JP5593202B2 - Polyethylene for container lid - Google Patents

Description

  The present invention relates to a polyethylene resin for lids of containers that contain liquids such as soft drinks, and particularly in injection molding, high-speed moldability, high fluidity, rigidity, impact resistance, stress crack resistance, slipperiness, The present invention relates to a polyethylene resin excellent in low odor, food safety, openability, and closure performance.

Plastic containers are excellent in various physical properties, moldability, light weight, economy, etc., and are suitable for reusability in response to environmental issues. Recently, conventional containers made of metal or glass have been used. Overwhelming, it is widely used for daily necessities and industrial use. Among plastic containers, so-called PET bottles (polyethylene terephthalate containers) have been approved as containers for food and drink due to their excellent mechanical strength, transparency, high gas shielding properties, and non-polluting properties. There is a great demand for beverage containers. In particular, recently, small PET bottles have been heavily used by consumers as small containers for portable beverages, and the heat resistance and pressure resistance of PET bottles have improved, so that portable hot drinks for winter and long-term storage can be used. It is also widely used as a container for high-temperature sterilized beverages.
Along with polyester resins typified by PET bottles, polyethylene resins are also regarded as important container materials for beverages such as soft drinks, and demand is increasing.

Conventionally, in PET bottles as containers for soft drinks, polyolefin containers are often used as the container lids from the viewpoint of environmental conservation such as recycling and economy. These container lids are molded by continuous compression molding (CCM) for the purpose of high-speed molding.
The lid of containers such as soft drinks is an important product along with the container itself, in terms of the container's sealing and opening properties, food safety and durability, and other essential performances. From the viewpoint of various physical properties such as moldability and rigidity and heat resistance, the technical improvement of the lid member made of polyolefin, particularly polyethylene resin, has been continuously studied. Discloses a number of improvement proposals (see, for example, Patent Documents 1 to 7).

Among these, when looking at representative improvement proposals, Patent Document 1 defines the MFR (melt flow rate) and density of the polyethylene component in order to improve the pressure resistance and gas tightness of the cap for carbonated beverage containers. The polyethylene resin composition disclosed is disclosed, and the polyethylene resin composition disclosed in Patent Documents 2 and 3 produces various performances such as sealability and rigidity by compression molding and shortens the container lid molding cycle. In order to increase the efficiency, a high fluidity polyolefin resin is used for practical use.
Furthermore, a material having various performances such as heat resistance, rigidity, moldability, and stress crack resistance can be obtained by the polyethylene resin material disclosed in Patent Document 4 that presents a material with a specified number of short chain branches. A polyethylene-based resin material that can be realized and can withstand the internal pressure of carbonated beverages is beginning to be used as a carbonated beverage container lid.

In recent years, there is a demand for a high molding cycle that increases the molding speed for reasons of improving economy. In order to increase the molding speed, studies using polyethylene in a multistage polymerization with a wide molecular weight distribution are in progress. In addition, thinning of the container lid is being promoted for reasons of improving economy. However, in reducing the thickness of the container lid, the container lid is deformed by the internal pressure of the container so that the contents do not leak from the seal portion. Furthermore, higher rigidity is required. In recent years, a form of heating and selling containers containing beverages such as green tea with a heater has appeared, and in this warming sale, the shape is maintained even at high temperatures, and cracking does not occur due to tightening of the container lid Thus, further higher rigidity is demanded.
The polyethylene resin compositions disclosed in Patent Documents 5, 6, and 7 have a wide molecular weight distribution, various performance improvements such as moldability and stress crack resistance, and a low resin elongation even at high temperatures. A material in which the density of the resin material and the FRR (flow rate ratio) of MFR and MFR are defined, which is said to have improved plugging performance, is disclosed and put into practical use in compression molding.

  These polyethylenes can be improved by widening the molecular weight distribution by multistage polymerization or blending of a plurality of ethylene polymers in order to increase rigidity, improve moldability, and improve stress crack resistance. For polyethylene polymerized using a Ziegler catalyst, it is difficult to obtain a polymer having a narrow molecular weight distribution and further improved mechanical properties. In addition, in a polymer by single-stage polymerization with a narrow molecular weight distribution, the crystallization rate cannot be controlled effectively, and it is impossible to achieve a high molding cycle that increases the molding rate.

However, in recent years, with further technological progress, while maintaining high rigidity, impact resistance, stress crack resistance, slipperiness, low odor, food safety, openability, closure performance, and bridge breakability, There is a need for further high-speed molding of the container lid.
In view of such circumstances, while having the high rigidity, impact resistance, stress crack resistance, slipperiness, low odor, food safety, openability, and closure performance required for conventional container lids, Polyethylene material with high crystallization speed that can achieve high-speed molding and high cycle is required, and polyethylene with a relatively narrow molecular weight distribution has good moldability, excellent mechanical properties, and stress crack resistance. Therefore, there is a need for a polyethylene material that has rigidity and impact resistance and has a high crystallization speed that can achieve further high-speed molding and high cycle.

JP 58-103542 A JP 2000-159250 A JP 2000-248125 A JP 2002-60559 A Japanese Patent Laid-Open No. 2004-123955 JP 2004-244557 A JP 2004-300377 A

  In view of the above circumstances, the object of the present invention is excellent in high-speed moldability, high fluidity, rigidity, impact resistance, stress crack resistance, slipperiness, low odor, food safety, openability, and closure performance. It is another object of the present invention to provide a polyethylene material having a high crystallization speed that is further excellent in mechanical properties and can achieve high-speed molding and high cycle.

  As a result of intensive research to solve the above-mentioned problems, the present inventors have achieved high rigidity, impact resistance, stress crack resistance, slipperiness, low odor, food safety, It has been found that a polyethylene material can be obtained which is more excellent in mechanical properties and has a higher crystallization speed while having plugging and closing properties, and has completed the present invention.

That is, according to the first invention of the present invention, there is provided a metallocene complex having a cyclopentadienyl ring and a heterocyclic aromatic group, or a cyclopentadienyl ring and a fluorenyl ring, and containing Ti, Zr or Hf. It is polymerized using a metallocene catalyst comprising, and the following characteristics (1) to (5) and properties (i) - (vi) polyethylene container lids characterized by satisfying the requirements is provided.
Characteristic (1): Melt flow rate (MFR) at a temperature of 190 ° C. and a load of 2.16 kg is 1 to 10 g / 10 min.
Characteristic (2): Melt flow rate (HLMFR) at a temperature of 190 ° C. and a load of 21.6 Kg is 80 to 400 g / 10 minutes.
Characteristic (3): Melt flow rate ratio (HLMFR / MFR) is 20-80.
Characteristic (4): The density is 0.955 to 0.965 g / cm ³ .
Characteristic (5): Mw measured by HLMFR and GPC satisfies the relationship of log [HLMFR] ≦ −3.85 log [Mw / 10,000] +6.0.
Property (i): Flexural modulus is 850 MPa or more.
Characteristic (ii): Tensile yield strength is 25 MPa or more.
Characteristic (iii): Constant strain ESCR is 10 to 50 hours.
Characteristic (iv): The peak top time in isothermal crystallization at 121.5 ° C. measured by a differential scanning calorimeter (DSC) is 80 seconds or less.
Characteristic (v): The shrinkage ratio anisotropy (MD / TD) of the injection molded plate of 120 × 120 × 2 mm is 1.0 to 1.8.
Characteristic (vi): The hydrocarbon volatile content is 80 ppm or less.

According to the second invention of the present invention, there is provided a container lid polyethylene according to the first invention, wherein the metallocene catalyst contains a metallocene complex represented by the following general formula (II): Provided.
^{_{Q (C 5 H 4-c}} R 1 c) (C 5 H 4-d R 2 d) MXY ··· (II)
(In the formula, Q represents a binding group that bridges two conjugated five-membered ring ligands, M represents Ti, Zr, or Hf, and X and Y are each independently hydrogen, halogen, C1-C20 hydrocarbon group, C1-C20 oxygen-containing hydrocarbon group, C1-C20 nitrogen-containing hydrocarbon group, C1-C20 phosphorus-containing hydrocarbon group, or C1-C1 And R ¹ and R ² each independently represent a hydrocarbon group having 1 to 20 carbon atoms, a halogen group, a halogen-containing hydrocarbon group having 1 to 20 carbon atoms, an alkoxy group, An aryloxy group, an oxygen-containing hydrocarbon group, a sulfur-containing hydrocarbon group, a silicon-containing hydrocarbon group, a phosphorus-containing hydrocarbon group, a nitrogen-containing hydrocarbon group, or a boron-containing hydrocarbon group, and two adjacent R ^1, two ^{R 2} are carbon atoms bonded to each 4 10 Good .c and d also form a ring, each 0 ≦ c ≦ 4,0 ≦ d ≦ 4, an integer satisfying.)

According to the third invention of the present invention, in the second invention, at least one of the metallocene complexes represented by the general formula (II) is R ^{1 to} R ² in the compound. A polyethylene for container lids is provided, which is a crosslinked metallocene complex containing an aromatic group .

According to a fourth invention of the present invention, in the third invention, the heterocyclic aromatic group is selected from the group consisting of a furyl group, a benzofuryl group, a thienyl group, and a benzothienyl group. The container lid polyethylene is provided.

  The polyethylene for container lids of the present invention has excellent mechanical properties while having high rigidity, impact resistance, stress crack resistance, slipperiness, low odor, food safety, openability, and closure performance. Further, it is a polyethylene material having a higher crystallization speed. Moreover, since there is little shrinkage | contraction rate anisotropy, it is suitable for the lid | cover of the container for accommodating the liquid of the drink with a PET bottle.

Hereinafter, the present invention will be described in detail for each item.
1. Characteristics of polyethylene for container lid The polyethylene for container lid of the present invention is characterized by satisfying the requirements of the following characteristics (1) to (5).

Characteristic (1): Melt flow rate (MFR) at a temperature of 190 ° C. and a load of 2.16 kg is 1 to 10 g / 10 min.
Characteristic (2): Melt flow rate (HLMFR) at a temperature of 190 ° C. and a load of 21.6 Kg is 80 to 400 g / 10 minutes.
Characteristic (3): Melt flow rate ratio (HLMFR / MFR) is 20-80.
Characteristic (4): The density is 0.955 to 0.965 g / cm ³ .
Characteristic (5): Mw measured by HLMFR and GPC satisfies the relationship of log [HLMFR] ≦ −3.85 log [Mw / 10,000] +6.0.

