Olefin polymerization catalyst and method for preparing the same

Abstract

The application discloses an olefin polymerization catalyst and a preparation method thereof, and the olefin polymerization catalyst is used for preparing a polypropylene thermoplastic elastomer, and the olefin polymerization catalyst contains silicon tetrachloride modified silicon dioxide, a transition metal component and a non-transition metal component; the transition metal component is titanium tetrachloride and / or titanium alkoxy, and the non-transition metal component is a magnesium-containing compound. The olefin polymerization catalyst has high initial activity and overall activity, and polypropylene particles with high porosity are obtained. The catalyst can obtain a polypropylene thermoplastic elastomer with high rubber content in the synthesis process of the polypropylene thermoplastic elastomer.

Description

TECHNICAL FIELD

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

[0002] In order to improve the poor low-temperature toughness of polypropylene, introducing a rubber component with excellent impact toughness is an effective method. Especially, in the polymerization process, a continuous polymerization method is adopted, and a propylene homopolymerization reaction and an ethylene / propylene copolymerization reaction are sequentially performed, so that a heterophasic copolymer polypropylene (impact copolymer polypropylene) is obtained, which has been widely used in the fields of automobiles, household appliances and the like. Further increasing the rubber content in the heterophasic copolymer polypropylene can greatly improve the performance of the heterophasic copolymer polypropylene, and a polypropylene thermoplastic elastomer is obtained. However, it is difficult to realize the synthesis of a heterophasic copolymer polypropylene with a rubber mass percentage of greater than 35% on most existing process devices. The main reason is that when the rubber content is high, the rubber migrates to the surface of the polymer particles, which leads to easy adhesion between the polymer particles and between the polymer particles and the reactor, affects the transportation of the polymer, and there is a risk of reactor blockage. In order to solve the above problems, improvement of the catalyst and the polymerization process are two main ways. 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 are both beneficial to increasing the rubber content in the heterophasic copolymer polypropylene, and obtaining a polypropylene thermoplastic elastomer with high rubber content.

[0003] Olefin polymerization catalysts have always been one of the main driving forces for promoting the progress of polyolefin technology and upgrading the performance of products. The composition and preparation method of the catalyst can affect the olefin polymerization activity and kinetic behavior, and thus change the particle properties such as porosity of the polymer particles. It has been reported (Highly efficient FeCl3 doped Mg(OEt)2 / TiCl4-based Ziegler–Natta catalysts for ethylene polymerization. Designed Monomers and Polymers, 2015, 18(7), 599-610) that doping FeCl3 and SiCl4 into the catalyst Mg(OEt)2 / TiCl4 can increase the ethylene polymerization activity by 2.4 times, increase the weight average molecular weight and particle bulk density of polyethylene, and reduce the content of low molecular weight components. SUMMARY

[0004] The present application aims to provide an olefin polymerization catalyst and a preparation method thereof, so as to improve the initial activity and overall activity of the catalyst and obtain polypropylene particles with high porosity. The catalyst can be used to obtain a polypropylene thermoplastic elastomer with high rubber content in the synthesis of the polypropylene thermoplastic elastomer.

[0005] To achieve the above-mentioned purpose, the present application provides an olefin polymerization catalyst for preparing a polypropylene thermoplastic elastomer, the olefin polymerization catalyst comprising silicon tetrachloride modified silicon dioxide, a transition metal component and a non-transition metal component; the transition metal component is titanium tetrachloride and / or titanium alkoxide, and the non-transition metal component is a magnesium-containing compound.

[0006] The preparation method of the silicon tetrachloride modified silicon dioxide in the olefin polymerization catalyst of the present application specifically comprises the following steps: dispersing silicon dioxide in a solvent to obtain a dispersion solution of silicon dioxide; at room temperature, silicon tetrachloride is added dropwise into the dispersion solution of silicon dioxide, and after the dropwise addition is completed, the reaction is continued for 2-24 hours; after the reaction is completed, filtration and drying are performed to obtain silicon tetrachloride modified silicon dioxide.

[0007] The solvent in the olefin polymerization catalyst of the present application is a C5-C 10 alkane; the concentration of the silicon dioxide in the solvent is 0.05-100 g / L; and the mass ratio of the silicon tetrachloride to the silicon dioxide is 0.1-100:1.

[0008] In the olefin polymerization catalyst of the present application, the content of the silicon tetrachloride modified silicon dioxide 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, based on the total weight of the olefin polymerization catalyst.

[0009] Preferably, the content of the silicon tetrachloride modified silicon dioxide is 5-20% by weight, and the total content of the metal elements in the transition metal component and the non-transition metal component is 10-20% by weight, based on the total weight of the olefin polymerization catalyst.

[0010] In the olefin polymerization catalyst of the present application, 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, based on the total weight of the olefin polymerization catalyst.

[0011] In the olefin polymerization catalyst of the present application, the titanium tetrachloride is at least one of TiCl4, TiBr4 and TiI4.

