Ultra-clean polypropylene resin and method for producing the same

Abstract

An ultra-clean polypropylene resin and its preparation method, comprising propylene prepolymerization, liquid phase bulk polymerization, gas phase polymerization, polypropylene drying, purification and extrusion granulation, in which a highly active polypropylene catalyst is first subjected to a stepwise prepolymerization treatment, the prepolymer slurry is then injected into two tank reactors connected in series for liquid phase bulk polymerization, and then injected into a fluidized bed reactor for gas phase polymerization, the polypropylene base is washed with a blended solvent made of hydrocarbon and alcohol solvents to remove catalyst residues and amorphous polypropylene, and a low ash, long-lasting antioxidant complex auxiliary is used to avoid secondary pollution of polypropylene products caused by impurities, thereby realizing the industrialized production of ultra-clean polypropylene.

Description

[Technical Field]

[0001] The present invention relates to the field of polymer resins, and more specifically to ultra-clean polypropylene resins and methods for producing the same, and in particular to ultra-clean polypropylene resins and methods for producing the same. [Background technology]

[0002] Polypropylene, abbreviated as PP, is a colorless, odorless, non-toxic, and translucent solid material. It is a thermoplastic synthetic resin with excellent performance, a colorless, translucent, lightweight, general-purpose plastic. Due to its chemical resistance, heat resistance, electrical insulation, high-strength mechanical properties, and good abrasion resistance, polypropylene has been rapidly developed and applied in many fields since its introduction, including machinery, automobiles, electronics, construction, textiles, packaging, agriculture, forestry, fisheries, and the food industry. In recent years, the rapid development of industries such as packaging, electronics, and automobiles has greatly accelerated the development of the industry.

[0003] Polypropylene is used to manufacture insulating housings for home appliances and liners for washing machines, and is commonly used as an insulating material for electrical wires, cables, and other electrical equipment. When manufacturing barrier films, it can be produced using conventional film-forming processes, which are simple and have low manufacturing costs.

[0004] Chinese Patent No. 201310519301.0 discloses a method for producing a material specifically for lithium-ion battery homopolypropylene barrier film. In this invention, a highly active, hydrogen-sensitive propylene polymerization catalyst is used, the propylene polymerization activator is triethylaluminum, the amount of which is added is controlled to 7.0 L / h or less, and the external electron donor is a mixture of dicyclopentyl dimethoxysilane and tetraethoxysilane in a 1:1 to 1:8 molar ratio. The isotacticity of the product exceeds 98%, the melt flow rate is 2.6 to 3.0 g / 10 min, and the ash content is 50 to 100 ppm. The ash content index does not meet the requirements of high-end electrical applications.

[0005] Chinese Patent 201080045745.X discloses catalyst components for olefin polymerization using diol ester type and diether type internal electron donors, a method for producing the catalyst components, a catalyst containing the catalyst components, and a method for olefin polymerization using the catalyst, which are used in the production of low-ash polypropylene products. Although the ash content of products produced by this technology is low at 30 ppm, it still cannot meet the requirements of high-grade dry-type power electronic capacitors. [Overview of the Initiative]

[0006] In response to the problem of high ash content in products resulting from direct polymerization using only highly active catalysts, as described in the conventional technology, the present invention aims to provide a method for producing ultra-clean polypropylene resin.

[0007] Another object of the present invention is to provide an ultra-clean polypropylene resin.

[0008] Another object of the present invention is to provide a method for producing polypropylene resin.

[0009] A further object of the present invention is to provide a polypropylene resin.

[0010] To achieve the above objective, the present invention provides, in one embodiment, a method for producing an ultra-clean polypropylene resin comprising propylene prepolymerization, liquid-phase bulk polymerization, gas-phase polymerization, polypropylene drying, purification, and extrusion granulation.

[0011] Propylene prepolymerization: After preparing a catalyst slurry containing a main catalyst, a co-catalyst, and a solvent in a prepolymerization reactor, propylene is introduced to carry out a prepolymerization reaction to obtain a prepolymer slurry.

[0012] Liquid phase bulk polymerization: Using propylene as a raw material, a polymerization reaction is carried out in the presence of the prepolymer slurry, a cocatalyst, an external electron donor, and hydrogen gas to obtain a crude polypropylene product slurry, and the external electron donor is 9,9-di(methoxymethyl)fluorene.

[0013] Gas-phase polymerization: The crude polypropylene product slurry obtained by liquid-phase bulk polymerization is put into a gas-phase fluidized bed reactor to carry out a polymerization reaction.

[0014] Polypropylene drying: The outlet material of the gas-phase fluidized bed reactor first undergoes gas-solid separation, and the solid-phase component is put into a dryer for drying to obtain polypropylene powder.

[0015] Purification: The dried polypropylene powder is prepared into a slurry with a composite solvent, stirred and purified, and then the slurry is subjected to solid-liquid separation to obtain wet polypropylene powder, which is dried to obtain ultra-clean polypropylene powder.

[0016] Extrusion granulation: After mixing the purified ultra-clean polypropylene powder and an antioxidant composite auxiliary agent, extrusion granulation is carried out to obtain the ultra-clean polypropylene resin.

[0017] Hereinafter, each process of propylene prepolymerization, liquid-phase bulk polymerization, gas-phase polymerization, polypropylene drying, purification, and extrusion granulation will be described in detail.

[0018] I. Propylene prepolymerization: After preparing a catalyst slurry containing a main catalyst, a cocatalyst, and a solvent in a prepolymerization reactor, propylene is introduced to carry out a prepolymerization reaction to obtain a prepolymer slurry.

[0019] In the prepolymerization process, a thin layer of polypropylene is formed on the surface of the catalyst particles.

[0020] Preferably, in the prepolymerization process, the mass ratio of propylene to the main catalyst is 2.5 - 10 kg / kg, and the mass ratio of the cocatalyst to the main catalyst is 0.027 - 0.075 kg / kg.

[0021] According to some specific embodiments of the present invention, preferably, the prepolymerization reaction comprises a first stage in which the prepolymerization temperature is -5°C to 15°C, the propylene supply rate is 10 to 45 kg / h, and the prepolymerization time is 0.5 to 3 h, and a second stage in which the prepolymerization temperature is 5°C to 35°C, the propylene supply rate is 15 to 55 kg / h, and until all of the propylene for prepolymerization is added to the prepolymerization reactor.

[0022] According to some specific embodiments of the present invention, the solvent in the catalyst slurry is preferably selected from C4-C10 alkanes. More preferably, the C4-C10 alkanes are one or more combinations selected from butane, pentane, hexane, heptane, octane, nonane, and decane, and most preferably hexane. The main catalyst according to the present invention is described in Chinese Patent No. 201080045745.X and may be incorporated into the present invention, or it may be commercially available. That is, the main catalyst of the present invention only needs to satisfy the activity requirement, and the activity of the main catalyst is at least 100,000 times, and the specific method for calculating the catalytic activity is the mass ratio of the polymer obtained by propylene polymerization by the catalyst to the catalyst per unit time.

[0023] According to some specific embodiments of the present invention, preferably, the main catalyst is a Zn-based catalyst comprising a MgCl2 support, a TiCl4 active center, and an internal electron donor, wherein the internal electron donor is one or more selected from alkyl-substituted 1,3-diethers, aryl-substituted 1,3-diethers, succinic acid esters, malonic acid esters, and diol esters.

[0024] According to some specific embodiments of the present invention, preferably, the aryl group of the aryl-substituted 1,3-diether is monocyclic or polycyclic C 4-16 The aryl group is selected from aryl groups. More specifically, the aryl group of the aryl-substituted 1,3-diethers is one selected from cyclopentadienyl, indenyl, fluorenyl, and their derivatives.

[0025] According to some specific embodiments of the present invention, preferably, the structure of the alkyl-substituted 1,3-diether is represented by the following formula (I), and the structure of the aryl-substituted 1,3-diether is represented by the following formula (II) or formula (III). [ka]

[0026] However, R1, R2, R3, R4, R5, and R6 are either the same or different, and each is independent of C 1-10 It is a linear or branched alkyl group.

[0027] According to some specific embodiments of the present invention, preferably R1, R2, R3, R4, R5, and R6 are the same or different, and each is independently a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a heptyl group, an octyl group, a nonyl group, or a decyl group.

[0028] According to some specific embodiments of the present invention, the structures of the succinic acid esters and malonic acid esters are preferably represented by the following formulas (IV) and (V), respectively. [ka]

[0029] However, R7, R8, R9 and R 10 They are identical or different, and each is independently C 1-10 A linear or branched alkyl group, more preferably R7, R8, R9 and R 10 These are, independently, a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a heptyl group, an octyl group, a nonyl group, or a decyl group.

[0030] According to some specific embodiments of the present invention, the co-catalyst is preferably an alkylaluminum compound, more preferably one or more combinations selected from trialkylaluminum, alkylaluminoxane, a combination of trialkylaluminum and alkylaluminum halide, or a combination of trialkylaluminum and alkylaluminum hydride, and most preferably triethylaluminum.

[0031] II. Liquid-phase bulk polymerization: Using propylene as a raw material, a polymerization reaction is carried out in the presence of the prepolymer slurry, a co-catalyst, an external electron donor, and hydrogen gas to obtain a crude polypropylene product, wherein the external electron donor is 9,9-di(methoxymethyl)fluorene.

[0032] According to some specific embodiments of the present invention, the liquid-phase bulk polymerization preferably includes the following steps:

[0033] Propylene, prepolymer slurry, co-catalyst, external electron donor, and hydrogen gas are added to the first reaction vessel, and the polymerization reaction is carried out at a temperature of 60°C to 75°C and a pressure of 2.5 to 3.5 MPa. The flow rate of the reaction slurry (obtained polypropylene powder molten material) at the outlet of the first reaction vessel is 4.0 to 4.5 g / 10 min, and the hydrogen gas concentration in the first reaction vessel is 1000 to 3000 ppm. Subsequently, the reaction slurry is added to the second reaction vessel, hydrogen gas is introduced, and the polymerization reaction is carried out at a temperature of 60°C to 75°C and a pressure of 2.5 to 3.5 MPa. The flow rate of the reaction slurry (obtained polypropylene powder molten material) at the outlet of the second reaction vessel is 3.5 to 4.5 g / 10 min, and the hydrogen gas concentration in the second reaction vessel is 1000 to 2000 ppm.

[0034] According to some specific embodiments of the present invention, preferably, in the liquid-phase bulk polymerization process, the mass ratio of the main catalyst to propylene is 0.03 to 0.05 kg / t, the mass ratio of the co-catalyst to propylene is 0.015 to 0.0225 kg / t, and the mass ratio of the external electron donor to the co-catalyst is 0 to 0.015 kg / kg, not including 0.

[0035] According to some specific embodiments of the present invention, preferably, both the first and second reaction vessels are tank-type polymerization reactors and are connected in series (resulting in a fully mixed-flow multi-stage reactor series polymerization process).

[0036] 3. Gas-phase polymerization: The crude polypropylene slurry obtained by liquid-phase bulk polymerization is placed in a gas-phase fluidized bed reactor and subjected to polymerization.

[0037] According to some specific embodiments of the present invention, preferably, the polymerization temperature in gas-phase polymerization is 75-85°C, the polymerization pressure is 1.5-2.0 MPa, the melt flow rate of polypropylene powder at the outlet of the gas-phase fluidized bed reactor is 2.8-3.2 g / 10 min, the ash content is less than 30 ppm, and the isotacticity is greater than 98.5%.

[0038] IV. Polypropylene Drying: The outlet material of the gas-phase fluidized bed reactor is first subjected to gas-solid separation. The solid phase component (polypropylene powder) (the separated gas phase portion enters the recovery system and is recovered and utilized) is placed in a dryer and dried to obtain polypropylene powder.

[0039] According to some specific embodiments of the present invention, preferably, the solid phase component is placed in a drying oven and dried by a convection-driven inert gas. The inert gas is preferably nitrogen gas, and the drying temperature is preferably 100 to 110°C.

[0040] According to some specific embodiments of the present invention, the drying temperature is preferably 95 to 115°C, and more preferably 100 to 110°C.

[0041] 5. Purification: The dried polypropylene powder is prepared into a slurry with a composite solvent, purified by stirring, and then the slurry is subjected to solid-liquid separation to obtain wet polypropylene powder. After drying, ultra-clean polypropylene powder is obtained.

[0042] According to some specific embodiments of the present invention, preferably the purification temperature is 30 to 150°C and the time is 0.1 to 5 hours, and more preferably the purification temperature is 50 to 120°C and the time is 0.5 to 3 hours.

[0043] According to some specific embodiments of the present invention, preferably, the proportion of solvent in the wet polypropylene powder is 15 to 35% (with the total mass of the polypropylene powder being 100%), and more preferably 15 to 30%.

[0044] According to some specific embodiments of the present invention, preferably, in the purification process, the mass concentration of polypropylene powder in the prepared slurry is 10 to 40%.

[0045] According to some specific embodiments of the present invention, preferably, the ash content of the ultra-clean polypropylene powder is less than 10 ppm.

[0046] According to some specific embodiments of the present invention, the solid-liquid separation may preferably be performed by centrifugal separation.

[0047] According to some specific embodiments of the present invention, the composite solvent preferably comprises a hydrocarbon substance and an alkyl alcohol, wherein the hydrocarbon substance is preferably C5-C 20 The hydrocarbon is a normal alkane or isoalkane, such as pentane, hexane, heptane, octane, nonane, or decane, and the alkyl alcohol is preferably methanol, ethanol, propanol, or butanol. The mass ratio of the hydrocarbon to the alkyl alcohol is preferably (2-6):1.

