Ultra-clean polypropylene resin and its manufacturing method

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, specifically, the present invention relates to an ultra-clean polypropylene resin and a method for producing the same, more particularly, the present invention relates to an ultra-clean polypropylene resin and a method for producing the same. [Background technology]

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

[0003] Polypropylene is used to manufacture the insulating housings of home appliances and the liners of washing machines, and is generally used as an insulating material for electric wires and cables and other electrical equipment. When manufacturing a barrier film, it can be manufactured using a conventional film-forming process, and the process is simple and the manufacturing cost is low.

[0004] China Patent 201310519301.0 discloses a method for producing materials for homopolypropylene barrier film of lithium-ion batteries. In the present invention, a propylene polymerization catalyst with high activity and suitable hydrogen sensitivity is used, the propylene polymerization activator is triethylaluminum, the amount of which is controlled to be less than 7.0L / h, and the external electron donor is a mixture of dicyclopentyldimethoxysilane and tetraethoxysilane in a molar ratio of 1:1 to 1:8, so that the product has an isotacticity of more than 98%, a melt flow rate of 2.6-3.0g / 10min, an ash content of 50-100ppm, and an ash content index that cannot meet the requirements of high-end electrical application fields.

[0005] Chinese Patent 201080045745.X discloses a catalyst component for olefin polymerization using diol ester type and diether type internal electron donor, a method for preparing said catalyst component, a catalyst containing said catalyst component, and an olefin polymerization method using said catalyst, which are used to prepare low ash polypropylene products. Although the ash content of the product produced by this technology is as low as 30 ppm, it still cannot meet the requirements of high-grade dry power electronic capacitors. Summary of the Invention

[0006] In order to address the problem of high ash content in the products produced by direct polymerization using only a highly active catalyst in the above-mentioned prior art, the present invention aims to provide a method for producing an ultra-clean polypropylene resin.

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

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

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

[0010] In order to achieve the above object, the present invention provides, in one aspect, a method for producing an ultra-clean polypropylene resin, which includes propylene prepolymerization, liquid phase bulk polymerization, gas phase polymerization, polypropylene drying, purification, and extrusion granulation.

[0011] Propylene prepolymerization: A catalyst slurry containing a main catalyst, a cocatalyst and a solvent is prepared in a prepolymerization reactor, and then propylene is introduced to carry out a prepolymerization reaction to obtain a prepolymer slurry.

[0012] Liquid phase bulk polymerization: Propylene is used as a raw material, and 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 polypropylene crude product slurry, and the external electron donor is 9,9-di(methoxymethyl)fluorene.

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

[0014] Polypropylene Drying: The outlet material from the gas-phase fluidized bed reactor is first subjected to gas-solid separation, and the solid phase component is placed in a dryer and dried to obtain polypropylene powder.

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

[0016] Extrusion Granulation: The purified ultra-clean polypropylene powder is mixed with an antioxidant complex auxiliary, and then extrusion granulation is performed to obtain the ultra-clean polypropylene resin.

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

[0018] 1. Propylene prepolymerization: A catalyst slurry containing a main catalyst, a cocatalyst and a solvent is prepared in a prepolymerization reactor, and then propylene is introduced to carry out a prepolymerization reaction to obtain a prepolymer slurry.

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

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

[0021] According to some specific embodiments of the present invention, the prepolymerization reaction preferably includes 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 the prepolymerization time is until all 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 an alkane having 4 to 10 carbon atoms. More preferably, the alkane having 4 to 10 carbon atoms is one or a combination of two or more selected from butane, pentane, hexane, heptane, octane, nonane, and decane, and most preferably hexane. The main catalyst of the present invention is described in Chinese Patent 201080045745.X, and can be incorporated into the present invention or can be commercially available. That is, the main catalyst of the present invention only needs to meet the activity requirement, and the activity of the main catalyst is at least 100,000 times, and the specific calculation method of catalytic activity is the mass ratio of the polymer obtained by propylene polymerization with the catalyst per unit time to the catalyst.

[0023] According to some specific embodiments of the present invention, the main catalyst is preferably a ZN-based catalyst comprising a MgCl2 support, a TiCl4 active center and an internal electron donor, and the internal electron donor is one or more combinations 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, the aryl group of the aryl-substituted 1,3-diethers is preferably a monocyclic or polycyclic C 4-16 More specifically, the aryl group of the aryl-substituted 1,3-diethers is one selected from cyclopentadienyl, indenyl, fluorenyl and derivatives thereof.

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

[0026] However, R1, R2, R3, R4, R5, and R6 may be the same or different, and each independently represents C 1-10 is a straight or branched chain 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 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 are the same or different, and each independently represents C 1-10 More preferably, R7, R8, R9 and R 10 are each 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 a combination of one or more selected from trialkylaluminum, alkylaluminoxane, a combination of trialkylaluminum and alkylaluminum halide, or a combination of trialkylaluminum and alkylaluminum hydride, and most preferably triethylaluminum.

[0031] 2. Liquid phase bulk polymerization: Propylene is used as raw material, and polymerization reaction is carried out in the presence of the prepolymer slurry, cocatalyst, external electron donor and hydrogen gas to obtain polypropylene crude product, and the external electron donor is 9,9-di(methoxymethyl)fluorene.

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

[0033] Propylene, a prepolymer slurry, a cocatalyst, an external electron donor and hydrogen gas are added to a first reaction vessel, 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, the flow rate of the reaction slurry (obtained polypropylene powder melt) 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, and 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 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 melt) 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 0.03-0.05 kg / t, the mass ratio of the co-catalyst to propylene is 0.015-0.0225 kg / t, and the mass ratio of the external electron donor to the co-catalyst is 0-0.015 kg / kg, not including 0.

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

[0036] 3. Gas phase polymerization: The polypropylene crude product slurry obtained by liquid phase bulk polymerization is introduced into a gas phase fluidized bed reactor to carry out the polymerization reaction.

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

[0038] 4. Polypropylene drying: The outlet material from the gas-phase fluidized bed reactor is first subjected to gas-solid separation, and the solid phase component (polypropylene powder) (the separated gas phase portion enters the recovery system for recovery and utilization) is then put into a dryer to dry it and obtain polypropylene powder.

[0039] According to some specific embodiments of the present invention, the solid phase component is preferably dried in a dryer by convection of an inert gas, preferably nitrogen gas, at a drying temperature of 100 to 110°C.

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

[0041] 5. Purification: The dried polypropylene powder is made into a slurry with a composite solvent, and then stirred and purified. The slurry is then separated into solid and liquid to obtain wet polypropylene powder, which is then dried to obtain ultra-clean polypropylene powder.

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

[0043] According to some specific embodiments of the present invention, the ratio of the solvent in the wet polypropylene powder is preferably 15 to 35% (the total mass of the polypropylene powder being taken as 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 the polypropylene powder in the prepared slurry is 10 to 40%.

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

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

[0047] According to some specific embodiments of the present invention, the composite solvent preferably comprises a hydrocarbon-based material and an alkyl alcohol, and the hydrocarbon-based material is preferably a C5-C 20 The hydrocarbon-based substance is preferably a normal alkane or an 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-based substance to the alkyl alcohol is preferably (2 to 6):1.

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

[0049] 6. Extrusion granulation: The purified ultra-clean polypropylene powder is mixed with the antioxidant compound auxiliary, and then extrusion granulation is carried out to obtain the ultra-clean polypropylene resin.

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

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

[0052] Preferably, the acid scavenger is one or a combination of two or more selected from metal stearates and hydrotalcites, and is preferably zinc stearate and calcium stearate, and the mass ratio of the ultra-clean polypropylene powder to the acid scavenger is (10,000 to 100,000):1.

[0053] Preferably, the primary 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)stearyl propionate, 1,3,5-trimethyl-2,4,6-tris(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, and a combination of one or more selected from 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 are 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 a combination of 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 produced by the above production method.

[0058] In the manufacturing method of the present invention, first, a highly active polypropylene catalyst is subjected to a stepwise pre-polymerization treatment, then the prepolymer slurry is injected into two tank-type reactors connected in series to carry out liquid phase bulk polymerization, and then injected into a fluidized bed reactor to carry out 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.