[0012] In the olefin polymerization catalyst of the present application, the general formula of the titanium alkoxide is R 4 p Ti(OR5 ) 4-p , R 4 and R 5 each independently is C1-C4 alkyl, and p is an integer of 0-3; preferably, the titanium alkoxide is at least one of tetrabutyl titanate, methyl triethoxy titanium, methyl trimethoxy titanium and tetraethyl titanate.

[0013] The olefin polymerization catalyst of the present application, the magnesium-containing compound is a magnesium halide of general formula MgX 1 2 and / or a Grignard reagent of general formula RMgX 2 ; in MgX 1 2, X 1 is F, Cl, Br or I; in RMgX 2 , R is C1-C 10 alkyl and X 2 is F, Cl, Br or I.

[0014] The olefin polymerization catalyst of the present application, the olefin polymerization catalyst further contains an internal electron donor compound; preferably, the internal electron donor compound is a diether compound and / or a carboxylate compound.

[0015] The olefin polymerization catalyst of the present application, a cocatalyst is further added, the cocatalyst is an alkyl aluminum, the cocatalyst is of general formula Al(OR′) q R″ 3-q , R′ and R″ each independently is C2-C 10 alkyl, and 0≤q≤3.

[0016] The present application further provides a preparation method of an olefin polymerization catalyst, the preparation method comprises the following steps:

[0017] (1) reacting silicon tetrachloride modified silica with a magnesium-containing compound of non-transition metal component at 30-150℃ for 1-50 hours to obtain a magnesium complex;

[0018] (2) reacting the magnesium complex with a titanium tetrahalide of transition metal component and / or a titanium alkoxide to obtain an olefin polymerization catalyst.

[0019] The preparation method of the olefin polymerization catalyst of the present application, in step (1), the weight ratio of the silicon tetrachloride modified silica to the magnesium-containing compound of non-transition metal component is 1:0.5-99, preferably 1:0.5-50.

[0020] The preparation method of the olefin polymerization catalyst of the present application is as follows: first, the magnesium compound of the silicon tetrachloride modified silica is mixed with a part of titanium tetrachloride and / or a part of titanium alkoxide and reacted at -20 to 0°C for 0.5 to 2 hours, then the temperature is raised to 80 to 130°C and reacted for 1 to 4 hours, then the reaction product is separated into solid and liquid, and the obtained solid product is mixed with the remaining part of titanium tetrachloride and / or the remaining part of titanium alkoxide and reacted at 80 to 130°C for 1 to 4 hours.

[0021] The preparation method of the olefin polymerization catalyst of the present application, wherein the part of titanium alkoxide and the remaining part of titanium alkoxide are each independently at least one of Ti(OEt)Cl3, Ti(OEt)2Cl2, Ti(OEt)3Cl, Ti(OEt)4 and Ti(OBu)4.

[0022] The preparation method of the olefin polymerization catalyst of the present application, wherein the mass ratio of the part of titanium tetrachloride and the remaining part of titanium tetrachloride is 1:0.1 to 10.

[0023] The preparation method of the olefin polymerization catalyst of the present application, wherein an internal electron donor compound is further added in the preparation method, and the internal electron donor compound is added to the reaction system after the magnesium compound is reacted with the part of titanium tetrachloride and / or the part of titanium alkoxide at -20 to 0°C for 0.5 to 2 hours and before the reaction at 80 to 130°C for 1 to 4 hours.

[0024] The preparation method of the olefin polymerization catalyst of the present application, wherein the mass ratio of the magnesium compound and the transition metal component is 1:1 to 100.

[0025] The olefin polymerization catalyst of the present application is used in the olefin polymerization reaction, and the polypropylene nascent particles with high porosity can be obtained, the problem of low efficiency in subsequent ethylene-propylene copolymerization is solved, and the polypropylene thermoplastic elastomer with high rubber content can be finally synthesized. The olefin polymerization catalyst of the present application has high initial activity, and can generate more pores in the polymer without breaking the polymer, and the polypropylene particles obtained have low bulk density (<0.35 g / mL, which is significantly lower than 0.42 g / mL of ordinary polypropylene) and high porosity. In the subsequent ethylene-propylene copolymerization process, the diffusion of monomers and the filling of rubber both provide more "channels", thereby providing conditions for the preparation of the polypropylene thermoplastic elastomer particles with high rubber content and good particle morphology. The use effect of the olefin polymerization catalyst is also verified by a large number of experimental results, and the polypropylene thermoplastic elastomer with rubber mass percentage content of more than 50% or even close to 70% is synthesized. The olefin polymerization catalyst of the present application breaks through the bottleneck of low rubber content and polymer particle sticking in the polypropylene kettle alloy production process, and can synthesize the polypropylene thermoplastic elastomer with high rubber content in the kettle, which has great industrial application prospect. DETAILED DESCRIPTION

[0026] The present application will be further described below in conjunction with examples. These examples are only used to illustrate the present application and not used to limit the scope of the present application. The experimental methods not specified in the following example are generally carried out according to the conventional conditions in the art or according to the conditions recommended by the manufacturers; the raw materials, reagents and the like used, if not specifically stated, are all raw materials and reagents that can be obtained through commercial channels. Any non-essential changes and substitutions made by those skilled in the art on the basis of the present application shall fall within the scope of the present application.