[0048] More preferably, the composite solvent is a composite solvent of hexane and ethanol, with a mass ratio of 4:1.

[0049] 6. Extrusion granulation: After mixing the purified ultra-clean polypropylene powder with an antioxidant composite additive, the mixture is extruded and granulated to obtain the ultra-clean polypropylene resin.

[0050] The ash content of the ultra-clean polypropylene resin obtained by the extrusion granulation method of the present invention is less than 20 ppm.

[0051] According to some specific embodiments of the present invention, preferably, the antioxidant complex additive comprises an acid scavenger, a primary antioxidant, and an auxiliary antioxidant.

[0052] Preferably, the acid scavenger is a combination of one or more selected from metal stearates and hydrotalcite, preferably zinc stearate and calcium stearate, and the mass ratio of the ultra-clean polypropylene powder to the acid scavenger is (10000~100000):1.

[0053] Preferably, the main antioxidant is pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid], 1,3,5-tris(3,5-di-tert-butyl-4-hydroxybenzyl)-S-triazine-2,4,6-(1H,3H,5H)trione, β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid stearyl, 1,3,5-trimethyl-2,4,6-tris(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid The antioxidant is one or more selected from droxybenzyl)benzene and 1,1,3-tris(2-methyl-4-hydroxy-5-tert-butylphenyl)butane, with pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid] (i.e., antioxidant 1010) and 1,3,5-tris(3,5-di-tert-butyl-4-hydroxybenzyl)-S-triazine-2,4,6-(1H,3H,5H)trione being preferred.

[0054] Preferably, the mass ratio of the ultra-clean polypropylene powder to the main antioxidant is (1000-10000):1.

[0055] Preferably, the auxiliary antioxidant is one or more selected from dilauryl thiodipropionate, distearyl thiodipropionate, dimyristyl thiodipropionate, tris(nonylphenyl) phosphite, bis(octadecyl)pentaerythritol diphosphite, tris(2,4-t-butylphenyl) phosphite, and bis(2,4-di-tert-butylphenyl)pentaerythritol diphosphite, with dilauryl thiodipropionate and tris(2,4-t-butylphenyl) phosphite (i.e., antioxidant 168) being preferred.

[0056] Preferably, the mass ratio of the ultra-clean polypropylene powder to the auxiliary antioxidant is (100-10000):1.

[0057] On the other hand, the present invention provides an ultra-clean polypropylene resin manufactured by the above manufacturing method.

[0058] In the manufacturing method of the present invention, first, a highly active polypropylene catalyst is subjected to a stepwise prepolymerization treatment. Next, the prepolymer slurry is injected into two tank reactors connected in series for liquid-phase bulk polymerization, and then injected into one fluidized bed reactor for gas-phase polymerization. The polypropylene base is washed with a compound solvent produced from hydrocarbon and alcohol-based solvents to remove catalyst residue and amorphous polypropylene. Secondary contamination of the polypropylene product by impurities is avoided by using a low-ash, long-lasting antioxidant composite additive, thereby realizing the industrial production of ultra-clean polypropylene.

[0059] Furthermore, the present invention includes the step of polymerizing propylene as a raw material to obtain a crude polypropylene product, A method for producing a polypropylene resin, comprising the step of purifying the obtained crude polypropylene product to obtain the polypropylene resin, The present invention provides a method for producing polypropylene resin, which includes the purification process of adding crude polypropylene to a composite solvent, thoroughly contacting the crude polypropylene with the composite solvent at 30 to 120°C to form a polypropylene slurry, separating the polypropylene from the composite solvent to obtain polypropylene powder, and drying the polypropylene powder to obtain the polypropylene resin (ultra-pure polypropylene powder).

[0060] In the polypropylene powder obtained by separating polypropylene from a composite solvent, the solvent ratio is 15-35% (assuming the total mass of the polypropylene powder is 100%).

[0061] According to some specific embodiments of the present invention, the crude polypropylene product has a melt flow rate of 0.1 to 1000 g / 10 min and a molecular weight distribution of 3 to 15 (weight average / number average).

[0062] According to some specific embodiments of the present invention, the composite solvent is a mixed solvent selected from at least one alkyl alcohol having 1 to 10 carbon atoms and at least one alkane having 5 to 20 carbon atoms that is liquid at room temperature.

[0063] According to some specific embodiments of the present invention, the alkyl alcohol having 1 to 10 carbon atoms is one or more selected from methanol, ethanol, propanol, and butanol.

[0064] According to some specific embodiments of the present invention, the alkanes having 5 to 20 carbon atoms and being liquid at room temperature are one or more selected from pentane, hexane, heptane, octane, nonane, and decane.

[0065] According to some specific embodiments of the present invention, the mass ratio of an alkyl alcohol having 1 to 10 carbon atoms to an alkane having 5 to 20 carbon atoms that is liquid at room temperature is 1:(2 to 6).

[0066] According to some specific embodiments of the present invention, the mass ratio of an alkyl alcohol having 1 to 10 carbon atoms to an alkane having 5 to 20 carbon atoms that is liquid at room temperature is 1:4.

[0067] According to some specific embodiments of the present invention, the purification includes adding the crude polypropylene product to a composite solvent and bringing the crude polypropylene product and the composite solvent into sufficient contact at 50 to 100°C to form a polypropylene slurry.

[0068] According to some specific embodiments of the present invention, the sufficient contact includes contacting the crude polypropylene product with the composite solvent for 0.1 to 5 hours (the time the slurry remains in the reaction vessel) under stirring conditions.

[0069] According to some specific embodiments of the present invention, the sufficient contact includes contacting the crude polypropylene product with the composite solvent for 0.5 to 3 hours under stirring conditions.

[0070] According to some specific embodiments of the present invention, the sufficient contact includes contacting the crude polypropylene product with the composite solvent under stirring conditions at a stirring speed of 10 to 150 rpm.

[0071] According to some specific embodiments of the present invention, the mass concentration of polypropylene in the polypropylene slurry is 10 to 40%.

[0072] According to some specific embodiments of the present invention, the mass concentration of polypropylene in the polypropylene slurry is 15-30%.

[0073] According to some specific embodiments of the present invention, the purification includes separating polypropylene from a composite solvent by centrifugation to obtain polypropylene powder, and then drying the polypropylene powder at 95-120°C to obtain the polypropylene resin.

[0074] According to some specific embodiments of the present invention, the purification includes separating polypropylene from a composite solvent by centrifugation to obtain polypropylene powder, and then drying the polypropylene powder at 95 to 115°C to obtain the polypropylene resin.

[0075] According to some specific embodiments of the present invention, the drying time is 0.5-2 hours.

[0076] According to some specific embodiments of the present invention, the ash content of the polypropylene resin obtained by drying polypropylene powder is less than 10 ppm.

[0077] According to some specific embodiments of the present invention, the ash content of the polypropylene resin obtained by drying polypropylene powder is 5 to 10 ppm.

[0078] According to some specific embodiments of the present invention, the method further comprises the step of mixing the obtained polypropylene resin with an antioxidant composite additive and then extruding and granulating it.

[0079] According to some specific embodiments of the present invention, the antioxidant complex additive is a combination selected from an acid scavenger, a primary antioxidant, and an auxiliary antioxidant.

[0080] According to some specific embodiments of the present invention, with the total mass of the antioxidant complex additive being 100%, the mass percentage content of the acid scavenger, main antioxidant, and auxiliary antioxidant is 0.1-1%, 65-90%, and 9.4-34.4%, respectively.

[0081] According to some specific embodiments of the present invention, the acid scavenger is one or more combinations selected from metal stearates and hydrotalcite.

[0082] According to some specific embodiments of the present invention, the metal stearate is selected from zinc stearate and / or calcium stearate.

[0083] According to some specific embodiments of the present invention, the main antioxidant is one or a combination of several selected from pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid], 1,3,5-tris(3,5-di-tert-butyl-4-hydroxybenzyl)-S-triazine-2,4,6-(1H,3H,5H)trione, β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid stearyl, 1,3,5-trimethyl-2,4,6-tris(3,5-di-tert-butyl-4-hydroxybenzyl)benzene, and 1,1,3-tris(2-methyl-4-hydroxy-5-tert-butylphenyl)butane.

[0084] According to some specific embodiments of the present invention, the main antioxidant is one or more selected from pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid] and 1,3,5-tris(3,5-di-tert-butyl-4-hydroxybenzyl)-S-triazine-2,4,6-(1H,3H,5H)trione.

[0085] According to some specific embodiments of the present invention, the auxiliary antioxidant is one or a combination of several selected from dilauryl thiodipropionate, distearyl thiodipropionate, dimyristyl thiodipropionate, tris(nonylphenyl) phosphite, bis(octadecyl)pentaerythritol diphosphite, tris(2,4-t-butylphenyl) phosphite, and bis(2,4-di-tert-butylphenyl)pentaerythritol diphosphite.

[0086] According to some specific embodiments of the present invention, the auxiliary antioxidant is dilauryl thiodipropionate and / or tris(2,4-t-butylphenyl) phosphite.

[0087] According to some specific embodiments of the present invention, the mass percentage content of the antioxidant composite additive is 0.2% to 1%, with the mass of the obtained polypropylene resin being 100%.

[0088] According to some specific embodiments of the present invention, the step of polymerizing propylene as a raw material includes the following steps:

[0089] Propylene prepolymerization step: This step includes forming a thin polypropylene layer on the surface of catalyst particles by polymerizing a predetermined amount of propylene in the presence of a main catalyst and a co-catalyst, wherein the mass ratio of propylene to the main catalyst in the prepolymerization step is 2.5 to 10 kg / kg, and the mass ratio of the co-catalyst to the main catalyst in the prepolymerization step is 0.18 to 0.5 kg / kg, thereby obtaining a prepolymer slurry.

[0090] Polymerization step: This step includes carrying out a polymerization reaction using propylene as a raw material in the presence of the prepolymer slurry, a co-catalyst, an external electron donor, and hydrogen gas to obtain a crude polypropylene product.

[0091] According to some specific embodiments of the present invention, the propylene prepolymerization step includes introducing propylene at a rate of 10 to 45 kg / h in the presence of a main catalyst and a co-catalyst, polymerizing at -5°C to 15°C for 0.5 to 3 hours, and then introducing propylene at a rate of 15 to 55 kg / h at a rate of 5°C to 35°C until all of the remaining propylene is added to the prepolymerization reactor.

[0092] According to some specific embodiments of the present invention, the propylene prepolymerization step includes introducing propylene at a rate of 10 to 45 kg / h in the presence of a main catalyst and a co-catalyst, polymerizing at -5°C to 15°C for 0.5 to 3 hours, and then introducing propylene at a rate of 15 to 55 kg / h and polymerizing at 5°C to 35°C for 1 to 4 hours.

[0093] According to some specific embodiments of the present invention, the propylene prepolymerization step includes adding a main catalyst to a linear or branched alkane having 4 to 10 carbon atoms, wherein the mass concentration of the main catalyst in the alkane solution is 0.1 to 3%, and further adding propylene and a co-catalyst to carry out the polymerization reaction.

[0094] According to some specific embodiments of the present invention, the reaction heat of the prepolymerization step is removed by freezing water.

[0095] According to some specific embodiments of the present invention, after obtaining a prepolymer slurry in a prepolymerization step, the prepolymer slurry is further diluted by adding a predetermined amount of an alkane having 4 to 10 carbon atoms, and the mass concentration of the polymer in the diluted prepolymer slurry is 0.01 to 5.5%.

[0096] According to some specific embodiments of the present invention, the C4-C10 alkane is one or more selected from butane, pentane, hexane, heptane, octane, nonane, and decane.

[0097] According to some specific embodiments of the present invention, the mass ratio of the main catalyst to the propylene added in the polymerization step is 0.03 to 0.05 kg / t, the mass ratio of the co-catalyst added in the polymerization step to the propylene added in the polymerization step is 0.1 to 0.15 kg / t, and the mass ratio of the external electron donor to the co-catalyst added in the polymerization step is 0 to 0.1 kg / kg.

[0098] Here, it can be understood that if the mass ratio of the external electron donor to the co-catalyst is 0, it is not necessary to add the external electron donor.

[0099] According to some specific embodiments of the present invention, the mass ratio of the co-catalyst to the main catalyst added in the polymerization step is 3.2 to 3.6 kg / kg.

[0100] According to some specific embodiments of the present invention, the polymerization step includes the following steps:

[0101] Liquid-phase bulk polymerization step: This step includes carrying out liquid-phase bulk polymerization using propylene as a raw material in the presence of the prepolymer slurry, co-catalyst, external electron donor, and hydrogen gas at a temperature of 65°C to 75°C and a pressure of 2.5 to 3.5 MPa.

[0102] The gas-phase polymerization step includes performing gas-phase polymerization on the slurry obtained by liquid-phase bulk polymerization at a temperature of 75°C to 85°C and a pressure of 1.5 to 2.0 MPa to obtain a crude polypropylene product.

[0103] According to some specific embodiments of the present invention, the propylene raw material in the liquid-phase bulk polymerization step is purified propylene.

[0104] According to some specific embodiments of the present invention, the water content of the purified propylene is 5 to 10 mg / kg, and the carbon monoxide content is 0.1 to 0.5 mL / m³. 3 The carbon dioxide content is 0.1-0.5 mL / m³. 3 That is the case.

