Polypropylene wax and preparation method thereof

Abstract

The invention relates to a preparation method of polypropylene wax and the polypropylene wax prepared by the method. According to the preparation method of the polypropylene wax, alkane or mixed alkane is used as a polymerization solvent, a metallocene catalyst and a non-metallocene catalyst are used as main catalysts, alkyl aluminum, aluminoxane or boride is used as a cocatalyst, and propylene is subjected to solution polymerization. The polymerization method is high in polymerization activity, mild in polymerization condition, easy to operate and high in volatile component removal efficiency, and the obtained polypropylene wax is extremely low in metal content, low in VOC content and easy to further process.

Description

Technical Field

[0001] This invention relates to a method for preparing polypropylene wax, and the polypropylene wax obtained by the method. Existing technology

[0002] Polypropylene (PP), as one of the general-purpose resins, is well-known. With the development of new applications for polypropylene, its manufacture and functionalization as a polyolefin wax has become one of the new hot topics in polymer materials internationally.

[0003] Polyolefin wax, also known as low molecular weight polyolefin, is waxy at room temperature and typically refers to polyolefins with a molecular weight between 500 and 10,000 g / mol. Industrial production of polyolefin wax began abroad as early as the 1950s. Currently, it and its downstream products are increasingly widely used and in greater demand as a new type of fine chemical. Polyolefin wax has good chemical stability, is colorless, odorless, and non-toxic, and is widely used in masterbatch dispersants, plastic processing aids, PVC lubricants, asphalt, hot melt adhesives, cardboard coatings, paints, and other fields. High-quality polyolefin wax can also be used in cosmetics, personal care products, and food preservation materials.

[0004] Depending on the source of raw materials, polyolefin waxes can be classified into polyethylene wax, polypropylene wax, copolymer wax, modified wax, etc. Research on polyolefin waxes began with polyethylene wax, which has a lower melting point and a relatively simpler preparation process. Its production technology is the most mature, and its market application is also more widespread. Polypropylene wax generally refers to low molecular weight polypropylene with an average molecular weight ranging from one thousand to tens of thousands. Its molecular weight and molecular weight distribution are much smaller than ordinary high molecular weight polypropylene resin. In addition to possessing most of the advantages of polyethylene wax, polypropylene wax has a higher melting point and softening point, better compatibility, and higher hardness, giving it more special properties and applications, especially in the field of high-temperature resistant products, where it has seen rapid development in recent years.

[0005] The production processes of polypropylene wax mainly include the following three types: First, direct polymerization of propylene under the action of a catalyst to obtain low molecular weight polypropylene; second, the cracking or degradation products of high molecular weight polypropylene; and third, the separation and purification of oligomers as byproducts during the polymerization of high molecular weight polypropylene. Among these, the third method, due to advancements in polypropylene catalyst technology, rarely produces low molecular weight byproducts in the industrial production of polypropylene, and therefore has no practical value. The second method uses high molecular weight polypropylene as raw material, preparing polypropylene wax through high-temperature thermal cracking or peroxide catalytic degradation. This is currently the main production process in China and is popular in low- to mid-range applications. Its advantages include a relatively simple preparation process, low operating costs, abundant raw material sources, low equipment investment, and the ability to utilize recycled waste plastics for thermal cracking to obtain polypropylene wax products. The degradation of high molecular weight polypropylene mainly involves two methods: thermal degradation and peroxide-catalyzed degradation. However, both thermal and peroxide degradation follow a free radical reaction mechanism, making it difficult to precisely control the structure of the degradation products. They typically require very high temperatures to degrade into lower molecular weight waxes, resulting in high energy consumption, difficulty in controlling product quality, batch instability, wide molecular weight distribution, and a tendency to develop black spots. Furthermore, the addition of peroxides can introduce odor problems, and the high double bond content in the degradation products can easily cause yellowing, leading to poor product quality and limiting its application in high-end fields. Therefore, direct polymerization to obtain polypropylene wax offers unique advantages.

[0006] There are different process routes for the direct polymerization production of polypropylene wax. Traditional Ziegler-Natta catalysts have poor hydrogen sensitivity and are generally suitable for preparing high molecular weight polypropylene. To obtain low molecular weight polypropylene wax, a large amount of hydrogen needs to be added during polymerization. However, the addition of high-concentration hydrogen not only increases the practical difficulty of operation but also significantly reduces the catalyst's polymerization activity, making it uneconomical. Furthermore, the product has a wide molecular weight distribution and high ash content, making it difficult to obtain high-quality polypropylene wax. Metallocene catalysts, due to their high hydrogen sensitivity and narrow molecular weight distribution of the polymerization products, are a better choice for the direct polymerization production of polypropylene wax.

[0007] Patent CN98115939.7 discloses a method for preparing polypropylene wax using an ethylene-bridged metallocene compound as a catalyst. In this method, the catalyst component is added to liquid propylene in solution form to undergo a bulk polymerization reaction, and the polypropylene wax product is discharged as a melt. Because the melting point of polypropylene wax is much higher than the polymerization reaction temperature, and the polymer melt viscosity is high, pipeline blockage is easily caused during the discharge process, making it difficult to implement in actual production. Patent US4962248A discloses a method for preparing polypropylene wax using a homogeneous metallocene catalyst. In this method, a non-bridged bismetallocene catalyst (such as bis(neomenthylcyclopentadienyl)zirconium dichloride) is used as the catalyst, and methylaluminoxane is used as the co-catalyst. The catalyst and co-catalyst are dissolved separately in toluene solution, and after a period of prepolymerization, they are added together to liquid propylene to undergo a bulk polymerization reaction. This method uses hydrogen as a molecular weight regulator, and the polypropylene wax product is also ultimately discharged as a melt. Patent CN 105622807A uses a liquid-phase bulk polymerization process with a supported metallocene catalyst and hydrogen as a molecular weight regulator to catalyze the polymerization of liquid propylene to directly obtain granular polypropylene wax products. This method is simple to operate, but the polymerization activity is low, only reaching about 1000–3000 times / hour. Patent CN109422830A uses a homogeneous bridged metallocene catalyst as the main catalyst, methylaluminoxane as a co-catalyst, and diethylzinc as a molecular weight regulator to catalyze the liquid-phase or gas-phase polymerization of propylene. This method can efficiently produce low molecular weight polypropylene with a narrow molecular weight distribution; however, the introduction of diethylzinc increases the metal impurity content in the polypropylene wax product, affecting product quality. Summary of the Invention

[0008] The purpose of this invention is to provide a polypropylene wax and its preparation method, wherein the preparation method has high polymerization activity (up to 10). 5 gPP / gcat) has the advantages of mild polymerization conditions, easy operation, high efficiency in removing volatiles, and extremely low metal content in the resulting polymer (residual amount less than 5 mg / kg).

[0009] To achieve the above objectives, the present invention provides a method for preparing polypropylene wax, characterized by comprising the following steps:

[0010] In a catalytic system comprising at least one main catalyst selected from metallocene catalysts and non-metallocene catalysts, and at least one co-catalyst selected from alkylaluminum, aluminoxane, and boride, propylene is polymerized in the presence of hydrogen in a polymerization solvent selected from an alkane solvent with a boiling point of 5-55°C or a mixed alkane solvent with a saturated vapor pressure of 20-150 kPa (preferably 40-110 kPa) at 20°C, to obtain polypropylene wax, wherein the molar ratio of propylene to hydrogen is (500-5):1, preferably (300-10):1.

