Polypropylene, and preparation method therefor and use thereof

Abstract

The present invention relates to the field of olefin polymerization, and discloses polypropylene, and a preparation method therefor and the use thereof. In the polypropylene, the molar content of mm is less than or equal to 97.4%, the molar content of mmmm is greater than or equal to 91.6%, and the ratio of the molar content of mmmm to the molar content of mm is greater than or equal to 95.85%; and the half-peak width of a melting peak of the polypropylene is greater than or equal to 6°C. The polypropylene provided by the present invention has both a relatively high nominal strain at tensile fracture and a relatively high stress at tensile fracture, and when used in the production of spunbond fibers or flat filament products, the obtained products have good spinnability, good elongation at break and good breaking strength.

Description

Polypropylene, its preparation methods and applications

[0001] Cross-reference of related applications

[0002] This application claims the benefit of Chinese Patent Application No. 202410696172.0, filed on May 31, 2024, and Chinese Patent No. 202410703017.7, filed on May 31, 2024, the contents of which are incorporated herein by reference. Technical Field

[0003] This invention relates to the field of olefin polymerization, specifically to a polypropylene, its preparation method and application, and a polypropylene fiber and / or polypropylene fiber products. Background Technology

[0004] In the field of flat yarns and fibers, elongation at break or nominal strain at tensile break is an important performance indicator that characterizes the toughness of resin products. Resins with high nominal strain at tensile break result in fewer yarn breaks during later processing, better spinnability, and better maintenance of product strength and quality, as well as a softer feel.

[0005] Due to the excellent comprehensive properties of polypropylene resin, including acid and alkali resistance, abrasion resistance, high strength, and light weight, the application fields of polypropylene fibers and flat yarns are gradually expanding. For example, polypropylene resin is used in geotextiles. Geotextile products represent an extension of spunbond fiber applications in the geotechnical field. They are widely used in railways, airports, highways, and tunnels, requiring products to possess both high elongation at break and high tensile strength, which places high demands on the resin product. For polypropylene resin, it is difficult to simultaneously satisfy both high nominal strain at break and high tensile stress at break. Increasing the nominal strain at break of polypropylene resin often leads to a decrease in tensile stress at break.

[0006] Therefore, developing a novel polypropylene resin with high nominal tensile fracture strain and its preparation method is of great practical significance. Summary of the Invention

[0007] The purpose of this invention is to overcome the problem of poor balance between nominal strain and tensile stress at tensile fracture in polypropylene resin in the prior art, and to provide a polypropylene, its preparation method and application, as well as a polypropylene fiber and / or polypropylene fiber product, wherein the polypropylene has a relatively low content of the mm component and a relatively high content of the mm-mm component, and has a high ratio of the mm-mm component content to the mm component content, which is beneficial to simultaneously improve the nominal strain and tensile stress at tensile fracture of polypropylene.

[0008] To achieve the above objectives, the first aspect of the present invention provides a polypropylene, wherein the polypropylene has a molar content of mm less than or equal to 97.4%, a molar content of mmmm greater than or equal to 91.6%, and a molar content of mmmm to the molar content of mm greater than or equal to 95.85%; and the polypropylene has a melting peak half-width of greater than or equal to 6°C.

[0009] A second aspect of the present invention provides a method for preparing polypropylene, wherein the method comprises the following steps: polymerizing a propylene-containing material in the presence of hydrogen and a catalyst system; wherein,

[0010] The catalyst system comprises: a titanium-containing catalyst, alkyl aluminum, and an optional external electron donor; wherein the titanium-containing catalyst is prepared from a mixture of components A, B, C, magnesium halides and / or magnesium halide adducts, and titanium-containing compounds.

[0011] The preparation method of the titanium-containing catalyst includes:

[0012] Step (1): Optionally, prepare magnesium halide adducts;

[0013] Step (1): Mix component A, component B, component C, magnesium halide and / or the magnesium halide adduct and titanium-containing compound;

[0014] Component A is selected from at least one of hydroxybenzoyl compounds, component B is selected from at least one of alkoxybenzoyl compounds, and component C is selected from at least one of ester compounds and / or ether compounds, wherein component C is different from components A and components B.

[0015] A third aspect of the present invention provides a polypropylene prepared by the preparation method provided by the present invention.

[0016] A fourth aspect of the present invention provides polypropylene fibers and / or polypropylene fiber products prepared from the polypropylene provided by the present invention.

[0017] The fifth aspect of the present invention provides the application of polypropylene with a molar content of mm less than or equal to 97.4%, a molar content of mmmm greater than or equal to 91.6%, a molar content of mmmm to a molar content of mm greater than or equal to 95.85%, and a half-peak width of the melt peak greater than or equal to 6°C in polypropylene fibers and / or polypropylene fiber products.

[0018] The beneficial effects of the present invention through the above technical solution include at least the following:

[0019] The polypropylene resin of this invention has a relatively low content of the mm component and a relatively high content of the mmmm component, a high ratio of mmmm molar content to mm molar content, and a relatively high melt peak half-width. This provides the resin with high elongation at break or nominal tensile strain at break, making the resin less prone to filament breakage during spinning and resulting in resin products with good toughness. Simultaneously, the resin also has high tensile stress at break, which can significantly improve the tensile strength of the product after physical stretching during subsequent processing. When used in film production, the polypropylene resin of this invention can also effectively mitigate necking and improve the strength of the film product. In a preferred embodiment, the lower melting enthalpy, wider melt half-width, and unique intrinsic viscosity of the polypropylene resin of this invention further enhance the balance between the nominal tensile strain at break and the tensile stress at break. Attached Figure Description

[0020] Figure 1 is a DSC curve of the polypropylene prepared in Example 1, Example 9 and Comparative Example 8. Detailed Implementation

[0021] The first aspect of the present invention provides a polypropylene, wherein the polypropylene has a molar content of mm less than or equal to 97.4%, a molar content of mmmm greater than or equal to 91.6%, and a molar content of mmmm to mm greater than or equal to 95.85%; and the polypropylene has a half-peak width of 6°C or greater than or equal to 6°C.

[0022] In this invention, the polypropylene can be homopolymer polypropylene and / or random copolymer polypropylene.

[0023] 13 C10 NMR is an effective method for directly indicating the stereoregularity of polypropylene molecular chains. 13 In C10 NMR studies, structures with adjacent methyl groups located on the same side of the molecular chain and those on different sides are typically denoted as meso (m) and racemic (r), respectively. Isotactic structures can be represented as mmmmmm… Since the number of structural units observed by NMR is limited, ternary sets mm or quinary sets mmmm are commonly used to represent the regularity of the molecular chain.

[0024] In this invention, the half-peak width of the melting peak of polypropylene refers to the peak width at half the height of the melting peak in the melting endothermic curve obtained by DSC testing of polypropylene.

[0025] In the melting endothermic curve obtained by DSC test, the endothermic effect is characterized by the area of ​​the bulging peak (enthalpy of fusion).

[0026] In one specific embodiment of the present invention, DSC can be performed using a Perkin-Elmer DSC-7 differential scanning calorimeter. The sample is heated to 200°C at a rate of 10°C / min, held for 5 min, then cooled to 50°C at a rate of 10°C / min, held at 50°C for 1 min, and then heated back to 200°C at a rate of 10°C / min. The DSC result is plotted on the ordinate as dH / dt heat flow rate and on the abscissa as temperature (T). The endothermic effect is characterized by the area of ​​the peak (enthalpy of fusion). The heating curve is the curve of the second heating (usually the second heating curve is used to eliminate the thermal history of the test sample). As is generally expressed, T... m Indicates the melting point of the test sample, ΔH m This represents the enthalpy of fusion. In the endothermic curve of the polypropylene melt, a straight line parallel to the base of the melt peak is drawn through the midpoint of the peak height. The distance between this straight line and the points where it intersects the two sides of the melt peak is the half-peak width.

[0027] In this invention, a relatively low content of the mm component is beneficial to increasing the nominal strain at tensile break of polypropylene, while a relatively high content of the mm mm component is beneficial to increasing the tensile stress at tensile break of polypropylene. A relatively high ratio of mm mm molar content to mm molar content, along with a relatively high half-peak width of the melt peak, effectively improves the high-level uniformity of nominal strain at tensile break and tensile stress at tensile break of polypropylene; that is, the polypropylene can simultaneously possess both high nominal strain at tensile break and high tensile stress at tensile break. When the polypropylene of this invention with the above characteristics is used to produce spunbond fibers or flat filament products, the resulting products have better spinnability and good nominal strain at tensile break and tensile stress at tensile break.

[0028] In this invention, the molar content of mm in the polypropylene is less than or equal to 97.4%, for example, it can be 97.4%, 97.3%, 97.2%, 97.1%, 97%, 96.9%, 96.8%, 96.7%, 96.6%, 96.5%, 96.4%, 96.3%, 96.2%, 96.1%, 96%, 95.9%, 95.8%, 95.7%, 95.6%, 95.5%, 95.4%, 95.3%, 95.2%, 95.1%, 95%, 94.9%, 94.8%, or 94.7%. , 94.6%, 94.5%, 94.4%, 94.3%, 94.2%, 94.1%, 94%, 93.9%, 93.8%, 93.7%, 93.6%, 93.5%, 93.4%, 93.3%, 93.2%, 93.1%, 93%, 92.9%, 92.8%, 92.7%, 92.6%, 92.5%, 92.4%, 92.3%, 92.2%, 92.1%, 92%, 91.9%, 91.8%, 91.7%, 91.6%, and the range of any two values.

[0029] In this invention, the molar content of mm in the polypropylene is greater than or equal to 91.6%, for example, it can be 91.6%, 91.7%, 91.8%, 91.9%, 92%, 92.1%, 92.2%, 92.3%, 92.4%, 92.5%, 92.6%, 92.7%, 92.8%, 92.9%, 93%, 93.1%, 93.2%, 93.3%, 93.4%, 93.5%, 93.6%, 93.7%, 93.8%, 93.9%, 94%, 94.1%, 94.2%, 94.3%. %, 94.4%, 94.5%, 94.6%, 94.7%, 94.8%, 94.9%, 95%, 95.1%, 95.2%, 95.3%, 95.4%, 95.5%, 95.6%, 95.7%, 95.8%, 95.9%, 96%, 96.1%, 96.2%, 96.3%, 96.4%, 96.5%, 96.6%, 96.7%, 96.8%, 96.9%, 97%, 97.1%, 97.2%, 97.3%, 97.4%, and the range of any two values.

