CN113214416B - Combined external electron donor, olefin polymerization catalyst and application thereof, and polyolefin and preparation method thereof - Google Patents

Abstract

第二外给电子体化合物具有式II所示的结构：

第一外给电子体化合物和第二外给电子体化合物的摩尔比为10‑100：1。采用本发明的外给电子体组合物，将第一外给电子体化合物和第二外给电子体化合物组合使用，得到的烯烃聚合催化剂用于烯烃聚合反应时，能够获得橡胶含量高的抗冲聚丙烯，且该聚丙烯还具有较高的熔融指数，特别是橡胶含量为35‑45％，熔融指数为30‑80g/10min的抗冲聚丙烯。The invention relates to the field of olefin polymerization, and discloses an external electron donor composition, an olefin polymerization catalyst and its application, as well as a polyolefin and a preparation method thereof. The external electron donor composition contains a first external electron donor compound and a second external electron donor compound, wherein the first external electron donor compound is selected from at least one of compounds having the structure shown in formula I:

The second external electron donor compound has the structure shown in formula II:

The molar ratio of the first external electron donor compound and the second external electron donor compound is 10-100:1. By using the external electron donor composition of the present invention, the first external electron donor compound and the second external electron donor compound are used in combination, and when the obtained olefin polymerization catalyst is used in the olefin polymerization reaction, impact resistance with high rubber content can be obtained Polypropylene, and the polypropylene also has a high melt index, especially impact polypropylene with a rubber content of 35-45% and a melt index of 30-80g/10min.

Description

Combined external electron donor, olefin polymerization catalyst and application thereof, and polyolefin and preparation method thereof

technical field

The invention relates to the field of olefin polymerization, in particular to a combined external electron donor, an olefin polymerization catalyst and application thereof, as well as a polyolefin and a preparation method thereof.

Background technique

As one of the five major synthetic resins in the world, polypropylene has the characteristics of low price, good processing performance, low density, chemical corrosion resistance and excellent mechanical properties, and is widely used. However, the impact resistance (toughness) of homopolypropylene is poor at low temperature, which seriously limits its further application in various fields.

At present, there are two main methods of polypropylene toughening modification: mechanical blending with elastomer and copolymerization with a certain amount of ethylene to form impact copolymer polypropylene. However, due to the poor compatibility between polypropylene and elastomer, mechanical blending is difficult to make the elastomer evenly distributed in the polypropylene matrix, the size of the dispersed phase is large, and the toughening effect of the material is not ideal. Copolymerization with ethylene to produce impact polypropylene is an efficient and economical practice. Impact polypropylene is a heterophasic mixture of polypropylene produced from (at least) two reactors connected in series. The first reactor produces a homogeneous mixture of propylene. The polymer is transported to the second reactor, and propylene and ethylene or other olefin monomers are passed into the second reactor to carry out the copolymerization reaction, and the ethylene-propylene random copolymer is mainly formed in the pores of the propylene homopolymer. material (rubber phase). The final impact polypropylene has a good balance of rigidity and toughness, and has a wide range of applications.

The formation of the rubber phase can improve the impact properties of impact polypropylene, but it also greatly reduces the melt index of impact polypropylene. Therefore, the production of impact polypropylene with high melt index and high rubber content puts forward higher requirements for polypropylene catalysts. On the basis of maintaining the high activity and copolymerization ability of the catalyst, it is necessary to improve the hydrogen adjustment sensitivity of the catalyst as much as possible. Orientation ability and particle morphology.

SUMMARY OF THE INVENTION

The purpose of the present invention is to overcome the problem that the impact-resistant polypropylene in the prior art cannot have both high rubber content and high melt index, and provides a combined external electron donor, an olefin polymerization catalyst and its application, and a polyolefin and its preparation method. .

In order to achieve the above object, a first aspect of the present invention provides an external electron donor composition, the external electron donor composition contains a first external electron donor compound and a second external electron donor compound, wherein the first external electron donor compound An external electron donor compound is selected from at least one of the compounds having the structure shown in formula I:

In formula I, R ¹ and R ² are each independently selected from any one of C ₁ -C ₁₀ alkane, C ₃ -C ₁₂ cycloalkyl and C ₆ -C ₂₀ aryl;

R ³ , R ⁴ , R ⁵ and R ⁶ are each independently selected from hydrogen, a halogen group, a C ₁ -C ₁₀ alkane group, a C ₃ -C ₁₂ cycloalkyl group, and a C ₆ -C ₂₀ aryl group any of the

R ⁷ and R ⁸ are each independently selected from any one of C ₁ -C ₅ chain alkyl groups;

R ¹ and R ² are the same or different, R ³ , R ⁴ , R ⁵ , R ⁶ are the same or different, R ⁷ and R ⁸ are the same or different;

The second external electron donor compound has the structure shown in formula II:

The molar ratio of the first external electron donor compound and the second external electron donor compound is 10-100:1.

A second aspect of the present invention provides an olefin polymerization catalyst, the olefin polymerization catalyst comprising:

(1) a solid component, the solid component is obtained from a titanium-containing compound, a magnesium-containing compound and an internal electron donor compound through a contact reaction;

(2) organoaluminum compounds; and

(3) an external electron donor composition;

The external electron donor composition is the external electron donor composition described in the first aspect.

A third aspect of the present invention provides an application of the above-mentioned olefin polymerization catalyst in an olefin polymerization reaction.

A fourth aspect of the present invention provides a method for preparing a polyolefin, the method comprising: performing a polymerization reaction of an olefin monomer in the presence of the above-mentioned olefin polymerization catalyst under the conditions of an olefin polymerization reaction.

A fifth aspect of the present invention provides a polyolefin prepared by the method described in the fourth aspect.

Through the above technical solution, using the external electron donor composition of the present invention, the first external electron donor compound and the second external electron donor compound are used in combination, and when the obtained olefin polymerization catalyst is used in the olefin polymerization reaction, a rubber can be obtained Impact polypropylene with high content and high melt index, especially impact polypropylene with rubber content of 35-45% and melt index of 30-80g/10min.

Detailed ways

The endpoints of ranges and any values disclosed herein are not limited to the precise ranges or values, which are to be understood to encompass values proximate to those ranges or values. For ranges of values, the endpoints of each range, the endpoints of each range and the individual point values, and the individual point values can be combined with each other to yield one or more new ranges of values that Ranges should be considered as specifically disclosed herein.