The polyethylene of the present invention has a melt flow rate (MFR) of 1 to 10 g / 10 minutes at a temperature of 190 ° C. and a load of 2.16 kg, preferably 2 to 9 g / 10 minutes, more preferably 3 to 7 g / 10 minutes. is there. If the MFR is less than 1 g / 10 min, the fluidity is lowered and the moldability is inferior. On the other hand, if the MFR exceeds 10 g / 10 min, the stress crack resistance cannot be achieved, and the crystallization rate is reduced. The isothermal crystallization time at 121.5 ° C., which can be measured at over 80 seconds, results in a reduction in the molding cycle. Here, MFR is a value measured according to JIS K6922-2: 1997.
MFR can be adjusted by ethylene polymerization temperature, use of a chain transfer agent, etc., and a desired thing can be obtained. That is, by increasing the polymerization temperature of ethylene and α-olefin, the molecular weight can be decreased, and as a result, the MFR can be increased. On the other hand, by decreasing the polymerization temperature, the molecular weight can be increased, and as a result, the MFR can be decreased. Can do. Further, by increasing the amount of hydrogen coexisting in the copolymerization reaction of ethylene and α-olefin (amount of chain transfer agent), the molecular weight can be lowered, resulting in an increase in MFR, while the amount of coexisting hydrogen ( The molecular weight can be increased by reducing the chain transfer agent amount), and as a result, the MFR can be reduced.

The polyethylene of the present invention has a melt flow rate (HLMFR) at a temperature of 190 ° C. and a load of 21.6 Kg of 80 to 400 g / 10 minutes, preferably 120 to 300 g / 10 minutes. When the HLMFR is less than 80 g / 10 minutes, the high-speed moldability is inferior, whereas when it exceeds 400 g / 10 minutes, the stress crack resistance of the container lid is inferior. Here, HLMFR is a value measured according to JIS K6922-2: 1997.
HLMFR can also be adjusted by the ethylene polymerization temperature, the use of a chain transfer agent, and the like, and a desired product can be obtained while balancing with other physical properties. That is, by increasing the polymerization temperature of ethylene and α-olefin, the molecular weight can be decreased, and as a result, the HLMFR can be increased. On the other hand, by decreasing the polymerization temperature, the molecular weight can be increased, and as a result, the HLMFR can be decreased. Can do. Further, by increasing the amount of hydrogen coexisting in the copolymerization reaction of ethylene and α-olefin (amount of chain transfer agent), the molecular weight can be lowered, and as a result, HLMFR can be increased, while the amount of hydrogen coexisting ( The molecular weight can be increased by reducing the amount of chain transfer agent), and as a result, HLMFR can be reduced.

The polyethylene of the present invention has an HLMFR / MFR of 20 to 80, preferably 20 to 60, and more preferably 20 to 40. When HLMFR / MFR is less than 20, high-speed moldability is poor, while when it exceeds 80, shrinkage ratio anisotropy increases.
HLMFR / MFR can be increased or decreased by adjusting the molecular weight distribution. This HLMFR / MFR is correlated with monodispersity of the molecular weight (weight average molecular weight Mw / number average molecular weight Mn) by gel permeation chromatography, and 80 of HLMFR / MFR is about 16 of the monodispersity Mw / Mn. And HLMFR / MFR = 20 corresponds to about 2 of monodisperse Mw / Mn. HLMFR / MFR and Mw / Mn can be adjusted by the type of catalyst, the type of cocatalyst, the polymerization temperature, the residence time in the polymerization reactor, the number of polymerization reactors, etc. It can be adjusted by the speed, etc., and can be preferably increased or decreased by adjusting the mixing ratio of the high molecular weight component and the low molecular weight component, and can be increased by increasing the difference in average molecular weight of each component.

The polyethylene of the present invention has a density of 0.955 to 0.965 g / cm ³ , preferably 0.955 to 0.963 g / cm ³ , and more preferably 0.958 to 0.961 g / cm ³ . When the density is less than 0.955 g / cm ³ , the rigidity of the container lid is inferior and easily deforms at a high temperature, and the container lid is deformed due to the influence of the internal pressure of the container and causes leakage. On the other hand, when the density exceeds 0.965 g / cm ³ , the stress crack resistance of the container lid is inferior. Here, the density is a value measured according to JIS K6922-1, 2: 1997.
A desired density can be obtained by changing the density depending on the kind and amount of the comonomer copolymerized with ethylene.

In the polyethylene of the present invention, the melt flow rate (HLMFR) at a load of 21.6 kg and Mw measured by GPC satisfy the following relational expression (1).
Formula (1): log [HLMFR] ≦ −3.85 log [Mw / 10,000] +6.0

  By using polyethylene that satisfies this relational expression, the crystallization rate can be increased very effectively, and the same effect as when a so-called crystal nucleating agent is added can be obtained, and the crystallization time can be shortened. High-speed molding and high cycle as a polyethylene resin for lids can be achieved. In addition, by using polyethylene that satisfies this relational expression, it is possible to further improve the stress crack resistance as compared with conventional materials.

In conventional ethylene-based polymers, methods such as adding a substance that acts as a crystal nucleating agent have been tried to increase the crystallization speed. As a result of studying ethylene polymers that sufficiently improve both physical properties such as mechanical strength, crystallization while maintaining excellent physical properties such as mechanical strength by using the polyethylene of the present invention (ethylene polymer) The speed can be sufficiently improved, and the molding speed can be improved.
The crystallization rate can be sufficiently improved by an ethylene polymer satisfying the relational expression (1), preferably an expression (2), more preferably an ethylene polymer satisfying the expression (3). The remarkable effect in this invention can be exhibited.
Formula (2): log [HLMFR] ≦ −3.85 log [Mw / 10,000] +5.8
Formula (3): log [HLMFR] ≦ −3.85 log [Mw / 10,000] +5.6

Here, the technical meaning of the above formula (1) indicates that the fluidity is low in proportion to the weight average molecular weight, that is, the HLMFR is small. This indicates that the ethylene polymer is a long chain. It shows that the polymer is an ethylene polymer having a branched structure and a long-chain branched structure exhibiting a specific HLMFR with respect to a predetermined Mw.
In the technical field to which the present invention pertains, various methods are known for measuring an ethylene polymer having a long-chain branched structure. For example, polymers that show rise in viscosity in the measurement of elongational viscosity are also long-chain polymers. Included in ethylene polymers having a branched structure. Of the ethylene-based polymers having a long-chain branched structure, those satisfying the formula of the present invention are suitable as those having a specific long-chain branched structure.
Specific examples of the long-chain branched structure that controls the molding speed include, but are not limited to, a star-shaped branched polymer and a comb-shaped branched polymer, and ethylene that satisfies the above specific formula is not limited thereto. If it is a system polymer, the effect of improving the crystallization speed can be exhibited. Furthermore, if the ethylene-based polymer does not satisfy the above relational expression, it does not work effectively as a long-chain branched polymer, the crystallization speed cannot be increased, and the molding speed is difficult to improve.

Examples of the ethylene-based polymer having a long-chain branch structure according to the present invention include a polymer having about one long-chain branch per 10,000 carbon chain, which is, for example, ¹³ C-NMR measurement. Can be confirmed. The ethylene-based polymer having a long chain branched structure can be produced by polymerization using a chromium catalyst such as a Philips catalyst or a metallocene catalyst as a single site catalyst as a polymerization catalyst.
Moreover, as an ethylene polymer having a long chain branched structure, polyethylene having a terminal vinyl group (macromonomer) is generated by chain transfer to ethylene, and a long chain branched structure is obtained through copolymerization of the macromonomer and ethylene. The polymer which has can be obtained.
Among metallocene catalysts, a catalyst having a metallocene complex having a specific structure is preferable, and a metallocene catalyst having a cyclopentadienyl ring and a heterocyclic aromatic group, or a metallocene catalyst having a cyclopentadienyl ring and a fluorenyl ring is particularly preferable. .

2. Method for Producing Polyethylene for Container Lids The polyethylene of the present invention is preferably polymerized with a metallocene catalyst, more preferably a metallocene catalyst containing Ti, Zr, or Hf. Examples of the metallocene catalyst include a combination of a complex called a metallocene catalyst in which a ligand having a cyclopentadiene skeleton is coordinated to a transition metal and a promoter. Specific examples of the metallocene catalyst include a complex catalyst in which a ligand having a cyclopentadiene skeleton such as methylcyclopentadiene, dimethylcyclopentadiene, and indene is coordinated to a transition metal containing Ti, Zr, Hf, and the like. Examples of the catalyst include a combination of organic metal compounds of Group 1 to Group 3 elements such as aluminoxane, and a supported type in which these complex catalysts are supported on a carrier such as silica.

The metallocene catalyst used in the present invention contains the following component (A) and component (B), and is a catalyst combined with component (C) as necessary.
Component (A): Metallocene complex Component (B): Compound that reacts with component (A) to form a cationic metallocene compound Component (C): Fine particle carrier

(1) Component (A)
As the component (A), a metallocene compound of a Group 4 transition metal is used. Specifically, compounds represented by the following general formulas (I) to (VI) are used.
^{_{(C 5 H 5-a R}} 1 a) (C 5 H 5-b R 2 b) MXY ··· (I)
^{_{Q (C 5 H 4-c}} R 1 c) (C 5 H 4-d R 2 d) MXY ··· (II)
^{_{Q '(C 5 H 4-}} e R 3 e) ZMXY ··· (III)
^{_{(C 5 H 5-f R}} 3 f) ZMXY ··· (IV)
^{_{(C 5 H 5-f R}} 3 f) MXYW ··· (V)
Q ″ (C ₅ H _5-g R ⁴ _g ) (C ₅ H _5-h R ⁵ _h ) MXY (VI)

Here, Q represents a binding group that bridges two conjugated five-membered ring ligands, Q ′ represents a binding group that bridges the conjugated five-membered ring ligand and the Z group, and Q ″ represents , R ⁴ and R ⁵ represent a bonding group, M represents Ti, Zr, or Hf, X, Y, and W each independently represent hydrogen, halogen, or a hydrocarbon having 1 to 20 carbon atoms. A group, an oxygen-containing hydrocarbon group having 1 to 20 carbon atoms, a nitrogen-containing hydrocarbon group having 1 to 20 carbon atoms, a phosphorus-containing hydrocarbon group having 1 to 20 carbon atoms, or a silicon-containing hydrocarbon group having 1 to 20 carbon atoms. Z represents a ligand containing oxygen and sulfur, a silicon-containing hydrocarbon group having 1 to 40 carbon atoms, a nitrogen-containing hydrocarbon group having 1 to 40 carbon atoms, or a phosphorus-containing hydrocarbon group having 1 to 40 carbon atoms. Show.

