CN101407562B - Catalyst for broad/bimodal molecular weight distribution polyolefin and preparation method thereof - Google Patents

Abstract

The invention disclose a catalyst with wide/bimodality molecular weight distribution polyolefin and a preparation method thereof, belonging the field of catalysts, wherein the major catalyst comprises the following constituents: an inorganic substance carrier after activation treatment by an alkyl metal compound, the carrier loads at least one type of dialkyl magnesium compound, at least one type of polyfunctional compound and at least one type of titanium compound. The proportion among each constituent is calculated by each mol alkyl metal compound: 0.05-10 mol of carrier, 0.05-30mol of dialkyl magnesium compound, and 0.1-50mol of polyfunctional compound; and the amount of cocatalyst is calculated by titanium in the major catalyst being 1mol, and the cocatalyst is 10-300mol. The invention also discloses a preparation method of the catalyst, the catalyst is high in activity and the preparation method is simple, low requirement on equipment, little pollution to the environment, and has good hydrogen harmonic copolymerization performance. The catalyst is applicable to slurry process and gas phase polymerization technology and single reactor technology.

Description

Catalyst for broad/bimodal molecular weight distribution polyolefin and preparation method thereof

technical field

The invention relates to a Ziegle-Natta supported catalyst for homopolymerization or copolymerization of olefins, especially ethylene, and a preparation method for synthesizing polyolefin resin with wide molecular weight distribution by using the catalyst.

Background technique

At present, my country's ethylene output is large, which provides a reliable raw material guarantee for the polyethylene industry. However, due to the increasing shortage of petroleum resources in my country and the world, and the post-petroleum era is approaching, it is urgent to develop resin products with less consumption, easy processing and no loss of original performance. Broad molecular weight distribution/multimodal polyethylene can thin the film, and can also further thin the wall of blow molded bottles, extruded pipes and profiles, reduce the amount of resin used in a single product, and have better environmental stress cracking resistance; The wide molecular weight distribution/multimodal polyethylene resin has good recyclability, and the mechanical properties of the second-use resin are better than the first-time unimodal polyethylene resin; the wide molecular weight distribution/multimodal polyethylene resin basically does not lose the physical properties of PE Under certain conditions, the processing performance of PE can be significantly improved. Therefore, it is of great practical significance to develop broad molecular weight distribution/multimodal polyethylene resin products.

At present, the methods for preparing bimodal polyethylene reported in the literature mainly include: simple melt blending method, segmented reaction method and one-stage reaction method. Since the one-stage reaction method can effectively adjust the molecular weight and molecular weight distribution of the polymerization product only by adjusting the type and distribution of the active centers in the catalytic system, and the quality of the polymerization product is stable and the investment is low, so the research in this area is increasingly attracting attention from the business community and academic attention. At present, the methods for preparing polyethylene with a wide distribution in the amount by "one-stage method" mainly include "composite main catalyst method" and "composite support method". However, there are few reports on the preparation of broad-peak polyethylene by a single carrier. In the existing high-efficiency Mg-Ti catalytic system, the recent development is to add electron donor compounds during the preparation of catalyst components. Experiments have proved that the introduction of electron donor compounds can improve the polymerization activity of the catalyst and the hydrogen tuning performance of the catalyst.

CN 1158136A discloses the use of long carbon chain aliphatic alcohol compounds with α-branches in the process of catalyst composition preparation. The introduction of such compounds improves the polymerization activity and hydrogen adjustment performance of the catalyst. However, the viscosity of this system is relatively high (it can be seen from the examples that the catalyst component with good fluidity is obtained), which brings difficulties to the preparation process.

Contents of the invention

The purpose of the present invention is to provide a catalyst suitable for preparing polyethylene resin with wide molecular weight distribution or bimodal distribution by olefin polymerization in a single reactor. Provided is a preparation method for preparing polyethylene resin with wide molecular weight distribution or bimodal distribution with a single carrier catalyst. The catalyst has high activity, simple preparation method, low requirement on equipment and little environmental pollution.