[0027] Evaluation and analysis method:

[0028] The content of the transition metal element in the olefin polymerization catalyst is determined by ultraviolet spectrophotometry.

[0029] The content of magnesium element in the olefin polymerization catalyst is determined by titration, specifically as follows: 50 mg of the catalyst is dissolved in 10 mL of sulfuric acid solution under nitrogen protection, heated to boiling for 10 minutes, then filtered to remove the insoluble substances, and then titrated with EDTA with a concentration of 0.01 mol·L -1 Chrome black T is used as an indicator during titration, and when the color of the solution containing the catalyst changes to blue-violet, the titration end point is reached, the amount of EDTA used in the entire titration process is V (mL), and the content of magnesium element = (0.01 x V ÷ 10) x 24.3 ÷ (50 x 10-3).

[0030] The content of titanium element in the olefin polymerization catalyst is measured by a spectrophotometer, specifically as follows: 50 mg of the catalyst is dissolved in 10 mL of sulfuric acid solution under nitrogen protection, heated to boiling for 10 minutes, then filtered to remove insoluble substances, then the absorbance of the solution at a fixed wavelength (410 nm) is measured by a spectrophotometer, and the concentration of titanium or zirconium element is obtained by comparison with the standard curve at 410 nm, and then the content of titanium element in the olefin polymerization catalyst is calculated.

[0031] The rubber content in the application example is determined according to the ratio between the absorbed ethylene-propylene mixed gas mass and the total mass of the polymer.

[0032] Example 1

[0033] This example is used to illustrate the olefin polymerization catalyst and the preparation method thereof, and the polyolefin resin composition and the preparation method thereof provided by the present application.

[0034] (1) Modification of silicon dioxide

[0035] 10 g of silicon dioxide with a particle size of 20 nm is dispersed in 100 mL of heptane, then 5 g of silicon tetrachloride is added dropwise to the above solution, after the dropwise addition is completed, the reaction is continued for 10 hours, after the reaction is completed, filtration and drying are performed to obtain 12 g of silicon tetrachloride modified silicon dioxide.

[0036] (2) Preparation method of the olefin polymerization catalyst:

[0037] ① 4.0 g of anhydrous magnesium chloride MgCl2 is dispersed in 13.0 mL of isooctanol in 90 mL of decane, heated to 130°C to form a transparent solution, and reacted at 130°C for 1.0 hour to obtain a magnesium chloride alcohol complex. Then the above magnesium chloride alcohol complex is added dropwise to a suspension of 1.0 g of silicon tetrachloride modified silicon dioxide and 20 mL of decane, and reacted at 60°C for 4.0 hours to obtain a magnesium complex.

[0038] ② The magnesium complex described in step ① is added dropwise to 200 mL of titanium tetrachloride at -20°C, and the dropwise addition time is 1 hour, then the temperature is kept at -20°C for 1.0 hour. Then slowly warmed to 120°C, 0.2 mL of diisobutyl phthalate (the molar ratio of diisobutyl phthalate to magnesium element in the magnesium complex is 0.15:1) is added, and then reacted at 120°C for 1.5 hours. After the reaction is completed, the liquid is filtered out, 240 mL of titanium tetrachloride is added again, and reacted at 120°C for 2.0 hours. Finally, washed with hexane for 5 times, and dried to obtain an olefin polymerization catalyst, marked as A1. The mass percentage content of the transition metal element Ti is 2.5%, and the mass percentage content of the metal element magnesium is 15%.

[0039] (3) Catalytic propylene polymerization reaction:

[0040] In a vacuum state, 1000 grams of liquid propylene monomer was added into the reactor, then 0.25 mol triethylaluminum, 20 mg of olefin polymerization catalyst Al and 0.2 g of hydrogen were added in turn at 30°C, and then the reaction temperature was raised to 70°C for 0.1 hour. 80 g of polymer was obtained, and the polymerization activity was 24 kg / g Ti. The polymer particle bulk density was 0.25 g / mL.

[0041] In a vacuum state, 1000 grams of liquid propylene monomer was added into the reactor, then 0.25 mol triethylaluminum, 20 mg of olefin polymerization catalyst Al and 0.2 g of hydrogen were added in turn at 30°C, and then the reaction temperature was raised to 70°C for 1.0 hour. 500 g of polymer was obtained, and the polymerization activity was 1197 kg / g Ti. The polymer particle bulk density was 0.32 g / mL.

[0042] In a vacuum state, 1000 grams of liquid propylene monomer was added into the reactor, then 0.25 mol triethylaluminum, 20 mg of olefin polymerization catalyst Al and 0.2 g of hydrogen were added in turn at 30°C, and then the reaction temperature was raised to 70°C for 2.0 hour. 750 g of polymer was obtained, and the polymerization activity was 1795 kg / g Ti. The polymer particle bulk density was 0.34 g / mL.

[0043] Comparative Example 1

[0044] This comparative example is used to illustrate a reference olefin polymerization catalyst and its preparation method and catalyze propylene polymerization reaction.