In the present invention, the combined external electron donor is the external electron donor composition.

A first aspect of the present invention provides an external electron donor composition, the external electron donor composition contains a first external electron donor compound and a second external electron donor compound, wherein the first external electron donor The compound is selected from at least one of the compounds having the structure shown in formula I:

In formula I, R ¹ and R ² are each independently selected from any one of C ₁ -C ₁₀ alkane, C ₃ -C ₁₂ cycloalkyl and C ₆ -C ₂₀ aryl;

R ³ , R ⁴ , R ⁵ and R ⁶ are each independently selected from hydrogen, a halogen group, a C ₁ -C ₁₀ alkane group, a C ₃ -C ₁₂ cycloalkyl group, and a C ₆ -C ₂₀ aryl group any of the

R ⁷ and R ⁸ are each independently selected from any one of C ₁ -C ₅ chain alkyl groups;

R ¹ and R ² are the same or different, R ³ , R ⁴ , R ⁵ , R ⁶ are the same or different, R ⁷ and R ⁸ are the same or different;

The second external electron donor compound has the structure shown in formula II:

The molar ratio of the first external electron donor compound and the second external electron donor compound is 10-100:1.

In some embodiments of the present invention, part of the external electron donor compound is to complex with alkyl aluminum to reduce the reducing ability of alkyl aluminum, and the other part is to complex with the active center of Ziegler-Natta catalyst to inhibit the activity of poor tropism. center, and further improve the isotropism of the active center with high isotropism. Different electron donors and active centers of Ziegler-Natta catalysts have different effect strengths. In the external electron donor composition of the present invention, after the first external electron donor compound interacts with the catalyst active center, a highly tactical active center can be obtained, and polypropylene particles with good morphology can be obtained in the first-stage polymerization, which is helpful for High rubber content is obtained in the second stage polymerization; on the one hand, the second external electron donor compound can reduce the isotactic sequence length of polypropylene in the first stage polymerization as a low isotactic external electron donor, and at the same time reduce the isotactic sequence length as a chain transfer agent The molecular weight of the polymer obtained by the two-stage polymerization reaction, so as to achieve the effect of improving the melt index of the polymer. The above-mentioned first external electron donor compound and the second external electron donor compound are used in combination, and the combined external electron donor is used to cooperate with the Ziegler-Natta catalyst containing the diester, so that a higher rubber content can be prepared with higher catalytic activity. And polyolefins with higher melt index.

In some embodiments of the present invention, the C ₁ -C ₁₀ chain alkyl group refers to a chain alkyl group with a total number of carbon atoms ranging from 1 to 10, including straight chain and branched chain alkyl groups, for example, including but not limited to Methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, isobutyl, tert-butyl, n-pentyl, isopentyl, neopentyl, n-hexyl, isohexyl, 1- Ethylpropyl, 2-methylbutyl, 3-methylbutyl, 2,2-dimethylpropyl, etc., preferably any one of methyl, ethyl and isopropyl.

In some embodiments of the present invention, the chain alkyl group has a similar definition to the above, only the number of carbon atoms is different, and the present invention will not be described in detail hereinafter.

In some embodiments of the present invention, the C ₆ -C ₂₀ aryl group refers to an aryl group with a total of 6-20 carbon atoms, including unsubstituted aryl groups and substituted aryl groups, wherein substituted aryl groups radical groups include alkaryl (alkyl substituted aryl) and aralkyl (aryl substituted alkyl), for example, including but not limited to phenyl, 2,6-dimethylphenyl, 2 ,6-diisopropylphenyl, o-tolyl, m-tolyl, p-tolyl, o-ethylphenyl, m-ethylphenyl, p-ethylphenyl, n-propylphenyl, isopropylphenyl, n-ethylphenyl Butylphenyl, sec-butylphenyl, isobutylphenyl, tert-butylphenyl, naphthyl, anthracenyl, phenanthryl, benzyl, etc., preferably phenyl, 2,6-dimethylphenyl and 2,6-diisopropylphenyl.

In some embodiments of the present invention, the aryl group has a similar definition to the above, only the number of carbon atoms is different, and the present invention will not be described in detail hereinafter.

In some embodiments of the present invention, the C ₃ -C ₁₂ cycloalkyl group refers to a cycloalkyl group with a total of 3-12 carbon atoms, for example, including but not limited to cyclopropyl, cyclobutyl, cyclopentyl, cyclo Hexyl and the like, preferably cyclohexyl.

In some embodiments of the present invention, the cycloalkyl group has a similar definition to the above, only the number of carbon atoms is different, and the present invention will not be described in detail hereinafter.

In some embodiments of the present invention, preferably, in formula I, R ¹ and R ² are each independently selected from methyl, ethyl, isopropyl, cyclohexyl, phenyl, 2,6-dimethylphenyl and 2,6-diisopropylphenyl, preferably, R ¹ and R ² are each independently cyclohexyl.

In some embodiments of the present invention, preferably, in formula I, R ³ , R ⁴ , R ⁵ and R ⁶ are each independently selected from hydrogen, fluorine, chlorine, bromine, iodine, methyl, ethyl, isopropyl , any one of tert-butyl, isobutyl, cyclopentyl, cyclohexyl, phenyl, 2,6-dimethylphenyl and 2,6-diisopropylphenyl, more preferably, R ³ , R ⁴ and R ⁵ are each independently hydrogen, and R ⁶ is selected from any one of hydrogen, methyl, ethyl and isopropyl.

In some embodiments of the present invention, preferably, in formula I, R ⁷ and R ⁸ are each independently selected from any one of methyl, ethyl, n-propyl and isopropyl, more preferably, R ⁷ and R ⁸ are each independently methyl.

According to a preferred embodiment of the present invention, the first external electron donor compound is selected from the group consisting of the compound represented by formula I-1, the compound represented by formula I-2 and the compound represented by formula I-3 At least one of:

In some embodiments of the present invention, the molar ratio of the first external electron donor compound and the second external electron donor compound is 10-100:1. Preferably, the molar ratio of the first external electron donor compound and the second external electron donor compound is 10-80:1, more preferably 20-60:1.