The present invention provides a kind of catalyst that is used for the wide/bimodal molecular weight distribution polyolefin of ethylene polymerization; Described catalyst is made up of procatalyst and cocatalyst, is characterized in that:

The main catalyst includes the following components: an inorganic oxide carrier (a) after activation treatment of an alkyl metal compound (b) with the general formula MeR ¹ R ² R ³ , wherein R ¹ , R ² , and R ³ are C ₁ ~ C ₃₀ hydrocarbon groups; at least one dihydrocarbyl magnesium compound (c) with the general formula MgR ⁴ R ⁵ is supported on the carrier, where R ⁴ and R ⁵ are C ₁ ~ C ₂₀ hydrocarbon groups,

The load has at least one general formula of

的多官能团化合物(d)，

The polyfunctional compound (d),

Among the six functional groups of R6, R7, R8, R9, R10 and R11 in the general formula (d), at least one of the functional groups is a halogen group, and the halogen includes: F, Cl, Br or I. When the halogen group is more than two Each of them can be the same or different halogen groups; wherein at least one functional group is a hydroxyl group, an acyl group, an amine group or an ester group, which can be the same or different; wherein at least one group is a C1-C20 hydrocarbon group, an aromatic group , a heteroatom-containing substituent group and derivatives substituted by the halogen group or functional group.

Loading at least one titanium compound (e) with the general formula Ti(OR ¹² ) _4-m X _m , R ¹² is an aliphatic hydrocarbon group, aromatic hydrocarbon group, COR` or COOR` of C ₁ to C ₂₀ , wherein R` is a C ₁ ~C ₁₀ aliphatic or aromatic group;

The ratio between the components is based on the metal alkyl compound of MeR ¹ R ² R ³ per mole: the carrier is 0.05-10 mol, the dihydrocarbyl magnesium compound MgR ⁴ R ⁵ is 0.05-30 mol, and the multifunctional compound is 0.05-10 mol. Titanium compound: 0.1-50mol;

The general formula of the co-catalyst is AlR _n X _3-n , where R is an aliphatic hydrocarbon group of C ₁ to C ₁₅ , X is a halogen atom, and n is a positive integer from 0 to 3; The content is based on 1 mol, and the co-catalyst is 10-300 mol.

Procatalyst preparation comprises the following steps:

(1) dissolving or dispersing the inorganic oxide carrier after the activation treatment of the metal alkyl compound with the general formula MeR ¹ R ² R ³ in an inert solvent;

(2) adding dihydrocarbyl magnesium compound MgR ⁴ R ⁵ ;

惰性溶剂中溶解或分散后的产物；(3) Add the multifunctional compound

products dissolved or dispersed in inert solvents;

(4) Add titanium compound Ti(OR ¹² ) _4-m X _m , react at -50°C to 150°C for 0.5 to 24 hours, remove unreacted matter and solvent, and wash with toluene and hexane to obtain the main catalyst.

The carrier used in the present invention is mainly used to load the active ingredient. The carrier (a) is selected from silica, silicon carbide, magnesium dihalide, alumina, aluminum halide, silica alumina, magnesia, titania, vanadium oxide, activated carbon, diatomaceous earth, chromium oxide, zirconia and the like. Silica, magnesium chloride are preferred.

The metal alkyl compound is represented by the general formula (b) MeR ¹ R ² R ³ , wherein R ¹ , R ² , and R ³ are the same or different C ₁ -C ₃₀ hydrocarbon groups, and C ₁ -C ₃₀ Straight chain, branched chain or cyclic alkyl is preferred, Me is an element of group IIIA in the periodic table of elements, aluminum is preferred, typical compounds such as trimethylaluminum, triethylaluminum, tripropylaluminum, triisobutyl triethylaluminum, tri-n-hexylaluminum, trioctylaluminum, etc., among which triethylaluminum and triisobutylaluminum are preferred.

The dihydrocarbyl magnesium compound is represented by the general formula (c) MgR ⁴ R ⁵ , wherein R ⁴ and R ⁵ are the same or different C ₁ -C ₂₀ hydrocarbon groups, preferably the same or different C ₂ -C ₁₅ Alkyl groups, such as: ethyl, propyl, butyl, pentyl, hexyl, octyl, etc. Specific examples include, but are not limited to: di-n-butyl magnesium, n-butyl sec-butyl magnesium, diisopropyl magnesium, di-n-hexyl magnesium, isopropyl n-butyl magnesium, ethyl n-hexyl magnesium, ethyl n-butyl Magnesium, di-n-octyl magnesium, butyl octyl magnesium, the suitable dihydrocarbyl magnesium compound in the reaction is preferably dibutyl magnesium, butyl ethyl magnesium or butyl octyl magnesium, etc.

