Olefin polymerization catalyst and preparation method thereof

Abstract

The present invention discloses an olefin polymerization catalyst and a preparation method thereof. The olefin polymerization catalyst is used to prepare polypropylene thermoplastic elastomers. The olefin polymerization catalyst comprises a metal chloride compound, a transition metal component, and a non-transition metal component; the transition metal component is titanium tetrahalide and / or titanium alkoxide, and the non-transition metal component is a magnesium-containing compound; the metal chloride is selected from at least one of FeCl2, ZnCl2, CuCl2, PdCl2, and MnCl2. The olefin polymerization catalyst of the present invention has high initial and overall activity, and produces polypropylene particles with high porosity. The catalyst can be used in the synthesis process of polypropylene thermoplastic elastomers to produce polypropylene thermoplastic elastomers with a high rubber content.

Description

Technical Field

[0001] The present invention relates to an olefin polymerization catalyst, a preparation method of the olefin polymerization catalyst and application of the olefin polymerization catalyst in polypropylene thermoplastic elastomer. Background Art

[0002] To improve polypropylene's poor low-temperature toughness, introducing a rubber component with excellent impact toughness is an effective approach. In particular, heterogeneous copolymerized polypropylene (impact-resistant copolymerized polypropylene) obtained by sequentially carrying out propylene homopolymerization and ethylene / propylene copolymerization during the polymerization process using a continuous polymerization method has been widely used in the automotive and home appliance sectors. Further increasing the rubber content in the heterogeneous copolymerized polypropylene can significantly improve its performance, resulting in polypropylene thermoplastic elastomers. However, synthesizing heterogeneous copolymerized polypropylene with a rubber content greater than 35% by weight is difficult to achieve using most existing process equipment. The main reason for this is that when the rubber content is high, the rubber migrates to the surface of the polymer particles, leading to adhesion between the polymer particles and between the polymer particles and the reactor, affecting polymer transport and posing the risk of reactor blockage. To address these issues, improvements in catalysts and polymerization processes are two key approaches. Increasing the porosity of the polypropylene particles obtained after propylene homopolymerization (i.e., reducing the bulk density of the polypropylene particles) or adopting a multi-zone polymerization process can both increase the rubber content in the heterogeneous copolymerized polypropylene, resulting in polypropylene thermoplastic elastomers with high rubber content.

[0003] Olefin polymerization catalysts have always been one of the main driving forces for the advancement of polyolefin technology and the upgrading of product performance. The composition and preparation method of the catalyst can affect its olefin polymerization activity and kinetic behavior, thereby changing the particle properties of the polymer particles such as porosity. A literature report (Highly efficient FeCl3 doped Mg(OEt)2 / TiCl4-based Ziegler–Natta catalysts for ethylene polymerization. Designed Monomers and Polymers, 2015, 18(7), 599-610) reported that FeCl3 and SiCl4 were doped into the catalyst Mg(OEt)2 / TiCl4, which had the effect of increasing the ethylene polymerization activity by 2.4 times, increasing the weight-average molecular weight and particle bulk density of polyethylene, and reducing the content of low molecular weight components. Summary of the Invention

[0004] The present invention provides an olefin polymerization catalyst and a preparation method thereof, thereby improving the initial and overall activity of the catalyst and producing polypropylene particles with high porosity. This catalyst can be used in the synthesis of polypropylene thermoplastic elastomers to produce polypropylene thermoplastic elastomers with a high rubber content.

[0005] To achieve the above-mentioned object, the present invention provides an olefin polymerization catalyst, which is used to prepare polypropylene thermoplastic elastomer. The olefin polymerization catalyst contains a metal chloride compound, a transition metal component and a non-transition metal component; the transition metal component is titanium tetrahalide and / or alkoxy titanium, and the non-transition metal component is a magnesium-containing compound; the metal chloride is selected from at least one of FeCl2, ZnCl2, CuCl2, PdCl2, and MnCl2.

[0006] The olefin polymerization catalyst of the present invention has a metal chloride content of 0.5-50% by weight, and a total content of metal elements in the transition metal component and the non-transition metal component of the catalyst is 2-80% by weight, based on the total weight of the catalyst.

[0007] Preferably, based on the total weight of the olefin polymerization catalyst, the content of the metal chloride is 5-20 wt%, and the total content of the metal elements in the transition metal component and the non-transition metal component is 10-20 wt%.

[0008] The olefin polymerization catalyst of the present invention has a transition metal element content of 0.5-10 wt % in the transition metal component and a non-transition metal element content of 2-30 wt % in the non-transition metal component, based on the total weight of the olefin polymerization catalyst.