[0059] Further, the present invention relates to a process for producing a polypropylene crude product by polymerizing propylene as a raw material; and a step of purifying the resulting polypropylene crude product to obtain the polypropylene resin, The purification step includes adding a crude polypropylene product to a composite solvent, sufficiently contacting the crude polypropylene product with the composite solvent at 30 to 120°C to form a polypropylene slurry, separating the polypropylene and the composite solvent to obtain a polypropylene powder, and drying the polypropylene powder to obtain the polypropylene resin (ultra-clean polypropylene powder).

[0060] In the polypropylene powder obtained by separating the polypropylene and the composite solvent, the ratio of the solvent is 15 to 35% (the total mass of the polypropylene powder is taken as 100%).

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

[0062] According to some specific embodiments of the present invention, the composite solvent is a mixed solvent of at least one selected from alkyl alcohols having 1 to 10 carbon atoms and at least one selected from alkanes having 5 to 20 carbon atoms that are 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 a combination of a plurality of alcohols selected from methanol, ethanol, propanol, and butanol.

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

[0065] According to some specific embodiments of the present invention, the mass ratio of the alkyl alcohol having 1 to 10 carbon atoms to the 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 the alkyl alcohol having 1 to 10 carbon atoms to the 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 polypropylene crude product to a composite solvent, and thoroughly contacting the polypropylene crude product with the composite solvent at 50-100°C to form a polypropylene slurry.

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

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

[0070] According to some specific embodiments of the present invention, the sufficient contacting includes contacting the polypropylene crude 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 the polypropylene and the composite solvent by centrifugation to obtain polypropylene powder, and then drying the polypropylene powder at 95 to 120°C to obtain the polypropylene resin.

[0074] According to some specific embodiments of the present invention, the purification includes separating the polypropylene and the 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 h.

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

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

[0078] According to some specific embodiments of the present invention, the method further includes a step of extrusion granulation after mixing the obtained polypropylene resin and the antioxidant complex co-agent.

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

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

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

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

[0083] According to some specific embodiments of the present invention, the primary antioxidant is one or more combinations 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)stearyl propionate, 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 primary antioxidant is one or more combinations 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 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.

[0086] According to some specific embodiments of the present invention, the supplemental 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 complex auxiliary is 0.2% to 1%, based on 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 feedstock comprises the following steps:

[0089] Propylene prepolymerization step: a predetermined amount of propylene is polymerized in the presence of a main catalyst and a cocatalyst to form a thin polypropylene layer on the surface of catalyst particles, wherein the mass ratio of propylene to the main catalyst in the prepolymerization step is 2.5-10 kg / kg, and the mass ratio of the cocatalyst to the main catalyst in the prepolymerization step is 0.18-0.5 kg / kg, and a prepolymer slurry is obtained.

[0090] Polymerization step: 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.

[0091] According to some specific embodiments of the present invention, the propylene prepolymerization step includes: in the presence of a main catalyst and a cocatalyst, introducing propylene at 10-45 kg / h, polymerizing at -5°C-15°C for 0.5-3 h, and then introducing propylene at 15-55 kg / h, polymerizing at 5°C-35°C until all 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 10 to 45 kg / h in the presence of a main catalyst and a cocatalyst, polymerizing at -5°C to 15°C for 0.5 to 3 hours, and then introducing propylene at 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, the mass concentration of the main catalyst in the solution of the alkane is 0.1 to 3%, and further adding propylene and a co-catalyst to carry out a polymerization reaction.

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

[0095] According to some specific embodiments of the present invention, after the prepolymer slurry is obtained in the prepolymerization step, a predetermined amount of an alkane having 4 to 10 carbon atoms is further added to dilute the prepolymer slurry, 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 alkane having 4 to 10 carbon atoms is one or a combination of a plurality of alkanes 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 0.03-0.05 kg / t, the mass ratio of the co-catalyst added in the polymerization step to the propylene added in the polymerization step is 0.1-0.15 kg / t, and the mass ratio of the external electron donor to the co-catalyst added in the polymerization step is 0-0.1 kg / kg.

[0098] Here, it can be understood that when the mass ratio of the external electron donor to the cocatalyst is 0, this indicates that it is not necessary to add an 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 3.2-3.6 kg / kg.

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

[0101] Liquid phase bulk polymerization step: Using propylene as a raw material, liquid phase bulk polymerization is carried out in the presence of the prepolymer slurry, a cocatalyst, an 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] Gas phase polymerization step: The slurry obtained by the liquid phase bulk polymerization is subjected to gas phase 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 feedstock in the liquid phase bulk polymerization step is purified propylene.

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

[0105] According to some specific embodiments of the present invention, the liquid phase bulk polymerization step includes: adding propylene, prepolymer slurry, cocatalyst, external electron donor and hydrogen gas to a first reactor, and carrying out a polymerization reaction at a temperature of 60°C to 75°C and a pressure of 2.5 to 3.5MPa, the flow rate of the reaction slurry (obtained polypropylene powder melt) at the outlet of the first reactor is 4.0 to 4.5g / 10min, and the hydrogen gas concentration in the first reactor is 1000 to 3000ppm; then adding the reaction slurry to a second reactor, 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 3.5MPa, the flow rate of the reaction slurry (obtained polypropylene powder melt) at the outlet of the second reactor is 3.5 to 4.5g / 10min, and the hydrogen gas concentration in the second reactor is 1000 to 2000ppm.

[0106] According to some specific embodiments of the present invention, the liquid phase bulk polymerization step is as follows: propylene, prepolymer slurry, cocatalyst, external electron donor and hydrogen gas are added to a first reactor, and 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 (obtained polypropylene powder melt) at the outlet of the first reactor is 4.5 g / 10 min, and the hydrogen gas concentration in the first reactor is 2890 ppm; then, the reaction slurry is added to a second reactor, hydrogen gas is introduced, and 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 (obtained polypropylene powder melt) at the outlet of the second reactor is 4.5 g / 10 min, and the hydrogen gas concentration in the second reactor is 1300 ppm.

[0107] According to some specific embodiments of the present invention, the liquid phase bulk polymerization step is carried out by adding propylene, prepolymer slurry, cocatalyst, external electron donor and hydrogen gas to a first reactor, and carrying out a polymerization reaction at a temperature of 70°C and a pressure of 3.0 MPa (liquid level 49%), the flow rate of the reaction slurry (obtained polypropylene powder melt) at the outlet of the first reactor 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 reactor was 2890 ppm, and then the reaction slurry was added to the second reactor and hydrogen gas was introduced, and the supply amount of hydrogen gas was 2.0 Nm 2 / h, the polymerization reaction was 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 (obtained polypropylene powder melt) at the outlet of the second reaction vessel was 4.5 g / 10 min, and the hydrogen gas concentration in the second reaction vessel was 1300 ppm.

[0108] According to some specific embodiments of the present invention, the first and second reactor vessels are connected in series (resulting in a perfectly mixed flow multi-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 through gas phase polymerization, and the flow rate of the polypropylene powder melt at the outlet of the gas phase polymerization reactor 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 gas phase polymerization of the slurry obtained from the liquid phase bulk polymerization at a temperature of 80° C. and a pressure of 1.8 MPa to obtain a polypropylene crude product.

[0112] According to some specific embodiments of the present invention, the ash content of the polypropylene crude 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 polypropylene crude 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 polypropylene crude product obtained by gas phase polymerization is 10-30 ppm.

[0115] According to some specific embodiments of the present invention, the step of polymerizing propylene as a raw material further includes a 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, drying in the step of polymerizing propylene as a raw material is performed by convection of an inert gas in a dryer.

[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 a step of obtaining a solid content by gas-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 comprises performing 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 catalyst consumed.

[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 combinations selected from cyclohexyldimethoxymethylsilane, p-dicyclopentyldimethoxysilane, diisopropyldimethoxysilane and diisobutyldimethoxysilane.

[0125] According to some specific embodiments of the present invention, the ZN-based catalyst is one or more of the catalysts having 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-diethers is a monocyclic or polycyclic C 4~16 It is selected from aryl groups.

