JPH1160634A - Ethylene polymer having restrained amorphous portion - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain ethylene polymers excellent in moldability, sufficiently restrained in the amorphous portion and particularly excellent in ductile fracture resistance. SOLUTION: Ethylene polymers having a restrained amorphous portion are ethylene homopolymers or copolymers of ethylene and a 3-20C α-olefin having (A) a melt index, under a load of 2.16 kg at 190 deg.C, of 0.001-1,000 g/min, (B) a density of 0.90 g/cm<3> -0.985 g/cm<3> , (C) a molecular weight distribution, measured by gel permeation chromatography, of 3-7 and (D) a ratio (T2a /T2c ) of the spin-spin relaxation time T2a (microsecond) of the amorphous portion, measured by the<1> H pulsed NMR at 40 deg.C to the spin-spin relaxation time T2c (microsecond)of the crystalline portion, being not greater than 7.2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ethylene polymer having excellent moldability and having a restricted amorphous portion.

[0002]

2. Description of the Related Art Polyolefins, particularly polyethylene, are lightweight and economical, and thus are easily molded by melt molding such as extrusion molding, blow molding and injection molding, and are widely used. However, polyethylene that has been polymerized with a Ziegler catalyst, which has been widely used in the past, is satisfactory in terms of moldability, but has mechanical properties,
In particular, environmental stress crack resistance (hereinafter referred to as "ESCR").
Is inadequate. In particular, in the case of large-sized molded products, it is necessary to increase the rigidity of polyethylene, and even in such high-rigidity polyethylene, an ethylene polymer excellent in ESCR is demanded.

On the other hand, a so-called Phillips catalyst in which chromium oxide is supported on an inorganic oxide solid has excellent moldability, but has poor mechanical properties. Using these conventional ethylene polymers, intensive studies were conducted on various mechanical properties and the solid structure of the ethylene polymer, and the following was found. The amorphous part in the conventional ethylene polymer is not sufficiently constrained, and the ethylene polymer having such an amorphous part easily deforms due to an external force such as tension, and as a result, the ethylene polymer Was found to be extremely fragile.

In recent years, attempts have been made to produce an ethylene polymer having improved mechanical properties by using a catalyst prepared from a metallocene compound and an aluminoxane, etc. JP-A-58-19309, JP-A-60-350006, and JP-A-60-35006. 3
5007, 61-130314, 61-22120
8, 62-121709 and 62-121711. These attempts attempt to control the insertion of comonomer in the ethylene polymer and control the crystal parts in the ethylene polymer. In these ethylene polymers, the insertion of the comonomer into the molecule is very controlled. Further, in the solid structure of these ethylene polymers, the amorphous part is restricted and the mechanical properties are excellent. However, these ethylene polymers have a narrow molecular weight distribution, so that their moldability is not satisfactory.

Further, a constrained geometry addition catalyst (Japanese Patent Laid-Open Publication No.
An attempt has been made to produce an ethylene polymer which satisfies both moldability and mechanical properties by keeping the molecular weight distribution narrow and inserting long-chain branches into the molecule according to JP-A-3088. However, the ethylene polymer obtained when this catalyst is used in a solution polymerization method has a problem that it is inferior to ESCR as compared with an ethylene polymer using a Ziegler catalyst having the same melt index.

[0006]

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has as its object to provide a specific ethylene polymer having excellent moldability and mechanical properties.

[0007]

Means for Solving the Problems As a result of intensive studies, the present inventors have found an ethylene polymer which is excellent in moldability and whose amorphous portion is restricted, and has reached the present invention. The present invention relates to an ethylene polymer satisfying the following conditions (A) to (D). That is, it is an ethylene homopolymer or a copolymer of ethylene and an α-olefin having 3 to 20 carbon atoms, and (A) a melt index (hereinafter referred to as “MI”) at 190 ° C. under a load of 2.16 kg. .0
01-1000 g / 10 min, (B) density 0.90 g / c
m ³ -0.985 g / cm ³ , (C) molecular weight distribution (hereinafter referred to as “Mw / Mn”) measured by gel permeation chromatography (hereinafter referred to as “GPC”) of 3 to 7, (D ) Spin-spin relaxation time T _2c (microsecond) of crystal part determined by ¹ H pulse NMR at 40 ° C.
And amorphous part spin-spin relaxation time T _2a (microseconds)
And a ratio T _2a / T _{2c of} not more than 7.2.