[0009] In the olefin polymerization catalyst of the present invention, the particle size of the metal chloride is 0.05 to 1.0 micron.

[0010] In the olefin polymerization catalyst of the present invention, the titanium tetrahalide is at least one of TiCl4, TiBr4 and TiI4.

[0011] The olefin polymerization catalyst of the present invention, the general formula of the titanium alkoxide is R 4 p Ti(OR 5 ) 4-p , R 4 and R 5 Each is independently a C1-C4 alkyl group, and p is an integer of 0-3; preferably, the alkoxytitanium is at least one of tetrabutyl titanate, methyltriethoxytitanium, methyltrimethoxytitanium and tetraethyl titanate.

[0012] The olefin polymerization catalyst of the present invention, the magnesium-containing compound is a compound having the general formula MgX1 2 magnesium halide and / or general formula RMgX 2 Grignard reagent; in MgX 1 2 in, X 1 is F, Cl, Br or I; in RMgX 2 In the example, R is C1-C 10 The alkyl group, X 2 is F, Cl, Br or I.

[0013] The olefin polymerization catalyst of the present invention further contains an internal electron donor compound; preferably, the internal electron donor compound is a diether compound and / or a carboxylate compound.

[0014] The olefin polymerization catalyst of the present invention further comprises a co-catalyst, wherein the co-catalyst is an alkyl aluminum; the general formula of the aluminum-containing compound is Al(OR′) q R″ 3-q , R' and R" are each independently C2-C 10 alkyl, 0≤q≤3.

[0015] The present invention also provides a method for preparing an olefin polymerization catalyst, which comprises the following steps:

[0016] (1) reacting a metal chloride with a non-transition metal component magnesium compound at 30-150° C. for 1-50 hours to obtain a magnesium complex;

[0017] (2) The magnesium complex is subjected to coordination reaction with titanium tetrahalide and / or titanium alkoxide to obtain an olefin polymerization catalyst.

[0018] In the preparation method of the olefin polymerization catalyst of the present invention, in step (1), the weight ratio of the amount of the metal chloride to the amount of the non-transition metal component magnesium-containing compound is 1:0.5-99, preferably 1:0.5-50.

[0019] The preparation method of the olefin polymerization catalyst of the present invention comprises the following steps: firstly mixing the magnesium complex with a portion of titanium tetrahalide and / or a portion of titanium alkoxide and reacting the mixture at -20 to 20°C for 0.5 to 2 hours; then raising the temperature to 80 to 130°C for reaction for 1 to 4 hours; then separating the reaction product into a solid and a liquid; and reacting the obtained solid product with the remaining portion of titanium tetrahalide and / or the remaining portion of titanium alkoxide at 80 to 130°C for 1 to 4 hours.

[0020] The method for preparing an olefin polymerization catalyst of the present invention, wherein the part of the alkoxy titanium and the remaining part of the alkoxy titanium are each independently at least one of Ti(OEt)Cl3, Ti(OEt)2Cl2, Ti(OEt)3Cl, Ti(OEt)4 and Ti(OBu)4.

[0021] The method for preparing an olefin polymerization catalyst of the present invention, wherein the mass ratio of the part of titanium tetrahalide to the remaining part of titanium tetrahalide is 1:0.1-10.

[0022] The preparation method of the olefin polymerization catalyst of the present invention further includes adding an internal electron donor compound. The internal electron donor compound is added in the following manner: after the magnesium complex and a portion of the transition metal component are reacted at -20 to 20°C for 0.5 to 2 hours, the internal electron donor compound is added to the reaction system.

[0023] In the method for preparing the olefin polymerization catalyst of the present invention, the mass ratio of the magnesium complex to titanium tetrahalide and / or titanium alkoxide is 1:1-100.

[0024] After in-depth research, the present inventors discovered that when the olefin polymerization catalyst of the present invention is used in an olefin polymerization reaction, high-porosity polypropylene primary particles can be obtained, solving the problem of low efficiency in the subsequent ethylene-propylene copolymerization reaction and ultimately enabling the reaction and synthesis of a polypropylene thermoplastic elastomer with a high rubber content. The olefin polymerization catalyst of the present invention has high initial activity and can generate more pores in the polymer without causing polymer fragmentation. The resulting polypropylene particles have a low bulk density (<0.35 g / mL, significantly less than the 0.42 g / mL of conventional polypropylene) and a high porosity. During the subsequent ethylene-propylene copolymerization process, monomer diffusion and rubber filling provide more "pores," thereby facilitating the preparation of high-rubber-content polypropylene thermoplastic elastomer particles with a well-defined particle morphology. Numerous experimental results have also verified the effectiveness of the olefin polymerization catalyst, resulting in the synthesis of polypropylene thermoplastic elastomers with a rubber mass percentage exceeding 50%, and even approaching 70%. The olefin polymerization catalyst of the present invention overcomes the bottleneck of low rubber content and polymer particle sticking to the reactor during the polypropylene autoclave alloy production process, enabling the in-autoclave synthesis of high-rubber-content polypropylene thermoplastic elastomers, and has great industrial application prospects. DETAILED DESCRIPTION