[0030] In this invention, the molar ratio of mmmm to mm is greater than or equal to 95.85%, for example, it can be 95.85%, 95.86%, 95.87%, 95.88%, 95.89%, 95.9%, 95.91%, 95.92%, 95.93%, 95.94%, 95.95%, 95.96%, 95.97%, 95.98%, 95.99%, 96%, 96.01%, 96.02%, 96.03%, 96.04%, 96.05%, 96.06%, 96.07%, 96.08%, 96.1%, 96.11%, 96.12%, 96.13%, 96.14%, 96.15%. %, 96.16%, 96.17%, 96.18%, 96.19%, 96.2%, 96.21%, 96.22%, 96.23%, 96.24%, 96.25%, 96.26%, 96.27%, 96.28%, 96.29%, 96.3%, 96.31%, 96.32%, 96.33%, 96.34%, 96.35%, 96.36%, 96.37%, 96.38%, 96.39%, 96.4%, 96.41%, 96.42%, 96.43%, 96.44%, 96.45%, 96.46%, 96.47%, 96.48%, 96.49%, 96.5%, 96.51%. 96.52%, 96.53%, 96.54%, 96.55%, 96.56%, 96.57%, 96.58%, 96.59%, 96.6%, 96.01%, 96.02%, 96.03%, 96.04%, 96.05%, 96.06%, 96.07%, 96.08%, 96.09%, 96.1%, 96.11%, 96.12%, 96.13%, 96.14%, 96.15%, 96.16%, 96.17%, 96.18%, 96.19%, 96.2%, 96.21%, 96.22%, 96.23%, 96.24%, 96.25%, 96.26%, 96.27%, 9 6.28%, 96.29%, 96.3%, 96.31%, 96.32%, 96.33%, 96.34%, 96.35%, 96.36%, 96.37%, 96.38%, 96.39%, 96.4%, 96.41%, 96.42%, 96.43%, 96.44%, 96.45%, 96.46%, 96.47%, 96.48%, 96.49%, 96.5%, 96.51%, 96.52%, 96.53%, 96.54%, 96.55%, 96.56%, 96.57%, 96.58%, 96.59%, 96.6%, 96.61%, 96.62%, 96.63%, 96.64%, 96.65%, 96.66%, 96.67%, 96.68%, 96.69%, 96.7%, 96.71%, 96.72%, 96.73%, 96.74%, 96.75%, 96.76%, 96.77%, 96.78%, 96.79%, 96.8%, 96.81%, 96.82%, 96.83%, 96.84%, 96.85%, 96.86%, 96.87%, 96.88%, 96.89%, 96.9%, 96.91%, 96.92%, 96.93%, 96.94%, 96.95%, 9 6.96%, 96.97%, 96.98%, 96.99%, 97%, 97.01%, 97.02%, 97.03%, 97.04%, 97.05%, 97.06%, 97.07%, 97.08%, 97.09%, 97.1%, 97.12%, 97.13%, 97.14%, 97.15%, 97.16%, 97.17%, 97.18%, 97.19%, 97.2%, 97.22%, 97.23%, 97.24%, 97.25%, 97.26%, 97.27%, 97.28%, 97.29%, 97 0.3%, 97.31%, 97.32%, 97.33%, 97.34%, 97.35%, 97.36%, 97.37%, 97.38%, 97.39%, 97.4%, 97.41%, 97.42%, 97.43%, 97.44%, 97.45%, 97.46%, 97.47%, 97.48%, 97.49%, 97.5%, 97.52%, 97.54%, 97.56%, 97.58%, 97.6%, 97.62%, 97.64%, 97.66%, 97.68%, 97.7%, 97.72%, 97. 74%, 97.76%, 97.78%, 97.8%, 97.82%, 97.84%, 97.86%, 97.88%, 97.9%, 97.92%, 97.94%, 97.96%, 97.98%, 98%, 98.1%, 98.2%, 98.3%, 98.4%, 98.5%, 98.6%, 98.7%, 98.8%, 98.9%, 99%, 99.1%, 99.2%, 99.3%, 99.4%, 99.5%, 99.6%, 99.7%, 99.8%, 99.9%, 100%, and any range of two values.

[0031] In this invention, the full width at half maximum (FWHM) of the melting peak of the polypropylene is greater than or equal to 6°C. For example, it can be greater than or equal to 6°C, greater than or equal to 6.1°C, greater than or equal to 6.2°C, greater than or equal to 6.3°C, greater than or equal to 6.4°C, greater than or equal to 6.5°C, greater than or equal to 6.6°C, greater than or equal to 6.7°C, greater than or equal to 6.8°C, greater than or equal to 6.9°C, greater than or equal to 7°C, greater than or equal to 7.1°C, greater than or equal to 7.2°C, greater than or equal to 7.3°C, greater than or equal to 7.4°C, greater than or equal to 7.5°C, greater than or equal to 7.6°C, greater than or equal to 7.7°C, greater than or equal to 7.8°C, greater than or equal to 7.9°C, greater than or equal to 8°C, greater than or equal to 8.1°C, or greater than or equal to 8.2°C. The ranges are as follows: ≥8.3℃, ≥8.4℃, ≥8.5℃, ≥8.6℃, ≥8.7℃, ≥8.8℃, ≥8.9℃, ≥9℃, ≥9.1℃, ≥9.1℃, ≥9.2℃, ≥9.3℃, ≥9.4℃, ≥9.5℃, ≥9.6℃, ≥9.7℃, ≥9.8℃, ≥9.9℃, ≥10℃, ≥10.2℃, ≥10.4℃, ≥10.6℃, ≥10.8℃, ≥11℃, etc., and any range of any two values.

[0032] Preferably, the polypropylene has a molar content of mm less than or equal to 97.1%, a molar content of mmmm of 92-95.5%, a molar ratio of the molar content of mmmm to the molar content of mm of 96% or more, and a half-peak width of the melting peak of the polypropylene greater than or equal to 6.5°C.

[0033] More preferably, the polypropylene has a molar content of mm less than or equal to 97.1%, a molar content of mmmm of mm is 92.3-95%, a molar ratio of the molar content of mmmm to the molar content of mm is greater than or equal to 96.1%, and the polypropylene has a half-peak width of 6.5-10°C.

[0034] To further improve the nominal strain at tensile break of polypropylene, preferably, the enthalpy of melting of the polypropylene is less than or equal to 10⁸ J / g, for example, it can be less than or equal to 10⁸ J / g, less than or equal to 10⁷ J / g, less than or equal to 10⁶ J / g, less than or equal to 10⁵ J / g, less than or equal to 10⁴ J / g, less than or equal to 10⁃ J / g, less than or equal to 10⁂ J / g, less than or equal to 10⁶ J / g, less than or equal to 10⁰ J / g, less than or equal to 9⁹ J / g, less than or equal to 9⁸ J / g, less than or equal to 9⁷ J / g, less than or equal to 9⁶ J / g. The values ​​are less than or equal to 95 J / g, less than or equal to 94 J / g, less than or equal to 93 J / g, less than or equal to 92 J / g, less than or equal to 91 J / g, less than or equal to 90 J / g, less than or equal to 89 J / g, less than or equal to 88 J / g, less than or equal to 87 J / g, less than or equal to 86 J / g, less than or equal to 85 J / g, less than or equal to 84 J / g, less than or equal to 83 J / g, less than or equal to 82 J / g, less than or equal to 81 J / g, less than or equal to 80 J / g, etc., preferably less than or equal to 105 J / g, and any range of two values.

[0035] To further improve the nominal tensile strain at break of polypropylene, and simultaneously improve or maintain the tensile stress at break of polypropylene, preferably, the intrinsic viscosity of the polypropylene at 160°C is 1.3-1.9 dL / g, more preferably 1.35-1.85 dL / g, and even more preferably 1.4-1.85 dL / g. For example, it can be 1.3 dL / g, 1.31 dL / g, 1.32 dL / g, 1.33 dL / g, 1.34 dL / g, 1.35 dL / g, etc. .36dL / g, 1.37dL / g, 1.38dL / g, 1.39dL / g, 1.4dL / g, 1.41dL / g, 1.42dL / g, 1.43dL / g, 1.44dL / g, 1.45 dL / g, 1.46dL / g, 1.47dL / g, 1.48dL / g, 1.49dL / g, 1.5dL / g, 1.51dL / g, 1.52dL / g, 1.53dL / g, 1.54dL / g , 1.55dL / g, 1.56dL / g, 1.57dL / g, 1.58dL / g, 1.59dL / g, 1.6dL / g, 1.61dL / g, 1.62dL / g, 1.63dL / g, 1. 64dL / g, 1.65dL / g, 1.66dL / g, 1.67dL / g, 1.68dL / g, 1.69dL / g, 1.7dL / g, 1.71dL / g, 1.72dL / g, 1.73dL / g, 1.74dL / g, 1.75dL / g, 1.76dL / g, 1.77dL / g, 1.78dL / g, 1.79dL / g, 1.8dL / g, 1.81dL / g, 1.82dL / g, 1.83dL / g, 1.84dL / g, 1.85dL / g, 1.86dL / g, 1.87dL / g, 1.88dL / g, 1.89dL / g, 1.9dL / g, and any range of two values.

[0036] In one specific embodiment of the present invention, the intrinsic viscosity can be measured using a CRYSTEX-QC instrument from Polymer Char GmbH, Spain, at 160°C. Specifically, trichlorobenzene is used as the solvent, the sample is prepared to a concentration of 10 mg / mL, and the test is performed at 160°C.

[0037] To further improve the nominal tensile strain at break of polypropylene, and at the same time further improve or maintain the tensile stress at break of polypropylene, the molecular weight distribution of polypropylene is 3-7, preferably 3-6, for example, it can be 3.1, 3.2, 3.3, 3.4, 3.5, 3.6, 3.8, 3.9, 4, 4.1, 4.2, 4.3, 4.4, 4.5, 4.6, 4.7, 4.8, 4.9, 5, 5.1, 5.2, 5.3, 5.4, 5.5, 5.6, 5.7, 5.8, 5.9, 6, 6.1, 6.2, 6.3, 6.4, 6.5, 6.6, 6.7, 6.8, 6.9, 7, and any range of two values.

[0038] In one specific embodiment of the present invention, the molecular weight distribution (Mw / Mn) of polypropylene can be measured using a PL-GPC220 gel chromatography system with a Polymer Laboratory MIXED-B column, 1,2,4-trichlorobenzene as solvent, an operating temperature of 150°C, and polystyrene as the calibrator.

[0039] According to the present invention, preferably, the melt index of the polypropylene at 230°C and 2.16 kg is 8.5-45 g / 10 min, more preferably 9-30 g / 10 min, and even more preferably 10-30 g / 10 min. For example, it can be 8.5 g / 10 min, 9 g / 10 min, 9.5 g / 10 min, 10 g / 10 min, 10.5 g / 10 min, 11 g / 10 min, 11.5 g / 10 min, 12 g / 10 min, 12.5 g / 10 min, 13 g / 10 min, 13.5 g / 10 min, 14 g / 10 min, or 14.5 g / 10 min. , 15g / 10min, 15.5g / 10min, 16g / 10min, 16.5g / 10min, 17g / 10min, 17.5g / 10min, 18g / 10min, 18.5g / 10min, 19g / 10min, 19.5g / 10min, 20g / 10min, 20.5g / 10min, 21g / 10min, 21.5g / 10min, 22g / 10min, 22.5g / 10min, 23g / 10min, 23.5g / 10min, 24g / 10min, 24.5g / 10min, 25g / 10m in, 25.5g / 10min, 26g / 10min, 26.5g / 10min, 27g / 10min, 27.5g / 10min, 28g / 10min, 28.5g / 10min, 29g / 10min, 29.5g / 10min, 30g / 10min, 3 0.5g / 10min, 31g / 10min, 31.5g / 10min, 32g / 10min, 32.5g / 10min, 33g / 10min, 33.5g / 10min, 34g / 10min, 34.5g / 10min, 35g / 10min, 35.5g / 10min, 36g / 10min, 36.5g / 10min, 37g / 10min, 37.5g / 10min, 38g / 10min, 38.5g / 10min, 39g / 10min, 39.5g / 10min, 40g / 10min, 40.5g / 10min, 41g / 10min, 41.5g / 10min, 42g / 10min, 42.5g / 10min, 43g / 10min, 43.5g / 10min, 44g / 10min, 44.5g / 10min, 45g / 10min, and any range of two values.

[0040] In this invention, when the melt index is within the above range, the polypropylene can be processed at a relatively low temperature when preparing fibers or fiber products. While ensuring processing, this effectively reduces the degradation damage to the resin caused by high-temperature processing, ensuring that the resulting fibers or fiber products have high nominal tensile strain at break and high tensile stress at break, and effectively reducing production energy consumption.

[0041] In one specific embodiment of the present invention, the melt index of polypropylene is determined according to ASTM D1238-99, the test load is 2.16 kg, the test temperature is 230°C, and the specific test method is selected according to the specific design conditions of the melt indexer. The melt index test of polypropylene in the present invention is carried out using method B.

[0042] A second aspect of the present invention provides a method for preparing polypropylene, wherein the method comprises the following steps: polymerizing a propylene-containing material in the presence of hydrogen and a catalyst system; wherein,

[0043] The catalyst system comprises: a titanium-containing catalyst, alkyl aluminum, and an optional external electron donor; wherein the titanium-containing catalyst is prepared from a mixture of components A, B, C, magnesium halides and / or magnesium halide adducts, and titanium-containing compounds.

[0044] The preparation method of the titanium-containing catalyst includes:

[0045] Step (1): Optionally, prepare magnesium halide adducts;

[0046] Step (2): Mix component A, component B, component C, magnesium halide and / or the magnesium halide adduct and titanium-containing compound;

[0047] Component A is selected from at least one of hydroxybenzoyl compounds, component B is selected from at least one of alkoxybenzoyl compounds, and component C is selected from at least one of ester compounds and / or ether compounds, wherein component C is different from components A and components B.