Hereinafter, the present invention will be described in detail. The ethylene polymer of the present invention is an ethylene homopolymer or a random copolymer of ethylene and an α-olefin having 3 to 20 carbon atoms, preferably 4 to 20 carbon atoms. Examples of the α-olefin having 3 to 20 carbon atoms include propylene, butene-1, pentene-1,3-methylbutene-1, hexene-1,4-methylpentene-1, octene-1, decene-1, tetradecene-1, hexadecene-1, octadecene-1, eicocene-1. Etc. can be used. Further, vinyl compounds such as vinylcyclohexane or styrene and derivatives thereof can also be used. If necessary, a tertiary random polymer containing a small amount of a non-conjugated polyene such as 1,5-hexadiene and 1,7-octadiene may be used.

The MI of the ethylene polymer of the present invention is 0.0
01 to 1000 g / 10 min, preferably 0.005 to 6
The range is 00 g / 10 minutes. MI is 0.001g / 1
Ethylene polymers of less than 0 minutes cannot be produced with the particular catalyst used in the present invention. On the other hand, MI is 1000
If it exceeds g / 10 minutes, the strength of the molded article will be reduced.
MI was measured at 190 ° C. under a load of 2.16 kg in accordance with ASTM D1238.

The density of the ethylene polymer of the present invention is 0.90
^{g / cm 3 ~0.985g / cm 3} , preferably 0.9
It is in the range of ^{15g / cm 3 ~0.980g / cm 3} .
The density here is a value obtained by measuring the molded product as it is using a density gradient tube. Ethylene polymers having a density greater than 0.985 g / cm ³ cannot be produced with the particular catalyst used in the present invention. The ethylene polymer of the present invention needs to be manufactured under specific manufacturing conditions, that is, it is necessary to manufacture the ethylene polymer in a slurry state. If the density is less than the lower limit, the ethylene polymer cannot be manufactured in a slurry state. / Mn becomes narrow.

Further, the ethylene polymer of the present invention has a Mw / M
As for n, Mw / Mn measured by GPC is in the range of 3 to 7, preferably 3.5 to 7. When Mw / Mn is less than 3, the ethylene polymer has insufficient moldability, and when Mw / Mn exceeds 7, there is a problem that the mechanical properties of the ethylene polymer deteriorate. Incidentally, 21.6 kg at 190 ° C.
The melt index at load is 2.1 at 190 ° C.
The value obtained by dividing by the melt index at 6 kg load is 19 ~
It is preferable to set the molecular weight distribution of the ethylene polymer so as to have a range of 40. The measuring device used for the measurement of GPC is 150-C ALC manufactured by Waters.
/ GPC, column: AT-80 manufactured by Shodex
7S and TSK-gelGMH-H6 manufactured by Tosoh Corporation are used in series.
Measured in ° C. In the present invention, the above range Mw / M
In order to satisfy n, a production method of polymerizing an ethylene polymer in a slurry state using a specific catalyst was used.

The ethylene polymer of the present invention needs to have a specific solid structure. That is, ¹ H at 40 ° C.
The ratio T _2a / T _2c between the spin-spin relaxation time T _2c (microsecond) of the crystal part and the spin-spin relaxation time T _2a (microsecond) of the amorphous part, which is determined by pulse NMR, needs to be 7.2 or less. Here, the spin-spin relaxation time is a measure of the mobility of each part. As the thickness of the crystal part increases, the relaxation time of the crystal part decreases. On the other hand, if the amorphous part is sufficiently constrained by the crystal part, the relaxation time of the amorphous part is short, but for example, when the thickness distribution of the crystal part is wide, some of the amorphous part is sufficiently And the relaxation time of the amorphous portion of the ethylene polymer is prolonged. If the ratio of the relaxation time exceeds 7.2, the constraint of the amorphous part becomes insufficient,
The mechanical properties of the ethylene polymer become poor. It is preferably 6.5 or less, more preferably 6 or less.

The relaxation time is described in, for example, J. Nishi et al. Ch
em. Phys. , 82, 9 (1985), for example, the decay curve of spin-spin relaxation time (FID) obtained by the solid echo method is separated into two components by a least square method using a computer. Components that rapidly decay in a short time belong to the crystal part, and components that decay for a long time belong to the amorphous part, and the attenuation curve is fitted using the following equation to determine the relaxation time of each part. _{L 1 exp (-t / T 2c} ) + L 2 exp (-t / T 2c)
² (where t is time, L ₁ + L ₂ = 1) Further, it is preferable that T _2c is 10 microseconds or less. If this value exceeds 10 microseconds, the rigidity of the ethylene polymer decreases.

