were charged at a constant rate. The feed rate of hydrogen / ethylene is 70 mmol / 50 mol and the feed amount of 1-octene is 800 ml. After completion of the polymerization, the temperature of the reactor was lowered to room temperature, unreacted gas was removed, and the polyethylene was filtered and dried to obtain a polyethylene copolymer of white powder.

(3) Pipe forming

The obtained ethylene-based copolymer was extrusion-molded by using a single-screw extruder (L / D = 22, compression ratio = 3.5) at an extrusion temperature of 210 to 230 ° C so as to have an outer diameter of 32 mm and a thickness of 2.9 mm.

< Example  2>

(1) Preparation of metallocene catalyst

The same metallocene catalyst as in Example 1 was used.

(2) Ethylene copolymerization

The polymerization was carried out in the same manner as in Example 1 except that the hydrogen / ethylene feed ratio was 65 mmol / 50 mol and the 1-octene feed amount was 900 ml to obtain a polyethylene copolymer.

(3) Pipe forming

The obtained ethylene-based copolymer was extrusion-molded by using a single-screw extruder (L / D = 22, compression ratio = 3.5) at an extrusion temperature of 210 to 230 ° C so as to have an outer diameter of 32 mm and a thickness of 2.9 mm.

< Example  3>

(1) Preparation of metallocene catalyst

The same metallocene catalyst as in Example 1 was used.

(2) Ethylene copolymerization

The polymerization was carried out in the same manner as in Example 1 except that the hydrogen / ethylene feed ratio was 48.5 mmol / 50 mol and the 1-octene feed amount was 650 ml to obtain a polyethylene copolymer.

(3) Pipe forming

The obtained ethylene-based copolymer was extrusion-molded by using a single-screw extruder (L / D = 22, compression ratio = 3.5) at an extrusion temperature of 210 to 230 ° C so as to have an outer diameter of 32 mm and a thickness of 2.9 mm.

< Example  4>

(1) Preparation of metallocene catalyst

The same metallocene catalyst as in Example 1 was used.

(2) Ethylene copolymerization

The polymerization was carried out in the same manner as in Example 1, and the hydrogenation / ethylene feeding ratio was 52 mmol / 50 mol and the 1-octene feeding amount was 700 ml to obtain a polyethylene copolymer.

(3) Pipe forming

The obtained ethylene-based copolymer was extrusion-molded by using a single-screw extruder (L / D = 22, compression ratio = 3.5) at an extrusion temperature of 210 to 230 ° C so as to have an outer diameter of 32 mm and a thickness of 2.9 mm.

< Comparative Example  1, 2>

In the comparative example, a commercially available polyethylene copolymer for a water pipe was used. Comparative Example 1 is a product produced in an isobutane slurry process in the form of a cyclic reactor, using a silica-supported metallocene catalyst as a catalyst and 1-hexene as a comonomer. In Comparative Example 2, the product used in the cyclohexane solution process was a Ziegler-Natta catalyst and a 1-octene co-monomer.

The above-mentioned ethylene-based copolymer was extrusion-molded by using a single-screw extruder (L / D = 22, compression ratio = 3.5) at an extrusion temperature of 210 to 230 ° C so as to have an outer diameter of 32 mm and a thickness of 2.9 mm.

< Experimental Example >

Pipe properties

1) 95 ° C hot internal creep

The formed pipe is tested under the conditions of Hoop stress pressure of 11 MPa, hot water of 95 ° C in the water at 20 ° C, Hoop stress pressure of 4.5 MPa, 4.3 MPa, 4.0 MPa, and Hoop stress pressure of 3.1 MPa in air at 110 ° C The time from the application of stress to the destruction was evaluated.

2) Pipe appearance

It was judged as good, normal, and bad by visual observation.

Polymerization conditions and analysis results Item Example 1 Example 2 Example 3 Example 4 H2 / C2 (mmol / mol) 70/50 65/50 48.5 / 50 52/50 Input 1-C8 (ml) 800 900 650 700 MI (2.16 kg @ 190 &lt; 0 &gt; C) 0.46 0.56 0.20 0.24 MI (21.6 kg @ 190 &lt; 0 &gt; C) 25.3 31.6 10.8 14.8 density 0.941 0.941 0.943 0.943 SY (Soluble Yield) 0.20 0.35 0.25 0.28 Xylene soluble 0.05 0.05 0.03 0.02 Catalytic activity (g / g) 22,600 21,000 25,000 24,500 Mw / Mn 5.1 5.4 5.5 5.6 Mw 164,800 155,010 141,260 136,360

Creep evaluation result Item Example (no10) Example 4
No9 Example 2
No4 Example 3
No3 Comparative Example 1 Comparative Example 2
Catalyst used Metallocene Metallocene Metallocene Metallocene Metallocene Z-N Polymerization process Hexane slurry Hexane slurry Hexane slurry Hexane slurry Isobutane slurry
(Loop) Solution polymerization Comonomer 1-C8 1-C8 1-C8 1-C8 1-C6 1-C8 MI (2.16 kg @ 190 &lt; 0 &gt; C) 0.46 0.56 0.20 0.24 0.6 0.6 MI
(21.6kg@190C) 25.3 31.6 10.8 14.8 23.2 14.5 density 0.937 0.937 0.940 0.940 0.941 0.934 Xylene soluble 0.05 0.05 0.03 0.02 0.45 1.0 Pipe processability Good Good Good Good Good Good 11.0 MPa @ 20 DEG C > 2500 806 > 2500 245 105 - 4.5 MPa @ 95 ° C 275 17 > 6200 17 One 4.3 MPa @ 95 ° C > 5100 - - > 1400 21 4.0 MPa @ 95 ° C > 5100 - > 8760 1716 > 8760 787 3.8 MPa @ 95 ° C - - - - > 8750 9100 3.1 MPa @ 110 ° C > 1100 > 1400 > 1500 13 50 2.7 MPa @ 110 ° C > 8760 64

The creep property values of the test samples were prepared by referring to ISO 9080 certification data (Exova).