[0048] In this invention, when preparing polypropylene, the polymerization reaction can be homopolymerization or copolymerization, and the comonomer can be ethylene and / or butene. In a preferred case, the weight ratio of structural units from ethylene and / or butene to propylene is (0.1-7):(93-99.9), for example, it can be 0.1:99.9, 0.5:99.5, 1:99, 1.5:98.5, 2:98, 2.5:97.5, 3:97, 3.5:96.5, 4:96, 5:95, 6:94, 7:93, and any range of two values.

[0049] The present invention does not particularly limit the conditions of the polymerization reaction, and can use conventional conditions in the art. Preferably, the temperature of the polymerization reaction is 60-80°C, for example, 60°C, 65°C, 70°C, 75°C, 80°C, or any range of two values. The time of the polymerization reaction (catalyst residence time) is 0.5-3h, for example, 0.5h, 1h, 1.5h, 2h, 2.5h, 3h, or any range of two values.

[0050] According to the present invention, preferably, during the polymerization reaction, the amount of hydrogen used is such that the concentration of hydrogen in the propylene-containing material is 300-4500 ppm, more preferably 300-3500 ppm, for example, 300 ppm, 400 ppm, 500 ppm, 600 ppm, 700 ppm, 800 ppm, 900 ppm, 1000 ppm, 1200 ppm, 1400 ppm, 1600 ppm, 1800 ppm, 2000 ppm, 22 00ppm, 2400ppm, 2600ppm, 2800ppm, 3000ppm, 3100ppm, 3200ppm, 3300ppm, 3400ppm, 3500ppm, 3600ppm, 3700ppm, 3800ppm, 3900ppm, 4000ppm, 4100ppm, 4200ppm, 4300ppm, 4400ppm, 4500ppm, and any range of two values.

[0051] According to the present invention, polypropylene obtained through polymerization can be directly granulated and further processed. The melt index of the polypropylene obtained in this way is the result of the action of hydrogen gas, a molecular weight regulator, during the polymerization stage. The melt index of the polypropylene can be further adjusted by using a degradation agent to achieve 8.5-45 g / 10 min, preferably 9-30 g / 10 min, and more preferably 10-30 g / 10 min. The degradation agent can be any commonly used degradation agent in the art, and can be solid or liquid, and can also be added in the form of masterbatch.

[0052] According to the present invention, in order to further eliminate the influence of impurities in the system on the polymerization reaction and maintain good polymer properties, preferably, the molar ratio of alkylaluminum to propylene in the catalyst system is 1:(7500-55000), more preferably 1:(11000-34000), for example, 1:7500, 1:8000, 1:9000, 1:10000, 1:11000, 1:12000, 1:13000. 1:14000, 1:15000, 1:16000, 1:18000, 1:20000, 1:22000, 1:24000, 1:26000, 1:28000, 1:30000, 1:32000, 1:34000, 1:36000, 1:38000, 1:40000, 1:45000, 1:50000, 1:55000, and any range of two values.

[0053] According to the present invention, preferably, in the mixture, the amount of magnesium halide and / or magnesium halide adduct, calculated based on elemental magnesium, is such that the molar ratio of component A, component B, component C, magnesium halide and / or magnesium halide adduct, and titanium-containing compound is (0.005-0.4):(0.005-0.4):(0.01-0.5):1:(5-100), preferably (0.01-0.25):(0.01-0.25):(0.05-0.35):1:(15-90), more preferably (0.02-0.18):(0.02-0.18):(0.05-0.25):1:(25-80), for example, 0.005:0.005:0.01:1:5, 0. 01:0.005:0.01:1:5, 0.02:0.005:0.01:1:5, 0.03:0.005:0.01:1:5, 0.04:0.005:0.01:1:5, 0.05:0.005:0.01:1:5, 0.06:0.005:0.01:1:5, 0.08:0. 005:0.01:1:5, 0.1:0.005:0.01:1:5, 0.2:0.005:0.01:1:5, 0.3:0.005:0.01:1:5, 0.4:0.005:0.01:1:5, 0.005:0.01:0.01:1:5, 0.01:0.02:0.01:1 :5, 0.02:0.04:0.01:1:5, 0.03:0.06:0.01:1:5, 0.04:0.08:0.01:1:5, 0.05:0.1:0.01:1:5, 0.06:0.2:0.01:1:5, 0.08:0.3:0.01:1:5, 0.1:0.4:0.0 1:1:5, 0.005:0.005:0.02:1:5, 0.01:0.005:0.04:1:5, 0.02:0.005:0.06:1:5, 0.03:0.005:0.08:1:5, 0.04:0.005:0.1:1:5, 0.05:0.005:0.15:1:5 , 0.06:0.005:0.2:1:5, 0.08:0.005:0.25:1:5, 0.1:0.005:0.3:1:5, 0.2:0.005:0.35:1:5, 0.005:0.005:0.02:1:10, 0.01:0.005:0.04:1:20, 0.02: 0.005:0.06:1:30, 0.03:0.005:0.08:1:35, 0.04:0.005:0.1:1:40, 0.05:0.005:0.15:1:45, 0.06:0.005:0.2:1:50, 0.08:0.005:0.25:1:55, 0.1:0.The given ranges are: 005:0.3:1:60, 0.2:0.005:0.35:1:65, 0.2:0.005:0.35:1:70, 1:65, 0.2:0.005:0.35:1:75, 1:65, 0.2:0.005:0.35:1:80, 1:65, 0.2:0.005:0.35:1:85, 1:65, 0.2:0.005:0.35:1:90, 1:65, 0.2:0.005:0.35:1:95, 1:65, 0.2:0.005:0.35:1:100, and any range of any two values.

[0054] According to the present invention, preferably, in the catalyst system, the amount of titanium-containing catalyst is calculated based on titanium element, the amount of alkyl aluminum is calculated based on aluminum element, and the molar ratio of titanium-containing catalyst to alkyl aluminum is 1:(1-2000), more preferably 1:(20-700), for example, it can be 1:1, 1:10, 1:20, 1:40, 1:60, 1:80, 1:100, 1:200, 1:300, 1:400, 1:500, 1:600, 1:700, 1:800, 1:900, 1:1000, 1:1200, 1:1400, 1:1600, 1:1800, 1:2000, and any range of two values.

[0055] According to the present invention, preferably, in the catalyst system, the amount of alkylaluminum is calculated as aluminum, and the amount of external electron donor is such that, relative to 1 mol of alkylaluminum, the amount of external electron donor is 0.005-0.5 mol, more preferably 0.01-0.4 mol, for example, 0.005 mol, 0.01 mol, 0.02 mol, 0.03 mol, 0.04 mol, 0.05 mol, 0.06 mol, 0.07 mol, 0.08 mol, 0.09 mol, 0.1 mol, 0.2 mol, 0.3 mol, 0.4 mol, 0.5 mol, and any range of two values. According to the present invention, the alkylaluminum can be any alkylaluminum commonly used in the field of olefin polymerization that can be used as a co-catalyst for Ziegler-Natta type catalysts.

[0056] Specifically, the alkylaluminum may include, but is not limited to, at least one of trimethylaluminum, triethylaluminum, triisobutylaluminum, trioctylaluminum, diethylaluminum hydrogen, diisobutylaluminum hydrogen, diethylaluminum chloride, diisobutylaluminum chloride, sesquiethylaluminum chloride, and diethylaluminum chloride.

[0057] According to the present invention, the external electron donor can be any of the external electron donors commonly used in the field of olefin polymerization that can be used as an adjuvant for Ziegler-Natta type catalysts.

[0058] Specifically, the external electron donor may include, but is not limited to, trimethylmethoxysilane, trimethylethoxysilane, trimethylphenoxytriethylmethoxysilane, triethylethoxysilane, dimethyldimethoxysilane, dimethyldiethoxysilane, ethylisopropyldimethoxysilane, propylisopropyldimethoxysilane, diisopropyldimethoxysilane, diisobutyldimethoxysilane, isopropylisobutyldimethoxysilane, di-tert-butyldimethoxysilane, tert-butylmethyldimethoxysilane, tert-butylethyldimethoxysilane, tert-butylpropyldimethoxysilane, tert-butylisopropyldimethoxysilane, tert-butyl ... Cyclohexyl dimethoxysilane, tert-butyl isobutyl dimethoxysilane, tert-butyl (sec-butyl) dimethoxysilane, tert-butyl pentyl dimethoxysilane, tert-butyl nonyl dimethoxysilane, tert-butyl hexyl dimethoxysilane, tert-butyl heptyl dimethoxysilane, tert-butyl octyl dimethoxysilane, tert-butyl decyl dimethoxysilane, methyl tert-butyl dimethoxysilane, cyclohexyl methyl dimethoxysilane, cyclohexyl ethyl dimethoxysilane, cyclohexyl propyl dimethoxysilane, cyclohexyl isobutyl dimethoxysilane, dicyclohexyl dimethoxysilane, cyclohexyl tert-butyl dimethoxysilane, cyclopentyl methyl dimethoxysilane Cyclopentylethyl dimethoxysilane, cyclopentylpropyl dimethoxysilane, cyclopentyl tert-butyl dimethoxysilane, dicyclopentyl dimethoxysilane, cyclopentylcyclohexyl dimethoxysilane, bis(2-methylcyclopentyl)dimethoxysilane, diphenyl dimethoxysilane, diphenyl diethoxysilane, phenyl triethoxysilane, methyl trimethoxysilane, methyl triethoxysilane, ethyl trimethoxysilane, ethyl triethoxysilane, propyl trimethoxysilane, isopropyl trimethoxysilane, butyl trimethoxysilane, butyl triethoxysilane, isobutyl trimethoxysilane, tert-butyl trimethoxysilane, sec-butyl trimethoxysilane The silane is at least one of the following: methoxysilane, pentyltrimethoxysilane, isopentyltrimethoxysilane, cyclopentyltrimethoxysilane, cyclohexyltrimethoxysilane, diphenyldimethoxysilane, diphenyldiethoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, n-propyltrimethoxysilane, vinyltrimethoxysilane, tetramethoxysilane, tetraethoxysilane, tetrabutoxysilane, 2-ethylpiperidinyl-2-tert-butyldimethoxysilane, (1,1,1-trifluoro-2-propyl)-2-ethylpiperidinyldimethoxysilane, and (1,1,1-trifluoro-2-propyl)-methyldimethoxysilane. More preferably, the external electron donor may be at least one of dicyclopentyldimethoxysilane, diisopropyldimethoxysilane, diisobutyldimethoxysilane, cyclohexylmethyldimethoxysilane, methyltert-butyldimethoxysilane, and tetramethoxysilane.

[0059] In this invention, the alkylaluminum and optional external electron donor can be reacted with the titanium-containing catalyst alone or as a mixture of the two components.

[0060] In a preferred embodiment of the invention, the titanium-containing catalyst includes, in addition to the three electron-donating compounds (components A, B, and C), titanium, magnesium, and halogens. Preferably, the catalyst is a magnesium halide supported on a magnesium halide containing the titanium compound and the reaction products of components A, B, and C. The magnesium halide is preferably magnesium dihalide in an activated state, more preferably activated magnesium dichloride. Such magnesium dichloride is well known in the art as a support for Ziegler-Natta catalysts. Typically, such activated magnesium dichloride is characterized by a decrease in intensity and expansion into a halo in the X-ray diffraction pattern of inactive magnesium dichloride.

[0061] According to the present invention, activated magnesium dihalides can be prepared using methods known in the art. Generally, inactive magnesium dihalides can be obtained by grinding them in a mill; alternatively, they can be prepared by reacting alkyl magnesium halides, alkyl magnesium halides, alkoxy magnesium halides, or inactive magnesium dihalides with halides (such as aluminum halides, halosilanes, or titanium halides) in a solvent system. Alternatively, inactive magnesium dihalides can be reacted with one or more electron-donating compounds such as esters, alcohols, and ethers to form magnesium halide adducts, which selectively contain trace amounts of water, followed by chemical reaction or heating under negative pressure to remove the coordinated electron donor, thus obtaining activated magnesium dihalides. Depending on the method used to prepare the activated magnesium dihalides, compared to the preparation of olefin polymerization catalysts (including titanium catalysts), the activated magnesium dihalides can be prepared in advance or obtained simultaneously during the preparation of the olefin polymerization catalyst.