R ^{1 to} R ⁵ are each independently a hydrocarbon group having 1 to 20 carbon atoms, a halogen group, a halogen-containing hydrocarbon group having 1 to 20 carbon atoms, an alkoxy group, an aryloxy group, an oxygen-containing hydrocarbon group, A sulfur-containing hydrocarbon group, a silicon-containing hydrocarbon group, a phosphorus-containing hydrocarbon group, a nitrogen-containing hydrocarbon group or a boron-containing hydrocarbon group is shown. Two adjacent R ¹ , 2 R ² , 2 R ³ , 2 R ⁴ , or 2 R ⁵ are bonded to each other to form a ring having 4 to 10 carbon atoms. You may do it. A, b, c, d, e, f, and h are 0 ≦ a ≦ 5, 0 ≦ b ≦ 5, 0 ≦ c ≦ 4, 0 ≦ d ≦ 4, 0 ≦ e ≦ 4, and 0 ≦, respectively. It is an integer that satisfies f ≦ 5, 0 ≦ g ≦ 5, and 0 ≦ h ≦ 5.

A bonding group Q that bridges between two conjugated five-membered ring ligands, a bonding group Q ′ that bridges a conjugated five-membered ring ligand and a Z group, and bridges R ⁴ and R ⁵ Specific examples of Q ″ include the following.
That is, an alkylene group such as a methylene group, an ethylene group, an ethylidene group, a propylidene group, an isopropylidene group, a phenylmethylidene group, an alkylidene group such as a diphenylmethylidene group, a dimethylsilylene group, a diethylsilylene group, a dipropylsilylene group , Silicon-containing crosslinking groups such as diphenylsilylene group, methylethylsilylene group, methylphenylsilylene group, methyl-t-butylsilylene group, disilylene group, tetramethyldisylylene group, germanium-containing crosslinking group, alkylphosphine, amine, etc. It is. Among these, an alkylene group, an alkylidene group, a silicon-containing crosslinking group, and a germanium-containing crosslinking group are particularly preferably used.

Specific Zr complexes represented by the above general formulas (I), (II), (III), (IV), (V) and (VI) are exemplified below, but Zr is replaced with Hf or Ti. The same compounds can be used as well.
In addition, the component (A) represented by the general formulas (I), (II), (III), (IV), (V) and (VI) may be a compound represented by the same general formula or a different general formula. It can be used as a mixture of two or more of the compounds shown.

Compounds of general formula (I):
Biscyclopentadienylzirconium dichloride, bis (2-methylindenyl) zirconium dichloride, bis (2-methyl-4,5benzoindenyl) zirconium dichloride, bisfluorenylzirconium dichloride, bis (4H-azurenyl) zirconium dichloride Bis (2-methyl-4H-azurenyl) cyclopentadienylzirconium dichloride, bis (2-methyl-4-phenyl-4H-azurenyl) zirconium dichloride, bis (2-methyl-4- (4-chlorophenyl) -4H -Azulenyl) zirconium dichloride.
Bis (2-furylcyclopentadienyl) zirconium dichloride, bis (2-furylindenyl) zirconium dichloride, bis (2-furyl-4,5-benzoindenyl) zirconium dichloride.

Compound of general formula (II):
Dimethylsilylenebis (1,1′-cyclopentadienyl) zirconium dichloride, dimethylsilylenebis [1,1 ′-(2-methylindenyl)] zirconium dichloride, dimethylsilylenebis [1,1 ′-(2-methyl) Indenyl)] zirconium dichloride, ethylenebis [1,1 ′-(2-methyl-4,5benzoindenyl)] zirconium dichloride, dimethylsilylenebis [1,1 ′-(2-methyl-4-hydroazurenyl)] Zirconium dichloride, dimethylsilylenebis [1,1 ′-(2-methyl-4-phenyl-4-hydroazulenyl)] zirconium dichloride, dimethylsilylenebis {1,1 ′-[2-methyl-4- (4-chlorophenyl) -4-hydroazulenyl]} zirconium dichloride, dimethylsilylene bis [ 1,1 ′-(2-Ethyl-4-phenyl-4-hydroazurenyl)] zirconium dichloride, ethylenebis [1,1 ′-(2-methyl-4-hydroazurenyl)] zirconium dichloride.
Dimethylsilylenebis [1,1 ′-(2-furylcyclopentadienyl)] zirconium dichloride, dimethylsilylenebis {1,1 ′-[2- (2-furyl) -4,5-dimethyl-cyclopentadienyl] ]} Zirconium dichloride, dimethylsilylenebis {1,1 ′-{2- [2- (5-trimethylsilyl) furyl] -4,5-dimethyl-cyclopentadienyl}} zirconium dichloride, dimethylsilylenebis {1,1 '-[2- (2-furyl) indenyl]} zirconium dichloride, dimethylsilylenebis {1,1'-[2- (2-furyl) -4-phenyl-indenyl]} zirconium dichloride, isopropylidene (cyclopentadiene) Enyl) (9-fluorenyl) zirconium dichloride, isopropylidene (cyclopentadienyl) ) [9- (2,7-t-butyl) fluorenyl] zirconium dichloride, diphenylmethylene (cyclopentadienyl) (9-fluorenyl) zirconium dichloride, diphenylmethylene (cyclopentadienyl) [9- (2,7- t-butyl) fluorenyl] zirconium dichloride, dimethylsilylene (cyclopentadienyl) (9-fluorenyl) zirconium dichloride, diphenylsilylene (cyclopentadienyl) [9- (2,7-t-butyl) fluorenyl] zirconium dichloride.

Compound of general formula (III):
(Tertiary butylamide) (tetramethyl-η ⁵ -cyclopentadienyl) -1,2-ethanediylzirconium dichloride, (methylamide)-(tetramethyl-η ⁵ -cyclopentadienyl) -1,2-ethanediyl -Zirconium dichloride, (ethylamide) (tetramethyl-η ⁵ -cyclopentadienyl) -methylenezirconium dichloride, (tertiary butylamide) dimethyl- (tetramethyl-η ⁵ -cyclopentadienyl) silane zirconium dichloride, tertiary butylamido) dimethyl (tetramethyl-eta ⁵ - cyclopentadienyl) silane zirconium dibenzyl, (benzylamide) dimethyl (tetramethyl-eta ⁵ - cyclopentadienyl) silane zirconium dichloride, (phenylalanine phosphine id) dimethacrylate Le (tetramethyl- eta ⁵ - cyclopentadienyl) silane zirconium dibenzyl.

Compound of general formula (IV):
(Cyclopentadienyl) (phenoxy) zirconium dichloride, (2,3-dimethylcyclopentadienyl) (phenoxy) zirconium dichloride, (pentamethylcyclopentadienyl) (phenoxy) zirconium dichloride, (cyclopentadienyl) ( 2,6-di-t-butylphenoxy) zirconium dichloride, (pentamethylcyclopentadienyl) (2,6-di-i-propylphenoxy) zirconium dichloride.

Compound of general formula (V):
(Cyclopentadienyl) zirconium trichloride, (2,3-dimethylcyclopentadienyl) zirconium trichloride, (pentamethylcyclopentadienyl) zirconium trichloride, (cyclopentadienyl) zirconium triisopropoxide, ( Pentamethylcyclopentadienyl) zirconium triisopropoxide.

Compound of general formula (VI):
Ethylene bis (7,7′-indenyl) zirconium dichloride, dimethylsilylene bis {7,7 ′-(1-methyl-3-phenylindenyl)} zirconium dichloride, dimethylsilylene bis {7,7 ′-[1-methyl -4- (1-naphthyl) indenyl]} zirconium dichloride, dimethylsilylenebis [7,7 '-(1-ethyl-3-phenylindenyl)] zirconium dichloride, dimethylsilylenebis {7,7'-[1- Isopropyl-3- (4-chlorophenyl) indenyl]} zirconium dichloride.

In addition, the compound which replaced the silylene group of the compound of these specific examples with the germylene group is illustrated as a suitable compound.
Among the transition metal compound components (A) described above, preferred metallocene complexes for producing ethylene polymers are preferably metallocene complexes represented by general formula (I) or general formula (II), Furthermore, a metallocene complex represented by the general formula (II) is preferable from the viewpoint that a high molecular weight polymer can be produced and copolymerization is excellent in copolymerization of ethylene and other α-olefin. The ability to produce a high molecular weight product has the advantage that polymers with various molecular weights can be designed by adjusting the molecular weight of various polymers as described below.
Furthermore, one method for satisfying the relationship of the formula (1) in which the melt flow rate (HLMFR) at a load of 21.6 kg and Mw measurable by GPC satisfies the relationship of the formula (1) is to introduce long chain branching into the ethylene polymer. However, from the viewpoint that a polyethylene having a high molecular weight and a long chain branch can be produced, among the metallocene complexes represented by the general formula (II), the following two compound groups are preferable.

As a preferred embodiment, the first compound group is a bridged metallocene complex containing at least one heterocyclic aromatic group in the compound as R ^{1 to} R ² . Preferred heterocyclic aromatic groups include the group consisting of a furyl group, a benzofuryl group, a thienyl group, and a benzothienyl group. These substituents may further have a substituent such as a silicon-containing group. Of the substituents selected from the group consisting of a furyl group, a benzofuryl group, a thienyl group, and a benzothienyl group, a furyl group and a benzofuryl group are more preferable. Further, these substituents are preferably introduced at the 2-position of the substituted cyclopentadienyl group or the substituted indenyl group, and at least one other substituted cyclopentadienyl group having no condensed ring structure is introduced. It is particularly preferred that the compound has.