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

[0128] According to some specific embodiments of the present invention, the structure of the alkyl-substituted 1,3-diethers is represented by the following formula (I), and the structure of the 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 may be the same or different, and each independently represents C 1-10 is a straight or branched chain 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 each 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 are the same or different, and each independently represents C 1-10 is a straight or branched chain alkyl group.

[0133] According to some specific embodiments of the present invention, R7, R8, R9 and R 10 are the same or different and each 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 Beijing Oda 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 1-10 is a straight or branched chain 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, butyl, pentyl, heptyl, octyl, nonyl and decyl groups of the present invention may be either the straight chain structures of the above groups or various branched chain 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 comprises the following steps:

[0141] (1) Propylene prepolymerization: The main catalyst is first mixed with an alkane having 4 to 10 carbon atoms to dilute it, and the mass concentration of the diluted slurry is 0.1 to 3%. Then, the cocatalyst 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. The first stage 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 h. The second stage prepolymerization temperature is 5°C to 35°C, the amount of propylene added is 15 to 55 kg / h, and the prepolymerization is continued until all the remaining propylene is added to the prepolymerization reactor (prepolymerization tank).

[0142] (2) Liquid-phase bulk polymerization: Propylene, a prepolymer slurry, a cocatalyst, an external electron donor and an appropriate amount of hydrogen gas are added to a first reactor (tank-type polymerization reactor) to carry out liquid-phase bulk polymerization. The polymerization temperature is 60-75°C, the polymerization pressure is 2.5-3.5MPa, the melt flow rate of the polypropylene powder at the outlet of the first reactor is 4.0-4.5g / 10min, the mass ratio of the main catalyst to propylene is 0.03-0.05kg / t, the mass ratio of the cocatalyst to propylene is 0.1-0.15kg / t, and the external electron donor is 0.02-0.05kg / t. The mass ratio of the donor to the cocatalyst 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 introduced into a second reactor (tank-type polymerization reactor) to carry out a 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 and the hydrogen gas concentration is 1000-2000 ppm.

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

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

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

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

[0147] As described above, the propylene polymerization of the present invention uses two tank reactors connected in series to carry out liquid phase bulk polymerization, and then uses one fluidized bed reactor to carry out gas phase polymerization. Then, the polypropylene base is washed with a blended solvent made of hydrocarbon and alcohol solvents to remove catalyst residues and amorphous polypropylene, and an antioxidant complex auxiliary is used to avoid secondary pollution of polypropylene products caused by impurities, thereby realizing the industrialized production of ultra-clean polypropylene.

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

[0149] According to some specific embodiments of the present invention, the ash content of the polypropylene resin obtained through 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 polypropylene resin obtained through extrusion granulation has a melt flow rate of 3.0 to 3.1 g / 10 min.

[0153] As described above, 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, the catalytic activity can be improved by effectively activating the catalytic active sites inside the highly active catalyst particles through two-stage prepolymerization. Compared with the prior art, the polypropylene produced by the present invention has a lower ash content, and the product has good electrical properties and can meet the requirements of high-end capacitors.

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

[0156] (3) The bulk polymerization and deep purification process used in the present invention uses an organic composite solvent to remove metal impurities and polypropylene oligomers, and the resin products produced have lower ash content and higher isotacticity, which can meet the requirements of high-end capacitors. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

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

[0158] From raw materials or equipment: Propylene is provided by Lanzhou Petrochemical Industry Co., Ltd., the catalyst is provided by Beijing Oda Catalyst Factory, triethylaluminum is provided by Yingkou Xiangyang Catalyst Factory, cyclohexylmethyldimethoxysilane is provided by Shandong Luxiang Chemical Industry Technology Co., Ltd., and hydrogen gas is provided by Lanzhou Petrochemical Industry Co., Ltd.

[0159] Evaluation analysis method: 1. Melt index of polymer: Measured according to GB / T 3682-2000. 2. Polymer isotacticity: Measured according to GB / T 2412-2008. 3. Polymer ash content: measured according to GB / T 9345.1-2008.

[0160] Specific examples:

[0161] Example 1-1 Preparation of propylene prepolymer slurry Add 500kg of hexane and 7kg of triethylaluminum to the catalyst preparation tank, in which the mass concentration of triethylaluminum solution is 15%, add 25kg of titanium metal catalyst (Beijing Oda HA-R catalyst) supported by magnesium chloride, stir to form a uniform suspension, use frozen salt water to lower the temperature of the preparation tank to below 5℃, add 1500kg of new hexane to adjust the concentration of the catalyst slurry, and stir until 80r / min. In the first stage of prepolymerization, open the gas phase propylene automatic supply valve, adjust the propylene supply rate to 10kg / h, stir until 40r / min, lower the temperature of the preparation tank to below -5℃, and prepolymerize for 1h. In the second stage of prepolymerization, adjust the propylene feed rate to 15kg / h, start stirring to 40r / min, reduce the temperature of the preparation tank to 5°C, prepolymerize until 100kg of propylene is all consumed, obtain propylene prepolymer slurry, and transfer the prepolymer slurry to a storage tank for use.

[0162] Example 1-2 Preparation of propylene prepolymer slurry Add 400kg of hexane and 7kg of triethylaluminum to the catalyst preparation tank, in which the mass concentration of triethylaluminum solution is 15%, add 30kg of titanium metal catalyst (Beijing Oda HA-R catalyst) supported by magnesium chloride, stir to form a uniform suspension, use frozen salt water to lower the temperature of the preparation tank below 5℃, add 1400kg of new hexane to adjust the concentration of the catalyst slurry, and stir until 80r / min. In the first stage of prepolymerization, open the gas phase propylene automatic supply valve, adjust the propylene supply rate to 45kg / h, stir until 40r / min, lower the temperature of the preparation tank to 15℃, and prepolymerize for 1h. In the second stage of prepolymerization, adjust the propylene feed rate to 55kg / h, start stirring to 40r / min, reduce the temperature of the preparation tank to 35°C, prepolymerize until 100kg of propylene is all consumed, obtain propylene prepolymer slurry, and transfer the prepolymer slurry to a storage tank for use.

[0163] Examples 1-3 Preparation of propylene prepolymer slurry Add 500kg of hexane and 7kg of triethylaluminum to the catalyst preparation tank, in which the mass concentration of triethylaluminum solution is 15%, add 32.5kg of titanium metal catalyst (Beijing Oda HA-R catalyst) supported by magnesium chloride, stir to form a uniform suspension, use frozen salt water to lower the temperature of the preparation tank below 5℃, add 700kg of new hexane to adjust the concentration of the catalyst slurry, and stir until 80r / min. In the first stage of prepolymerization, open the gas phase propylene automatic supply valve, adjust the propylene supply rate to 25kg / h, stir until 40r / min, lower the temperature of the preparation tank to 5℃, and prepolymerize for 1h. In the second stage of prepolymerization, adjust the propylene feed rate to 30kg / h, start stirring to 40r / min, lower the temperature of the preparation tank to 12°C, prepolymerize until 100kg of propylene is all consumed, obtain propylene prepolymer slurry, and transfer the prepolymer slurry to a storage tank for use.

[0164] Examples 1-4 Preparation of propylene prepolymer slurry Add 550kg of hexane and 7kg of triethylaluminum to the catalyst preparation tank, in which the mass concentration of triethylaluminum solution is 15%, add 34.5kg of titanium metal catalyst (Beijing Oda HA-R catalyst) supported by magnesium chloride, stir to form a uniform suspension, use frozen salt water to lower the temperature of the preparation tank below 5℃, add 1400kg of new hexane to adjust the concentration of the catalyst slurry, and stir until 80r / min. In the first stage of prepolymerization, open the gas phase propylene automatic supply valve, adjust the propylene supply rate to 30kg / h, stir until 40r / min, lower the temperature of the preparation tank to 8℃, and prepolymerize for 1h. In the second stage of prepolymerization, adjust the propylene feed rate to 30kg / h, start stirring to 40r / min, reduce the temperature of the preparation tank to 15°C, prepolymerize until 100kg of propylene is all consumed, obtain propylene prepolymer slurry, and transfer the prepolymer slurry to a storage tank for use.