[0062] According to the present invention, preferably, the titanium-containing compound is titanium trihalide and Ti(OR′). 4－m X′ m At least one of the titanium compounds shown, where R′ is C1-C 10 The alkyl group, X′ is a halogen, and m is an integer from 0 to 4. Preferably, the titanium-containing compound is one or more of titanium tetrachloride, titanium tetrabromide, titanium tetraiodide, titanium tetrabutoxy, titanium tetraethoxy, titanium monochlorotributoxy, titanium dichlorodibutoxy, titanium trichlorobutoxy, titanium monochlorotriethoxy, titanium dichlorodiethoxy, titanium trichloroethoxy, and titanium trichloride. More preferably, the titanium-containing compound is titanium tetrachloride.

[0063] The olefin polymerization catalyst of this invention can be prepared according to various known methods. For example, the method for preparing solid catalyst components described in CN1006071B can be used. First, inactive magnesium halide is dissolved in a solvent system to form a solution. Then, a titanium-containing compound and components A, B, and C are added. In the presence of a precipitation aid, the olefin polymerization catalyst containing active centers is re-precipitated by heating. Activated magnesium halide is simultaneously generated in the above reaction.

[0064] Alternatively, a magnesium halide adduct can be prepared first, preferably a magnesium halide adduct with the general formula MgX. 1 X 2 The adduct is shown as ·m(R″OH)·nE·qH2O, and the adduct particles are spherical, where m is 1.0-5.0, n is 0-1.0, and q is 0-0.8; X 1 and X 2 Each component is either chlorine or bromine; R″ is a C1-C4 alkyl group; E is an electron-donating compound, which may be an ether or an ester. Preferably, m is 1.5-3.5 and n is 0-0.5. The magnesium halide adduct particles are then reacted with a titanium-containing compound, component A, component B, and component C to finally obtain a catalyst component for olefin polymerization containing activated magnesium halide. Methods for preparing this olefin polymerization catalyst are disclosed in CN1036011C, CN1151183C, CN101565475A, and CN101486776B.

[0065] In this invention, the magnesium halide adduct is a complex with obvious XRD crystal characteristics formed by the coordination reaction of a compound with electron donor characteristics and magnesium halide in the liquid state. The titanium-containing catalyst is a complex with new chemical bonds formed on the crystal structure of the above-mentioned magnesium halide and / or magnesium halide adduct after chemical reaction of components A, B, C and titanium-containing compounds with magnesium halides and / or magnesium halide adducts.

[0066] In any preparation method, components A, B, and C may be added before, during, or after the reaction of magnesium halide or magnesium halide adduct with the titanium-containing compound; preferably, they may be added during the reaction with the titanium-containing compound. According to the present invention, components A, B, and C may also be added simultaneously or in stages, and each component A, B, and C may be added in multiple steps, with no particular order of addition.

[0067] In a preferred embodiment of the present invention, the catalyst system comprises a titanium-containing catalyst, alkyl aluminum, and an optional external electron donor; wherein the titanium-containing catalyst is prepared from a mixture comprising component A, component B, component C, a magnesium halide adduct, and a titanium-containing compound; wherein component A is selected from at least one of hydroxybenzoyl compounds, component B is selected from at least one of alkoxybenzoyl compounds, and component C is selected from at least one of ester compounds and / or ether compounds, wherein component C is different from components A and B; the magnesium halide adduct has the general formula shown in formula (1);

[0068] MgX 1 X 2·m(R″OH)·nE·qH2O (1), where m is 1-5, n is 0-1, and q is 0-0.8; X 1 and X 2 Each is either chlorine or bromine; R″ is a C1-C4 alkyl group; E is an electron-donating compound.

[0069] In a preferred embodiment of the present invention, the method for preparing the titanium-containing catalyst includes:

[0070] S1. In the presence of a solvent, at low temperature, the titanium-containing compound and the magnesium halide adduct are mixed for the first time;

[0071] S2. The product from step S1 is heated to a higher temperature, and components A, B and C are added during the heating process.

[0072] After the product of step S2 undergoes the first reaction, the liquid is filtered out, a titanium-containing compound is added, and the second reaction is continued. The liquid is then filtered out again, and the titanium-containing compound is added again to continue the third reaction. After filtering out the liquid, the product is washed and dried to obtain the titanium-containing catalyst.

[0073] In this invention, the low temperature condition is -40 to 5°C, and the first mixing time is 5-60 minutes.

[0074] In this invention, the temperature is raised to 80-130℃.

[0075] In this invention, the conditions for the first reaction, the second reaction, and the third reaction each independently include: a reaction temperature of 80-130℃ and a reaction time of 10-50 min.

[0076] In this invention, there is no particular limitation on the amount of titanium-containing compound added in each step, which can be adjusted according to actual needs. For example, based on titanium, the molar ratio of titanium-containing compound in step S1, titanium-containing compound added after the first reaction, and titanium-containing compound added after the second reaction is 1:0.6-1.2:0.6-1.2.

[0077] According to the present invention, preferably, the hydroxybenzoyl compound is selected from the compounds shown in formula (I).

[0078] in,

[0079] R1 is hydrogen, C1-C 20 Straight-chain or branched alkyl groups, C3-C 20 Substituted or unsubstituted cycloalkyl, C6-C 20 Substituted or unsubstituted aryl groups and C7-C 20One of the substituted or unsubstituted aralkyl groups; R2, R3, R4 and R5 are each independently hydrogen, halogen, nitro, C1-C 20 Straight-chain or branched alkyl groups, C3-C 20 Substituted or unsubstituted cycloalkyl, C6-C 20 Substituted or unsubstituted aryl groups and C7-C 20 One of the substituted or unsubstituted aralkyl groups; two or more of R2, R3, R4 and R5 can be bonded to each other to form a ring.

[0080] According to the present invention, preferably, R1 is hydrogen, a C1-C6 straight-chain or branched alkyl group, a C3-C6 substituted or unsubstituted cycloalkyl group, or a C6-C6 substituted or unsubstituted cycloalkyl group. 10 Substituted or unsubstituted aryl groups and C7-C 10 One of the substituted or unsubstituted aralkyl groups, wherein R2, R3, R4, and R5 are each independently hydrogen, C1-C8 straight-chain or branched alkyl, C3-C6 substituted or unsubstituted cycloalkyl, C6-C 10 Substituted or unsubstituted aryl groups and C7-C 10 One of the substituted or unsubstituted aralkyl groups.

[0081] According to the present invention, preferably, R1 is methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, n-pentyl, n-hexyl, benzyl or phenethyl, and R2, R3, R4 and R5 are each independently hydrogen, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, n-pentyl, isopentyl, cyclopentyl, n-hexyl, n-heptyl or tolyl.

[0082] According to the present invention, preferably, the hydroxybenzoyl compound is selected from at least one of 4-hydroxybenzoic acid compounds, 4-hydroxybenzoic acid ester compounds, 2-hydroxybenzoic acid compounds, and 2-hydroxybenzoic acid ester compounds; more preferably, it is selected from 2-hydroxybenzoic acid compounds and / or 2-hydroxybenzoic acid ester compounds.

[0083] According to a preferred embodiment of the present invention, the hydroxybenzoyl compound is selected from 2-hydroxybenzoic acid ester compounds.

[0084] According to the present invention, 2-hydroxybenzoic acid ester compounds may include, but are not limited to: methyl 2-hydroxybenzoate, ethyl 2-hydroxybenzoate, n-propyl 2-hydroxybenzoate, isopropyl 2-hydroxybenzoate, n-butyl 2-hydroxybenzoate, isobutyl 2-hydroxybenzoate, n-pentyl 2-hydroxybenzoate, n-hexyl 2-hydroxybenzoate, methyl 2-hydroxy-3-methylbenzoate, methyl 2-hydroxy-4-methylbenzoate, methyl 2-hydroxy-5-methylbenzoate, methyl 2-hydroxy-3-ethylbenzoate, methyl 2-hydroxy-4-ethylbenzoate, etc. Methyl benzoate, 2-hydroxy-5-ethylbenzoate, ethyl 2-hydroxy-3-methylbenzoate, ethyl 2-hydroxy-4-methylbenzoate, ethyl 2-hydroxy-5-methylbenzoate, ethyl 2-hydroxy-3-ethylbenzoate, ethyl 2-hydroxy-4-ethylbenzoate, ethyl 2-hydroxy-5-ethylbenzoate, n-propyl 2-hydroxy-3-methylbenzoate, n-propyl 2-hydroxy-4-methylbenzoate, n-propyl 2-hydroxy-5-methylbenzoate, n-propyl 2-hydroxy-3-ethylbenzoate, n-propyl 2-hydroxy- 4-Ethylbenzoate n-propyl ester, 2-Hydroxy-5-Ethylbenzoate n-propyl ester, 2-Hydroxy-3-Methylbenzoate isopropyl ester, 2-Hydroxy-4-Methylbenzoate isopropyl ester, 2-Hydroxy-5-Methylbenzoate isopropyl ester, 2-Hydroxy-3-Ethylbenzoate isopropyl ester, 2-Hydroxy-4-Ethylbenzoate isopropyl ester, 2-Hydroxy-5-Ethylbenzoate isopropyl ester, 2-Hydroxy-3-Methylbenzoate isobutyl ester, 2-Hydroxy-4-Methylbenzoate isobutyl ester, 2-Hydroxy-5-Methylbenzoate isobutyl ester, 2-Hydroxy-3-Ethylbenzoate Isobutyl formate, 2-hydroxy-4-ethylbenzoate, 2-hydroxy-5-ethylbenzoate, ethyl 2-hydroxy-3-n-propylbenzoate, ethyl 2-hydroxy-4-n-propylbenzoate, ethyl 2-hydroxy-5-n-propylbenzoate, ethyl 2-hydroxy-4-isopropylbenzoate, ethyl 2-hydroxy-4-isobutylbenzoate, ethyl 2-hydroxy-4-tert-butylbenzoate, ethyl 2-hydroxy-4-n-pentylbenzoate, ethyl 2-hydroxy-4-isopentylbenzoate, and ethyl 2-hydroxy-4-cyclopentylbenzoate.

[0085] In a preferred embodiment of the present invention, the hydroxybenzoyl compound is ethyl 2-hydroxybenzoate.

[0086] According to the present invention, preferably, the alkoxybenzoyl compound is selected from the compounds shown in formula (II).

[0087] in,

[0088] R6 is hydrogen, C1-C 20 Straight-chain or branched alkyl groups, C3-C 20 Substituted or unsubstituted cycloalkyl, C6-C 20Substituted or unsubstituted aryl groups and C7-C 20 One of the substituted or unsubstituted aralkyl groups; R7 is C1-C 20 Straight-chain or branched alkyl groups, C3-C 20 Substituted or unsubstituted cycloalkyl, C6-C 20 Substituted or unsubstituted aryl groups and C7-C 20 One of the substituted or unsubstituted aralkyl groups; R8, R9, R 10 and R 11 Each is independently hydrogen, halogen, nitro, C1-C 20 Straight-chain or branched alkyl groups, C3-C 20 Substituted or unsubstituted cycloalkyl, C6-C 20 Substituted or unsubstituted aryl groups and C7-C 20 One of the substituted or unsubstituted aralkyl groups; R8, R9, R 10 and R 11 Two or more elements can bond together to form a ring.

[0089] According to the present invention, preferably, R6 and R7 are each independently a C1-C6 straight-chain or branched alkyl group, a C3-C6 substituted or unsubstituted cycloalkyl group, or a C6-C6 substituted cycloalkyl group. 10 Substituted or unsubstituted aryl groups and C7-C 10 One of the substituted or unsubstituted aralkyl groups; R8, R9, R 10 and R 11 Each is independently hydrogen, a C1-C8 straight-chain or branched alkyl group, a C3-C6 substituted or unsubstituted cycloalkyl group, or a C6-C... 10 Substituted or unsubstituted aryl groups and C7-C 10 One of the substituted or unsubstituted aralkyl groups.