所示。Described polyfunctional compound such as general formula (d)

shown.

Among the six functional groups of R6, R7, R8, R9, R10 and R11 in the general formula (d), at least one of the functional groups is a halogen group, and the halogen includes: F, Cl, Br or I. When the halogen group is more than two When two, it can be the same or different halogen groups; at least one of the functional groups is a functional group such as hydroxyl, acyl, amine or ester group, and when there are more than two functional groups, it can be the same or different functional groups group; the remaining groups are C ₁ -C ₂₀ hydrocarbon groups, aryl groups, substituent groups containing heteroatoms and derivatives substituted by said halogen groups or functional groups. Specific examples of multifunctional compounds include, but are not limited to:

preferred

The titanium compound is such as the general formula (e) Ti(OR ¹² ) _4-m X _m , wherein X is a halogen atom, m is an integer from 0 to 4, and R ¹² is an aliphatic hydrocarbon group of C ₁ to C ₂₀ , or An aromatic hydrocarbon group or COR', or COOR'(R' is an aliphatic group or an aromatic group having C ₁ to C ₁₀ ), and each R ¹² may be the same or different. ^R is preferably: methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, isobutyl, tert-butyl, isopentyl, tert-amyl, 2-Ethylhexyl, phenyl, naphthyl, o-methylphenyl, m-methylphenyl, p-methylphenyl, o-sulfophenyl, formyl, acetyl, benzoyl etc. Specifically, titanium tetrachloride, titanium tetrabromide, titanium tetraiodide, tetrabutoxytitanium, tetraethoxytitanium, monochlorotriethoxytitanium, dichlorodiethoxytitanium, trichloroethyl Titanium oxide, n-butyl titanate, isopropyl titanate, methoxytitanium trichloride, dibutoxytitanium dichloride, tributoxytitanium chloride, tetraphenoxytitanium, monochlorotrichloride One of phenoxytitanium, dichlorodiphenoxytitanium, trichlorophenoxytitanium or their mixture, the titanium compound should be completely soluble in non-polar solvents at the application temperature A liquid compound, preferably titanium tetrachloride.

The inert solvent described in the main catalyst component of the present invention can adopt hexane, heptane, octane, hexane, decane, undecane, dodecane, benzene, toluene, xylene, tetrahydrofuran, 1,2-bis Ethyl chloride, chlorobenzene, 1,4-dioxane and other hydrocarbons or halogenated hydrocarbon compounds, the above inert solvents can be used alone or in combination.

In the preparation process of the main catalyst component of the present invention, the ratio between the components is calculated per mole of the compound of general formula (b): the carrier is 0.05 to 10 mol, preferably 0.1 to 5 mol; the dihydrocarbyl magnesium compound MgR ⁴ R ⁵ (c) is 0.05-30 mol, preferably 0.1-10 mol; multifunctional compound (d) is 0.05-10 mol, preferably 0.1-5 mol; titanium compound such as general formula (e): 0.1-50 mol, preferably 1-30 mol.

The reaction process in the present invention is generally at -50°C to 150°C. The reaction time can also be changed in a wide range, generally 0.5 to 24 hours, and the components should be reacted for a long enough time at the desired reaction temperature. In order to further improve the particle shape of the catalyst and the bulk density of the polymerization product, a slight vacuum, elevated temperature or nitrogen purging can be used in the intermediate steps.

The general formula of the cocatalyst of the present invention is AlR _n X _3-n , where R is hydrogen or a hydrocarbon group with 1 to 20 carbon atoms, X is a halogen, and n is a number of 0<n≤3; more typical Compounds such as: trimethylaluminum, triethylaluminum, tripropylaluminum, triisobutylaluminum, tri-n-hexylaluminum, tri-tert-butylaluminum, trioctylaluminum, monochlorodiethylaluminum, dichloroethylaluminum triethylaluminum, sesquiethylaluminum chloride, etc., among which triethylaluminum and triisobutylaluminum are preferred; they can be used alone or in combination.

In the present invention, the ratio of the co-catalyst to the catalyst component is based on the titanium content (1 mol) in the obtained catalyst component, and the co-catalyst is 10-300 mol, preferably 50-200 mol.

The catalyst involved in the present invention is suitable for the homopolymerization of ethylene or the copolymerization of ethylene and α-olefin, wherein α-olefin is preferably propylene, 1-butene, 1-hexene, 1-octene, 4-methyl-1- Pentene, 1,3-dibutene, isoprene, styrene, etc.

