Copolymerized high-crystallinity polypropylene material as well as preparation method and application thereof

Abstract

The invention provides a copolymerization type high-crystallinity polypropylene material as well as a preparation method and application thereof. The relative molecular weight distribution PD of the copolymerization type high-crystallinity polypropylene material is 3.5-5; the content XS [%] of a xylene soluble substance is 5-23; the intrinsic viscosity ratio k of the xylene soluble substance to the crystalline phase is 1.6-2.9; the relative molecular weight distribution PD, the crystallization enthalpy delta Hc [kJ / kg], the xylene soluble content XS, the flexural modulus FM [MPa], the simply supported beam impact strength ak [kJ / m < 2 >], the intrinsic viscosity ratio k of the xylene soluble to the crystalline phase and the melt index MFR [g.10 min <-1 > meet a certain relational expression. Tests prove that the copolymerized high-crystallinity polypropylene material has excellent comprehensive properties, such as higher crystallization enthalpy, higher fluidity, higher bending modulus, higher impact strength and the like, and is excellent in processability.

Description

Technical Field

[0001] The invention belongs to the technical field of foaming materials, and specifically relates to a copolymerized high-crystalline polypropylene material and a preparation method and application thereof. Background Art

[0002] Compared with ordinary polypropylene products, high crystalline polypropylene (HCPP) has a higher crystallization temperature, a short product molding cycle, and can meet the production requirements of thin-wall and lightweight. It is widely used in the automotive, home appliance and other fields.

[0003] At present, there are two main ways to prepare highly crystalline polypropylene: (1) using a highly active and high-performance catalyst system and a new polymerization process technology to improve the relative molecular mass distribution of polypropylene and increase the isotacticity of polypropylene, thereby improving the crystallization performance of polypropylene and increasing the melting enthalpy of polypropylene (PP) from the general 65~85 J / g to more than 90 J / g; (2) adding high-end nucleating agents to polypropylene resins to increase the crystallization temperature and crystallization rate of the polymer, change the crystal morphology of polypropylene, and refine the grains.

[0004] However, the rigidity of HCPP prepared by adding nucleating agents alone is limited, and the amount of nucleating agents added is large, resulting in high production costs. Therefore, the mainstream method is to use improved catalysts and polymerization process technologies to prepare high crystalline polypropylene. This method can not only effectively adjust and control the chain structure of polypropylene macromolecules, but also adjust the structure and optimize the performance of PP, thereby reducing costs. Summary of the invention

[0005] In view of this, the object of the present invention is to provide a copolymerized high crystalline polypropylene material and a preparation method and application thereof. The copolymerized high crystalline polypropylene material has a high flexural modulus, good impact resistance and excellent processing performance.

[0006] To achieve this object, the present invention adopts the following technical solutions:

[0007] In the first aspect, the present invention provides a copolymer high crystalline polypropylene material, wherein the copolymer high crystalline polypropylene material is prepared by reacting homopolypropylene, propylene, ethylene and hydrogen to obtain ethylene-propylene copolymer polypropylene; mixing the ethylene-propylene copolymer polypropylene with an additive, extruding and granulating the mixture;

[0008] In the reaction, the molar ratio of ethylene to the total amount of polymerization monomers is (0.2-0.5):1; the molar ratio of hydrogen to the total amount of polymerization monomers is (0-0.02):1;

[0009] The total amount of polymerization monomers is the total amount of ethylene and propylene;

[0010] The relative molecular weight distribution PD of the copolymerized high crystalline polypropylene material is 3.5-5; the content XS[%] of xylene solubles is 5-23; the intrinsic viscosity ratio k of xylene solubles to crystalline phase is 1.6-2.9;

[0011] The crystallization enthalpy ΔH of the copolymerized high crystalline polypropylene material c [kJ / kg] and the relative molecular weight distribution PD satisfy the following formula (1); the flexural modulus FM [MPa] of the copolymerized high crystalline polypropylene material and the content of xylene solubles satisfy the following formula (2); the simply supported beam impact strength a of the copolymerized high crystalline polypropylene material k [kJ / m 2 ] and the content of xylene solubles satisfy the following formula (3); the intrinsic viscosity ratio k and the melt index MFR [g·10min -1 ] satisfies the following formula (4);

[0012] PD 2 +55≤ΔH c ≤PD 2 +98 (1)

[0013] -XS 1.34 +924≤FM≤-XS 2.04 +2300 (2)

[0014] XS 0.22 ≤a k ≤4XS 0.35 (3)

[0015] 4log 1.11 k≤MFR≤7log 1.04 k(4).

[0016] Preferably, the content of xylene solubles, the intrinsic viscosity of xylene solubles and the relative molecular weight distribution PD are all measured using trichlorobenzene as solvent.

[0017] In the present invention, the xylene soluble content and the intrinsic viscosity of the xylene solubles are measured according to method B: infrared spectroscopy in GB∕T 24282-2021 standard, and trichlorobenzene or o-dichlorobenzene can be used as the solvent. Since the standard curve in the xylene soluble tester used is fitted with trichlorobenzene as the solvent, trichlorobenzene is selected as the solvent.

[0018] In the present invention, the relative molecular weight distribution PD is detected according to the SN / T 4183-2015 standard, which stipulates that trichlorobenzene is used as the mobile phase.

[0019] Preferably, the additive is selected from any one or more of an antioxidant, a plasticizer, a filler, a nucleating agent or an antistatic agent.