[0165] Examples 1-5 Preparation of propylene prepolymer slurry Add 500kg of hexane and 7kg of triethylaluminum to the catalyst preparation tank, in which the mass concentration of triethylaluminum solution is 15%, add 35.5kg of titanium metal catalyst (Beijing Oda HA-R catalyst) supported by magnesium chloride, stir to form a uniform suspension, use frozen salt water to lower the temperature of the preparation tank below 5℃, add 1400kg of new hexane to adjust the concentration of the catalyst slurry, and stir until 80r / min. In the first stage of prepolymerization, open the gas phase propylene automatic supply valve, adjust the propylene supply rate to 30kg / h, stir until 40r / min, lower the temperature of the preparation tank to 10℃, and prepolymerize for 1h. In the second stage of prepolymerization, adjust the propylene feed rate to 40kg / h, start stirring to 40r / min, lower the temperature of the preparation tank to 20°C, prepolymerize until 100kg of propylene is all consumed, obtain propylene prepolymer slurry, and transfer the prepolymer slurry to a storage tank for use.

[0166] Examples 1-6 Preparation of propylene prepolymer slurry Add 600kg of hexane and 7kg of triethylaluminum to the catalyst preparation tank, in which the mass concentration of triethylaluminum solution is 15%, add 34.5kg of titanium metal catalyst (Beijing Oda HA-R catalyst) supported by magnesium chloride, stir to form a uniform suspension, use frozen salt water to lower the temperature of the preparation tank below 5℃, add 1400kg of new hexane to adjust the concentration of the catalyst slurry, and stir until 80r / min. In the first stage of prepolymerization, open the gas phase propylene automatic supply valve, adjust the propylene supply rate to 35kg / h, stir until 40r / min, lower the temperature of the preparation tank to 12℃, and prepolymerize for 1h. In the second stage of prepolymerization, adjust the propylene feed rate to 40kg / h, start stirring to 40r / min, reduce the temperature of the preparation tank to 18°C, prepolymerize until 100kg of propylene is all consumed, obtain propylene prepolymer slurry, and transfer the prepolymer slurry to a storage tank for use.

[0167] Examples 1-7 Preparation of propylene prepolymer slurry Add 500kg of hexane and 7.2kg of triethylaluminum to the catalyst preparation tank, in which the mass concentration of triethylaluminum solution is 15%, add 36kg of titanium metal catalyst (Beijing Oda HA-R catalyst) supported by magnesium chloride, stir to form a uniform suspension, use frozen salt water to lower the temperature of the preparation tank below 5℃, add 1400kg of new hexane to adjust the concentration of the catalyst slurry, and stir until 80r / min. In the first stage of prepolymerization, open the gas phase propylene automatic supply valve, adjust the propylene supply rate to 25kg / h, stir until 40r / min, lower the temperature of the preparation tank to 14℃, and prepolymerize for 1h. In the second stage of prepolymerization, adjust the propylene feed rate to 30kg / h, start stirring to 40r / min, lower the temperature of the preparation tank below 20°C, prepolymerize until 100kg of propylene is all consumed, obtain propylene prepolymer slurry, and transfer the prepolymer slurry to storage tank for use.

[0168] Examples 1-8 Preparation of propylene prepolymer slurry Add 550kg of hexane and 5kg of triethylaluminum to the catalyst preparation tank, in which the mass concentration of triethylaluminum solution is 15%, add 10kg of titanium metal catalyst (Beijing Oda HA-R catalyst) supported by magnesium chloride, stir to form a uniform suspension, use frozen salt water to lower the temperature of the preparation tank below 5℃, add 1400kg of new hexane to adjust the concentration of the catalyst slurry, and stir to 80r / min. In the first stage of prepolymerization, open the gas phase propylene automatic supply valve, adjust the propylene supply rate to 25kg / h, stir to 40r / min, lower the temperature of the preparation tank to 9℃, and prepolymerize for 1h. In the second stage of prepolymerization, adjust the propylene feed rate to 30kg / h, start stirring to 40r / min, lower the temperature of the preparation tank to 16°C, prepolymerize until 100kg of propylene is all consumed, obtain propylene prepolymer slurry, and transfer the prepolymer slurry to a storage tank for use.

[0169] The catalyst slurries produced in the above Examples 1-1 to 1-8 are used in the production of polypropylene in Comparative Examples 1 to 8, respectively, and a more suitable catalyst slurry is selected.

[0170] Example 2 Polypropylene manufacturing method

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

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

[0173] Gas Phase Polymerization Reaction The slurry at the outlet of the second tank reactor is introduced into a gas-phase fluidized bed reactor to carry out polymerization reaction, the polymerization temperature is 80°C, the polymerization pressure is 1.8MPa, and the raw material position is 51%.

[0174] Polypropylene drying The material at the outlet of the gas-phase fluidized bed reactor first enters the cyclone separator to separate the material into gas and solid. The separated solid polypropylene powder enters the dryer and is dried by convection inert gas at a drying temperature of 105°C.

[0175] Polypropylene Refining After the polypropylene powder is dried with inert gas, it is transported to a polymer high-purification tank, and a certain amount of composite solvent (a composite solvent of hexane and ethanol, mass ratio 4:1) is added to form a polymer powder slurry with a slurry concentration of 10%, and the polymer is highly purified under a certain process condition (stirring speed 50 rpm, slurry supply rate 20 t / h), the purification temperature is 30 ° C, and the purification time is 0.1 h. The highly purified polymer slurry is centrifuged to obtain polymer wet powder, and the proportion of the solvent in the wet powder is 25%, and it is further subjected to a multi-stage drying (drying temperature 105 ° C) process to remove volatile organic compounds. Then it is transported to an extrusion granulation unit to obtain the capacitor film ultra-clean polypropylene resin.

[0176] Extrusion Granulation The antioxidant complex auxiliary with low ash content and long-term effect (antioxidant 1010 is 2000mg / kg, 168 is 1000mg / kg, calcium stearate is 80mg / kg) and dried polypropylene powder are simultaneously added to a twin-screw extruder and extrusion granulated (granulation temperature is 225℃, screw speed is 120rpm) to obtain ultra-clean polypropylene resin for capacitor film.

[0177] Example 3 The manufacturing process is the same as in Example 2. The differences are as follows: After the polypropylene powder is dried with inert gas, it is transported to a polymer high-purification tank, and a certain amount of composite solvent (a composite solvent of hexane and ethanol, mass ratio 4:1) is added to form a polymer powder slurry with a slurry concentration of 30%, and the polymer is highly purified under the specified process conditions, the purification temperature is 70 ° C, and the purification time is 3h. The highly purified polymer slurry is centrifuged to obtain polymer wet powder, and the proportion of the solvent in the wet powder is 25%, and it is further subjected to a multi-stage drying (drying temperature 105 ° C) process to remove volatile organic compounds. It is then transported to the extrusion granulation unit to obtain the capacitor film ultra-clean polypropylene resin.

[0178] Example 4 The manufacturing process is the same as in Example 2. The differences are as follows: After the polypropylene powder is dried with inert gas, it is transported to a polymer high-purification tank, and a certain amount of composite solvent (a composite solvent of hexane and ethanol, mass ratio 4:1) is added to form a polymer powder slurry with a slurry concentration of 40%, and the polymer is highly purified under the specified process conditions, the purification temperature is 120°C, and the purification time is 5h. The highly purified polymer slurry is centrifuged to obtain polymer wet powder, and the proportion of the solvent in the wet powder is 25%, and it is further subjected to a multi-stage drying (drying temperature 105°C) process to remove volatile organic compounds. It is then transported to the extrusion granulation unit to obtain the capacitor film ultra-clean polypropylene resin.

[0179] Example 5 The manufacturing process is the same as in Example 2. The differences are as follows: After the polypropylene powder is dried with inert gas, it is transported to a polymer high-purification tank and a certain amount of composite solvent (a composite solvent of hexane and ethanol, mass ratio 4:1) is added to form a polymer powder slurry with a slurry concentration of 35%, and the polymer is highly purified under the specified process conditions, the purification temperature is 60°C, and the purification time is 1h. The highly purified polymer slurry is centrifuged to obtain polymer wet powder, and the proportion of the solvent in the wet powder is 25%, and it is further subjected to a multi-stage drying (drying temperature 105°C) process to remove volatile organic compounds. It is then transported to the extrusion granulation unit to obtain the capacitor film ultra-clean polypropylene resin.