The foregoing description is merely illustrative of the technical idea of the present invention, and various changes and modifications may be made by those skilled in the art without departing from the essential characteristics of the present invention. Therefore, the embodiments disclosed in the present invention are intended to illustrate rather than limit the scope of the present invention, and the scope of the technical idea of the present invention is not limited by these embodiments. The scope of protection of the present invention should be construed according to the following claims, and all technical ideas within the scope of equivalents should be construed as falling within the scope of the present invention.

Claims (15)

A step (step 1) of slurrying a solid polymethylaluminoxane composition particle, a metallocene, an antistatic agent, and a hydrocarbon solvent having carbon atoms of 4 to 14 carbon atoms,
here
The particles of the solid polymethylaluminoxane composition are obtained by mixing a polymethylaluminoxane composition solution containing polymethylaluminoxane and trimethylaluminum with an aromatic hydrocarbon solvent and heating at 80 to 200 DEG C,
The metallocene is added so that the molar ratio of the transition metal in the metallocene to the aluminum in the solid polymethylaluminoxane composition particles is 150: 1 to 600: 1,
Wherein the antistatic agent is added in an amount of 10 parts by weight to 50 parts by weight based on 100 parts by weight of the solid polymethylaluminoxane composition particles;
(Step 2) of copolymerizing polyethylene by mixing and stirring the slurry, the alkyl aluminum, the hydrocarbon solvent having carbon atoms of 4 to 14 carbon atoms, the hydrogen, the ethylene monomer and the comonomer prepared in the step 1,
as,
here
The alkyl aluminum compound is contained in an amount of 300 to 2000 parts by weight based on 100 parts by weight of the slurry,
The charging ratio of the hydrogen and the ethylene monomer is 70 to 48.5: 50 (mmol: mol)
Characterized in that the copolymerization is carried out at 60 ° C to 90 ° C, 3 to 15 bar for 2 to 4 hours; And
And filtering and drying the obtained polyethylene copolymer (Step 3).
delete delete The method according to claim 1,
Wherein the aromatic hydrocarbon solvent is at least one compound selected from the group consisting of benzene, toluene, ethylbenzene, propylbenzene, butylbenzene, xylene, chlorobenzene, and dichlorobenzene.
The method according to claim 1,
Wherein said step (1) comprises reacting said solid polymethylaluminoxane composition particles with said antistatic agent in said hydrocarbon solvent to react with said metallocene, and then adding metallocene.
6. The method of claim 5,
Wherein the antistatic agent is at least one compound selected from the group consisting of glyceryl stearate, glyceryl monostearate, alkylamine, ethoxylated alkylamine, alkylsulfonate and glyceryl ester. &Lt; / RTI &gt;
delete The method according to claim 1,
The hydrocarbon solvent having 4 to 14 carbon atoms in the carbon atoms is at least one compound selected from the group consisting of pentane, hexane, cyclohexane, methylcyclohexane, heptane, octane, decane and isopentane, Wherein the polymerization is carried out in a polymerization reactor at a pressure of 60 to 90 DEG C and 3 to 15 bar.
The method according to claim 1,
The comonomer of step 2 may be selected from the group consisting of propylene, 1-butene, 1-pentene, 4-methyl-1-pentene, 1-hexadecene, 1-hexadecene, 1-hexadecene, norbornene, norbornadiene, ethylidene norbornene, vinyl norbornene, dicyclopentadiene, 1,4-butadiene, Wherein the copolymer is at least one compound selected from the group consisting of hexadiene, styrene, alpha-methylstyrene, para-methylstyrene, divinylbenzene, and 3-chloromethylstyrene.
The method according to claim 1,
Step 2 comprises preliminarily polymerizing the slurry and the ethylene monomer at 20 DEG C to 50 DEG C in a polymerization reactor of 0.1 to 2 bar for 30 minutes to 2 hours to produce a single or copolymerized prepolymer, Lt; RTI ID = 0.0 &gt; g-polymer / g-catalyst. &Lt; / RTI &gt;
The method according to claim 1,
Wherein the solvent is recovered and purified after the filtration in the step 3 to recover the minor reactant containing the low molecular weight component and the remaining solvent is reused as the solvent of the step 1. The method for producing a polyethylene copolymer according to claim 1,
The method according to claim 1,
The polyethylene produced through step 3 had a melt index flow of 0.01 to 1.0 g / 10 min at 190 占 폚 and 2.16 kg, a density of 0.930 to 0.960 g / cm3, a PDI (polydispersity index) of 3 to 10, Wherein the polyethylene copolymer has a value of 0.01 to 1.0.
5. A process for producing a polyurethane foam, which is produced by the process of claim 1,
A melt index of 0.01 to 1.0 g / 10 min at 190 占 폚 and 2.16 kg, a density of 0.930 to 0.960 g / cm3, a PDI (polydispersity index) of 3 to 10, and a xylene soluble value of 0.01 to 1.0 As a result,
Polyethylene copolymer.
delete A pipe formed from the polyethylene copolymer according to claim 13.

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