[0090] According to the present invention, preferably, R6 and R7 are each independently methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, n-pentyl, n-hexyl, benzyl, or phenethyl; R8, R9, R 10 and R 11 Each of them is independently hydrogen, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, n-pentyl, isopentyl, cyclopentyl, n-hexyl, n-heptyl, or tolyl.

[0091] According to the present invention, preferably, the alkoxybenzoyl compound is selected from at least one of 4-alkoxybenzoic acid compounds, 4-alkoxybenzoic acid ester compounds, 2-alkoxybenzoic acid compounds, and 2-alkoxybenzoic acid ester compounds; more preferably, it is selected from 2-alkoxybenzoic acid compounds and / or 2-alkoxybenzoic acid ester compounds.

[0092] According to a preferred embodiment of the present invention, the alkoxybenzoyl compound is selected from 2-alkoxybenzoic acid ester compounds.

[0093] According to the present invention, 2-alkoxybenzoic acid ester compounds may include, but are not limited to: methyl 2-methoxybenzoate, ethyl 2-methoxybenzoate, n-propyl 2-methoxybenzoate, isopropyl 2-methoxybenzoate, n-butyl 2-methoxybenzoate, isobutyl 2-methoxybenzoate, n-pentyl 2-methoxybenzoate, n-hexyl 2-methoxy-3-methylbenzoate, methyl 2-methoxy-4-methylbenzoate, methyl 2-methoxy-5-methylbenzoate, methyl 2-methoxy-3-ethylbenzoate, methyl 2-methoxy-4-ethylbenzoate, and methyl 2-methoxy-5-ethylbenzoate. Ester, ethyl 2-methoxy-3-methylbenzoate, ethyl 2-methoxy-4-methylbenzoate, ethyl 2-methoxy-5-methylbenzoate, ethyl 2-methoxy-3-ethylbenzoate, ethyl 2-methoxy-4-ethylbenzoate, ethyl 2-methoxy-5-ethylbenzoate, n-propyl 2-methoxy-3-methylbenzoate, n-propyl 2-methoxy-4-methylbenzoate, n-propyl 2-methoxy-5-methylbenzoate, n-propyl 2-methoxy-3-ethylbenzoate, n-propyl 2-methoxy-4-ethylbenzoate, n-propyl 2-methoxy-5-ethylbenzoate, isopropyl 2-methoxy-3-methylbenzoate Isopropyl 2-methoxy-4-methylbenzoate, Isopropyl 2-methoxy-5-methylbenzoate, Isopropyl 2-methoxy-3-ethylbenzoate, Isopropyl 2-methoxy-4-ethylbenzoate, Isopropyl 2-methoxy-5-ethylbenzoate, Isobutyl 2-methoxy-3-methylbenzoate, Isobutyl 2-methoxy-4-methylbenzoate, Isobutyl 2-methoxy-5-methylbenzoate, Isobutyl 2-methoxy-3-ethylbenzoate, Isobutyl 2-methoxy-4-ethylbenzoate, Isobutyl 2-methoxy-5-ethylbenzoate, Ethyl 2-methoxy-3-n-propylbenzoate, 2-methoxy-4-n-propylbenzoate Ethyl benzoate, ethyl 2-methoxy-5-n-propylbenzoate, ethyl 2-methoxy-4-isopropylbenzoate, ethyl 2-methoxy-4-isobutylbenzoate, ethyl 2-methoxy-4-tert-butylbenzoate, ethyl 2-methoxy-4-n-pentylbenzoate, ethyl 2-methoxy-4-isopentylbenzoate, ethyl 2-methoxy-4-cyclopentylbenzoate, methyl 2-ethoxybenzoate, ethyl 2-ethoxybenzoate, propyl 2-ethoxybenzoate, isopropyl 2-ethoxybenzoate, butyl 2-ethoxybenzoate, isobutyl 2-ethoxybenzoate, pentyl 2-ethoxybenzoate, and hexyl 2-ethoxybenzoate.

[0094] In a preferred embodiment of the present invention, the alkoxybenzoyl compound is ethyl 2-methoxybenzoate.

[0095] According to the present invention, the ester compound may be one or more of monoaliphatic carboxylic acid esters, polyaliphatic carboxylic acid esters, monoaromatic carboxylic acid esters, polyaromatic carboxylic acid esters, and diol esters.

[0096] In this invention, the term "monolithic aliphatic carboxylic acid ester" refers to a compound formed by the esterification reaction of a monoaliphatic carboxylic acid and a monohydric alcohol. The term "polyaliphatic carboxylic acid ester" refers to a compound formed by the esterification reaction of a polyaliphatic carboxylic acid and a monohydric alcohol. The term "monolithic aromatic carboxylic acid ester" refers to a compound formed by the esterification reaction of a monoaliphatic aromatic carboxylic acid and a monohydric alcohol.

[0097] In this invention, mono-aliphatic carboxylic acid esters, poly-aliphatic carboxylic acid esters, mono-aromatic carboxylic acid esters, and poly-aromatic carboxylic acid esters may be selected, for example, from: benzoic acid esters, phthalic acid esters, malonic acid esters, succinic acid esters, glutaric acid esters, neopentanoic acid esters, and carbonates; preferably at least one of alkyl benzoate, alkyl phthalate, alkyl malonic acid ester, alkyl succinic acid ester, alkyl glutaric acid ester, neopentanoic acid ester, and alkyl carbonate ester.

[0098] Specifically, in this invention, examples of mono-aliphatic carboxylic acid esters, poly-aliphatic carboxylic acid esters, mono-aromatic carboxylic acid esters, and poly-aromatic carboxylic acid esters may include, but are not limited to: ethyl benzoate, diethyl phthalate, diisobutyl phthalate, di-n-butyl phthalate, diisooctyl phthalate, di-n-octyl phthalate, diethyl malonate, dibutyl malonate, diisobutyl malonate, diethyl 2,3-diisopropylsuccinate, diisobutyl 2,3-diisopropylsuccinate, di-n-butyl 2,3-diisopropylsuccinate, dimethyl 2,2-dimethylsuccinate. Diisobutyl succinate, 2-ethyl-2-methylsuccinate, diethyl 2-ethyl-2-methylsuccinate, diethyl glutarate, di-n-butyl glutarate, diisobutyl glutarate, dimethyl carbonate, diethyl carbonate, diisobutyl carbonate, diethyl adipate, di-n-butyl adipate, diethyl sebacate, di-n-butyl sebacate, diethyl maleate, di-n-butyl maleate, diethyl naphthalene dicarboxylate, di-n-butyl naphthalene dicarboxylate, triethyl trimellitate, tri-n-butyl trimellitate, triethyl biphenyltrioxide, tri-n-butyl biphenyltrioxide, tetraethyl pyromellitic acid, and tetra-n-butyl pyromellitic acid.

[0099] In this invention, the term "diol ester compound" refers to a compound formed by the esterification reaction of a diol with a monocarboxylic acid or a polycarboxylic acid. For example, the diol ester can be a compound represented by formula (III).

[0100] In formula (Ⅲ), R I R II R III R IV R V and R VI Each independently is hydrogen, C1-C 10 Substituted or unsubstituted aliphatic hydrocarbon groups, C6-C 10 Substituted or unsubstituted aryl groups and C7-C 10 One of the substituted or unsubstituted aralkyl groups; R I R II R III R IV R V and R VI Two or more elements can bond together to form a ring; R VII and R VIII Each independently is C1-C 10 Straight-chain or branched alkyl groups, C3-C 20 Substituted or unsubstituted cycloalkyl, C6-C 20 Substituted or unsubstituted aryl groups and C7-C 20 One of the substituted or unsubstituted aryl aliphatic hydrocarbon groups.

[0101] Preferably, R I R II R III R IV R V and R VI Each of the following is independently hydrogen, a C1-C6 straight-chain or branched alkyl group, a C2-C6 straight-chain or branched alkenyl group, a C3-C6 substituted or unsubstituted cycloalkyl group, or a C6-C 10 Substituted or unsubstituted aryl groups and C7-C 10 One of the substituted or unsubstituted aralkyl groups; R I R II R III R IV R V and R VI Two or more elements can bond together to form a ring; R VII and R VIII Each is independently a C1-C6 straight-chain or branched alkyl group, a C3-C6 substituted or unsubstituted cycloalkyl group, or a C6-C6 alkyl group. 10 Substituted or unsubstituted aryl groups, C7-C10 Substituted or unsubstituted aralkyl groups and C7-C 10 One of the substituted or unsubstituted aryl groups.

[0102] More preferably, R I R II R V and R VI At least one of them is hydrogen, and R I R II R V and R VI They are not both hydrogen.

[0103] More preferably, R I and R II At least one of them is hydrogen, and in R I and R II When only one of them is hydrogen, R I and R II The other group is one of methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, phenyl, and halophenyl; R V and R VI At least one of them is hydrogen, and in R V and R VI When only one of them is hydrogen, R V and R VI The other group is one of methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, phenyl, and halophenyl; R III and R IV Each of the following is one of hydrogen, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, allyl, n-pentyl, isopentyl, and n-hexyl, R III and R IV They can bond with each other to form substituted or unsubstituted fluorene groups; R VII and R VIII Each of the following is a single compound: methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, n-pentyl, neopentyl, cyclopentyl, cyclohexyl, phenyl, halophenyl, tolyl, halomethylphenyl, benzyl, phenethyl, and styryl.

[0104] Specifically, the diol ester compound may include, for example, but not limited to:

[0105] 1,3-Propanediol dibenzoate, 2-Methyl-1,3-Propanediol dibenzoate, 2-Ethyl-1,3-Propanediol dibenzoate, 2,2-Dimethyl-1,3-Propanediol dibenzoate, (R)-1-Pheny-1,3-Propanediol dibenzoate, 1,3-Diphenyl-1,3-Propanediol dibenzoate, 1,3-Diphenyl-1,3-Propanediol di-n-propionate, 1,3-Diphenyl-2-Methyl-1,3-Propanediol di-n-propionate, 1,3-Diphenyl-2-Methyl-1,3-Propanediol diacetate, 1,3-Diphenyl-2,2-Dimethyl-1,3-Propanediol dibenzoate, 1,3- Di-tert-butyl-2-ethyl-1,3-propanediol dibenzoate, 1,3-diphenyl-1,3-propanediol diacetate, 1,3-diisopropyl-1,3-propanediol di(4-n-butylbenzoic acid) ester, 1-phenyl-2-amino-1,3-propanediol dibenzoate, 1-phenyl-2-methyl-1,3-butanediol dibenzoate, 1-phenyl-2-methyl-1,3-butanediol dinepentyl ester, 3-n-butyl-2,4-pentanediol dibenzoate, 3,3-dimethyl-2,4-pentanediol dibenzoate, (2S,4S)-(+)-2,4-pentanediol dibenzoate, (2R,4R)-(+)-2,4-pentanediol dibenzoate, 2,4-pentanediol di(p-chlorobenzoic acid) ester 2,4-Pentanediol di(m-chlorobenzoic acid), 2,4-Pentanediol di(p-bromobenzoic acid), 2,4-Pentanediol di(o-bromobenzoic acid), 2,4-Pentanediol di(p-methylbenzoic acid), 2,4-Pentanediol di(p-tert-butylbenzoic acid), 2,4-Pentanediol di(p-n-butylbenzoic acid), 2-Methyl-1,3-Pentanediol di(p-chlorobenzoic acid), 2-Methyl-1,3-Pentanediol di(p-methylbenzoic acid), 2-n-Butyl-1,3-Pentanediol di(p-methylbenzoic acid), 2-Methyl-1,3-Pentanediol di(p-tert-butylbenzoic acid), 2-Methyl-1,3-Pentanediol dinepentyl ester, 2-Methyl-3-cinnamoyloxy-1-n-pentanol benzoate, 2,2-di Methyl-1,3-pentanediol dibenzoate, 2,2-dimethyl-3-cinnamoyloxy-1-n-pentanol benzoate, 2-ethyl-1,3-pentanediol dibenzoate, 2-n-butyl-1,3-pentanediol dibenzoate, 2-allyl-1,3-pentanediol dibenzoate, 2-methyl-1,3-pentanediol dibenzoate, 2-ethyl-1,3-pentanediol dibenzoate, 2-n-propyl-1,3-pentanediol dibenzoate, 2-n-butyl-1,3-pentanediol dibenzoate, 2,2-di-n-propyl-1,3-pentanediol dibenzoate, 1,3-pentanediol di(p-chlorobenzoate), 1,3-pentanediol di(m-chlorobenzoate), 1,3-pentanediol di(p-bromobenzoate), 1,3-Pentanediol di(o-bromobenzoic acid) ester, 1,3-Pentanediol di(p-methylbenzoic acid) ester, 1,3-Pentanediol di(p-tert-butylbenzoic acid) ester, 1,3-Pentanediol di(p-butylbenzoic acid) ester, 3-cinnamoyloxy-1-n-pentanol benzoate, 1,3-Pentanediol dicinnamate, 1,3-Pentanediol di-n-propionate, 2-ethyl-1,3-pentanediol dibenzoate, 2-n-butyl-1,3-pentanediol dibenzoate, 2-allyl-1,3-pentanediol dibenzoate, 2,2,4-trimethyl-1,3-pentanediol diisopropylcarboxylate, 1-trifluoromethyl-3-methyl-2,4-pentanediol dibenzoate, 2,4-pentanediol di-p-fluoromethylbenzoate, 2,4-pentanediol di-p-fluoromethylbenzoate, (2-Furfurylic acid) ester, 2-methyl-6-(1-n-heptene)-2,4-heptanediol dibenzoate, 3-methyl-6-(1-n-heptene)-2,4-heptanediol dibenzoate, 4-methyl-6-(1-n-heptene)-2,4-heptanediol dibenzoate, 5-methyl-6-(1-n-heptene)-2,4-heptanediol dibenzoate, 6-methyl-6-(1-n-heptene)-2,4-heptanediol dibenzoate, 3-ethyl-6-(1-n-heptene)-2,4-heptanediol dibenzoate, 4-ethyl-6-(1-n-heptene)-2,4-heptanediol dibenzoate, 5-ethyl-6-(1-n-heptene)-2,4-heptanediol dibenzoate, 6-ethyl- 6-(1-n-Heptene)yl-2,4-heptanediol dibenzoate, 3-n-propyl-6-(1-n-heptene)yl-2,4-heptanediol dibenzoate, 4-n-propyl-6-(1-n-heptene)yl-2,4-heptanediol dibenzoate, 5-n-propyl-6-(1-n-heptene)yl-2,4-heptanediol dibenzoate, 6-n-propyl-6-(1-n-heptene)yl-2,4-heptanediol dibenzoate, 3-n-butyl-6-(1-n-heptene)yl-2,4-heptanediol dibenzoate, 4-n-butyl-6-(1-n-heptene)yl-2,4-heptanediol dibenzoate, 5-n-butyl-6-(1-n-heptene)yl-2,4-heptanediol dibenzoate, 6-n-butyl-6-(1-n-heptene)yl-2,4-heptanediol dibenzoate, Heptenyl-2,4-heptanediol dibenzoate, 3,5-dimethyl-6-(1-n-heptene)yl-2,4-heptanediol dibenzoate, 3,5-diethyl-6-(1-n-heptene)yl-2,4-heptanediol dibenzoate, 3,5-di-n-propyl-6-(1-n-heptene)yl-2,4-heptanediol dibenzoate, 3,5-di-n-butyl-6-(1-n-heptene)yl-2,4-heptanediol dibenzoate, 3,3-dimethyl-6-(1-n-heptene)yl-2,4-heptanediol dibenzoate, 3,3-diethyl-6-(1-n-heptene)yl-2,4-heptanediol dibenzoate, 3,3-di-n-propyl-6-(1-n-heptene)yl-2,4-heptanediol dibenzoate, 3,3-Di-n-butyl-6-(1-n-heptene)-2,4-heptanediol dibenzoate, 3-ethyl-3,5-heptanediol dibenzoate, 4-ethyl-3,5-heptanediol dibenzoate, 5-ethyl-3,5-heptanediol dibenzoate, 3-n-propyl-3,5-heptanediol dibenzoate, 4-n-propyl-3,5-heptanediol dibenzoate, 3-n-butyl-3,5-heptanediol dibenzoate, 2,3-dimethyl-3,5-heptanediol dibenzoate, 2,4-dimethyl 3,5-Heptanediol dibenzoate, 2,5-dimethyl-3,5-heptanediol dibenzoate, 2,6-dimethyl-3,5-heptanediol dibenzoate, 3,5-dimethyl-3,5-heptanediol dibenzoate, 4,4-dimethyl-3,5-heptanediol dibenzoate, 4,5-dimethyl-3,5-heptanediol dibenzoate, 4,6-dimethyl-3,5-heptanediol dibenzoate, 6,6-dimethyl-3,5-heptanediol dibenzoate, 2-methyl-3-ethyl 3,5-Heptanediol dibenzoate, 2-Methyl-4-ethyl-3,5-heptanediol dibenzoate, 2-Methyl-5-ethyl-3,5-heptanediol dibenzoate, 3-Methyl-3-ethyl-3,5-heptanediol dibenzoate, 3-Methyl-4-ethyl-3,5-heptanediol dibenzoate, 3-Methyl-5-ethyl-3,5-heptanediol dibenzoate, 4-Methyl-3-ethyl-3,5-heptanediol dibenzoate, 4-Methyl-4-ethyl-3,5-heptanediol dibenzoate Benzoate esters, 9,9-bis(benzoyloxymethyl)fluorene, 9,9-bis((m-methoxybenzoyloxy)methyl)fluorene, 9,9-bis((m-chlorobenzoyloxy)methyl)fluorene, 9,9-bis((p-chlorobenzoyloxy)methyl)fluorene, 9,9-bis(cinnamyloxymethyl)fluorene, 9-(benzoyloxymethyl)-9-(propionyloxymethyl)fluorene, 9,9-bis(propionyloxymethyl)fluorene, 9,9-bis(acryloyloxymethyl)fluorene, and 9,9-bis(neopentyloxymethyl)fluorene.

[0106] The aforementioned diol ester compounds are disclosed in CN1213080C, CN1169845C, WO 03 / 068828 and WO 03 / 068723.

[0107] According to the present invention, preferably, the ester compound is selected from polyary aromatic carboxylic acid esters, more preferably from polyary aromatic carboxylic acid alkyl esters, and more preferably from diary aromatic carboxylic acid alkyl esters.

[0108] According to the present invention, preferably, the diaromatic carboxylic acid alkyl ester is a phthalic acid alkyl ester, more preferably a C1-C phthalic acid alkyl ester. 10 Straight-chain alkyl esters, C3-C of phthalic acid 10 Branched alkyl esters and C3-C of phthalic acid 10At least one of the cycloalkyl esters. Further, the ester compound is selected from C1-C6 straight-chain alkyl esters of phthalic acid and / or C3-C6 branched alkyl esters of phthalic acid.

[0109] In a preferred embodiment of the present invention, the ester compound is diisobutyl phthalate.

[0110] According to the present invention, preferably, the ether compound is selected from 1,3-diether compounds of formula (IV).

[0111] in,

[0112] R 1 R 2 R 3 R 4 R 5 and R 6 Each is independently hydrogen, halogen, C1-C 20 Straight-chain or branched alkyl groups, C3-C 20 Substituted or unsubstituted cycloalkyl, C6-C 20 Substituted or unsubstituted aryl groups and C7-C 20 One of the substituted or unsubstituted aralkyl groups; R 1 R 2 R 3 R 4 R 5 and R 6 Two or more elements can bond together to form a ring; R 7 and R 8 Each independently is C1-C 20 Straight-chain or branched alkyl groups, C3-C 20 Substituted or unsubstituted cycloalkyl, C6-C 20 Substituted or unsubstituted aryl groups and C7-C 20 One of the substituted or unsubstituted aralkyl groups.

[0113] According to the present invention, preferably, R 1 R 2 R 5 and R 6 It is hydrogen;

[0114] R 7 and R 8 Each is a C1-C4 straight-chain or branched alkyl group, more preferably a methyl group;

[0115] R 3 It is one of methyl, ethyl, n-propyl, and isopropyl, R 4It is one of ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, isopentyl, 2-ethylhexyl, cyclopentyl, cyclohexyl, methylcyclohexyl, phenyl, and benzyl; or, R 3 For hydrogen, R 4 It is one of ethyl, n-butyl, sec-butyl, tert-butyl, 2-ethylhexyl, cyclohexylethyl, diphenylmethyl, p-chlorophenyl, 1-naphthyl, and 1-decahydronaphthyl; or, R 3 and R 4 The same, and is one of ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, neopentyl, phenyl, benzyl, cyclohexyl, and cyclopentyl; R 3 and R 4 They can bond with each other to form cyclopentadienyl, fluorenyl, or indenyl groups.

[0116] The 1,3-diether compounds mentioned above in this invention are disclosed in CN1015062B and CN1121368C.

[0117] In a preferred embodiment of the present invention, the ether compound is 2-isopropyl-2-isopentyl-1,3-dimethoxypropane.

[0118] According to a preferred embodiment of the present invention, a propylene-containing material is subjected to a polymerization reaction in the presence of hydrogen and a catalyst system; the polypropylene obtained by polymerization can be directly granulated and further processed, or it can be further degraded by a degradation agent to further adjust the melt index of the polypropylene; wherein, the amount of hydrogen used is such that the concentration of hydrogen in the propylene-containing material is 300-4500 ppm, the polymerization reaction temperature is 60-80°C, and the polymerization reaction time (catalyst residence time) is 0.5-3 h;

[0119] The catalyst system comprises: a titanium-containing catalyst, alkyl aluminum, and an optional external electron donor; wherein the titanium-containing catalyst is prepared from a mixture comprising component A, component B, component C, magnesium halides and / or magnesium halide adducts, and titanium-containing compounds; wherein component A is selected from at least one hydroxybenzoyl compound, component B is selected from at least one alkoxybenzoyl compound, and component C is selected from at least one ester compound and / or ether compound, wherein component C is different from components A and B. The magnesium halides and / or magnesium halide adducts are selected from MgX 1 X 2 and MgX 1 X 2 ·m(R″OH)·nE·qH2O (1), where m is 1-5, n is 0-1, and q is 0-0.8; X 1 and X 2Each is one of chlorine and bromine; R″ is a C1-C4 alkyl group; E is an electron-donating compound. The titanium-containing compound is titanium trihalide and the general formula Ti(OR′). 4－ m X′ m At least one of the titanium compounds shown, where R′ is C1-C 10 The alkyl group, X′ is a halogen, and m is an integer from 0 to 4.

[0120] In the mixture, the amount of magnesium halide and / or magnesium halide adduct is calculated based on elemental magnesium, and the molar ratio of component A, component B, component C, magnesium halide and / or magnesium halide adduct, and titanium-containing compound is (0.01-0.25):(0.01-0.25):(0.05-0.35):1:(15-90);

[0121] The amount of titanium-containing catalyst is calculated based on titanium element, the amount of alkyl aluminum is calculated based on aluminum element, the molar ratio of titanium-containing catalyst to alkyl aluminum is 1:(1-2000), and the molar ratio of alkyl aluminum to external electron donor is 1:(0.005-0.5).

[0122] The alkylaluminum and the external electron donor are reacted as a mixture of two components with a titanium-containing catalyst.

[0123] The molar ratio of alkylaluminum to propylene in the catalyst system is 1:(7500-55000).

[0124] The polypropylene prepared using this preferred embodiment has a molar content of mm less than or equal to 97.4%, a molar content of mmmm greater than or equal to 91.6%, and a molar ratio of mmmm to mm greater than or equal to 95.85%. The polypropylene has a half-peak width of melting peak greater than or equal to 6°C. The polypropylene also has higher nominal tensile strain at break and higher tensile stress at break, which is beneficial for the production and performance improvement of fiber products, flat yarn products and film materials.