[0180] Example 6 The manufacturing process is the same as in Example 2. The differences are as follows: After the polypropylene powder is dried with inert gas, it is transported to a polymer high-purification tank, and a certain amount of composite solvent (a composite solvent of hexane and ethanol, mass ratio 4:1) is added to form a polymer powder slurry with a slurry concentration of 40%, and the polymer is highly purified under the specified process conditions, the purification temperature is 60°C, and the purification time is 1h. The highly purified polymer slurry is centrifuged to obtain polymer wet powder, and the proportion of the solvent in the wet powder is 25%, and it is further subjected to a multi-stage drying (drying temperature 105°C) process to remove volatile organic compounds. It is then transported to the extrusion granulation unit to obtain the capacitor film ultra-clean polypropylene resin.

[0181] Example 7 The manufacturing process is the same as in Example 2. The differences are as follows: Low ash and long-lasting antioxidant complex auxiliary (antioxidant 1010 is 5000mg / kg, 168 is 1600mg / kg, calcium stearate is 40mg / kg) and dried polypropylene powder are simultaneously added to a twin-screw extruder and extrusion granulated (granulation temperature is 225℃, screw speed is 120rpm) to obtain ultra-clean polypropylene resin for condenser film.

[0182] Example 8 The manufacturing process is the same as in Example 2. The differences are as follows: A low-ash, long-lasting antioxidant complex auxiliary (antioxidant 1010 is 10,000 mg / kg, 168 is 1,200 mg / kg, and calcium stearate is 30 mg / kg) and dried polypropylene powder are simultaneously added to a twin-screw extruder and extrusion granulated (granulation temperature is 225°C, screw rotation speed is 120 rpm) to obtain an ultra-clean polypropylene resin for condenser film. The polypropylene resins produced in Examples 2 to 8 were subjected to performance measurements, and the results are shown in Table 1. [Table 1]

[0183] Example 9 Propylene prepolymerization: Add 500kg of hexane and 7kg of triethylaluminum solution (15% mass concentration in hexane solvent) to catalyst preparation tank, add 25kg of titanium metal catalyst (Beijing Oda HA-R catalyst) supported by magnesium chloride, stir to form a uniform suspension, cool the temperature of the preparation tank to below 5℃ with frozen salt water, add 1500kg of new hexane to adjust the concentration of catalyst slurry, and stir to 80r / min. In the first stage of prepolymerization, open the gas phase propylene automatic supply valve, adjust the propylene supply rate to 10kg / h, stir to 40r / min, cool the temperature of the preparation tank to below -5℃, and prepolymerize for 1h. In the second stage of prepolymerization, adjust the propylene feed rate to 15kg / h, start stirring to 40r / min, reduce the temperature of the preparation tank to 5°C, prepolymerize until 100kg of propylene is all consumed, obtain propylene prepolymer slurry, and transfer the propylene prepolymer slurry to a storage tank for use.

[0184] Liquid phase bulk polymerization: The propylene prepolymer slurry, propylene, cocatalyst, external electron donor and an appropriate amount of hydrogen gas were added to a first-tank reactor to carry out liquid-phase bulk polymerization. The gas-phase propylene was refluxed into the reactor through a tank top cooler. The polymerization temperature was 70°C, the polymerization pressure was 3.0 MPa, the liquid level was 49%, the prepolymer slurry was fed at 14.0 kg / h, the propylene was fed at 5.7 t / h, the triethylaluminum solution was fed at 0.8 kg / h, the 9,9-di(methoxymethyl)fluorene was fed at 0.07 kg / h, and the hydrogen gas was fed at 4.9 Nm 2 / h, and 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 introduced into the second tank reactor to carry out the polymerization reaction. The temperature of the second tank reactor was 64°C, the polymerization pressure was 2.6MPa, the liquid level was 44%, and hydrogen gas was added to the second tank reactor at a supply rate of 2.0Nm 2 / h, hydrogen gas concentration is 1300ppm. The outlet flow rate of the reaction slurry is 4.5t / h.

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

[0187] Polypropylene Drying: The material at the outlet of the gas-phase fluidized bed reactor first enters a cyclone separator to separate the material into gas and solid. The separated solid polypropylene powder enters a dryer and is dried by convection nitrogen gas at a drying temperature of 105°C.

[0188] purification: After the polypropylene powder is dried with inert gas, it is transported to a polymer high-purification tank, and a certain amount of composite solvent (a composite solvent of hexane and ethanol, mass ratio 4:1) is added to form a polymer powder slurry with a slurry concentration of 30%, and the polymer is highly purified under a certain process condition (stirring speed 50 rpm, slurry supply rate 20 t / h), the purification temperature is 60 ° C, and the purification time is 0.5 h. The highly purified polymer slurry is centrifuged to obtain polymer wet powder, and the proportion of the solvent in the wet powder is 25%, and it is further subjected to a multi-stage drying (drying temperature 105 ° C) process to remove volatile organic compounds. Then it is transported to an extrusion granulation unit to obtain the capacitor film ultra-clean polypropylene resin.

[0189] Extrusion Granulation: The antioxidant complex auxiliary with low ash content and long-term effect (antioxidant 1010 is 2000mg / kg, 168 is 1000mg / kg, calcium stearate is 80mg / kg) and dried polypropylene powder are simultaneously added to a twin-screw extruder and extrusion granulated (granulation temperature is 225℃, screw speed is 120rpm) to obtain ultra-clean polypropylene resin for capacitor film.