[0105] According to some specific embodiments of the present invention, the liquid-phase bulk polymerization step includes adding propylene, a prepolymer slurry, a co-catalyst, an external electron donor, and hydrogen gas to a first reaction vessel, carrying out a polymerization reaction at a temperature of 60°C to 75°C and a pressure of 2.5 to 3.5 MPa, wherein the flow rate of the reaction slurry (obtained polypropylene powder molten material) at the outlet of the first reaction vessel is 4.0 to 4.5 g / 10 min, and the hydrogen gas concentration in the first reaction vessel is 1000 to 3000 ppm. Subsequently, the reaction slurry is added to a second reaction vessel, hydrogen gas is introduced, and a polymerization reaction is carried out at a temperature of 60°C to 75°C and a pressure of 2.5 to 3.5 MPa, wherein the flow rate of the reaction slurry (obtained polypropylene powder molten material) at the outlet of the second reaction vessel is 3.5 to 4.5 g / 10 min, and the hydrogen gas concentration in the second reaction vessel is 1000 to 2000 ppm.

[0106] According to some specific embodiments of the present invention, in the liquid-phase bulk polymerization step, propylene, prepolymer slurry, cocatalyst, external electron donor, and hydrogen gas are added to a first reaction vessel, and a polymerization reaction is carried out at a temperature of 70 °C and a pressure of 3.0 MPa. The flow rate of the reaction slurry (the obtained polypropylene powder melt) at the outlet of the first reaction vessel is 4.5 g / 10 min, and the hydrogen gas concentration in the first reaction vessel is 2890 ppm. Then, the reaction slurry is added to a second reaction vessel, hydrogen gas is introduced, and a polymerization reaction is carried out at a temperature of 64 °C and a pressure of 2.6 MPa. The flow rate of the reaction slurry (the obtained polypropylene powder melt) at the outlet of the second reaction vessel is 4.5 g / 10 min, and the hydrogen gas concentration in the second reaction vessel is 1300 ppm.

[0107] According to some specific embodiments of the present invention, in the liquid-phase bulk polymerization step, propylene, prepolymer slurry, cocatalyst, external electron donor, and hydrogen gas are added to a first reaction vessel, and a polymerization reaction is carried out at a temperature of 70 °C and a pressure of 3.0 MPa (liquid level 49%). The flow rate of the reaction slurry (the obtained polypropylene powder melt) at the outlet of the first reaction vessel is 4.5 g / 10 min. The supply rate of the prepolymer slurry is 14.0 kg / h, the supply rate of propylene is 5.7 t / h, the supply rate of triethylaluminum is 0.8 kg / h, the supply rate of cyclohexylmethyldimethoxysilane is 0.07 kg / h, and the supply rate of hydrogen gas is 4.9 Nm 2 / h. The hydrogen gas concentration in the first reaction vessel is 2890 ppm. Then, the reaction slurry is added to a second reaction vessel, hydrogen gas is introduced, and the supply rate of hydrogen gas is 2.0 Nm 2 / h. A polymerization reaction is carried out at a temperature of 64 °C and a pressure of 2.6 MPa (liquid level 44%). The flow rate of the reaction slurry (the obtained polypropylene powder melt) at the outlet of the second reaction vessel is 4.5 g / 10 min, and the hydrogen gas concentration in the second reaction vessel is 1300 ppm.

[0108] According to some specific embodiments of the present invention, the first reaction vessel and the second reaction vessel are connected in series (resulting in a completely mixed flow multi-stage reactor series polymerization process).

[0109] According to some specific embodiments of the present invention, the gas-phase polymerization is carried out in a gas-phase fluidized bed reactor.

[0110] According to some specific embodiments of the present invention, a polypropylene powder melt is obtained by gas-phase polymerization, and the flow rate of the polypropylene powder melt at the reactor outlet during gas-phase polymerization is 2.8 to 3.2 g / 10 min.

[0111] According to some specific embodiments of the present invention, the gas-phase polymerization step includes vapor polymerization of the slurry obtained by liquid-phase bulk polymerization at a temperature of 80°C and a pressure of 1.8 MPa to obtain a crude polypropylene product.

[0112] According to some specific embodiments of the present invention, the ash content of the crude polypropylene product obtained by gas-phase polymerization is less than 30 ppm.

[0113] According to some specific embodiments of the present invention, the ash content of the crude polypropylene product obtained by gas-phase polymerization is 30 ppm or less.

[0114] According to some specific embodiments of the present invention, the ash content of the crude polypropylene product obtained by gas-phase polymerization is 10 to 30 ppm.

[0115] According to some specific embodiments of the present invention, the step of polymerizing propylene as a raw material further includes the step of drying the solid obtained after the polymerization reaction at 95°C to 115°C, thereby obtaining a crude polypropylene product.

[0116] According to some specific embodiments of the present invention, the solid obtained after the polymerization reaction is dried at 105°C.

[0117] According to some specific embodiments of the present invention, the drying in the step of polymerizing propylene as a raw material is carried out by convection of an inert gas in a drying oven.

[0118] According to some specific embodiments of the present invention, the inert gas is nitrogen gas. According to some specific embodiments of the present invention, the drying temperature in the step of polymerizing propylene as a raw material is 100 to 110°C.

[0119] According to some specific embodiments of the present invention, the step of polymerizing propylene as a raw material further includes the step of obtaining a solid by gas-to-solid separation of the reaction slurry obtained after the polymerization reaction.

[0120] According to some specific embodiments of the present invention, the step of polymerizing propylene as a raw material is performed by gas-solid separation using a cyclone separator.

[0121] According to some specific embodiments of the present invention, the main catalyst has high catalytic activity.

[0122] According to some specific embodiments of the present invention, the catalytic activity of the main catalyst is 80,000 to 120,000 times.

[0123] The catalytic activity is the mass ratio of polypropylene produced per unit time to the consumed catalyst.

[0124] According to some specific embodiments of the present invention, the main catalyst is a Zn-based catalyst, the co-catalyst is an alkylaluminum compound, and the external electron donor is one or more selected from cyclohexyldimethoxymethylsilane, p-dicyclopentyldimethoxysilane, diisopropyldimethoxysilane, and diisobutyldimethoxysilane.

[0125] According to some specific embodiments of the present invention, the Zn-based catalyst is a combination of one or more catalysts that use MgCl2 as a support, TiCl4 as an active center, and one selected from alkyl-substituted 1,3-diethers, aryl-substituted 1,3-diethers, succinic acid esters, and malonic acid esters as an internal electron donor.

[0126] According to some specific embodiments of the present invention, the aryl group of the aryl-substituted 1,3-diether is monocyclic or polycyclic C 4~16 Selected from aryl groups.

[0127] According to some specific embodiments of the present invention, the aryl group of the aryl-substituted 1,3-diether is selected from cyclopentadienyl, indenyl, fluorenyl and its derivatives.

[0128] According to some specific embodiments of the present invention, the structure of alkyl-substituted 1,3-diethers is represented by the following formula (I), and the structure of aryl-substituted 1,3-diethers is represented by the following formula (II) or formula (III). [ka]

[0129] However, R1, R2, R3, R4, R5, and R6 are either the same or different, and each is independent of C 1-10 It is a linear or branched alkyl group.

[0130] According to some specific embodiments of the present invention, R1, R2, R3, R4, R5, and R6 are the same or different and are independently a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a heptyl group, an octyl group, a nonyl group, or a decyl group.

[0131] According to some specific embodiments of the present invention, the structures of the succinic acid esters and malonic acid esters are represented by the following formulas (IV) and (V), respectively. [ka]

[0132] However, R7, R8, R9 and R 10 They are identical or different, and each is independently C 1-10 It is a linear or branched alkyl group.

[0133] According to some specific embodiments of the present invention, R7, R8, R9 and R 10 These are the same or different groups, and each is independently a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a heptyl group, an octyl group, a nonyl group, or a decyl group.

[0134] According to some specific embodiments of the present invention, the Zn-based catalyst is the Beijing Aoda HA-R catalyst.

[0135] According to some specific embodiments of the present invention, the alkylaluminum compound is one or more combinations selected from trialkylaluminum, alkylaluminoxane, a combination of trialkylaluminum and alkylaluminum halide, or a combination of trialkylaluminum and alkylaluminum hydride.

[0136] According to some specific embodiments of the present invention, the alkyl group of the alkylaluminum compound is C 1-10 It is a linear or branched alkyl group.

[0137] According to some specific embodiments of the present invention, the alkyl group of the alkylaluminum compound is a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a heptyl group, an octyl group, a nonyl group, or a decyl group.

[0138] The propyl group, butyl group, pentyl group, heptyl group, octyl group, nonyl group, and decyl group of the present invention may be in the form of a linear structure of the above groups, or they may be various branched isomers.

[0139] According to some specific embodiments of the present invention, the alkylaluminum compound is triethylaluminum.

[0140] According to some specific embodiments of the present invention, the method for producing the polypropylene resin includes the following steps.

[0141] (1) Propylene prepolymerization: The main catalyst is first diluted by mixing it with an alkane having 4 to 10 carbon atoms, and the mass concentration of the diluted slurry is 0.1 to 3%. Then, the co-catalyst and propylene are introduced into the prepolymerization reactor, and the materials are uniformly stirred by stirring in the reactor to carry out a two-stage prepolymerization reaction. In the first stage, the prepolymerization temperature is -5°C to 15°C, the amount of propylene added is 10 to 45 kg / h, and the prepolymerization time is 0.5 to 3 hours. In the second stage, the prepolymerization temperature is 5°C to 35°C, the amount of propylene added is 15 to 55 kg / h, and prepolymerization is carried out until all the remaining propylene is added to the prepolymerization reactor (prepolymerization tank).

[0142] (2) Liquid-phase bulk polymerization: Propylene, prepolymer slurry, co-catalyst, external electron donor and an appropriate amount of hydrogen gas are added to the first reactor (tank-type polymerization reactor) to carry out liquid-phase bulk polymerization. The polymerization temperature is 60-75°C, the polymerization pressure is 2.5-3.5 MPa, the melt flow rate of polypropylene powder at the outlet of the first reactor is 4.0-4.5 g / 10 min, the mass ratio of the main catalyst to propylene is 0.03-0.05 kg / t, and the mass ratio of the co-catalyst to propylene is 0.1-0.15 kg / t. The mass ratio of the donor to the co-catalyst is 0-0.1 kg / kg. Hydrogen gas is added to the first reactor, and the hydrogen gas concentration is 1000-3000 ppm. The slurry from the first reactor is placed in the second reactor (tank-type polymerization reactor) to carry out the polymerization reaction. The polymerization temperature is 60-75°C, the polymerization pressure is 2.5-3.5 MPa, the melt flow rate of the polypropylene powder at the outlet of the second reactor is 3.5-4.0 g / 10 min, and hydrogen gas is added to the second tank-type polymerization reactor, with a hydrogen gas concentration of 1000-2000 ppm.

[0143] (3) Gas-phase polymerization: The slurry from the second reactor is placed in a gas-phase fluidized bed reactor to carry out the polymerization reaction. The polymerization temperature is 75-85°C, the polymerization pressure is 1.5-2.0 MPa, and the melt flow rate of the polypropylene powder at the outlet of the gas-phase fluidized bed reactor is 2.8-3.2 g / 10 min.

[0144] (4) Polypropylene drying: The material at the outlet of the gas-phase fluidized bed reactor first enters a cyclone separator for gas-solid separation of the material. The solid phase component (polypropylene powder) (the separated gas phase portion enters a recovery system for recovery and utilization) enters a dryer and is dried by convection inert gas at a drying temperature of approximately 95-115°C.

[0145] (5) Polypropylene purification: The dried solid phase components are transported to a purification tank (by transport air), a predetermined amount of composite solvent is added to form a polymer powder slurry with a slurry concentration of 10-40%, and the polymer powder and composite solvent are allowed to come into sufficient contact at 30-120°C for 0.1-5 hours.

[0146] (6) Extrusion granulation: The antioxidant compound additive and the purified polypropylene powder were simultaneously added to a twin-screw extruder and extruded to obtain polypropylene resin.

[0147] In summary, the propylene polymerization of the present invention involves liquid-phase bulk polymerization using two tank reactors connected in series, followed by gas-phase polymerization using one fluidized bed reactor. Subsequently, the polypropylene base is washed with a compound solvent prepared from hydrocarbon and alcohol-based solvents to remove catalyst residues and amorphous polypropylene. Secondary contamination of the polypropylene product by impurities is avoided using an antioxidant composite additive, thereby realizing the industrial production of ultra-clean polypropylene.

[0148] Furthermore, the present invention provides a polypropylene resin manufactured by any of the manufacturing methods described above.

[0149] According to some specific embodiments of the present invention, the ash content of the polypropylene resin obtained by extrusion granulation is 30 ppm or less.

[0150] According to some specific embodiments of the present invention, the ash content of the polypropylene resin is 10 to 30 ppm.

[0151] According to some specific embodiments of the present invention, the ash content of the polypropylene resin is 15 to 30 ppm.

[0152] According to some specific embodiments of the present invention, the melt flow rate of the polypropylene resin obtained by extrusion granulation is 3.0 to 3.1 g / 10 min.

[0153] The present invention provides a polypropylene resin and a method for producing the same. The method of the present invention has the following advantages.

[0154] (1) In the present invention, catalytic activity can be improved by effectively activating the catalytic active sites inside the highly active catalyst particles through two-stage prepolymerization. Compared to the conventional technology, the polypropylene produced by the present invention has a lower ash content, and the product has good electrical properties that can meet the requirements of high-grade capacitors.

[0155] (2) In the present invention, a polypropylene segment coating layer can be formed around the titanium active center by two-step prepolymerization, thereby improving the mechanical strength of the catalyst particles. The polypropylene produced in the present invention has a low fine powder content, which is advantageous for the stable operation of industrial equipment.