In the present invention, after the first external electron donor compound interacts with the active center of the catalyst, a highly tactical active center can be obtained, and polypropylene particles with good morphology can be obtained in the first-stage polymerization, which is helpful for obtaining high-elasticity in the second-stage polymerization. Rubber content; the second external electron donor compound can reduce the isotactic sequence length of polypropylene in the first-stage polymerization as a low-isotactic external electron donor, and at the same time as a chain transfer agent to reduce the polymerization obtained by the two-stage polymerization The molecular weight of the polymer can be increased, so as to achieve the effect of increasing the melt index of the polymer. The above-mentioned first external electron donor compound and the second external electron donor compound are used in combination, and the optimum value of polymer performance can be achieved by adjusting the ratio of the two external electron donor compounds to complement each other's strengths.

In some embodiments of the present invention, the inventors found that the above-mentioned preferred first external electron donor compound is specially selected to be used in combination with the second external electron donor compound having the structure shown in formula II, and the combined external electron donor compound is used. In combination with Ziegler-Natta catalyst containing diester, it is used in the preparation of polyolefin, and the obtained olefin polymer has higher rubber content and higher melt index.

In some embodiments of the present invention, the first external electron donor compound having the structure shown in formula I can be prepared by the following method:

(1) under Grignard reaction conditions, the compound shown in formula III is first contacted with metallic magnesium in a first solvent to obtain a Grignard reagent,

(2) under substitution reaction conditions, the Grignard reagent and the silane represented by formula IV are subjected to a second contact in a second solvent to obtain the first external electron donor compound,

In formula IV, R ¹ and R ² are the same or different, each independently selected from any one of C ₁ -C ₁₀ alkane, C ₃ -C ₁₂ cycloalkyl and C ₆ -C ₂₀ aryl kind;

In formula III, R ³ , R ⁴ , R ⁵ and R ⁶ are the same or different, each independently selected from hydrogen, halogen group, C ₁ -C ₁₀ alkane, C ₃ -C ₁₂ cycloalkyl and Any one of the aryl groups of C ₆ -C ₂₀ ;

In formula III, R ⁷ is any one of C ₁ -C ₅ chain alkyl groups; X ¹ is any one of halogen atoms;

In formula IV, X ² and X ³ are the same or different, and are each independently any one of halogen atoms.

In some embodiments of the present invention, in Formula III and Formula IV, R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ and R ⁷ have the same definitions as in Formula I.

In some embodiments of the present invention, in formula III, X ¹ is any one of halogen atoms, and specific examples of the halogen atoms may include but are not limited to: fluorine, chlorine, bromine and iodine. Preferably, X ¹ is bromine.

In some embodiments of the present invention, in formula IV, X ² and X ³ are the same or different, and are each independently any one of halogen atoms. Specific examples of the halogen atoms may include but are not limited to: fluorine, chlorine, bromine and iodine. Preferably, X ² and X ³ are both chlorine.

In some embodiments of the present invention, preferably, the compound represented by formula III is selected from o-bromoanisole, 1-bromo-2-methoxy-3-methylbenzene and 1-bromo-2-methoxy- Any of 3-isopropylbenzene.

In some embodiments of the present invention, preferably, the silane represented by formula IV is dicyclohexyldichlorosilane.

In some embodiments of the present invention, preferably, the molar ratio of the compound represented by the formula III to the metal magnesium can be 1:1-2, and the molar ratio of the compound represented by the formula III to the silane represented by the formula IV can be 1: 0.9-1.2.

In some embodiments of the present invention, preferably, in step (1), the temperature of the first contact may be 25-90° C., and the first solvent may be tetrahydrofuran, diethyl ether, ethylene glycol dimethyl ether and dimethyl ether At least one of the oxymethanes is preferably tetrahydrofuran.

In some embodiments of the present invention, preferably, in step (2), the temperature of the second contact may be 0-90° C., and the second solvent may be tetrahydrofuran, diethyl ether, ethylene glycol dimethyl ether and dimethyl ether At least one of the oxymethanes is preferably tetrahydrofuran.

In some embodiments of the present invention, in step (2), the second contact preferably includes a third contact and a fourth contact performed in sequence, wherein the third contact may be performed at a temperature of 0-30°C, so The duration of the third contact may be 0.5-2 hours; the fourth contact may be performed at a temperature of 0-100° C., and the duration of the fourth contact may be 0.5-12 hours. The fourth contact is carried out in the presence of at least one basic substance and at least one alcohol, the basic substance is preferably an amine, more preferably a trialkylamine, further preferably triethylamine; the alcohol is preferably is a _C1 - _C6 alcohol, more preferably methanol. The molar ratio of the basic substance to the silane represented by the formula IV may be 1.0-1.2:1, and the molar ratio of the alcohol to the silane represented by the formula IV may be 1-5:1.

In some embodiments of the present invention, in step (2), the mixture obtained by the second contact can be separated by a conventional method, thereby obtaining the first external electron donor compound. As an example, the mixture obtained by the second contact in step (2) can be subjected to distillation, column chromatography or a combination of the two to obtain the first external electron donor compound.

In some embodiments of the present invention, the preparation method of the second external electron donor compound having the structure represented by formula II is not particularly limited, and conventional methods can be used to prepare, for example, the known literature (A.V.Lebedev , R.M.Minas'yan, A.M.Abramkin, V.D.Sheludyakov, N.E.Kuzmina, A.B.Lebedeva, G.E.Surikov, V.B.Rybakov.Synthesis and properties of functionalized alkylalkoxysilanes[J].Russian Journal of General Chemistry,2016,86(8).) method to prepare.

A second aspect of the present invention provides an olefin polymerization catalyst, the olefin polymerization catalyst comprising:

(1) a solid component, the solid component is obtained from a titanium-containing compound, a magnesium-containing compound and an internal electron donor compound through a contact reaction;

(2) organoaluminum compounds; and

(3) an external electron donor composition;

The external electron donor composition is the external electron donor composition described in the first aspect, the external electron donor composition contains a first external electron donor compound and a second external electron donor compound, the first external electron donor compound The types and amounts of the external electron donor compound and the second external electron donor compound can be selected according to the above, and will not be repeated here.