  The second group of compounds is a bridged metallocene complex in which a substituted cyclopentadienyl group and a substituted fluorenyl group are combined.

  These metallocene complexes are preferably used as supported catalysts as described later. In the first group of compounds, the furyl group interacts with the so-called heteroatom contained in the thienyl group and the solid acid on the support, causing non-uniformity in the active site structure and easily generating long chain branching. I think. Also in the second compound group, it is thought that the use of a supported catalyst changed the space around the active site, so that long chain branching was easily generated.

(2) Component (B)
In the method for producing an ethylene-based polymer of the present invention, as an essential component of an olefin polymerization catalyst, in addition to the above component (A), the metallocene compound of component (A) (component (A), hereinafter simply referred to as A) A compound that forms a cationic metallocene compound (component (B), hereinafter may be simply referred to as B), and a fine particle carrier (component (C), hereinafter simply referred to as C). It may be noted that there is a feature.

As one of the compounds (B) that react with the metallocene compound (A) to form a cationic metallocene compound, an organoaluminum oxy compound can be mentioned.
The organoaluminum oxy compound has Al—O—Al bonds in the molecule, and the number of bonds is usually in the range of 1 to 100, preferably 1 to 50. Such an organoaluminum oxy compound is usually a product obtained by reacting an organoaluminum compound with water.
The reaction between organoaluminum and water is usually carried out in an inert hydrocarbon (solvent). As the inert hydrocarbon, aliphatic hydrocarbons such as pentane, hexane, heptane, cyclohexane, methylcyclohexane, benzene, toluene, xylene, alicyclic hydrocarbons and aromatic hydrocarbons can be used. Preference is given to using aromatic hydrocarbons.

As the organoaluminum compound used for the preparation of the organoaluminum oxy compound, any of the compounds represented by the following general formula (3) can be used, but trialkylaluminum is preferably used.
R ⁵ _t AlX ³ _3-t Formula (3)
(In the formula, R ⁵ represents a hydrocarbon group such as an alkyl group, alkenyl group, aryl group or aralkyl group having 1 to 18 carbon atoms, preferably 1 to 12 carbon atoms, and X ³ represents a hydrogen atom or a halogen atom. , T represents an integer of 1 ≦ t ≦ 3.)

The alkyl group of the trialkylaluminum may be any of methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, pentyl group, hexyl group, octyl group, decyl group, dodecyl group, etc. It is particularly preferred that
Two or more of the above organoaluminum compounds can be mixed and used.

The reaction ratio (water / Al molar ratio) between water and the organoaluminum compound is preferably 0.25 / 1 to 1.2 / 1, particularly preferably 0.5 / 1 to 1/1, and the reaction temperature is Usually, it is -70-100 degreeC, Preferably it exists in the range of -20-20 degreeC. The reaction time is usually selected in the range of 5 minutes to 24 hours, preferably 10 minutes to 5 hours. As water required for the reaction, not only mere water but also crystal water contained in copper sulfate hydrate, aluminum sulfate hydrate and the like and components capable of generating water in the reaction system can be used.
Of the organoaluminum oxy compounds described above, those obtained by reacting alkylaluminum with water are usually called aluminoxanes, particularly methylaluminoxane (including those substantially consisting of methylaluminoxane (MAO)). Is suitable as an organoaluminum oxy compound.
Of course, as the organoaluminum oxy compound, two or more of the above organoaluminum oxy compounds may be used in combination, and a solution obtained by dispersing or dispersing the organoaluminum oxy compound in the above-described inert hydrocarbon solvent. You may use.

Moreover, a borane compound and a borate compound are mentioned as another specific example of the compound (B) which reacts with a metallocene compound (A) and forms a cationic metallocene compound.
More specifically, the borane compound is represented by triphenylborane, tri (o-tolyl) borane, tri (p-tolyl) borane, tri (m-tolyl) borane, tri (o-fluorophenyl) borane, tris ( p-fluorophenyl) borane, tris (m-fluorophenyl) borane, tris (2,5-difluorophenyl) borane, tris (3,5-difluorophenyl) borane, tris (4-trifluoromethylphenyl) borane, tris (3,5-ditrifluoromethylphenyl) borane, tris (2,6-ditrifluoromethylphenyl) borane, tris (pentafluorophenyl) borane, tris (perfluoronaphthyl) borane, tris (perfluorobiphenyl), tris ( Perfluoroanthryl) borane, tris (perfluorobi) Fuchiru) such as borane and the like.

  Among these, tris (3,5-ditrifluoromethylphenyl) borane, tris (2,6-ditrifluoromethylphenyl) borane, tris (pentafluorophenyl) borane, tris (perfluoronaphthyl) borane, tris (perfluoro) Biphenyl) borane, tris (perfluoroanthryl) borane, and tris (perfluorobinaphthyl) borane are more preferred, and tris (2,6-ditrifluoromethylphenyl) borane, tris (pentafluorophenyl) borane, tris ( Perfluoronaphthyl) borane and tris (perfluorobiphenyl) borane are exemplified as preferred compounds.

When the borate compound is specifically represented, the first example is a compound represented by the following general formula (4).
^{[L 1 -H] + [BR} 6 R 7 X 4 X 5] - ··· Equation (4)

In Formula (4), L ¹ is a neutral Lewis base, H is a hydrogen atom, and [L ¹ -H] is a Bronsted acid such as ammonium, anilinium, phosphonium or the like.
Examples of ammonium include trialkylammonium such as trimethylammonium, triethylammonium, tripropylammonium, tributylammonium, and tri (n-butyl) ammonium, and dialkylammonium such as di (n-propyl) ammonium and dicyclohexylammonium.

Examples of anilinium include N, N-dialkylanilinium such as N, N-dimethylanilinium, N, N-diethylanilinium, N, N-2,4,6-pentamethylanilinium.
Furthermore, examples of the phosphonium include triarylphosphonium, tributylphosphonium, triarylphosphonium such as tri (methylphenyl) phosphonium, tri (dimethylphenyl) phosphonium, and trialkylphosphonium.

In formula (4), R ⁶ and R ⁷ are the same or different aromatic or substituted aromatic hydrocarbon groups containing 6 to 20, preferably 6 to 16 carbon atoms, and are connected to each other by a bridging group. As the substituent of the substituted aromatic hydrocarbon group, an alkyl group typified by a methyl group, an ethyl group, a propyl group, an isopropyl group or the like, or a halogen such as fluorine, chlorine, bromine or iodine is preferable.
Further, X ⁴ and X ⁵ are a hydride group, a halide group, a hydrocarbon group containing 1 to 20 carbon atoms, a substituted carbon atom containing 1 to 20 carbon atoms in which one or more hydrogen atoms are replaced by halogen atoms. It is a hydrogen group.

  Specific examples of the compound represented by the general formula (4) include tributylammonium tetra (pentafluorophenyl) borate, tributylammonium tetra (2,6-ditrifluoromethylphenyl) borate, tributylammonium tetra (3,5- Ditrifluoromethylphenyl) borate, tributylammonium tetra (2,6-difluorophenyl) borate, tributylammonium tetra (perfluoronaphthyl) borate, dimethylanilinium tetra (pentafluorophenyl) borate, dimethylanilinium tetra (2,6- Ditrifluoromethylphenyl) borate, dimethylanilinium tetra (3,5-ditrifluoromethylphenyl) borate, dimethylanilinium tetra (2,6-difluoropheny) ) Borate, dimethylanilinium tetra (perfluoronaphthyl) borate, triphenylphosphonium tetra (pentafluorophenyl) borate, triphenylphosphonium tetra (2,6-ditrifluoromethylphenyl) borate, triphenylphosphonium tetra (3,5- Ditrifluoromethylphenyl) borate, triphenylphosphonium tetra (2,6-difluorophenyl) borate, triphenylphosphonium tetra (perfluoronaphthyl) borate, trimethylammonium tetra (2,6-ditrifluoromethylphenyl) borate, triethylammonium tetra (Pentafluorophenyl) borate, triethylammonium tetra (2,6-ditrifluoromethylphenyl) borate, triethyla Monium tetra (perfluoronaphthyl) borate, tripropylammonium tetra (pentafluorophenyl) borate, tripropylammonium tetra (2,6-ditrifluoromethylphenyl) borate, tripropylammonium tetra (perfluoronaphthyl) borate, di (1 -Propyl) ammonium tetra (pentafluorophenyl) borate, dicyclohexylammonium tetraphenylborate and the like.

  Among these, tributylammonium tetra (pentafluorophenyl) borate, tributylammonium tetra (2,6-ditrifluoromethylphenyl) borate, tributylammonium tetra (3,5-ditrifluoromethylphenyl) borate, tributylammonium tetra (perfluoro) Naphthyl) borate, dimethylaniliniumtetra (pentafluorophenyl) borate, dimethylaniliniumtetra (2,6-ditrifluoromethylphenyl) borate, dimethylaniliniumtetra (3,5-ditrifluoromethylphenyl) borate, dimethylanilinium Tetra (perfluoronaphthyl) borate is preferred.

Moreover, the 2nd example of a borate compound is represented by following General formula (5).
^{[L 2] + [BR 6} R 7 X 4 X 5] - ··· Equation (5)

In the formula (5), L ² is carbocation, methyl cation, ethyl cation, propyl cation, isopropyl cation, butyl cation, isobutyl cation, tert-butyl cation, pentyl cation, tropinium cation, benzyl cation, trityl cation, sodium. A cation, a proton, etc. are mentioned. R ⁶ , R ⁷ , X ⁴ and X ⁵ are the same as defined in the general formula (4).