[0011] On the other hand, the present invention provides a polypropylene wax with a weight-average molecular weight M w Its concentration ranges from 600 to 30000 g / mol, its dispersion index (PDI) ranges from 1.0 to 4.0, and its density ranges from 0.890 to 0.920 g / cm³. 3 Crystallinity is 15-62%, melting point T m The temperature range is 120–165℃, the Brookfield viscosity (at 170℃) is 30–15000 mPa·s, and the enthalpy of melting ΔH is 30–125 J / g.

[0012] Compared with the prior art, the polypropylene wax provided by the present invention has a narrow molecular weight distribution, high melting point and crystallinity, wide melt viscosity control range, and high grafting rate during graft modification. It can be used as a dispersant, lubricant or processing aid, which is beneficial to improving dispersion uniformity, precipitation uniformity and processing fluidity.

[0013] Through in-depth research, the inventors of this invention discovered that using alkane solvents with boiling points of 5-55°C or mixed alkane solvents with saturated vapor pressures of 20-150 kPa (preferably 40-110 kPa) at 20°C as polymerization solvents, under the polymerization system and conditions of this invention, not only does the resulting polypropylene wax exhibit excellent physical properties, but it also improves the subsequent devolatilization efficiency of the polymer for processing. The resulting polymer has a VOC content of less than 100 ppm, or even less than 80 ppm, which is very beneficial for reducing polymer post-processing costs and minimizing polymer odor.

[0014] The preparation method provided by this invention has high polymerization activity (up to 10). 5 gPP / gcat) has mild polymerization conditions and is easy to operate. The resulting polymer has extremely low metal content (residual amount less than 5mg / kg), making it more suitable for high-end applications with extremely high requirements for metal content, such as food packaging, medical packaging, and cosmetics. Attached Figure Description

[0015] Figure 1 This is the GPC spectrum of the polymer obtained in Example 13.

[0016] Figure 2This is the DSC spectrum of the polymer obtained in Example 13.

[0017] Figure 3 This is the carbon NMR spectrum of the polymer obtained in Example 13. Detailed Implementation

[0018] The specific embodiments of the present invention will be described in detail below. However, it should be noted that the scope of protection of the present invention is not limited to these specific embodiments, but is determined by the claims in the appendix.

[0019] Any specific numerical values ​​disclosed herein (including the endpoints of numerical ranges) are not limited to their exact values, but should be understood to also include values ​​close to the exact value, such as all possible values ​​within ±10% of the exact value. Furthermore, with respect to the disclosed numerical ranges, one or more new numerical ranges can be obtained by arbitrarily combining the endpoint values ​​of the range, the endpoint values ​​with specific point values ​​within the range, and the specific point values ​​themselves; these new numerical ranges should also be considered as specifically disclosed herein.

[0020] Unless otherwise stated, the terms used herein have the same meaning as commonly understood by those skilled in the art, and if a term is defined herein and its definition differs from the common understanding in the art, the definition herein shall prevail.

[0021] In the context of this invention, unless otherwise explicitly defined or the meaning is beyond the understanding of those skilled in the art, hydrocarbon or hydrocarbon derivative groups having three or more carbon atoms (such as propyl, propoxy, butyl, butane, butene, butenyl, hexane, etc.) have the same meaning when not prefixed with "n-" as when prefixed with "n-". For example, propyl is generally understood as n-propyl, and butyl is generally understood as n-butyl, unless otherwise explicitly defined.

[0022] In this invention, except where expressly stated, any matters or issues not mentioned herein are directly applicable to aspects known in the art without any modification. Furthermore, any implementation described herein can be freely combined with one or more other implementations described herein, and the resulting technical solutions or concepts are considered part of the original disclosure or original record of this invention, and should not be regarded as new content not disclosed or anticipated herein, unless those skilled in the art consider the combination clearly unreasonable.

[0023] All patent and non-patent literature mentioned in this article, including but not limited to textbooks and journal articles, are incorporated in full by way of citation.

[0024] In the context of this invention, unless otherwise specified, the physical properties of substances (such as boiling point) are measured at room temperature (25°C) and normal pressure (101325 Pa).

[0025] As described above, in a first aspect, the present invention provides a method for preparing polypropylene wax, characterized by comprising the following steps:

[0026] In a catalytic system comprising at least one main catalyst selected from metallocene catalysts and non-metallocene catalysts, and at least one co-catalyst selected from alkylaluminum, aluminoxane, and boride, propylene is polymerized in the presence of hydrogen in a polymerization solvent selected from an alkane solvent with a boiling point of 5-55°C or a mixed alkane solvent with a saturated vapor pressure of 20-150 kPa (preferably 40-110 kPa) at 20°C, to obtain polypropylene wax, wherein the molar ratio of propylene to hydrogen is (500-5):1, preferably (300-10):1.

[0027] Through in-depth research, the inventors of this invention discovered that by using metallocene and / or non-metallocene catalysts as the main catalyst and any one selected from alkylaluminum, aluminoxane, and borides as the co-catalyst, polypropylene wax (hereinafter sometimes referred to as the polypropylene of this invention or low molecular weight polypropylene) can be prepared by solution polymerization of propylene in the presence of hydrogen using a specific polymerization solvent. The polypropylene of this invention has a low molecular weight and a narrow molecular weight distribution; furthermore, the polypropylene wax has a low VOC content and minimal odor, while the metal content as impurities in the polypropylene wax is further reduced (residual amount less than 5 mg / kg). The resulting polypropylene wax is more likely to achieve a high degree of branching during graft modification.

[0028] In this invention, the weight-average molecular weight M of the polypropylene wax is... w The concentration ranges from 600 to 30000 g / mol.

[0029] In this invention, the polymerization solvent is selected from alkane solvents with boiling points of 5-55°C or mixed alkane solvents with saturated vapor pressure of 20-150 kPa (preferably 40-110 kPa) at 20°C.

[0030] Among them, the alkane solvent with a boiling point of 5-55℃ is preferably an alkane solvent with a boiling point of 5-50℃, such as 2,2-dimethylpropane (also known as neopentane, boiling point 9.5℃), 2-methylbutane (also known as isopentane, boiling point 27.83℃), n-pentane (boiling point 36.1℃), cyclopentane (boiling point 49.26℃), and preferably n-pentane, isopentane, cyclopentane, n-hexane, and cyclohexane.

[0031] Among them, the mixed alkane solvent with a saturated vapor pressure of 20-150 kPa (preferably 40-110 kPa) at 20°C refers to a mixed solvent formed by mixing different alkane solvents, such as a solvent obtained by mixing solvents of pentane and its isomers. It can also come from a mixture of alkanes cut off according to the distillation range in a solvent distillation unit, such as n-pentane and isopentane, isopentane and neopentane, n-pentane and cyclopentane, n-pentane and neopentane, isopentane and cyclopentane, neopentane and cyclopentane, n-pentane-isopentane-cyclopentane, n-hexane-isohexane-cyclohexane, etc.

[0032] In one embodiment of the present invention, the polymerization solvent may be selected from n-pentane, isopentane, neopentane, and cyclopentane, or may be a mixed alkane solvent with a saturated vapor pressure of 20-150 kPa (preferably 40-110 kPa) at 20°C, formed by mixing two or more alkanes selected from n-pentane, isopentane, neopentane, and cyclopentane. Preferably, it may be selected from a combination of n-pentane and isopentane, a combination of isopentane and neopentane, a combination of n-pentane and cyclopentane, a combination of n-pentane and neopentane, a combination of isopentane and cyclopentane, a combination of neopentane and cyclopentane, a combination of n-hexane and n-pentane, and a combination of n-pentane-isopentane-cyclopentane.

[0033] In this invention, there are no particular limitations on the polymerization temperature and polymerization pressure; conventional polymerization temperatures and pressures used in the field for preparing low molecular weight polypropylene can be adopted.

