KR101740149B1 - Ethylene copolymer having excellent processing properties - Google Patents

Abstract

More particularly, the present invention relates to a metallocene catalyst component (A), a non-halogenated monocyclopentadienyl group-4 metal compound (B), a metallocene catalyst component (C) (D) a metallocene catalyst comprising a catalyst component and a catalyst component, and (D) a carrier component.

Description

[0001] The present invention relates to an ethylene copolymer having excellent processability,

The present invention relates to an ethylene copolymer for hot water and a heating tube and more particularly to a ethylene copolymer which has the same melt index, molecular weight distribution and density as those of a conventional ethylene copolymer, while maintaining properties such as stiffness and impact resistance And an ethylene copolymer excellent in workability.

Plastic raw materials such as polyethylene, polyvinyl chloride, polypropylene, and polybutene are used as raw materials for hot water and heating pipes. Among these raw materials, polyethylene has advantages in comparing advantages and disadvantages compared to other raw materials It is dominating the market. Among the raw materials of polyethylene, there are crosslinked polyethylene and non-crosslinked polyethylene. In the crosslinked polyethylene, a crosslinking process must be added to the production process of the material, thereby causing quality problems such as additional cost and uniformity of quality. In addition, due to the nature of the crosslinked product itself, it is difficult to recycle it, which is a limiting factor for environmentally friendly factors. On the other hand, non-crosslinked polyethylene has a weak point in the internal pressure and environmental stress characteristic (ESCR) possessed by the conventional polyethylene resin itself. However, recently, the emergence of new metallocene catalysts for polyolefins has made it possible to design polyethylene resins, which have not been possible before. These weaknesses have been supplemented to become a leading source of plastic pipes for hot water and heating pipes in the market have.

The metallocenes can generally be represented by the general formula L _n MQ _p wherein M is a metal of group IIIB, IVB, VB or VIB; Q is a hydrocarbyl group having 1 to 20 carbon atoms or halogen; p is the valence of M of -2, L is the ligand bound to the metal M, and n is 4-p. This metallocene compound is activated by a combination of methyl aluminoxane (MAO) or organoaluminum and anionic Lewis acids, and is used in the production of polyethylene. A variety of methods for producing polyethylene using a catalyst using a metallocene catalyst and aluminoxane are known. However, in particular, in the case of polyethylene produced using a metallocene catalyst, the mechanical load exhibits excellent mechanical properties due to a narrow molecular weight distribution and a uniform comonomer distribution, but the motor load and resin pressure excessively increase during extrusion molding, There is a problem that the workability is poor. For example, JP-A-10-193468 discloses a crosslinked pipe using polyethylene produced with a metallocene catalyst. However, in the case of this polyethylene, there is a problem that during the extrusion processing due to a narrow molecular weight distribution, melt fracture occurs on the surface of the processed pipe, resulting in roughness, thereby deteriorating the physical properties of the pipe.

As a method for improving the extrusion processability of polyethylene, a method of widening the molecular weight distribution or introducing a long chain branch is well known. Expanding the molecular weight distribution of polyethylene may have a major effect on processability, but the method of excessively broadening the molecular weight distribution lowers the mechanical properties and transparency of the product, and the problem of blocking and surface migration due to the increase of low molecular weight And is not suitable as an improvement method of extrusion processability.

In Korean Patent No. 10-0263803, the melt index ratio (MI ₁₀ / MI ₂ ) ≥ 5.63 and the molecular weight distribution (Mw / M) ≤ (MI ₁₀ / MI ₂ ) - 4.63, Discloses a substantially linear olefin polymer having elasticity with 0.01 to 3 long branch branches and the polymer produced in such a manner has a critical shear stress at the beginning of the Gloss Melt fracture of 4 x 10 ⁶ dyne / ² < / RTI > However, the above patent does not disclose specific data on processability.

Korean Patent No. 10-0529425 describes an improved easy processing method of linear low density polyethylene having a melt index ratio (MI ₂₁ / MI ₂ ) of 35 to 80. However, the above patent does not specifically mention the long-chain branching effect, and it is difficult to consider it as the effect of long-chain branching introduction considering that the molecular weight distribution shown in the examples is 5 or more.

Korean Patent Publication No. 2010-0094931 discloses an olefin polymer having improved molecular weight distribution of 3.5 or more, improved DRI (Dow Rheology Index) of 0.3 or more, and a flow activation energy of 40 to 80 kJ / mol. Although DRI (Dow Rheology Index) shows a low value of 0.3 ~ 0.82, it is difficult to grasp the effect of improvement of processability, even though the molecular weight distribution is as wide as 3.5 ~ 8.2 and activation energy is 44 ~ 81kJ / mol. Further, the patent does not disclose specific data on processability.

Korean Patent No. 10-0646249 describes a polyethylene for a pipe for a water pipe having a melt flow index of 0.3 to 1.0 g / 10 min, a density of 0.930 to 0.945 g / mL, and a molecular weight distribution of 5 to 30 and having excellent processability. The molecular weight distribution shown in the examples is 17.3 to 18.2, and the processability at the time of pipe processing shows improved characteristics due to a broad molecular weight distribution.

European patent EP 1935 909 A1 describes a linear low density polyethylene which exhibits improved extrusion formability by introducing a long chain branch using a monocyclopentadienyl structure metallocene catalyst. 0 <DRI / MI ₂ <0.002 G'-0.745 (the elastic modulus G 'is a value at a loss modulus G "= 500 Pa) using DRI Rheology Index (DRI) However, the DRI at MI ₂ = 1 level is as low as 0.2 to 0.3, so that it is difficult to expect a large improvement in extrusion processability.

In US Pat. Nos. 5,006,255, 259 A1 and US Pat. No. 3,005,545 A1, a technique of increasing the bubble stability of polyethylene by adding a small amount of an organic peroxide has been proposed. However, the film produced in this manner is greatly degraded in mechanical properties such as impact strength and tear strength A problem arises.

The metallocene catalyst should be supported on a suitable support for use in a fluidized bed reactor or slurry reactor, and the individual catalyst particles carrying the metallocene should exhibit sufficient activity to avoid problems due to catalyst support residues.

One of the typical methods for preparing metallocene supported catalyst that is currently being developed and used is a method in which a metallocene catalyst is supported on silica together with methylaluminoxane (U.S. Patent No. 4,808,561, U.S. Patent No. 4,897,455, U.S. Patent No. 5,240,894 See also This method is a method in which a hydroxyl group of silica is reacted with methylaluminoxane to support methylaluminoxane on the surface of silica, and the metallocene catalyst is supported on the supported methylaluminoxane. The metallocene catalyst component may be carried at the same time as methylaluminoxane, or may be carried through additional reaction after methylaluminoxane is supported. The activity of the supported catalyst is proportional to the amount of metallocene component supported and also proportional to the loading of methylaluminoxane to assist in supporting the metallocene catalyst component. Methylaluminoxane not only helps to support the metallocene catalyst but also protects the metallocene catalyst component from the catalyst poison. Therefore, the loading amount of methylaluminoxane directly affects the activity of the catalyst.

Accordingly, the present inventors have proposed a non-crosslinked ethylene copolymer for a hot water and a heating pipe which is excellent in physical properties and pressure resistance characteristics and has excellent processability without excessively widening the molecular weight distribution. As a result of the study, it was found that the alpha olefin comonomer is distributed so as to be concentrated in the high molecular weight portion in the molecular weight distribution and the long chain branch is introduced into the polymer instead of appropriately controlling the molecular weight distribution, Ethylene copolymer was prepared.

Accordingly, an object of the present invention is to provide an ethylene copolymer resin which is improved in processing problems such as an increase in working load and die draw at the time of pipe working while maintaining excellent pipe physical properties such as internal pressure and environmental stress.

(2) a density of 0.930 to 0.955 g / mL; (3) a molecular weight (Mw) of at least 10 g / (4) a Broad Orthogonal Comonomer Distribution Index (BOCDI) of >0.5; (5) a critical phase angle value (? C) &Lt; 70.0. &Lt; / RTI &gt; The ethylene copolymers satisfying the above conditions (1) to (5) satisfy the physical properties and processability of the improved ethylene copolymer resin to be obtained in the present invention, and the above conditions (1) to (5) When the material was removed, satisfactory results were not obtained in terms of physical properties and workability.