[0020] Preferably, the antioxidant includes any one or more of antioxidant 1010, antioxidant 3114, antioxidant 1076, antioxidant 168, and antioxidant BHT.

[0021] Preferably, the nucleating agent includes any one or more of sodium benzoate, nucleating agent NA-21, nucleating agent NA-27, and talc.

[0022] In a second aspect, the present invention provides a method for preparing the above copolymerized high crystalline polypropylene material, comprising:

[0023] homopolymerizing propylene in the presence of a catalyst, a co-catalyst, an external electron donor and hydrogen to obtain homopolypropylene;

[0024] The homopolymerized polypropylene is subjected to a gas phase ethylene-propylene copolymerization reaction with propylene, ethylene and hydrogen to obtain ethylene-propylene copolymerized polypropylene;

[0025] The ethylene-propylene copolymerized polypropylene is mixed with additives, extruded and granulated to obtain a copolymerized high-crystalline polypropylene material.

[0026] Preferably, the catalyst is a Ziegler-Natta catalyst.

[0027] Preferably, the Ziegler-Natta catalyst is a porous granular catalyst or a spherical catalyst containing a titanium compound and using a magnesium halide as a carrier.

[0028] Preferably, the titanium compound is selected from any one or more of titanium tetrachloride, titanium tetrabromide or titanium tetraiodide.

[0029] Preferably, the magnesium halide compound is selected from any one or more of magnesium dichloride, magnesium dibromide or magnesium diiodide.

[0030] Preferably, the co-catalyst is an alkyl aluminum compound; the alkyl aluminum compound is selected from any one or more of triisobutyl aluminum, triethyl aluminum, dimethyl aluminum monochloride, diethyl aluminum monochloride or monoisobutyl aluminum dichloride.

[0031] Preferably, the external electron donor is a silicon compound; the silicon compound is selected from any one or more of cyclohexylmethyldimethoxysilane, cyclohexylmethyltrimethoxysilane, dicyclopentyldimethoxysilane, dicyclohexyldimethoxysilane, diisopropyldimethoxysilane or phenyltrimethoxysilane.

[0032] In a third aspect, the present invention provides an application of the above copolymerized high-crystalline polypropylene material in the field of preparing lightweight products.

[0033] Among them, the lightweight products include car dashboards, bumpers or kitchen and bathroom appliances.

[0034] Compared with the prior art, the present invention has the following beneficial effects:

[0035] The present invention provides a copolymerized high-crystalline polypropylene material, wherein the relative molecular weight distribution PD of the copolymerized high-crystalline polypropylene material is 3.5-5; the content XS[%] of xylene solubles is 5-23; the intrinsic viscosity ratio k of xylene solubles to crystalline phase is 1.6-2.9; the crystallization enthalpy ΔH of the copolymerized high-crystalline polypropylene material is c [kJ / kg] and the relative molecular weight distribution PD satisfy the formula (1); the flexural modulus FM [MPa] of the copolymerized high crystalline polypropylene material and the content of xylene solubles satisfy the formula (2); the simply supported beam impact strength a of the copolymerized high crystalline polypropylene material k [kJ / m 2 ] and the content of xylene solubles satisfy formula (3); the intrinsic viscosity ratio k and the melt index MFR satisfy formula (4).

[0036] After testing, it was found that the copolymer high crystalline polypropylene material that meets the above relationship has excellent comprehensive properties, such as higher crystallization enthalpy, higher fluidity, higher bending modulus, higher impact strength, etc., and excellent processing performance. DETAILED DESCRIPTION

[0037] The technical solution of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0038] The present invention provides a copolymerized high-crystalline polypropylene material. The copolymerized high-crystalline polypropylene material is prepared by reacting homopolymerized polypropylene, propylene, ethylene and hydrogen to obtain ethylene-propylene copolymerized polypropylene; mixing the ethylene-propylene copolymerized polypropylene with an additive, extruding and granulating the mixture;

[0039] The additive is used to improve the performance of the polypropylene material, and can be selected from any one or more of an antioxidant, a plasticizer, a filler, a nucleating agent or an antistatic agent, preferably an antioxidant and a nucleating agent. The addition of an antioxidant can ensure the stability of the product; the addition of a nucleating agent can further improve the rigidity of the product. The present invention has no particular restrictions on the source of the above-mentioned additives, and they can be general commercial products.

[0040] In the present invention, in order to ensure that the copolymerized high crystalline polypropylene material has a high flexural modulus, good impact resistance and excellent processing performance, the present invention preferably has a crystallization enthalpy ΔH of the copolymerized high crystalline polypropylene material. c [kJ / kg] and the relative molecular weight distribution PD satisfy the following formula (1); the flexural modulus FM [MPa] of the copolymerized high crystalline polypropylene material and the content of xylene solubles satisfy the following formula (2); the simply supported beam impact strength a of the copolymerized high crystalline polypropylene material k [kJ / m 2 ] and the content of xylene solubles satisfy the following formula (3); the intrinsic viscosity ratio k and the melt index MFR [g·10min -1 ] satisfies the following formula (4);

[0041] PD 2 +55≤ΔH c ≤PD 2 +98 (1)

[0042] -XS 1.34 +924≤FM≤-XS 2.04 +2300 (2)

[0043] XS 0.22 ≤a k ≤4XS 0.35 (3)

[0044] 4log 1.11 k≤MFR≤7log 1.04 k(4).

[0045] In the present invention, the relative molecular weight distribution PD of the copolymerized high crystalline polypropylene material is measured by gel permeation chromatography in SN / T 4183-2015 using trichlorobenzene as solvent. In the present invention, PD is usually 2-6, preferably 3.5-5, and more preferably 3.5-4.