[0034] In one embodiment of the present invention, the polymerization temperature is 90-160°C, preferably 100-150°C.

[0035] In one embodiment of the invention, the polymerization pressure is 1.5-6.0 MPa, preferably 2.0-5.0 MPa.

[0036] In this invention, propylene is polymerized in a polymerization solvent in the presence of hydrogen within a catalytic system comprising a main catalyst and a co-catalyst to obtain polypropylene wax; at this time, the molar ratio of propylene to hydrogen is (500-5):1, preferably (300-10):1. In this invention, no other comonomers besides propylene are used to form the propylene copolymer.

[0037] It is known to those skilled in the art that all the foregoing method steps are preferably carried out under substantially anhydrous and oxygen-free conditions. "Substantially anhydrous and oxygen-free" here means that the water and oxygen content in the system is consistently less than 100 ppm. Furthermore, the metallocene catalyst of the present invention typically needs to be stored under sealed conditions in the presence of a slightly positive pressure inert gas (such as nitrogen, argon, helium, etc.) for later use.

[0038] In this invention, there is no particular limitation on the amount of the main catalyst; conventional catalyst amounts in the art can be used. In one embodiment of this invention, the concentration of the main catalyst in the polymerization solvent is 0.1 × 10⁻⁶ atoms, calculated based on the central metal atom. -5 mol / L~50×10 -5 mol / L, preferably 0.5×10 -5 mol / L~20×10 - 5 mol / L, more preferably 1×10 -5 mol / L~10×10 -5 mol / L.

[0039] In this invention, the main catalyst is at least one selected from metallocene catalysts and non-metallocene catalysts. More specifically, the main catalyst can be selected from metallocene catalysts, non-metallocene catalysts, or a mixture of metallocene catalysts and non-metallocene catalysts.

[0040] In this invention, when the main catalyst is selected from metallocene catalysts, there is no particular limitation on the type of metallocene catalyst; catalysts conventionally used in propylene polymerization in the art can be used. There is also no particular limitation on the form of the catalyst; it can be a supported metallocene catalyst or an unsupported metallocene catalyst, with an unsupported metallocene catalyst being preferred.

[0041] More specifically, as metallocene catalysts, such as invention patents CN201110247347.2, CN201110080343.X, CN201010518904.5, CN201010519660.2, CN201210289014.0, CN200910078596.6, CN201310090758.4, CN201310090736.8, CN201310521768.9, CN201410589467.4, CN201410590067.5, CN201610835700.1, CN201610944191.6, CN201710 959423.X, CN201110247349.1, CN201110080294.X, CN201110080395.7, CN 201210289017.4, CN201210289031.4, CN201310091192.7, CN201310540973 .X, CN201510724626.1, CN200410086283.2, CN200610137777.8, CN201610 944182.7, CN201710312720.5, CN201110080422.0,, CN201110080394.2, CN 201010519406.2, CN201010519715.X, CN201010519174.0, CN20101051942 9.3, CN201210289004.7, CN201310090847.9, CN201310091209.9, CN20131 0540975.9, CN201410554709.6, CN201410513506.2, CN00130388.0, CN200 710176589.0, CN201610944083.9, CN201110246705.8, CN201110247085.X, CN2011102914899, CN201010521674.8, CN201310090752.7, CN2013100908 48.3, CN2013100908483, CN201510624502.6, CN201710166709.2, CN201710 31225.2, CN201110246710.9, CN201110080374.5, CN201010519797.8, CN2 01210289012.1, CN201210418645.8, CN201310090998.4, CN201410252254.2. Metallocene catalysts described in CN201610393399.3, CN201610956141.X, CN201710958837.0, etc.

[0042] In one embodiment of the present invention, when the main catalyst comprises a metallocene catalyst, a single metallocene catalyst may be used, or a combination of multiple metallocene catalysts may be used.

[0043] In this invention, when the main catalyst is selected from non-metallocene catalysts, there is no particular limitation on the type of non-metallocene catalyst; catalysts conventionally used in propylene polymerization in the art can be used. There is also no particular limitation on the form of the catalyst; it can be a supported non-metallocene catalyst or an unsupported non-metallocene catalyst. An unsupported non-metallocene catalyst is preferred.

[0044] Specifically, as non-metallocene catalysts, such as those specified in invention patents CN200310106156.X, CN200310106157.4, CN200410066068.6, CN200510119401.X, CN200610107651.6, CN200710162677.5, CN200710162667.1, CN200710162672.2, CN200710162675.6, CN200710162676.0, CN200710162666.7, CN200910180100.6, CN200910180607.1, CN200 910180601.4, CN200910180606.7, CN200910180602.9, CN200910180605. 2. CN200910180603.3, CN200910180604.8, CN200910210988.3, ​​CN2009102 10984.5, CN200910210989.8, CN200910210986.4, CN200910210985.X, CN2 00910210990.0, CN200910210987.9, CN200910210991.5, CN201010286008 .0, CN201010286012.7, CN201010284870.8, CN201010285982.5, CN20101 0284856.8, CN201010285970.2, CN201010285956.2, CN201010285969.X, C N201010285958.1, CN201010285967.0, CN201010285994.8, CN2011102593 36.6, CN201110259219.X, CN201110259330.9, CN201110259327.7, CN2011 10259367.1, CN201110259289.5, CN201110259359.7, CN201110259282.3 , CN201110259318.8, CN201110259258.X, CN201110259300.8, CN20111025 9254.1, CN201110259245.2, CN201110259296.5, CN201110259338.5, CN20 1110259370.3, CN201110259339.X, CN201110259293.1, CN201110259356.3. CN201210063756.1, CN201210063777.3, CN201210063788.1, CN20121006 3818.9, CN201210063824.4, CN201210063843.7, CN201210063854.5, CN2012 10063876.1, CN201210063878.0, CN201210063891.6, CN201210063894.X, C N201210063907.3, CN201210063909.2, CN201210063935.5, CN201210063941 The non-metallocene catalysts described in CN201210063945.9, CN201310189677.X, CN201310227368.7, CN201310227370.4, CN201310227830.3, CN201310227393.5, CN201310452714.1, CN201710814678.7, CN201710814595.8, CN201710814594.3, CN201710814593.9, CN201710814592.4, CN201710814591.X, CN201310091208.4, etc.

[0045] In one embodiment of the present invention, when the main catalyst comprises a non-metallocene catalyst, one non-metallocene catalyst may be used, or a combination of multiple non-metallocene catalysts may be used.

[0046] In one embodiment of the present invention, the non-metallocene catalyst is any one of the metal complexes represented by general formula (I) or a mixture thereof in any proportion:

[0047]

[0048] In formula (I), groups R1, R2, R3, R4, R6, R7, R8, and R9 are each independently selected from hydrogen, optionally substituted C1-C6 straight-chain or branched alkyl groups, optionally substituted C2-C6 straight-chain or branched alkenyl groups, optionally substituted C2-C6 straight-chain or branched alkynyl groups, halogens, optionally substituted C1-C6 straight-chain or branched alkoxy groups, or optionally substituted C6-C6... 10 Aryl, or, wherein two adjacent groups are bonded to each other to form an optionally substituted C4-C8 ring together with the carbon atom to which they are attached, preferably each independently selected from hydrogen and optionally substituted C1-C6 straight-chain or branched alkyl groups, more preferably each independently selected from hydrogen, methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl, tert-butyl.