Hereinafter, the contents of the present invention will be described in detail.

When there is no other definition in the technical term used in the present invention, it is understood by those having ordinary skill in the art to which the present invention belongs.

The Broad Orthogonal Comonomer Distribution Index (BOCD) used in the present invention is a concept that numerically represents the distribution of alpha olefin comonomers in the olefin copolymer. That is, GPC-IR with FTIR (Fourier Transform Infrared Spectroscopy) was analyzed and calculated for comonomer analysis in GPC. The results of GPC-IR analysis showed that the content (# / 1000C) of SCB (SCB, short chain branch, comonomer) at the upper 80% of the measured molecular weight (high molecular weight point) based on the weight average molecular weight (Mw) % (Low molecular weight point) of SCB was measured and the BIODY index was calculated by the following equation.

As can be seen from the above equation, the higher the SCB content in the high molecular weight side of the Biocyd index, the higher the value of the BiocDi index, and this structure is referred to as a BiocDi structure. Therefore, when the index of the bio-CD index is less than 0, it is not a bio-CD structure. When the index is more than 0, it may be regarded as an olefin copolymer having a bio-CD structure . The ethylene copolymer claimed in the present invention has a Biocyd value of at least 0.5, and when it is smaller, the physical properties such as pressure resistance and environmental stress characteristics are not improved.

The critical phase angle (δc) used in the present invention is a rheological method for comparing polymer materials having different structural characteristics, and in particular, the long chain brach (LCB) of the ethylene copolymer It is a useful method to confirm.

This method is also referred to as Van-Gurp Palmen analysis (Ref. 1. Rheology Bulletin, 1998, 67, 5-8, 2. Correlations between the Characteristic Rheological Quantities and Molecular Structure of Long- Chain Branched Metallocene Catalyzed Polyethylenes, Macromolecules, 2011, 44 , 5401-5413).

Linear structure polyethylene (PE) and LCB structure polyethylene were obtained through a plot of phase angle shift (δ) and complex elastic modulus (G *) obtained from a dynamic frequency sweep measured with an ARES instrument The higher the LCB at constant G * values, the lower the phase angle value. An inflection point at which the slope of the graph changes at a phase angle value (δ) and a complex elastic modulus (G *) curve is called a critical phase angle value (δ _C ) and correlates with the degree of LCB. _C is low. The ethylene copolymer claimed in the present invention has a critical phase angle value (critical phase angle value,? C) of <70.0, and when it is larger, the processing problem is not improved. Detailed analysis methods will be described below.

Hereinafter, a method for producing an ethylene copolymer of the present invention will be described. Hereinafter, an example of a manufacturing method will be described, but the present invention is not limited thereto.

The ethylene copolymer according to the present invention can be produced, for example, in a gas-phase reactor using a catalyst as described below. The ethylene copolymer thus prepared had (1) a melt flow index of 0.3 to 2.0 g / 10 min (190 DEG C, 2.16 kg load), (2) a density of 0.930 to 0.955 g / mL, (4) a Broad Orthogonal Comonomer Distribution Index (BOCD) of >0.5; (5) a critical phase angle value? C of less than or equal to 70.0. It is useful for application as a polyethylene material for heating pipes.

catalyst

The catalyst which can be used in the production of the ethylene copolymer according to the present invention is selected from the group consisting of (A) a metallocene compound, (B) a non-halogenated monocyclopentadienyl Group 4 metal compound, (C) activating cocatalysts, Component and (D) a carrier component are preferred.

Of the catalyst components, the metallocene compound (A) is not particularly limited, but is preferably a dicyclopentadienyl metallocene represented by the following general formula (1) or a bridge linkage represented by the following general formula (2) Metallocene.

First, dicyclopentadienyl metallocene can be represented by the following general formula (1).

(CpR _n ) (CpR ' _m ) ML _q (1)

Wherein Cp is cyclopentadienyl, indenyl, or fluorenyl,

R and R 'each independently represent hydrogen, alkyl, alkylether, allylether, phosphine or amine,

L represents alkyl, allyl, arylalkyl, amide, alkoxy or halogen,

M represents a transition metal of Group 4 or Group 5 of the periodic table,

n is an integer satisfying 0? n <5, m is 0? m <5, and q is 1? q? 4.

The bridged metallocene can be represented by the following general formula (2).

Q (CpR _n ) (CpR ' _m ) ML _q (2)

Q is a bridging bond between the C rings and may be a divalent linkage such as dialkyl, alkylaryl (Alkylaryl), diarylsilyl ( Diaryl silicon or a hydrocarbon group of 1 to 20 carbon atoms, n is an integer satisfying 0? N <4, m is 0? M <4, and q is 1? Q?

Examples of the dicyclopentadienyl metallocene compound satisfying the structure of the general formula (1) include, but are not limited to, bis (cyclopentadienyl) zirconium dimethyl, bis (methylcyclopentadienyl) zirconium dimethyl , Bis (n-butylcyclopentadienyl) zirconium dimethyl, bis (indenyl) zirconium dimethyl, bis (1,3-dimethylcyclopentadienyl) zirconium dimethyl, (pentamethylcyclopentadienyl) (cyclopentadienyl ) Zirconium dimethyl, bis (pentamethylcyclopentadienyl) zirconium dimethyl, bis (fluorenyl) zirconium dimethyl, bis (2-methylindenyl) zirconium dimethyl, bis (2-phenylindenyl) zirconium dimethyl, and the like. The biscyclopentadienyl metallocene may be used alone or in combination.