In some embodiments of the present invention, the solid component is obtained from a titanium-containing compound, a magnesium-containing compound and an internal electron donor compound through a contact reaction.

In some embodiments of the present invention, in order to obtain an olefin polymer with a higher rubber content and a higher melt index, preferably, the titanium-containing compound in terms of titanium element, the magnesium-containing compound in terms of magnesium element, and an internal donor The molar ratio of the electron body compound is 1:1-50:0.1-1.5, more preferably 1:5-40:0.2-1.2, still more preferably 1:10-30:0.5-1.

In some embodiments of the present invention, preferably, the magnesium-containing compound is provided in the form of a magnesium-containing support, and the titanium-containing compound and the internal electron donor compound are supported on the magnesium-containing support.

In some embodiments of the present invention, the preparation method of the solid component is not particularly limited, and conventional methods can be used to prepare the solid component. , CN1091748A, CN1109067A, CN1110281A, CN1199056A disclosed methods to prepare the solid component.

In some embodiments of the present invention, preferably, the preparation method of the solid component comprises:

(1) dispersing the magnesium-containing compound in a dispersion medium to obtain a magnesium-containing dispersion medium;

(2) carrying out the fifth contact with the magnesium-containing dispersion medium and the first titanium-containing compound and the first internal electron donor compound to obtain a first dispersion liquid;

(3) carrying out the sixth contact with the second titanium-containing compound and the second internal electron donor compound to obtain the second dispersion liquid;

(4) Removing the dispersion medium in the second dispersion liquid to obtain the solid component.

In some embodiments of the present invention, the magnesium-containing compound is selected from at least one of magnesium chloride, magnesium bromide and magnesium iodide, more preferably magnesium chloride.

In some embodiments of the present invention, the dispersion medium is selected from at least one of C ₅ -C ₁₂ alkanols and C ₆ -C ₁₂ alkanes, preferably isooctanol and/or decane.

Preferably, the dispersion medium is C ₅ -C ₁₂ alkanol and C ₆ -C ₁₂ alkane, more preferably isooctanol and decane; the C ₅ -C ₁₂ alkanol and the C ₆ - The weight ratio of C12 alkanes may be ₁ :0.5-2, more preferably 1:0.8-1.5.

In some embodiments of the present invention, preferably, the weight ratio of the magnesium-containing compound to the dispersion medium may be 1:5-20.

In some embodiments of the present invention, the first titanium-containing compound is at least one selected from titanate, for example, can be selected from tetramethyl titanate, tetraethyl titanate, tetrapropyl titanate and titanic acid At least one of tetrabutyl esters. Preferably, the first titanium compound is tetrabutyl titanate.

In some embodiments of the present invention, the second titanium-containing compound is selected from at least one of inorganic titanium compounds, for example, can be selected from titanium tetrahalide and/or titanium trihalide, preferably titanium tetrahalide, such as tetrachloride Titanium, titanium tetrabromide, titanium tetrafluoride, etc., more preferably titanium tetrachloride.

In some embodiments of the present invention, preferably, the molar ratio of the first titanium-containing compound to the second titanium-containing compound is 1:80-320.

In some embodiments of the present invention, the first internal electron donor compound and the second internal electron donor compound are each independently selected from at least one of phthalic acid diester type internal electron donor compounds, for example , can be selected from at least one of dialkyl phthalate type internal electron donor compounds, succinate type internal electron donor compounds and salicylate type internal electron donor compounds; preferably, the The first internal electron donor compound and the second internal electron donor compound are each independently selected from at least one of dialkyl phthalate type internal electron donor compounds, for example, can be selected from phthalate Di-tert-butyl formate, diisobutyl phthalate, di-n-butyl phthalate, di-n-propyl phthalate, diisopropyl phthalate and diethyl phthalate At least one of phthalates, more preferably at least one of diisobutyl phthalate, di-n-butyl phthalate and di-n-propyl phthalate; the first internal electron donor compound is The second internal electron donor compounds may be the same or different, and are preferably the same.

In some embodiments of the present invention, in order to obtain a solid catalyst component with good performance, preferably, the molar ratio of the first internal electron donor compound to the second internal electron donor compound may be 1:0.2-1. The composite internal electron donor (the first internal electron donor and the second internal electron donor are different) can realize the performance difference between various internal electron donors; adding the internal electron donor in batches (the first internal electron donor The same as the second internal electron donor) can make the loading of the internal electron donor firmer.

In some embodiments of the present invention, the fifth contact may be performed at a temperature of 100-140° C., and the duration of the first contact may be 0.5-3 hours.

In some embodiments of the present invention, the sixth contact may be performed at a temperature of 100-130° C., and the duration of the second contact may be 1-5 hours.

In some embodiments of the present invention, the molar ratio of the external electron donor composition to the titanium-containing compound calculated as titanium element is 2-50:1, preferably 5-30:1.

In some embodiments of the present invention, the molar ratio of the organoaluminum compound based on aluminum element to the titanium-containing compound based on titanium element is 10-1000:1, preferably 40-800:1.

In some embodiments of the present invention, in the olefin polymerization catalyst, the addition of aluminum (aluminum alkyl) will cause the originally supported internal electron donors to fall off, and the addition of external electron donors can just fill the gap. Such catalytically active titanium exhibits different catalytic properties due to its new coordination environment, thereby obtaining polyolefins with different properties. In the present invention, the first external electron donor compound and the second external electron donor compound are used in combination, and when the obtained olefin polymerization catalyst is used in the olefin polymerization reaction, impact polypropylene with high rubber content can be obtained, and the polypropylene also has Higher melt index.

In some embodiments of the present invention, the organoaluminum compound is preferably at least one of aluminum alkyls, more preferably at least one of aluminum trialkyls. The alkyl group is preferably a C ₁ -C ₆ alkyl group, more preferably at least one of ethyl, n-propyl, isopropyl, n-butyl, isobutyl and tert-butyl. Further preferably, the organoaluminum compound is triethylaluminum and/or triisobutylaluminum.

In some embodiments of the present invention, the use method of the olefin polymerization catalyst is not particularly limited, and the method used for olefin polymerization existing in the art can be used. In order to obtain a better catalytic effect, the solid component, The organoaluminum compound and the external electron donor compound are simultaneously added into the polymerization reaction system to form a catalyst through pre-complexation, which is used to catalyze the polymerization reaction.