[0049] R5 is selected from hydrogen, C1-C 12 Straight-chain or branched hydrocarbon groups, or C3-C 12 Cyclic hydrocarbon group, preferably hydrogen, C1-C6 straight-chain or branched alkyl group, C6-C 10 Aryl, more preferably hydrogen, C1-C3 straight-chain or branched alkyl or phenyl, more preferably hydrogen, methyl, ethyl, propyl, isopropyl or phenyl;

[0050] R 10 Each is independently selected from hydrogen or C1-C6 straight-chain or branched hydrocarbon groups, preferably hydrogen or C1-C6 straight-chain or branched alkyl groups, more preferably hydrogen, methyl or ethyl; p is selected from 1 or 2;

[0051] Group Y is selected from O or S, preferably O; group Z is selected from S or O, preferably S;

[0052] M is selected from Group IVB metal elements, preferably titanium, zirconium, or hafnium;

[0053] Group X is selected from fluorine, chlorine, bromine and iodine, preferably chlorine or bromine;

[0054] Indicates a single bond or a double bond, where when When it is a single bond, then p is a hydrogen atom present at 2 and N. When it is a double bond, then p is 1 and the hydrogen on N is absent;

[0055] ------ indicates a coordinate bond, covalent bond, or ionic bond;

[0056] n depends on the valence state of atom M, and can be 1, 2, 3, 4, or 5.

[0057] In one embodiment of the invention, groups R1, R2, R3, R4, R7, and R9 are each independently selected from hydrogen, optionally substituted C1-C6 straight-chain or branched alkyl groups, optionally substituted C2-C6 straight-chain or branched alkenyl groups, optionally substituted C2-C6 straight-chain or branched alkynyl groups, halogens, optionally substituted C1-C6 straight-chain or branched alkoxy groups, or optionally substituted C6-C6... 10 Aryl, or wherein two adjacent groups are bonded to each other to form an optionally substituted C4-C8 ring together with the carbon atom to which they are attached; preferably, each is independently selected from hydrogen, optionally substituted C1-C6 straight-chain or branched alkyl; more preferably, each is independently selected from hydrogen, methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl, tert-butyl; even more preferably, each is independently selected from hydrogen, methyl, ethyl.

[0058] In one embodiment of the invention, groups R6 and R8 are each independently selected from hydrogen, optionally substituted C1-C6 straight-chain or branched alkyl groups, optionally substituted C2-C6 straight-chain or branched alkenyl groups, optionally substituted C2-C6 straight-chain or branched alkynyl groups, halogens, optionally substituted C1-C6 straight-chain or branched alkoxy groups, or optionally substituted C6-C6... 10 Aryl; preferably, each is independently selected from optionally substituted C1-C6 straight-chain or branched alkyl groups; more preferably, each is independently selected from optionally substituted C3-C6 straight-chain or branched alkyl groups; even more preferably, each is independently selected from propyl, isopropyl, butyl, isobutyl, sec-butyl, tert-butyl.

[0059] In one embodiment of the present invention, R5 is selected from hydrogen, C1-C6 straight-chain or branched alkyl groups, C6-C 10 The aryl group is preferably selected from hydrogen, C1-C3 straight-chain or branched alkyl groups, and phenyl groups; more preferably, it is selected from hydrogen, methyl, ethyl, propyl, isopropyl, and phenyl groups.

[0060] In one embodiment of the present invention, R 10 Each is independently selected from hydrogen, C1-C6 straight-chain or branched alkyl groups, preferably hydrogen or C1-C6 straight-chain or branched alkyl groups, more preferably hydrogen, methyl, or ethyl.

[0061] In one embodiment of the present invention, the group Y is selected from O.

[0062] In one embodiment of the present invention, the group Z is selected from S.

[0063] In one embodiment of the present invention, in formula (I), the group M is selected from group IVB metals of the periodic table, such as titanium, zirconium and hafnium, more preferably titanium.

[0064] In one embodiment of the invention, in formula (I), group X is a halogen, including fluorine, chlorine, bromine and iodine, wherein chlorine or bromine is preferred.

[0065] In one embodiment of the present invention, in formula (I), the symbol ------ represents a coordinate bond.

[0066] In this invention, n depends on the valence state of atom M, and n is the valence state of atom M minus 1, for example, it can be 1, 2, 3, 4 or 5.

[0067] In a further preferred embodiment, the non-metallocene catalyst is preferably any one of or a mixture thereof having the following chemical structural formulas:

[0068]

[0069] In a more preferred embodiment, the non-metallocene catalyst is more preferably one or more metal complexes having the following chemical structural formulas:

[0070]

[0071] In one embodiment of the present invention, the metallocene catalyst is selected from any one of the metal complexes represented by general formula (II) or a mixture thereof in any proportion:

[0072]

[0073] In formula (II), R' is a C1-C8 straight-chain or branched alkylene group, or a di-C6-C... 10 arylalkylene, diC1-C8 alkylsilylene or diC6-C 10 Arylmethylenesilyl, preferably C1-C4 straight-chain or branched alkylene, diphenylalkylene, diC1-C4 alkylmethylenesilyl or diphenylmethylenesilyl, more preferably methylene, ethylene, isopropylene, diphenylmethylene, dimethylmethylenesilyl or diphenylmethylenesilyl;

[0074] Each independently represents an unsubstituted or substituted compound selected from 1 to 5 alkyl groups, each independently selected from halogens, C1-C4 alkyl groups, C1-C4 haloalkyl groups, or C6-C4 alkyl groups. 10 The aryl group is substituted with cyclopentadienyl, fluorenyl, indene, tetrahydroindene, benzo[a]indene, or benzo[a]dihydroindene;

[0075] M is a Group IVB metal, preferably titanium or zirconium;

[0076] Each X is independently selected from halogen, C1-C6 alkyl or C2-C6 alkenyl; each is independently selected from halogen; more preferably chlorine or bromine.

[0077] In one embodiment of the present invention, Each can be independently represented as an unsubstituted cyclopentadienyl, fluorenyl, indene, tetrahydroindene, benzo[a]indene, or benzo[a]dihydroindene.

[0078] In one embodiment of the present invention, Each independently represents one to five elements independently selected from halogens, C1-C4 alkyl groups, C1-C4 haloalkyl groups, or C6-C4 alkyl groups. 10 The aryl group is substituted with cyclopentadienyl, fluorenyl, indene, tetrahydroindene, benzo[a]indene, or benzo[b]dihydroindene. The substituents on the sample are preferably each independently selected from methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl, tert-butyl, and phenyl. The number of substituents can be 1, 2, 3, 4, or 5.

[0079] In a further preferred embodiment, the metallocene catalyst is preferably selected from ethylene bis-1-indenyl zirconium dichloride, ethylene bis-1-(2-methyltetrahydroindenyl) zirconium dichloride, ethylene bis-1-(4,7-dimethylindenyl) zirconium dichloride, ethylene bis-1-(2-methyl-4-phenylindenyl) zirconium dichloride, ethylene bis-1-(2-methyl-4,5-benzoindenyl) zirconium dichloride, and ethylene bis-1-(2-methyl-4,5-benzo-6,7-dihydroindenyl) zirconium dichloride. The zirconium dichloride (indene), ethylene bis-1-(2-methylindene) zirconium dichloride, ethylene bis-1-tetrahydroindene zirconium dichloride, dimethylmethylenesilyl bis-1-indene zirconium dichloride, dimethylmethylenesilyl bis-1-(4,5,6,7-tetrahydro-1-indene) zirconium dichloride, dimethylmethylenesilyl bis-1-(2-methylindene) zirconium dichloride, dimethylmethylenesilyl bis-1-(2-methyl-4-phenylindene) zirconium dichloride, or any mixture thereof in any proportion.