Examples of the bridged metallocene represented by the general formula (2) include, but are not limited to, dimethylsilylbis (1-indenyl) zirconium dimethyl, dimethylsilyl (9-fluorenyl) (1-cyclopentadienyl (1-indenyl) zirconium dimethyl, dimethylsilylbis (1-cyclopentadienyl) zirconium dimethyl, dimethylsilyl (9-fluorenyl) (1-cyclopentadienyl) hafnium dimethyl, dimethylsilylbis (1-cyclopentadienyl) hafnium dimethyl, dimethylsilyl (9-fluorenyl) (1-indenyl) hafnium dimethyl Zirconium dimethyl, ethylene bis (1-indenyl) zirconium dimethyl, ethylene bis (4,5,6,7-tetrahydro-1-indenyl) zirconium dimethyl, ethylene bis Zirconium dimethyl, ethylene bis (5-methyl-1-indenyl) zirconium dimethyl, ethylene bis (4-phenyl-1-indenyl) zirconium dimethyl, ethylene bis (5-methoxy-1-indene) zirconium dimethyl, ethylenebis (4,7-dimethyl-1-indenyl) zirconium dimethyl, ethylenebis (4,7-dimethoxy-1-indenyl) zirconium dimethyl, ethylenebis Indenyl) zirconium dimethyl, ethylene bis (trimethylcyclopentadienyl) zirconium dimethyl, ethylene bis (5-dimethylamino-1-indenyl) zirconium dimethyl, ethylene bis (1-dimethylamino-9-methylphenyl) zirconium dimethyl, ethylene bis (4,7-bis (dimethylamino) -1- indenyl) zirconium dimethyl, ethylene bis (1-cyclopentadienyl) zirconium dimethyl, ethyl (4-butylthio-9-fluorenyl) (1-cyclopentadienyl) zirconium dimethyl, ethyl (1-cyclopentadienyl) zirconium dimethyl, ethylene bis (9-fluorenyl) zirconium dimethyl, ethylene bis (1-cyclopentadienyl) hafnium dimethyl, ethylene bis ) Hafnium dimethyl, ethylenbis (4,5,6,7-tetrahydro-1-indenyl) hafnium dimethyl, ethylenebis (4-methyl-1-indenyl) hafnium dimethyl, ethylenebis Indenyl) hafnium dimethyl, ethylene bis (6-methyl-1-indenyl) hafnium dimethyl, ethylene bis (7-methyl-1-indenyl) hafnium dimethyl, Indenyl) hafnium dimethyl, ethylene bis (2,3-dimethyl-1-indenyl) hafnium dimethyl, ethylene bis (4,7-dimethyl-1-indenyl) hafnium dimethyl , Ethylene bis (4,7-dimethoxy-1-indenyl) hafnium dimethyl, ethylene bis (trimethylcyclopentadienyl) hafnium dimethyl, ethylene bis (5-dimethylamino-1-indenyl) hafnium dimethyl, ethylene Indenyl) hafnium dimethyl, ethylene bis (4,7-bis (dimethylamino) -1-indenyl) hafnium dimethyl, ethylene bis (5-diphenylphosphino- (1-cyclopentadienyl) hafnium dimethyl, ethylen (4-butylthio-9-fluorenyl) (1-cyclopentadienyl) hafnium dimethyl, ethylene (1-cyclopentadienyl) hafnium dimethyl, ethylene bis (9-fluorenyl) hafnium dimethyl, 2,2-propyl bis (1-cyclopentadienyl) zirconium dimethyl , Dimethyl 2,2-propylbis (1-indenyl) zirconium dimethyl, 2,2-propylbis (4,5,6,7-tetrahydro-1-indenyl) zirconium dimethyl, 2,2- 2-propylbis (6-methyl-1-indenyl) zirconium dimethyl, 2,2- , 2-propylbis (7-methyl-1-indenyl) zirconium dimethyl, Propylbis (5-methoxy-1-indenyl) zirconium dimethyl, 2,2-propylbis (2,3-dimethyl- 2-propylbis (4,7-dimethoxy-1-indenyl) zirconium dimethyl, 2 (2-propylphenyl) indenyl) zirconium dimethyl, (2-propylbis (trimethylcyclopentadienyl) zirconium dimethyl, 2,2-propylbis (5-dimethylamino-1-indenyl) zirconium dimethyl, Indenyl) zirconium dimethyl, 2,2-propylbis (5,7-bis (dimethylamino) -1-indenyl) zirconium dimethyl, (1-dimethylamino-9-fluorenyl) (1-cyclopentadienyl) zirconium dimethyl, 2,2-propyl (4-butylthio-9-fluorenyl) (Cyclopentadienyl) zirconium dimethyl, 2,2-propyl (9-fluorenyl) (1-cyclopentadienyl) zirconium (1-cyclopentadienyl) hafnium dimethyl, 2,2-propylbis (1-indenyl) hafnium dimethyl , Dimethyl 2,2-propylbis (4,5,6,7-tetrahydro-1-indenyl) hafnium dimethyl, 2,2-propylbis (4-methyl- (7-methyl-1-indenyl) hafnium dimethyl, 2,2-propylbis (6-methyl-1-indenyl) hafnium dimethyl, Hafnium dimethyl, 2,2-propylbis (4-phenyl-1-indenyl) hafnium dimethyl, 2,2-propyl bis (5-methoxy- (4,7-dimethyl-1-indenyl) hafnium dimethyl, 2,2-propylbis (4,7-dimethoxy- Indenyl) hafnium dimethyl, 2,2-propylbis (trimethylcyclopentadienyl) hafnium dimethyl, 2,2-propylbis (5-dimethylamino-1-indenyl) hafnium dimethyl, 2-propylbis (4,7-bis (dimethylamino) -1-indenyl) hafnium dimethyl, 2,2- 1-indenyl) hafnium dimethyl, 2,2-propyl (1-dimethylamino-9-fluorenyl) (1-cyclopentadienyl) hafnium dimethyl, 2,2- (1-cyclopentadienyl) hafnium dimethyl, 2,2-propyl (9-fluorenyl) (1-cyclopentadienyl) hafnium dimethyl, 2,2-propylbis (9-fluorenyl) hafnium dimethyl, diphenylmethylbis (1-cyclopentadienyl) zirconium dimethyl, diphenylmethylbis (1-indenyl) zirconium dimethyl, diphenylmethylbis (5-methyl-1-indenyl) zirconium dimethyl, diphenylmethylbis (4-methyl-1-indenyl) zirconium dimethyl, diphenylmethylbis (6-methyl-1-indenyl) zirconium dimethyl, diphenylmethylbis (7 (5-methoxy-1-indenyl) zirconium dimethyl, diphenylmethylbis (4-phenyl-1-indenyl) zirconium dimethyl, diphenylmethylbis (4,7-dimethyl-1-indenyl) zirconium dimethyl, diphenylmethylbis (4,7-dimethoxy-1-indenyl) zirconium dimethyl, diphenylmethylbis Diphenylmethyl-bis (trimethylcyclopentadienyl) zirconium dimethyl, diphenylmethylbis (5-dimethylamino-1-indenyl) zirconium dimethyl, diphenylmethylbis (Dimethylamino) -1-indenyl) zirconium dimethyl, diphenylmethylbis (5-diphenylphosphino-1-indenyl) zirconium dimethyl, diphenylmethylbis (1-cyclopentadienyl) zirconium dimethyl, diphenylmethyl (4-butylthio-9-fluorenyl) (1-cyclopentadienyl) zirconium (1-cyclopentadienyl) zirconium dimethyl, diphenylmethylbis (9-fluorenyl) zirconium dimethyl, diphenylmethylbis (1-cyclopentadienyl) hafnium Dimethyldiphenylmethylbis (1-indenyl) hafnium dimethyl, diphenylmethylbis (4,5,6,7-tetrahydro-1-indenyl) hafnium dimethyl, diphenylmethylbis Indenyl) hafnium dimethyl, diphenylmethylbis (5-methyl-1-indenyl) hafnium dimethyl, diphenylmethylbis (4-phenyl-1-indenyl) hafnium dimethyl, diphenylmethylbis (5-methoxy-1-indenyl) hafnium dimethyl, diphenylmethylbis (4,7-dimethoxy-1-indenyl) hafnium dimethyl, diphenylmethylbis (4,7-dimethyl-1-indenyl) hafnium dimethyl, diphenylmethylbis Diphenylmethylbis (trimethylcyclopenta Diphenylmethyl-bis (dimethylamino) hafnium dimethyl, diphenylmethylbis (5-dimethylamino-1-indenyl) hafnium dimethyl, diphenylmethylbis 1-indenyl) hafnium dimethyl, diphenylmethylbis (5-diphenylphosphino-1-indenyl) hafnium dimethyl, diphenylmethyl (1-dimethylamino-9-fluorenyl) (1- cyclopentadienyl) hafnium dimethyl, diphenylmethyl (4-butylthio-9-fluorenyl) (1-cyclopentadienyl) hafnium dimethyl, diphenylmethyl (9- Cyclopentadienyl) hafnium dimethyl, diphenylmethylbis (9-fluorenyl) hafnium dimethyl, diphenylsilylbis (1-cyclopentadienyl) zirconium dimethyl, diphenylsilylbis (1-indenyl) zirconium dimethyl, (4-methyl-1-indenyl) zirconium dimethyl, diphenylsilylbis (5-methyl-1-indenyl) zirconium dimethyl, diphenylsilylbis One- (4-phenyl-1-indenyl) zirconium dimethyl, diphenylsilylbis (6-methyl-1-indenyl) zirconium dimethyl, diphenylsilylbis Indenyl) zirconium dimethyl, diphenylsilylbis (5-methoxy-1-indenyl) zirconium dimethyl, diphenylsilylbis (2,3- (4,7-dimethoxy-1-indenyl) zirconium dimethyl, diphenylsilylbis (trimethylcyclopentadienyl) zirconium dimethyl, diphenylsilylbis (Dimethylamino) -1-indenyl) zirconium dimethyl, diphenylsilylbis (6-dipropylamino-1-indenyl) zirconium dimethyl, diphenylsilylbis Indenyl) zirconium dimethyl, diphenylsilylbis (5-diphenylphosphino-1-indenyl) zirconium dimethyl, diphenylsilyl (1-dimethylamino-9-fluorenyl) Zirconium dimethyl) diphenylsilyl (4-butylthio-9-fluorenyl) (1-cyclopentadienyl) zirconium dimethyl, diphenylsilyl (9-fluorenyl) (1-cyclopentadienyl) zirconium (1-cyclopentadienyl) hafnium dimethyl, diphenylsilylbis (1-indenyl) hafnium dimethyl, diphenylsilylbis (4-methylcyclopentadienyl) zirconium dimethyl, diphenylsilylbis , 5,6,7-tetrahydro-1-indenyl) hafnium dimethyl, diphenylsilylbis (4-methyl-1-indenyl) hafnium dimethyl, diphenylsilylbis Diphenylsilylbis (4-phenyl-1-indenyl) hafnium dimethyl, diphenylsilylbis (7-methyl-1-indenyl) hafnium dimethyl, diphenylsilylbis (5-methoxy-1-indenyl) hafnium dimethyl, diphenylsilylbis (2,3-dimethyl-1-indenyl) hafnium dimethyl, diphenylsilylbis -1-indenyl) hafnium dimethyl, Diphenylsilylbis (5-dimethylamino-1-indenyl) hafnium dimethyl, diphenylsilylbis (trimethylcyclopentadienyl) hafnium dimethyl, diphenylsilylbis Dimethyl dimethyl diphenyl silylbis (6-dipropylamino-1-indenyl) hafnium dimethyl, diphenyl silylbis (4,7-bis (dimethylamino) -1-indenyl) hafnium dimethyl, diphenyl silylbis Diphenylsilyl (1-dimethylamino-9-fluorenyl) (1-cyclopentadienyl) hafnium dimethyl, diphenylsilyl (4-butylthio-9 Dimethylcyclopentadienyl) hafnium dimethyl, diphenylsilyl (9-fluorenyl) (1-cyclopentadienyl) hafnium dimethyl, diphenylsilylbis (9-fluorenyl) hafnium dimethyl And the like.