[0046] It should be noted that the crystallization enthalpy ΔHc [kJ / kg] and the relative molecular weight distribution PD of the copolymerized high crystalline polypropylene material of the present invention satisfy the relationship of formula (1):

[0047] PD 2 +55≤ΔH c ≤PD 2 +98 (1)

[0048] In the invention, the copolymerized high crystalline polypropylene material needs to have a high degree of crystallinity. 2When the relationship of +55≤ΔHc is not satisfied, that is, the crystallization enthalpy is too low, the stereoregularity of polypropylene is poor, the crystallinity is low, and it is not conducive to processing; and when ΔHc≤PD in formula (1) 2 When the relationship of +98 is not satisfied, that is, the melting enthalpy is too high, the process is difficult to implement.

[0049] In the present invention, the copolymerized high crystalline polypropylene material preferably satisfies the following relation (1): PD 2 +60≤ΔH c ≤PD 2 +93, preferably: PD 2 +65≤ΔH c ≤PD 2 +88.

[0050] The crystallization enthalpy in the above formula (1) is measured using a differential scanning calorimeter (DSC1) according to the method described in GB / T 19466.3-2004, and the obtained DSC curve is processed.

[0051] In the present invention, the xylene soluble content of the copolymerized high crystalline polypropylene material is measured using 1,2,4-trichlorobenzene as solvent, using a rapid fully automatic polyolefin xylene soluble content analyzer (CRYSTEX QC) according to the mid-infrared spectroscopy method of GB / T 24282-2021.

[0052] It should be noted that the flexural modulus FM [MPa] of the copolymerized high crystalline polypropylene material of the present invention and the xylene soluble content satisfy the relationship of formula (2):

[0053] -XS 1.34 +924≤FM≤-XS 2.04 +2300 (2)

[0054] In the present invention, the copolymerized high crystalline polypropylene material needs to have a suitable and high bending modulus. When the relationship -XS1.34+924≤FM in formula (2) is not satisfied, that is, the bending modulus is low, indicating that the rigidity of the polypropylene is insufficient and cannot meet the rigidity requirements of the overall product after processing; when the relationship FM≤-XS2.04+2300 in formula (2) is not satisfied, that is, the bending modulus is too high, the impact performance is generally poor, and it is difficult to achieve rigidity balance performance.

[0055] In the present invention, the copolymerized high crystalline polypropylene material preferably satisfies the relationship (2): -XS+1005≤FM≤-XS 1.47 +1700, preferably: -XS 1.11 +1106≤FM≤-XS 0.51 +1505.

[0056] The bending modulus in the above formula (2) is measured according to the method described in GB / T 9341-2008. Specifically, a universal tensile testing machine is used to test the three-point loading test method, that is, the standard specimen is supported as a beam, so that it is at the center of the span (64 mm) and at a constant speed (2 mm·min -1 ) until the specimen deformation reaches the specified deflection (6 mm), and the pressure applied to the specimen during this process is measured. The ratio of the stress difference to the corresponding strain difference is the bending modulus in formula (3), with MPa as the unit.

[0057] In the present invention, the simply supported beam impact strength a of the copolymerized high crystalline polypropylene material is k [kJ / m 2 ] and the xylene soluble content satisfy the relationship of formula (3):

[0058] XS 0.22 ≤a k ≤4XS 0.35 (3)

[0059] The copolymerized high crystalline polypropylene material of the present invention needs to have a high impact strength. When XS in formula (3) 0.22 ≤a k When the relationship is not satisfied, that is, the simply supported beam impact strength is low, indicating that the toughness of polypropylene is poor, which limits its application in life; when a in formula (3) k ≤4XS 0.35 When the relationship is not satisfied, that is, the impact strength is too high, the rigidity of the product will be sacrificed.

[0060] In the present invention, the copolymerized high crystalline polypropylene material preferably satisfies the following relation (3): XS 0.35 ≤a k ≤4XS 0.25 , preferably: XS 0.44 ≤a k ≤4XS 0.14 .

[0061] The simply supported beam impact strength in the above formula (3) is tested using a simply supported beam pendulum impact tester (CEAST-9050) according to the method described in GB / T 1043.1-2008. The specific test method is to impact a notched specimen, select an appropriate pendulum, raise it to a fixed height, and impact the specimen supported as a horizontal beam once at a constant speed, with the impact line facing the single notch.

[0062] The intrinsic viscosity of the xylene soluble matter of the copolymerized high crystalline polypropylene material of the present invention and the intrinsic viscosity of the crystalline phase are tested using a rapid fully automatic polyolefin xylene soluble content analyzer (CRYSTEX QC) and measured according to the mid-infrared spectroscopy method in accordance with GB / T24282-2021, and the viscosity ratio k is obtained by further calculation.

[0063] In the present invention, the intrinsic viscosity ratio k of the xylene soluble matter to the crystalline phase of the copolymerized high crystalline polypropylene material is related to the melt index MFR [g·10min -1 ] satisfies the relationship in formula (4):

[0064] 4log 1.11 k≤MFR≤7log 1.04 k (4)

[0065] When the copolymerized high crystalline polypropylene of the present invention satisfies formula (4), the formed high crystalline polymer product has good fluidity and is conducive to molding processing.

[0066] In the present invention, the copolymerized high crystalline polypropylene material preferably satisfies the following relationship (4): 4.5log 1.11 k≤MFR≤6.7log 1.04 k, more preferably: 5.5log 1.11 k≤MFR≤6.5log 1.04 k.