[0080] It should be noted that the aforementioned non-metallocene and metallocene catalysts can be used alone or mixed in any proportion. When used in combination, the ratio of non-metallocene to metallocene catalysts is not particularly limited. Based on the number of central active metal atoms in each catalyst, the molar ratio can be 1:100 to 100:1, or 1:50 to 50:1, or 1:10 to 10:1, for example, 1:1.

[0081] In this invention, the co-catalyst is selected from at least one of alkylaluminum, aluminoxane, and boride. For each type of co-catalyst, alkylaluminum, aluminoxane, or boride can be selected from one or more of the following: for example, one or more alkylaluminum, one or more aluminoxane, or one or more boride.

[0082] In one embodiment of the present invention, the alkylaluminum used as a co-catalyst has the general structural formula shown in formula (IIIa).

[0083] Al(R)3 (IIIa)

[0084] In this embodiment, each group R is independently selected from C1-C8 alkyl groups, preferably from methyl, ethyl, propyl, isopropyl, butyl, isobutyl, and n-hexyl, and more preferably from ethyl, isobutyl, or n-hexyl. The alkylaluminum can be used alone or in combination in any proportion.

[0085] Specifically, examples of alkylaluminum include trimethylaluminum (Al(CH3)3), triethylaluminum (Al(CH3CH2)3), tri-n-propylaluminum (Al(n-C3H7)3), triisopropylaluminum (Al(i-C3H7)3), triisobutylaluminum (Al(i-C4H9)3), and tri-n-pentylaluminum (Al(n-C5H7)3).11 )3) Tri-n-hexyl aluminum (Al(n-C6H) 13 3) Diethylmethylaluminum (Al(CH3)(CH3CH2)2) and dimethylethylaluminum (Al(CH3)2(CH3CH2)), preferably selected from trimethylaluminum, triethylaluminum, triisobutylaluminum or tri-n-hexylaluminum.

[0086] In one embodiment of the present invention, the aluminum oxane used as a co-catalyst has the general structural formula shown in formula (IIIb) or (IIIc).

[0087]

[0088] In this embodiment, each group R is independently selected from C1-C8 alkyl groups, preferably from methyl, ethyl, propyl, isopropyl, butyl, isobutyl, or n-hexyl, more preferably from methyl, ethyl, or isobutyl, and n is any integer in the range of 1-50, preferably any integer in the range of 10-30. The alkylaluminoxane can be used alone or in combination in any proportion.

[0089] Specifically, the aluminum oxane is preferably selected from methylaluminoxane, ethylaluminoxane, isobutylaluminoxane, n-butylaluminoxane, n-hexylaluminoxane, triisobutylaluminum-modified methylaluminoxane, and tri-n-hexylaluminum-modified methylaluminoxane, and more preferably from methylaluminoxane, triisobutylaluminum-modified methylaluminoxane, or tri-n-hexylaluminum-modified methylaluminoxane.

[0090] In one embodiment of the present invention, the boride used as a co-catalyst is selected from triphenylborane, tris(pentafluorophenyl)borane, triphenylcarbazo(pentafluorophenyl)borate, N,N-dimethylphenylammonium tetra(pentafluorophenyl)borate, triethylammonium tetra(pentafluorophenyl)borate, 1-butyl-3-methylimidazolium tetrafluoroborate, ferrocene tetrafluoroborate, trimethylammonium tetraphenylborate, triethylammonium tetraphenylborate, triisopropylammonium tetraphenylborate, tri-n-butylammonium tetraphenylborate, trimethylammonium tetra(4-methylphenyl)borate, and triisopropylammonium tetra(4-methylphenyl)borate. One or more of trimethylammonium tetra(2,4-dimethylphenyl)borate, triethylammonium tetra(2,4-dimethylphenyl)borate, trimethylammonium tetra(4-trifluoromethylphenyl)borate, tri-n-butylammonium tetra(4-trifluoromethylphenyl)borate, tri-n-butylammonium tetra(pentafluorophenyl)borate and N,N-diethylphenylammonium tetra(pentafluorophenyl)borate, more preferably selected from one or more of tri(pentafluorophenyl)boron, triphenylcarbon tetra(pentafluorophenyl)borate, N,N-dimethylphenylammonium tetra(pentafluorophenyl)borate and triethylammonium tetra(pentafluorophenyl)borate.

[0091] It should be noted that in this invention, "C6-C" 10"Aryl" refers to a hydrocarbon group with 6-10 carbon atoms that has aromatic properties; specifically, it can be phenyl or naphthyl.

[0092] In this invention, "C4-C8 ring" refers to a cyclic group having 4-8 cyclic carbon atoms. It can be an unsaturated or saturated ring, and can be aromatic or non-aromatic. When it is an unsaturated ring, it can have one, two, or three double bonds; for example, it can be a cyclopentene ring or a cyclopentadiene ring. When it is an aromatic ring, it can be a benzene ring.

[0093] In this invention, "C3-C" 12 "Cyclic hydrocarbon group" refers to a cyclic group having 3-12 cyclic carbon atoms. This ring can be unsaturated or saturated, and can be aromatic or non-aromatic. Examples of saturated cyclic hydrocarbon groups include cyclopropyl, cyclobutyl, and cyclopentyl. When unsaturated, it can have one, two, or three double bonds; for example, it can be cyclopentenyl or cyclopentadienyl. When aromatic, it can be phenyl or naphthyl.

[0094] In this invention, the substituents used in "optional substitution" or "optionally (substitutable)" are selected from halogens, C1-C6 alkyl groups, C3-C6 cycloalkyl groups, C1-C6 haloalkyl groups, phenyl groups, and halophenyl groups. More specifically, they may be selected from: fluorine, chlorine, bromine, iodine, methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl, tert-butyl, pentyl and its isomers, hexyl and its isomers, cyclobutyl, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, halomethyl (e.g., trifluoromethyl), haloethyl (e.g., trifluoroethyl, pentafluoroethyl), halopropyl, haloisopropyl, halobutyl, haloisobutyl, halosec-butyl, halotert-butyl, halopentyl, halohexyl, phenyl, and halophenyl groups (e.g., chlorophenyl, dichlorophenyl, pentafluorophenyl). Unless otherwise specified, the maximum number of substituents is the maximum number of positions on the substituted group that can be substituted. More specifically, the number of substituents can be 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10. For example, it can be 1-8, 1-6, 1-5, 1-4, 1-3, or 1-2. When multiple substituents are present, the substituents can be the same or different.

[0095] In this invention, "halogen atom" or "halogen" refers to fluorine, chlorine, bromine or iodine, preferably fluorine, chlorine or bromine.

[0096] In this invention, unless otherwise specified, the upper limit of the number of substituents in "optionally substituted" is the upper limit of the positions on the substituted group that can be substituted, and the number of substituents can be 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10. For example, it can be 1-8, 1-6, 1-5, 1-4, 1-3, or 1-2. When there are multiple substituents, the substituents can be the same or different.

[0097] In one embodiment of the present invention, the total amount of the co-catalyst alkylaluminum and / or aluminoxane added to the reaction system, based on aluminum atoms, and the total amount of the main catalyst (non-metallocene catalyst and / or metallocene catalyst), based on the central metal atoms, have a molar ratio (co-catalyst / main catalyst) of (10-5000):1, preferably (100-2000):1, more preferably (250-1200):1.

[0098] In one embodiment of the present invention, the total amount of the co-catalyst boride added to the reaction system, based on boron atoms, and the total amount of the main catalyst (non-metallocene catalyst and / or metallocene catalyst), based on the central metal atoms, have a molar ratio (co-catalyst / main catalyst) of (1-10):1, preferably (2-5):1.