The "dimethyl" moieties of each of the titanium, zirconium and hafnium compounds enumerated above may also be substituted with one or more substituents selected from the group consisting of -dichloro, -dibromo, -diiodide, -diethyl, -dibutyl, -dibenzyl, 2-butene-1,4-diyl, -s-trans-eta4-1,4-diphenyl-1,3-butadiene, -s- trans- Methyl-1,3-pentadiene, -s-trans-eta4-1,4-dibenzyl-1,3-butadiene, -s- trans-eta4-2,4-hexadiene, -1,4-bis (trimethylsilyl) -1,3-butadiene, -s-trans- Butadiene, -s-cis-? 4-1,4-diphenyl-1,3-butadiene, -s-cis-? 4-3-methyl-1,3-pentadiene, -S-cis-? 4-2,4-hexadiene, -s-cis-? 4-1,3-pentadiene, -s-cis- -T-1,4-butadiene, -s-cis-? 4-1,4-bis (trimethylsilyl) -1,3-butadiene and the like are also examples of metallocene compounds.

The non-halogenated monocyclopentadienyl group-4 metal compound (B) among the catalyst components may be represented by the following general formula (3).

...... (3)

(3)

Wherein x is 0, 1, 2, 3 or 4, y is 0 or 1, R is hydrogen, a hydrocarbon group having 1 to 20 carbon atoms, a silyl group, a germyl group, a cyano group, And Y 'represents -O-, -S-, -NR * -, or -PR * -, wherein R * represents hydrogen, a C1-12 hydrocarbyl group having 1 to 20 carbon atoms, A halogenated alkyl group having 1 to 8 carbon atoms, a halogenated aryl group having 6 to 20 carbon atoms, or a multifunctional group thereof), Z represents SiR * ₂ , Si (OR * ) R *, Si (OR * ) 2, Si (NR *) R *, Si (NR *) 2, CR * 2, SiR * 2 SiR * 2, CR * 2 CR * 2, CR * = CR *, CR * ₂ SiR * ₂ or GeR * ₂ , R * is as defined above, L is independently a hydrocarbon group of 1 to 30 carbon atoms, and M represents Ti or Zr.

Examples of the (B) non-halogenated monocyclopentadienyl Group 4 metal compound include [(Nt-butylamide) (tetramethyl-? 5-cyclopentadienyl) -1,2-ethanediyl] titanium dimethyl, (Tetramethyl-? 5-cyclopentadienyl) -dimethylsilane] titanium dimethyl, [(N-methylamide) (tetramethyl-? 5-cyclopentadienyl) -1,2-ethanediyl] (Tetramethyl-? 5-cyclopentadienyl) -dimethylsilane] titanium dimethyl, [(N-phenylamide) (tetramethyl-? 5-cyclopentadienyl) -dimethylsilane] [(N-benzylamide) (tetramethyl-? 5-cyclopentadienyl) -dimethylsilane] titanium dimethyl, [(N-methylamido) (eta 5 -cyclopentadienyl) -1,2-ethanediyl [(N-butylamido) (η5-indenyl) -dimethylsilane] titanium dimethyl, [(N-methylamido) (η5-cyclopentadienyl) -dimethylsilane] titanium dimethyl, Benzylamide) (? 5-phosphorous Dimethylsilyltrimethylcyclopentadienyl-tert-butylamidozirconium dimethyl, dimethylsilyl tert-butylcyclopentadienyl-tert-butylamidozirconium dimethyl, dimethylsilyltrimethylsilylcyclopentadienyl dimethylsilyltrimethylcyclopentadienyl- Diethyl-tert-butylamidozirconium dimethyl, dimethylsilyl tetramethylcyclopentadienyl-phenylamidozirconium dimethyl, methylphenylsilyltetramethylcyclopentadienyl-phenylamidozirconium dimethyl, methylphenylsilyl tert-butylcyclopentadienyl butylamido zirconium dimethyl, dimethylsilyl tetramethylcyclopentadienyl-pn-phenylamidozirconium dimethyl, etc., and also the "dimethyl" portion of each of the titanium and zirconium compounds enumerated above as - diethyl, dibutyl , -Dibenzyl, -diphenyl, and the like, and at least one selected from the above can be used There.

The catalyst of the present invention uses the metallocene compound as described above, but may contain at least one metallocene compound (A) as described above. In addition, additional catalysts and, if necessary, further catalyst components other than the metallocene catalyst component according to the present invention may be further included.

(A: B) molar ratio of the metallocene compound (A) used in the present invention to the non-halogenated monocyclopentadienyl Group 4 metal compound (B) is 0.01: 1 to 100: 1. When the molar ratio is 0.01: 1 or less, the polymerization activity is significantly lowered. When the molar ratio is 100: 1 or more, it is difficult to obtain the effect of increasing the polymerization activity to be achieved in the present invention.

Among the catalyst components of the present invention, (C) the activating cocatalysts component comprises aluminoxane, an organoaluminum compound or an ionizing activator.

Wherein the aluminoxane comprises a straight chain and / or cyclic alkyl aluminoxane oligomer, and when the aluminoxane is a straight chain aluminoxane oligomer, it is represented by the formula R- (Al (R) -O) _n -AlR ₂ , In the case of a noxic acid oligomer, it is represented by the formula (-Al (R) -O-) _m , wherein R is an alkyl group having 1 to 8 carbon atoms, preferably methyl, and n is 1 to 40, 20, and m is 3 to 40, preferably 3 to 20. The aluminoxane is a mixture of oligomers having a very large molecular weight distribution, and usually has an average molecular weight of about 800 to 1200. The aluminoxane solution may contain an aromatic hydrocarbon, an aliphatic hydrocarbon or an aliphatic cyclic hydrocarbon as a solvent, and is preferably used mainly as a solution in toluene. As an example thereof, 10% or 30% methyl aluminoxane produced by Albemarle .

As the organic aluminum compound is represented by the general formula AlR _n X _(3-n) alkyl aluminum compounds represented by (wherein, R is an alkyl group of carbon number 1 ~ 16, X is a halogen atom, a 1≤n≤3) Can be used. Specific examples of the alkylaluminum compound include trialkylaluminums such as triethylaluminum, trimethylaluminum, trinormalpropylaluminum, trinormalbutylaluminum, triisobutylaluminum, trinormalhexylaluminum, trinormaloctylaluminum, tri-2-methylpentyl Aluminum and the like are used. Particularly preferably, triisobutylaluminum, triethylaluminum, trinormalhexylaluminum or trinormaloctylaluminum is used.

The ionization activator is necessary for ionizing the neutral metallocene compound and may be selected from the compounds represented by the following general formula (4), (5) or (6).