[0156] (3) The bulk polymerization and advanced purification processes used in the present invention utilize organic complex solvents to remove metal impurities and polypropylene oligomers, and the resulting resin products have lower ash content and higher isotacticity, meeting the requirements of high-grade condensers. [Modes for carrying out the invention]

[0157] The technical aspects of the present invention will be described in detail below with reference to examples, but the scope of the claims of the present invention is not limited thereto.

[0158] Originating from raw materials or equipment: Propylene was supplied by Lanzhou Petrochemical Industry Co., Ltd., the catalyst by Beijing Aoda Catalyst Plant, triethylaluminum by Yingkou Xiangyang Catalyst Plant, cyclohexylmethyldimethoxysilane by Shandong Lujing Chemical Industry Technology Co., Ltd., and hydrogen gas by Lanzhou Petrochemical Industry Co., Ltd.

[0159] Evaluation and analysis methods: 1. Polymer melt index: Measured according to GB / T 3682-2000. 2. Polymer isotacticity: Measured according to GB / T 2412-2008. 3. Ash content of polymer: Measured according to GB / T 9345.1-2008.

[0160] Specific examples:

[0161] Example 1-1 Manufacturing of propylene prepolymer slurry 500 kg of hexane and 7 kg of triethylaluminum are added to the catalyst preparation tank, with a mass concentration of 15% triethylaluminum solution. 25 kg of titanium metal catalyst (Beijing Aoda HA-R catalyst) supported by magnesium chloride is added, and the mixture is stirred to form a homogeneous suspension. The temperature of the preparation tank is lowered to below 5°C with frozen brine, and 1500 kg of fresh hexane is added to adjust the concentration of the catalyst slurry. The mixture is then stirred and started until it reaches 80 r / min. In the first stage of prepolymerization, the automatic gas-phase propylene supply valve is opened, the propylene supply rate is adjusted to 10 kg / h, and the mixture is stirred and started until it reaches 40 r / min. The temperature of the preparation tank is lowered to below -5°C, and prepolymerization is carried out for 1 hour. In the second stage of prepolymerization, the propylene supply rate is adjusted to 15 kg / h, stirred and started until it reaches 40 r / min, the temperature of the preparation tank is lowered to 5°C, and prepolymerization is carried out until all 100 kg of propylene is consumed to obtain a propylene prepolymer slurry. The prepolymer slurry is then transferred to a storage tank for use.

[0162] Examples 1-2 Manufacturing of propylene prepolymer slurry 400 kg of hexane and 7 kg of triethylaluminum are added to the catalyst preparation tank, with a mass concentration of 15% triethylaluminum solution. 30 kg of titanium metal catalyst (Beijing Aoda HA-R catalyst) supported by magnesium chloride is added, and the mixture is stirred to form a homogeneous suspension. The temperature of the preparation tank is lowered to below 5°C with frozen brine, and 1400 kg of fresh hexane is added to adjust the concentration of the catalyst slurry. The mixture is then stirred and started until the flow rate reaches 80 r / min. In the first stage of prepolymerization, the automatic gas-phase propylene supply valve is opened, the propylene supply rate is adjusted to 45 kg / h, and the mixture is stirred and started until the flow rate reaches 40 r / min. The temperature of the preparation tank is lowered to 15°C, and prepolymerization is carried out for 1 hour. In the second stage of prepolymerization, the propylene supply rate is adjusted to 55 kg / h, stirred until it reaches 40 r / min, the temperature of the preparation tank is lowered to 35°C, and prepolymerization is carried out until all 100 kg of propylene is consumed to obtain a propylene prepolymer slurry. The prepolymer slurry is then transferred to a storage tank for use.

[0163] Examples 1-3 Manufacturing of propylene prepolymer slurry 500 kg of hexane and 7 kg of triethylaluminum are added to the catalyst preparation tank, with a mass concentration of 15% triethylaluminum solution. 32.5 kg of titanium metal catalyst (Beijing Aoda HA-R catalyst) supported by magnesium chloride is added, and the mixture is stirred to form a homogeneous suspension. The temperature of the preparation tank is lowered to below 5°C with frozen brine, and another 700 kg of fresh hexane is added to adjust the concentration of the catalyst slurry. The mixture is then stirred and started until it reaches 80 r / min. In the first stage of prepolymerization, the automatic gas-phase propylene supply valve is opened, the propylene supply rate is adjusted to 25 kg / h, and the mixture is stirred and started until it reaches 40 r / min. The temperature of the preparation tank is then lowered to 5°C, and prepolymerization is carried out for 1 hour. In the second stage of prepolymerization, the propylene supply rate is adjusted to 30 kg / h, stirred until it reaches 40 r / min, the temperature of the preparation tank is lowered to 12°C, and prepolymerization is carried out until all 100 kg of propylene is consumed to obtain a propylene prepolymer slurry. The prepolymer slurry is then transferred to a storage tank for use.

[0164] Examples 1-4 Manufacturing of propylene prepolymer slurry 550 kg of hexane and 7 kg of triethylaluminum were added to the catalyst preparation tank, with a mass concentration of 15% triethylaluminum solution. 34.5 kg of titanium metal catalyst (Beijing Aoda HA-R catalyst) supported by magnesium chloride was added, and the mixture was stirred to form a homogeneous suspension. The temperature of the preparation tank was lowered to below 5°C with frozen brine, and 1400 kg of fresh hexane was added to adjust the concentration of the catalyst slurry. The mixture was then stirred and started until the flow rate reached 80 r / min. In the first stage of prepolymerization, the automatic gas-phase propylene supply valve was opened, the propylene supply rate was adjusted to 30 kg / h, and the mixture was stirred and started until the flow rate reached 40 r / min. The temperature of the preparation tank was then lowered to 8°C, and prepolymerization was carried out for 1 hour. In the second stage of prepolymerization, the propylene supply rate is adjusted to 30 kg / h, stirred until it reaches 40 r / min, the temperature of the preparation tank is lowered to 15°C, and prepolymerization is carried out until all 100 kg of propylene is consumed to obtain a propylene prepolymer slurry. The prepolymer slurry is then transferred to a storage tank for use.

[0165] Examples 1-5 Manufacturing of propylene prepolymer slurry 500 kg of hexane and 7 kg of triethylaluminum are added to the catalyst preparation tank, with a mass concentration of 15% triethylaluminum solution. 35.5 kg of titanium metal catalyst (Beijing Aoda HA-R catalyst) supported by magnesium chloride is added, and the mixture is stirred to form a homogeneous suspension. The temperature of the preparation tank is lowered to below 5°C with frozen brine, and 1400 kg of fresh hexane is added to adjust the concentration of the catalyst slurry. The mixture is then stirred and started until it reaches 80 r / min. In the first stage of prepolymerization, the gas-phase propylene automatic supply valve is opened, the propylene supply rate is adjusted to 30 kg / h, and the mixture is stirred and started until it reaches 40 r / min. The temperature of the preparation tank is lowered to 10°C, and prepolymerization is carried out for 1 hour. In the second stage of prepolymerization, the propylene supply rate is adjusted to 40 kg / h, stirred until it reaches 40 r / min, the temperature of the preparation tank is lowered to 20°C, and prepolymerization is carried out until all 100 kg of propylene is consumed to obtain a propylene prepolymer slurry. The prepolymer slurry is then transferred to a storage tank for use.

[0166] Examples 1-6 Manufacturing of propylene prepolymer slurry 600 kg of hexane and 7 kg of triethylaluminum are added to the catalyst preparation tank, with a mass concentration of 15% triethylaluminum solution. 34.5 kg of titanium metal catalyst (Beijing Aoda HA-R catalyst) supported by magnesium chloride is added, and the mixture is stirred to form a homogeneous suspension. The temperature of the preparation tank is lowered to below 5°C with frozen brine, and 1400 kg of fresh hexane is added to adjust the concentration of the catalyst slurry. The mixture is then stirred and started until the flow rate reaches 80 r / min. In the first stage of prepolymerization, the automatic gas-phase propylene supply valve is opened, the propylene supply rate is adjusted to 35 kg / h, and the mixture is stirred and started until the flow rate reaches 40 r / min. The temperature of the preparation tank is lowered to 12°C, and prepolymerization is carried out for 1 hour. In the second stage of prepolymerization, the propylene supply rate is adjusted to 40 kg / h, stirred until it reaches 40 r / min, the temperature of the preparation tank is lowered to 18°C, and prepolymerization is carried out until all 100 kg of propylene is consumed to obtain a propylene prepolymer slurry. The prepolymer slurry is then transferred to a storage tank for use.

[0167] Examples 1-7 Manufacturing of propylene prepolymer slurry 500 kg of hexane and 7.2 kg of triethylaluminum were added to the catalyst preparation tank, with a mass concentration of 15% triethylaluminum solution. 36 kg of titanium metal catalyst (Beijing Aoda HA-R catalyst) supported by magnesium chloride was added, and the mixture was stirred to form a homogeneous suspension. The temperature of the preparation tank was lowered to below 5°C with frozen brine, and 1400 kg of fresh hexane was added to adjust the concentration of the catalyst slurry. The mixture was then stirred and started until the flow rate reached 80 r / min. In the first stage of prepolymerization, the automatic gas-phase propylene supply valve was opened, the propylene supply rate was adjusted to 25 kg / h, and the mixture was stirred and started until the flow rate reached 40 r / min. The temperature of the preparation tank was lowered to 14°C, and prepolymerization was carried out for 1 hour. In the second stage of prepolymerization, the propylene supply rate is adjusted to 30 kg / h, stirred until it reaches 40 r / min, the temperature of the preparation tank is lowered to below 20°C, and prepolymerization is carried out until all 100 kg of propylene is consumed to obtain a propylene prepolymer slurry. The prepolymer slurry is then transferred to a storage tank for use.

[0168] Examples 1-8 Manufacturing of propylene prepolymer slurry 550 kg of hexane and 5 kg of triethylaluminum are added to the catalyst preparation tank, with a mass concentration of 15% triethylaluminum solution. 10 kg of titanium metal catalyst (Beijing Aoda HA-R catalyst) supported by magnesium chloride is added, and the mixture is stirred to form a homogeneous suspension. The temperature of the preparation tank is lowered to below 5°C with frozen brine, and 1400 kg of fresh hexane is added to adjust the concentration of the catalyst slurry. The mixture is then stirred and started until it reaches 80 r / min. In the first stage of prepolymerization, the gas-phase propylene automatic supply valve is opened, the propylene supply rate is adjusted to 25 kg / h, and the mixture is stirred and started until it reaches 40 r / min. The temperature of the preparation tank is lowered to 9°C, and prepolymerization is carried out for 1 hour. In the second stage of prepolymerization, the propylene supply rate is adjusted to 30 kg / h, stirred until it reaches 40 r / min, the temperature of the preparation tank is lowered to 16°C, and prepolymerization is carried out until all 100 kg of propylene is consumed to obtain a propylene prepolymer slurry. The prepolymer slurry is then transferred to a storage tank for use.

[0169] The catalyst slurries produced in Examples 1-1 to 1-8 were used in the production of polypropylene in Comparative Examples 1 to 8, respectively, and the most suitable catalyst slurry was selected.

[0170] Example 2 Polypropylene manufacturing method

[0171] Liquid-phase bulk polymerization reaction The catalyst slurry, propylene, co-catalyst, external electron donor, and an appropriate amount of hydrogen gas were added to the first tank reactor to carry out liquid-phase bulk polymerization. The gaseous propylene was refluxed into the reactor via the top condenser. The polymerization temperature was 70°C, the polymerization pressure was 3.0 MPa, the liquid level was 49%, the supply rate of the catalyst slurry produced in Example 1-2 was 14.0 kg / h, the supply rate of propylene was 5.7 t / h, the supply rate of triethylaluminum was 0.8 kg / h, the supply rate of cyclohexylmethyldimethoxysilane was 0.07 kg / h, and the supply rate of hydrogen gas was 4.9 Nm³. 2 The hydrogen gas concentration is 2890 ppm. The reaction slurry flow rate at the outlet is 4.5 t / h.

[0172] The slurry from the outlet of the first-tank reactor was placed in the second-tank reactor to carry out the polymerization reaction. The temperature of the second polymerization tank was 64°C, the polymerization pressure was 2.6 MPa, and the liquid level was 44%. Hydrogen gas was added to the second-tank polymerization reactor, with a hydrogen gas supply rate of 2.0 Nm³. 2 The hydrogen gas concentration is 1300 ppm. The reaction slurry flow rate at the outlet is 4.5 t / h.

[0173] gas-phase polymerization reaction The slurry from the outlet of the second-tank reactor was placed in a gas-phase fluidized bed reactor to carry out the polymerization reaction. The polymerization temperature was 80°C, the polymerization pressure was 1.8 MPa, and the raw material position was 51%.

[0174] Polypropylene drying The material at the outlet of the gas-phase fluidized bed reactor first enters a cyclone separator for gas-solid separation. The separated solid-phase polypropylene powder then enters a dryer where it is dried by convection-driven inert gas at a drying temperature of 105°C.

[0175] Polypropylene Refinement After drying the polypropylene powder with an inert gas, it is transported to a polymer high-purification tank, where a predetermined amount of a composite solvent (hexane and ethanol composite solvent, mass ratio 4:1) is added to form a polymer powder slurry with a slurry concentration of 10%. High-purification of the polymer is then performed under predetermined process conditions (stirring speed 50 rpm, slurry supply speed 20 t / h) at a purification temperature of 30°C and a purification time of 0.1 hours. The highly purified polymer slurry is centrifuged to obtain a polymer wet powder, in which the solvent content is 25%. Further volatile organic compounds are removed through a multi-stage drying process (drying temperature 105°C). Subsequently, it is transported to an extrusion granulation unit to obtain a condenser film ultra-clean polypropylene resin.