In the present invention, when the external electron donor composition of the present invention is used, the first external electron donor compound and the second external electron donor compound are used in combination, and the obtained olefin polymerization catalyst is used in the olefin polymerization reaction, and the rubber content can be obtained. High impact polypropylene, and the polypropylene also has a high melt index, especially the impact polypropylene with a rubber content of 35-45% and a melt index of 30-80g/10min. The melt index is measured according to the test standard ASTM D1238, wherein the measurement conditions include: a temperature of 230° C. and a load of 2.16 kg.

A third aspect of the present invention provides an application of the above-mentioned olefin polymerization catalyst in an olefin polymerization reaction.

A fourth aspect of the present invention provides a method for preparing a polyolefin, the method comprising: performing a polymerization reaction of an olefin monomer in the presence of the above-mentioned olefin polymerization catalyst under the conditions of an olefin polymerization reaction.

In some embodiments of the present invention, the polymerization reaction may be a bulk polymerization reaction or a gas phase polymerization reaction. The olefin polymerization reaction can be carried out under conventional conditions, which are not particularly limited in the present invention.

Preferably, the conditions for the olefin polymerization reaction include: a polymerization temperature of 50-80° C., more preferably 65-75° C.; and a polymerization time of 1-3 hours, more preferably 1.5-2 hours.

Preferably, the olefin monomer is selected from the group consisting of ethylene, propylene and 1-butene, 2-butene, 2-methyl-1-butene, 3-methyl-1-butene, 2-methyl-2 -At least one of C ₄ -C ₈ α-olefins such as butene, 1-pentene, 2-pentene and 1-hexene, more preferably propylene.

In the method for preparing polyolefin provided by the present invention, by using the olefin polymerization catalyst of the present invention, polyolefin with higher rubber content and higher melt index can be obtained.

A fifth aspect of the present invention provides a polyolefin prepared by the method described in the fourth aspect.

In some embodiments of the present invention, preferably, the rubber content in the polyolefin is 35-45%, and the melt index of the polyolefin is 30-80 g/10min;

More preferably, the rubber content in the polyolefin is 35-44.5%, and the melt index of the polyolefin is 40-80 g/10min;

Further preferably, the rubber content in the polyolefin is 40-44.5%, and the melt index of the polyolefin is 70-78 g/10min.

The present invention will be described in detail below by means of examples.

In the following examples and comparative examples, unless otherwise specified, the raw materials used are all commercially available products.

In the following examples and comparative examples, the testing methods involved are as follows:

(1) The melt index of polypropylene is measured according to the test standard ASTM D1238, wherein the measurement conditions include: the temperature is 230°C, and the load is 2.16kg;

(2) The rubber content in polypropylene is determined with reference to GB/T 24282-2009, and the specific method is as follows:

An appropriate amount of polypropylene is dried and weighed, and the weight is recorded as m ₁ , then the polypropylene and xylene are mixed, heated and stirred at a reflux temperature of 140 ° C for 30 minutes until the polypropylene is fully dissolved, and filtered to obtain a filtrate and a gel; After drying, weigh and record the weight as m ₂ ; cool the filtrate to 25°C in a constant temperature water bath and keep the temperature constant for 30 minutes to fully crystallize the polypropylene in the filtrate, and then filter again to obtain a transparent filtrate; the xylene in the transparent filtrate is Evaporate to obtain xylene soluble matter, weigh, and record the weight as m ₃ , and the rubber content in polypropylene is (m ₂ +m ₃ )/m ₁ ×100%;

(3) The catalytic activity of the catalyst: the evaluation of the catalytic activity of the catalyst is carried out by a method in which the weight of the polypropylene obtained after polymerization is compared with the weight of the catalyst used;

(4) Component content analysis of the catalyst: the content of titanium element was measured by colorimetric method; the content of magnesium element was measured by titration method; the content of internal electron donor was measured by extraction method.

Preparation Examples 1-3 are used to illustrate the first external electron donor compound of the present invention and its preparation method.

Preparation Example 1

Preparation Example 1 is used to prepare the first external electron donor compound A represented by formula I-1:

(1) Preparation of Grignard reagent

Take a 500 ml three-necked flask with a magnetron, a spherical condenser and a constant pressure dropping funnel, add magnesium powder (28.8 g, 1.2 mol) and a little iodine under nitrogen protection; add ortho-bromine to the constant pressure dropping funnel Anisole (1.0 mol) and tetrahydrofuran (200 ml), then 5 ml of o-bromoanisole in tetrahydrofuran was added dropwise to the flask, stirred for 3-5 minutes to initiate the reaction; then o-bromoanisole was added dropwise tetrahydrofuran solution; after the dropwise addition is completed, heat under reflux for 1 hour to complete the preparation of Grignard reagent.

(2) Synthesis of Silane

Take a 2.5-liter three-necked flask with a magnetron and a spherical condenser, add dicyclohexyldichlorosilane (265 g, 1.0 mol) and 500 mL of tetrahydrofuran under nitrogen protection; place the flask in an ice-water bath, and then use a syringe to remove The above-mentioned Grignard reagent was slowly added to the flask; after the dropwise addition, the temperature was slowly raised to room temperature, and the reaction was performed for 12 hours; then the flask was placed in an ice-water bath again, and triethylamine (101 g, 1.0 mol) and methanol (100 mL) were added. ); finally refluxed for 6 hours to complete the reaction. The product was separated by distillation under reduced pressure, and the obtained product was determined to be the first external electron donor compound A represented by formula I-1 (the yield was 80% by weight) through hydrogen nuclear magnetic resonance spectroscopy.

Preparation Example 2

Preparation Example 2 is used to prepare the first external electron donor compound B represented by formula I-2:

代替邻溴苯甲醚，得到的产物经核磁共振氢谱确定为式I-2所示的第一外给电子体化合物B(收率为85重量％)。According to the method of Preparation Example 1, the difference is that in step (1), an equal amount of 1-bromo-2-methoxy-3-methylbenzene is used

In place of o-bromoanisole, the obtained product was determined to be the first external electron donor compound B represented by formula I-2 (the yield was 85% by weight) by hydrogen nuclear magnetic resonance spectroscopy.