[0045] The olefin polymerization catalyst and polyolefin resin composition were prepared according to the method of Example 1, except that in this comparative example, no silicon tetrachloride modified silicon dioxide was added in the preparation process of the olefin polymerization catalyst, and the specific steps were as follows:

[0046] (1) Preparation method of the olefin polymerization catalyst:

[0047] ① 4.0 g of anhydrous magnesium chloride MgCl2 was dispersed in 13.0 mL of isooctanol in 90 mL of decane, heated to 130°C to form a transparent solution, and reacted at 130°C for 1.0 hour to obtain a magnesium chloride alcohol complex.

[0048] 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, and then reacted at -20°C for 1.0 hour. Next, the temperature was 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 carried out at 120°C for 1.5 hours. After the reaction was complete, the liquid was filtered off, and another 240 mL of titanium tetrachloride was added. The reaction was then carried out at 120°C for 2.0 hours. Finally, the mixture was washed five times with hexane and dried to obtain the olefin polymerization catalyst, designated B1. The mass percentage of transition metal Ti was 2.3%, and the mass percentage of magnesium was 18%.

[0049] (2) Catalytic polymerization of propylene:

[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 carried out for 0.1 hours. 60 g of polymer was obtained, with 14.4 kg / g Ti as the polymerization active sites. The bulk density of the polymer particles was measured to be 0.35 g / mL.

[0051] 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 carried out for 1.0 hour. 400 g of polymer was obtained, with a polymerization activity of 957.4 kg / g Ti. The bulk density of the polymer particles was measured to be 0.42 g / mL.

[0052] 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 carried out for 2.0 hours. 650 g of polymer was obtained, with a polymerization activity of 1556 kg / g Ti. The bulk density of the polymer particles was measured to be 0.43 g / mL.

[0053] Example 2

[0054] This embodiment illustrates the olefin polymerization catalyst and its preparation method provided by the present invention, as well as the polyolefin resin composition and its preparation method.

[0055] (1) Modification of silica

[0056] Take 10 g of silica, particle size of 40 nm, dispersed in 100 mL of heptane, then add 1 g of silicon tetrachloride to the above solution, after the dropwise addition is completed, continue to react for 20 hours, after the reaction is completed, filter and dry to obtain 10.5 g of silicon tetrachloride modified silica.

[0057] (2) Preparation method of olefin polymerization catalyst:

[0058] ① 4.0 g of anhydrous magnesium chloride MgCl2 is dispersed in 13.0 mL of isooctanol in 90 mL of decane, heated to 130°C to form a transparent solution, and reacted at 130°C for 1.0 hour to obtain a magnesium chloride alcohol complex. Then, the above magnesium chloride alcohol complex is added dropwise to a suspension of 1.0 g of silicon tetrachloride modified silica and 20 mL of decane, and reacted at 60°C for 4.0 hours to obtain a magnesium complex.

[0059] ② The magnesium complex described in step ① is added dropwise to 200 mL of titanium tetrachloride at 0°C, the dropwise addition time is 1 hour, then the temperature is kept at -20°C for 1.0 hour. Then slowly warm up to 120°C, add 0.2 mL of diisobutyl phthalate (the molar ratio of diisobutyl phthalate to magnesium in the magnesium complex is 0.15:1), then keep the temperature at 120°C for 1.5 hours, after the reaction is completed, filter out the liquid, add 240 mL of titanium tetrachloride again, and keep the temperature at 120°C for 2.0 hours. Finally, wash with hexane for 5 times, and dry to obtain an olefin polymerization catalyst, marked as A2. The mass percentage of transition metal element Ti is 2.3%, and the mass percentage of metal element magnesium is 18%.

[0060] (3) Catalytic propylene polymerization reaction:

[0061] Under vacuum, 1000 grams of liquid propylene monomer is added to the reaction kettle, then 0.25 mol of triethylaluminum, 20 milligrams of olefin polymerization catalyst A2 and 0.2 g of hydrogen are added in turn at 30°C, then the reaction temperature is raised to 70°C and reacted for 0.1 hour. 90 g of polymer is obtained, and the polymerization activity is 14.4 kg / g Ti. The polymer particle bulk density is 0.25 g / mL.

[0062] Under vacuum, 1000 grams of liquid propylene monomer is added to the reaction kettle, then 0.25 mol of triethylaluminum, 20 milligrams of olefin polymerization catalyst A2 and 0.2 g of hydrogen are added in turn at 30°C, then the reaction temperature is raised to 70°C and reacted for 1.0 hour. 650 g of polymer is obtained, and the polymerization activity is 1590 kg / g Ti. The polymer particle bulk density is 0.32 g / mL.

[0063] In a vacuum state, 1000 g of liquid propylene monomer was added into a reaction kettle, then 0.25 mol of triethylaluminum, 20 mg of the olefin polymerization catalyst A2 and 0.2 g of hydrogen were added in turn at 30°C, and then the reaction temperature was raised to 70°C for 2.0 hours. 820 g of polymer was obtained, and the polymerization activity was 1962 kg / g Ti. It was detected that the bulk density of the polymer particles was 0.34 g / mL.