[0176] Extrusion granulation A low-ash, long-lasting antioxidant composite additive (containing antioxidant 1010 at 2000 mg / kg, 168 at 1000 mg / kg, and calcium stearate at 80 mg / kg) and dried polypropylene powder are simultaneously added to a twin-screw extruder, and extrusion granulation is performed (granulation temperature at 225°C and screw rotation speed at 120 rpm) to obtain ultra-pure polypropylene resin for condenser films.

[0177] Example 3 The manufacturing process is the same as in Example 2. The differences are as follows: After drying the polypropylene powder with an inert gas, it is transported to a polymer high-purification tank, where a predetermined amount of a composite solvent (hexane and ethanol composite solvent, mass ratio 4:1) is added to form a polymer powder slurry with a slurry concentration of 30%. High-purification of the polymer is then performed under predetermined process conditions, with a purification temperature of 70°C and a purification time of 3 hours. The highly purified polymer slurry is centrifuged to obtain a polymer wet powder, in which the solvent content is 25%, and volatile organic compounds are removed through a multi-stage drying process (drying temperature 105°C). Subsequently, it is transported to an extrusion granulation unit to obtain a condenser film ultra-clean polypropylene resin.

[0178] Example 4 The manufacturing process is the same as in Example 2. The differences are as follows: After drying the polypropylene powder with an inert gas, it is transported to a polymer high-purification tank, where a predetermined amount of a composite solvent (hexane and ethanol composite solvent, mass ratio 4:1) is added to form a polymer powder slurry with a slurry concentration of 40%. High-purification of the polymer is then performed under predetermined process conditions, with a purification temperature of 120°C and a purification time of 5 hours. The highly purified polymer slurry is centrifuged to obtain a polymer wet powder, in which the solvent content is 25%, and volatile organic compounds are removed through a multi-stage drying process (drying temperature 105°C). Subsequently, it is transported to an extrusion granulation unit to obtain a condenser film ultra-clean polypropylene resin.

[0179] Example 5 The manufacturing process is the same as in Example 2. The differences are as follows: After drying the polypropylene powder with an inert gas, it is transported to a polymer high-purification tank, where a predetermined amount of a composite solvent (hexane and ethanol composite solvent, mass ratio 4:1) is added to form a polymer powder slurry with a slurry concentration of 35%. High-purification of the polymer is then performed under predetermined process conditions, with a purification temperature of 60°C and a purification time of 1 hour. The highly purified polymer slurry is centrifuged to obtain a polymer wet powder, in which the solvent content is 25%, and volatile organic compounds are removed through a multi-stage drying process (drying temperature 105°C). Subsequently, it is transported to an extrusion granulation unit to obtain a condenser film ultra-clean polypropylene resin.

[0180] Example 6 The manufacturing process is the same as in Example 2. The differences are as follows: After drying the polypropylene powder with an inert gas, it is transported to a polymer high-purification tank, where a predetermined amount of a composite solvent (hexane and ethanol composite solvent, mass ratio 4:1) is added to form a polymer powder slurry with a slurry concentration of 40%. High-purification of the polymer is then performed under predetermined process conditions, with a purification temperature of 60°C and a purification time of 1 hour. The highly purified polymer slurry is centrifuged to obtain a polymer wet powder, in which the solvent content is 25%, and volatile organic compounds are removed through a multi-stage drying process (drying temperature 105°C). Subsequently, it is transported to an extrusion granulation unit to obtain a condenser film ultra-clean polypropylene resin.

[0181] Example 7 The manufacturing process is the same as in Example 2. The differences are as follows: A low-ash, long-lasting antioxidant composite additive (5000 mg / kg of antioxidant 1010, 1600 mg / kg of antioxidant 168, and 40 mg / kg of calcium stearate) and the dried polypropylene powder are simultaneously added to a twin-screw extruder and extruded and granulated (granulation temperature of 225°C and screw rotation speed of 120 rpm) to obtain a condenser film ultra-pure polypropylene resin.

[0182] Example 8 The manufacturing process is the same as in Example 2. The differences are as follows: A low-ash, long-lasting antioxidant composite additive (10000 mg / kg of antioxidant 1010, 1200 mg / kg of antioxidant 168, and 30 mg / kg of calcium stearate) and the dried polypropylene powder are simultaneously added to a twin-screw extruder and extruded and granulated (granulation temperature of 225°C and screw rotation speed of 120 rpm) to obtain a condenser film ultra-pure polypropylene resin. Performance measurements were performed on the polypropylene resins produced in Examples 2 to 8, and the results are shown in Table 1. [Table 1]

[0183] Example 9 Propylene prepolymerization: 500 kg of hexane and 7 kg of triethylaluminum solution (at a mass concentration of 15% in hexane solvent) are added to the catalyst preparation tank, and 25 kg of titanium metal catalyst supported by magnesium chloride (Beijing Aoda HA-R catalyst) is added. The mixture is stirred to form a homogeneous suspension. The temperature of the preparation tank is lowered to below 5°C with frozen brine, and 1500 kg of fresh hexane is added to adjust the concentration of the catalyst slurry. The mixture is stirred and started until it reaches 80 r / min. In the first stage of prepolymerization, the automatic gas-phase propylene supply valve is opened, the propylene supply rate is adjusted to 10 kg / h, and the mixture is stirred and started until it reaches 40 r / min. The temperature of the preparation tank is lowered to below -5°C, and prepolymerization is carried out for 1 hour. In the second stage of prepolymerization, the propylene supply rate is adjusted to 15 kg / h, stirred until it reaches 40 r / min, the temperature of the preparation tank is lowered to 5°C, and prepolymerization is carried out until all 100 kg of propylene is consumed to obtain a propylene prepolymer slurry. The propylene prepolymer slurry is then transferred to a storage tank for use.

[0184] Liquid phase bulk polymerization: Propylene prepolymer slurry, propylene, co-catalyst, external electron donor, and an appropriate amount of hydrogen gas were added to the first tank reactor to carry out liquid-phase bulk polymerization. The gaseous propylene was refluxed into the reactor via the top condenser. The polymerization temperature was 70°C, the polymerization pressure was 3.0 MPa, the liquid level was 49%, the prepolymer slurry supply rate was 14.0 kg / h, the propylene supply rate was 5.7 t / h, the triethylaluminum solution supply rate was 0.8 kg / h, the 9,9-di(methoxymethyl)fluorene supply rate was 0.07 kg / h, and the hydrogen gas supply rate was 4.9 Nm³. 2 The hydrogen gas concentration is 2890 ppm. The reaction slurry flow rate at the outlet is 4.5 t / h.

[0185] The slurry from the outlet of the first-tank reactor was placed in the second-tank reactor to carry out the polymerization reaction. The temperature of the second polymerization tank was 64°C, the polymerization pressure was 2.6 MPa, and the liquid level was 44%. Hydrogen gas was added to the second-tank polymerization reactor, with a hydrogen gas supply rate of 2.0 Nm³. 2 The hydrogen gas concentration is 1300 ppm at the flow rate. The reaction slurry flow rate at the outlet is 4.5 t / h.

[0186] Gas-phase polymerization: The slurry from the outlet of the second-tank reactor was placed in a gas-phase fluidized bed reactor to carry out the polymerization reaction. The polymerization temperature was 80°C, the polymerization pressure was 1.8 MPa, and the raw material position was 51%.

[0187] Polypropylene drying: The material at the outlet of the gas-phase fluidized bed reactor first enters a cyclone separator for gas-solid separation. The separated solid-phase polypropylene powder then enters a dryer where it is dried by convection nitrogen gas at a drying temperature of 105°C.

[0188] purification: After drying the polypropylene powder with an inert gas, it is transported to a polymer high-purification tank, where a predetermined amount of a composite solvent (hexane and ethanol composite solvent, mass ratio 4:1) is added to form a polymer powder slurry with a slurry concentration of 30%. High-purification of the polymer is then performed under predetermined process conditions (stirring speed 50 rpm, slurry supply speed 20 t / h) at a purification temperature of 60°C for a purification time of 0.5 hours. The highly purified polymer slurry is centrifuged to obtain a polymer wet powder, in which the solvent content is 25%. Further volatile organic compounds are removed through a multi-stage drying process (drying temperature 105°C). Subsequently, it is transported to an extrusion granulation unit to obtain a condenser film ultra-clean polypropylene resin.

[0189] Extrusion granulation: A low-ash, long-lasting antioxidant composite additive (containing antioxidant 1010 at 2000 mg / kg, 168 at 1000 mg / kg, and calcium stearate at 80 mg / kg) and dried polypropylene powder are simultaneously added to a twin-screw extruder, and extrusion granulation is performed (granulation temperature at 225°C and screw rotation speed at 120 rpm) to obtain ultra-pure polypropylene resin for condenser films.

[0190] Example 10 The manufacturing process is the same as in Example 9. The differences are as follows: 400 kg of hexane and 7 kg of triethylaluminum solution are added to the catalyst preparation tank, 30 kg of titanium metal catalyst (Beijing Aoda HA-R catalyst) supported by magnesium chloride is added, and the mixture is stirred to form a homogeneous suspension. The temperature of the preparation tank is lowered to below 5°C with frozen brine, and then 1400 kg of fresh hexane is added to adjust the concentration of the catalyst slurry. The mixture is stirred and started until it reaches 80 r / min. In the first stage of prepolymerization, the gas-phase propylene automatic supply valve is opened, the propylene supply rate is adjusted to 45 kg / h, the mixture is stirred and started until it reaches 40 r / min, the temperature of the preparation tank is lowered to 15°C, and prepolymerization is carried out for 1 hour. In the second stage of prepolymerization, the propylene supply rate is adjusted to 55 kg / h, the mixture is stirred and started until it reaches 40 r / min, the temperature of the preparation tank is lowered to 35°C, and prepolymerization is carried out until all 100 kg of propylene is consumed to obtain a propylene prepolymer slurry. The above prepolymer slurry is then transferred to a storage tank for use.

[0191] Example 11 The manufacturing process is the same as in Example 9. The differences are as follows: 500 kg of hexane and 7 kg of triethylaluminum solution are added to the catalyst preparation tank, 32.5 kg of titanium metal catalyst (Beijing Aoda HA-R catalyst) supported by magnesium chloride is added, and the mixture is stirred to form a homogeneous suspension. The temperature of the preparation tank is lowered to below 5°C with frozen brine, and another 700 kg of fresh hexane is added to adjust the concentration of the catalyst slurry. The mixture is stirred and started until it reaches 80 r / min. In the first stage of prepolymerization, the gas-phase propylene automatic supply valve is opened, the propylene supply rate is adjusted to 25 kg / h, the mixture is stirred and started until it reaches 40 r / min, the temperature of the preparation tank is lowered to 5°C, and prepolymerization is carried out for 1 hour. In the second stage of prepolymerization, the propylene supply rate is adjusted to 30 kg / h, the mixture is stirred and started until it reaches 40 r / min, the temperature of the preparation tank is lowered to 12°C, and prepolymerization is carried out until all 100 kg of propylene is consumed to obtain a propylene prepolymer slurry. The above prepolymer slurry is then transferred to a storage tank for use.

[0192] Example 12 The manufacturing process is the same as in Example 9. The differences are as follows: 550 kg of hexane and 7 kg of triethylaluminum solution are added to the catalyst preparation tank, 34.5 kg of titanium metal catalyst (Beijing Aoda HA-R catalyst) supported by magnesium chloride is added, and the mixture is stirred to form a homogeneous suspension. The temperature of the preparation tank is lowered to below 5°C with frozen brine, and then 1400 kg of fresh hexane is added to adjust the concentration of the catalyst slurry. The mixture is stirred and started until it reaches 80 r / min. In the first stage of prepolymerization, the gas-phase propylene automatic supply valve is opened, the propylene supply rate is adjusted to 30 kg / h, the mixture is stirred and started until it reaches 40 r / min, the temperature of the preparation tank is lowered to 8°C, and prepolymerization is carried out for 1 hour. In the second stage of prepolymerization, the propylene supply rate is adjusted to 30 kg / h, the mixture is stirred and started until it reaches 40 r / min, the temperature of the preparation tank is lowered to 15°C, and prepolymerization is carried out until all 100 kg of propylene is consumed to obtain a propylene prepolymer slurry. The above prepolymer slurry is then transferred to a storage tank for use.

[0193] Example 13 The manufacturing process is the same as in Example 9. The differences are as follows: 500 kg of hexane and 7 kg of triethylaluminum solution are added to the catalyst preparation tank, 35.5 kg of titanium metal catalyst (Beijing Aoda HA-R catalyst) supported by magnesium chloride is added, and the mixture is stirred to form a homogeneous suspension. The temperature of the preparation tank is lowered to below 5°C with frozen brine, and then 1400 kg of fresh hexane is added to adjust the concentration of the catalyst slurry. The mixture is stirred and started until it reaches 80 r / min. In the first stage of prepolymerization, the gas-phase propylene automatic supply valve is opened, the propylene supply rate is adjusted to 30 kg / h, the mixture is stirred and started until it reaches 40 r / min, the temperature of the preparation tank is lowered to 10°C, and prepolymerization is carried out for 1 hour. In the second stage of prepolymerization, the propylene supply rate is adjusted to 40 kg / h, the mixture is stirred and started until it reaches 40 r / min, the temperature of the preparation tank is lowered to 20°C, and prepolymerization is carried out until all 100 kg of propylene is consumed to obtain a propylene prepolymer slurry. The above prepolymer slurry is then transferred to a storage tank for use.