B (R ^a ) _{3 -} (4)

[R ^b ] ⁺ [BR ^a ] ^{- -} (5)

[R ^c -H] ⁺ [BR ^a ] ^{- -} (6)

In the general formulas (4), (5) and (6), B is a boron atom, R ^a is phenyl or phenyloxy, the phenyl or phenyloxy is optionally substituted by a fluorine atom, Alkyl, or alkoxy having 1 to 20 carbon atoms which is unsubstituted or substituted by fluorine atom (s), R ^b is a cycloalkyl radical having 5 to 7 carbon atoms, (C 1 -C 20) alkyl (C6~C20) aryl radical, or (C6~C30) aryl (C1~C20) alkyl radicals, [R ^c -H] ⁺ is an ammonium or phosphonium substituted by 1 to 3 (C1~C20) alkyl phosphonium Ions.

Specific examples of the boron compounds represented by the general formulas (4), (5) and (6) include trimethylammoniumtetra (phenyl) boron, triethylammoniumtetra (phenyl) boron, tripropylammoniumtetra Boron, trimethylammonium tetra (p-tolyl) boron, trimethylammonium tetra (o, p-dimethylphenyl) boron, trimethylammonium tetra (ptrifluoromethylphenyl) boron, tributylammonium tetra (Phenyl) boron, N, N-diethylamidinium tetra (phenyl) boron, N, N-dimethylamidinium tetra (pentafluorophenyl) boron, (Pentafluorophenyl) boron, trimethylphosphonium tetra (phenyl) boron, triphenylphosphonium tetra (phenyl) boron, trimethylphosphonium tetra (pentafluorophenyl) boron, Boron, triphenylphosphonium tetra (pentafluorophenyl) boro , It can be included such as triphenyl car I Titanium tetra (p- trifluoromethylphenyl) boron, triphenyl car I Titanium tetra (penta-trifluoro-phenyl) boron, trityl tetra (penta-trifluoro-phenyl) boron.

Among the catalyst components of the present invention, the carrier (D) is a solid particulate porous material, preferably an inorganic material such as silicon and / or aluminum oxide, and most preferably spherical particles, for example, Most preferred are silica in the form of particles and OH groups or other functional groups containing active hydrogen atoms. The carrier preferably has an average particle size of 10 to 250 占 퐉, preferably an average particle size of 10 to 150 占 퐉, an average diameter of 50 to 500 占 and a micropore volume of 0.1 to 10 ml / g, 0.5 to 5 ml / g, and the surface area of the carrier is 5 to 1,000 m 2 / g, preferably 50 to 600 m 2 / g.

When silica is used as the carrier, at least a part of the active hydroxy [OH] group should be used. The concentration of the hydroxy group is preferably 0.5 to 2.5 mmole or more per 1 g of the silica, more preferably 0.7 to 1.6 mmole / g, If it is less than 0.5 mmole, the amount of methylaluminoxane supported decreases and the activity decreases, which is undesirable. If it exceeds 2.5 mmol, the catalytic component becomes inactive due to OH, which is not preferable.

The hydroxyl groups of the silica can be detected by IR spectroscopy, and the determination of the hydroxyl group concentration on the silica is carried out by bringing the silica sample into contact with methylmagnesium bromide and measuring the amount of methane foaming (by pressure measurement).

As the silica having the [OH] concentration and the physical properties suitable for the present invention, a silica having a surface area of 300 m &lt; 2 &gt; / g and a pore volume of 1.6 ml / XPO-2410, XPO-2411 and XPO-2412 available from Davison Chemicals Division of Grace &amp; Company, Inc., and dehydrated silica such as Davision 948, 952 and 955 can be used. The desired concentration of [OH] can be used.

The catalyst used in the production of the ethylene copolymer of the present invention is prepared by carrying the above components (A), (B) and (C) onto a carrier which is a component (D) When the silica is used as the carrier, the hydroxyl group of the silica is reacted with an aluminoxane under anhydrous condition free of oxygen to carry aluminoxane to form a metal It serves to protect the metallocene, which is likely to lose its activity due to its sensitivity to external catalyst poisons while providing a site to support the catalyst. Therefore, the higher the amount of supported aluminoxane, the higher the loading of metallocene, the higher the probability of not poisoning by the external catalyst poison, and the higher the activity.

Preparation of Ethylene Copolymer

The ethylene copolymer according to the present invention is characterized in that the main catalyst is the metallocene catalyst component (A), the non-halogenated monocyclopentadienyl Group 4 metal compound (B), the activating cocatalysts component (C) And (D) a metallocene supported catalyst comprising a carrier component, in the presence of a catalyst for gas phase polymerization comprising hydrogen, ethylene and a comonomer.

As an embodiment, the ethylene copolymer according to the present invention can be produced by using the metallocene catalyst in the presence of a hydrocarbon selected from hydrocarbons such as propane, isobutane, hexane, heptane and the like as a reaction solvent, And a comonomer for gas phase polymerization.

In the production of the ethylene copolymer according to the present invention, the hydrogen contained in the gas phase polymerization composition is used for controlling the molecular weight of the resulting polymer, and the content ratio of hydrogen to ethylene is in the range of molar ratio of hydrogen / Is in the range of 0.0005 to 0.005, preferably 0.0008 to 0.0015. When the hydrogen / ethylene molar ratio is less than 0.0005 or more than 0.005, the molecular weight of the polymer is too low or too high, making it difficult to apply the product to a product.

Further, in the process for producing an ethylene copolymer according to the present invention, the comonomer contained in the gas phase polymerization composition is preferably selected from the group consisting of propylene, 1-butene, 1-hexene, 4-methyl- -Olefin is preferable, and the content ratio of the comonomer and the ethylene is 0.005 to 0.05, preferably 0.008 to 0.025 in a molar ratio of comonomer / ethylene. When the molar ratio of comonomer / ethylene is less than 0.005 or exceeds 0.025, a desired level of copolymer can not be obtained. This is because, when the content of the comonomer contained in the gas phase polymerization composition is too small, the crystallinity is partially increased in the copolymer during processing and the transparency is decreased. On the other hand, when the content of the comonomer is too high, the softening temperature is lowered and the reaction stability in the gas phase polymerization reactor is lowered.

In the process for preparing an ethylene copolymer according to the present invention, it is preferable that the metallocene supported catalyst is combined with at least one activating agent in addition to the activating catalyst component used in the catalyst preparation to form an ethylene polymerization catalyst system. Preferred activators include alkyl aluminum compounds such as diethyl aluminum chloride, aluminoxanes, modified aluminoxanes, neutral or ionic ionizing activators, non-coordinating anions, non-coordinating Group 13 metals or metaloid anions, borane, have.

Examples of the alkylaluminum compound usable as the activator include compounds represented by the general formula AlR _n X _(3-n) (wherein R is an alkyl group having 1 to 16 carbon atoms and X is a halogen element and 1? _{N? 3} ) May be used. Specific examples of the alkylaluminum compound include trialkylaluminums such as triethylaluminum, trimethylaluminum, trinormalpropylaluminum, trinormalbutylaluminum, triisobutylaluminum, trinormalhexylaluminum, trinormaloctylaluminum, tri-2-methylpentyl Aluminum and the like are used. Particularly preferably, triisobutylaluminum, triethylaluminum, trinormalhexylaluminum or trinormaloctylaluminum is used.

The alkylaluminum compound may have, depending on the desired polymer properties,

100 Alkyl aluminum compound / transition metal in the main catalyst &lt; = 1000

Is preferably used at the time of gas phase polymerization,

300 Alkyl aluminum compound / transition metal in main catalyst &lt; 500

Is more preferably used at the time of gas phase polymerization.

If the molar ratio of the transition metal in the alkyl aluminum compound / main catalyst is less than 100, a sufficient polymerization activity can not be obtained. On the other hand, if it exceeds 1000, the polymerization activity becomes rather low.

Alternatively, the alkylaluminum compound may have, depending on the desired polymer properties,

10? Al / gas phase reactor bed (BED) amount? 200

More preferably,

30? Al / gas phase reactor bed amount? 50

(Ppm). &Lt; / RTI &gt;

If the amount of the Al / gas phase reactor bed is less than 10 ppm, sufficient polymerization activity can not be obtained and the homogeneity of the reaction can not be ensured. Hence, reaction temperature hunting occurs and causes instability. When the amount exceeds 200 ppm, There is an adverse effect of lowering the activity.

(N-butyl) ammonium tetrakis (pentafluorophenyl) boron or tris (pentafluorophenyl) boron, which ionizes the neutral metallocene compound and / or the use of aluminoxane or modified aluminoxane as the activator. It is also within the scope of the present invention to use a perfluorophenylboron metalloid precursor. Other compounds useful as activators include triphenylboron, triethylboron, tri-n-butylammonium tetraethylborate, triarylborane and the like. Aluminate salts are also useful activator compounds.

