Polypropylene powder for 3D printing, its preparation method and application

Abstract

The present invention relates to the technical field of polymer processing, and discloses a polypropylene powder for 3D printing, a preparation method and application thereof, a polypropylene composition for 3D printing, and an application thereof. The polypropylene powder contains polypropylene and an antioxidant; based on the total weight of the polypropylene powder, the polypropylene is 99-99.5 parts, and the antioxidant is 0.5-1 part; the molecular weight distribution index M w / M n is 4-8; the particle size distribution of the polypropylene powder is less than 2.5. The polypropylene powder is in the form of regular and uniform spherical particles and has a smooth surface, and can be directly used for selective laser sintering 3D printing.

Description

Technical Field

[0001] The present invention relates to the technical field of polymer processing, and specifically, to a polypropylene powder for 3D printing, a preparation method thereof, and an application thereof. Background Art

[0002] Selective Laser Sintering (SLS) technology is a rapid prototyping technology, which is the most widely used and most promising technology in the current additive manufacturing technology and has shown a rapid development trend in recent years. The SLS technology first scans a three-dimensional entity by a computer, and then irradiates the material powder pre-laid on a workbench or a component with a high-intensity laser, selectively melting and sintering it layer by layer, thereby realizing the layer-by-layer forming technology. The SLS technology has a high degree of design flexibility, can manufacture precise models and prototypes, can form components with reliable structures and can be directly used, and shortens the production cycle and simplifies the process. Therefore, it is particularly suitable for the development of new products.

[0003] Theoretically, the types of forming materials that can be used for the SLS technology are relatively wide, such as polymers, paraffins, metals, ceramics, and their composite materials. However, the performance and properties of the forming materials are an important factor for the successful sintering of the SLS technology, which directly affects the forming speed, accuracy, physical and chemical properties, and comprehensive properties of the formed parts. At present, polymer powder raw materials that can be directly applied to the SLS technology and successfully manufacture molded products with small dimensional errors, regular surfaces, and low porosity are rarely seen in the market. Therefore, it is urgent to develop and improve the types of polymers suitable for the SLS technology and their corresponding solid powder raw materials.

[0004] In the prior art, the powder raw materials suitable for SLS are usually prepared by a pulverization method, such as cryogenic pulverization. For example, a polypropylene powder obtained by cryogenic pulverization is disclosed in CN104031319A; it is classified and collected by an air flow sieve, and the polypropylene powder with a particle size in the range of 200-800 meshes is selected, and the coarse materials that do not meet the fineness requirements are returned to the silo for continued pulverization; 100 parts of polypropylene powder, 0.1-1 part of graphite powder, 0.01-0.5 part of antioxidant, and 0.5-5 parts of metal soapsalt are added and uniformly mixed in a high-speed mixer; the particle size of the graphite powder is 1000-5000 meshes; the antioxidant is a composite antioxidant composed of phenols and phosphites or thioesters in a mass ratio of 1:1. However, this method not only requires specific equipment, but also the surface of the prepared powder raw material particles is relatively rough, the particle size is not uniform enough, and the shape is irregular, which is not conducive to the formation of the sintered body and affects the performance of the formed body.

[0005] In addition, there is also a precipitation method for preparing polymer powder raw materials, such as polyamide powder. In this method, polyamide is usually dissolved in a suitable solvent, and the material is uniformly distributed in the solvent by stirring and then cooled to precipitate powder. For example, CN103374223A discloses a precipitated polymer powder based on AABB-type polyamide, which is obtained by reprecipitating the polyamide obtained by the polycondensation of diamine and dicarboxylic acid. In the method described in this patent, an alcohol solvent is used during the reprecipitation process. However, this method requires the use of a large amount of organic solvents, and both the yield and efficiency are relatively low, without environmental and economic advantages. Summary of the Invention

[0006] Aiming at the deficiencies of the above-mentioned prior art, the object of the present invention is to provide a polypropylene powder for 3D printing, its preparation method and application. The particle size distribution of this polypropylene powder is less than 2.5 and has a relatively narrow molecular weight distribution index. The polypropylene powder is in the form of regular and uniform spherical particles with a smooth surface and can be directly used for selective laser sintering 3D printing.

[0007] To achieve the above object, in the first aspect of the present invention, there is provided a polypropylene powder for 3D printing, characterized in that the polypropylene powder contains polypropylene and an antioxidant;

[0008] Based on the total weight of the polypropylene powder, the polypropylene is 99 - 99.5 parts, and the antioxidant is 0.5 - 1 part;

[0009] The molecular weight distribution index M w / M n of the polypropylene powder is 4 - 8; the particle size distribution of the polypropylene powder is less than 2.5.