Homopolymerization of ethylene or copolymerization of ethylene with α-olefins can be carried out using the following reaction conditions:

Polymerization temperature: 10-130°C, preferably 60-100°C

Polymerization pressure: 0.1-10.0MPa, preferably 0.1-2.0MPa

The invention provides a catalyst for preparing polyolefin with wide molecular weight distribution. The catalyst has high activity, simple preparation method, low equipment requirement, little environmental pollution, and good hydrogen blending and copolymerization performance. The catalyst is suitable for slurry and gas phase polymerization processes. Suitable for single reactor process.

Detailed ways

The specific embodiments are preferred examples of the present invention, but are not limited to the following examples in practical application.

Determination of the Ti content of the catalyst: weigh 0.5 g of the catalyst and dissolve it in concentrated sulfuric acid, and measure its content with a spectrophotometer.

Relative molecular mass and distribution determination of PE: The weight average relative molecular mass (M _w ), number average relative molecular mass (M _n ) and Its distribution (M _w /M _n ), the solvent is 1,2,4-trichlorobenzene, the mass concentration of the sample is 1mg/mL, the solution flow rate is 1.0mL/min, and the test temperature is 150°C.

Determination of polymer melt index (MI): measured by ASTM D1238-99.

Example 1

(1) Preparation of catalyst components: In a reactor fully replaced by nitrogen, add 1 g of silicon dioxide, 30 ml of freshly distilled hexane, and 0.6 ml of AlEt ₃ (2.0M), heat up to 50 ° C for 1 h, Add 4.8ml of dibutylmagnesium (prepared to a heptane solution with a concentration of 1.0M), 20ml of tetrahydrofuran, and 0.646g of 2,2'-methylenebis(4-chlorophenol), heat up to 60°C for 1 hour, and cool down to - Add TiCl ₄ dropwise at 25°C to make 1.3ml, raise the temperature to 70°C and react for 2 hours, stop stirring, let it stand still, remove the supernatant, wash twice with toluene and hexane, and blow dry with nitrogen to obtain a liquid with good fluidity and particle size distribution Narrow solid catalyst component.

(2) Ethylene polymerization

In a 0.5-liter stainless steel autoclave, after being fully replaced by nitrogen, 20 mg of the above-mentioned synthesized catalyst component (1), 200 ml of dehydrated hexane, and _0.46 ml (2 mmol/ml) of AlEt solution were added to the autoclave successively, and the temperature was raised to 80 ° C. Charge hydrogen 0.28MPa, fill ethylene 0.45MPa, and react at constant pressure and temperature for 2 hours. The experimental results are shown in Table 1.

Example 2

(1) Preparation of catalyst components: In a reactor fully replaced by nitrogen, sequentially add 1 g of silicon dioxide, 30 ml of freshly distilled hexane, and 0.1 ml of AlEt ₃ (2.0 M), heat up to 50 ° C for 1 h, Add 0.1ml of a heptane solution (1.0M) of dibutylmagnesium dropwise, 20ml of tetrahydrofuran, 0.03g of 2,2'-methylenebis(4-chlorophenol), heat up to 60°C for 1 hour, then cool down to -25°C Add TiCl ₄ dropwise to make 0.13ml, raise the temperature to 70°C and react for 2h, stop stirring, let it stand still, remove the supernatant, wash twice with toluene and hexane, and blow dry with nitrogen to obtain a compound with good fluidity and narrow particle size distribution. solid catalyst components.

Just change the amount of _AlEt3 solution into 0.32ml in the ethylene polymerization, other conditions are the same as embodiment 1

Example 3

(1) Preparation of catalyst components: In a reactor fully replaced by nitrogen, sequentially add 1 g of silicon dioxide, 30 ml of freshly distilled hexane, and 6 ml of AlEt ₃ (2.0M), heat up to 50°C for 1 h, drop Add 12ml of heptane solution (1.0M) of dibutylmagnesium, 50ml of tetrahydrofuran, 0.03g of 2,2'-methylene bis(4-chlorophenol), heat up to 60°C for 1 hour, cool down to -25°C and add dropwise TiCl ₄ was 4.0ml, heated up to 70°C and reacted for 2 hours, stopped stirring, stood still, pumped off the supernatant, washed twice with toluene and hexane, and dried with nitrogen to obtain a solid catalyst with good fluidity and narrow particle size distribution components.