Further, it has already been reported that the thickness of the crystal part has a correlation with the tie molecule in the ethylene polymer,
The larger the amount of this tie molecule in the ethylene polymer, the more particularly the E
The durability against ductile fracture such as SCR is improved. That is, an ethylene homopolymer having a melt index at 190 ° C. under a load of 2.16 kg and a density of Yg / cm ³ at a load of Xg / 10 min, and a melt index at 190 ° C. under a load of 2.16 kg under a load of Xcg / 10 min and a density of Ycg /
In the ethylene copolymer of cm ³ , the peak frequency ν (c) of the acoustic band (hereinafter, referred to as “LAM”) in the primary long axis direction determined by laser Raman spectroscopy.
m ^-1 ) is preferably represented by the following formula. 0.0768 × LogX + 30 (Y−Yc) +10.3 (cm ⁻¹ ) <ν (cm
^-1 ) [However, in the case of ethylene homopolymer, 0.0768 x LogX +
10.3 (cm ^-1 ) <ν (cm ^-1 )]

The LAM band has a correlation with the thickness of the crystal part in the ethylene polymer.
al of Polymer Science: Pol
ymer Physics Edition, 19,
1593-1609 (19783). The tendency is that the higher the frequency of this LAM, the thinner the lamellar thickness of the ethylene polymer. When the density of the ethylene polymer is reduced by adding a comonomer in the conventional ethylene polymer, the density of the ethylene polymer is certainly reduced, but the crystal part is still thick and as a result, the tie in the ethylene polymer is reduced. The amount of molecules is small. In the laser Raman spectroscopy analysis of the present application, a Ramaonor T-6400 type was used, and the light source laser power was 300 mW.
Argon laser, measurement arrangement 90 degree scattering, spectrometer 64
A 0 mm triple monochromator, a slit 50 micrometer, and a detector Yvon 1024 × 256 were used.

Next, a method for producing the ethylene polymer of the present invention will be described. The ethylene polymer of the present invention comprises at least (A)
Using a supported catalyst prepared from a carrier material, (a) an organoaluminum compound, (c) a borate compound having active hydrogen, and (d) a titanium compound η-bonded to a cyclopentadienyl or substituted cyclopentadienyl group. Ethylene in a slurry state or ethylene and carbon number 3-20
Obtained by copolymerizing an α-olefin of the formula (1).

The carrier substance (A) may be either an organic carrier or an inorganic carrier. As the organic carrier, preferably (1) an α-olefin polymer having 2 to 10 carbon atoms,
For example, polyethylene, polypropylene, polybutene-1, ethylene-propylene copolymer, ethylenebutene-1 copolymer, ethylene-hexene-1 copolymer, propylenebutene-1 copolymer, propylenedivinylbenzene copolymer (2) an aromatic unsaturated hydrocarbon polymer,
For example, polystyrene, styrene divinylbenzene copolymer, and (3) a polymer containing a polar group, for example, polyacrylate, polymethacrylate, polyacrylonitrile, polyvinyl chloride, polyamide, polycarbonate and the like can be mentioned.

As the inorganic carrier, (4) an inorganic oxide,
For example, SiO ₂ , Al ₂ O ₃ , MgO, TiO ₂ , B
₂ O ₃ , CaO, ZnO, BaO, ThO, SiO ₂ −
MgO, SiO ₂ —Al ₂ O ₃ , SiO ₂ —MgO, S
(5) inorganic halogen compounds, such as MgCl ₂ , AlCl ₃ , MnCl _2, etc .; (6) inorganic carbonates, sulfates, nitrates, such as Na ₂ CO ₃ , iO ₂ -V ₂ O _5, etc.
K ₂ CO ₃ , CaCO ₃ , MgCO ₃ , Al ₂ (S
O ₄ ) ₃ , BaSO ₄ , KNO ₃ , Mg (NO ₃ )
_2, etc., (7) inorganic hydroxides such as, Mg (O
H) ₂ , Al (OH) ₃ , Ca (OH) _{2 and the} like. The most preferred support material is silica. The particle size of the carrier is arbitrary, but is generally 1 to 3000 µm, preferably 5 to 2000 µm, more preferably 10 to 100 µm.
0 μm.

The carrier material is treated with an organoaluminum compound (a). Examples of preferred organoaluminum compounds include trimethylaluminum, triethylaluminum, triisobutylaluminum, trihexylaluminum, trioctylaluminum, tridecylaluminum, diethylaluminummonochloride,
Alkyl aluminum hydrides such as diisobutylaluminum monochloride, ethylaluminum sesquichloride, ethylaluminum dichloride, diethylaluminum hydride, diisobutylaluminum hydride, diethylaluminum ethoxide, dimethylaluminum trimethylsiloxide, dimethylaluminum phenoxide, etc. And alumoxanes such as xane, ethylaluminoxane, isobutylaluminoxane and methylisobutylalumoxane. Of these, trialkylaluminum, aluminum alkoxide and the like are preferable. Most preferred are trimethylaluminum, triethylaluminum, and triisobutylaluminum.