[0064] Example 3

[0065] This example is used to illustrate the olefin polymerization catalyst and the preparation method thereof and the polyolefin resin composition and the preparation method thereof provided by the present application.

[0066] (1) Modification of silicon dioxide

[0067] 10 g of silicon dioxide with a particle size of 80 nm was dispersed in 100 mL of heptane, and then 20 g of silicon tetrachloride was added dropwise to the above solution. After the dropwise addition was completed, the reaction was continued for 2 hours. After the reaction was completed, filtration and drying were performed to obtain 10.3 g of silicon tetrachloride-modified silicon dioxide.

[0068] (2) Preparation method of the olefin polymerization catalyst:

[0069] ① 4.0 g of anhydrous magnesium chloride MgCl2 was dispersed in 13.0 mL of isooctanol in 90 mL of decane, heated to 130°C to form a transparent solution, and reacted at 130°C for 1.0 hour to obtain a magnesium alcoholate. Then the magnesium alcoholate was added dropwise to a suspension of 2.0 g of silicon tetrachloride-modified silicon dioxide and 20 mL of decane, and reacted at 60°C for 4.0 hours to obtain a magnesium complex.

[0070] ② The magnesium complex described in step ① was added dropwise to 200 mL of titanium tetrachloride at 10°C, and the dropwise addition was completed in 1 hour. Then the temperature was kept at -20°C for 1.0 hour. Subsequently, the temperature was slowly raised to 120°C, and 0.2 mL of diisobutyl phthalate was added (the molar ratio of diisobutyl phthalate to magnesium in the magnesium complex was 0.15:1), and then the temperature was kept at 120°C for 1.5 hours. After the reaction was completed, the liquid was filtered out, and 240 mL of titanium tetrachloride was added again, and the temperature was kept at 120°C for 2.0 hours. Finally, the catalyst was washed with hexane for 5 times, and dried to obtain an olefin polymerization catalyst, which was recorded as A3. It was detected that the mass percentage of the transition metal element Ti was 2.1%, and the mass percentage of the metal element magnesium was 17%.

[0071] (3) Catalytic propylene polymerization reaction:

[0072] In a vacuum state, 1000 g of liquid propylene monomer was added into a reaction kettle, then 0.25 mol of triethylaluminum, 20 mg of olefin polymerization catalyst A3 and 0.2 g of hydrogen were sequentially added at 30°C, and then the reaction temperature was raised to 70°C for 0.1 hour. 88 g of polymer was obtained, and the polymerization activity was 14.2 kg / g Ti. The polymer particle bulk density was 0.25 g / mL.

[0073] In a vacuum state, 1000 g of liquid propylene monomer was added into a reaction kettle, then 0.25 mol of triethylaluminum, 20 mg of olefin polymerization catalyst A3 and 0.2 g of hydrogen were sequentially added at 30°C, and then the reaction temperature was raised to 70°C for 1.0 hour. 650 g of polymer was obtained, and the polymerization activity was 1500 kg / g Ti. The polymer particle bulk density was 0.32 g / mL.

[0074] In a vacuum state, 1000 g of liquid propylene monomer was added into a reaction kettle, then 0.25 mol of triethylaluminum, 20 mg of olefin polymerization catalyst A3 and 0.2 g of hydrogen were sequentially added at 30°C, and then the reaction temperature was raised to 70°C for 2.0 hour. 815 g of polymer was obtained, and the polymerization activity was 1900 kg / g Ti. The polymer particle bulk density was 0.34 g / mL.

[0075] Example 4

[0076] This example is used to illustrate the olefin polymerization catalyst provided by the present application and the preparation method thereof, and the polyolefin resin composition and the preparation method thereof.

[0077] (1) Modification of silicon dioxide

[0078] Take 10 g of silicon dioxide with a particle size of 20 nm, disperse it in 100 mL of heptane, then add 5 g of silicon tetrachloride to the above solution, after the addition is completed, continue to react for 10 hours, after the reaction is completed, filter and dry to obtain 12 g of silicon tetrachloride modified silicon dioxide.

[0079] (2) Preparation method of olefin polymerization catalyst:

[0080] ① 4.0 g of anhydrous magnesium chloride MgCl2 was dispersed in 13.0 mL of isooctanol in 90 mL of decane, heated to 130°C to form a transparent solution, and reacted at 130°C for 1.0 hour to obtain a magnesium chloride alcohol complex. Then the above magnesium chloride alcohol complex was added dropwise into a suspension of 0.5 g of silicon tetrachloride modified silicon dioxide and 20 mL of decane, and reacted at 60°C for 4.0 hours to obtain a magnesium complex.

[0081] (2) Preparation of the olefin polymerization catalyst: ① 1000 g of liquid propylene monomer was added into a reactor under vacuum, and then 0.25 mol of triethylaluminum and 20 mg of the magnesium complex prepared in Example 1 were added into the reactor under stirring at 30°C. After the addition, the reaction temperature was raised to 120°C, and 0.2 g of hydrogen was added into the reactor. Then, the reaction temperature was raised to 120°C and kept for 1.0 hour. After the reaction, the liquid was filtered out, and 240 mL of titanium tetrachloride was added into the reactor. The reaction was carried out at 120°C for 2.0 hours. Finally, the reactor was washed with hexane for 5 times, and the olefin polymerization catalyst was obtained after drying, which was recorded as A3. The mass percentage of the transition metal Ti was 2.3%, and the mass percentage of the metal magnesium was 14.8%.