[0099] In the preparation of the low molecular weight polypropylene of the present invention, a chain transfer agent may or may not be used, preferably without a chain transfer agent. As the chain transfer agent, other metal alkyl compounds besides the co-catalysts listed above can be included, for example, one or more of n-butyllithium, diethylzinc, dipropylzinc, dibutylzinc, diisobutylzinc, diethylmagnesium, dibutylmagnesium, or n-butylethylmagnesium. In one embodiment of the present invention, when a chain transfer agent is used, the molar ratio of the amount of chain transfer agent (based on its metal content) to the total amount of the main catalyst (non-metallocene catalyst and / or metallocene catalyst) (based on the number of central metal atoms) is 1-300:1, preferably 10-200:1.

[0100] Furthermore, the cocatalysts alkylaluminum, aluminoxane, and borides are generally used in solution form. There are no particular limitations on the solvent used when preparing the cocatalyst solution, as long as it can dissolve / disperse the cocatalyst. The solvent is generally selected from alkane solvents, such as n-pentane, isopentane, cyclopentane, neopentane, etc., or aromatic solvents, such as toluene, ethylbenzene, xylene, etc. According to the present invention, for ease of subsequent separation, it is preferable to use the same solvent as the polymerization solvent; or the same solvent as one of the solvents in the mixed solvents used for polymerization.

[0101] In the polymerization preparation method of polypropylene wax of the present invention, the propylene solution polymerization reactor is not limited to any type, as long as it can achieve contact between propylene and a catalyst containing a main catalyst and a co-catalyst in the solvent, and polymerization is carried out within the polymerization pressure and temperature range described in the present invention, and can effectively avoid material adhesion and aggregation. In one embodiment of the present invention, the reactor is a stirred tank reactor, and its stirring speed is not particularly limited, as long as it can ensure that the solution in the reactor can be properly dispersed. The stirring speed is related to the reactor volume. Generally speaking, the smaller the reactor volume, the higher the required stirring speed. The stirring speed is 10-1000 rpm, preferably 20-500 rpm.

[0102] In the preparation method described in this invention, the form in which propylene enters the reactor is not limited. Propylene can be directly pumped into the reactor in the form of liquid propylene through a propylene pump, or it can be first evaporated into gaseous propylene through a propylene preheater before being pumped into the reactor.

[0103] In the preparation method of this invention, the catalytic system comprises a homogeneous single-center catalyst as the main catalyst and one or more mixtures selected from aluminoxanes, alkylaluminates, or borides as co-catalysts. The catalyst can be added to the polymerization reaction system first, followed by the co-catalyst; or first, the co-catalyst is added, followed by the main catalyst; or the two are first mixed and then added together; or they are added simultaneously. When the main catalyst and co-catalyst are added separately, they can be added sequentially in the same feeding line or sequentially in multiple feeding lines. When both are added simultaneously, multiple feeding lines should be selected.

[0104] The polymerization method of the present invention can polymerize propylene continuously or in a batch manner.

[0105] In this invention, there is no limitation on the polymerization time; those skilled in the art can select the appropriate polymerization time as needed.

[0106] Following the polymerization method of the present invention, polypropylene can be recovered from the polymerization solvent using conventional techniques in the art. For example, after the polymerization reaction is complete, the polymerization solvent can be removed by flash evaporation, and the polypropylene can then be further purified as needed.

[0107] Secondly, the present invention provides a polypropylene wax with a weight-average molecular weight M w Its concentration ranges from 600 to 30000 g / mol, its dispersion index (PDI) ranges from 1.0 to 4.0, and its density ranges from 0.890 to 0.920 g / cm³. 3 Crystallinity is 15-62%, melting point T mThe temperature range is 120–165℃, the Brookfield viscosity (at 170℃) is 30–15000 mPa·s, and the enthalpy of melting ΔH is 30–125 J / g.

[0108] In one embodiment of the present invention, the weight-average molecular weight M of the polypropylene wax is... w Its concentration ranges from 1000 to 30000 g / mol, its dispersion index (PDI) ranges from 1.3 to 3.5, its crystallinity ranges from 25% to 58%, and its melting point is T. m The temperature range is 130–165℃, the Brookfield viscosity (at 170℃) is 45–14000 mPa·s, and the enthalpy of melting ΔH is 52–120 J / g.

[0109] In one embodiment of the present invention, the weight-average molecular weight M of the polypropylene wax is... w Its concentration is 1000–18000 g / mol, its dispersibility index (PDI) is 1.3–3.5, its crystallinity is 25–58%, and its melting point is T. m The temperature range is 130–156℃, the Brookfield viscosity (at 170℃) is 45–10000 mPa·s, and the enthalpy of melting ΔH is 52–120 J / g.

[0110] In one embodiment of the present invention, the polypropylene wax is prepared by the polypropylene wax preparation method of the present invention.

[0111] Example

[0112] The embodiments of the present invention will be described in detail below with reference to examples. However, those skilled in the art will understand that the following examples are only for illustrating the present invention and should not be regarded as limiting the scope of the present invention.

[0113] The molecular weight and distribution of the polymers obtained in the following examples were determined using the following methods: Referring to GB / T 21864-2005 standard, a Polymer Laboratories PL-220 gel permeation chromatography system was used. 1,2,4-trichlorobenzene was used as the mobile phase, polystyrene as the standard, a differential detector was used, the flow rate was 1.0 mL / min, the measurement temperature was 150 °C, and the sample concentration was 2.0 mg / mL. The polymer dispersibility index (PDI) was calculated based on the measured weight-average molecular weight and number-average molecular weight.

[0114] The melt viscosity of the polymers obtained in the following examples was tested using a Brookfield DV2T viscometer at a test temperature of 170°C, in accordance with DIN 53019.

[0115] The melting point, enthalpy of fusion, and crystallinity of the polymers obtained in the following examples were tested using a differential scanning calorimeter (Perkin-Elmer DSC 7) in accordance with GB / T28724-2012 standard. The sample amount was 3-5 mg, and the atmosphere was nitrogen. The sample was first heated from 30°C to 200°C at a rate of 20°C / min, held for 3 min, then cooled to 20°C at a rate of 20°C / min, held for 3 min, and then heated back to 200°C at a rate of 20°C / min. The second heating curve was used for analysis.

[0116] The density of the polymers obtained in the following examples and comparative examples was tested using an Anton Paar DMA4500M densitometer at 23°C, in accordance with ISO 1183 standard.

[0117] Propylene solution polymerization method: The main catalyst and co-catalyst are dissolved separately in polymerization solvent in a glove box and then added sequentially to the catalyst feeding tank for later use. A 300L high-pressure reactor is purged with high-purity nitrogen at 100°C for 6 hours. Then, 120L of polymerization solvent is added to the reactor, the atmosphere is vented, and stirring is started. After the reactor is heated to the set temperature, propylene and hydrogen are added to the reactor in a specific ratio using a flow meter. Once the reactor pressure reaches the set pressure, the catalyst solution from the catalyst feeding tank is added to the reactor to initiate the propylene solution polymerization reaction. The ratio of gaseous propylene to hydrogen in the reactor is controlled at the set value using online chromatography. Propylene and hydrogen feeding is stopped once the propylene absorption reaches the set value. The polymer solution in the reactor is flash-evaporated in a flash tank to remove the solvent, yielding the final polymer. The polymer is weighed, and the polymerization activity is calculated.