Specific examples of the compound include trityl tetraphenyl borate, trityl tetra (o-tolyl) borate, trityl tetra (p-tolyl) borate, trityl tetra (m-tolyl) borate, trityl tetra (o-fluorophenyl) borate, Trityltetra (p-fluorophenyl) borate, trityltetra (m-fluorophenyl) borate, trityltetra (3,5-difluorophenyl) borate, trityltetra (pentafluorophenyl) borate, trityltetra (2,6-ditrifluoro) Methylphenyl) borate, trityltetra (3,5-ditrifluoromethylphenyl) borate, trityltetra (perfluoronaphthyl) borate, tropiniumtetraphenylborate, tropiniumtetra (o-tolyl) Rate, tropinium tetra (p-tolyl) borate, tropinium tetra (m-tolyl) borate, tropinium tetra (o-fluorophenyl) borate, tropinium tetra (p-fluorophenyl) borate, tropinium tetra (m- Fluorophenyl) borate, tropinium tetra (3,5-difluorophenyl) borate, tropinium tetra (pentafluorophenyl) borate, tropinium tetra (2,6-ditrifluoromethylphenyl) borate, tropinium tetra (3,5 - ditrifluoromethylphenyl) borate, tropicity tetra (perfluoro-naphthyl) _{borate, NaBPh 4, NaB (o-} CH 3 -Ph) 4, NaB (p-CH 3 -Ph) 4, NaB (m-CH 3 - Ph) ₄ , Na _{B (o-F-Ph)} 4, NaB (p-F-Ph) 4, NaB (m-F-Ph) 4, NaB (3,5-F 2 -Ph) 4, NaB (C 6 F 5) ₄ , NaB (2,6- (CF ₃ ) ₂ -Ph) ₄ , NaB (3,5- (CF ₃ ) ₂ -Ph) ₄ , NaB (C ₁₀ F ₇ ) ₄ , H ⁺ BPh ₄ · 2 diethyl _{^{ethers, H + B (3,5-F}} 2 -Ph) 4 · 2 diethyl ^{_{ether, H + B (C 6 F}} 5) 4 - · 2 diethyl _{^{ether, H + B (2,6- (CF}} 3) 2 _{-Ph) 4} · 2 diethyl _{^{ether, H + B (3,5- (CF}} 3) 2 -Ph) 4 · 2 diethyl ^ether, can be exemplified _{H + B (C 10 H 7} ) 4 · 2 diethyl ether it can.

Among these, trityltetra (pentafluorophenyl) borate, trityltetra (2,6-ditrifluoromethylphenyl) borate, trityltetra (3,5-ditrifluoromethylphenyl) borate, trityltetra (perfluoronaphthyl) borate, Tropinium tetra (pentafluorophenyl) borate, tropinium tetra (2,6-ditrifluoromethylphenyl) borate, tropinium tetra (3,5-ditrifluoromethylphenyl) borate, tropinium tetra (perfluoronaphthyl) borate, _{NaB (C 6 F 5) 4} , NaB (2,6- (CF 3) 2 -Ph) 4, NaB (3,5- (CF 3) 2 -Ph) 4, NaB (C 10 F 7) 4, ^{_{H + B (C 6 F 5}} ) 4 - · 2 diethyl _{^{Ether, H + B (2,6- (CF}} 3) 2 -Ph) 4 · 2 diethyl _{^{ether, H + B (3,5- (CF}} 3) 2 -Ph) 4 · 2 diethyl ^{ether, H} + B ( C ₁₀ H _{7) 4} · 2 diethyl ether.

More preferably, among these, trityltetra (pentafluorophenyl) borate, trityltetra (2,6-ditrifluoromethylphenyl) borate, tropiniumtetra (pentafluorophenyl) borate, tropiniumtetra (2,6-ditrifluoro) methylphenyl) _{borate, NaB (C 6 F 5)} 4, NaB (2,6- (CF 3) 2 -Ph) 4, H + B (C 6 F 5) 4 - · 2 diethyl ^{ether, H} + B ( _{2,6- (CF 3) 2 -Ph)} 4 · 2 diethyl _{^{ether, H + B (3,5- (CF}} 3) 2 -Ph) 4 · 2 diethyl ^{_{ether, H + B (C 10 H}} 7) 4 -2 diethyl ether is mentioned.

(3) Component (C)
Examples of the fine particle carrier as the component (C) include an inorganic carrier, a particulate polymer carrier, and a mixture thereof. As the inorganic carrier, a metal, a metal oxide, a metal chloride, a metal carbonate, a carbonaceous material, or a mixture thereof can be used.
Suitable metals that can be used for the inorganic carrier include, for example, iron, aluminum, nickel, and the like.

Further, as the metal oxide, either alone oxide or composite oxide of the Periodic Table 1-14 Group elements include, for _{example, SiO 2, Al 2 O 3} , MgO, CaO, B 2 O 3, TiO 2, _{ZrO 2, Fe 2 O 3,} Al 2 O 3 · MgO, Al 2 O 3 · CaO, Al 2 O 3 · SiO 2, Al 2 O 3 · MgO · CaO, Al 2 O 3 · MgO · SiO 2, Al Examples include various natural or synthetic single oxides or composite oxides such as ₂ O ₃ .CuO, Al ₂ O ₃ .Fe ₂ O ₃ , Al ₂ O ₃ .NiO, and SiO ₂ .MgO.
Here, the above formula is not a molecular formula but represents only the composition, and the structure and component ratio of the composite oxide used in the present invention are not particularly limited.
In addition, the metal oxide used in the present invention may absorb a small amount of moisture or may contain a small amount of impurities.

As the metal chloride, for example, an alkali metal or alkaline earth metal chloride is preferable, and specifically, MgCl ₂ , CaCl _{2 and the} like are particularly preferable.
As the metal carbonate, carbonates of alkali metals and alkaline earth metals are preferable, and specific examples include magnesium carbonate, calcium carbonate, barium carbonate and the like.
Examples of the carbonaceous material include carbon black and activated carbon.
Any of the above inorganic carriers can be suitably used in the present invention, but the use of metal oxides, silica, alumina and the like is particularly preferable.

These inorganic carriers are usually calcined in air or an inert gas such as nitrogen or argon at 200 to 800 ° C., preferably 400 to 600 ° C., and the amount of surface hydroxyl groups is 0.8 to 1.5 mmol / g. It is preferable to adjust to use.
The properties of these inorganic carriers are not particularly limited, but usually the average particle size is 5 to 200 μm, preferably 10 to 150 μm, the average pore size is 20 to 1000 mm, preferably 50 to 500 mm, and the specific surface area is 150 to 1000 m. ² / g, preferably 200-700 m ² / g, pore volume 0.3-2.5 cm ³ / g, preferably 0.5-2.0 cm ³ / g, apparent specific gravity 0.10-0 It is preferred to use an inorganic carrier having a density of .50 g / cm ³ .

  Of course, the above-mentioned inorganic carriers can be used as they are, but as a pretreatment, these carriers are trimethylaluminum, triethylaluminum, triisobutylaluminum, trihexylaluminum, tripropylaluminum, tributylaluminum, trioctylaluminum, tridecylaluminum, It can be used after contacting an organoaluminum compound such as diisobutylaluminum hydride or an organoaluminum oxy compound containing an Al—O—Al bond.

  The metallocene catalyst according to the present invention is a catalyst comprising a metallocene compound (A), a compound (B) that reacts with the metallocene compound (A) to form a cationic metallocene compound, and if necessary, a fine particle carrier (C). There are no particular limitations on the method of contacting each component in obtaining the above, and for example, the following methods can be arbitrarily employed.

(I) After contacting the metallocene compound (A) with the compound (B) that reacts with the metallocene compound (A) to form a cationic metallocene compound, the fine particle carrier (C) is contacted.
(II) After contacting the metallocene compound (A) with the fine particle carrier (C), the compound (B) that reacts with the metallocene compound (A) to form a cationic metallocene compound is contacted.
(III) After contacting the metallocene compound (A) with the compound (B) that generates a cationic metallocene compound and the fine particle carrier (C), the metallocene compound (A) is contacted.

Of these contact methods, (I) and (III) are preferred, and (I) is most preferred. In any contact method, usually in an inert atmosphere such as nitrogen or argon, generally aromatic hydrocarbons such as benzene, toluene, xylene and ethylbenzene (usually having 6 to 12 carbon atoms), heptane, hexane, decane and dodecane. In the presence of a liquid inert hydrocarbon such as an aliphatic or alicyclic hydrocarbon (usually having 5 to 12 carbon atoms) such as cyclohexane, a method of bringing each component into contact with stirring or non-stirring is employed.
This contact is usually −100 ° C. to 200 ° C., preferably −50 ° C. to 100 ° C., more preferably 0 ° C. to 50 ° C., for 5 minutes to 50 hours, preferably 30 minutes to 24 hours, more preferably. It is desirable to carry out in 30 minutes to 12 hours.

  In addition, as described above, certain components are soluble when contacting the metallocene compound (A), the compound (B) that reacts with the metallocene compound (A) to form a cationic metallocene compound and the fine particle carrier (C). Either an aromatic hydrocarbon solvent that is hardly soluble or an aliphatic or alicyclic hydrocarbon solvent in which a certain component is insoluble or hardly soluble can be used.

  In the case where the contact reaction between the components is performed stepwise, this may be used as it is as the solvent for the subsequent contact reaction without removing the solvent used in the previous step. In addition, after the previous catalytic reaction using a soluble solvent, liquid inert hydrocarbons in which certain components are insoluble or sparingly soluble (for example, aliphatics such as pentane, hexane, decane, dodecane, cyclohexane, benzene, toluene, xylene, etc.) Hydrocarbons, alicyclic hydrocarbons or aromatic hydrocarbons) and the desired product is recovered as a solid or once or part of the soluble solvent is removed by means such as drying. After removing the product as a solid, the subsequent catalytic reaction of the desired product can also be carried out using any of the inert hydrocarbon solvents described above. In this invention, it does not prevent performing contact reaction of each component in multiple times.

  In the present invention, the use ratio of the metallocene compound (A), the compound (B) that reacts with the metallocene compound (A) to form a cationic metallocene compound, and the fine particle carrier (C) is not particularly limited. A range is preferred.

When an organoaluminum oxy compound is used as the compound (B) that reacts with the metallocene compound (A) to form a cationic metallocene compound, the aluminum of the organoaluminum oxy compound relative to the transition metal (M) in the metallocene compound (A) is used. The atomic ratio (Al / M) is usually in the range of 1 to 100,000, preferably 5 to 1000, more preferably 50 to 200, and when a borane compound or a borate compound is used, transition in the metallocene compound The atomic ratio (B / M) of boron to metal (M) is usually selected within the range of 0.01 to 100, preferably 0.1 to 50, and more preferably 0.2 to 10.
Further, when a mixture of an organoaluminum oxy compound, a borane compound, and a borate compound is used as the compound (B) for generating a cationic metallocene compound, for each compound in the mixture, the transition metal (M) It is desirable to select at the same usage ratio as above.