[0010] In the second aspect of the present invention, there is provided a preparation method of the above polypropylene powder for 3D printing, characterized in that the method includes:

[0011] In the presence of a catalyst and an antioxidant, olefins containing propylene and ethylene and / or α-olefins are subjected to a polymerization reaction to obtain the polypropylene powder for 3D printing.

[0012] In the third aspect of the present invention, there is provided an application of the above polypropylene powder for 3D printing in selective laser sintering 3D printing.

[0013] Through the above technical solutions, the polypropylene powder for 3D printing provided by the present invention, its preparation method and application, and the polypropylene composition for 3D printing and its application obtain the following beneficial effects:

[0014] (1) The polypropylene powder for 3D printing provided by the present invention has a particle size distribution of less than 2.5 and a relatively narrow molecular weight distribution index. At the same time, the polypropylene powder is in the form of regular and uniform spherical particles with a smooth surface and can be directly used for selective laser sintering 3D printing. Compared with the commonly used crushing method in the industry, the polypropylene particles are regular and smooth, which is beneficial to the sintering process; compared with the precipitation method, the direct polymerization method reduces labor intensity and energy consumption, has a higher yield, and has the advantage of environmental protection.

[0015] (2) Due to the tiny particle size of the polypropylene powder provided by the present invention, the molded body prepared by using it for selective laser sintering 3D printing has excellent surface quality, and its mechanical properties and surface accuracy are also better than those of the polypropylene powder prepared by the prior art. Specific Embodiments

[0016] In the ranges disclosed herein, the endpoints and any values are not limited to the exact ranges or values, and these ranges or values should be understood to include values close to these ranges or values. For numerical ranges, the endpoint values of each range, between the endpoint values of each range and individual point values, and between individual point values can be combined with each other to obtain one or more new numerical ranges, and these numerical ranges should be regarded as specifically disclosed herein.

[0017] The first aspect of the present invention provides a polypropylene powder for 3D printing, characterized in that the polypropylene powder comprises polypropylene and an antioxidant;

[0018] Based on the total weight of the polypropylene powder, the polypropylene is 99 - 99.5 parts, and the antioxidant is 0.5 - 1 part;

[0019] The molecular weight distribution index M w / M n of the polypropylene powder is 4 - 8; the particle size distribution of the polypropylene powder is less than 2.5.

[0020] In the present invention, the polypropylene powder for 3D printing has a particle size distribution of less than 2.5 and a relatively narrow molecular weight distribution index. At the same time, the polypropylene powder is in the form of regular and uniform spherical particles with a smooth surface and can be directly used for selective laser sintering 3D printing. Compared with the commonly used crushing method in the industry, the polypropylene particles are regular and smooth, which is beneficial to the sintering process; compared with the precipitation method, the direct polymerization method reduces labor intensity and energy consumption, has a higher yield, and has the advantage of environmental protection.

[0021] In the present invention, the molecular weight distribution index of the polypropylene powder is measured by GPC. In the present invention, the particle size distribution of the polypropylene powder is obtained according to (D90 - D10) / D50.

[0022] Furthermore, the particle size distribution of the polypropylene powder is less than 2; the molecular weight distribution index M w / M n is 4.5 - 6.

[0023] According to the present invention, the average particle diameter D50 of the polypropylene powder is 10 - 500 μm, preferably 50 - 200 μm.

[0024] In the present invention, the average particle diameter and particle size distribution of the polypropylene powder are measured by a laser particle size analyzer such as the Master Sizer 2000 laser particle size analyzer (manufactured by Malvern Instruments Ltd).

[0025] According to the present invention, the melting point T m of the polypropylene powder is 120 - 170 °C.

[0026] Furthermore, the melting point T m of the polypropylene powder is 129 - 160 °C.

[0027] According to the present invention, the crystallization temperature T c of the polypropylene powder is 80 - 130 °C.

[0028] Furthermore, the crystallization temperature T c of the polypropylene powder is 95 - 120 °C.

[0029] In the present invention, when the melting point T m and crystallization temperature T c of the polypropylene powder satisfy the above ranges, it can ensure that the polypropylene powder has a wide processing window.

[0030] In the present invention, the melting point T m and crystallization temperature T c of the polypropylene powder are measured by DSC.

[0031] According to the present invention, at 230 °C and a load of 2.16 kg, the melt flow rate MFR of the polypropylene powder is 1 - 1000 g / 10 min.