[0194] Example 14 The manufacturing process is the same as in Example 9. The differences are as follows: 600 kg of hexane and 7 kg of triethylaluminum solution are added to the catalyst preparation tank, 34.5 kg of titanium metal catalyst (Beijing Aoda HA-R catalyst) supported by magnesium chloride is added, and the mixture is stirred to form a homogeneous suspension. The temperature of the preparation tank is lowered to below 5°C with frozen brine, and then 1400 kg of fresh hexane is added to adjust the concentration of the catalyst slurry. The mixture is stirred and started until it reaches 80 r / min. In the first stage of prepolymerization, the gas-phase propylene automatic supply valve is opened, the propylene supply rate is adjusted to 35 kg / h, the mixture is stirred and started until it reaches 40 r / min, the temperature of the preparation tank is lowered to 12°C, and prepolymerization is carried out for 1 hour. In the second stage of prepolymerization, the propylene supply rate is adjusted to 40 kg / h, the mixture is stirred and started until it reaches 40 r / min, the temperature of the preparation tank is lowered to 18°C, and prepolymerization is carried out until all 100 kg of propylene is consumed to obtain a propylene prepolymer slurry. The above prepolymer slurry is then transferred to a storage tank for use.

[0195] Example 15 The manufacturing process is the same as in Example 9. The differences are as follows: 500 kg of hexane and 7.2 kg of triethylaluminum solution are added to the catalyst preparation tank, 36 kg of titanium metal catalyst (Beijing Aoda HA-R catalyst) supported by magnesium chloride is added, and the mixture is stirred to form a homogeneous suspension. The temperature of the preparation tank is lowered to below 5°C with frozen brine, and then 1400 kg of fresh hexane is added to adjust the concentration of the catalyst slurry. The mixture is stirred and started until it reaches 80 r / min. In the first stage of prepolymerization, the gas-phase propylene automatic supply valve is opened, the propylene supply rate is adjusted to 25 kg / h, the mixture is stirred and started until it reaches 40 r / min, the temperature of the preparation tank is lowered to 14°C, and prepolymerization is carried out for 1 hour. In the second stage of prepolymerization, the propylene supply rate is adjusted to 30 kg / h, the mixture is stirred and started until it reaches 40 r / min, the temperature of the preparation tank is lowered to below 20°C, and prepolymerization is carried out until all 100 kg of propylene is consumed to obtain a propylene prepolymer slurry. The above prepolymer slurry is then transferred to a storage tank for use.

[0196] Example 16 The manufacturing process is the same as in Example 9. The differences are as follows: 550 kg of hexane and 5 kg of triethylaluminum solution are added to the catalyst preparation tank, 10 kg of titanium metal catalyst (Beijing Aoda HA-R catalyst) supported by magnesium chloride is added, and the mixture is stirred to form a homogeneous suspension. The temperature of the preparation tank is lowered to below 5°C with frozen brine, and then 1400 kg of fresh hexane is added to adjust the concentration of the catalyst slurry. The mixture is stirred and started until it reaches 80 r / min. In the first stage of prepolymerization, the gas-phase propylene automatic supply valve is opened, the propylene supply rate is adjusted to 25 kg / h, the mixture is stirred and started until it reaches 40 r / min, the temperature of the preparation tank is lowered to 9°C, and prepolymerization is carried out for 1 hour. In the second stage of prepolymerization, the propylene supply rate is adjusted to 30 kg / h, the mixture is stirred and started until it reaches 40 r / min, the temperature of the preparation tank is lowered to 16°C, and prepolymerization is carried out until all 100 kg of propylene is consumed to obtain a propylene prepolymer slurry. The above prepolymer slurry is then transferred to a storage tank for use.

[0197] Performance measurements were performed on the polypropylene resins produced in Examples 9 to 16, and the results are shown in Table 2. [Table 2]

[0198] Comparative Example 1 Polypropylene manufacturing method

[0199] Liquid-phase bulk polymerization reaction The catalyst slurry, propylene, co-catalyst, external electron donor, and an appropriate amount of hydrogen gas were added to the first tank reactor to carry out liquid-phase bulk polymerization. The gaseous propylene was refluxed into the reactor via the top condenser. The polymerization temperature was 70°C, the polymerization pressure was 3.0 MPa, the liquid level was 49%, the supply rate of the catalyst slurry produced in Example 1-1 was 15.0 kg / h, the supply rate of propylene was 5.7 t / h, the supply rate of triethylaluminum was 0.8 kg / h, the supply rate of cyclohexylmethyldimethoxysilane was 0.07 kg / h, and the supply rate of hydrogen gas was 4.9 Nm³. 2 The value is / h, and the hydrogen gas concentration is 1000 ppm.

[0200] The slurry from the outlet of the first-tank reactor was placed in the second-tank reactor to carry out the polymerization reaction. The temperature of the second polymerization tank was 64°C, the polymerization pressure was 2.6 MPa, and the liquid level was 44%. Hydrogen gas was added to the second-tank polymerization reactor, with a hydrogen gas supply rate of 2.0 Nm³. 2 The value is / h, and the hydrogen gas concentration is 1300 ppm.

[0201] gas-phase polymerization reaction The slurry from the outlet of the second-tank reactor was placed in a gas-phase fluidized bed reactor to carry out the polymerization reaction. The polymerization temperature was 80°C, the polymerization pressure was 1.8 MPa, and the raw material position was 51%.

[0202] Polypropylene drying The material at the outlet of the gas-phase fluidized bed reactor first enters a cyclone separator for gas-solid separation. The separated solid-phase polypropylene powder then enters a dryer where it is dried by convection-driven inert gas at a drying temperature of 105°C.

[0203] Extrusion granulation A low-ash, long-lasting antioxidant composite additive and dried polypropylene powder are simultaneously added to a twin-screw extruder and extruded to produce ultra-pure polypropylene resin for condenser films.

[0204] Comparative Example 2 The manufacturing process is the same as in Comparative Example 1. The difference is that the catalyst slurry produced in Example 1-2 was used, the supply rate of the catalyst slurry in the first tank reactor was 11.0 kg / h, the supply rate of propylene was 5.7 t / h, the supply rate of triethylaluminum was 0.57 kg / h, and the supply rate of hydrogen gas was 4.9 Nm³. 2 The key points are that the hydrogen gas concentration is 3000 ppm, and the rate is / h.

[0205] Comparative Example 3 The manufacturing process is the same as in Comparative Example 1. The difference lies in the use of the catalyst slurry produced in Examples 1-3, with a feed rate of 14.5 kg / h.

[0206] Comparative Example 4 The manufacturing process is the same as in Comparative Example 1. The difference lies in the use of the catalyst slurry produced in Examples 1-4, with a feed rate of 16.2 kg / h.

[0207] Comparative Example 5 The manufacturing process is the same as in Comparative Example 1. The difference lies in the use of the catalyst slurry produced in Examples 1-5, with a feed rate of 16.3 kg / h.

[0208] Comparative Example 6 The manufacturing process is the same as in Comparative Example 1. The difference lies in the use of the catalyst slurry produced in Examples 1-6, with a feed rate of 16.0 kg / h.

[0209] Comparative Example 7 The manufacturing process is the same as in Comparative Example 1. The difference lies in the use of the catalyst slurry produced in Examples 1-7, with a feed rate of 15.8 kg / h.

[0210] Comparative Example 8 The manufacturing process is the same as in Comparative Example 1. The difference lies in the use of the catalyst slurry produced in Examples 1-8, with a feed rate of 15.6 kg / h.

[0211] Performance measurements were performed on the polypropylene resins produced in Comparative Examples 1 to 8, and the results are shown in Table 3. [Table 3]

[0212] Comparative Example 9 Propylene prepolymerization: 500 kg of hexane and 7 kg of triethylaluminum solution are added to the catalyst preparation tank, and 25 kg of titanium metal catalyst (Beijing Aoda HA-R catalyst) supported by magnesium chloride is added. The mixture is stirred to form a homogeneous suspension. The temperature of the preparation tank is lowered to below 5°C with frozen brine, and 1500 kg of fresh hexane is added to adjust the concentration of the catalyst slurry. The mixture is stirred and started until it reaches 80 r / min. In the first stage of prepolymerization, the gas-phase propylene automatic supply valve is opened, the propylene supply rate is adjusted to 15 kg / h, and the mixture is stirred and started until it reaches 40 r / min. The temperature of the preparation tank is lowered to 5°C, and prepolymerization is carried out until all 100 kg of propylene is consumed to obtain a propylene prepolymer slurry. The above propylene prepolymer slurry is then transferred to a storage tank for use.

[0213] Liquid phase bulk polymerization: Propylene prepolymer slurry, propylene, co-catalyst, external electron donor, and an appropriate amount of hydrogen gas were added to the first tank reactor to carry out liquid-phase bulk polymerization. The gaseous propylene was refluxed into the reactor via a top-of-tank cooler. The polymerization temperature was 70°C, the polymerization pressure was 3.0 MPa, the liquid level was 49%, the supply rate of propylene prepolymer slurry was 14.0 kg / h, the supply rate of propylene was 5.7 t / h, the supply rate of triethylaluminum was 0.8 kg / h, the supply rate of 9,9-di(methoxymethyl)fluorene was 0.07 kg / h, and the supply rate of hydrogen gas was 4.9 Nm³. 2 The hydrogen gas concentration is 2890 ppm. The reaction slurry flow rate at the outlet is 4.5 t / h.

[0214] The slurry from the outlet of the first-tank reactor was placed in the second-tank reactor to carry out the polymerization reaction. The temperature of the second polymerization tank was 64°C, the polymerization pressure was 2.6 MPa, and the liquid level was 44%. Hydrogen gas was added to the second-tank polymerization reactor, with a hydrogen gas supply rate of 2.0 Nm³. 2 The hydrogen gas concentration is 1300 ppm. The reaction slurry flow rate at the outlet is 4.5 t / h.

[0215] Gas-phase polymerization: The slurry from the outlet of the second-tank reactor was placed in a gas-phase fluidized bed reactor to carry out the polymerization reaction. The polymerization temperature was 80°C, the polymerization pressure was 1.8 MPa, and the raw material position was 51%.

[0216] Polypropylene drying: The material at the outlet of the gas-phase fluidized bed reactor first enters a cyclone separator for gas-solid separation. The separated solid-phase polypropylene powder then enters a dryer where it is dried by convection nitrogen gas at a drying temperature of 105°C.

[0217] Polypropylene purification: After drying the polypropylene powder with nitrogen gas, it is transported to a polymer high-purification tank, where a predetermined amount of a composite solvent (hexane and ethanol composite solvent, mass ratio 4:1) is added to form a polymer powder slurry with a slurry concentration of 30%. High-purification of the polymer is then performed under predetermined process conditions (stirring speed 50 rpm, slurry supply speed 20 t / h) at a purification temperature of 60°C for a purification time of 0.5 hours. The highly purified polymer slurry is centrifuged to obtain a polymer wet powder, in which the solvent content is 25%. Further volatile organic compounds are removed through a multi-stage drying process (drying temperature 105°C). Subsequently, it is transported to an extrusion granulation unit to obtain a condenser film ultra-clean polypropylene resin.

[0218] Extrusion granulation: A low-ash, long-lasting antioxidant composite additive (containing antioxidant 1010 at 2000 mg / kg, 168 at 1000 mg / kg, and calcium stearate at 80 mg / kg) and dried polypropylene powder are simultaneously added to a twin-screw extruder, and extrusion granulation is performed (granulation temperature at 225°C and screw rotation speed at 120 rpm) to obtain ultra-pure polypropylene resin for condenser films.

[0219] Comparative Example 10 The manufacturing process is the same as in Comparative Example 9, except that there is no propylene prepolymerization.

[0220] Comparative Example 11 The manufacturing process is the same as in Comparative Example 10. The difference lies in the supply rate of the propylene prepolymer slurry, which is 15.0 kg / h.

[0221] Comparative Example 12 The manufacturing process is the same as in Comparative Example 10. The difference lies in the supply rate of the propylene prepolymer slurry, which is 16.0 kg / h.

[0222] Comparative Example 13 The manufacturing process is the same as in Comparative Example 10. The difference lies in the supply rate of the propylene prepolymer slurry, which is 17.0 kg / h.

[0223] Performance measurements were performed on the polypropylene resins produced in Comparative Examples 9 to 13, and the results are shown in Table 4. [Table 4]

[0224] As can be seen from Tables 2 and 4, adding a propylene prepolymerization process before liquid-phase bulk polymerization significantly reduces the ash content of the produced polypropylene resin, improves the electrical properties of the resin, and significantly reduces the fine powder content of the polypropylene powder, which is advantageous for stable operation of the apparatus.