Further, in the supported catalyst used in the method for producing an ethylene polymer of the present invention, a borate compound having active hydrogen represented by the following general formula is used. This borate compound is an activator for converting (d) to a cation by reacting with a titanium compound (d) η-bonded to a cyclopentadienyl or substituted cyclopentadienyl group, and Group having active hydrogen (T
-H) forms a chemical bond or a physical bond with the carrier when the borate compound is carried on the carrier substance.

[B ^- Qn (Gq (TH) r) z] A ⁺ where B represents boron. G represents a multi-bonded hydrocarbon radical, and preferred multi-bonded hydrocarbons are alkylene having 1 to 20 carbon atoms, arylene, and ararylene radicals.
Phenylene, bisphenylene, naphthalene, methylene,
Ethylene, 1,3-propylene, 1,4-butadiene,
p-phenylenemethylene and the like. The multi-bond radical G is an r + 1 bond, ie, one bond is bonded to a borate anion, and the other bond r of G is (TH)
Binds to a group.

T in the above general formula is -O-, -S-, -N
Represents R- or -PR-, wherein R represents a hydrocarbanyl radical, a trihydroicarbanylsilyl radical, a trihydrocarbanylgermanium radical, or a hydride. q is 1 or more, and preferably 1. The TH group includes -OH, -SH, -NR
H or -PRH, wherein R is a hydrocarbanyl radical having 1 to 18 carbon atoms, preferably 1 to 10 carbon atoms, or hydrogen. Preferred R groups are alkyl, cycloalkyl, allyl, allylalkyl or C 1 -C
18 alkylallyl. -OH, -SH, -NR
H or -PRH is, for example, -C (O) -OH, -C
(S) -SH, -C (O) -NRH, and C (O) -P
RH may be used. The most preferred group having active hydrogen is an -OH group. Q is hydride, dihydrocarbylamide, preferably dialkylamide, halide, hydrocarbyl oxide, alkoxide, allyl oxide, hydrocarbyl, substituted hydrocarbyl radical and the like. Here, n + z is 4.

[B ^- Qn (Gq (TH)]
r) z] include, for example, triphenyl (hydroxyphenyl) borate, diphenyldi (hydroxyphenyl) borate, triphenyl (2,4-dihydroxyphenyl) borate tri (p-tolyl) (hydroxyphenyl) borate, tris (pentafluorophenyl) ) (Hydroxyphenyl) borate, tris (2,
4-dimethylphenyl) (hydroxyphenyl) borate, tris (3,5-dimethylphenyl) (hydroxyphenyl) borate, tris (3,5-ditrifluoromethylphenyl) (hydroxyphenyl) borate, tris (pentafluorophenyl) (2-hydroxyethyl) borate, tris (pentafluorophenyl) (4-hydroxybutyl) borate, tris (pentafluorophenyl) (4-hydroxy-cyclohexyl) borate, tris (pentafluorophenyl) (4- (4 ^, - Hydroxyphenyl) phenyl) borate, tris (pentafluorophenyl) (6-hydroxy-2-naphthyl) borate and the like, most preferably tris (pentafluorophenyl) (4-hydroxyphenyl) Is the rate. Further, those in which the -OH group of the borate compound is substituted with -NHR (where R is methyl, ethyl, t-butyl) are also preferable.

Examples of the counter cation of the borate compound include a carbonium cation, a tropylluium cation, an ammonium cation, an oxonium cation, a sulfonium cation, and a phosphonium cation. In addition, metal cations and organic metal cations whose self-confidence is easily reduced are also exemplified. Specific examples of these cations include triphenylcarbonium ion, diphenylcarbonium ion, cycloheptatrinium, indenium, triethylammonium, tripropylammonium, tributylammonium, dimethylammonium,
Dipropyl ammonium, dicyclohexylammonium, trioctylammonium, N, N-dimethylammonium, diethylammonium, 2,4,6-pentamethylammonium, N, N-dimethylbenzylammonium, di- (i-propyl) ammonium, dicyclohexylammonium, Triphenylphosphonium, triphosphonium, tridimethylphenylphosphonium,
Tri (methylphenyl) phosphonium, triphenylphosphonium ion, triphenyloxonium ion,
Examples include triethyloxonium ion, pyrium, silver ion, gold ion, platinum ion, copper ion, palladium ion, mercury ion, and ferrocenium ion. Of these, ammonium ions are particularly preferred.

In the present invention, a titanium compound (d) bonded to a cyclopentadienyl or substituted cyclopentadienyl group represented by the following general formula by η-bonding is used.