[0067] The melt flow rate in the above formula (4) is measured at 230°C under a load of 2.16 kg according to GB / T 3682.1-2018.

[0068] The present invention also provides a method for preparing the above copolymerized high-crystalline polypropylene material, comprising:

[0069] homopolymerizing propylene in the presence of a catalyst, a co-catalyst, an external electron donor and hydrogen to obtain homopolymerized polypropylene powder;

[0070] Then, homopolymerized polypropylene is subjected to gas phase ethylene-propylene copolymerization reaction with propylene, ethylene and hydrogen in a certain ratio to obtain ethylene-propylene copolymerized polypropylene powder;

[0071] Then the polypropylene powder is mixed with additives, and a copolymerized high-crystalline polypropylene material is obtained through extrusion and granulation.

[0072] In the present invention, the catalyst is a Ziegler-Natta catalyst, which is a porous granular catalyst or a spherical catalyst containing a titanium compound with a magnesium halide as a carrier. The titanium compound is selected from any one or more of titanium tetrachloride, titanium tetrabromide or titanium tetraiodide, preferably titanium tetrachloride. The magnesium halide compound is selected from any one or more of magnesium dichloride, magnesium dibromide or magnesium diiodide, preferably magnesium dichloride.

[0073] In the present invention, the co-catalyst is an alkyl aluminum compound; the alkyl aluminum compound is selected from any one or more of triisobutyl aluminum, triethyl aluminum, dimethyl aluminum chloride, diethyl aluminum chloride or monoisobutyl aluminum dichloride, preferably triethyl aluminum.

[0074] In the present invention, the external electron donor is used to adjust the isotacticity of polypropylene, and can be specifically a silicon compound; the silicon compound is selected from any one or more of cyclohexylmethyldimethoxysilane, cyclohexylmethyltrimethoxysilane, dicyclopentyldimethoxysilane, dicyclohexyldimethoxysilane, diisopropyldimethoxysilane or phenyltrimethoxysilane.

[0075] In the present invention, the temperature of the homopolymerization reaction and the gas-phase ethylene-propylene copolymerization reaction should be lower than the melting temperature of the copolymerized high crystalline polypropylene material. Specifically, in the present invention, the temperature of the homopolymerization reaction and the temperature of the gas-phase ethylene-propylene copolymerization reaction are independently 0-150° C., preferably 30-100° C., and more preferably 60-90° C. The time of the homopolymerization reaction is 0.2-5 h, preferably 0.5-2 h, and the time of the gas-phase ethylene-propylene copolymerization reaction is 0.1-2 h, preferably 0.1-1 h.

[0076] In the present invention, the polymerization process of the homopolymerization reaction is a bulk polymerization process, which can be a direct polymerization method or a two-stage polymerization method. The present invention has no particular restrictions on the direct polymerization method or the two-stage polymerization method, and conventional technical solutions well known to those skilled in the art can be used. Among them, in the present invention, the two-stage polymerization method divides the polymerization process into bulk polymerization and gas-phase ethylene-propylene copolymerization polymerization. Therefore, the present invention preferably uses a two-stage polymerization method.

[0077] In some preferred embodiments of the present invention, the preparation method of the copolymer high crystalline polypropylene material adopts two reactors in series operation, firstly, monomer propylene, Ziegler-Natta catalyst, alkyl aluminum co-catalyst, external electron donor and hydrogen are added to the first reactor to carry out bulk polymerization to generate homopolypropylene (in the form of powder); the homopolypropylene is transferred to the gas phase reactor under the action of pressure difference, and the transferred homopolypropylene powder continues to react with ethylene, propylene and hydrogen added to the gas phase reactor by utilizing the residual activity of the catalyst to generate ethylene-propylene copolymer polypropylene powder; then, after adding a variety of additives, extrusion and granulation are carried out to obtain copolymer high crystalline polypropylene.

[0078] In the present invention, the first reactor and the gas phase reactor are any one of a kettle reactor (such as a stainless steel pressure reactor), a tubular reactor, a multi-zone circulation reactor or a stirred tank reactor with a temperature control jacket and a mechanical stirring device, preferably a kettle reactor.

[0079] In some embodiments of the present invention, after the reaction in the gas phase reactor is completed, unreacted propylene, ethylene and hydrogen are preferably removed under reduced pressure to obtain copolymerized high crystalline polypropylene powder, and then a variety of additives are added and the powder is granulated using a twin-screw extruder to obtain a copolymerized high crystalline polypropylene material. The selection of the additives is as described in the above-mentioned related content and will not be repeated here.

[0080] In some preferred embodiments of the present invention, the method for preparing the copolymerized high crystalline polypropylene material comprises:

[0081] S1: In a first reactor, propylene bulk polymerization is carried out to homopolymerize propylene in the presence of a catalyst, a co-catalyst, an external electron donor and hydrogen to obtain homopolymerized polypropylene powder;

[0082] S2: In a gas phase reactor, a gas phase ethylene-propylene copolymerization reaction is carried out, the homopolymerized polypropylene powder with active centers is transferred into the gas phase reactor, and propylene, ethylene and hydrogen are introduced at a certain ratio to carry out copolymerization reaction to obtain ethylene-propylene copolymerized polypropylene powder;

[0083] S3: After mixing the ethylene-propylene copolymer polypropylene powder with the additive, extruding and granulating, a copolymerized high-crystalline polypropylene material is obtained.