[0025] The present invention is further described below with reference to the examples. These examples are intended to illustrate the present invention only and are not intended to limit the scope of the present invention. Experimental methods in the following examples where specific conditions are not specified are generally performed in accordance with conventional conditions in the art or the conditions recommended by the manufacturer; the raw materials and reagents used, unless otherwise specified, are all commercially available from conventional markets. Any non-substantial changes and substitutions made by those skilled in the art based on the present invention fall within the scope of protection claimed in the present invention.

[0026] Evaluation and analysis methods:

[0027] The content of transition metal elements in olefin polymerization catalyst was determined by ultraviolet spectrophotometry.

[0028] The content of magnesium in olefin polymerization catalyst was determined by titration method as follows: 50 mg of catalyst was dissolved in 10 mL of sulfuric acid solution under nitrogen protection, heated to boiling for 10 minutes, and then filtered to remove insoluble matter. -1 The titration is carried out with EDTA. Eriochrome black T is used as an indicator during the titration process. The titration endpoint is when the color of the solution containing the catalyst changes to blue-purple. The amount of EDTA used in the entire titration process is counted as V (mL). The magnesium content is then (0.01×V÷10)×24.3÷(50×10-3).

[0029] The titanium content in the olefin polymerization catalyst is measured by a spectrophotometer, specifically as follows: 50 mg of the catalyst is taken, and under nitrogen protection, the catalyst is dissolved in 10 mL of sulfuric acid solution, heated to boiling for 10 minutes, and then filtered to remove insoluble matter. The absorbance of the solution at a fixed wavelength (410 nm) is then measured by a spectrophotometer. The concentration of the titanium or zirconium element can be obtained by comparing the absorbance at 410 nm with that of the standard curve, and the titanium content in the olefin polymerization catalyst can be calculated.

[0030] The rubber content in the application example is determined by the ratio between the mass of the absorbed ethylene propylene gas mixture and the total mass of the polymer.

[0031] Example 1

[0032] This embodiment is used to illustrate the olefin polymerization catalyst and its preparation method, as well as the polyolefin resin composition and its preparation method provided by the present invention.

[0033] (1) Preparation method of olefin polymerization catalyst:

[0034] ① Disperse 4.0 g of anhydrous magnesium chloride (MgCl2) and 13.0 mL of isooctyl alcohol in 90 mL of decane. Heat to 130°C to form a transparent solution. React at 130°C for 1 hour to obtain a magnesium chloride alcoholate. Add the magnesium chloride alcoholate dropwise to a suspension of 2.0 g of FeCl2 in 20 mL of decane. React at 60°C for 4 hours to obtain a magnesium complex.

[0035] ② The magnesium complex described in step ① was added dropwise to 200 mL of titanium tetrachloride at -20°C over a 1-hour period, followed by a constant temperature reaction at -20°C for 1.0 hour. The temperature was then slowly raised to 120°C, and 0.2 mL of diisobutyl phthalate (the molar ratio of diisobutyl phthalate to magnesium in the magnesium complex was 0.15:1) was added. The reaction was then constant temperature reacted at 120°C for 1.5 hours. After the reaction was complete, the liquid was filtered, and 240 mL of titanium tetrachloride was added again, followed by a constant temperature reaction at 120°C for 2.0 hours. Finally, the catalyst was washed five times with hexane and dried to obtain an olefin polymerization catalyst, designated A1. Testing revealed a Ti content of 1.2% by weight and a magnesium content of 10% by weight.

[0036] Wherein, the FeCl2 described in step ① has a particle size of 0.1 to 0.5 microns.

[0037] (2) Catalytic propylene polymerization:

[0038] Under vacuum, 1000 g of liquid propylene monomer was added to a reactor. Then, at 30°C, 0.25 mol of triethylaluminum, 20 mg of olefin polymerization catalyst A1, and 0.2 g of hydrogen were added sequentially. The reaction temperature was then raised to 70°C and the reaction was allowed to proceed for 0.1 hour. 100 g of polymer was obtained with a polymerization activity of 30 kg / gTi. Testing revealed a bulk density of 0.20 g / mL.