[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 Oda HA-R catalyst) supported by magnesium chloride is added, and the mixture is stirred to form a uniform suspension. The temperature of the preparation tank is lowered to below 5°C with frozen brine, and 1400 kg of new hexane is added to adjust the concentration of the catalyst slurry, and the mixture is stirred and started to reach 80r / min. In the first stage of prepolymerization, the gas phase propylene automatic supply valve is opened, the propylene supply rate is adjusted to 45kg / h, and the mixture is stirred and started to reach 40r / min, the temperature of the preparation tank is lowered to 15°C, and the mixture is prepolymerized for 1h. In the second stage of prepolymerization, the propylene supply rate is adjusted to 55kg / h, and the mixture is stirred and started to reach 40r / min, the temperature of the preparation tank is lowered to 35°C, and the mixture is prepolymerized until 100 kg of propylene is all consumed, and a propylene prepolymer slurry is obtained, and the above prepolymer slurry is 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 Oda HA-R catalyst) supported by magnesium chloride is added, and the mixture is stirred to form a uniform suspension. The temperature of the preparation tank is lowered to below 5°C with frozen brine, and 700 kg of new hexane is added to adjust the concentration of the catalyst slurry, and the mixture is stirred and started to reach 80r / min. In the first stage of prepolymerization, the gas phase propylene automatic supply valve is opened, the propylene supply rate is adjusted to 25kg / h, and the mixture is stirred and started to reach 40r / min, the temperature of the preparation tank is lowered to 5°C, and the mixture is prepolymerized for 1h. In the second stage of prepolymerization, the propylene supply rate is adjusted to 30kg / h, and the mixture is stirred and started to reach 40r / min, the temperature of the preparation tank is lowered to 12°C, and the mixture is prepolymerized until 100 kg of propylene is all consumed, and a propylene prepolymer slurry is obtained, and the above prepolymer slurry is 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 Oda HA-R catalyst) supported by magnesium chloride is added, and the mixture is stirred to form a uniform suspension. The temperature of the preparation tank is lowered to below 5°C with frozen brine, and 1400 kg of new hexane is added to adjust the concentration of the catalyst slurry, and the mixture is stirred and started to reach 80r / min. In the first stage of prepolymerization, the gas phase propylene automatic supply valve is opened, the propylene supply rate is adjusted to 30kg / h, and the mixture is stirred and started to reach 40r / min, the temperature of the preparation tank is lowered to 8°C, and the mixture is prepolymerized for 1h. In the second stage of prepolymerization, the propylene supply rate is adjusted to 30kg / h, and the mixture is stirred and started to reach 40r / min, the temperature of the preparation tank is lowered to 15°C, and the mixture is prepolymerized until 100 kg of propylene is all consumed, and a propylene prepolymer slurry is obtained, and the above prepolymer slurry is 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 Oda HA-R catalyst) supported by magnesium chloride is added, and the mixture is stirred to form a uniform suspension. The temperature of the preparation tank is lowered to below 5°C with frozen brine, and 1400 kg of new hexane is added to adjust the concentration of the catalyst slurry, and the mixture is stirred and started to reach 80r / min. In the first stage of prepolymerization, the gas phase propylene automatic supply valve is opened, the propylene supply rate is adjusted to 30kg / h, and the mixture is stirred and started to reach 40r / min, the temperature of the preparation tank is lowered to 10°C, and the mixture is prepolymerized for 1h. In the second stage of prepolymerization, the propylene supply rate is adjusted to 40kg / h, and the mixture is stirred and started to reach 40r / min, the temperature of the preparation tank is lowered to 20°C, and the mixture is prepolymerized until 100 kg of propylene is all consumed, and a propylene prepolymer slurry is obtained, and the above prepolymer slurry is 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 Oda HA-R catalyst) supported by magnesium chloride is added, and the mixture is stirred to form a uniform suspension. The temperature of the preparation tank is lowered to below 5°C with frozen brine, and 1400 kg of new hexane is added to adjust the concentration of the catalyst slurry, and the mixture is stirred and started to reach 80r / min. In the first stage of prepolymerization, the gas phase propylene automatic supply valve is opened, the propylene supply rate is adjusted to 35kg / h, and the mixture is stirred and started to reach 40r / min, the temperature of the preparation tank is lowered to 12°C, and the mixture is prepolymerized for 1h. In the second stage of prepolymerization, the propylene supply rate is adjusted to 40kg / h, and the mixture is stirred and started to reach 40r / min, the temperature of the preparation tank is lowered to 18°C, and the mixture is prepolymerized until 100 kg of propylene is all consumed, and a propylene prepolymer slurry is obtained, and the above prepolymer slurry is 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 Oda HA-R catalyst) supported by magnesium chloride is added, and the mixture is stirred to form a uniform suspension. The temperature of the preparation tank is lowered to below 5°C with frozen salt water, and 1400 kg of new hexane is added to adjust the concentration of the catalyst slurry, and the mixture is stirred and started to reach 80r / min. In the first stage of prepolymerization, the gas phase propylene automatic supply valve is opened, the propylene supply rate is adjusted to 25kg / h, and the mixture is stirred and started to reach 40r / min, the temperature of the preparation tank is lowered to 14°C, and the mixture is prepolymerized for 1h. In the second stage of prepolymerization, the propylene supply rate is adjusted to 30kg / h, and the mixture is stirred and started to reach 40r / min, the temperature of the preparation tank is lowered to below 20°C, and the mixture is prepolymerized until 100 kg of propylene is all consumed, and a propylene prepolymer slurry is obtained, and the above prepolymer slurry is 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 Oda HA-R catalyst) supported by magnesium chloride is added, and the mixture is stirred to form a uniform suspension. The temperature of the preparation tank is lowered to below 5°C with frozen brine, and 1400 kg of new hexane is added to adjust the concentration of the catalyst slurry, and the mixture is stirred and started to reach 80r / min. In the first stage of prepolymerization, the gas phase propylene automatic supply valve is opened, the propylene supply rate is adjusted to 25kg / h, and the mixture is stirred and started to reach 40r / min, the temperature of the preparation tank is lowered to 9°C, and the mixture is prepolymerized for 1h. In the second stage of prepolymerization, the propylene supply rate is adjusted to 30kg / h, and the mixture is stirred and started to reach 40r / min, the temperature of the preparation tank is lowered to 16°C, and the mixture is prepolymerized until 100 kg of propylene is all consumed, and a propylene prepolymer slurry is obtained. The above prepolymer slurry is transferred to a storage tank for use.

[0197] The polypropylene resins produced in Examples 9 to 16 were subjected to performance measurements, and the results are shown in Table 2. [Table 2]

[0198] Comparative Example 1 Polypropylene manufacturing method

[0199] Liquid Phase Bulk Polymerization The catalyst slurry, propylene, cocatalyst, external electron donor and an appropriate amount of hydrogen gas were added to a first-tank reactor to carry out liquid-phase bulk polymerization. The gas-phase propylene was refluxed into the reactor through a tank top cooler. The polymerization temperature was 70°C, the polymerization pressure was 3.0 MPa, the liquid level was 49%, the catalyst slurry prepared in Example 1-1 was fed at 15.0 kg / h, the propylene was fed at 5.7 t / h, the triethylaluminum was fed at 0.8 kg / h, the cyclohexylmethyldimethoxysilane was fed at 0.07 kg / h, and the hydrogen gas was fed at 4.9 Nm 2 / h and the hydrogen gas concentration is 1000 ppm.

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

[0201] Gas Phase Polymerization Reaction The slurry at the outlet of the second tank reactor is introduced into a gas-phase fluidized bed reactor to carry out polymerization reaction, the polymerization temperature is 80°C, the polymerization pressure is 1.8MPa, and the raw material position is 51%.

[0202] Polypropylene drying The material at the outlet of the gas-phase fluidized bed reactor first enters a cyclone separator to separate the material into gas and solid. The separated solid polypropylene powder enters a dryer and is dried by convection inert gas at a drying temperature of 105°C.

[0203] Extrusion Granulation The low ash, long-lasting antioxidant compound auxiliary and dried polypropylene powder are simultaneously added to a twin-screw extruder and extrusion granulated to obtain ultra-clean polypropylene resin for capacitor film.

[0204] Comparative Example 2 The manufacturing process was the same as in Comparative Example 1. The difference is that the catalyst slurry prepared in Example 1-2 was used, the supply rate of the catalyst slurry to 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 Nm 2 / h and the hydrogen gas concentration is 3000 ppm.

[0205] Comparative Example 3 The manufacturing process was the same as in Comparative Example 1. The difference is that the catalyst slurry prepared in Example 1-3 was used and the feed rate was 14.5 kg / h.

[0206] Comparative Example 4 The manufacturing process was the same as in Comparative Example 1. The difference is that the catalyst slurry prepared in Example 1-4 was used and the feed rate was 16.2 kg / h.

[0207] Comparative Example 5 The manufacturing process was the same as in Comparative Example 1. The difference is that the catalyst slurry prepared in Examples 1-5 was used and the feed rate was 16.3 kg / h.

[0208] Comparative Example 6 The manufacturing process was the same as in Comparative Example 1. The difference is that the catalyst slurry prepared in Examples 1-6 was used and the feed rate was 16.0 kg / h.

[0209] Comparative Example 7 The manufacturing process was the same as in Comparative Example 1. The difference is that the catalyst slurry prepared in Examples 1-7 was used and the feed rate was 15.8 kg / h.

[0210] Comparative Example 8 The manufacturing process was the same as in Comparative Example 1. The difference is that the catalyst slurry prepared in Example 1-8 was used and the feed rate was 15.6 kg / h.

[0211] The polypropylene resins produced in the above Comparative Examples 1 to 8 were subjected to performance measurements, and the results are shown in Table 3. [Table 3]

[0212] Comparative Example 9 Propylene prepolymerization: Add 500kg of hexane and 7kg of triethylaluminum solution to the catalyst preparation tank, add 25kg of titanium metal catalyst (Beijing Oda HA-R catalyst) supported by magnesium chloride, stir to form a uniform suspension, use frozen salt water to lower the temperature of the preparation tank below 5℃, add another 1500kg of hexane to adjust the concentration of the catalyst slurry, and stir until it reaches 80r / min. In the first stage of prepolymerization, open the gas phase propylene automatic supply valve, adjust the propylene supply rate to 15kg / h, stir until it reaches 40r / min, lower the temperature of the preparation tank to 5℃, prepolymerize until 100kg of propylene is all consumed, obtain propylene prepolymer slurry, and transfer the above propylene prepolymer slurry to the storage tank for use.