[0084] Wherein, the molar ratio of ethylene / total amount of polymerizable monomers in step S2 is 20% to 50%, and the molar ratio of hydrogen / total amount of polymerizable monomers is 0% to 2%. In the present invention, the total amount of polymerizable monomers is the total amount of ethylene and propylene.

[0085] In some specific embodiments of the present invention, the method for preparing the copolymerized high crystalline polypropylene material comprises:

[0086] Refining sufficient amounts of liquid propylene and ethylene respectively through the refining system. Raise the temperature of the jacketed stainless steel pressure polymerization kettle with mechanical stirring (first reactor) to 60-90°C, replace with high-purity nitrogen and vacuumize, and then cool to 25°C for standby use. In the first reactor, a first-stage reaction is carried out: propylene monomer, Ziegler-Natta catalyst, alkyl aluminum cocatalyst, external electron donor and hydrogen are added to the reactor in sequence, the reactor is heated to 60-90°C, and the reaction is carried out at a constant temperature for 0.5-2 h. After the first-stage reaction is completed, the pressure in the reactor is completely emptied, and then the polypropylene powder is discharged into a jacketed stainless steel pressure polymerization reactor (gas phase reactor) with mechanical stirring under the action of pressure difference. After the pressure is balanced, the pressure of the gas phase reactor is emptied to zero, and the feed is fed at a 40% ethylene molar ratio and a 0.25% hydrogen ratio, so that the pressure rises rapidly to 1-1.8 MPa, and the reactor is heated to 75°C, and the reaction is carried out at a constant temperature for 0.1-1 h. After the second-stage reaction is completed, the pressure in the reactor is emptied, and high-purity nitrogen is used for replacement 2-3 times, and the reactor is cooled to room temperature. The obtained ethylene-propylene copolymer powder is extruded and granulated after adding additives, and the granules are injection molded into standard specimens. In addition, the copolymerized high-crystalline polypropylene material prepared by the present invention is a mixture, which contains propylene homopolymer, propylene-ethylene random copolymer, and propylene-ethylene multi-block copolymer; the mixture also contains the additives involved in the above scheme.

[0087] The preparation method of the copolymerized high crystalline polypropylene material provided by the present invention is simple, the product molding cycle is short, and it is easy to implement, which is conducive to industrialization or industrial production. The prepared copolymerized high crystalline polypropylene material has excellent comprehensive properties, such as higher crystallization enthalpy, higher fluidity, higher bending modulus, higher impact strength, etc.

[0088] Based on this, the present invention also provides an application of the above copolymerized high-crystalline polypropylene material in the field of preparing lightweight products.

[0089] The lightweight products include but are not limited to automobile dashboards, bumpers or kitchen and bathroom appliances.

[0090] In order to further illustrate the present invention, the following examples are used to explain it in detail. The experimental raw materials used in the following examples of the present invention are all common commercial products. The total amount of polymerization monomers involved in the following examples is the total amount of ethylene and propylene.

[0091] Example 1

[0092] A sufficient amount of liquid propylene and ethylene were purified by the refining system. A 10 L jacketed stainless steel pressure polymerization reactor with mechanical stirring (first reactor) was heated to 60°C, replaced with high-purity nitrogen and vacuumed, and then cooled to 25°C for standby use. A first-stage reaction was carried out in the first reactor: 3.5 kg of propylene monomer, 0.021 g of HR catalyst, 11 mL of triethylaluminum, 0.06 mL of external electron donor (dicyclopentyldimethoxysilane) and 2.3 g of hydrogen were added to the reactor in sequence, the reactor was heated to 70°C, and the reaction was carried out at a constant temperature for 1 h. After the first-stage reaction was completed, the pressure in the reactor was completely evacuated, and then the polypropylene powder was transferred to a 20 L jacketed stainless steel pressure polymerization reactor (gas phase reactor) with mechanical stirring under the action of pressure difference. After the pressure was balanced, the pressure of the gas phase reactor was evacuated to zero, and the feed was fed at a molar ratio of 40% ethylene / total amount of polymerization monomer and 0.25% hydrogen / total amount of polymerization monomer, so that the pressure rose rapidly to 1.4 MPa, the reactor was heated to 75°C, and the reaction was carried out at a constant temperature for 0.75 h. After the second-stage reaction was completed, the pressure in the reactor was evacuated, and high-purity nitrogen was used to replace it 3 times, and the reactor was cooled to room temperature. The obtained ethylene-propylene copolymer powder was added with antioxidant 1010, antioxidant 168 and nucleating agent sodium benzoate, and then extruded into granules, and the granules were injection molded into standard specimens. The evaluation results of the physical properties of the obtained copolymer are shown in Table 1.