[0039] Under vacuum, 1000 g of liquid propylene monomer was added to a reactor. Then, at 30°C, 0.25 mol of triethylaluminum, 20 mg of olefin polymerization catalyst A1, and 0.2 g of hydrogen were added sequentially. The reaction temperature was then raised to 70°C and the reaction was allowed to proceed for 1 hour. 600 g of polymer was obtained with a polymerization activity of 1436 kg / gTi. Testing revealed a bulk density of 0.30 g / mL.

[0040] Under vacuum, 1000 g of liquid propylene monomer was added to a reactor. Then, at 30°C, 0.25 mol of triethylaluminum, 20 mg of olefin polymerization catalyst A1, and 0.2 g of hydrogen were added sequentially. The reaction temperature was then raised to 70°C and the reaction was allowed to proceed for 2 hours. 800 g of polymer was obtained with a polymerization activity of 1915 kg / gTi. Testing revealed a bulk density of 0.34 g / mL.

[0041] Comparative Example 1

[0042] This comparative example is used to illustrate a reference olefin polymerization catalyst and its preparation method and its catalytic propylene polymerization reaction.

[0043] An olefin polymerization catalyst and a polyolefin resin composition were prepared according to the method of Example 1, except that FeCl2 was not added during the preparation of the olefin polymerization catalyst in this comparative example. The specific steps are as follows:

[0044] (1) Preparation method of olefin polymerization catalyst:

[0045] ① Disperse 4.0 g of anhydrous magnesium chloride MgCl2 and 13.0 mL of isooctyl alcohol in 90 mL of decane, heat to 130°C to form a transparent solution, and react at 130°C for 1.0 hour to obtain magnesium chloride alcoholate.

[0046] ② The magnesium complex described in step ① was added dropwise to 200 mL of titanium tetrachloride at -20°C over a period of 1 hour, followed by a constant temperature reaction at -20°C for 1.0 hour. The temperature was then slowly raised to 120°C, and 0.2 mL of diisobutyl phthalate (the molar ratio of diisobutyl phthalate to magnesium in the magnesium complex was 0.15:1) was added. The reaction was then continued at 120°C for 1.5 hours. After the reaction was complete, the liquid was filtered, and 240 mL of titanium tetrachloride was added, followed by a constant temperature reaction at 120°C for 2.0 hours. Finally, the mixture was washed five times with hexane and dried to obtain an olefin polymerization catalyst, designated B1. Testing revealed a Ti content of 2.3% by weight and a magnesium content of 18% by weight.

[0047] (2) Catalytic propylene polymerization:

[0048] Under vacuum, 1000 g of liquid propylene monomer was added to a reactor. Then, at 30°C, 0.25 mol of triethylaluminum, 20 mg of olefin polymerization catalyst B1, and 0.2 g of hydrogen were added sequentially. The reaction temperature was then raised to 70°C and allowed to react for 0.1 hour. 60 g of polymer was obtained, with a polymerization activity of 14.4 kg / g Ti. Testing revealed a bulk density of 0.35 g / mL.

[0049] Under vacuum, 1000 g of liquid propylene monomer was added to a reactor. Then, at 30°C, 0.25 mol of triethylaluminum, 20 mg of olefin polymerization catalyst B1, and 0.2 g of hydrogen were added in sequence. The reaction temperature was then raised to 70°C and the reaction was allowed to proceed for 1 hour. 400 g of polymer was obtained with a polymerization activity of 957.4 kg / gTi. Testing revealed a bulk density of 0.42 g / mL.

[0050] Under vacuum, 1000 g of liquid propylene monomer was added to a reactor. Then, at 30°C, 0.25 mol of triethylaluminum, 20 mg of olefin polymerization catalyst B1, and 0.2 g of hydrogen were added sequentially. The reaction temperature was then raised to 70°C and the reaction was allowed to proceed for 2 hours. 650 g of polymer was obtained with a polymerization activity of 1556 kg / gTi. Testing revealed a bulk density of 0.43 g / mL.

[0051] Example 2

[0052] This embodiment is used to illustrate the olefin polymerization catalyst and its preparation method, as well as the polyolefin resin composition and its preparation method provided by the present invention.