Just change the amount of _AlEt3 solution into 0.43ml in ethylene polymerization, other conditions are the same as embodiment 1

Example 4

Except changing 2,2'-methylenebis(4-chlorophenol) in the catalyst preparation process into 1,4-dichloro-2,5-dihydroxybenzene 0.430g, other is the same as embodiment 1;

Just change the amount of _AlEt3 solution into 0.41ml in the ethylene polymerization, other conditions are the same as embodiment 1.

Example 5

Except that 2,2'-methylenebis(4-chlorophenol) in the catalyst preparation process was changed into 2-amine-4,6-dichloro-5-cresol 0.461g, others were the same as in Example 1;

Just change the amount of _AlEt3 solution into 0.37ml in the ethylene polymerization, other conditions are the same as embodiment 1.

Example 6

Except changing 2,2'-methylenebis(4-chlorophenol) in the catalyst preparation process into 4-amine-2,6-dichlorocresol 0.427g, other is the same as embodiment 1;

Just change the amount of _AlEt3 solution into 0.44ml in the ethylene polymerization, other conditions are the same as embodiment 1.

Example 7

Except changing the _TiCl in the catalyst preparation process to 0.7ml, other is the same as Example 1;

Just change the amount of _AlEt3 solution into 0.41ml in the ethylene polymerization, other conditions are the same as embodiment 1.

Example 8

Except changing the _TiCl in the catalyst preparation process to 2.6ml, other is the same as Example 1;

Just change the amount of _AlEt3 solution into 0.46ml in the ethylene polymerization, other conditions are the same as embodiment 1.

Example 9

Except not adding 2,2'-methylene bis(4-chlorophenol) in the catalyst preparation process, other are identical with embodiment 1;

Just change the amount of _AlEt3 solution into 0.29ml in the ethylene polymerization, other conditions are the same as embodiment 1.

Example 10

Preparation of the catalyst component: in a reactor fully replaced by nitrogen, add 1g of magnesium dichloride successively, newly distilled THF 30ml, add dropwise 2.8ml of a heptane solution (1.0M) of dibutylmagnesium, 2,2'- Methylbis(4-chlorophenol) 0.33g, heated up to 60°C and reacted for 1h, cooled to -25°C and added 8ml of TiCl ₄ dropwise, raised to 70°C and reacted for 2h, added dropwise 40ml of freshly distilled hexane, stopped stirring, and place, remove the supernatant, wash with toluene and hexane twice, and blow dry with nitrogen to obtain a solid catalyst component with good fluidity and narrow particle size distribution.

Just change the amount of _AlEt3 solution into 1.48ml in the ethylene polymerization, other conditions are the same as embodiment 1.

Example 11

Except that 2,2'-methylenebis(4-chlorophenol) in the catalyst preparation process was changed into 1,4-dichloro-2,5-dihydroxybenzene 0.28g, others were the same as in Example 10;

Just change the amount of _AlEt3 solution into 1.31ml in the ethylene polymerization, other conditions are the same as embodiment 1.

Example 12

Except that 2,2'-methylenebis(4-chlorophenol) in the catalyst preparation process was changed into 2-amine-4,6-dichloro-5-cresol 0.31g, others were the same as in Example 10;

Just change the amount of _AlEt3 solution into 1.21ml in the ethylene polymerization, other conditions are the same as embodiment 1.

Example 13

Except that 2,2'-methylenebis(4-chlorophenol) in the catalyst preparation process was changed into 4-amine-2,6-dichlorocresol 0.30g, others were the same as in Example 10;

Just change the amount of _AlEt3 solution into 1.27ml in the ethylene polymerization, other conditions are the same as embodiment 1.

Example 14

Except that the _TiCl in the catalyst preparation process was changed to 2.0ml of titanium tetrabromide, the others were the same as in Example 1.

Just change the amount of _AlEt3 solution into 0.41ml in the ethylene polymerization, other conditions are the same as embodiment 1.

Example 15

Except changing TiCl4 in the catalyst preparation process into tetraethoxytitanium 2.3, other is the same as embodiment 1.

Just change the amount of _AlEt3 solution into 0.29ml in the ethylene polymerization, other conditions are the same as embodiment 1.