[0093] Example 2

[0094] A sufficient amount of liquid propylene and ethylene were purified by the refining system. A 10 L jacketed stainless steel pressure polymerization reactor with mechanical stirring (first reactor) was heated to 60°C, replaced with high-purity nitrogen and vacuumed, and then cooled to 25°C for standby use. A first-stage reaction was carried out in the first reactor: 3.5 kg of propylene monomer, 0.021 g of HR catalyst, 11 mL of triethylaluminum, 0.06 mL of external electron donor (dicyclopentyldimethoxysilane) and 2.3 g of hydrogen were added to the reactor in sequence, the reactor was heated to 70°C, and the reaction was carried out at a constant temperature for 1 h. After the first-stage reaction was completed, the pressure in the reactor was completely evacuated, and then the polypropylene powder was transferred to a 20 L jacketed stainless steel pressure polymerization reactor (gas phase reactor) with mechanical stirring under the action of pressure difference. After the pressure was balanced, the pressure of the gas phase reactor was evacuated to zero, and the feed was fed at a molar ratio of 35% ethylene / total amount of polymerization monomer and 0.25% hydrogen / total amount of polymerization monomer, so that the pressure rose rapidly to 1.4 MPa, the reactor was heated to 75°C, and the reaction was carried out at a constant temperature for 0.75 h. After the second-stage reaction was completed, the pressure in the reactor was evacuated, and high-purity nitrogen was used to replace it 3 times, and the reactor was cooled to room temperature. The obtained ethylene-propylene copolymer powder was added with antioxidant 1010, antioxidant 168 and nucleating agent sodium benzoate, and then extruded into granules, and the granules were injection molded into standard specimens. The evaluation results of the physical properties of the obtained copolymer are shown in Table 1.

[0095] Example 3

[0096] A sufficient amount of liquid propylene and ethylene were purified by the refining system. A 10 L jacketed stainless steel pressure polymerization reactor with mechanical stirring (first reactor) was heated to 60°C, replaced with high-purity nitrogen and vacuumed, and then cooled to 25°C for standby use. A first-stage reaction was carried out in the first reactor: 3.5 kg of propylene monomer, 0.021 g of HR catalyst, 11 mL of triethylaluminum, 0.06 mL of external electron donor (dicyclopentyldimethoxysilane) and 2.3 g of hydrogen were added to the reactor in sequence, the reactor was heated to 70°C, and the reaction was carried out at a constant temperature for 1 h. After the first-stage reaction was completed, the pressure in the reactor was completely evacuated, and then the polypropylene powder was transferred to a 20 L jacketed stainless steel pressure polymerization reactor (gas phase reactor) with mechanical stirring under the action of pressure difference. After the pressure was balanced, the pressure of the gas phase reactor was evacuated to zero, and the feed was fed at a molar ratio of 30% ethylene / total amount of polymerization monomer and 0.25% hydrogen / total amount of polymerization monomer, so that the pressure rose rapidly to 1.4 MPa, the reactor was heated to 75°C, and the reaction was carried out at a constant temperature for 0.75 h. After the second-stage reaction was completed, the pressure in the reactor was evacuated, and high-purity nitrogen was used to replace it 3 times, and the reactor was cooled to room temperature. The obtained ethylene-propylene copolymer powder was added with antioxidant 1010, antioxidant 168 and nucleating agent sodium benzoate, and then extruded into granules, and the granules were injection molded into standard specimens. The evaluation results of the physical properties of the obtained copolymer are shown in Table 1.

[0097] Example 4

[0098] A sufficient amount of liquid propylene and ethylene were purified by the refining system. A 10 L jacketed stainless steel pressure polymerization reactor with mechanical stirring (first reactor) was heated to 60°C, replaced with high-purity nitrogen and vacuumed, and then cooled to 25°C for standby use. A first-stage reaction was carried out in the first reactor: 3.5 kg of propylene monomer, 0.021 g of HR catalyst, 11 mL of triethylaluminum, 0.06 mL of external electron donor (dicyclopentyldimethoxysilane) and 2.3 g of hydrogen were added to the reactor in sequence, the reactor was heated to 70°C, and the reaction was carried out at a constant temperature for 1 h. After the first-stage reaction was completed, the pressure in the reactor was completely evacuated, and then the polypropylene powder was transferred to a 20 L jacketed stainless steel pressure polymerization reactor (gas phase reactor) with mechanical stirring under the action of pressure difference. After the pressure was balanced, the pressure of the gas phase reactor was evacuated to zero, and the feed was fed at a molar ratio of 40% ethylene / total amount of polymerization monomer and 0.25% hydrogen / total amount of polymerization monomer, so that the pressure rose rapidly to 1.4 MPa, the reactor was heated to 75°C, and the reaction was carried out at a constant temperature for 0.3 h. After the second-stage reaction was completed, the pressure in the reactor was evacuated, and high-purity nitrogen was used to replace it 3 times, and the reactor was cooled to room temperature. The obtained ethylene-propylene copolymer powder was added with antioxidant 1010, antioxidant 168 and nucleating agent sodium benzoate, and then extruded into granules, and the granules were injection molded into standard specimens. The evaluation results of the physical properties of the obtained copolymer are shown in Table 1.

[0099] Example 5

[0100] A sufficient amount of liquid propylene and ethylene were purified by the refining system. A 10 L jacketed stainless steel pressure polymerization reactor with mechanical stirring (first reactor) was heated to 60°C, replaced with high-purity nitrogen and vacuumed, and then cooled to 25°C for standby use. A first-stage reaction was carried out in the first reactor: 3.5 kg of propylene monomer, 0.021 g of HR catalyst, 11 mL of triethylaluminum, 0.06 mL of external electron donor (dicyclopentyldimethoxysilane) and 2.3 g of hydrogen were added to the reactor in sequence, the reactor was heated to 70°C, and the reaction was carried out at a constant temperature for 1 h. After the first-stage reaction was completed, the pressure in the reactor was completely evacuated, and then the polypropylene powder was discharged into a 20 L jacketed stainless steel pressure polymerization reactor (gas phase reactor) with mechanical stirring under the action of pressure difference. After the pressure was balanced, the pressure of the gas phase reactor was evacuated to zero, and the feed was fed at a molar ratio of 40% ethylene / total amount of polymerization monomer and 0.5% hydrogen / total amount of polymerization monomer, so that the pressure rose rapidly to 1.4 MPa, the reactor was heated to 75°C, and the reaction was carried out at a constant temperature for 0.3 h. After the second-stage reaction was completed, the pressure in the reactor was evacuated, and high-purity nitrogen was used to replace it 3 times, and the reactor was cooled to room temperature. The obtained ethylene-propylene copolymer powder was added with antioxidant 1010, antioxidant 168 and nucleating agent sodium benzoate, and then extruded into granules, and the granules were injection molded into standard specimens. The evaluation results of the physical properties of the obtained copolymer are shown in Table 1.