[0053] (1) Preparation method of olefin polymerization catalyst:

[0054] ① Disperse 4.0 g of anhydrous magnesium chloride (MgCl2) and 13.0 mL of isooctyl alcohol in 90 mL of decane. Heat to 130°C to form a transparent solution. React at 130°C for 1 hour to obtain a magnesium chloride alcoholate. Add the magnesium chloride alcoholate dropwise to a suspension of 1.0 g of ZnCl2 in 20 mL of decane. React at 60°C for 4 hours to obtain a magnesium complex.

[0055] ② The magnesium complex described in step ① was added dropwise to 200 mL of titanium tetrachloride at 10°C for 1 hour, followed by a constant temperature reaction at -20°C for 1.0 hour. The temperature was then slowly raised to 120°C, and 0.2 mL of diisobutyl phthalate (the molar ratio of diisobutyl phthalate to magnesium in the magnesium complex was 0.15:1) was added. The reaction was then continued at 120°C for 1.5 hours. After the reaction was complete, the liquid was filtered, and 240 mL of titanium tetrachloride was added again. The reaction was continued at 120°C for 2.0 hours. Finally, the catalyst was washed five times with hexane and dried to obtain an olefin polymerization catalyst, designated A2. Testing revealed a Ti content of 1.6% by weight and a magnesium content of 14% by weight.

[0056] Wherein, the ZnCl2 described in step ① has a particle size of 0.05 to 0.1 microns.

[0057] (2) Catalytic propylene polymerization:

[0058] Under vacuum, 1000 g of liquid propylene monomer was added to a reactor. Then, at 30°C, 0.25 mol of triethylaluminum, 20 mg of olefin polymerization catalyst A2, and 0.2 g of hydrogen were added sequentially. The reaction temperature was then raised to 70°C and the reaction was allowed to proceed for 0.1 hour. 110 g of polymer was obtained with a polymerization activity of 33 kg / gTi. Testing revealed a bulk density of 0.18 g / mL.

[0059] Under vacuum, 1000 g of liquid propylene monomer was added to a reactor. Then, at 30°C, 0.25 mol of triethylaluminum, 20 mg of olefin polymerization catalyst A2, and 0.2 g of hydrogen were added sequentially. The reaction temperature was then raised to 70°C and the reaction was allowed to proceed for 1 hour. 610 g of polymer was obtained with a polymerization activity of 1460 kg / gTi. Testing revealed a bulk density of 0.31 g / mL.

[0060] Under vacuum, 1000 g of liquid propylene monomer was added to a reactor. Then, at 30°C, 0.25 mol of triethylaluminum, 20 mg of olefin polymerization catalyst A2, and 0.2 g of hydrogen were added sequentially. The reaction temperature was then raised to 70°C and the reaction was allowed to proceed for 2 hours. 780 g of polymer was obtained with a polymerization activity of 1867 kg / gTi. Testing revealed a bulk density of 0.33 g / mL.

[0061] Example 3

[0062] This embodiment is used to illustrate the olefin polymerization catalyst and its preparation method, as well as the polyolefin resin composition and its preparation method provided by the present invention.

[0063] (1) Preparation method of olefin polymerization catalyst:

[0064] ① Disperse 4.0 g of anhydrous magnesium chloride (MgCl2) and 13.0 mL of isooctyl alcohol in 90 mL of decane. Heat to 130°C to form a transparent solution. React at 130°C for 1 hour to obtain a magnesium chloride alcoholate. Then, add the magnesium chloride alcoholate dropwise to a suspension of 0.5 g of MnCl2 in 20 mL of decane. React at 60°C for 4 hours to obtain a magnesium complex.

[0065] ② The magnesium complex described in step ① was added dropwise to 200 mL of titanium tetrachloride at -20°C over a 1-hour period, followed by a constant temperature reaction at -20°C for 1.0 hour. The temperature was then slowly raised to 120°C, and 0.2 mL of diisobutyl phthalate (the molar ratio of diisobutyl phthalate to magnesium in the magnesium complex was 0.15:1) was added. The reaction was then continued at 120°C for 1.5 hours. After the reaction was complete, the liquid was filtered, and 240 mL of titanium tetrachloride was added again, followed by a constant temperature reaction at 120°C for 2.0 hours. Finally, the catalyst was washed five times with hexane and dried to obtain an olefin polymerization catalyst, designated A3. Testing revealed a Ti content of 1.8% by weight and a magnesium content of 16% by weight.

[0066] Wherein, the particle size of MnCl2 in step ① is 0.5 to 1.0 microns.