[0125] In a particularly preferred embodiment of the present invention, the catalyst system comprises a titanium-containing catalyst, alkylaluminum, and an external electron donor; wherein the titanium-containing catalyst is prepared from a mixture comprising component A, component B, component C, a magnesium halide adduct, and a titanium-containing compound; wherein component A is selected from at least one hydroxybenzoyl compound, component B is selected from at least one alkoxybenzoyl compound, and component C is selected from at least one ester compound and / or ether compound, wherein component C is different from components A and B; wherein component A is selected from 2-hydroxybenzoic acid compounds and / or 2-hydroxybenzoic acid ester compounds; component B is selected from 2-alkoxybenzoic acid compounds and / or 2-alkoxybenzoic acid ester compounds; and component C is selected from at least one polyaryl aromatic carboxylic acid ester and a 1,3-diether compound of formula (IV).

[0126] Among them, R 1 R 2 R 5 and R 6 It is hydrogen;

[0127] R 7 and R 8 Each is a C1-C4 straight-chain or branched alkyl group, R 3 It is one of methyl, ethyl, n-propyl, and isopropyl, R 4 It is one of ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, isopentyl, 2-ethylhexyl, cyclopentyl, cyclohexyl, methylcyclohexyl, phenyl, and benzyl;

[0128] The magnesium halide adduct has the general formula shown in formula (1);

[0129] MgX 1 X 2 ·m(R″OH)·nE·qH2O (1), where m is 1-5, n is 0-1, and q is 0-0.8; X 1 and X 2 Each is one of chlorine and bromine; R″ is a C1-C4 alkyl group; E is an electron-donating compound;

[0130] In the catalyst system, the amount of magnesium halide adduct is calculated based on magnesium element, and the molar ratio of component A, component B, component C, magnesium halide adduct, and titanium-containing compound is (0.01-0.25):(0.01-0.25):(0.05-0.35):1:(15-90).

[0131] In the catalyst system, the amount of alkylaluminum is calculated as aluminum, and the amount of external electron donor is such that, relative to 1 mol of alkylaluminum, the amount of external electron donor is 0.01-0.4 mol.

[0132] A third aspect of the present invention provides a polypropylene prepared by the preparation method provided by the present invention.

[0133] A fourth aspect of the present invention provides polypropylene fibers and / or polypropylene fiber products prepared from the polypropylene provided by the present invention.

[0134] The fifth aspect of the present invention provides the application of polypropylene with a molar content of mm less than or equal to 97.4%, a molar content of mmmm greater than or equal to 91.6%, a molar content of mmmm to a molar content of mm greater than or equal to 95.85%, and a half-peak width of the melt peak greater than or equal to 6°C in polypropylene fibers and / or polypropylene fiber products.

[0135] The present invention will be described in detail below through examples and comparative examples. Unless otherwise specified, the methods used in the following examples are conventional; the reagents and materials used are commercially available unless otherwise specified.

[0136] Example 1

[0137] (1) Preparation of olefin polymerization catalysts

[0138] In a stirred 300 mL glass reaction flask fully purged with high-purity nitrogen, 90 mL of titanium tetrachloride and 18 mL of anhydrous hexane were added. The mixture was cooled to -20 °C, and 8 g of spherical magnesium chloride adduct MgCl2·2.7CH3CH2OH·0.02E (E being ethyl o-methoxybenzoate) (prepared according to the method in CN101486722A) was added. The mixture was stirred at -20 °C for 30 min. Then, the temperature was slowly increased to 110 °C, and during the heating process, 0.4 mL of ethyl 2-hydroxybenzoate, 1.5 mL of diisobutyl phthalate, and 0.2 mL of ethyl 2-methoxybenzoate were added. After reacting at 110 °C for 30 min, the liquid was filtered off. Add 80 mL of titanium tetrachloride, heat to 120 °C, maintain at 120 °C for 30 min, and then filter out the liquid. Add another 80 mL of titanium tetrachloride, heat to 120 °C, maintain at 120 °C for 30 min, and then filter out the liquid. Finally, wash the obtained solid five times with hexane at 60 °C (80 mL hexane per wash); and vacuum dry the obtained solid to obtain a spherical catalyst. The titanium content in the catalyst was determined by hydrogen peroxide colorimetric spectrophotometry using a 752s UV-Vis spectrophotometer from Shanghai Lingguang Technology Co., Ltd., and the titanium content in the catalyst was found to be 2.4 wt%.

[0139] (2) Preparation of polypropylene resin

[0140] Propylene liquid-phase bulk polymerization was carried out in a 5L stainless steel high-pressure reactor. Under nitrogen protection, 5 mL of a triethylaluminum hexane solution (concentration 0.5 mmol / mL), 1 mL of a cyclohexylmethyldimethoxysilane hexane solution (concentration 0.1 mmol / mL), and 9 mg of the aforementioned spherical catalyst component were added sequentially to the reactor to obtain the catalyst system. The high-pressure reactor was closed, and hydrogen and 2.3 L of liquid propylene were added, with the hydrogen concentration in the liquid propylene being 2500 ppm. The temperature was raised to 70°C, and the reaction was carried out for 1 hour. Then, the temperature was lowered, the pressure was released, the product was discharged, and dried to obtain polypropylene.

[0141] Example 2

[0142] The catalyst and polypropylene were prepared according to the method of Example 1, except that in step (2), the amount of hydrogen was adjusted so that the concentration of hydrogen in liquid propylene was 1400 ppm, and polypropylene was obtained.

[0143] Example 3

[0144] The catalyst and polypropylene were prepared according to the method of Example 1, except that the amounts of ethyl 2-hydroxybenzoate and ethyl 2-methoxybenzoate differed from those in Example 1. Specifically, in step (1), the amount of ethyl 2-hydroxybenzoate was 0.2 mL, and the amount of ethyl 2-methoxybenzoate was 0.8 mL. The titanium content in the catalyst was 2.5 wt%.

[0145] In step (2), the spherical catalyst prepared in step (1) is used. Polypropylene is obtained.

[0146] Example 4

[0147] The catalyst and polypropylene were prepared according to the method of Example 3, except that in step (1), "8g of spherical magnesium chloride adduct MgCl2·2.7CH3CH2OH·0.02E (E is ethyl o-methoxybenzoate) (prepared according to the method in CN1267508C); 0.4mL of ethyl 2-methoxybenzoate" replaced "8g of spherical magnesium chloride adduct MgCl2·2.7CH3CH2OH·0.02E (E is ethyl o-methoxybenzoate) (prepared according to the method in CN101486722A); 0.8mL of ethyl 2-methoxybenzoate". The titanium content in the obtained catalyst was 2.3wt%.

[0148] In step (2), the spherical catalyst prepared in step (1) is used. Polypropylene is obtained.

[0149] Comparative Example 1

[0150] The catalyst and polypropylene were prepared according to the method of Example 1, except that ethyl 2-hydroxybenzoate and ethyl 2-methoxybenzoate were not added in step (1). The titanium content in the catalyst was 2.2 wt%.

[0151] In step (2), the spherical catalyst prepared in step (1) is used. Polypropylene is obtained.

[0152] Comparative Example 2

[0153] The catalyst and polypropylene were prepared according to the method of Example 1, except that ethyl 2-methoxybenzoate was not added in step (1). The titanium content in the catalyst was 2.4 wt%.

[0154] In step (2), the spherical catalyst prepared in step (1) is used. Polypropylene is obtained.

[0155] Comparative Example 3

[0156] The catalyst and polypropylene were prepared according to the method of Example 1, except that an equal weight of the spherical catalyst of Example 1 was replaced with a catalyst component of grade DQC401. The titanium content in this catalyst was 2.2 wt%. Polypropylene was obtained.

[0157] Comparative Example 4

[0158] The catalyst and polypropylene were prepared according to the method of Comparative Example 1, except that the type of spherical magnesium chloride adduct was different. Specifically, in step (1), "8g spherical magnesium chloride adduct MgCl2·2.89CH3CH2OH·0.017LB1·0.040LB2·0.032LB3 (LB1 is ethyl 2-methoxybenzoate, LB2 is ethyl 2-hydroxybenzoate, LB3 is methanol) (prepared according to the method in CN105622644B)" replaced "8g spherical magnesium chloride adduct MgCl2·2.7CH3CH2OH·0.02E (E is ethyl 2-methoxybenzoate) (prepared according to the method in CN101486722A)". The titanium content in the obtained catalyst was 2.1wt%.

[0159] In step (2), the spherical catalyst obtained in step (1) is used to obtain polypropylene.

[0160] Example 5

[0161] The catalyst and polypropylene were prepared according to the method of Example 1, except that the type of component C was different when preparing the olefin polymerization catalyst, and the amount of hydrogen used in the propylene polymerization was different. Specifically, in step (1), "1.2 mL of 2-isopropyl-2-isopentyl-1,3-dimethoxypropane" was used instead of "1.5 mL of diisobutyl phthalate"; in step (2), the amount of hydrogen was adjusted so that the concentration of hydrogen in liquid propylene was 1400 ppm. The titanium content in the obtained catalyst was 2.7 wt%.

[0162] In step (2), the spherical catalyst obtained in step (1) is used. Polypropylene is obtained.

[0163] Comparative Example 5

[0164] The catalyst and polypropylene were prepared according to the method of Example 5, except that ethyl 2-methoxybenzoate was not added in step (1). The titanium content in the catalyst was 2.6 wt%.

[0165] In step (2), the spherical catalyst obtained in step (1) is used. Polypropylene is obtained.

[0166] Comparative Example 6

[0167] The catalyst and polypropylene were prepared according to the method of Example 5, except that ethyl 2-hydroxybenzoate and ethyl 2-methoxybenzoate were not added in step (1). The titanium content in the catalyst was 2.8 wt%.

[0168] In step (2), the spherical catalyst obtained in step (1) is used. Polypropylene is obtained.

[0169] Example 6

[0170] The catalyst and polypropylene were prepared according to the method of Example 1, except that in step (1), "0.4 mL of ethyl 4-hydroxybenzoate" was used instead of "0.4 mL of ethyl 2-hydroxybenzoate". The titanium content in the obtained catalyst was 2.2 wt%.

[0171] In step (2), polypropylene is obtained by using the spherical catalyst prepared in step (1).

[0172] Example 7

[0173] The catalyst and polypropylene were prepared according to the method of Example 1, except that in step (1), "0.2 mL of 2-methoxybenzoate" was replaced with "0.2 mL of 4-methoxybenzoate". The titanium content in the obtained catalyst was 2.3 wt%.

[0174] In step (2), polypropylene is obtained by using the spherical catalyst prepared in step (1).

[0175] Example 8

[0176] The catalyst and polypropylene were prepared according to the method of Example 1, except that in step (2), "1 mL of cyclohexylmethyldimethoxysilane in hexane (concentration 0.1 mmol / mL)" was replaced with "0.24 mL of cyclohexylmethyldimethoxysilane in hexane (concentration 0.1 mmol / mL)". Polypropylene was then obtained.

[0177] Example 9

[0178] The catalyst and polypropylene were prepared according to the method of Example 1, except that in step (2), the amount of hydrogen was adjusted so that the concentration of hydrogen in liquid propylene was 300 ppm, and the melt index of the obtained polypropylene was further adjusted to 27 g / 10 min by adding a degradation agent (3,6,9-triethyl-3,6,9-trimethyl-1,4,7-triperoxynonane). Polypropylene was obtained.

[0179] Comparative Example 7

[0180] The catalyst and polypropylene were prepared according to the method in Example 7 of CN104558298A, except that the amount of hydrogen was adjusted so that the concentration of hydrogen in the liquid propylene was 3150 ppm. The titanium content in the catalyst was 2.8 wt%. Polypropylene was obtained.

[0181] Comparative Example 8

[0182] The catalyst and polypropylene were prepared according to the method of Comparative Example 1 in CN104558298A. The difference was that the polypropylene obtained after propylene polymerization was further adjusted to a melt index of 27.1 g / 10 min by adding a degrading agent (3,6,9-triethyl-3,6,9-trimethyl-1,4,7-triperoxynonane). Polypropylene was thus obtained. The titanium content in this catalyst was 2.2 wt%.