[0101] Example 6

[0102] A sufficient amount of liquid propylene and ethylene were purified by the refining system. A 10 L jacketed stainless steel pressure polymerization reactor with mechanical stirring (first reactor) was heated to 60°C, replaced with high-purity nitrogen and vacuumed, and then cooled to 25°C for standby use. A first-stage reaction was carried out in the first reactor: 3.5 kg of propylene monomer, 0.021 g of HR catalyst, 11 mL of triethylaluminum, 0.06 mL of external electron donor (dicyclopentyldimethoxysilane) and 2.3 g of hydrogen were added to the reactor in sequence, the reactor was heated to 70°C, and the reaction was carried out at a constant temperature for 1 h. After the first-stage reaction was completed, the pressure in the reactor was completely evacuated, and then the polypropylene powder was discharged into a 20 L jacketed stainless steel pressure polymerization reactor (gas phase reactor) with mechanical stirring under the action of pressure difference. After the pressure was balanced, the pressure of the gas phase reactor was evacuated to zero, and the material was fed at a molar ratio of 40% ethylene / total amount of polymerization monomers to rapidly increase the pressure to 1.4 MPa. The reactor was heated to 75°C and the reaction was carried out at a constant temperature for 0.3 h. After the second-stage reaction was completed, the pressure in the reactor was evacuated, and high-purity nitrogen was used to replace it 3 times, and the reactor was cooled to room temperature. The obtained ethylene-propylene copolymer powder was added with antioxidant 1010, antioxidant 168 and nucleating agent sodium benzoate, and then extruded into granules, and the granules were injection molded into standard specimens. The evaluation results of the physical properties of the obtained copolymer are shown in Table 1.

[0103] Comparative Example 1

[0104] A sufficient amount of liquid propylene and ethylene were purified by the refining system. The 10L jacketed stainless steel pressure polymerization kettle with mechanical stirring (first reactor) was heated to 60°C, replaced with high-purity nitrogen and vacuumed, and then cooled to 25°C for standby use. A first-stage reaction was carried out in the first reactor: 3.5 kg of propylene monomer, 0.021 g of HR catalyst, 11 mL of triethylaluminum, 0.06 mL of external electron donor (dicyclopentyldimethoxysilane) and 2.3 g of hydrogen were added to the reactor in sequence, the reactor was heated to 70°C, and the reaction was carried out at a constant temperature for 1 hour. After the first-stage reaction was completed, the pressure in the reactor was completely evacuated, and then the polypropylene powder was transferred to a 20L jacketed stainless steel pressure polymerization reactor (gas phase reactor) with mechanical stirring under the action of pressure difference. After the pressure was balanced, the pressure of the gas phase reactor was evacuated to zero, and the feed was fed at a molar ratio of 40% ethylene / total amount of polymerization monomer and 0.25% hydrogen / total amount of polymerization monomer, so that the pressure rose rapidly to 1.4 MPa, the reactor was heated to 75°C, and the reaction was carried out at a constant temperature for 0.83 h. After the second-stage reaction was completed, the pressure in the reactor was evacuated, and high-purity nitrogen was used for replacement 3 times, and the reactor was cooled to room temperature. The obtained ethylene-propylene copolymer powder was added with antioxidant 1010, antioxidant 168 and nucleating agent sodium benzoate, and then extruded into granules, and the granules were injection molded into standard specimens. The evaluation results of the physical properties of the obtained copolymer are shown in Table 1.

[0105] Comparative Example 2

[0106] A sufficient amount of liquid propylene and ethylene were purified by the refining system. The 10L jacketed stainless steel pressure polymerization kettle with mechanical stirring (first reactor) was heated to 60°C, replaced with high-purity nitrogen and vacuumed, and then cooled to 25°C for standby use. A first-stage reaction was carried out in the first reactor: 3.5 kg of propylene monomer, 0.021 g of HR catalyst, 11 mL of triethylaluminum, 0.06 mL of external electron donor (dicyclopentyldimethoxysilane) and 2.3 g of hydrogen were added to the reactor in sequence, the reactor was heated to 70°C, and the reaction was carried out at a constant temperature for 1 hour. After the first-stage reaction was completed, the pressure in the reactor was completely evacuated, and then the polypropylene powder was discharged into a 20L jacketed stainless steel pressure polymerization reactor (gas phase reactor) with mechanical stirring under the action of pressure difference. After the pressure was balanced, the pressure of the gas phase reactor was evacuated to zero, and the feed was fed at a molar ratio of 40% ethylene / total amount of polymerization monomer and 0.25% hydrogen / total amount of polymerization monomer, so that the pressure rose rapidly to 1.4 MPa, the reactor was heated to 75°C, and the reaction was carried out at a constant temperature for 1 hour. After the second-stage reaction was completed, the pressure in the reactor was evacuated, and high-purity nitrogen was used for replacement 3 times, and the reactor was cooled to room temperature. The obtained ethylene-propylene copolymer powder was added with antioxidant 1010, antioxidant 168 and nucleating agent sodium benzoate, and then extruded into granules, and the granules were injection molded into standard specimens. The evaluation results of the physical properties of the obtained copolymer are shown in Table 1.