[0067] (2) Catalytic propylene polymerization:

[0068] Under vacuum, 1000 g of liquid propylene monomer was added to a reactor. Then, at 30°C, 0.25 mol of triethylaluminum, 20 mg of olefin polymerization catalyst A3, and 0.2 g of hydrogen were added sequentially. The reaction temperature was then raised to 70°C and the reaction was allowed to proceed for 0.1 hour. 110 g of polymer was obtained with a polymerization activity of 26.3 kg / gTi. Testing revealed a bulk density of 0.21 g / mL.

[0069] Under vacuum, 1000 g of liquid propylene monomer was added to a reactor. Then, at 30°C, 0.25 mol of triethylaluminum, 20 mg of olefin polymerization catalyst A3, and 0.2 g of hydrogen were added sequentially. The reaction temperature was then raised to 70°C and the reaction was allowed to proceed for 1 hour. 700 g of polymer was obtained with a polymerization activity of 1675 kg / gTi. Testing revealed a bulk density of 0.31 g / mL.

[0070] Under vacuum, 1000 g of liquid propylene monomer was added to a reactor. Then, at 30°C, 0.25 mol of triethylaluminum, 20 mg of olefin polymerization catalyst A3, and 0.2 g of hydrogen were added sequentially. The reaction temperature was then raised to 70°C and the reaction was allowed to proceed for 2 hours. 850 g of polymer was obtained with a polymerization activity of 2034 kg / gTi. Testing revealed a bulk density of 0.33 g / mL.

[0071] Example 4

[0072] This embodiment is used to illustrate the olefin polymerization catalyst and its preparation method, as well as the polyolefin resin composition and its preparation method provided by the present invention.

[0073] (1) Preparation method of olefin polymerization catalyst:

[0074] ① Disperse 4.0 g of anhydrous magnesium chloride (MgCl2) and 13.0 mL of isooctyl alcohol in 90 mL of decane. Heat to 130°C to form a transparent solution. React at 130°C for 1 hour to obtain a magnesium chloride alcoholate. Then, add the magnesium chloride alcoholate dropwise to a suspension of 1.0 g of MnCl2 in 20 mL of decane. React at 60°C for 4 hours to obtain a magnesium complex.

[0075] ② The magnesium complex described in step ① was added dropwise to 200 mL of titanium tetrachloride at -20°C over a period of 1 hour, followed by a constant temperature reaction at -20°C for 1.0 hour. The temperature was then slowly raised to 120°C, and 0.4 mL of diisobutyl phthalate (the molar ratio of diisobutyl phthalate to magnesium in the magnesium complex was 0.15:1) was added. The reaction was then continued at 120°C for 1.5 hours. After the reaction was complete, the liquid was filtered, and 240 mL of titanium tetrachloride was added again. The reaction was continued at 120°C for 2.0 hours. Finally, the catalyst was washed five times with hexane and dried to obtain an olefin polymerization catalyst, designated A4. Testing revealed a Ti content of 1.2% by weight and a magnesium content of 12% by weight.

[0076] Wherein, the particle size of MnCl2 in step ① is 0.5 to 1.0 microns.

[0077] (2) Catalytic propylene polymerization:

[0078] Under vacuum, 1000 g of liquid propylene monomer was added to a reactor. Then, at 30°C, 0.25 mol of triethylaluminum, 20 mg of olefin polymerization catalyst A4, and 0.2 g of hydrogen were added sequentially. The reaction temperature was then raised to 70°C and the reaction was allowed to proceed for 0.1 hour. 120 g of polymer was obtained with a polymerization activity of 24.0 kg / gTi. Testing revealed a bulk density of 0.24 g / mL.

[0079] Under vacuum, 1000 g of liquid propylene monomer was added to a reactor. Then, at 30°C, 0.25 mol of triethylaluminum, 20 mg of olefin polymerization catalyst A4, and 0.2 g of hydrogen were added sequentially. The reaction temperature was then raised to 70°C and the reaction was allowed to proceed for 1 hour. 680 g of polymer was obtained with a polymerization activity of 136.0 kg / gTi. Testing revealed a bulk density of 0.32 g / mL.

[0080] Under vacuum, 1000 g of liquid propylene monomer was added to a reactor. Then, at 30°C, 0.25 mol of triethylaluminum, 20 mg of olefin polymerization catalyst A3, and 0.2 g of hydrogen were added sequentially. The reaction temperature was then raised to 70°C and the reaction was allowed to proceed for 2 hours. 840 g of polymer was obtained with a polymerization activity of 168.0 kg / gTi. Testing revealed a bulk density of 0.33 g / mL.

[0081] Example 5

[0082] This embodiment is used to illustrate the olefin polymerization catalyst and its preparation method, as well as the polyolefin resin composition and its preparation method provided by the present invention.