Preparation Example 3

Preparation Example 3 is used to prepare the first external electron donor compound C represented by formula I-3:

代替邻溴苯甲醚，得到的产物经核磁共振氢谱确定为式I-3所示的第一外给电子体化合物C(收率为60重量％)。According to the method of Preparation Example 1, the difference is that in step (1), an equal amount of 1-bromo-2-methoxy-3-isopropylbenzene is used

In place of o-bromoanisole, the obtained product was identified as the first external electron donor compound C represented by formula I-3 (yield: 60% by weight) by hydrogen nuclear magnetic resonance spectroscopy.

Preparation Example 4 is used to illustrate the second external electron donor compound of the present invention and its preparation method.

Preparation Example 4

With reference to known literature (A.V.Lebedev, R.M.Minas'yan, A.M.Abramkin, V.D.Sheludyakov, N.E.Kuzmina, A.B.Lebedeva, G.E.Surikov, V.B.Rybakov.Synthesis and properties of functionalized alkylalkoxysilanes[J].Russian Journal of General Chemistry, 2016,86 ( The method disclosed in 8).) prepares the second external electron donor compound represented by formula II:

Examples 1-7 are used to illustrate the olefin polymerization catalyst and the polyolefin preparation method of the present invention.

The solid component that embodiment 1-7 and comparative example 1-4 use, its preparation method is as follows:

(1) in a reactor fully replaced by high-purity nitrogen, add 4.94g of anhydrous magnesium chloride, 18.9g of isooctanol and 30mL of decane successively, stir and heat up to 130 ° C, then maintain for 2 hours to obtain magnesium-containing dispersion medium;

(2) 2.65 g of tetrabutyl titanate and 10 mmol of diisobutyl phthalate were added to the dispersion medium containing magnesium, and the reaction was continued for 1 hour at a temperature of 130° C., and then cooled to room temperature (room temperature here). is 25°C) to obtain the first dispersion;

(3) add the titanium tetrachloride of 200mL in the reactor, stir and pre-cool to -20 ℃, after maintaining for 2 hours, drop the first dispersion into the titanium tetrachloride, start to heat up after the dropwise addition, The temperature was raised to 110°C within 2 hours, then 5mmol of diisobutyl phthalate was added, the reaction was continued for 2 hours at a temperature of 110°C, the reaction liquid was removed, 200 mL of titanium tetrachloride was added again, and reaction 2 After hours, a second dispersion is obtained;

(4) The reaction liquid in the second dispersion liquid was removed, and the obtained solid substance was washed with hexane at 60° C. 10 times, and after drying, the solid component Z was obtained.

In the solid component Z, the molar ratio of titanium tetrachloride based on titanium element, magnesium chloride based on magnesium element and diisobutyl phthalate is 1:22:0.85; the content of titanium element is 2.36wt% .

Example 1

(1) at 70 ℃, after the 5L autoclave was purged with high-purity nitrogen for 60min, the autoclave was replaced 3 times with propylene gas, and then 0.3MPa hydrogen and 15g ethylene were introduced; then 20mg solid group was added Divide Z, 6 mmol of triethylaluminum (Al/Ti molar ratio of 600), 0.19 mmol of the first external electron donor compound A and 0.01 mmol of the second external electron donor compound (the first external electron donor compound A The molar ratio to the second external electron donor compound is 20; the external electron donor composition is calculated as silicon element, and the Si/Ti molar ratio is 20), then 1000 g of propylene is added, and reacted at 70 ° C for 1 hour;

(2) mixing propylene and ethylene with a molar ratio of 1:1 in the gas mixing tank in advance, after the reaction of step (1) is finished, the remaining propylene in the autoclave is emptied and connected with the gas mixing tank, at 70 After reacting for 1 hour under stirring conditions of ℃, the obtained product was transferred to a 2000 mL round-bottomed flask, 500 mL of deionized water was added, stirred at 100 ℃ for 20 min, filtered with suction, and then dried in a vacuum oven at 70 ℃ After 12 hours, polypropylene powder particles are obtained, and the specific performance test results of the polypropylene powder particles are shown in Table 1.

Example 2

According to the method of Example 1, the difference is that the addition amount of the first external electron donor compound A is 0.195 mmol, and the addition amount of the second external electron donor compound is 0.005 mmol (the first external electron donor compound A and the first external electron donor compound The molar ratio of the two external electron donor compounds is 40) to obtain polypropylene powder particles. The specific performance test results of the polypropylene powder particles are shown in Table 1.

Example 3

According to the method of Example 1, the difference is that the addition amount of the first external electron donor compound A is 0.196 mmol, and the addition amount of the second external electron donor compound is 0.004 mmol (the first external electron donor compound A and the first external electron donor compound The molar ratio of the two external electron donor compounds is 50) to obtain polypropylene powder particles. The specific performance test results of the polypropylene powder particles are shown in Table 1.

Example 4

According to the method of Example 1, the difference is that the addition amount of the first external electron donor compound A is 0.197 mmol, and the addition amount of the second external electron donor compound is 0.003 mmol (the first external electron donor compound A and the The molar ratio of the two external electron donor compounds is 60) to obtain polypropylene powder particles. The specific performance test results of the polypropylene powder particles are shown in Table 1.

Example 5

(1) at 70 ℃, after the 5L autoclave was purged with high-purity nitrogen for 60min, the autoclave was replaced 3 times with propylene gas, and then 0.3MPa hydrogen and 15g ethylene were introduced; then 20mg solid group was added Z, 6 mmol of triethylaluminum (Al/Ti molar ratio of 600), 0.195 mmol of the first external electron donor compound B and 0.005 mmol of the second external electron donor compound (the first external electron donor compound B and the molar ratio of the second external electron donor compound is 40; the external electron donor composition is calculated in terms of silicon element, and the Si/Ti molar ratio is 20), then 1000 g of propylene is added and reacted at 70 ° C for 1 hour;

(2) mixing propylene and ethylene with a molar ratio of 1:1 in the gas mixing tank in advance, after the reaction of step (1) is finished, the remaining propylene in the autoclave is emptied and connected with the gas mixing tank, at 70 After reacting for 1 hour under stirring conditions of ℃, the obtained product was transferred to a 2000 mL round-bottomed flask, 500 mL of deionized water was added, stirred at 100 ℃ for 20 min, filtered with suction, and then dried in a vacuum oven at 70 ℃ After 12 hours, polypropylene powder particles are obtained, and the specific performance test results of the polypropylene powder particles are shown in Table 1.