In the preparation of the ethylene copolymer according to the invention, the polymerization reaction is carried out in the absence of a hydrocarbon solvent, preferably at a temperature of from 60 to 120 캜, more preferably from 65 to 100 캜, even more preferably from 70 to 80 캜, Preferably at a pressure of 2 to 40 atm, more preferably at a pressure of 10 to 30 atm.

If the polymerization temperature in the gas phase fluidized bed reactor is less than 60 캜, sufficient polymerization efficiency can not be obtained, and if it exceeds 120 캜, a polymer mass tends to be generated. If the operating pressure in the gas phase fluidized bed reactor is less than 2 atmospheres, the heat capacity per unit volume becomes too low to obtain sufficient polymerization efficiency. If the operating pressure exceeds 40 atm, control of the reaction becomes difficult and the reactor is subjected to excessive load.

In the production of the ethylene copolymer according to the present invention, it is preferable to further inject an antistatic agent for prevention of sheet formation by static electricity and for stabilizing the reaction, in addition to the above-mentioned catalyst components.

The antistatic agent suppresses fouling and aggregation, but when used in excess, it reacts with the metallocene catalyst to reduce the activity of the catalyst, to produce low molecular weight polymers, and to inhibit the insertion of alpha olefins. Therefore, it is preferable to appropriately adjust the ratio of the content of the activator in the bed and the content of the antistatic agent in the bed, which can minimize the generation of static electricity and the decrease in catalyst activity. The antistatic agent is a material capable of restricting the phenomenon related to static electricity through a unique functional group. It can prevent the aggregation phenomenon between the polyolefin particles and can prevent the fouling of the wall surface of the reactor and the dispersion plate, the circulating gas transfer path, Can be prevented. Such antistatic agents include alkoxylated amines, alkoxylated amides, preferably non-volatile liquids composed of long chain diethanolamines. At least one metal salt of an organic carboxylic acid such as a fatty acid having 8 to 30 carbon atoms may be used. The molecular weight is in the range of 150 to 1,200, and the metal includes an alkali metal and an alkaline earth metal. Commercially available antistatic agents include ARMOSTAT 400, ARMOSTAT 1800 from AKZO NOBEL or ATMER 163 and AS 990 from CIBA GEIGY. Preferred examples of the antistatic agent include n, n-bis (2-hydroxyethyl) amines having a structure of RN (C ₂ H ₄ OH) ₂ (wherein R is an alkyl group having 12 to 16 carbon atoms).

The antistatic agent is preferably used in polymerization at the following contents (ppm) on the basis of the fluidized bed:

10? Antistatic agent compound / gas phase reactor bed amount? 200

More preferably,

30? Antistatic agent compound / gas phase reactor bed amount? 80.

If the amount of the antistatic agent compound / bed is less than 10 ppm, the effect of removing the static electricity is insufficient and the stability of the reaction can not be ensured. If the amount exceeds 200 ppm, the catalyst is deformed and the polymerization activity is lowered. The effect of such an antistatic agent will vary depending on the kind and content of the activating agent used in the polymerization reaction system.

The metallocene supported catalyst component which can be used as the main catalyst in the preparation of the ethylene copolymer of the present invention can be used in the prepolymerized state with ethylene or an alpha -olefin before being used as a component in the polymerization reaction. The prepolymerization can be carried out in the presence of a hydrocarbon solvent such as hexane at a sufficiently low temperature and in the presence of the catalyst component and an organoaluminum compound such as triisobutylaluminum under ethylene or alpha-olefin pressure conditions. Pre-polymerization helps wrap the catalyst particles around the polymer to maintain the catalyst shape and improve the shape of the polymer after polymerization. The weight ratio of polymer / catalyst after pre-polymerization is usually from 0.1: 1 to 200: 1. Preferred organometallic compounds are trialkylaluminums having alkyl groups with 1 to 6 carbon atoms, such as triethylaluminum and triisobutylaluminum, and mixtures thereof. In some cases, an organoaluminum compound having at least one halogen or hydride group such as ethylaluminum dichloride, diethylaluminum chloride, ethylaluminum sesquichloride, diisobutylaluminum hydride and the like can be used.

The ethylene copolymer produced according to the method of the present invention exhibits a low resin pressure and motor load and excellent processing speed in pipe extrusion molding, and is excellent in workability.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic view of a circulating fluidized bed reactor used in polymerization in an embodiment of the present invention. FIG.
2A shows measured values of the storage elastic modulus (G ') and the loss elastic modulus (G ") at 190 ° C.
2B is a graph showing the complex elastic modulus (G *) from the results of measured values of storage modulus (G ') and loss modulus (G ") at 190 ° C.
3 is a diagram showing an example in which a phase angle value shift? According to a complex elastic modulus at 190 占 폚 is plotted.
4 is a diagram showing an example of calculating the phase angle value? _C to the complex elastic modulus at 190 占 폚.
FIG. 5 shows the complex elastic modulus (G *) versus phase angle value (?) Curves of Examples 1 to 3 and Comparative Examples 1 and 2. The critical phase angle value is an intersection value of two slopes as described above.
6 is a graph showing the GPC-IR curve and the bioCD index (BOCDI) of Example 2. Fig.
7 is a graph showing a GPC-IR curve and a bio-CD index (BOCDI) of Comparative Example 2. Fig.

Hereinafter, the present invention will be described in more detail with reference to examples. However, these embodiments are for illustrative purposes only, and the present invention is not limited to these embodiments.

Manufacturing example

(Tt-butylamido) - (tetramethylcyclopentadienyl) -titanium dibenzyl: Me ₂ Si (NtBu) (Cp *) Ti (Bn ) ₂ ) Synthesis of

5.2 mmol of Ti (CH ₂ Ph) ₄ and _4.0 mmol of dimethylsilylene (t-butylamido) - (tetramethylcyclopentadienyl) (Dimethylsilylene (t-butylamido) Schlenk Line) was completely dissolved by injecting 50 mL of purified toluene. The temperature of the reactor in which the sunlight was shut off was raised to 60 DEG C and the reaction was carried out for 12 hours.

The reaction was dried in vacuo. The dried reaction product was again extracted with pentane and then vacuum dried to obtain final Me ₂ Si (NtBu) (Cp *) Ti (Bn) ₂ . The yield was > 90%. The structure of the compound was confirmed by ¹ H NMR.

^{1 H NMR (400MHz, C6D6)} 7.16 (Ph, 4H, d), 6.95 (Ph, 4H, t), 6.90 (Ph, 2H, t), 2.58 (CH 2 Ph, 2H, d), 2.25 (CH 2 Ph, 2H, d), 1.81 (C 5 Me 4, 6H, s), 1.63 (C 5 Me 4, 6H, s), 1.43 (tNBu, 9H, s), 0.41 (SiMe 2, 6H, s)

Example  One

[ Preparation of metallocene supported catalyst]

500 g of dehydrated silica was weighed under anhydrous condition under the trade name XPO-2402 (Grace, USA, average particle size ~ 50 μm, surface area 300 m 2 / g, micropore volume 1.6 ml / g, OH concentration 1 mmol / g) And the mixture was stirred in a slurry state. This was injected into a 10 L reactor equipped with a stirrer and a cooling condenser. A methylaluminoxane solution (10 wt%) (methylaluminoxane / g silica = 15 mmol / g silica) was quantified in a measuring cylinder and then injected into the reactor. Thereafter, the reactor temperature was elevated to 110 DEG C with stirring. The support reaction was carried out at this temperature for 90 minutes. After completion of the reaction, the reaction was allowed to stand and the upper solution was decanted. 500 mL of toluene solution was injected to wash the reaction product, the reaction solution was allowed to stand, and the upper solution was drained. This operation was repeated twice.

(Et (THI) ₂ ZrCl ₂ ) [metallocene (Et (THI) ₂ ZrCl ₂ ) which is a quantified metallocene catalyst component, ethylene bis (4,5,6,7-tetrahydridoindenyl) zirconium dichloride / Si = 100μmol / g silica; and the manufacture example of the non-composite in-halogenated monocyclopentadienyl Group 4 metal compound _{(Me 2 Si (NtBu) (} Cp *) Ti (Bn) 2) [Me 2 Si ( NtBu) (Cp *) Ti (Bn) ₂ / silica = 150 占 퐉 ol / g silica] was diluted in 200 ml of toluene at room temperature to prepare a solution.