[0083] (1) Preparation method of olefin polymerization catalyst:

[0084] ① Disperse 4.0 g of anhydrous magnesium chloride (MgCl2) and 13.0 mL of isooctyl alcohol in 90 mL of decane. Heat to 130°C to form a transparent solution. React at 130°C for 1 hour to obtain a magnesium chloride alcoholate. Then, add the magnesium chloride alcoholate dropwise to a suspension of 1.0 g of MnCl2 in 20 mL of decane. React at 60°C for 4 hours to obtain a magnesium complex.

[0085] ② The magnesium complex described in step ① was added dropwise to 100 mL of titanium tetrachloride at -20°C over a period of 1 hour, followed by a constant temperature reaction at -20°C for 1.0 hour. The temperature was then slowly raised to 120°C, and 0.2 mL of di-n-butyl phthalate (the molar ratio of di-n-butyl phthalate to magnesium in the magnesium complex was 0.15:1) was added. The reaction was then continued at 120°C for 1.5 hours. After the reaction was complete, the liquid was filtered off, and 400 mL of titanium tetrachloride was added again. The reaction was continued at 120°C for 2.0 hours. Finally, the catalyst was washed five times with hexane and dried to obtain an olefin polymerization catalyst, designated A5. Testing revealed a Ti content of 1.0% by weight and a magnesium content of 10% by weight.

[0086] Wherein, the particle size of MnCl2 in step ① is 0.5 to 1.0 microns.

[0087] (2) Catalytic propylene polymerization:

[0088] Under vacuum, 1000 g of liquid propylene monomer was added to a reactor. Then, at 30°C, 0.25 mol of triethylaluminum, 20 mg of olefin polymerization catalyst A5, and 0.2 g of hydrogen were added sequentially. The reaction temperature was then raised to 70°C and the reaction was allowed to proceed for 0.1 hour. 120 g of polymer was obtained with a polymerization activity of 24.0 kg / gTi. Testing revealed a bulk density of 0.22 g / mL.

[0089] Under vacuum, 1000 g of liquid propylene monomer was added to a reactor. Then, at 30°C, 0.25 mol of triethylaluminum, 20 mg of olefin polymerization catalyst A5, and 0.2 g of hydrogen were added sequentially. The reaction temperature was then raised to 70°C and the reaction was allowed to proceed for 1 hour. 690 g of polymer was obtained with a polymerization activity of 138.0 kg / gTi. Testing revealed a bulk density of 0.30 g / mL.

[0090] Under vacuum, 1000 g of liquid propylene monomer was added to a reactor. Then, at 30°C, 0.25 mol of triethylaluminum, 20 mg of olefin polymerization catalyst A5, and 0.2 g of hydrogen were added sequentially. The reaction temperature was then raised to 70°C and the reaction was allowed to proceed for 2 hours. 835 g of polymer was obtained with a polymerization activity of 167.0 kg / gTi. Testing revealed a bulk density of 0.33 g / mL.

[0091] Application Example 1

[0092] This application example is used to illustrate the application of the olefin polymerization catalyst provided by the present invention in the synthesis of polypropylene thermoplastic elastomer.

[0093] Under vacuum, 450 grams of liquid propylene monomer was added to a reactor. 0.25 mol of triethylaluminum, 20 mg of olefin polymerization catalyst A3, and 0.1 g of hydrogen were then added sequentially at 30°C. The reaction temperature was then raised to 75°C for 0.2 hours. The remaining propylene monomer in the reactor was then evacuated and the temperature was lowered to 50°C. A mixture of ethylene and propylene was then continuously introduced into the reactor, with a mass ratio of 1:1.5. The reaction was completed when the final ethylene / propylene mixture consumption reached 250 grams, yielding 490 grams of polymer. The polymer contained 51% ethylene-propylene rubber by mass. The polymer particles exhibited good fluidity and showed no clumping.

[0094] Application Example 2

[0095] This application example is used to illustrate the application of the olefin polymerization catalyst provided by the present invention in the synthesis of polypropylene thermoplastic elastomer.

[0096] Under vacuum, 450 grams of liquid propylene monomer was added to a reactor. 0.25 mol of triethylaluminum, 20 mg of olefin polymerization catalyst A3, and 0.05 g of hydrogen were then added sequentially at 30°C. The reaction temperature was then raised to 75°C for 0.2 hours. The remaining propylene monomer in the reactor was then evacuated and the temperature was lowered to 50°C. A mixture of ethylene and propylene was then continuously introduced into the reactor, with a mass ratio of 1:1.5. The reaction was completed when 450 grams of the mixture was consumed, yielding 662 grams of polymer. The polymer contained 68% ethylene-propylene rubber by mass. The polymer particles exhibited good fluidity and showed no clumping.