[0118] Application experiment of polymer grafting modification: A certain amount of polymer was weighed and transferred to a multi-necked reaction flask equipped with a stirrer. A certain amount of toluene solvent was added, and the mixture was heated and stirred to dissolve the polymer. A certain amount of methacrylic acid, styrene, and benzoyl peroxide were weighed and mixed with toluene to prepare a mixed solution for later use. At a certain temperature, the above mixed solution was slowly added dropwise to the multi-necked reaction flask. After the addition was complete, the temperature was kept constant and the reaction was continued to be stirred for 5 hours to terminate the reaction. After cooling to room temperature, the product was poured into a pre-prepared acetone solvent and allowed to stand for a period of time. The supernatant was poured into a waste liquid container, and a certain amount of toluene was added to dissolve it. The mixture was then poured into acetone again for precipitation. This process was repeated several times. The solid product obtained from the precipitation was filtered, dried, and finally extracted with distilled water in a Soxhlet extractor for two days. After that, it was placed in a vacuum oven and dried to constant weight to obtain the grafted polymer.

[0119] Grafting rate determination: Weigh approximately 0.2 g of the grafted product and dissolve it in 30 mL of toluene. Heat the solution under reflux for half an hour, then cool. Add excess potassium hydroxide-ethanol solution and continue reflux for 1 hour to allow for complete reaction. After cooling, add excess hydrochloric acid-isopropanol solution and react for a period of time. Cool to the set temperature. Use phenolphthalein as an indicator and perform back titration with potassium hydroxide-ethanol solution under constant temperature conditions. The grafting rate is calculated using the following formula:

[0120]

[0121] In the formula, Gd represents the grafting rate, in percentage (%); C KOH V represents the concentration of potassium hydroxide-ethanol solution, expressed in mol / L; KOH This indicates the volume of potassium hydroxide-ethanol solution added and consumed during titration, in mL; C HCl V represents the concentration of the hydrochloric acid-isopropanol solution, in mol / L; HCl The volume of hydrochloric acid-isopropanol solution added is expressed in mL; W represents the mass of the grafted polymer, expressed in g.

[0122] The method for determining the metal content as an impurity is as follows: Inductively coupled plasma atomic emission spectrometry is used to detect the metal content. The polymer sample solution is carried into the nebulization system by the carrier gas and then nebulized. It enters the axial channel of the plasma in the form of an aerosol. It is fully evaporated, atomized, ionized and excited in the high temperature and inert gas. The characteristic spectral lines of the contained elements emitted are sent to the spectrometer by the spectrometer system. The spectrometer performs qualitative and quantitative analysis based on the characteristic spectra of the elements.

[0123] VOCs determination method: Gas chromatography (GC) is used to detect the VOCs content in the polymer. A quantitative amount of toluene is used as the extractant to extract residual solvent from the polymer. Based on the set parameters of the GC, a 10 μL micro-syringe is used to repeatedly draw the test solution to remove air bubbles. Then, 1 μL of the solution is injected into the GC. After the components of the sample are fully displayed in the chromatogram, the characteristic peak area of ​​the analyte is recorded. The content of the analyte in the test solution is calculated by comparing the characteristic peak area with the standard curve.

[0124] Examples 1-21 and Comparative Examples 1-2

[0125] Examples 1-21 and Comparative Examples 1-2 were carried out according to the propylene solution polymerization method described above and the conditions in Table 1 below.

[0126] The properties of the polymers obtained in Examples 1-21 and Comparative Examples 1-2 were measured according to the above-described measurement method. The results are shown in Table 2 below.

[0127]

[0128]

[0129]

[0130]

[0131] As can be seen from the comparison of the examples and comparative examples, the preparation method of the present invention has excellent polymerization activity and higher devolatilization efficiency, which can greatly reduce the cost of polymer post-processing. The obtained polymer has extremely low VOC content and metal residue, and has a lower odor, making it more suitable for high-end application fields such as food packaging, medical packaging and cosmetics.

[0132] As can be seen from the table above, the polymerization method of the present invention not only has higher polymerization activity, lower volatile matter and metal residue, but also the resulting polymer has a higher grafting rate when applied for polar group grafting modification.

[0133] Furthermore, as shown in the table above, when metallocene and non-metallocene catalysts are used together as mixed catalysts, the resulting polymer exhibits a higher grafting rate when applied for graft modification, thereby significantly reducing the cost of functional modification and giving it more advantageous application performance, making it more suitable for blending with other polar polymers.

[0134] While the specific embodiments of the present invention have been described in detail above, it should be noted that the scope of protection of the present invention is not limited to these specific embodiments, but is determined by the appended claims. Those skilled in the art can make appropriate modifications to these embodiments without departing from the technical concept and spirit of the present invention, and these modified embodiments are obviously also included within the scope of protection of the present invention.

Claims

1. A process for the preparation of a polypropylene wax, characterized in that, The process comprises the following steps: polymerizing propylene in the presence of hydrogen in a polymerization solvent selected from an alkane solvent having a boiling point of 5-55°C or a mixed alkane solvent having a saturated vapor pressure of 20-150 KPa (preferably 40-110 KPa) at 20°C in the presence of a catalytic system comprising a main catalyst selected from at least one of a metallocene catalyst, a non-metallocene catalyst, a cocatalyst selected from at least one of an aluminum alkyl, an aluminoxane, a boron compound, wherein the molar ratio of propylene to hydrogen is (500-5):1, preferably (300-10):1, to obtain a polypropylene wax.

2. The production method according to claim 1, wherein The polymerization solvent is one selected from n-pentane, isopentane, neopentane, cyclopentane, or a mixed alkane solvent formed by mixing two or more alkane selected from n-pentane, isopentane, neopentane and cyclopentane, preferably one selected from the combination of n-pentane and isopentane, isopentane and neopentane, n-pentane and cyclopentane, n-pentane and neopentane, isopentane and cyclopentane, neopentane and cyclopentane, n-hexane and n-pentane, and n-pentane-isopentane-cyclopentane.

3. The production method according to claim 1 or 2, wherein, The polymerization conditions satisfy: the polymerization temperature is 90-160°C, preferably 100-150°C; and / or, the polymerization pressure is 1.5-6.0 MPa, preferably 2.0-5.0 MPa; and / or, The concentration of the procatalyst in the polymerization solvent is 0.1 x 10 -5 mol / L to 50 x 10 -5 mol / L, preferably 0.5 x 10 -5 mol / L to 20 x 10 -5 mol / L, more preferably 1 x 10 -5 mol / L to 10 x 10 -5 mol / L, based on the central metal atom.

4. The method of producing according to any one of claims 1 to 3, wherein, The non-metallocene catalyst is any one or mixture of any ratio selected from the metal complex represented by the general formula (I): In formula (I), the groups R1, R2, R3, R4, R6, R7, R8, R9are each independently selected from hydrogen, optionally substituted C1-C6straight or branched alkyl, optionally substituted C2-C6straight or branched alkenyl, optionally substituted C2-C6straight or branched alkynyl, halogen, optionally substituted C1-C6straight or branched alkoxy or optionally substituted C6-C 10 aryl, or wherein two adjacent groups are bonded to each other, forming an optionally substituted C4-C8ring together with the carbon atoms to which they are attached, preferably each independently selected from hydrogen and optionally substituted C1-C6straight or branched alkyl, more preferably each independently selected from hydrogen, methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl, tert-butyl; R5 is selected from hydrogen, C1-C 12 Straight-chain or branched hydrocarbon groups, or C3-C 12 Cyclic hydrocarbon group, preferably hydrogen, C1-C6 straight-chain or branched alkyl group, C6-C 10 Aryl, more preferably hydrogen, C1-C3 straight-chain or branched alkyl or phenyl, more preferably hydrogen, methyl, ethyl, propyl, isopropyl or phenyl; R 10 each independently is selected from hydrogen or a C1-C6straight chain or branched chain alkyl group, preferably hydrogen or a C1-C6straight chain or branched chain alkyl group, more preferably hydrogen, methyl or ethyl; p is selected from 1 or 2; group Y is selected from O or S, preferably O; group Z is selected from S or O, preferably S; M is selected from the group IVB metal elements, preferably titanium, zirconium or hafnium; group X is selected from fluorine, chlorine, bromine and iodine, preferably chlorine or bromine; represents a single or double bond, wherein when is a single bond, then p is 2, the hydrogen on N is present, when is a double bond, then p is 1, the hydrogen on N is absent; represents a coordinate bond, a covalent bond or an ionic bond; n depends on the valence state of atom M, and can be 1, 2, 3, 4 or 5.