[0213] Liquid phase bulk polymerization: The propylene prepolymer slurry, propylene, cocatalyst, external electron donor and an appropriate amount of hydrogen gas were added to a first-tank reactor to carry out liquid-phase bulk polymerization. The gas-phase propylene was refluxed into the reactor through a tank top cooler. The polymerization temperature was 70°C, the polymerization pressure was 3.0 MPa, the liquid level was 49%, the propylene prepolymer slurry was fed at 14.0 kg / h, the propylene was fed at 5.7 t / h, the triethylaluminum was fed at 0.8 kg / h, the 9,9-di(methoxymethyl)fluorene was fed at 0.07 kg / h, and the hydrogen gas was fed at 4.9 Nm 2 / h, and 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 introduced into the second tank reactor to carry out the polymerization reaction. The temperature of the second tank reactor was 64°C, the polymerization pressure was 2.6MPa, the liquid level was 44%, and hydrogen gas was added to the second tank reactor at a supply rate of 2.0Nm 2 The flow rate of the reaction slurry at the outlet is 4.5t / h, and the hydrogen gas concentration is 1300ppm.

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

[0216] Polypropylene Drying: The material at the outlet of the gas-phase fluidized bed reactor first enters a cyclone separator to separate the material into gas and solid. The separated solid polypropylene powder enters a dryer and is dried by convection nitrogen gas at a drying temperature of 105°C.

[0217] Polypropylene Refining: After drying the polypropylene powder with nitrogen gas, it is transported to a polymer high-purification tank, and a certain amount of composite solvent (a composite solvent of hexane and ethanol, mass ratio 4:1) is added to form a polymer powder slurry with a slurry concentration of 30%, and the polymer is highly purified under a certain process condition (stirring speed 50 rpm, slurry supply rate 20 t / h), the purification temperature is 60 ° C, and the purification time is 0.5 h. The highly purified polymer slurry is centrifuged to obtain polymer wet powder, and the proportion of the solvent in the wet powder is 25%, and it is further subjected to a multi-stage drying (drying temperature 105 ° C) process to remove volatile organic compounds. It is then transported to an extrusion granulation unit to obtain the capacitor film ultra-clean polypropylene resin.

[0218] Extrusion Granulation: The antioxidant complex auxiliary with low ash content and long-term effect (antioxidant 1010 is 2000mg / kg, 168 is 1000mg / kg, calcium stearate is 80mg / kg) and dried polypropylene powder are simultaneously added to a twin-screw extruder and extrusion granulated (granulation temperature is 225℃, screw speed is 120rpm) to obtain ultra-clean polypropylene resin for capacitor film.

[0219] Comparative Example 10 The preparation process is the same as that of Comparative Example 9, except that propylene prepolymerization is not performed.

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

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

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

[0223] The polypropylene resins produced in the above Comparative Examples 9 to 13 were subjected to performance measurements, and the results are shown in Table 4. [Table 4]

[0224] As can be seen from Tables 2 and 4, by adding a propylene prepolymerization process before liquid phase bulk polymerization, the ash content of the produced polypropylene resin is significantly reduced, the electrical properties of the resin are improved, and the fine powder rate of the polypropylene powder is significantly reduced, which is more favorable for the stable operation of the equipment.

[0225] The above examples of the present invention are merely given as examples to clearly explain the present invention, and are not intended to limit the embodiments of the present invention. Those skilled in the art may make other different forms of changes or modifications based on the above description. It is not possible to cover all embodiments here, and all obvious changes or modifications brought about by the technical solutions of the present invention are within the protection scope of the present invention.

Claims

1. A production process including propylene prepolymerization, liquid phase bulk polymerization, gas phase polymerization, polypropylene drying, purification and extrusion granulation, Propylene prepolymerization: A catalyst slurry containing a main catalyst, a cocatalyst and a solvent is prepared in a prepolymerization reactor, and then propylene is introduced to carry out a prepolymerization reaction to obtain a prepolymer slurry; Liquid phase bulk polymerization: Using propylene as raw material, carry out a polymerization reaction in the presence of the prepolymer slurry, a cocatalyst, an external electron donor and hydrogen gas to obtain a polypropylene crude product slurry, wherein the external electron donor is 9,9-di(methoxymethyl)fluorene; Gas phase polymerization: The polypropylene crude product slurry obtained by the liquid phase bulk polymerization is placed in a gas phase fluidized bed reactor to carry out a polymerization reaction; Polypropylene Drying: The outlet material of the gas-phase fluidized bed reactor is first subjected to gas-solid separation, and the solid phase component is put into a dryer to dry it, thereby obtaining polypropylene powder; purification: The dried polypropylene powder is mixed with a composite solvent to prepare a slurry, which is then stirred and purified. The slurry is then subjected to solid-liquid separation to obtain wet polypropylene powder, which is then dried to obtain ultra-clean polypropylene powder; Extrusion granulation: The purified ultra-clean polypropylene powder is mixed with an antioxidant complex auxiliary, and then extrusion granulation is performed to obtain the ultra-clean polypropylene resin. A method for producing an ultra-clean polypropylene resin, comprising the steps of:

2. 2. The method according to claim 1, wherein the prepolymerization reaction includes 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 the prepolymerization time is until all the propylene for prepolymerization is added to the prepolymerization reactor.

3. 3. The method according to claim 1, wherein in the propylene prepolymerization step, the mass ratio of propylene to the main catalyst is 2.5-10 kg / kg, and the mass ratio of the co-catalyst to the main catalyst is 0.027-0.075 kg / kg.

4. 2. The method according to claim 1, wherein the solvent in the catalyst slurry is one or a combination of two or more selected from the group consisting of butane, pentane, hexane, heptane, octane, nonane, and decane.

5. The main catalyst is MgCl 2 Support, TiCl 4 The method according to claim 1, characterized in that the ZN-based catalyst comprises an active center and an internal electron donor, and the internal electron donor is one or a combination of two or more selected from the group consisting of alkyl-substituted 1,3-diethers, aryl-substituted 1,3-diethers, succinic acid esters, malonic acid esters, and diol esters.

6. 2. The process according to claim 1, wherein the co-catalyst is an alkylaluminum compound.

7. The liquid phase bulk polymerization comprises the steps of:

2. The method according to claim 1, wherein propylene, prepolymer slurry, cocatalyst, external electron donor and hydrogen gas are introduced into a first reactor to carry out polymerization reaction at a temperature of 60-75°C and a pressure of 2.5-3.5MPa, the flow rate of the reaction slurry at the outlet of the first reactor is 4.0-4.5g / 10min, and the hydrogen gas concentration in the first reactor is 1000-3000ppm; the reaction slurry is then introduced into a second reactor, hydrogen gas is introduced, and polymerization reaction is carried out at a temperature of 60-75°C and a pressure of 2.5-3.5MPa, the flow rate of the reaction slurry at the outlet of the second reactor is 3.5-4.5g / 10min, and the hydrogen gas concentration in the second reactor is 1000-2000ppm.

8. 8. The process according to claim 1 or 7, characterized in that, in the liquid phase bulk polymerization process, the mass ratio of the main catalyst to propylene is 0.03-0.05 kg / t, the mass ratio of the co-catalyst to propylene is 0.015-0.0225 kg / t, and the mass ratio of the external electron donor to co-catalyst is 0-0.015 kg / kg, not including 0.

9. The method according to claim 1, characterized in that, in the gas phase polymerization process, the polymerization temperature is 75-85°C, the polymerization pressure is 1.5-2.0MPa, the melt flow rate of the polypropylene powder at the outlet of the gas phase fluidized bed reactor is 2.8-3.2g / 10min, the ash content is less than 30ppm, and the isotacticity is greater than 98.5%.

10. The method according to claim 1, characterized in that, in the polypropylene drying process, the solid phase component enters a dryer and is dried by convection nitrogen gas, and the drying temperature is 100 to 110°C.

11. The method according to claim 1, wherein the purification temperature is 30-150°C and the purification time is 0.1-5h.