[0082] (3) Catalytic polymerization of propylene:

[0083] Under vacuum, 1000 g of liquid propylene monomer was added into a reactor, and then 0.25 mol of triethylaluminum, 20 mg of the olefin polymerization catalyst A4 and 0.2 g of hydrogen were added into the reactor under stirring at 30°C. Then, the reaction temperature was raised to 70°C and kept for 0.1 hour. The polymer obtained was 82 g, and the polymerization activity was 24.2 kg / g Ti. The bulk density of the polymer particles was 0.24 g / mL.

[0084] Under vacuum, 1000 g of liquid propylene monomer was added into a reactor, and then 0.25 mol of triethylaluminum, 20 mg of the olefin polymerization catalyst A4 and 0.2 g of hydrogen were added into the reactor under stirring at 30°C. Then, the reaction temperature was raised to 70°C and kept for 1.0 hour. The polymer obtained was 510 g, and the polymerization activity was 1202 kg / g Ti. The bulk density of the polymer particles was 0.33 g / mL.

[0085] Under vacuum, 1000 g of liquid propylene monomer was added into a reactor, and then 0.25 mol of triethylaluminum, 20 mg of the olefin polymerization catalyst A4 and 0.2 g of hydrogen were added into the reactor under stirring at 30°C. Then, the reaction temperature was raised to 70°C and kept for 2.0 hour. The polymer obtained was 760 g, and the polymerization activity was 1820 kg / g Ti. The bulk density of the polymer particles was 0.33 g / mL.

[0086] Example 5

[0087] This example is used to illustrate the olefin polymerization catalyst and the preparation method thereof, and the polyolefin resin composition and the preparation method thereof provided by the present application.

[0088] (1) Modification of the silicon dioxide

[0089] Take 10 g of silica, particle size of 20 nm, dispersed in 100 mL of heptane, then add 5 g of silicon tetrachloride to the above solution, after the dropwise addition is completed, continue to react for 10 hours, after the reaction is completed, filter and dry to obtain 12 g of silicon tetrachloride modified silica.

[0090] (2) Preparation method of olefin polymerization catalyst:

[0091] ① 4.0 g of anhydrous magnesium chloride MgCl2 is dispersed in 13.0 mL of isooctanol in 90 mL of decane, heated to 130°C to form a transparent solution, and reacted at 130°C for 1.0 hour to obtain a magnesium chloride alcohol complex. Then, the above magnesium chloride alcohol complex is added dropwise to a suspension of 1.0 g of silicon tetrachloride modified silica and 20 mL of decane, and reacted at 80°C for 2.0 hours to obtain a magnesium complex.

[0092] ② The magnesium complex described in step ① is added dropwise to 200 mL of titanium tetrachloride at -20°C, and the dropwise addition takes 1 hour, then the temperature is kept at -20°C for 1.0 hour. Then slowly warm up to 120°C, add 0.4 mL of diisobutyl phthalate (the molar ratio of diisobutyl phthalate to magnesium in the magnesium complex is 0.3:1), then keep the temperature at 120°C for 1.5 hours. After the reaction is completed, filter out the liquid, add 240 mL of titanium tetrachloride again, and keep the temperature at 120°C for 2.0 hours. Finally, wash with hexane for 5 times, and dry to obtain an olefin polymerization catalyst, marked as A5. The mass percentage of transition metal element Ti is 2.0%, and the mass percentage of metal element magnesium is 16.0%.

[0093] (3) Catalytic propylene polymerization reaction:

[0094] Under vacuum, 1000 grams of liquid propylene monomer is added to the reaction kettle, then 0.25 mol of triethylaluminum, 20 milligrams of olefin polymerization catalyst A5 and 0.2 g of hydrogen are added in turn at 30°C, and then the reaction temperature is raised to 70°C for 0.1 hour. 70 g of polymer is obtained, and the polymerization activity is 20 kg / g Ti. The polymer particle bulk density is 0.26 g / mL.

[0095] Under vacuum, 1000 grams of liquid propylene monomer is added to the reaction kettle, then 0.25 mol of triethylaluminum, 20 milligrams of olefin polymerization catalyst A5 and 0.2 g of hydrogen are added in turn at 30°C, and then the reaction temperature is raised to 70°C for 1.0 hour. 480 g of polymer is obtained, and the polymerization activity is 1120 kg / g Ti. The polymer particle bulk density is 0.33 g / mL.

[0096] In a vacuum state, 1000 g of liquid propylene monomer was added into a reactor, then 0.25 mol of triethylaluminum, 20 mg of the olefin polymerization catalyst A5 and 0.2 g of hydrogen were added in turn at 30 °C, and then the reaction temperature was raised to 70 °C for 2.0 hours. 736 g of polymer was obtained, and the polymerization activity was 1700 kg / g Ti. It was detected that the bulk density of the polymer particles was 0.34 g / mL.