This was injected into the reactor, the temperature was raised to 50 DEG C, and the support reaction was allowed to proceed for 6 hours at this temperature. After the completion of the reaction, the reaction product was transferred to a Schlenk vessel, and then the upper solution was decanted. 500 mL of toluene was added to the reaction mixture, and the reaction mixture was allowed to stand. Such washing was carried out three times. The resulting catalyst was then washed with purified hexane and then dried under mild vacuum to give a catalyst in the form of Free Flowing Powder.

[Polymerization method]

The polymerization process was carried out in a continuous-fluidized bed reactor as in Fig. The fluidized bed consisted of polymer particles. The gas-phase feed stream of ethylene and hydrogen and monomers were introduced into the recycle gas line below the reactor bed. 1-Hexene was used as the comonomer. The flow rates of each of ethylene, hydrogen and comonomers were adjusted to maintain the desired constant composition. The ethylene concentration was adjusted to maintain a constant ethylene partial pressure. Hydrogen was adjusted to maintain a constant hydrogen to ethylene molar ratio. The concentration of all gases was measured by an on-line gas chromatograph such that the composition of the recycle gas stream was relatively constant. The reaction bed consisting of the polymer particles was kept fluidized by the continuous flow of the supplemental feed and the recirculating gas through the reaction zone. The reactor was operated at a total pressure of 19.2 Kgf / cm ² . The reaction was initiated by injecting the supported metallocene catalyst prepared under the above conditions at a constant rate. Tri-n-octylaluminum, an alkyl aluminum compound, was diluted with hexane as an activating agent for initiating the reaction at the same time as the catalyst was injected, 30 ppm was injected as a reference. In order to stabilize the reaction, antistatic agent AS990 was diluted in oil and injected so as to maintain a content of 50 ppm in the bed. In order to keep the reactor temperature constant as the polymerization progresses, the temperature of the recirculating gas is continuously increased or decreased while the recirculating gas passes through the heat exchanger so as to control the change in the exothermic rate caused by the polymerization. The fluidized bed was maintained at a constant height by withdrawing a portion of the bed at the same rate as the product formation rate. The gas phase polymerization conditions were as shown in Table 1, and the polymerization results are shown in Table 1.

[Analysis of physical properties of polymer]

The polymer obtained by the above polymerization method was subjected to the following analysis.

(1) Melt flow rate ratio (MFRR): Calculated as a ratio of the melt index under a load of 21.6 kg and a load of 2.16 kg at 190 캜.

(2) Molecular weight distribution: Calculated as the ratio (Mw / Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn) measured from Gel Permeation Chromatography (GPC).

(3) Zero Shear Viscosity: Calculated by measuring the dynamic fluidity data using a frequency sweep method at 190 ° C using a Rheometric ARES flow meter. The spacing in the parallel plate structure is 2 mm, the plate diameter is 25 mm, and the deformation amplitude is 10%. The frequency was measured in the range of 0.05 to 300 rad / sec. Zero shear viscosity was calculated using the Carraeu Model.

(4) Total point viscosity ratio (SHI): Calculated from the ratio of the complex viscosity at a frequency of 0.1 rad / sec to the complex viscosity at a frequency of 100 rad / sec measured from ARES.

(5) Critical phase angle value (? C)

First, dynamic fluidity data was measured by frequency sweep method using TA Instruments ARES equipment. When a plot of the phase angle value shift (delta) and the complex elastic modulus (G *) is made from the measurement data, the linear structure PE and the LCB structure PE exhibit different behaviors, and the PE of the LCB structure exhibits the phase angle value In the complex elastic modulus (G *) plot, an inflection point at which the slope of the graph changes occurs, which is referred to as a critical phase angle value (δ _C ). Generally, it is known that the critical phase angle value (δ _C ) correlates with the content of LCB, and the larger the LCB, the lower δ _C is.

The critical phase angle value (δc) calculation method is calculated from the dynamic fluidity data measured as follows.

① Complex Elastic Modulus (Complex Elastic Modulus) Plot Calculation

G * (complex elastic modulus) is calculated from the results of the storage modulus G '(loss modulus) and loss modulus G' (loss modulus) using the following equation (1) and plotted as shown in FIG.

② Phase angle shift (δ) plot calculation

The dynamic test method using the ARES of the strain control type applies the oscillation strain to the polymer melt with a sin function as shown in FIG. 3, and the stress at that time a combination of elastic in-phase characteristics and viscous out-of-phase is used as a method of measuring a stress and a correlation between stress and deformation. As shown in Fig. The G * (complex elastic modulus) obtained in the above is plotted as the phase angle value shift (?) To obtain the result shown in FIG.

FIG. 3 is a plot of the linear structure PE and the LCB structure PE, which shows the difference depending on the structure.

③ Calculate the critical phase angle value (δ _C )

The inflection point at which the slope of the graph changes in the curve of the complex elastic modulus (G *) versus the phase angle value (?) Becomes the critical phase angle value? _C. As shown in FIG. 4, a slope is obtained by designating a section that is a straight line from the lower G * value. After passing the inflection point again, specify the straight line to obtain the slope. Obtain the slope of the two sections and obtain the critical phase angle value (δ _C ) at the intersection.

(6) Broad Orthogonal Composition Distribution Index (BOCDI)

GPC-IR, which is equipped with FTIR (Fourier Transform Infrared Spectroscopy), is used to analyze and calculate the comonomer in the GPC used for the above molecular weight distribution analysis. From the results of GPC-IR analysis, the SCB content of the upper 80% of the measured molecular weight (high molecular weight point) and the SCB content of the lower 20% point (low molecular weight point) were measured based on the weight average molecular weight (Mw) And calculates a bio-CD index.

[Pipe forming]

Using the polymer obtained in the above polymerization experiment, pipe molding was carried out under the following conditions, and the characteristics of the produced pipe are shown in Table 3.

Pipe Machine: IKEGAI 50mm Pipe M / C

Pipe processing temperature: 180 ~ 200 ℃

Pipe sample dimensions: Outer diameter 32 ~ 33mm, thickness 2.9 ~ 3.1mm

Example  2

In the same manner as in Example 1, except that ethylene bis (4,5,6,7-tetrahydridenyl) zirconium dichloride (Et (THI) ₂ ZrCl ₂ ) was used as the metallocene catalyst component, bis Cyclopentadienyl) zirconium dichloride was used under the same conditions as in Example 1 to prepare a catalyst. The polymerization was carried out under the same conditions as in Example 1.

Example  3

In the same manner as in Example 1, except that ethylene bis (4,5,6,7-tetrahydridoindenyl) zirconium dichloride (Et (THI) ₂ ZrCl ₂ ) was used as the metallocene catalyst component, bis -3-methylcyclopentadienyl) zirconium dichloride was used under the same conditions as in Example 1 to prepare a catalyst, and polymerization and pipe molding were carried out under the same conditions as in Example 1.

Comparative Example  1-3

For comparison of pipe properties and workability, conventional commercial product linear medium density polyethylene made using Ziegler-Natta (Z-N) and metallocene catalysts were selected.