  The fine particle carrier (C) is used in an amount of 0.0001-5 mmol, preferably 0.001-0.5 mmol, more preferably 0.01-0.1 mmol, of the transition metal in the metallocene compound (A). It is 1g per hit.

  The metallocene compound (A), the compound (B) that reacts with the metallocene compound (A) to form a cationic metallocene compound, and the fine particle carrier (C) are any of the contact methods (I) to (III). Then, the catalyst for olefin polymerization can be obtained as a solid catalyst by removing the solvent. The removal of the solvent is desirably performed under normal pressure or reduced pressure at 0 to 200 ° C., preferably 20 to 150 ° C. for 1 minute to 50 hours, preferably 10 minutes to 10 hours.

The metallocene catalyst can also be obtained by the following method.
(IV) The metallocene compound (A) and the fine particle carrier (C) are contacted to remove the solvent, which is used as a solid catalyst component, and an organoaluminum oxy compound, borane compound, borate compound or a mixture thereof under polymerization conditions Make contact.
(V) The organoaluminum oxy compound, borane compound, borate compound or a mixture thereof and the fine particle carrier (C) are contacted to remove the solvent, using this as a solid catalyst component, and the metallocene compound (A) under polymerization conditions Make contact.
In the case of the contact methods (IV) and (V), the same conditions as described above can be used for the component ratio, contact conditions, and solvent removal conditions.

In addition, as a component that also serves as the fine particle carrier (C) and the compound (B) that reacts with the metallocene compound (A), which is an essential component of the ethylene polymer production method of the present invention, to form a cationic metallocene compound, Silicates can also be used.
The layered silicate is a silicate compound having a crystal structure in which planes formed by ionic bonds or the like are stacked in parallel with each other with a weak binding force.
Most layered silicates are naturally produced mainly as the main component of clay minerals, but these layered silicates are not limited to natural ones and may be artificially synthesized.

  Among these, montmorillonite, sauconite, beidellite, nontronite, saponite, hectorite, stevensite, bentonite, teniolite and the like, smectite group, vermiculite group and mica group are preferable.

In general, natural products are often non-ion-exchangeable (non-swellable). In that case, in order to have preferable ion-exchange (or swellable), ion exchange (or swellable) is provided. It is preferable to perform the process for providing. Among such treatments, particularly preferred are the following chemical treatments.
Here, as the chemical treatment, any of a surface treatment for removing impurities adhering to the surface and a treatment that affects the crystal structure and chemical composition of the layered silicate can be used.
Specifically, (a) acid treatment performed using hydrochloric acid, sulfuric acid, etc., (b) alkali treatment performed using NaOH, KOH, NH _3, etc., (c) selected from Groups 2 to 14 of the periodic table Salt treatment with a salt comprising at least one anion selected from the group consisting of a cation containing at least one atom and a halogen atom or an anion derived from an inorganic acid, (d) alcohol, hydrocarbon Examples thereof include organic compounds such as compounds, formamide and aniline. These processes may be performed independently or two or more processes may be combined.

  The layered silicate can control the particle properties by pulverization, granulation, sizing, fractionation, etc. at any time before, during, or after all the steps. The method can be any purposeful. In particular, for granulation methods, for example, spray granulation method, rolling granulation method, compression granulation method, stirring granulation method, briquetting method, compacting method, extrusion granulation method, fluidized bed granulation Method, emulsion granulation method and submerged granulation method. Particularly preferable granulation methods are the spray granulation method, the rolling granulation method and the compression granulation method.

  Of course, the above-mentioned layered silicate can be used as it is, but these layered silicates are trimethylaluminum, triethylaluminum, triisobutylaluminum, tripropylaluminum, tributylaluminum, trihexylaluminum, trioctylaluminum, tridecylaluminum, It can be used in combination with an organoaluminum compound such as diisobutylaluminum hydride or an organoaluminum oxy compound containing an Al—O—Al bond.

In the metallocene catalyst according to the present invention, in order to support the metallocene compound (A) on the layered silicate, the metallocene compound (A) and the layered silicate are brought into contact with each other, or the metallocene compound (A) or organoaluminum compound. The layered silicates may be brought into contact with each other.
The contact method of each component is not specifically limited, For example, the following methods are arbitrarily employable.
(VI) The metallocene compound (A) and the organoaluminum compound are contacted and then contacted with the layered silicate support.
(VII) The metallocene compound (A) and the layered silicate support are contacted and then contacted with the organoaluminum compound.
(VIII) The organoaluminum compound and the layered silicate support are contacted and then contacted with the metallocene compound (A).

  Of these contact methods, (VI) and (VIII) are preferred. In any contact method, usually in an inert atmosphere such as nitrogen or argon, generally aromatic hydrocarbons such as benzene, toluene, xylene and ethylbenzene (usually 6 to 12 carbon atoms), heptane, hexane, decane and dodecane. In the presence of a liquid inert hydrocarbon such as an aliphatic or alicyclic hydrocarbon (usually having 5 to 12 carbon atoms) such as cyclohexane, a method of bringing each component into contact with stirring or non-stirring is employed.

The use ratio of the metallocene compound (A), the organoaluminum compound, and the layered silicate carrier is not particularly limited, but the following ranges are preferable.
The supported amount of the metallocene compound (A) is 0.0001 to 5 mmol, preferably 0.001 to 0.5 mmol, more preferably 0.01 to 0.1 mmol, per 1 g of the layered silicate support.
In the case of using an organoaluminum compound, the amount of Al supported is preferably in the range of 0.01 to 100 mol, preferably 0.1 to 50 mol, more preferably 0.2 to 10 mol.

For the method of supporting and removing the solvent, the same conditions as those for the inorganic carrier can be used.
When a layered silicate is used as a component that serves both as the catalyst component (B) and the component (C), the polymerization activity is high and the productivity of an ethylene-based polymer having a long chain branch is improved.
The olefin polymerization catalyst thus obtained may be used after the prepolymerization of the monomer if necessary.

  As an example of producing a metallocene catalyst, for example, by referring to “catalyst” and “mixing ratio and conditions of raw materials” described in JP-T-2002-535339 and JP-A-2004-189869, which are publicly known publications, Can be manufactured. The index of the polymer can be controlled by various polymerization conditions, and can be controlled by, for example, the methods described in JP-A-2-269705 and JP-A-3-21607.

  The polyethylene of the present invention is obtained by homopolymerization of ethylene, or ethylene and an α-olefin having 3 to 12 carbon atoms, such as propylene, 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1- Obtained by copolymerization with octene or the like. Also, copolymerization with a diene for the purpose of modification is possible. Examples of the diene compound used at this time include butadiene, 1,4-hexadiene, ethylidene norbornene, dicyclopentadiene, and the like. The comonomer content during the polymerization can be arbitrarily selected. For example, in the case of copolymerization of ethylene and an α-olefin having 3 to 12 carbon atoms, an ethylene / α-olefin copolymer is used. The α-olefin content therein is 0 to 40 mol%, preferably 0 to 30 mol%.

The molecular weight of the produced polymer can be adjusted to some extent by changing the polymerization conditions such as the polymerization temperature and the molar ratio of the catalyst, but the molecular weight can be adjusted more effectively by adding hydrogen to the polymerization reaction system. Can do.
Moreover, even if a component for the purpose of removing moisture, a so-called scavenger, is added to the polymerization system, the polymerization can be carried out without any trouble.
Such scavengers include organoaluminum compounds such as trimethylaluminum, triethylaluminum and triisobutylaluminum, the organoaluminum oxy compounds, modified organoaluminum compounds containing branched alkyl, organozinc compounds such as diethyl zinc and dibutyl zinc, diethyl Organic magnesium compounds such as magnesium, dibutylmagnesium and ethylbutylmagnesium, and grinier compounds such as ethylmagnesium chloride and butylmagnesium chloride are used. Of these, triethylaluminum, triisobutylaluminum, and ethylbutylmagnesium are preferable, and triethylaluminum is particularly preferable.
The present invention can also be applied to a multistage polymerization system having two or more stages having different polymerization conditions such as hydrogen concentration, monomer amount, polymerization pressure, and polymerization temperature without any trouble.

  The polyethylene of the present invention can be produced by a production process such as a gas phase polymerization method, a solution polymerization method, or a slurry polymerization method, preferably a slurry polymerization method. Among the polymerization conditions of the polyethylene of the present invention, the polymerization temperature can be selected from the range of 0 to 200 ° C. In slurry polymerization, polymerization is performed at a temperature lower than the melting point of the produced polymer. The polymerization pressure can be selected from the range of atmospheric pressure to about 10 MPa. It is selected from aliphatic hydrocarbons such as hexane and heptane, aromatic hydrocarbons such as benzene, toluene and xylene, alicyclic hydrocarbons such as cyclohexane and methylcyclohexane, etc. in a state where oxygen and water are substantially cut off. It can be produced by slurry polymerization of ethylene and α-olefin in the presence of an inert hydrocarbon solvent.

  As long as the polyethylene of the present invention satisfies the range specified in the present invention, polymerization is successively performed in a single polymerizer, a plurality of reactors connected in series or in parallel, and a plurality of ethylene polymers are polymerized separately. It may be mixed later.

  The ethylene used in the polyethylene of the present invention may be ethylene produced from crude oil derived from ordinary fossil raw materials, or may be ethylene derived from plants. Examples of the plant-derived ethylene and polyethylene include ethylene and polymers thereof described in JP-T 2010-511634. Plant-derived ethylene and its polymers have the property of carbon neutral (does not use fossil raw materials and does not lead to an increase in carbon dioxide in the atmosphere), and can provide environmentally friendly products.

3. Uses and properties of polyethylene The polyethylene for container lids of the present invention is further characterized by satisfying the following properties (i) to (iv).
Property (i): Flexural modulus is 850 MPa or more.
Characteristic (ii): Tensile yield strength is 25 MPa or more.
Characteristic (iii): Constant strain ESCR is 10 to 50 hours.
Characteristic (iv): The peak top time in isothermal crystallization at 121.5 ° C. measured by a differential scanning calorimeter (DSC) is 80 seconds or less.
Characteristic (v): The shrinkage ratio anisotropy (MD / TD) of the injection molded plate of 120 × 120 × 2 mm is 1.0 to 1.8.
Characteristic (vi): The hydrocarbon volatile content is 80 ppm or less.