[0097] Example 6

[0098] This example is used to illustrate the olefin polymerization catalyst and the preparation method thereof, and the polyolefin resin composition and the preparation method thereof provided by the present application.

[0099] (1) Modification of silicon dioxide

[0100] 10 g of silicon dioxide with a particle size of 20 nm was dispersed in 100 mL of heptane, and then 5 g of silicon tetrachloride was added dropwise to the above solution. After the dropwise addition was completed, the reaction was continued for 2 hours. After the reaction was completed, filtration and drying were performed to obtain 11.6 g of silicon tetrachloride-modified silicon dioxide.

[0101] (2) Preparation method of the olefin polymerization catalyst:

[0102] ① 4.0 g of anhydrous magnesium chloride MgCl2 was dispersed in 13.0 mL of isooctanol in 90 mL of decane, heated to 130 °C to form a transparent solution, and reacted at 130 °C for 1.0 hour to obtain a magnesium alcoholate. Then the above magnesium alcoholate was added dropwise to a suspension of 1.0 g of silicon tetrachloride-modified silicon dioxide and 20 mL of decane, and reacted at 60 °C for 4.0 hours to obtain a magnesium complex.

[0103] ② The magnesium complex described in step ① was added dropwise to 200 mL of titanium tetrachloride at -20 °C, and the dropwise addition was completed in 1 hour. Then the temperature was kept at -20 °C for 1.0 hour. Then the temperature was slowly raised to 120 °C, and 0.2 mL of diisobutyl phthalate was added (the molar ratio of diisobutyl phthalate to magnesium in the magnesium complex was 0.15:1), and then the temperature was kept at 120 °C for 1.5 hours. After the reaction was completed, the liquid was filtered out, and then 240 mL of titanium tetrachloride was added again, and the temperature was kept at 120 °C for 2.0 hours. Finally, the catalyst was washed with hexane for 5 times, and then dried to obtain an olefin polymerization catalyst, which was recorded as A6. It was detected that the mass percentage of the transition metal element Ti was 2.4%, and the mass percentage of the metal element magnesium was 15.2%.

[0104] (3) Catalytic propylene polymerization reaction:

[0105] In a vacuum state, 1000 grams of liquid propylene monomer was added into the reactor, then 0.25 mol of triethylaluminum, 20 milligrams of olefin polymerization catalyst A6 and 0.2 grams of hydrogen were sequentially added at 30°C, and then the reaction temperature was raised to 70°C for 0.1 hours. 82 grams of polymer was obtained, and the polymerization activity was 24.2 kg / g Ti. The polymer particle bulk density was 0.25 g / mL.

[0106] In a vacuum state, 1000 grams of liquid propylene monomer was added into the reactor, then 0.25 mol of triethylaluminum, 20 milligrams of olefin polymerization catalyst A6 and 0.2 grams of hydrogen were sequentially added at 30°C, and then the reaction temperature was raised to 70°C for 1.0 hours. 505 grams of polymer was obtained, and the polymerization activity was 1201 kg / g Ti. The polymer particle bulk density was 0.32 g / mL.

[0107] In a vacuum state, 1000 grams of liquid propylene monomer was added into the reactor, then 0.25 mol of triethylaluminum, 20 milligrams of olefin polymerization catalyst A6 and 0.2 grams of hydrogen were sequentially added at 30°C, and then the reaction temperature was raised to 70°C for 2.0 hours. 756 grams of polymer was obtained, and the polymerization activity was 1800 kg / g Ti. The polymer particle bulk density was 0.34 g / mL.

[0108] Application Example 1

[0109] This application example is used to illustrate the application of the olefin polymerization catalyst provided by the present application in the synthesis of polypropylene thermoplastic elastomer.

[0110] In a vacuum state, 450 grams of liquid propylene monomer was added into the reactor, then 0.25 mol of triethylaluminum, 20 milligrams of olefin polymerization catalyst A1 and 0.1 grams of hydrogen were sequentially added at 30°C, and then the reaction temperature was raised to 75°C for 0.2 hours. Then the residual propylene monomer in the reactor was evacuated and the temperature was lowered to 50°C, then the mixed gas of ethylene and propylene was continuously punched into the reactor, the mass ratio of ethylene and propylene was 1:1.5, and when the final consumption of ethylene and propylene mixed gas was 260 grams, the reaction was stopped, and 500 grams of polymer was obtained. According to the mass calculation, the mass percentage of ethylene-propylene rubber in the polymer was 52%. The polymer particles had good flowability and no sticking phenomenon.

[0111] Application Example 2

[0112] This application example is used to illustrate the application of the olefin polymerization catalyst provided by the present application in the synthesis of polypropylene thermoplastic elastomer.