Embedded image

Here, Ti is a titanium atom in an oxidation state of +2, +3, +4, Cp is a cyclopentadienyl or substituted cyclopentadienyl group which is η-bonded to titanium, X1 is an anionic ligand, X2 is a neutral conjugated diene compound. n + m is 1 or 2, Y is —O—, —S—, —NR— or —PR—, and Z is SiR ₂ , CR ₂ , SiR ₂ —SiR ₂ , CR ₂ C
R ₂ , CR = CR, CR ₂ SiR ₂ , GeR ₂ , BR ₂
R is in each case hydrogen, hydrocarbyl,
It is selected from silyl, germum, cyano, halo, or combinations thereof and combinations thereof having up to 20 non-hydrogen atoms.

The substituted cyclopentadienyl group includes 1
At least one hydrocarbyl having 1 to 20 carbon atoms,
Halohydrocarbyl having 1 to 20 carbon atoms, halogen or hydrocarbyl substitution having 1 to 20 carbon atoms, cyclopentadienyl substituted with a group 14 metalloid group, indenyl, tetrahydroindenyl, fluorenyl or octafluorenyl, Preferably 1 to 6 carbon atoms
Is a cyclopentadienyl group substituted with an alkyl group.

As X1 and X2, for example, in the above general formula, when n is 2, m is 0, and the oxidation number of titanium is +4, X1 is selected from methyl and benzyl, and n is 1, m
Is 0 and the oxidation number of titanium is +3, X1 is 2- (N,
If N-dimethyl) aminobenzyl and the oxidation number of titanium are +4, X1 is 2-butene-1,4-diyl, and if n is 0, m is 1 and the oxidation number of titanium is +2, X2 is 1,4. Diphenyl-1,3-butadiene or 1,3-pentadiene.

The catalyst of the present invention is obtained by adding component (a) to component (a).
It is obtained by supporting the component (c) and the component (d). The method of supporting the component (d) from the component (a) is arbitrary, but generally, the component (a), the component (c) and A method of dissolving the component (d) in an inert solvent in which each can be dissolved, mixing with the component (a), and then distilling off the solvent. Also, the component (a), the component (c) and the component (d) Is dissolved in an inert solvent, and then the solid is not precipitated, but the concentrate is concentrated, and the following amount of the concentrate is added to the component (A) in an amount capable of retaining the whole amount in the particles. A method of first supporting (a) and the component (c), and then supporting the component (d), a method of sequentially supporting the component (a), the component (d) and the component (c) on the component (a), (A), a method of supporting components (a), (c) and (d) by co-grinding Etc. are exemplified.

The component (c) and the component (d) of the present invention are generally solids, and the component (a) has a pyrophoric property. May be diluted before use. As the inert solvent used for this purpose, for example, propane, butane, pentane,
Aliphatic hydrocarbons such as hexane, heptane, octane, decane, dodecane and kerosene; alicyclic hydrocarbons such as cyclopentane, cyclohexane and methylcyclopentane; aromatic hydrocarbons such as benzene, toluene and xylene; and ethyl chloride; Examples thereof include halogenated hydrocarbons such as chlorobenzene and dichloromethane, and mixtures thereof. Such an inert hydrocarbon solvent is desirably used after removing impurities such as water, oxygen, and sulfur using a desiccant, an adsorbent, or the like.

For each gram of component (a), (a) is Al
1 × 10 ^-5 to 1 × 10 ^-1 mol, preferably 1
× 10 ^-4 mol to 5 × 10 ^-2 mol, (c) is 1 × 10 ^-7 mol to 1 × 10 ^-3 mol, preferably 5 × 10 ^-7 mol to 5 ×
10 ^-4 mol, (d) is 1 × 10 ^-7 mol to 1 × 10 ^-3 mol, and preferably from 5 × 10 ^-7 mol to 5 × 10 ^-4 mol. Each amount to be used and the loading method are determined by activity, economy, powder characteristics, scale in the reactor, and the like. The obtained supported catalyst may be washed by a method such as decantation or filtration using an inert hydrocarbon solvent for the purpose of removing the organoaluminum compound, borate compound, and titanium compound that are not supported on the support. it can.

The above series of operations such as dissolving, contacting, washing, etc.
It is recommended to perform at a temperature in the range of −30 ° C. to 150 ° C. selected for each unit operation. A more preferable range of such a temperature is 0 ° C or higher and 100 ° C or lower. In the present invention, a series of operations for obtaining a solid catalyst is preferably performed in a dry inert atmosphere. The solid catalyst of the present invention,
It can be stored in a slurry state dispersed in an inert hydrocarbon solvent, or can be dried and stored in a solid state.