Comparative Example 1: Domestic marketed MDPE (medium density polyethylene) having MI = 0.73 density = 0.938

Comparative Example 2: Domestic commercial MDPE (medium density polyethylene) having MI = 0.56 density = 0.936

Comparative Example 3: Domestic marketed MDPE (medium density polyethylene) having MI = 0.62 density = 0.934

Item unit Example 1 Example 2 Example 3 polymerization
Condition catalyst - Metallocene Metallocene Metallocene Polymerization temperature ℃ 80 80 80 Polymerization pressure kg / cm ² 19.2 19.2 19.2 Ethylene (C2) mol% 35 35 35 Hydrogen (H ₂ ) mol% 0.05 0.05 0.05 H2 / C2 - 0.00035 0.00018 0.00025 1-Hexene mol% 0.45 1.1 0.89 Bed amount kg 70 70 70 Residence time hr 12 12 12 output kg / hr 6 6 6 Apparent density g / cc 0.48 0.48 0.48 polymer Melt Index (MI) g / 10 min 0.67 0.71 0.72 density g / cm ³ 0.937 0.937 0.937 MFRR (MI ₂₁ / MI ₂ ) - 32 31 33 Molecular weight distribution - 3.2 2.9 3.4 The zero shear viscosity (η ₀ ) poise 9.7x10 ⁵ 8.9x10 ⁵ 9.9x10 ⁵ The forward point ratio (SHI) - 14.0 12.2 15.2 Critical Phase Angle Value
(? c) Degree 62 62 57 The flow activation energy (Ea, kJ / mol) 48 46 50 BIO CD Index (BOCDI) 2.8 2.5 3.7

Item unit Comparative Example 1 Comparative Example 2 Comparative Example 3 Melt Index (MI) g / 10 min 0.73 0.57 0.62 density g / cm ³ 0.938 0.936 0.934 MFRR (MI ₂₁ / MI ₂ ) - 38.5 32.5 23.5 Molecular weight distribution - 3.9 3.4 3.8 The zero shear viscosity (η ₀ ) poise 2.2x10 ⁵ 11.5x10 ⁵ 1.8x10 ⁵ The forward point ratio (SHI) - 7.8 9.7 5.4 Critical Phase Angle Value
(? c) Degree ND 62 ND Flow activation energy
(Ea, kJ / mol) 28 48 27 BIO CD Index (BOCDI) 2.7 0.38 -0.12

(Note) ND: Not Detected

Item Exam conditions Example 1 Example 3 Comparative Example 1 Comparative Example 2 Comparative Example 3 Environmental stress uniformity (ESCR) FNCT, F50 (hr) > 1000 > 1000 > 1000 > 1000 > 1000 Creep resistance 95 C, 3.5 Mpa > 1200 > 1200 > 1200 > 1200 > 1200 RPM ^- 60 60 60 60 60 Motor load A 44 44 45 47.5 52 Processing speed m / min 0.60 0.62 0.57 0.56 0.55 Pipe Appearance - Good Good Good Good Good

The ethylene copolymer according to the present invention exhibits a relatively narrow molecular weight distribution as shown in Table 1 and has a long chain branch (LCB) as shown by the critical phase angle value and the flow activation energy value. As for the distribution of comonomers, it can be seen that, as shown in the BIODY index, more molecules are distributed in a larger molecular weight depending on the molecular weight. The molecular properties of the ethylene copolymer structure of the present invention are also evident in pipe workability and pipe properties as shown in Table 3 above. That is, despite the relatively narrow molecular weight distribution, it shows low motor load and high processing speed in the pipe machining, and it shows that the pipe has excellent physical properties. This is because the narrow molecular weight distribution is expected to lead to superior physical properties of the pipe, and the long-chain branch (LCB) is overcome to overcome the problem of narrow molecular weight distribution, thereby exhibiting excellent pipe workability.

The above results are also shown in comparison with the comparative examples in Table 2. &lt; tb &gt;&lt; TABLE &gt; Compared with Comparative Examples 1 and 3, the results of Examples show good workability in spite of a relatively narrow molecular weight distribution. Compared with Comparative Example 2, the high bio-indexes result in low motor load and excellent processing speed Show.

1. Reactor upper extension
2. Fluidized bed
3. Heat exchanger
4. Compressor

Claims (10)

An ethylene copolymer prepared by copolymerizing ethylene and an alpha-olefin using a metallocene catalyst and having the following characteristics:
1) a melt flow index of 0.2 to 2.0 g / 10 min (190 캜, 2.16 Kg load)
2) a density of 0.930 to 0.955 g / mL,
3) a molecular weight distribution (weight average molecular weight / number average molecular weight) of 2.5 to 4.0,
4) the bio-CD index is > 0.5, and
5) Critical phase angle value (critical phase angle value,? C) is <70;
The metallocene catalyst comprises (A) a metallocene catalyst component, (B) a non-halogenated monocyclopentadienyl Group 4 metal compound, (C) an activating co-catalyst component and (D) a carrier component,
Wherein the metallocene catalyst component (A) in the metallocene catalyst is a dicyclopentadienyl metallocene of the following general formula (1) or a bridged metallocene of the general formula (2)
(CpR _n ) (CpR ' _m ) ML _q (1)
Wherein Cp is cyclopentadienyl, indenyl, or fluorenyl,
R and R 'are each independently hydrogen, alkyl, alkyl ether, allyl ether, phosphine or amine,
L represents alkyl, allyl, arylalkyl, amide, alkoxy or halogen,
M represents a transition metal of Group 4 or Group 5 of the periodic table,
n is an integer satisfying 0? n <5, m is 0? m <5, q is 1? q? 4;
Q (CpR _n ) (CpR ' _m ) ML _q (2)
Wherein Q is a bridging bond between the C rings, and R 1, R 2, R 3, R 4, N is an integer satisfying 0? N <4, m is 0? M <4, q is 1? Q? 4;
The non-halogenated monocyclopentadienyl Group 4 metal compound (B) in the metallocene catalyst is a compound represented by the following general formula (3).

(3)
Wherein x is 0, 1, 2, 3 or 4, y is 0 or 1,
R is hydrogen, a hydrocarbon group having 1 to 20 carbon atoms, a silyl group, a halogen, or a multifunctional group thereof, and represents a substituent having 1 to 20 non-hydrogen atoms,
Y 'represents -O- or -NR * -, wherein R * represents hydrogen, a hydrocarbon group having 1 to 12 carbon atoms, a hydrocarbyloxy group having 1 to 8 carbon atoms, a silyl group, a halogenated alkyl group having 1 to 8 carbon atoms, A halogenated aryl group having from 1 to 20 carbon atoms, or a multifunctional group thereof)
Z represents SiR * ₂ , Si (OR *) R *, Si (OR *) ₂ , Si (NR *) R *, Si (NR *) ₂ or CR * ₂ , The same,
L each independently represent a hydrocarbon group of 1 to 30 carbon atoms,
M represents Ti. delete delete delete The catalyst according to claim 1, wherein the ratio (A / B) of the metallocene catalyst component (A) to the non-halogenated monocyclopentadienyl group-4 metal compound (B) in the metallocene catalyst is 0.01: 1 to 100: 1. The ethylene copolymer according to claim 1, wherein the metallocene catalyst (C) activating co-catalyst component is an aluminoxane selected from linear aluminoxane oligomers and cyclic aluminoxane oligomers. The method of claim 1, wherein the activated sensors the (C) in the catalyst tank to the metal catalyst component of the general formula _{AlR n X (3-n)} ( here, R is an alkyl group of carbon number 1 ~ 16, X is a halogen element, , 1? N? 3). The process according to claim 1, wherein the metallocene catalyst (C) activating co-catalyst component is an ionization activator selected from compounds represented by the following general formula (4), (5) Copolymer:
B (R ^a ) ₃ ..... (4)
[R ^b ] ⁺ [BR ^a ] ^- (5)
[R ^c -H] ⁺ [BR ^a ] ^- (6)
Wherein B is a boron atom, R ^a is phenyl or phenyloxy, the phenyl or phenyloxy is optionally substituted by a fluorine atom, an alkyl of 1 to 20 carbon atoms which is unsubstituted or substituted by a fluorine atom, be carbon atoms may further be substituted by 3-5 substituents selected from alkoxy of 1 to 20 and that, R ^b is a cycloalkyl radical having a carbon number of 5~7, (C1~C20) alkyl (C6~C20) aryl radical, or (C6~C30) aryl (C1~C20) alkyl radicals, [R ^c -H] ⁺ is an ammonium or phosphonium ion substituted with 1 to 3 (C1~C20) alkyl group. The method of claim 1, wherein the (D) carrier in the metallocene catalyst has micropores having an average particle size of 10 to 250 占 퐉, an average diameter of 50 to 500 占 and a micropore volume of 0.1 to 10 ml / g , And a surface area of 5 to 1000 m &lt; 2 &gt; / g. The ethylene copolymer according to claim 1, wherein the ethylene copolymer is produced by gas phase polymerization of a gas phase polymerization composition containing hydrogen, ethylene and a comonomer in the presence of a hydrocarbon as a reaction solvent using the metallocene catalyst Lt; / RTI &gt;

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