[0113] In a vacuum state, 450 grams of liquid propylene monomer was added into the reactor, then 0.25 mol of triethylaluminum, 20 mg of olefin polymerization catalyst A1 and 0.02 g of hydrogen were added in turn at 30℃, and then the reaction temperature was raised to 75℃ for 0.2 hours. Then the residual propylene monomer in the reactor was exhausted and the temperature was reduced to 50℃, then the mixed gas of ethylene and propylene with a mass ratio of 1:1.5 was continuously punched into the reactor, and when the final consumption of the mixed gas of ethylene and propylene was 350 grams, the reaction was stopped, and 600 grams of polymer was obtained. According to the mass calculation, the mass percentage of ethylene-propylene rubber in the polymer was 58%. The polymer particles had good flowability and no sticking phenomenon.

Claims

1. A method for increasing the rubber content of polypropylene thermoplastic elastomer, characterized in that, The method involves adding an olefin polymerization catalyst during the propylene polymerization reaction; The olefin polymerization catalyst contains silicon tetrachloride-modified silica, transition metal components, and non-transition metal components; the transition metal components are titanium tetrahalide and / or alkoxy titanium, and the non-transition metal components are magnesium-containing compounds. Based on the total weight of the olefin polymerization catalyst, the content of silicon tetrachloride-modified silica is 0.5-50% by weight, and the total content of metal elements in the transition metal component and the non-transition metal component is 2-80% by weight; the content of transition metal elements in the transition metal component is 0.5-10% by weight, and the content of non-transition metal elements in the non-transition metal component is 2-30% by weight. The preparation method of the olefin polymerization catalyst includes the following steps: (1) Silicon tetrachloride-modified silica is reacted with a non-transition metal component containing magnesium compound at 30-150℃ for 1-50 hours to obtain a magnesium complex; (2) First, the magnesium complex is mixed with a portion of titanium tetrahalide and / or a portion of titanium alkoxy and reacted at -20°C to 0°C for 0.5-2 hours. Then, the temperature is raised to 80-130°C and reacted for 1-4 hours. Next, the reaction product is separated into solid and liquid components. The obtained solid product is reacted with the remaining portion of titanium tetrahalide and / or the remaining portion of titanium alkoxy at 80-130°C for 1-4 hours to obtain an olefin polymerization catalyst. The preparation method of the silicon tetrachloride-modified silicon dioxide specifically includes the following steps: Silica is dispersed in a solvent to obtain a silica dispersion solution. At room temperature, silicon tetrachloride is added dropwise to the silica dispersion solution. After the addition is complete, the reaction continues for 2 to 24 hours. After the reaction is complete, the mixture is filtered and dried to obtain silicon tetrachloride-modified silica.

2. The method according to claim 1, characterized in that, The solvent is C5~C 10 The alkane; the concentration of the silicon dioxide in the solvent is 0.05~100g / L; the mass ratio of silicon tetrachloride to silicon dioxide is 0.1~100:

1.

3. The method according to claim 1, characterized in that, Based on the total weight of the olefin polymerization catalyst, the content of silicon tetrachloride-modified silica is 5-20% by weight, and the total content of metal elements in the transition metal component and the non-transition metal component is 10-20% by weight.

4. The method according to claim 1, characterized in that, The titanium tetrahalide is at least one selected from TiCl4, TiBr4, and TiI4; the general formula of the alkoxy titanium is R. 4 p Ti(OR 5 ) 4-p R 4 and R 5 Each is independently a C1-C4 alkyl group, p is an integer from 0 to 3; the magnesium-containing compound has the general formula MgX. 1 2 magnesium halides and / or those with the general formula RMgX 2 Grignard reagents; in MgX 1 In 2, X 1 For F, Cl, Br, or I; in RMgX 2 In this context, R represents C1-C 10 Alkyl group, X 2 It can be F, Cl, Br or I.

5. The method according to claim 1, characterized in that, The alkoxy titanium is at least one of tetrabutyl titanate, methyltriethoxy titanium, methyltrimethoxy titanium, and tetraethyl titanate.

6. The method according to claim 1, characterized in that, The olefin polymerization catalyst further comprises an internal electron donor compound and a co-catalyst; the internal electron donor compound is a diether compound and / or a carboxylic acid ester compound; the co-catalyst is an alkylaluminum compound with the general formula Al(OR′). q R′′ 3-q R′ and R′′ are each independently C2-C 10 Alkyl groups, 0 ≤ q ≤ 3.

7. The method according to claim 1, characterized in that, In step (1), the weight ratio of the silicon tetrachloride-modified silicon dioxide to the non-transition metal component containing magnesium compound is 1:0.5-99; in step (2), the mass ratio of the magnesium complex to titanium tetrahalide and / or titanium alkoxy is 1:1-100.

8. The method according to claim 1, characterized in that, In step (1), the weight ratio of the silicon tetrachloride-modified silicon dioxide to the non-transition metal component containing magnesium compound is 1:0.5-50.

9. The method according to claim 1, characterized in that, The portion of alkoxy titanium and the remaining portion of 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 portion of titanium tetrahalide to the remaining portion of titanium tetrahalide is 1:0.1~10.

10. The method according to claim 1, characterized in that, The preparation method also includes the addition of an internal electron donor compound. The internal electron donor compound is added as follows: after reacting the magnesium complex with a portion of the transition metal component at -20 to 0 for 0.5 to 2 hours, the internal electron donor compound is added to the reaction system.