In carrying out the polymerization of the ethylene polymer, the polymerization pressure is generally 1 to 100 atm, preferably 3 to 30 atm, and the polymerization temperature is 20 to 115 ° C, preferably 50 to 105 ° C. It is suitable. However, the upper limit of the temperature is a temperature at which the produced ethylene-based polymer can substantially maintain a slurry state, and if it exceeds this value, the problem that the molecular terminal double bond of the ethylene polymer increases. There is. Such a maximum temperature may vary depending on the density of the ethylene-based copolymer to be produced and the solvent used.

As the solvent used in the slurry method, the inert hydrocarbon solvents described above in the present invention are suitable. In particular, isobutane, isopentane, heptane, hexane,
Octane and the like are preferred. The comonomer that can be used in the present invention is an α-olefin represented by the following general formula. H ₂ C ＝ CHR (wherein, R is an alkyl group having 1 to 18 carbon atoms or an aryl group having 6 to 20 carbon atoms, and the alkyl group is linear, branched or cyclic.)

Examples of such comonomers include, for example,
Propylene, 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-octene, 1-decene, 1-dodecene, 1-tetradecene, 1-hexadecene, 1-octadecene, 1-eicosene, Selected from the group consisting of vinylcyclohexane and styrene, a cyclic olefin having 3 to 20 carbon atoms, for example, cyclopentene, cycloheptene, norbornene, 5-methyl-2-
Norbornene, tetracyclododecene, and 2-methyl-1.4,5.8-dimethano-1,2,3,4,4a,
Selected from the group consisting of 5,8,8a-octahydronaphthalene, a linear, branched or cyclic diene having 4 to 20 carbon atoms, for example, 1,3-butadiene, 1,4-pentadiene, 1,5- Hexadiene, 1,4-hexadiene,
And cyclohexadiene. In the present invention, propylene, 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-
Octene, 1-decene, 1-dodecene, 1-tetradecene, 1-hexadecene, 1-octadecene, 1-eicosene and the like are preferred.

The catalyst according to the present invention is capable of polymerizing ethylene or ethylene and α-olefin by itself. However, in order to prevent poisoning of the solvent and the reaction system, an organic aluminum compound is added as an additional component. It is also possible to use. Examples of preferred organoaluminum compounds include alkylaluminums such as trimethylaluminum, triethylaluminum, triisobutylaluminum, trihexylaluminum, trioctylaluminum, tridecylaluminum; diethylaluminum monochloride, diisobutylaluminum monochloride, ethylaluminum sesquichloride, Alkyl aluminum hydrides such as ethylaluminum dichloride, diethylaluminum hydride and diisobutylaluminum hydride; aluminum alkoxides such as diethylaluminum ethoxide, dimethylaluminum trimethylsiloxide and dimethylaluminum phenoxide; methylalumoxane, ethylaluminoxane, isobutylaluminum Emissions include alumoxane such as methyl isobutyl alumoxane. Of these, trialkylaluminum, aluminum alkoxide and the like are preferable. Most preferred are trimethylaluminum, triethylaluminum and triisobutylaluminum.

The ethylene polymer of the present invention may be used alone or as a mixture. In particular, it is preferable to use a bimodal composition in which a high MI ethylene polymer and a low MI polymer are mixed. Blends with other polymers and inorganic materials such as fillers and talc, alloys, and may be modified using generally known modification techniques. Further, additives such as an antioxidant, a light stabilizer, and a release agent may be added. The ethylene polymer of the present invention is molded by a known molding method such as injection molding, blow molding, pipe, film, and compression molding.

[0038]

EXAMPLES The present invention will be described below with reference to examples, but these do not limit the scope of the present invention. Each physical property in the present invention was measured by the following method. MI is 190 ° C. according to ASTM D1238,
This is a value measured under a load of 2.16 kg. Moldability (MIR) MIR is measured at a temperature of 190
This is a value obtained by dividing the value of MI measured at a load of 21.6 kg at a temperature of 190 ° C. by the MI measured at a load of 2.16 kg at a temperature of 190 ° C. The larger this value is, the better the moldability is. Mw / Mn: The measuring device used for the measurement was Waters
150-C ALC / GPC, manufactured by Sh
Odex AT-807S and Tosoh TSK-ge
The measurement was performed at 140 ° C. by using 1GMH-H6 in series and using trichlorobenzene containing 10 ppm of Irganox 1010 as a solvent. A calibration curve was prepared using commercially available monodisperse polystyrene as a standard substance.