[0225] The above embodiments of the present invention are merely examples given to clearly explain the present invention and do not limit the embodiments of the present invention. Those skilled in the art can make other different forms of changes or modifications based on the above description. It is impossible to cover all the embodiments here, and all obvious changes or modifications derived from the technical solution of the present invention are also within the protection scope of the present invention. <Note> This disclosure includes the following aspects: <Section 1> A manufacturing method comprising propylene prepolymerization, liquid-phase bulk polymerization, gas-phase polymerization, polypropylene drying, purification, and extrusion granulation, Propylene prepolymerization: After preparing a catalyst slurry containing a main catalyst, a co-catalyst, and a solvent in a prepolymerization reactor, propylene is introduced to carry out a prepolymerization reaction to obtain a prepolymer slurry; Liquid phase bulk polymerization: Using propylene as a raw material, a polymerization reaction is carried out in the presence of the prepolymer slurry, a co-catalyst, an external electron donor, and hydrogen gas to obtain a crude polypropylene slurry, wherein the external electron donor is 9,9-di(methoxymethyl)fluorene; Gas-phase polymerization: The crude polypropylene slurry obtained by liquid-phase bulk polymerization is placed in a gas-phase fluidized bed reactor to carry out the polymerization reaction; Polypropylene drying: The outlet material of a gas-phase fluidized bed reactor is first subjected to gas-solid separation, and the solid phase component is dried in a dryer to obtain polypropylene powder. purification: Dried polypropylene powder is prepared into a slurry with a composite solvent, stirred and purified, then the slurry is subjected to solid-liquid separation to obtain wet polypropylene powder, which is then dried to obtain ultra-clean polypropylene powder; Extrusion granulation: After mixing the purified ultra-clean polypropylene powder with an antioxidant compound additive, the mixture is extruded and granulated to obtain the ultra-clean polypropylene resin. A method for producing ultra-clean polypropylene resin, characterized by the following features. <Section 2> The manufacturing method according to item 1, characterized in that the prepolymerization reaction comprises a first stage in which the prepolymerization temperature is -5°C to 15°C, the propylene supply rate is 10 to 45 kg / h, and the prepolymerization time is 0.5 to 3 h, and a second stage in which the prepolymerization temperature is 5°C to 35°C, the propylene supply rate is 15 to 55 kg / h, and until all of the propylene for prepolymerization is added to the prepolymerization reactor. <Section 3> The manufacturing method according to item 1 or item 2, characterized in that, in the propylene prepolymerization process, the mass ratio of propylene to the main catalyst is 2.5 to 10 kg / kg, and the mass ratio of the co-catalyst to the main catalyst is 0.027 to 0.075 kg / kg. <Section 4> The manufacturing method according to item 1, characterized in that the solvent in the catalyst slurry is one or more selected from butane, pentane, hexane, heptane, octane, nonane, and decane. <​​​​​​​​​​​​​​​​ <Section 8> The manufacturing method according to item 1 or item 7, characterized in that, in the liquid-phase bulk polymerization process, the mass ratio of the main catalyst to propylene is 0.03 to 0.05 kg / t, the mass ratio of the co-catalyst to propylene is 0.015 to 0.0225 kg / t, and the mass ratio of the external electron donor to the co-catalyst is 0 to 0.015 kg / kg, not including 0. <Section 9> The manufacturing method according to item 1, characterized in that, in the gas-phase polymerization process, the polymerization temperature is 75 to 85°C, the polymerization pressure is 1.5 to 2.0 MPa, the melt flow rate of the polypropylene powder at the outlet of the gas-phase fluidized bed reactor is 2.8 to 3.2 g / 10 min, the ash content is less than 30 ppm, and the isotacticity is greater than 98.5%. <Section 10> The manufacturing method according to item 1, characterized in that, in the polypropylene drying process, the solid phase component is placed in a drying oven and dried by convection nitrogen gas, and the drying temperature is 100 to 110°C. <Section 11> The manufacturing method according to item 1, characterized in that the purification temperature is 30 to 150°C and the time is 0.1 to 5 hours. <Section 12> The manufacturing method according to item 1, characterized in that, with the total mass of the polypropylene powder being 100%, the proportion of the solvent in the wet polypropylene powder is 15 to 35%. <Section 13> The manufacturing method according to item 1, characterized in that, in the purification process, the mass concentration of polypropylene powder in the prepared slurry is 10 to 40%. <Section 14> The manufacturing method according to item 1, characterized in that the ash content of the ultra-clean polypropylene powder is less than 10 ppm. <Section 15> The manufacturing method according to item 1, characterized in that the composite solvent comprises a hydrocarbon substance and an alkyl alcohol, the hydrocarbon substance being selected from pentane, hexane, heptane, octane, nonane, or decane, the alkyl alcohol being selected from methanol, ethanol, propanol, or butanol, and the mass ratio of the hydrocarbon substance to the alkyl alcohol being (2-6):1. <Section 16> The manufacturing method according to item 1, characterized in that the ash content of the ultraclean polypropylene resin obtained by the extrusion granulation is less than 20 ppm. <Section 17> The antioxidant complex additive includes an acid scavenger, a main antioxidant, and an auxiliary antioxidant. The acid scavenger is one or more types selected from metal stearates and hydrotalcite, and the mass ratio of the ultra-clean polypropylene powder to the acid scavenger is (10000~100000):1. The main antioxidant is one or a combination of several selected from pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid], 1,3,5-tris(3,5-di-tert-butyl-4-hydroxybenzyl)-S-triazine-2,4,6-(1H,3H,5H)trione, β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid stearyl, 1,3,5-trimethyl-2,4,6-tris(3,5-di-tert-butyl-4-hydroxybenzyl)benzene, and 1,1,3-tris(2-methyl-4-hydroxy-5-tert-butylphenyl)butane, and the mass ratio of the ultra-clean polypropylene powder to the main antioxidant is (1000~10000):1. The manufacturing method according to item 1, characterized in that the auxiliary antioxidant is one or a combination of several selected from dilauryl thiodipropionate, distearyl thiodipropionate, dimyristyl thiodipropionate, tris(nonylphenyl) phosphite, bis(octadecyl)pentaerythritol diphosphite, tris(2,4-t-butylphenyl) phosphite, and bis(2,4-di-tert-butylphenyl)pentaerythritol diphosphite, and the mass ratio of the ultra-clean polypropylene powder to the auxiliary antioxidant is (100~10000):1. <Section 18> An ultra-clean polypropylene resin manufactured by the manufacturing method described in any one of items <1> to <17>. <Section 19> A step of polymerizing propylene as a raw material to obtain a crude polypropylene product, A method comprising the step of purifying the obtained crude polypropylene product to obtain the polypropylene resin, The purification method comprises adding crude polypropylene to a composite solvent, thoroughly contacting the crude polypropylene with the composite solvent at 30 to 120°C to form a polypropylene slurry, separating the polypropylene from the composite solvent to obtain polypropylene powder, and drying the polypropylene powder to obtain the polypropylene resin. <Section 20> The manufacturing method according to item 19, wherein the composite solvent is a mixed solvent selected from at least one alkyl alcohol having 1 to 10 carbon atoms and at least one alkane having 5 to 20 carbon atoms that is liquid at room temperature. <Section 21> The manufacturing method according to item 19 or 20, wherein the aforementioned sufficient contact comprises contacting the crude polypropylene product with the composite solvent for 0.1 to 5 hours under stirring conditions. <Section 22> The manufacturing method according to any one of items 19 to 21, wherein the mass concentration of polypropylene in the polypropylene slurry is 10 to 40%. <Section 23> The manufacturing method according to any one of items 19 to 22, wherein the purification includes separating polypropylene from a composite solvent by centrifugation to obtain polypropylene powder, and then drying the polypropylene powder at 95 to 120°C to obtain the polypropylene resin. <Section 24> The method for manufacturing according to any one of items 19 to 23, further comprising the step of mixing the obtained polypropylene resin with an antioxidant composite additive and then extruding and granulating it. <Section 25> The aforementioned antioxidant complex additive is a combination selected from an acid scavenger, a main antioxidant, and an auxiliary antioxidant, the acid scavenger being a combination of one or more selected from metal stearates and hydrotalcite, the main antioxidant being pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid], 1,3,5-tris(3,5-di-tert-butyl-4-hydroxybenzyl)-S-triazine-2,4,6-(1H,3H,5H)trione, β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid stearyl, 1,3,5-trimethyl-2,4,6-tris(3,5-di-tert-butyl-4-hydroxybenzyl)benzene, and 1,1,3-tris(2-methyl The manufacturing method according to item 24, wherein the antioxidant is one or a combination of several selected from (2,4-hydroxy-5-tert-butylphenyl)butane, and the auxiliary antioxidant is one or a combination of several selected from dilauryl thiodipropionate, distearyl thiodipropionate, dimyristyl thiodipropionate, tris(nonylphenyl) phosphite, bis(octadecyl)pentaerythritol diphosphite, tris(2,4-t-butylphenyl)phosphite and bis(2,4-di-tert-butylphenyl)pentaerythritol diphosphite, and with the total mass of the antioxidant complex auxiliary being 100%, the mass percentage content of the acid scavenger, main antioxidant and auxiliary antioxidant is 0.1-1%, 65-90%, and 9.4-34.4%, respectively. <Section 26> The manufacturing method according to item 24 or item 25, wherein the mass percentage content of the antioxidant composite additive is 0.2% to 1%, with the mass of the obtained polypropylene resin being 100%. <Section 27> The step of polymerizing using propylene as a raw material includes the following steps: Propylene prepolymerization step: This step involves polymerizing a predetermined amount of propylene in the presence of a main catalyst and a co-catalyst to form a thin polypropylene layer on the surface of catalyst particles and to obtain a prepolymer slurry, wherein the mass ratio of propylene to the main catalyst in the prepolymerization step is 2.5 to 10 kg / kg, and the mass ratio of the co-catalyst to the main catalyst in the prepolymerization step is 0.18 to 0.5 kg / kg; Polymerization step: Using propylene as a raw material, a polymerization reaction is carried out in the presence of the prepolymer slurry, a co-catalyst, an external electron donor, and hydrogen gas to obtain a crude polypropylene product. The manufacturing method described in any one of items 19 to 26. <Section 28> The production method according to item 27, wherein the propylene prepolymerization step includes introducing propylene at a rate of 10 to 45 kg / h in the presence of a main catalyst and a co-catalyst, polymerizing at -5°C to 15°C for 0.5 to 3 hours, and then introducing propylene at a rate of 15 to 55 kg / h until all the remaining propylene is added to the prepolymerization reactor, and polymerizing at 5°C to 35°C. <Section 29> The manufacturing method according to item 19 or item 28, comprising a propylene prepolymerization step in which a main catalyst is added to a linear or branched alkane having 4 to 10 carbon atoms, the mass concentration of the main catalyst in the alkane solution being 0.1 to 3%, and further adding propylene and a co-catalyst to carry out the polymerization reaction. <Section 30> The manufacturing method according to any one of items 27 to 29, wherein the mass ratio of the main catalyst to the propylene added in the polymerization step is 0.03 to 0.05 kg / t, the mass ratio of the co-catalyst added in the polymerization step to the propylene added in the polymerization step is 0.1 to 0.15 kg / t, and the mass ratio of the external electron donor to the co-catalyst added in the polymerization step is 0 to 0.1 kg / kg. <Section 31> The polymerization step includes the following steps: Liquid-phase bulk polymerization step: This step includes carrying out liquid-phase bulk polymerization using propylene as a raw material in the presence of the prepolymer slurry, co-catalyst, external electron donor, and hydrogen gas at a temperature of 60°C to 75°C and a pressure of 2.5 to 3.5 MPa; The gas-phase polymerization step includes carrying out gas-phase polymerization of the slurry obtained by liquid-phase bulk polymerization at a temperature of 75°C to 85°C and a pressure of 1.5 to 2.0 MPa to obtain a crude polypropylene product. The manufacturing method described in any one of items 27 to 30. <Section 32> The manufacturing method according to item 31, wherein the liquid-phase bulk polymerization step includes adding propylene, a prepolymer slurry, a co-catalyst, an external electron donor, and hydrogen gas to a first reaction vessel, carrying out a polymerization reaction at a temperature of 60°C to 75°C and a pressure of 2.5 to 3.5 MPa, the flow rate of the reaction slurry at the outlet of the first reaction vessel being 4.0 to 4.5 g / 10 min, and the hydrogen gas concentration in the first reaction vessel being 1000 to 3000 ppm; and thereafter adding the reaction slurry to a second reaction vessel, introducing hydrogen gas, and carrying out a polymerization reaction at a temperature of 60°C to 75°C and a pressure of 2.5 to 3.5 MPa, the flow rate of the reaction slurry at the outlet of the second reaction vessel being 3.5 to 4.5 g / 10 min, and the hydrogen gas concentration in the second reaction vessel being 1000 to 2000 ppm. <Section 33> A manufacturing method according to any one of items 19 to 32, wherein the step of polymerizing propylene as a raw material further comprises the step of drying the solid obtained after the polymerization reaction at 95°C to 115°C, thereby obtaining a crude polypropylene product. <Section 34> The manufacturing method according to any one of claims 19 to 33, wherein the main catalyst is a Zn-based catalyst, the co-catalyst is an alkylaluminum compound, and the external electron donor is one or a combination of several selected from cyclohexyldimethoxymethylsilane, p-dicyclopentyldimethoxysilane, diisopropyldimethoxysilane, and diisobutyldimethoxysilane. <Section 35> The aforementioned Zn-based catalyst is MgCl 2 Using TiCl as a support, 4 The method for producing a catalyst as described in item 34, wherein the catalyst has as an active center and one or more catalysts selected from alkyl-substituted 1,3-diethers, aryl-substituted 1,3-diethers, succinic acid esters, and malonic acid esters as internal electron donors. <Section 36> The method for producing the alkylaluminum compound according to item 34, wherein the alkylaluminum compound is one or more combinations selected from trialkylaluminum, alkylaluminoxane, a combination of trialkylaluminum and alkylaluminum halide, or a combination of trialkylaluminum and alkylaluminum hydride. <Section 37> Polypropylene resin manufactured by the manufacturing method described in any one of items 19 to 36. <Section 38> The polypropylene resin is a polypropylene resin obtained by extruding granulation after mixing with an antioxidant composite additive, and the ash content is 30 ppm or less, as described in item 37.