Example 6

(1) at 70 ℃, after the 5L autoclave was purged with high-purity nitrogen for 60min, the autoclave was replaced 3 times with propylene gas, and then 0.3MPa hydrogen and 15g ethylene were introduced; then 20mg solid group was added Divide Z, 6 mmol of triethylaluminum (Al/Ti molar ratio of 600), 0.195 mmol of the first external electron donor compound C and 0.005 mmol of the second external electron donor compound (the first external electron donor compound C and the molar ratio of the second external electron donor compound is 40; the external electron donor composition is calculated in terms of silicon element, and the Si/Ti molar ratio is 20), then 1000 g of propylene is added and reacted at 70 ° C for 1 hour;

(2) mixing propylene and ethylene with a molar ratio of 1:1 in the gas mixing tank in advance, after the reaction of step (1) is finished, the remaining propylene in the autoclave is emptied and connected with the gas mixing tank, at 70 After reacting for 1 hour under stirring conditions of ℃, the obtained product was transferred to a 2000 mL round-bottomed flask, 500 mL of deionized water was added, stirred at 100 ℃ for 20 min, filtered with suction, and then dried in a vacuum oven at 70 ℃ After 12 hours, polypropylene powder particles are obtained, and the specific performance test results of the polypropylene powder particles are shown in Table 1.

Example 7

According to the method of Example 2, the difference is that the external electron donor composition is calculated as silicon element, and the Si/Ti molar ratio is 40 to obtain polypropylene powder particles. The specific performance test results of the polypropylene powder particles are shown in the table. 1 shown.

Comparative Example 1

According to the method of Example 2, the difference is that 0.2 mmol of the first external electron donor compound A is added, and the second external electron donor compound is not added (the first external electron donor compound A is calculated as silicon element, Si/Ti The molar ratio is 20) to obtain polypropylene powder particles. The specific performance test results of the polypropylene powder particles are shown in Table 1.

Comparative Example 2

According to the method of Example 2, the difference is that the first external electron donor compound A is not added, and 0.2 mmol of the second external electron donor compound is added (the second external electron donor compound is calculated as silicon element, Si/Ti moles ratio of 20) to obtain polypropylene powder particles, and the specific performance test results of the polypropylene powder particles are shown in Table 1.

Comparative Example 3

According to the method of Example 2, the difference is that the addition amount of the first external electron donor compound A is 0.178 mmol, and the addition amount of the second external electron donor compound is 0.022 mmol (the first external electron donor compound A and the first external electron donor compound The molar ratio of the two external electron donor compounds is 8) to obtain polypropylene powder particles. The specific performance test results of the polypropylene powder particles are shown in Table 1.

Comparative Example 4

According to the method of Example 2, the difference is that the external electron donor composition used is 9,9-bis(methoxymethyl)fluorene (BMF), tetraethoxysilane (TEOS) (moles of BMF and TEOS) The ratio is 2.5:97.5, and the molar ratio of the addition amount of the external electron donor composition to Ti is 15) to obtain polypropylene powder particles. The specific performance test results of the polypropylene powder particles are shown in Table 1.

Table 1

It can be seen from the results in Table 1 that in Examples 1-4, as the ratio of the first external electron donor compound to the second external electron donor compound gradually increased, the activity of the catalyst remained basically unchanged, and remained at a relatively high level. The high activity level; the melt index of the polymer showed a gradually decreasing trend; and the rubber content of the polymer showed a trend of increasing first and then decreasing. When the molar ratio of the first external electron donor compound to the second external electron donor compound is 40:1, the comprehensive properties of the polymer reach the optimum value (melt index is 73.9g/10min, rubber content is 44.3%).

In Examples 2, 5 and 6, when the molar ratio of the first external electron donor compound and the second external electron donor compound is within the preferred range of the present invention, the rubber content and melt index of the impact polypropylene can be further improved.

In Example 7, when the addition amount of the external electron donor composition is increased, the melt index of the polymer will be seriously reduced, and the impact polypropylene with high rubber content and high melt index cannot be obtained.

In Comparative Examples 1-3, when the first external electron donor compound is used alone, the polymer has a relatively high rubber content, but the melt index is extremely low; the second external electron donor compound or the second external electron donor compound is used alone When the added amount of the compound is too high, the obtained polymer will suffer from serious blocking phenomenon, which is unfavorable for the industrial production of the polymer.

Comparative Example 4 is an industrially used experimental scheme for preparing high melt index polypropylene. Although the melt index of the obtained polymer is relatively high, a polymer with high rubber content cannot be obtained by using the external electron donor composition.

To sum up, the olefin polymerization catalyst obtained by using the external electron donor composition provided by the present invention can be applied to the production of impact-resistant polypropylene, and can realize the production of polypropylene with both high rubber content and high melt index. The polymer does not block and has good particle morphology.

The preferred embodiments of the present invention have been described above in detail, however, the present invention is not limited thereto. Within the scope of the technical concept of the present invention, a variety of simple modifications can be made to the technical solutions of the present invention, including combining various technical features in any other suitable manner. These simple modifications and combinations should also be regarded as the content disclosed in the present invention. All belong to the protection scope of the present invention.