Raman analysis: Irganox 1010; 500 ppm was added to the ethylene polymer and granulated at 190 ° C. with a single screw extruder. The obtained pellet was melted at 200 ° C. and 100 kg / cm ² for 3 minutes by a press molding machine, and then cooled at 10 ° C./minute to produce a flat plate having a thickness of 2 mm. Using this flat plate as a measuring device, Ramao
or T-6400 type, light source laser power 300
The measurement was performed at 25 ° C. using an argon laser of mW, a measurement arrangement of 90 ° scattering, a spectroscope 640 mm triple monochromator, a slit of 50 μm, and a detector Yvon 1024 × 256, and the peak value of the frequency of the LAM band was obtained. . Mechanical properties (a) Rigidity: Since rigidity is determined by density, rigidity was evaluated by density. The density was measured on the flat plate used in the Raman analysis using a density gradient tube. (B) ESCR: The FCR measured by the BTM method according to the above-mentioned pellet JIS-K-6760 was used as the ESCR value.

Pulsed NMR: Ethylene polymer pellets were pressed at 200 ° C. and 100 kg / cm ² with a press molding machine.
The mixture was melted for 10 minutes and then cooled at 10 ° C./minute to obtain a 2 mm flat plate. The obtained flat plate was cut out, placed in a sample tube, and measured at 40 ° C. The pulse NMR was measured by using PC-20 manufactured by Bruker, and the pulse was measured by a solid echo method. The obtained decay curve of spin-spin relaxation is converted by a connected Autonics Transger, taken out to a computer, and then subjected to a least-squares method to quickly and quickly attenuate a component and a component that attenuates for a long time. The attenuation curve was fitted using the following equation to determine the relaxation time of each part. _{L 1 exp (-t / T 2c} ) + L 2 exp (-t / T 2c)
² (where t is time, L ₁ + L ₂ = 1)

(Example 1) 6.2 g (8.8 mmol)
Of triethylammonium tris (pentafluorophenyl) (4-hydroxyphenyl) borate was added to 4 l of toluene and stirred at 90 ° C. for 30 minutes. Next, 40 ml of a 1 mol / l toluene solution of trihexyl aluminum was added to the solution, and the mixture was stirred at 90 ° C. for 1 minute. on the other hand,
Silica P-10 (manufactured by Fuji Silysia, Japan) was treated with a nitrogen stream at 500 ° C. for 3 hours, and the silica after the treatment was 1.7 times.
and stirred. To this silica slurry solution was added the above-mentioned toluene solution of triethylammonium tris (pentafluorophenyl) (4-hydroxyphenyl) borate and trihexylaluminum, and the mixture was stirred at 90 ° C. for 3 hours. Next, 206 ml of a 1 mol / l toluene solution of trihexyl aluminum was added, and the mixture was further stirred at 90 ° C. for 1 hour. Thereafter, the supernatant was decanted five times using toluene at 90 ° C. to remove excess trihexyl aluminum. 0.218mol /
l dark purple titanium (N-1,1-dimethylethyl) dimethyl (1- (1,2,3,4,5, -eta)
-2,3,4,5-tetramethyl-2,4-cyclopentadien-1-yl) silanaminato) ((2-) N)
ISOPAR ^™ E of − (η ⁴ -1,3-pentadiene)
20 ml of a solution (manufactured by Exxon Chemical Co., USA) was added to the above mixture and stirred for 3 hours to obtain a green supported catalyst. A part of the obtained supported catalyst was put in a 1.5-liter reactor whose inside was degassed under vacuum and purged with nitrogen together with 0.8 liter of dehydrated and deoxygenated hexane. With the temperature in the container at 75 ° C., a mixed gas of ethylene, 1-butene and hydrogen (gas composition is 700 g of ethylene,
1-butene 25g, hydrogen 0.35l) and total pressure 8kg /
cm ² . By replenishing the mixed gas of the above composition,
Polymerization was carried out for 2 hours while maintaining the total pressure at 8 kg / cm ² to obtain an ethylene polymer. The resulting ethylene polymer shown in Table 1 had a restricted amorphous portion and was an ethylene polymer having a balance between mechanical properties and moldability.

Examples 2 to 7 The same operations as in Example 1 were carried out except that the amounts of 1-butene and hydrogen in the mixed gas were changed, to obtain ethylene polymers as shown in Table 1. In Examples 3, 4, and 5, polymerization was performed without adding 1-butene. The amorphous portion of the obtained ethylene polymer was constrained, and was an ethylene polymer having a balance between mechanical properties and moldability. (Example 8) 50 parts by weight of the ethylene polymer of Example 4 and 50 parts by weight of the ethylene polymer of Example 6 were mixed using a twin screw extruder at 200 ° C. The ESCR of this ethylene polymer composition was 1000 hours, and had an excellent ESCR as compared with the composition of Comparative Example 5.