12. 2. The method according to claim 1, wherein the proportion of the solvent in the wet polypropylene powder is 15 to 35%, based on the total mass of the polypropylene powder being 100%.

13. 2. The method according to claim 1, wherein in the purification step, the mass concentration of the polypropylene powder in the prepared slurry is 10 to 40%.

14. 2. The process of claim 1, wherein the ultra-clean polypropylene powder has an ash content of less than 10 ppm.

15. 2. The method according to claim 1, wherein the composite solvent comprises a hydrocarbon-based substance and an alkyl alcohol, the hydrocarbon-based 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-based substance to the alkyl alcohol is (2-6):

1.

16. 2. The method according to claim 1, wherein the ultra-clean polypropylene resin obtained by the extrusion granulation has an ash content of less than 20 ppm.

17. The antioxidant complex auxiliary includes an acid scavenger, a main antioxidant and an auxiliary antioxidant, the acid scavenger is one or a combination of two or more selected from metal stearates and hydrotalcites, and the mass ratio of the ultra-clean polypropylene powder to the acid scavenger is (10,000 to 100,000):1; the primary antioxidant is one or a combination of a plurality of antioxidants 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)stearyl propionate, 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 primary antioxidant is (1000-10000):1; The method according to claim 1, characterized in that the auxiliary antioxidant is one or a combination of a plurality of antioxidants selected from the group consisting of 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.

18. An ultra-clean polypropylene resin produced by the method according to any one of claims 1 to 17.

19. A step of polymerizing propylene as a raw material to obtain a polypropylene crude product; and refining the resulting polypropylene crude product to obtain said polypropylene resin, The purification step includes adding a crude polypropylene product to a composite solvent, sufficiently contacting the crude polypropylene product with the composite solvent at 30 to 120°C to form a polypropylene slurry, separating the polypropylene and the composite solvent to obtain a polypropylene powder, and drying the polypropylene powder to obtain the polypropylene resin.

20. The method according to claim 19, wherein the composite solvent is a mixed solvent of at least one selected from alkyl alcohols having 1 to 10 carbon atoms and at least one selected from alkanes having 5 to 20 carbon atoms that are liquid at room temperature.

21. 21. The method of claim 19 or 20, wherein the sufficient contacting comprises contacting the polypropylene crude product with the composite solvent under stirring conditions for 0.1 to 5 h.

22. The method according to any one of claims 19 to 21, wherein the mass concentration of polypropylene in the polypropylene slurry is 10 to 40%.

23. The purification step includes separating the polypropylene and the composite solvent by centrifugation to obtain a polypropylene powder, and then drying the polypropylene powder at 95 to 120 ° C. to obtain the polypropylene resin. The method according to any one of claims 19 to 22.

24. The method according to any one of claims 19 to 23, further comprising the step of extrusion granulation of the obtained polypropylene resin and an antioxidant complex aid.

25. The antioxidant complex auxiliary is a combination selected from an acid scavenger, a main antioxidant, and an auxiliary antioxidant, the acid scavenger is one or more combinations selected from a metal stearate and a hydrotalcite, 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)stearyl propionate, 1,3,5-trimethyl-2,4,6-tris(3,5-di-tert-butyl-4-hydroxybenzyl)benzene, and 1,1,3-tris(2-methyl 25. The method according to claim 24, wherein the auxiliary antioxidant is one or a combination of two 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 percentage contents of the acid scavenger, the main antioxidant, and the auxiliary antioxidant are 0.1 to 1%, 65 to 90%, and 9.4 to 34.4%, respectively, based on the total mass of the antioxidant complex auxiliary being 100%.

26. The method according to claim 24 or 25, wherein the mass percentage content of the antioxidant complex auxiliary is 0.2% to 1%, based on the mass of the obtained polypropylene resin being 100%.

27. The step of polymerizing propylene as a raw material includes the following steps: Propylene prepolymerization step: a certain amount of propylene is polymerized in the presence of a main catalyst and a cocatalyst to form a thin polypropylene layer on the surface of the catalyst particles and obtain a prepolymer slurry, wherein the mass ratio of propylene to the main catalyst in the prepolymerization step is 2.5-10 kg / kg, and the mass ratio of the cocatalyst to the main catalyst in the prepolymerization step is 0.18-0.5 kg / kg; Polymerization step: using propylene as a raw material, a polymerization reaction is carried out in the presence of the prepolymer slurry, a cocatalyst, an external electron donor and hydrogen gas to obtain a polypropylene crude product; The method of any one of claims 19 to 26.

28. The production method according to claim 27, wherein the propylene prepolymerization step comprises: introducing propylene at 10-45 kg / h in the presence of a main catalyst and a cocatalyst; polymerizing at -5°C to 15°C for 0.5-3 h; and then introducing propylene at 15-55 kg / h and polymerizing at 5°C to 35°C until all remaining propylene is added to the prepolymerization reactor.

29. The production method according to claim 19 or 28, wherein the propylene prepolymerization step includes adding a main catalyst to a linear or branched alkane having 4 to 10 carbon atoms, so that 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 a polymerization reaction.

30. The method according to any one of claims 27 to 29, wherein the mass ratio of the main catalyst to the propylene added in the polymerization step is 0.03-0.05 kg / t, the mass ratio of the co-catalyst to the propylene added in the polymerization step is 0.1-0.15 kg / t, and the mass ratio of the external electron donor to the co-catalyst added in the polymerization step is 0-0.1 kg / kg.

31. The polymerization step includes the steps of: liquid phase bulk polymerization step: using propylene as a raw material, in the presence of the prepolymer slurry, a cocatalyst, an external electron donor and hydrogen gas, a temperature of 60°C to 75°C and a pressure of 2.5 to 3.5 MPa are included in the liquid phase bulk polymerization step; A gas phase polymerization step includes subjecting the slurry obtained by the liquid phase bulk polymerization to gas phase polymerization at a temperature of 75°C to 85°C and a pressure of 1.5 to 2.0 MPa to obtain a polypropylene crude product; The method of any one of claims 27 to 30.

32. 32. The method of claim 31, wherein the liquid phase bulk polymerization step includes: feeding propylene, prepolymer slurry, cocatalyst, external electron donor and hydrogen gas into a first reactor to carry out a polymerization reaction at a temperature of 60°C-75°C and a pressure of 2.5-3.5MPa, the flow rate of the reaction slurry at the outlet of the first reactor is 4.0-4.5g / 10min, and the hydrogen gas concentration in the first reactor is 1000-3000ppm; then feeding the reaction slurry into a second reactor, introducing hydrogen gas, and carrying out a polymerization reaction at a temperature of 60°C-75°C and a pressure of 2.5-3.5MPa, the flow rate of the reaction slurry at the outlet of the second reactor is 3.5-4.5g / 10min, and the hydrogen gas concentration in the second reactor is 1000-2000ppm.

33. The step of polymerizing propylene as a raw material further includes a step of drying the solid obtained after the polymerization reaction at 95 ° C to 115 ° C, thereby obtaining a crude polypropylene product. The production method according to any one of claims 19 to 32.

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 multiple types selected from cyclohexyldimethoxymethylsilane, p-dicyclopentyldimethoxysilane, diisopropyldimethoxysilane, and diisobutyldimethoxysilane.

35. The ZN-based catalyst is MgCl 2 is used as a support, and TiCl 4 The method according to claim 34, wherein the catalyst is one or a combination of a plurality of catalysts having an active center and an internal electron donor selected from the group consisting of alkyl-substituted 1,3-diethers, aryl-substituted 1,3-diethers, succinic acid esters, and malonic acid esters.

36. 35. The method according to claim 34, wherein the alkylaluminum compound is one or a combination of a plurality of compounds selected from the group consisting of trialkylaluminum, alkylaluminoxane, a combination of trialkylaluminum and alkylaluminum halide, and a combination of trialkylaluminum and alkylaluminum hydride.

37. A polypropylene resin produced by the production method according to any one of claims 19 to 36.

38. 38. The polypropylene resin according to claim 37, wherein the polypropylene resin is obtained by mixing with an antioxidant complex auxiliary and then extrusion granulation, and has an ash content of 30 ppm or less.

Images