Example of copolymerization

Example 16

The preparation of catalyst is with embodiment 1;

The catalyst evaluation conditions were only that after adding the catalyst, 15 ml of 1-hexene was added to carry out copolymerization of ethylene and hexene. Others are the same as in Example 1. The experimental results are shown in Table 1.

Example 17

The preparation of catalyst is with embodiment 3;

The catalyst evaluation conditions were only that after adding the catalyst, 15 ml of 1-hexene was added to carry out copolymerization of ethylene and hexene. Others are identical with embodiment 3. The experimental results are shown in Table 1.

Example 18

The preparation of catalyst is with embodiment 4;

The catalyst evaluation conditions were only that after adding the catalyst, 15 ml of 1-hexene was added to carry out copolymerization of ethylene and hexene. Others are the same as in Example 4. The experimental results are shown in Table 1.

Example 19

The preparation of catalyst is with embodiment 5;

The catalyst evaluation conditions were only that after adding the catalyst, 15 ml of 1-hexene was added to carry out copolymerization of ethylene and hexene. Others are the same as in Example 5. The experimental results are shown in Table 1.

Example 20

The preparation of catalyst is with embodiment 6;

The catalyst evaluation conditions were only that after adding the catalyst, 15 ml of 1-hexene was added to carry out copolymerization of ethylene and hexene. Others are the same as in Example 6. The experimental results are shown in Table 1.

Example 21

The preparation of catalyst is with embodiment 7;

The catalyst evaluation conditions were only that after adding the catalyst, 15 ml of 1-hexene was added to carry out copolymerization of ethylene and hexene. Others are the same as in Example 7. The experimental results are shown in Table 1.

Example 22

The preparation of catalyst is with embodiment 8;

The catalyst evaluation conditions were only that after adding the catalyst, 15 ml of 1-hexene was added to carry out copolymerization of ethylene and hexene. Others are the same as in Example 8. The experimental results are shown in Table 1.

Example 23

The preparation of catalyst is with embodiment 9;

The catalyst evaluation conditions were only that after adding the catalyst, 15 ml of 1-hexene was added to carry out copolymerization of ethylene and hexene. Others are the same as in Example 9. The experimental results are shown in Table 1.

Example 24

The preparation of catalyst is with embodiment 10;

The catalyst evaluation conditions were only that after adding the catalyst, 15 ml of 1-hexene was added to carry out copolymerization of ethylene and hexene. Others are the same as in Example 10. The experimental results are shown in Table 1.

Example 25

The preparation of catalyst is with embodiment 11;

The catalyst evaluation conditions were only that after adding the catalyst, 15 ml of 1-hexene was added to carry out copolymerization of ethylene and hexene. Others are the same as in Example 11. The experimental results are shown in Table 1.

Example 26

The preparation of catalyst is with embodiment 12;

The catalyst evaluation conditions were only that after adding the catalyst, 15 ml of 1-hexene was added to carry out copolymerization of ethylene and hexene. Others are the same as in Example 12. The experimental results are shown in Table 1.

Example 27

The preparation of catalyst is with embodiment 13;

The catalyst evaluation conditions were only that after adding the catalyst, 15 ml of 1-hexene was added to carry out copolymerization of ethylene and hexene. Others are the same as in Example 13. The experimental results are shown in Table 1.

Example 28

The preparation of catalyst is with embodiment 14;

The catalyst evaluation conditions were only that after adding the catalyst, 15 ml of 1-hexene was added to carry out copolymerization of ethylene and hexene. Others are the same as in Example 13. The experimental results are shown in Table 1.

Example 29

The preparation of catalyst is with embodiment 15;

The catalyst evaluation conditions were only that after adding the catalyst, 15 ml of 1-hexene was added to carry out copolymerization of ethylene and hexene. Others are the same as in Example 13. The experimental results are shown in Table 1.