The flexural modulus of the polyethylene of the present invention is 850 MPa or more, preferably 900 MPa or more, and more preferably 980 MPa or more. When the flexural modulus is less than 850 MPa, the rigidity is lowered, and the container lid is easily deformed by the internal pressure of the container, and particularly at high temperatures. Although the upper limit of a bending elastic modulus is not specifically limited, Usually, it is 2000 MPa or less.
Here, the flexural modulus is a value measured according to JIS K6922-2 using a 4 × 10 × 80 mm plate injection-molded at 210 ° C. as a test piece.
The flexural modulus can be adjusted by increasing or decreasing the molecular weight and density of polyethylene, and the flexural modulus can be increased by increasing the molecular weight or density.

The tensile yield strength of the polyethylene of the present invention is 25 MPa or more, preferably 26 MPa or more, more preferably 27 MPa or more. When the tensile yield strength is less than 25 MPa, the rigidity is lowered, and the feel when the cap is opened becomes soft. The upper limit of the tensile yield strength is not particularly limited, but is usually 50 MPa or less.
Here, the tensile yield strength is a value measured according to JIS K6922-2: 1997, using a JIS No. 1 tensile test piece injection molded at 210 ° C. as a test piece.
The tensile yield strength can be adjusted by increasing or decreasing the molecular weight and density of the polyethylene, and increasing the molecular weight or density can increase the tensile yield strength.

  The constant strain ESCR of the polyethylene of the present invention is 10 hours or more and 50 hours or less. It is desirably 15 hours or more and 50 hours or less, and more desirably 20 hours or more and 50 hours or less. If this value is less than 10 hours, it will not withstand the internal pressure of the container during product storage and will be destroyed. Moreover, since the thing over 50 hours cannot satisfy other requirements, it is not realistic. In order to increase the constant strain ESCR, adjustment is possible by controlling the molecular weight, density, and molecular weight distribution.

  The peak top time in isothermal crystallization at 121.5 ° C. measured with a differential scanning calorimeter (DSC) of the polyethylene of the present invention is preferably 80 seconds or less. When this value exceeds 80 seconds, the molding speed is delayed and the molding cycle becomes longer. This value can be adjusted by density and molecular weight. Outside the range specified by the present invention, when the MFR is high, the density is low, and the blending amount is small, the isotherm at 121.5 ° C. measured with a differential scanning calorimeter (DSC) of the polyethylene resin composition. The peak top time in crystallization exceeds 80 seconds. In addition, when the MFR is low, the density is high, and the blending amount is large outside the range defined by the present invention, the reality cannot be satisfied because other requirements such as rigidity, moldability, and stress crack resistance cannot be satisfied. No.

  The MD / TD of the shrinkage ratio anisotropy during the injection molding of the polyethylene of the present invention is 1.0 to 1.8. This value is formed by injection molding at 190 ° C to form a flat plate of 120 x 120 x 2 mm. After adjusting the condition at 23 ° C for 48 hours, the dimensions in the flow direction (MD) and the right angle direction (TD) are measured, and the shrinkage The rate is obtained by dividing the MD value by the TD value. If this value exceeds 1.8, the product tends to break, whereas if it is less than 1.0, the product tends to deform. The shrinkage rate anisotropy can be adjusted by molecular weight distribution.

The hydrocarbon volatile content of the polyethylene of the present invention is preferably 80 ppm or less, more preferably 50 ppm or less, and still more preferably 30 ppm or less. The hydrocarbon referred to in the present invention refers to a compound containing at least carbon and hydrogen, and is usually measured by gas chromatography. By satisfying this requirement of the present invention, the odor and taste of the container contents Can prevent the impact on.
Here, hydrocarbon volatile matter is measured by gas chromatography of the air in the head space when 1 g of polyethylene resin is put in a 25 ml glass sealed container and heated at 130 ° C. for 60 minutes.
In the present invention, in order to reduce the hydrocarbon volatile content to a predetermined value or less, the polymerized polyethylene polymer is subjected to a volatile content removal operation, such as steam stripping treatment, hot air deodorization treatment, vacuum treatment, nitrogen purge treatment, etc. By carrying out the above, it can be achieved, and in particular, by performing the steam deodorization treatment, the effect of the present invention can be remarkably exhibited. The conditions for the steam treatment are not particularly limited, but the ethylene polymer may be brought into contact with 100 ° C. steam for about 8 hours.

The static friction coefficient of the polyethylene of the present invention is preferably 0.30 or less, more preferably 0.25 or less, and still more preferably 0.23 or less. This value is a dimensionless value. It can be measured with a commercially available friction coefficient measuring instrument. The lower limit of this value is not particularly limited, but is usually 0.10 or more. If this value exceeds 0.30, the opening and closing properties of the container lid will be adversely affected.
This static friction coefficient can be adjusted by the density, molecular weight and molecular weight distribution of polyethylene. When the density of the polyethylene resin is lowered from the range specified in the present invention, the density is deteriorated, and when the molecular weight distribution is further broadened and the HLMFR is further increased, the density may be deteriorated.

The tensile fracture nominal strain of the polyethylene of the present invention is preferably 200% or less, more preferably 150% or less, and still more preferably 100% or less. If this value exceeds 200%, the bridging property of the container lid may be reduced and the function may not be performed.
The tensile fracture nominal strain of the polyethylene of the present invention can be adjusted by the molecular weight distribution. If the melt flow rate ratio of polyethylene is smaller than the range of the present invention, the molecular weight distribution becomes narrow and the tensile strain nominal strain becomes large.

According to a conventional method, the above polyethylene can be pelletized by mechanical melt mixing with a pelletizer, a homogenizer or the like, and then molded by various molding machines to obtain a desired molded product.
In addition, in addition to other olefin polymers and rubbers, etc., the polyethylene for container lids obtained by the above method may be used in addition to antioxidants, ultraviolet absorbers, light stabilizers, lubricants, antistatic agents, Known additives such as a clouding agent, an antiblocking agent, a processing aid, a color pigment, a crosslinking agent, a foaming agent, an inorganic or organic filler, and a flame retardant can be blended.
As additives, for example, one or more antioxidants (phenolic, phosphorus, sulfur), lubricants, antistatic agents, light stabilizers, ultraviolet absorbers, and the like can be used in combination as appropriate. As filler, calcium carbonate, talc, metal powder (aluminum, copper, iron, lead, etc.), silica, diatomaceous earth, alumina, gypsum, mica, clay, asbestos, graphite, carbon black, titanium oxide, etc. can be used. Of these, calcium carbonate, talc and mica are preferably used. In any case, the polyethylene resin composition can be blended with various additives as necessary and kneaded with a kneading extruder, a Banbury mixer, or the like to obtain a molding material.

In the present invention, it is also an effective technique to use a nucleating agent in order to further accelerate the crystallization rate of the container lid polyethylene.
As the nucleating agent, generally known nucleating agents can be used, and general organic or inorganic nucleating agents can be used. For example, dibenzylidene sorbitol or a derivative thereof, an organic phosphoric acid compound or a metal salt thereof, an aromatic sulfonate or a metal salt thereof, an organic carboxylic acid or a metal salt thereof, a rosin acid partial metal salt, an inorganic fine particle such as talc, an imide Amides, quinacridone quinones, or mixtures thereof.
Among them, a dibenzylidene sorbitol derivative, an organic phosphate metal salt, an organic carboxylic acid metal salt, and the like are preferable because they are excellent in transparency.
Specific examples of the dibenzylidene sorbitol derivative include 1,3: 2,4-bis (o-3,4-dimethylbenzylidene) sorbitol and 1,3: 2,4-bis (o-2,4-dimethylbenzylidene). Sorbitol, 1,3: 2,4-bis (o-4-ethylbenzylidene) sorbitol, 1,3: 2,4-bis (o-4-chlorobenzylidene) sorbitol, 1,3: 2,4-dibenzylidene Sorbitol is mentioned, and specific examples of the metal salt of benzoic acid include hydroxy-di (t-butylbenzoic acid) aluminum.

  When the nucleating agent is blended with the polyethylene of the present invention, the blending amount of the nucleating agent is preferably 0.01 to 5 parts by weight, more preferably 0.01 to 3 parts by weight, and still more preferably 100 parts by weight of polyethylene. Is 0.01 to 1 part by weight, particularly preferably 0.01 to 0.5 part by weight. If the nucleating agent is less than 0.01 parts by weight, the effect of improving the high-speed moldability is not sufficient. On the other hand, if it exceeds 5 parts by weight, there is a problem that the nucleating agent is likely to aggregate and form a lump.

Using the polyethylene of the present invention as a raw material, it is molded mainly by an injection molding method, a compression molding method or the like to obtain various molded products. Since the polyethylene of the present invention satisfies the above characteristics, it has high rigidity, impact resistance, stress crack resistance, slipperiness, low odor, food safety, openability, and closure performance, and high speed. It is possible to provide a moldable polyethylene resin.
Therefore, it can be used for applications such as containers and container lids that require such characteristics, and in particular, can be suitably used for beverage containers and container lids such as soft drinks and tea-based beverages.
In particular, a beverage container lid using the polyethylene of the present invention can be molded at high speed, made into a high cycle, and formed into a one-piece shape, and is suitably used for containers such as PET bottles.

Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to these examples as long as the gist thereof is not exceeded.
In addition, the measuring method used in the Example is as follows.
(1) Melt flow rate (MFR) at a temperature of 190 ° C. and a load of 2.16 kg:
Measured according to JIS K6922-2: 1997.
(2) Melt flow rate (HLMFR) at a temperature of 190 ° C. and a load of 21.6 kg:
Measured according to JIS K6922-2: 1997.
(3) Melt flow rate (MLMFR) at a temperature of 190 ° C. and a load of 11.1 kg:
Measured according to JIS K6922-2: 1997.
(4) Density:
The measurement was made according to JIS K6922-1, 2: 1997.
(5) Flexural modulus:
Using a 4 × 10 × 80 mm plate injection-molded at 210 ° C. as a test piece, measurement was performed in accordance with JIS K6922-2.