(Comparative Examples 1, 2, and 4) <Ethylene Polymer with Ziegler Catalyst> Table 1 is shown using a known Ziegler catalyst prepared from magnesium chloride hexahydrate, 2-ethylhexanol and magnesium chloride. The ethylene-1 butene copolymer of Comparative Examples 1 and 2 and the ethylene homopolymer of Comparative Example 4 were polymerized. Comparative Examples 1 and 2 of the obtained ethylene polymer
Is inferior in mechanical properties as compared with Examples 1 and 2 of the present invention. This is because the amorphous part is not sufficiently restrained. (Comparative Example 3) In Example 1, the temperature was 160 ° C and solution polymerization was carried out to obtain an ethylene polymer shown in Table 1.
Although the amorphous portion of the ethylene polymer is sufficiently constrained, the Mw / Mn of the ethylene polymer is narrow and the moldability is poor. Comparative Example 5 50 parts by weight of the ethylene polymer of Comparative Example 4 and 50 parts by weight of the ethylene polymer of Example 6 were mixed using a twin screw extruder at 200 ° C. The ESCR of this ethylene polymer composition was 500 hours. This is Comparative Example 4.
This is because the amorphous part of the ethylene polymer of Example 4 is not sufficiently restricted as compared with the ethylene polymer of Example 4.

[0044]

[Table 1]

[0045]

The ethylene polymer of the present invention is excellent in moldability, the amorphous part is sufficiently constrained, and particularly excellent in ductile fracture. This ethylene polymer can be applied to films, blows, pipes, etc., and is particularly suitable for pipes in which ductile fracture is a problem. Also, the bimodal composition of the present invention in which the low molecular weight ethylene polymer and the high molecular weight ethylene polymer are combined has excellent physical properties.

Claims (8)

[Claims] 1. An ethylene homopolymer or a copolymer of ethylene and an α-olefin having 3 to 20 carbon atoms,
(A) a melt index at a load of 2.16 kg at 190 ° C. of 0.001 to 1000 g / 10 minutes;
A density of 0.90 g / cm ^{3 to} 0.985 g / cm ³ ,
(C) the molecular weight distribution measured by gel permeation chromatography is 3 to 7, and (D) the spin-spin relaxation time T of the crystal part determined by ¹ H pulse NMR at 40 ° C.
_2c (microsecond) and the spin-spin relaxation time T of the amorphous part
An ethylene polymer, wherein the ratio T _2a / T _2c to _2a (microseconds) is 7.2 or less. 2. Spin-spin relaxation time T _2c (microsecond) of a crystal part determined by ¹ H pulse NMR at 40 ° C.
And amorphous part spin-spin relaxation time T _2a (microseconds)
2. The ethylene polymer according to claim 1, wherein the ratio T _2a / T _2c is 6.5 or less. 3. The ethylene polymer according to claim 1, having a melt index at 190 ° C. under a load of 2.16 kg of 0.05 to 600 g / 10 min. 4. A density of 0.915 g / cm ^{3 to} 0.980.
Ethylene polymer according to any one of claims 1 to 3 in the range of g / cm ^3. 5. The ethylene according to claim 1, wherein a value obtained by dividing a melt index at a load of 21.6 kg at 190 ° C. by a melt index at a load of 2.16 kg at 190 ° C. is 19 to 40. Polymer. 6. The ethylene polymer according to claim 1, wherein the spin-spin relaxation time T _2c of the crystal part is 10 microseconds or less. 7. The melt index at a load of 2.16 kg at 190 ° C. is Xg / 10 minutes and the density is Yg / cm ^3.
Ethylene homopolymer and 2.16 at 190 ° C.
In an ethylene copolymer having a melt index under a kg load of Xcg / 10 minutes and a density of Ycg / cm ³ , the peak frequency ν (cm ⁻ cm) of an acoustic band in the primary long axis direction determined by laser Raman spectroscopy. The ethylene polymer according to any one of claims 1 to 6, wherein ¹ ) is in a range represented by the following formula. 0.0768 × LogX + 30 (Y−Yc) +10.3 (cm ⁻¹ ) <ν (cm
^-1 ) [However, in the case of ethylene homopolymer, 0.0768 x LogX +
10.3 (cm ^-1 ) <ν (cm ^-1 )] 8. At least (a) a carrier substance, (a) an organic aluminum compound, (c) a borate compound having active hydrogen, (d) a titanium compound η-bonded to a cyclopentadienyl or substituted cyclopentadienyl group, The ethylene polymer according to any one of claims 1 to 7, which is obtained by using a supported catalyst adjusted from the above, and obtaining ethylene alone or copolymerizing ethylene and an α-olefin having 3 to 20 carbon atoms in a slurry state.