Claims

1. A method for increasing the porosity and rubber content of a polypropylene thermoplastic elastomer, characterized in that: The method comprises adding an olefin polymerization catalyst during the catalytic propylene polymerization reaction, wherein the olefin polymerization catalyst comprises a metal chloride, a transition metal component and a non-transition metal component; the transition metal component is titanium tetrahalide and / or titanium alkoxide, and the non-transition metal component is a magnesium-containing compound; and the metal chloride is selected from at least one of FeCl2, ZnCl2, CuCl2, PdCl2 and MnCl2; Based on the total weight of the olefin polymerization catalyst, the content of the metal chloride is 0.5-50% by weight, and the total content of the metal elements in the transition metal component and the non-transition metal component is 2-80% by weight; The titanium tetrahalide is at least one of TiCl4, TiBr4 and TiI4; The general formula of the titanium alkoxide is R 4 p Ti(OR 5 ) 4-p , R 4 and R 5 Each is independently a C1-C4 alkyl group, and p is an integer from 0 to 3; The magnesium-containing compound is of the general formula MgX 1 2 magnesium halide and / or general formula RMgX 2 Grignard reagent; in MgX 1 2 in, X 1 is F, Cl, Br or I; in RMgX 2 In the example, R is C1-C 10 The alkyl group, X 2 is F, Cl, Br or I.

2. The method according to claim 1, characterized in that Based on the total weight of the olefin polymerization catalyst, the content of the metal chloride is 5-20 wt %, and the total content of the metal elements in the transition metal component and the non-transition metal component is 10-20 wt %.

3. The method according to claim 1, characterized in that Based on the total weight of the olefin polymerization catalyst, the content of the transition metal element in the transition metal component is 0.5-10% by weight, and the content of the non-transition metal element in the non-transition metal component is 2-30% by weight; the particle size of the metal chloride is 0.05-1.0 micron.

4. The method according to claim 1, wherein The alkoxytitanium is at least one of tetrabutyl titanate, methyltriethoxytitanium, methyltrimethoxytitanium and tetraethyl titanate.

5. The method according to claim 1, wherein The olefin polymerization catalyst further comprises an internal electron donor compound and a cocatalyst; the internal electron donor compound is a diether compound and / or a carboxylate compound; the cocatalyst is an alkyl aluminum, and its general formula is Al(OR′) q R′′ 3-q , R′ and R′′ are each independently C2-C 10 alkyl, 0≤q≤3.

6. The method according to claim 1, characterized in that The preparation method of the olefin polymerization catalyst comprises the following steps: (1) reacting a metal chloride with a magnesium-containing compound at 30-150° C. for 1-50 hours to obtain a magnesium complex; (2) reacting the magnesium complex with a transition metal component to obtain an olefin polymerization catalyst.

7. The method according to claim 6, characterized in that In step (1), the weight ratio of the metal chloride to the non-transition metal component is 1:0.5-99; in step (2), the mass ratio of the magnesium complex to the transition metal component is 1:1-100.

8. The method according to claim 6, characterized in that In step (1), the weight ratio of the metal chloride to the non-transition metal component is 1:0.5-50.

9. The method according to claim 6, characterized in that The reaction method is as follows: first, the magnesium complex is mixed with a portion of titanium tetrahalide and / or a portion of titanium alkoxide and reacted at -20-20°C for 0.5-2 hours, then the temperature is raised to 80-130°C for reaction for 1-4 hours, then the reaction product is separated into solid and liquid, and the obtained solid product is reacted with the remaining portion of titanium tetrahalide and / or the remaining portion of titanium alkoxide at 80-130°C for 1-4 hours.

10. The method according to claim 9, characterized in that The part of the alkoxy titanium and the remaining part of the alkoxy titanium are each independently at least one of Ti(OEt)Cl3, Ti(OEt)2Cl2, Ti(OEt)3Cl, Ti(OEt)4 and Ti(OBu)4; the mass ratio of the part of the titanium tetrahalide and the remaining part of the titanium tetrahalide is 1:0.1~10.

11. The method according to claim 6, characterized in that The preparation method further includes adding an internal electron donor compound. The internal electron donor compound is added in the following manner: after reacting the magnesium complex with a portion of the transition metal component at -20-20°C for 0.5-2 hours, the internal electron donor compound is added to the reaction system.