Claims

1. A manufacturing method comprising propylene prepolymerization, liquid-phase bulk polymerization, gas-phase polymerization, polypropylene drying, purification, and extrusion granulation, Propylene prepolymerization: After preparing a catalyst slurry containing a main catalyst, a co-catalyst, and a solvent in a prepolymerization reactor, propylene is introduced to carry out a prepolymerization reaction to obtain a prepolymer slurry; the prepolymerization reaction comprises a first stage in which the prepolymerization temperature is -5°C to 10°C, the propylene supply rate is 10 to 45 kg / h, and the prepolymerization time is 0.5 to 3 hours; and a second stage in which the prepolymerization temperature is 12°C to 35°C, the propylene supply rate is 15 to 55 kg / h, and all of the propylene for prepolymerization is added to the prepolymerization reactor; Liquid phase bulk polymerization: Using propylene as a raw material, a polymerization reaction is carried out in the presence of the prepolymer slurry, a co-catalyst, an external electron donor, and hydrogen gas to obtain a crude polypropylene slurry, wherein the external electron donor is 9,9-di(methoxymethyl)fluorene; Gas-phase polymerization: The crude polypropylene slurry obtained by liquid-phase bulk polymerization is placed in a gas-phase fluidized bed reactor to carry out the polymerization reaction; Polypropylene drying: The outlet material of a gas-phase fluidized bed reactor is first subjected to gas-solid separation, and the solid phase component is dried in a dryer to obtain polypropylene powder; purification: Dried polypropylene powder is prepared into a slurry with a composite solvent, stirred and purified, then the slurry is subjected to solid-liquid separation to obtain wet polypropylene powder, which is then dried to obtain ultra-clean polypropylene powder; Extrusion granulation: After mixing purified ultra-clean polypropylene powder with an antioxidant compound additive, the mixture is extruded and granulated to obtain ultra-clean polypropylene resin. A method for producing ultra-clean polypropylene resin, characterized by the following features.

2. The manufacturing method according to claim 1, characterized in that, in the propylene prepolymerization, the mass ratio of propylene to the main catalyst is 2.5 to 10 kg / kg, and the mass ratio of the co-catalyst to the main catalyst is 0.027 to 0.075 kg / kg.

3. The manufacturing method according to claim 1, characterized in that the solvent in the catalyst slurry is one or more selected from butane, pentane, hexane, heptane, octane, nonane, and decane.

4. The main catalyst is MgCl 2 Carpenter, TiCl 4 The method for producing a catalyst according to claim 1, characterized in that it is a Zn-based catalyst comprising an active center and an internal electron donor, wherein the internal electron donor is one or more selected from alkyl-substituted 1,3-diethers, aryl-substituted 1,3-diethers, succinic acid esters, malonic acid esters, and diol esters, and the co-catalyst is an alkylaluminum compound.

5. The liquid-phase bulk polymerization described above includes the following steps: Propylene, prepolymer slurry, co-catalyst, external electron donor, and hydrogen gas are added to the first reaction vessel, and the polymerization reaction is carried out at a temperature of 60°C to 75°C and a pressure of 2.5 to 3.5 MPa. The flow rate of the reaction slurry at the outlet of the first reaction vessel is 4.0 to 4.5 g / 10 min, and the hydrogen gas concentration in the first reaction vessel is 1000 to 3000 ppm. Subsequently, the reaction slurry is added to the second reaction vessel, hydrogen gas is introduced, and the polymerization reaction is carried out at a temperature of 60°C to 75°C and a pressure of 2.5 to 3.5 MPa. The manufacturing method according to claim 1, characterized in that the flow rate of the reaction slurry at the outlet is 3.5 to 4.5 g / 10 min, the hydrogen gas concentration in the second reaction vessel is 1000 to 2000 ppm, in the gas-phase polymerization the polymerization temperature is 75 to 85°C, the polymerization pressure is 1.5 to 2.0 MPa, the melt flow rate of the polypropylene powder at the outlet of the gas-phase fluidized bed reactor is 2.8 to 3.2 g / 10 min, the ash content is less than 30 ppm, and the isotacticity is greater than 98.5%.

6. The manufacturing method according to claim 1, characterized in that, in the liquid-phase bulk polymerization, the mass ratio of the main catalyst to propylene is 0.03 to 0.05 kg / t, the mass ratio of the co-catalyst to propylene is 0.015 to 0.0225 kg / t, and the mass ratio of the external electron donor to the co-catalyst is 0 to 0.015 kg / kg, not including 0.

7. The manufacturing method according to claim 1, characterized in that the purification temperature is 30 to 150°C and the time is 0.1 to 5 hours.

8. The manufacturing method according to claim 1, characterized in that, in the purification process, the mass concentration of polypropylene powder in the prepared slurry is 10 to 40%.

9. The manufacturing method according to claim 1, characterized in that the composite solvent comprises a hydrocarbon substance and an alkyl alcohol, the hydrocarbon substance being selected from pentane, hexane, heptane, octane, nonane, or decane, the alkyl alcohol being selected from methanol, ethanol, propanol, or butanol, and the mass ratio of the hydrocarbon substance to the alkyl alcohol being (2-6):

1.

10. The manufacturing method according to claim 1, characterized in that the ash content of the ultra-clean polypropylene resin obtained by the extrusion granulation is less than 20 ppm.

11. The antioxidant complex additive includes an acid scavenger, a main antioxidant, and an auxiliary antioxidant. The acid scavenger is one or more types selected from metal stearates and hydrotalcite, and the mass ratio of the ultra-clean polypropylene powder to the acid scavenger is (10000 to 100000):

1. The main antioxidant is one or a combination of several selected from pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid], 1,3,5-tris(3,5-di-tert-butyl-4-hydroxybenzyl)-S-triazine-2,4,6-(1H,3H,5H)trione, β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid stearyl, 1,3,5-trimethyl-2,4,6-tris(3,5-di-tert-butyl-4-hydroxybenzyl)benzene, and 1,1,3-tris(2-methyl-4-hydroxy-5-tert-butylphenyl)butane, and the mass ratio of the ultra-clean polypropylene powder to the main antioxidant is (1000 to 10000):

1. The manufacturing method according to claim 1, characterized in that the auxiliary antioxidant is one or more selected from dilauryl thiodipropionate, distearyl thiodipropionate, dimyristyl thiodipropionate, tris(nonylphenyl) phosphite, bis(octadecyl)pentaerythritol diphosphite, tris(2,4-t-butylphenyl) phosphite, and bis(2,4-di-tert-butylphenyl)pentaerythritol diphosphite, and the mass ratio of the ultra-clean polypropylene powder to the auxiliary antioxidant is (100 to 10000):

1.

12. A step of polymerizing propylene as a raw material to obtain a crude polypropylene product, A method comprising the step of purifying the obtained crude polypropylene product to obtain polypropylene resin, The step of polymerizing using propylene as a raw material includes the following steps: The propylene prepolymerization step includes polymerizing a predetermined amount of propylene in the presence of a main catalyst and a co-catalyst to form a thin polypropylene layer on the surface of catalyst particles and to obtain a prepolymer slurry, wherein the mass ratio of propylene to the main catalyst in the prepolymerization step is 2.5 to 10 kg / kg, and the mass ratio of the co-catalyst to the main catalyst in the prepolymerization step is 0.18 to 0.5 kg / kg; the propylene prepolymerization step includes introducing propylene at a rate of 10 to 45 kg / h in the presence of the main catalyst and co-catalyst, polymerizing at -5°C to 10°C for 0.5 to 3 hours, and then introducing propylene at a rate of 15 to 55 kg / h until all the remaining propylene is added to the prepolymerization reactor, polymerizing at 12°C to 35°C; Polymerization step: This step involves carrying out a polymerization reaction using propylene as a raw material in the presence of the prepolymer slurry, a co-catalyst, an external electron donor, and hydrogen gas to obtain a crude polypropylene product. The purification method comprises adding crude polypropylene to a composite solvent, thoroughly contacting the crude polypropylene with the composite solvent at 30 to 120°C to form a polypropylene slurry, separating the polypropylene from the composite solvent to obtain polypropylene powder, and drying the polypropylene powder to obtain a polypropylene resin.

13. The production method according to claim 12, wherein the composite solvent is a mixed solvent selected from at least one alkyl alcohol having 1 to 10 carbon atoms and at least one alkane having 5 to 20 carbon atoms that is liquid at room temperature.

14. The manufacturing method according to claim 12, wherein the aforementioned sufficient contact includes contacting the crude polypropylene product with the composite solvent for 0.1 to 5 hours under stirring conditions.

15. The manufacturing method according to claim 12, wherein the mass concentration of polypropylene in the polypropylene slurry is 10 to 40%.

16. The manufacturing method according to claim 12, wherein the purification includes separating polypropylene from a composite solvent by centrifugation to obtain polypropylene powder, and then drying the polypropylene powder at 95 to 120°C to obtain the polypropylene resin.

17. The method according to claim 12, further comprising the step of mixing the obtained polypropylene resin with an antioxidant composite additive and then extruding and granulating it, wherein the mass percentage content of the antioxidant composite additive is 0.2% to 1%, with the mass of the obtained polypropylene resin being 100%.

18. The aforementioned antioxidant complex additive is a combination selected from an acid scavenger, a main antioxidant, and an auxiliary antioxidant, the acid scavenger being a combination of one or more selected from metal stearates and hydrotalcite, the main antioxidant being pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid], 1,3,5-tris(3,5-di-tert-butyl-4-hydroxybenzyl)-S-triazine-2,4,6-(1H,3H,5H)trione, β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid stearyl, 1,3,5-trimethyl-2,4,6-tris(3,5-di-tert-butyl-4-hydroxybenzyl)benzene, and 1,1,3-tris(2-methyl The manufacturing method according to claim 17, wherein the antioxidant is one or a combination of several selected from (2,4-hydroxy-5-tert-butylphenyl)butane, and the auxiliary antioxidant is one or a combination of several selected from dilauryl thiodipropionate, distearyl thiodipropionate, dimyristyl thiodipropionate, tris(nonylphenyl) phosphite, bis(octadecyl)pentaerythritol diphosphite, tris(2,4-t-butylphenyl) phosphite and bis(2,4-di-tert-butylphenyl)pentaerythritol diphosphite, and with the total mass of the antioxidant complex auxiliary being 100%, the mass percentage content of the acid scavenger, main antioxidant and auxiliary antioxidant is 0.1 to 1%, 65 to 90%, and 9.4 to 34.4%, respectively.

19. The production method according to claim 12, wherein the propylene prepolymerization step includes adding a main catalyst to a linear or branched alkane having 4 to 10 carbon atoms, the mass concentration of the main catalyst in the alkane solution being 0.1 to 3%, and further adding propylene and a co-catalyst to carry out the polymerization reaction.

20. The manufacturing method according to claim 12, wherein the mass ratio of the main catalyst to the propylene added in the polymerization step is 0.03 to 0.05 kg / t, the mass ratio of the co-catalyst added in the polymerization step to the propylene added in the polymerization step is 0.1 to 0.15 kg / t, and the mass ratio of the external electron donor to the co-catalyst added in the polymerization step is 0 to 0.1 kg / kg.

21. The polymerization step includes the following steps: Liquid-phase bulk polymerization step: This step includes carrying out liquid-phase bulk polymerization using propylene as a raw material in the presence of the prepolymer slurry, co-catalyst, external electron donor, and hydrogen gas at a temperature of 60°C to 75°C and a pressure of 2.5 to 3.5 MPa; The gas-phase polymerization step includes carrying out gas-phase polymerization of the slurry obtained by liquid-phase bulk polymerization at a temperature of 75°C to 85°C and a pressure of 1.5 to 2.0 MPa to obtain a crude polypropylene product. The manufacturing method according to claim 12.

22. The manufacturing method according to claim 21, wherein the liquid-phase bulk polymerization step includes adding propylene, a prepolymer slurry, a co-catalyst, an external electron donor, and hydrogen gas to a first reaction vessel, carrying out a polymerization reaction at a temperature of 60°C to 75°C and a pressure of 2.5 to 3.5 MPa, the flow rate of the reaction slurry at the outlet of the first reaction vessel being 4.0 to 4.5 g / 10 min, and the hydrogen gas concentration in the first reaction vessel being 1000 to 3000 ppm; and thereafter adding the reaction slurry to a second reaction vessel, introducing hydrogen gas, and carrying out a polymerization reaction at a temperature of 60°C to 75°C and a pressure of 2.5 to 3.5 MPa, the flow rate of the reaction slurry at the outlet of the second reaction vessel being 3.5 to 4.5 g / 10 min, and the hydrogen gas concentration in the second reaction vessel being 1000 to 2000 ppm.

23. The manufacturing method according to claim 12, wherein the main catalyst is a Zn-based catalyst, the co-catalyst is an alkylaluminum compound, and the external electron donor is one or more selected from cyclohexyldimethoxymethylsilane, p-dicyclopentyldimethoxysilane, diisopropyldimethoxysilane, and diisobutyldimethoxysilane.

24. The aforementioned Zn-based catalyst is MgCl 2 Using TiCl as a support, 4 The production method according to claim 23, wherein the catalyst is a combination of one or more catalysts, with a catalyst having an active center and one selected from alkyl-substituted 1,3-diethers, aryl-substituted 1,3-diethers, succinic acid esters, and malonic acid esters as an internal electron donor.

25. The method for producing the alkylaluminum compound according to claim 23, wherein the alkylaluminum compound is one or more combinations selected from trialkylaluminum, alkylaluminoxane, a combination of trialkylaluminum and alkylaluminum halide, or a combination of trialkylaluminum and alkylaluminum hydride.

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