[0183] Test Example 1

[0184] The melt index, mm content, mm-mm content, enthalpy of melt, molecular weight distribution, intrinsic viscosity and tensile properties of polypropylene prepared in each example and comparative example were measured respectively, and the results are shown in Table 1.

[0185] The testing methods involved are as follows:

[0186] 1. Polymer melt index (MI): Measured according to ASTM D1238-99.

[0187] 2. Polymer mm and mmmm content: The polymer was analyzed using an AVANCE 400 nuclear magnetic resonance spectrometer from Bruker, Switzerland. 13C-NMR test.

[0188] 3. Polymer melting enthalpy: The enthalpy was determined using a Perkin-Elmer DSC-7 differential scanning calorimeter according to the method specified in GB / T 19466 Differential Scanning Calorimetry (DSC) for Plastics.

[0189] 4. Polymer intrinsic viscosity: Measured at 160℃ using a CRYSTEX-QC instrument from Polymer Char, Spain.

[0190] 5. Tensile properties: The tensile properties of polypropylene resin were determined according to the method specified in GB / T 1040.1-2018.

[0191] 6. Molecular weight distribution: Measured using a PL-GPC220 gel permeation chromatography system with a Polymer Laboratory MIXED-B column, 1,2,4-trichlorobenzene as solvent, operating temperature of 150℃, and polystyrene as the standard.

[0192] Table 1

[0193] Table 1 (continued)

[0194] The results in Table 1 show that the polypropylene prepared in Comparative Examples 1-4 and Comparative Example 8 has low mm and mm / mm ratios, and a low mm / mm ratio. It also has relatively low enthalpy of melt and intrinsic viscosity. This results in high nominal strain at tensile break for the corresponding polypropylene, but insufficient tensile stress at break, leading to a decrease in the mechanical strength of the final product. The narrow melt half-peak width indicates that the nominal strain at tensile break will decrease rapidly over time during long-term use. Comparative Example 3, while having a relatively high mm / mm ratio and a relatively wide melt half-peak width, suffers from low mm content and a relatively wide molecular weight distribution, which negatively impacts the improvement of tensile stress at break. The polypropylene prepared in Comparative Examples 5-7, although exhibiting high tensile stress at break, shows a significant decrease in nominal strain at break. This is a result of the combined effects of high mm content, high enthalpy of melt, narrow melt half-peak width, and high intrinsic viscosity in its molecular structure. In summary, compared to existing technologies, the polypropylene resin structure of this invention has a relatively low content of the mm component (not exceeding 97.4%) and a relatively high content of the mmmm component (not less than 91.6%), providing the resin with both high tensile stress at break and high nominal strain at break. In a preferred embodiment, the resin has a melting enthalpy not exceeding 108 J / g and a melt half-peak width greater than or equal to 6.5°C. Combined with good intrinsic viscosity and a moderate molecular weight distribution, this exhibits the unique molecular structure characteristics of the polypropylene of this invention, further improving the resin's tensile stress at break and nominal strain at break, which is more conducive to improving the processing performance of subsequent products.

[0195] Furthermore, Example 6 changed the type of hydroxybenzoyl compound in component A. Compared with Example 1, although the melt index, mm content, mm-mm content, enthalpy of melt, melt half-width, molecular weight distribution, and intrinsic viscosity of the obtained polypropylene were still within the preferred range, the tensile properties were reduced. Example 7 changed the type of alkoxybenzoyl compound in component B. Compared with Example 1, the mm-mm / mm ratio of the obtained polypropylene was lower, the intrinsic viscosity did not meet the optimal conditions, and the tensile properties were also reduced. Example 8 changed the amount of external electron donor. Compared with Example 1, the mm-mm / mm ratio of the obtained polypropylene was lower, and the melt index, mm-mm content, and intrinsic viscosity of the polypropylene did not meet the preferred conditions. The tensile properties, especially the tensile stress at break, were significantly reduced. This shows that when the types of components A and B, and the amount of external electron donor meet the preferred conditions, the tensile stress at break and the nominal strain at break of the obtained polypropylene can be further improved.

[0196] Example 9 is an embodiment of propylene polymerization at low hydrogen concentration using the catalyst system and preparation method of Example 1, followed by further degradation of the polymer to the preferred melt index range of this invention. The resulting polypropylene exhibits molecular structure characteristics consistent with optimal technical features, and its mechanical properties demonstrate optimal tensile fracture stress and nominal tensile fracture strain. Comparative Example 8 also employs a technical solution of further degradation after propylene polymerization at low hydrogen concentration, but uses a catalyst system similar to Comparative Example 3. Although the degradation method overcomes the wide molecular weight distribution of the polypropylene prepared in Comparative Example 3 and improves the content of mm and mmmm and the mmmm / mm ratio of polypropylene to some extent, the still excessively low mmmm content and narrow melt half-peak width affect the improvement of polypropylene tensile fracture stress and the subsequent processing performance of the product.

[0197] Figure 1 is a DSC curve of polypropylene prepared in Examples 1, 9 and Comparative Example 8. As can be seen from Figure 1, compared with the polypropylene in Comparative Example 8, the polypropylene in Examples 1 and 9 has a wider half-peak width at half-peak.

[0198] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A polypropylene, characterized in that, The polypropylene has a molar content of mm less than or equal to 97.4%, a molar content of mmmm greater than or equal to 91.6%, and a molar ratio of mmmm to mm greater than or equal to 95.85%; the polypropylene has a half-peak width of 6°C or greater than or equal to 6°C.

2. The polypropylene according to claim 1, characterized in that, The polypropylene contains 97.1% or less mm in molar content and 92-95.5% mm in molar content. Preferably, the molar content of mm in the polypropylene is less than or equal to 97.1%, and the molar content of mmmm is 92.3-95%. Preferably, the ratio of the molar content of mmmm to the molar content of mm is greater than or equal to 96%, more preferably greater than or equal to 96.1%; Preferably, the half-maximum width at half maximum (WHM) of the melting peak of the polypropylene is greater than or equal to 6.5°C, more preferably 6.5-10°C.

3. The polypropylene according to claim 1 or 2, characterized in that, The melting enthalpy of the polypropylene is less than or equal to 108 J / g, preferably less than or equal to 105 J / g; And / or, the molecular weight distribution of the polypropylene is 3-7, preferably 3-6; And / or, the intrinsic viscosity of the polypropylene is 1.3-1.9 dL / g, preferably 1.35-1.85 dL / g, more preferably 1.4-1.85 dL / g; And / or, the polypropylene has a melt index of 8.5-45 g / 10 min at 230 °C and 2.16 kg, preferably 9-30 g / 10 min, and more preferably 10-30 g / 10 min.

4. A method for preparing polypropylene, characterized in that, The preparation method includes the following steps: polymerizing a propylene-containing material in the presence of hydrogen and a catalyst system; wherein, The catalyst system comprises: a titanium-containing catalyst, alkyl aluminum, and an optional external electron donor; wherein the titanium-containing catalyst is prepared from a mixture of components A, B, C, magnesium halides and / or magnesium halide adducts, and titanium-containing compounds. The preparation method of the titanium-containing catalyst includes: Step (1): Optionally, prepare magnesium halide adducts; Step (2): Mix component A, component B, component C, magnesium halide and / or the magnesium halide adduct and titanium-containing compound; Component A is selected from at least one of hydroxybenzoyl compounds, component B is selected from at least one of alkoxybenzoyl compounds, and component C is selected from at least one of ester compounds and / or ether compounds, wherein component C is different from components A and components B.

5. The preparation method according to claim 4, characterized in that, The polymerization reaction is carried out at a temperature of 60-80℃ for 0.5-3 hours. Preferably, during the polymerization reaction, the amount of hydrogen used is such that the concentration of hydrogen in the propylene-containing material is 300-4500 ppm, more preferably 300-3500 ppm.

6. The preparation method according to claim 4 or 5, characterized in that, In the mixture, the amount of magnesium halide and / or magnesium halide adduct, calculated based on elemental magnesium, is such that the molar ratio of component A, component B, component C, magnesium halide and / or magnesium halide adduct, and titanium-containing compound is (0.005-0.4):(0.005-0.4):(0.01-0.5):1:(5-100), preferably (0.01-0.25):(0.01-0.25):(0.05-0.35):1:(15-90), and more preferably (0.02-0.18):(0.02-0.18):(0.05-0.25):1:(25-80); Preferably, in the catalyst system, the amount of titanium-containing catalyst is calculated based on titanium element, the amount of alkyl aluminum is calculated based on aluminum element, and the molar ratio of titanium-containing catalyst to alkyl aluminum is 1:(1-2000), preferably 1:(20-700). And / or, in the catalyst system, the amount of alkylaluminum is calculated as aluminum, and the amount of external electron donor is such that, relative to 1 mol of alkylaluminum, the amount of external electron donor is 0.005-0.5 mol, preferably 0.01-0.4 mol.

7. The preparation method according to any one of claims 4-6, characterized in that, The hydroxybenzoyl compounds are selected from the compounds shown in formula (I). in, R1is one of hydrogen, C1-C 20 linear or branched alkyl, C3-C 20 substituted or unsubstituted cycloalkyl, C6-C 20 substituted or unsubstituted aryl and C7-C 20 substituted or unsubstituted aralkyl; R2, R3, R4and R5are each independently one of hydrogen, halogen, nitro, C1-C 20 linear or branched alkyl, C3-C 20 substituted or unsubstituted cycloalkyl, C6-C 20 substituted or unsubstituted aryl and C7-C 20 substituted or unsubstituted aralkyl; The alkoxybenzoyl compounds are selected from those shown in formula (II). in, R6 is hydrogen, C1-C 20 Straight-chain or branched alkyl groups, C3-C 20 Substituted or unsubstituted cycloalkyl, C6-C 20 Substituted or unsubstituted aryl groups and C7-C 20 One of the substituted or unsubstituted aralkyl groups; R7 is C1-C 20 Straight-chain or branched alkyl groups, C3-C 20 Substituted or unsubstituted cycloalkyl, C6-C 20 Substituted or unsubstituted aryl groups and C7-C 20 One of the substituted or unsubstituted aralkyl groups; R8, R9, R 10 and R 11 Each is independently hydrogen, halogen, nitro, C1-C 20 Straight-chain or branched alkyl groups, C3-C 20 Substituted or unsubstituted cycloalkyl, C6-C 20 Substituted or unsubstituted aryl groups and C7-C 20 One of the substituted or unsubstituted aralkyl groups; And / or, the ester compound is selected from polyary aromatic carboxylic acid esters, preferably from polyary aromatic carboxylic acid alkyl esters, and more preferably from diary aromatic carboxylic acid alkyl esters; And / or, the ether compound is selected from the 1,3-diether compounds shown in formula (IV). in, R 1 R 2 R 3 R 4 R 5 and R 6 Each is independently hydrogen, halogen, C1-C 20 Straight-chain or branched alkyl groups, C3-C 20 Substituted or unsubstituted cycloalkyl, C6-C 20 Substituted or unsubstituted aryl groups and C7-C 20 One of the substituted or unsubstituted aralkyl groups; R 7 and R 8 Each independently is C1-C 20 Straight-chain or branched alkyl groups, C3-C 20 Substituted or unsubstituted cycloalkyl, C6-C 20 Substituted or unsubstituted aryl groups and C7-C 20 One of the substituted or unsubstituted aralkyl groups.

8. The preparation method according to any one of claims 4-7, wherein, The magnesium halide adduct has the general formula shown in formula (1); MgX 1 X 2 ·m(R″OH)·nE·qH2O Formula (1) Where m is 1-5, n is 0-1, and q is 0-0.8; X 1 and X 2 Each is either chlorine or bromine; R″ is a C1-C4 alkyl group; E is an electron-donating compound.

9. A polypropylene prepared by the method according to any one of claims 4-8.

10. A polypropylene fiber and / or polypropylene fiber article made from the polypropylene of claim 9.

11. The application of a polypropylene having a molar content of mm less than or equal to 97.4%, a molar content of mmmm greater than or equal to 91.6%, a molar content of mmmm to the molar content of mm greater than 95.85%, and a half-peak width of the melt peak greater than or equal to 6°C in polypropylene fibers and / or polypropylene fiber products.

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