[0107] Table 1

[0108]

[0109] From the data in Table 1, we can see that when the molecular weight distribution is around 4, the crystallization enthalpy is high, the crystallinity is good, and it is conducive to processing; when the xylene soluble content is between 13% and 20%, the intrinsic viscosity ratio is between 1.8 and 2.9, the flexural modulus is between 900 MPa and 1650 MPa, and the impact performance is between 5 and 11 kJ / m 2 The melt index is around 55 g / 10min, which indicates that polypropylene has good fluidity and excellent rigidity-toughness balance, and can simultaneously meet the overall requirements of the processed products for rigidity and toughness.

[0110] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A copolymerized high crystalline polypropylene material, characterized in that: The copolymerized high crystalline polypropylene material is prepared by reacting homopolymerized polypropylene, propylene, ethylene and hydrogen to obtain ethylene-propylene copolymerized polypropylene; the ethylene-propylene copolymerized polypropylene is mixed with additives, extruded and granulated. In the reaction, the molar ratio of ethylene to the total amount of polymerization monomers is (0.2-0.5):1; the molar ratio of hydrogen to the total amount of polymerization monomers is (0-0.02):1; The total amount of polymerization monomers is the total amount of ethylene and propylene; The relative molecular weight distribution PD of the copolymerized high crystalline polypropylene material is 3.5-5; the content XS[%] of xylene solubles is 5-23; the intrinsic viscosity ratio k of xylene solubles to the crystalline phase is 1.6-2.9; The crystallization enthalpy ΔH of the copolymerized high crystalline polypropylene material c [kJ / kg] and the relative molecular weight distribution PD satisfy the following formula (1); the flexural modulus FM [MPa] of the copolymerized high crystalline polypropylene material and the content of xylene solubles satisfy the following formula (2); the simply supported beam impact strength a of the copolymerized high crystalline polypropylene material k [kJ / m 2 ] and the content of xylene solubles satisfy the following formula (3); the intrinsic viscosity ratio k and the melt index MFR satisfy the following formula (4); PD 2 +55≤ΔH c ≤PD 2 +98(1) -XS 1.34 +924≤FM≤-XS 2.04 +2300(2) XS 0.22 ≤a k ≤4XS 0.35 (3) 4log 1.11 k≤MFR≤7log 1.04 k(4)。 2. The copolymerized high crystalline polypropylene material according to claim 1, characterized in that: The content of xylene soluble matter, the intrinsic viscosity of xylene soluble matter and the relative molecular weight distribution PD are all measured using trichlorobenzene as solvent.

3. The copolymerized high crystalline polypropylene material according to claim 1 or 2, characterized in that: The additive is selected from any one or more of an antioxidant, a plasticizer, a filler, a nucleating agent or an antistatic agent.

4. The copolymerized high crystalline polypropylene material according to claim 3, characterized in that: The antioxidant includes any one or more of antioxidant 1010, antioxidant 3114, antioxidant 1076, antioxidant 168, and antioxidant BHT.

5. The copolymerized high crystalline polypropylene material according to claim 3 or 4, characterized in that: The nucleating agent includes any one or more of sodium benzoate, nucleating agent NA-21, nucleating agent NA-27, and talc.

6. A method for preparing a copolymerized high crystalline polypropylene material as claimed in any one of claims 1 to 5, characterized in that: include: homopolymerizing propylene in the presence of a catalyst, a co-catalyst, an external electron donor and hydrogen to obtain homopolypropylene; The homopolymerized polypropylene is subjected to a gas phase ethylene-propylene copolymerization reaction with propylene, ethylene and hydrogen to obtain ethylene-propylene copolymerized polypropylene; The ethylene-propylene copolymerized polypropylene is mixed with additives, extruded and granulated to obtain a copolymerized high-crystalline polypropylene material.

7. The preparation method according to claim 6, characterized in that: The catalyst is a Ziegler-Natta catalyst; The Ziegler-Natta catalyst is a porous granular catalyst or a spherical catalyst containing a titanium compound and using a magnesium halide as a carrier; The titanium compound is selected from any one or more of titanium tetrachloride, titanium tetrabromide or titanium tetraiodide; The magnesium halide compound is selected from any one or more of magnesium dichloride, magnesium dibromide or magnesium diiodide.

8. The preparation method according to claim 6 or 7, characterized in that: The co-catalyst is an alkyl aluminum compound; the alkyl aluminum compound is selected from any one or more of triisobutyl aluminum, triethyl aluminum, dimethyl aluminum chloride, diethyl aluminum chloride or monoisobutyl aluminum dichloride; The external electron donor is a silicon compound; the silicon compound is selected from any one or more of cyclohexylmethyldimethoxysilane, cyclohexylmethyltrimethoxysilane, dicyclopentyldimethoxysilane, dicyclohexyldimethoxysilane, diisopropyldimethoxysilane or phenyltrimethoxysilane.

9. Use of the copolymerized high crystalline polypropylene material according to any one of claims 1 to 5 or the copolymerized high crystalline polypropylene material prepared by the preparation method according to any one of claims 6 to 8 in the field of preparing lightweight products.

10. The use according to claim 9, characterized in that: The lightweight products include automobile dashboards, bumpers or kitchen and bathroom appliances.

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