Claims (31)

1. An external electron donor composition, characterized in that the external electron donor composition contains a first external electron donor compound and a second external electron donor compound, wherein the first external electron donor The compound is selected from at least one of the compounds having the structure shown in formula I:

In formula I, R ¹ and R ² are each independently selected from any one of C ₁ -C ₁₀ alkane, C ₃ -C ₁₂ cycloalkyl and C ₆ -C ₂₀ aryl; R ³ , R ⁴ , R ⁵ and R ⁶ are each independently selected from hydrogen, a halogen group, a C ₁ -C ₁₀ alkane group, a C ₃ -C ₁₂ cycloalkyl group, and a C ₆ -C ₂₀ aryl group any of the R ⁷ and R ⁸ are each independently selected from any one of C ₁ -C ₅ chain alkyl groups; R ¹ and R ² are the same or different, R ³ , R ⁴ , R ⁵ , R ⁶ are the same or different, R ⁷ and R ⁸ are the same or different; The second external electron donor compound has the structure shown in formula II:

The molar ratio of the first external electron donor compound and the second external electron donor compound is 10-100:1. 2. The external electron donor composition according to claim 1, wherein, in formula I, R ¹ and R ² are each independently selected from methyl, ethyl, isopropyl, cyclohexyl, phenyl, 2 , any one of 6-dimethylphenyl and 2,6-diisopropylphenyl. 3. The external electron donor composition of claim 2, wherein, in formula I, R ¹ and R ² are each independently cyclohexyl. 4. The external electron donor composition of claim 1, wherein, in formula I, R ³ , R ⁴ , R ⁵ and R ⁶ are each independently selected from hydrogen, fluorine, chlorine, bromine, iodine, methyl Any of radical, ethyl, isopropyl, tert-butyl, isobutyl, cyclopentyl, cyclohexyl, phenyl, 2,6-dimethylphenyl and 2,6-diisopropylphenyl A sort of. 5. The external electron donor composition of claim 4, wherein, in formula I, R ³ , R ⁴ and R ⁵ are each independently hydrogen, and R ⁶ is selected from hydrogen, methyl, ethyl and iso any of the propyl groups. 6. The external electron donor composition according to claim 1, wherein, in formula I, R ⁷ and R ⁸ are each independently selected from any one of methyl, ethyl, n-propyl and isopropyl kind. 7. The external electron donor composition of claim 6, wherein, in formula I, R ⁷ and R ⁸ are each independently methyl. 8. The external electron donor composition according to any one of claims 1-7, wherein the first external electron donor compound is selected from the compound represented by formula I-1, the compound represented by formula I-2 At least one of the compound and the compound shown in formula I-3:

9. The external electron donor composition according to any one of claims 1-7, wherein the molar ratio of the first external electron donor compound and the second external electron donor compound is 10-80 :1. 10 . The external electron donor composition of claim 9 , wherein the molar ratio of the first external electron donor compound and the second external electron donor compound is 20-60:1. 11 . 11. An olefin polymerization catalyst, characterized in that the olefin polymerization catalyst contains: (1) a solid component, the solid component is obtained from a titanium-containing compound, a magnesium-containing compound and an internal electron donor compound through a contact reaction; (2) organoaluminum compounds; and (3) External electron donor composition; the external electron donor composition is the external electron donor composition described in any one of claims 1-10. 12. The olefin polymerization catalyst according to claim 11, wherein the molar ratio of the titanium-containing compound in terms of titanium element, the magnesium-containing compound in terms of magnesium element and the internal electron donor compound is 1: 1-50: 0.1-1.5. 13. The olefin polymerization catalyst according to claim 12, wherein the molar ratio of the titanium-containing compound in terms of titanium element, the magnesium-containing compound in terms of magnesium element and the internal electron donor compound is 1: 5-40: 0.2-1.2. 14. The olefin polymerization catalyst according to claim 13, wherein the molar ratio of the titanium-containing compound in terms of titanium element, the magnesium-containing compound in terms of magnesium element and the internal electron donor compound is 1: 10-30: 0.5-1. 15. The olefin polymerization catalyst according to claim 11, wherein the titanium-containing compound is selected from the group consisting of tetramethyl titanate, tetraethyl titanate, tetrapropyl titanate, tetrabutyl titanate, titanium tetrachloride , at least one of titanium tetrabromide and titanium tetrafluoride. 16. The olefin polymerization catalyst according to claim 15, wherein the titanium-containing compound is tetrabutyl titanate and/or titanium tetrachloride. 17. The olefin polymerization catalyst of claim 11, wherein the magnesium-containing compound is selected from at least one of magnesium chloride, magnesium bromide, and magnesium iodide. 18. The olefin polymerization catalyst according to claim 17, wherein the magnesium-containing compound is magnesium chloride. 19. The olefin polymerization catalyst according to claim 11, wherein the internal electron donor compound is selected from the group consisting of di-tert-butyl phthalate, diisobutyl phthalate, and di-n-butyl phthalate , at least one of di-n-propyl phthalate, diisopropyl phthalate and diethyl phthalate. 20. The olefin polymerization catalyst according to claim 19, wherein the internal electron donor compound is among diisobutyl phthalate, di-n-butyl phthalate and di-n-propyl phthalate at least one of. 21. The olefin polymerization catalyst according to any one of claims 11-20, wherein the molar ratio of the external electron donor composition to the titanium-containing compound in terms of titanium element is 2-50:1. 22. The olefin polymerization catalyst according to claim 21, wherein the molar ratio of the external electron donor composition to the titanium-containing compound in terms of titanium element is 5-30:1. 23. The olefin polymerization catalyst according to any one of claims 11-20, wherein the molar ratio of the organoaluminum compound in terms of aluminum element to the titanium-containing compound in terms of titanium element is 10-1000: 1. 24. The olefin polymerization catalyst according to claim 23, wherein the molar ratio of the organoaluminum compound in terms of aluminum element to the titanium-containing compound in terms of titanium element is 40-800:1. 25. The olefin polymerization catalyst according to any one of claims 11-20, wherein the organoaluminum compound is selected from the group consisting of triethylaluminum, tri-n-propylaluminum, triisopropylaluminum, triisobutylaluminum , at least one of tri-n-butylaluminum and tri-tert-butylaluminum. 26. The olefin polymerization catalyst according to claim 25, wherein the organoaluminum compound is triethylaluminum and/or triisobutylaluminum. 27. The use of an olefin polymerization catalyst as claimed in any one of claims 11-26 in an olefin polymerization reaction. 28. A method for preparing polyolefin, characterized in that the method comprises: under olefin polymerization reaction conditions, in the presence of the olefin polymerization catalyst according to any one of claims 11-26, olefin monomer Carry out a polymerization reaction. 29. The method according to claim 28, wherein the conditions of the olefin polymerization reaction include: the polymerization temperature is 50-80°C; and the polymerization time is 1-3 hours. 30. The method according to claim 29, wherein the conditions of the olefin polymerization reaction comprise: the polymerization temperature is 65-75°C; and the polymerization time is 1.5-2 hours. 31. The method of claim 28, wherein the olefin monomer is selected from the group consisting of ethylene and propylene.