(6) Tensile yield strength:
Measured according to JIS K6922-2: 1997.
(7) Constant strain ESCR:
Measured according to JIS K6922-2: 1997.
(8) Crystallization time:
The sample was allowed to stand at 190 ° C. for 5 minutes using DSC-7 manufactured by Perkin Elmer, and then cooled to 121.5 ° C. at a rate of 120 ° C./min. The peak top was detected and measured when crystallization was completed at an isothermal temperature of 121.5 ° C.
(9) Hydrocarbon volatiles:
1 g of resin was placed in a 25 ml glass sealed container, and the components in the sealed container after heating at 130 ° C. for 60 minutes were analyzed by gas chromatography and measured.
(10) Coefficient of static friction:
With a FANUC ROBOSHOT S-2000i 100B injection molding machine, a 120 × 120 × 2 mm flat plate with a one-sided film gate (gate thickness 0.2 mm) was formed at a molding temperature of 190 ° C. and a mold temperature of 40 ° C. Thereafter, the sample was allowed to stand at 23 ° C. for 48 hours and then measured using a tribogear μs94i manufactured by Shinto Kagaku.

(11) Tensile fracture nominal strain:
Measured according to JIS K6922-2: 1997.
(12) Molding high cycle property evaluation:
A cup-shaped cylindrical container having a thickness of 0.8 mm, a height of 110 mm, and a diameter of 60 mm was injection-molded with a FANUC ROBOSHOT S-2000i 100B injection molding machine at a molding temperature of 190 ° C. and a mold temperature of 20 ° C. At this time, it was evaluated whether the mold can be released from the mold when the cooling time is shortened. The evaluation criteria are as follows, and indicated by ○, Δ, and ×.
○: Cooling time within 3 seconds △: Cooling time 3 to 6 seconds ×: Cooling time 6 seconds or more

(13) Measurement of molecular weight by gel permeation chromatography (GPC) (weight average molecular weight Mw):
It measured by the gel permeation chromatography (GPC) of the following conditions.
Apparatus: WATERS 150C
Column: 3 AD80M / S manufactured by Showa Denko KK Measurement temperature: 140 ° C
Concentration: 1 mg / 1 ml
Solvent: o-dichlorobenzene Calculation of molecular weight and column calibration were performed according to the following method.
GPC chromatographic data was loaded into a computer at a frequency of 1 point / second, and data processing was performed according to the description in Chapter 4 of “Size Exclusion Chromatography” published by Sadao Mori and Kyoritsu Publishing Co., and Mw value was calculated.
The column was calibrated by monodisperse polystyrene (S-7300, S-3900, S-1950, S-1460, S-1010, S-565, S-152, S-66.0, S-28 manufactured by Showa Denko KK. .5, S-5.05), a series of monodisperse polystyrene measurements using each 0.2 mg / ml solution of n-eicosane and n-tetracontane and the logarithm of their elution peak time and molecular weight A calibration curve was obtained by fitting the relationship with a quartic polynomial.
In addition, the molecular weight (MPS) of polystyrene was converted into the molecular weight (MPE) of polyethylene using the following formula.
MPE = 0.468 × MPS

(14) Shrinkage ratio anisotropy (MD / TD):
Using a Toshiba Machine IS-80 injection molding machine, a 120 × 120 × 2 mm flat plate with one side film gate (gate thickness 0.2 mm) was formed at a molding temperature of 190 ° C. and a mold temperature of 40 ° C. The flow direction (MD) and the flow right-angle direction (TD) after standing at 23 ° C. for 48 hours were measured. MD / TD was calculated from the measured value.
(15) Overall evaluation:
Comprehensive evaluation of suitability as a polyethylene resin composition for container lids was made and judged according to the following criteria.
○: No defective items (good)
×: There are defective items

[Example 1]
<Production of polymer with metallocene catalyst>
Metallocene catalyst described in Example 3 of JP-T-2002-535339, dimethylsilylenebis {1,1 ′-[2- (2-furyl) -4,5-dimethyl-cyclopentadienyl]} zirconium dichloride In accordance with a conventional method, an ethylene polymer was produced by the following method.

<Preparation of supported catalyst>
To 13.4 ml of toluene, 8.5 ml of a toluene solution of methylalumoxane (Albemarle, Al concentration: 2.93 mol / L) and dimethylsilylenebis {1,1 ′-[2- (2-furyl) -4,5- Dimethyl-cyclopentadienyl]} zirconium dichloride (70.6 mg) was added, and the mixture was stirred at room temperature for 30 minutes in the dark.
Next, 5.0 g of SiO ₂ (manufactured by GRACE, 948) previously calcined at 400 ° C. for 8 hours in a nitrogen atmosphere was added to the toluene solution, and the mixture was stirred at 40 ° C. for 1 hour. Thereafter, vacuum drying was performed while maintaining 40 ° C. to obtain a solid catalyst. The obtained solid catalyst was slurried with hexane and used for ethylene polymerization.

<Ethylene polymerization>
4 ml of a hexane dilution of triethylaluminum (Al concentration 0.1 mol / L) was added to an autoclave with an internal volume of 1.5 L purged with nitrogen, and 800 ml of isobutane was introduced. The internal temperature of the autoclave was raised to 80 ° C., and ethylene was introduced so that the ethylene partial pressure was 1.4 MPa. 7 ml of a solid catalyst hexane slurry (20 mg / ml) was introduced into an autoclave to initiate polymerization. During polymerization, 80 ° C. and ethylene partial pressure of 1.4 MPa were maintained. Further, in order to keep the hydrogen concentration during the polymerization constant, the hydrogen concentration in the gas phase part of the autoclave was measured, and the polymerization was continued while appropriately adding hydrogen. After 1 hour, the reaction was stopped by purging the internal pressure of the autoclave and isobutane.
As a result, 82 g of polymer was recovered. Further, the average hydrogen concentration during the polymerization was 0.12%.
The physical properties and evaluation results of the obtained polyethylene are shown in Table 1. The polyethylene was excellent in mechanical properties such as tensile yield strength, flexural modulus, and constant strain ESCR, and had a short crystallization time and excellent molding high cycle properties.

[Examples 2 and 3]
The same procedure as in Example 1 was performed except that the conditions were set so that the physical properties shown in Table 1 were obtained. The evaluation results of the obtained polymer are shown in Table 1. The obtained polymer was excellent in mechanical properties such as tensile yield strength, flexural modulus, and constant strain ESCR, and had a short crystallization time and excellent molding high cycle property.

[Comparative Examples 1-3]
The same procedure as in Example 1 was performed except that the conditions were set so that the physical properties shown in Table 2 were obtained. The evaluation results of the obtained polymer are shown in Table 2. As shown in Table 2, Comparative Example 1 has a longer crystallization time than Examples 1 to 3, resulting in poor molding high cycle performance, shrinkage ratio anisotropy, and the like. In Comparative Examples 2 and 3, the crystallization time was long and the molding high cycle property was poor.

  According to the present invention, it is suitable for a lid of a container for storing a liquid of a PET bottled beverage, has a high crystallization speed while maintaining high fluidity, stress crack resistance and rigidity, and has a shrinkage rate. A container lid with little anisotropy can be provided.

Claims (4)

Polymerized using a metallocene catalyst having a cyclopentadienyl ring and a heteroaromatic group, or a cyclopentadienyl ring and a fluorenyl ring, and containing a metallocene complex containing Ti, Zr or Hf, and A polyethylene for container lids that satisfies the requirements of characteristics (1) to (5) and characteristics (i) to (vi).
Characteristic (1): Melt flow rate (MFR) at a temperature of 190 ° C. and a load of 2.16 kg is 1 to 10 g / 10 min.
Characteristic (2): Melt flow rate (HLMFR) at a temperature of 190 ° C. and a load of 21.6 Kg is 80 to 400 g / 10 minutes.
Characteristic (3): Melt flow rate ratio (HLMFR / MFR) is 20-80.
Characteristic (4): The density is 0.955 to 0.965 g / cm ³ .
Characteristic (5): Mw measured by HLMFR and GPC satisfies the relationship of log [HLMFR] ≦ −3.85 log [Mw / 10,000] +6.0.
Property (i): Flexural modulus is 850 MPa or more.
Characteristic (ii): Tensile yield strength is 25 MPa or more.
Characteristic (iii): Constant strain ESCR is 10 to 50 hours.
Characteristic (iv): The peak top time in isothermal crystallization at 121.5 ° C. measured by a differential scanning calorimeter (DSC) is 80 seconds or less.
Characteristic (v): The shrinkage ratio anisotropy (MD / TD) of the injection molded plate of 120 × 120 × 2 mm is 1.0 to 1.8.
Characteristic (vi): The hydrocarbon volatile content is 80 ppm or less. The said metallocene catalyst contains the metallocene complex represented by the following general formula (II), The polyethylene for container lids of Claim 1 characterized by the above-mentioned.
_{^{Q (C 5 H 4-c}} R 1 c) (C 5 H 4-d R 2 d) MXY ··· (II)
(In the formula, Q represents a binding group that bridges two conjugated five-membered ring ligands, M represents Ti, Zr, or Hf, and X and Y are each independently hydrogen, halogen, C1-C20 hydrocarbon group, C1-C20 oxygen-containing hydrocarbon group, C1-C20 nitrogen-containing hydrocarbon group, C1-C20 phosphorus-containing hydrocarbon group, or C1-C1 And R ¹ and R ² each independently represent a hydrocarbon group having 1 to 20 carbon atoms, a halogen group, a halogen-containing hydrocarbon group having 1 to 20 carbon atoms, an alkoxy group, An aryloxy group, an oxygen-containing hydrocarbon group, a sulfur-containing hydrocarbon group, a silicon-containing hydrocarbon group, a phosphorus-containing hydrocarbon group, a nitrogen-containing hydrocarbon group, or a boron-containing hydrocarbon group, and two adjacent R ^1, two ^{R 2} are carbon atoms bonded to each 4 10 Good .c and d also form a ring, each 0 ≦ c ≦ 4,0 ≦ d ≦ 4, an integer satisfying.) The metallocene complex represented by the general formula (II) is a bridged metallocene complex containing, as R ^{1 to} R ² , at least one heterocyclic aromatic group in the compound. Item 3. The container lid polyethylene according to Item 2.   The polyethylene for container lids according to claim 3, wherein the heterocyclic aromatic group is selected from the group consisting of a furyl group, a benzofuryl group, a thienyl group, and a benzothienyl group.