5. The method of producing according to any one of claims 1 to 4, wherein, The non-metallocene catalyst is any one or mixture of any ratio selected from the metal complex represented by the following formula: preferably any one or mixture of any ratio selected from the metal complex represented by the following formula:

6. The method of producing according to any one of claims 1 to 5, wherein, The metallocene catalyst is any one or mixture of any ratio selected from the metal complex represented by the general formula (II): In formula (II), R' is a C1-C8straight-chain or branched alkylene group, a di-C6-C10arylalkylene group, a di-C1-C8alkylsilyl group or a di-C6-C10arylsilyl group, preferably a C1-C4straight-chain or branched alkylene group, a di-C1-C4alkylsilyl group or a di-C6-C10arylsilyl group, more preferably a methylene group, an ethylene group, an isopropylidene group, a dimethylsilyl group or a diphenylsilyl group; and 10 In formula (II), R' is a C1-C8straight-chain or branched alkylene group, a di-C6-C10arylalkylene group, a di-C1-C8alkylsilyl group or a di-C6-C10arylsilyl group, preferably a C1-C4straight-chain or branched alkylene group, a di-C1-C4alkylsilyl group or a di-C6-C10arylsilyl group, more preferably a methylene group, an ethylene group, an isopropylidene group, a dimethylsilyl group or a diphenylsilyl group; and 10 In formula (II), R' is a C1-C8straight-chain or branched alkylene group, a di-C6-C10arylalkylene group, a di-C and each independently represents an unsubstituted or substituted cyclopentadienyl, fluorenyl, indenyl, tetrahydroindenyl, benzindenyl or benzo-C4-Ci0-dihydroindenyl group; 10 each independently represents an unsubstituted or substituted cyclopentadienyl, fluorenyl, indenyl, tetrahydroindenyl, benzindenyl or benzo-C4-Ci0-dihydroindenyl group; M is a group IVB metal, preferably titanium or zirconium; each X is independently selected from halogen, C1-C6 alkyl or C2-C6 alkenyl; each is independently selected from halogen; more preferably chlorine or bromine.

7. The method of producing according to any one of claims 1 to 6, wherein, The metallocene catalyst is any one selected from the group consisting of ethylenebis-1-indenylzirconium dichloride, ethylenebis-1-(2-methyltetrahydroindenyl)zirconium dichloride, ethylenebis-1-(4,7-dimethylindenyl)zirconium dichloride, ethylenebis-1-(2-methyl-4-phenylindenyl)zirconium dichloride, ethylenebis-1-(2-methyl-4,5-benzoindenyl)zirconium dichloride, ethylenebis-1-(2-methyl-4,5-benzo-6,7-dihydroindenyl)zirconium dichloride, ethylenebis-1-(2-methylindenyl)zirconium dichloride, ethylenebis-1-tetrahydroindenylzirconium dichloride, dimethylsilyl bis-1-indenylzirconium dichloride, dimethylsilyl bis-1-(4,5,6,7-tetrahydro-1-indenyl)zirconium dichloride, dimethylsilyl bis-1-(2-methylindenyl)zirconium dichloride, dimethylsilyl bis-1-(2-methyl-4-phenylindenyl)zirconium dichloride, or any mixture thereof in any ratio.

8. The production method according to any one of claims 1 to 7, characterized by, The aluminoxane is one or more selected from the group consisting of methylaluminoxane, ethylaluminoxane, isobutylaluminoxane, n-hexylaluminoxane, triisobutylaluminum-modified methylaluminoxane, tri-n-hexylaluminum-modified methylaluminoxane, preferably one or more selected from the group consisting of methylaluminoxane, triisobutylaluminum-modified methylaluminoxane, or tri-n-hexylaluminum-modified methylaluminoxane; The aluminum alkyl is one or more selected from the group consisting of trimethylaluminum, triethylaluminum, tripropylaluminum, triisobutylaluminum, tri-n-butylaluminum, triisopentylaluminum, tri-n-pentylaluminum, tri-n-hexylaluminum, triisohexylaluminum, diethylmethylaluminum, and dimethylethylaluminum, preferably one or more selected from the group consisting of trimethylaluminum, triethylaluminum, triisobutylaluminum, or tri-n-hexylaluminum, most preferably one or more selected from the group consisting of triethylaluminum or triisobutylaluminum; The boride is one or more selected from the group consisting of triphenylboron, tris(pentafluorophenyl)boron, trityl tetra(pentafluorophenyl)borate, N,N-dimethylanilinium tetra(pentafluorophenyl)borate, triethylammonium tetra(pentafluorophenyl)borate, 1-butyl-3-methylimidazolium tetrafluoroborate, ferrocenium tetrafluoroborate, trimethylammonium tetraphenylborate, triethylammonium tetraphenylborate, triisopropylammonium tetraphenylborate, tri-n-butylammonium tetraphenylborate, trimethylammonium tetra(4-methylphenyl)borate, triisopropylammonium tetra(4-methylphenyl)borate, trimethylammonium tetra(2,4-dimethylphenyl)borate, triethylammonium tetra(2,4-dimethylphenyl)borate, trimethylammonium tetra(4-trifluoromethylphenyl)borate, tri-n-butylammonium tetra(4-trifluoromethylphenyl)borate, tri-n-butylammonium tetra(pentafluorophenyl)borate, and N,N-diethylanilinium tetra(pentafluorophenyl)borate, preferably one or more selected from the group consisting of tris(pentafluorophenyl)boron, trityl tetra(pentafluorophenyl)borate, N,N-dimethylanilinium tetra(pentafluorophenyl)borate, or triethylammonium tetra(pentafluorophenyl)borate.

9. The production method according to any one of claims 1 to 8, wherein: The total amount of the alkylaluminum and the aluminoxane in the cocatalyst, calculated as aluminum atoms, has a molar ratio of (10-5000): 1, preferably (100-2000): 1, more preferably (250-1200): 1, to the total amount of the main catalyst, calculated as central metal atoms; and / or The total amount of the boride in the cocatalyst, calculated as boron atoms, has a molar ratio of (1-10): 1, preferably (2-5): 1, to the total amount of the main catalyst, calculated as central metal atoms.

10. The polypropylene wax prepared according to the process of any one of claims 1 to 9, characterized in that, The weight average molecular weight M w is 600 to 30,000 g / mol, the dispersity index PDI is 1.0 to 4.0, the density is 0.890 to 0.920 g / cm 3 , the crystallinity is 15 to 62%, the melting point T m is 120 to 170°C, the Brookfield viscosity (at a temperature of 170°C) is 30 to 15,000 mPa-s, and the melting enthalpy ΔH is 30 to 125 J / g.

11. The polypropylene wax according to claim 10, characterized in that, Its weight-average molecular weight M w Its concentration ranges from 1000 to 30000 g / mol, its dispersion index (PDI) ranges from 1.3 to 3.5, its crystallinity ranges from 25% to 58%, and its melting point is T. m The temperature range is 130–165℃, the Brookfield viscosity (at 170℃) is 45–14000 mPa·s, and the enthalpy of melting ΔH is 52–120 J / g.

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