Table 1

Ti content (mass%) Catalytic efficiency (KgPE/gcat) MWD Bulk density (g/ml) MI _2.16 (g/10min) Example 1 2.21 3.6 13.7 0.39 0.45 Example 2 1.53 1.0 8.7 0.37 0.33 Example 3 2.07 3.4 13.2 0.38 0.42 Example 4 1.94 3.0 11.1 0.37 0.37 Example 5 1.76 2.1 9.9 0.38 0.33 Example 6 2.10 2.4 12.3 0.38 0.41 Example 7 1.98 2.7 11.4 0.38 0.40

Example 8 2.18 3.6 13.6 0.39 0.44 Example 9 1.41 1.9 3.7 0.37 0.30 Example 10 7.11 44.3 27.5 0.32 0.38 Example 11 6.32 42.2 23.7 0.32 0.31 Example 12 5.83 39.9 24.0 0.30 0.29 Example 13 6.14 42.2 25.2 0.31 0.36 Example 14 1.50 2.3 10.7 0.38 0.34 Example 15 1.42 2.1 9.8 0.39 0.37 Example 16 2.21 3.9 14.4 0.38 0.72 Example 17 2.07 3.6 14.2 0.38 0.68 Example 18 1.94 3.5 13.4 0.39 0.65 Example 19 1.76 2.5 10.7 0.39 0.59 Example 20 2.10 3.4 12.9 0.38 0.66 Example 21 1.98 2.4 12.6 0.39 0.61 Example 22 2.18 3.3 14.1 0.39 0.67 Example 23 1.41 1.9 4.3 0.38 0.53 Example 24 7.11 44.0 28.1 0.32 0.73 Example 25 6.32 43.4 24.4 0.31 0.69 Example 26 5.83 41.1 24.8 0.30 0.66 Example 27 6.14 43.3 26.6 0.32 0.71 Example 28 1.50 2.7 11.7 0.39 0.67 Example 29 1.42 2.4 10.3 0.39 0.61

Claims (2)

1. a kind of catalyst of broad/bimodal molecular weight distribution polyolefin, described catalyst is made up of procatalyst and cocatalyst, it is characterized in that: The main catalyst includes the following components: an inorganic carrier after activation treatment of an alkyl metal compound with the general formula MeR ¹ R ² R ³ , where R ¹ , R ² , and R ³ are C ₁ -C ₃₀ direct chain, branched or cyclic alkyl group, Me is a group IIIA element in the periodic table of elements; the inorganic carrier is selected from silicon dioxide, silicon carbide, magnesium dihalide, aluminum oxide, aluminum halide, silicon aluminum oxide, magnesium oxide, oxide Vanadium, activated carbon, chromium or zirconia; Loading at least one dihydrocarbyl magnesium compound with the general formula MgR ⁴ R ⁵ on the support, wherein R ⁴ and R ⁵ are C ₁ -C ₂₀ hydrocarbon groups; The load has at least one general formula of

multifunctional compounds, Among the six functional groups of R6, R7, R8, R9, R10 and R11 in the formula, at least one of them is a halogen group, at least one but not including one is a functional group, and the functional group is a hydroxyl group, an acyl group, an amino group or ester group, the remaining groups are C1-C20 hydrocarbon groups or aromatic groups; and at least one titanium compound with the general formula Ti(OR ¹² ) _4-m X _m is supported, where X is a halogen atom and m is 0 to 4 is an integer, R ¹² is an aliphatic or aromatic hydrocarbon group with C ₁ to C ₂₀ , COR` or COOR`, wherein R` is an aliphatic or aromatic group with C ₁ to C ₁₀ ; The ratio between the components is based on the metal alkyl compound of MeR ¹ R ² R ³ per mole: 0.05-10 mol for the inorganic carrier, 0.05-30 mol for the dihydrocarbyl magnesium compound MgR ⁴ R ⁵ , and 0.05-30 mol for the multifunctional compound 10mol, titanium compound: 0.1～50mol; The general formula of the co-catalyst is AlR _n X _3-n , where R is an aliphatic hydrocarbon group of C ₁ to C ₁₅ , X is a halogen atom, and n is a positive integer from 0 to 3; The content is based on 1 mol, and the co-catalyst is 10-300 mol. 2. according to the preparation method of the catalyst of the described wide/bimodal molecular weight distribution polyolefin of claim 1, it is characterized in that, main catalyst preparation comprises the following steps: (1) dissolving or dispersing the activated inorganic carrier in an inert solvent; (2) adding dihydrocarbyl magnesium compound MgR ⁴ R ⁵ ; (3) Add the multifunctional compound

Products dissolved or dispersed in inert solvents; (4) Add titanium compound Ti(OR ¹² ) _4-m X _m , where X is a halogen atom, m is an integer from 0 to 4, react at -50°C to 150°C for 0.5 to 24 hours, remove unreacted substances and solvent, and washed with toluene and hexane to obtain the main catalyst.