[0032] In the present invention, when the melt flow rate of the polypropylene powder satisfies the above range, the polypropylene powder has appropriate fluidity, and can ensure excellent moldability of the product while ensuring the density of the product.

[0033] In the present invention, the melt flow rate of the polypropylene powder is measured by the method specified in ISO1133 - 1 - 2011.

[0034] Further, the melt flow rate MFR of the polypropylene powder is 1-399 g / 10 min, preferably 10-50 g / 10 min.

[0035] According to the present invention, the bulk density of the polypropylene powder is 0.3-0.5 g / cm 3 .

[0036] In the present invention, when the bulk density of the polypropylene powder satisfies the above range, the polypropylene powder is easy to spread, thereby improving the surface finish of the polypropylene product.

[0037] In the present invention, the bulk density of the polyolefin powder is measured by the method specified in GB / T 1636-2008.

[0038] Further, the bulk density of the polypropylene powder is 0.35-0.45 g / cm 3 .

[0039] According to the present invention, the polypropylene is a copolymer of propylene with ethylene and / or α-olefin.

[0040] In the present invention, the α-olefin can be a commonly used α-olefin in the art, such as α-butene, α-pentene, etc.

[0041] According to the present invention, based on the total weight of the polypropylene, the content of the structural unit provided by the ethylene and / or α-olefin is 1-5 wt%.

[0042] Further, based on the total weight of the polypropylene, the content of the structural unit provided by the ethylene and / or α-olefin is 1.5-3.5 wt%.

[0043] According to the present invention, the antioxidant is selected from at least one of antioxidant 1010, antioxidant 168 and antioxidant 1076.

[0044] The second aspect of the present invention provides a method for preparing the above-mentioned polypropylene powder for 3D printing, which is characterized in that the method includes:

[0045] In the presence of a catalyst and an antioxidant, polymerize an olefin containing propylene and ethylene and / or α-olefin to obtain the polypropylene powder for 3D printing.

[0046] According to the present invention, the catalyst includes a spherical carrier.

[0047] According to the present invention, the average particle diameter of the spherical carrier is 2-100 microns; the particle size distribution is less than 2.

[0048] In the present invention, in the presence of a catalyst comprising the above-mentioned spherical carrier with an average particle diameter and particle size distribution, polypropylene powder with a good spherical morphology, uniform particles, a smooth surface, and a particle size distribution between 10 μm and 500 μm can be prepared, and this polypropylene powder can be directly used for selective laser sintering 3D printing.

[0049] In the present invention, the average particle diameter refers to D50.

[0050] In the present invention, the size of the particle size distribution is obtained according to (D90 - D10) / D50.

[0051] In the present invention, the average particle diameter and particle size distribution of the catalyst carrier are measured using a laser particle size analyzer such as the Master Sizer 2000 laser particle size analyzer (manufactured by Malvern Instruments Ltd).

[0052] Furthermore, the average particle diameter of the spherical carrier is 2 - 19 microns, and the particle size distribution is 0.6 - 1.6.

[0053] According to the present invention, the spherical carrier has the structure shown in formula (1);

[0054] Formula (1)

[0055] Among them, in formula (1), R1 is selected from C 1-10 alkyl;

[0056] R2 and R3 are each independently selected from H, C 1-10 alkyl and C 1-10 haloalkyl substituted by 1 - 10 halogen atoms;

[0057] R4 is selected from C 1-10 haloalkyl substituted by at least one halogen atom and C 6-20 haloaryl substituted by at least one halogen atom;

[0058] R5 is selected from C 1-5 alkyl;

[0059] X is selected from fluorine, chlorine, bromine, and iodine;

[0060] m is 0.1 - 1.9, n is 0.1 - 1.9, and m + n = 2; 0 < q < 0.2; 0 < a < 0.1.

[0061] In the present invention, in the presence of a catalyst comprising the spherical carrier represented by the above formula (1), polypropylene powder with a regular and uniform spherical appearance and a smooth surface can be directly polymerized, and this polypropylene powder can be directly used for selective laser sintering 3D printing.

[0062] In the present invention, in formula (1), The part represents .

[0063] In the present invention, R1 is selected from C 1-10 alkyl groups, and the R1 is a straight-chain, branched-chain or cyclic alkyl group, including but not limited to methyl, ethyl, n-propyl, isopropyl, cyclopropyl, n-butyl, sec-butyl, isobutyl, tert-butyl, cyclobutyl, n-pentyl, isopentyl, neopentyl, cyclopentyl, n-hexyl, isohexyl, cyclohexyl, 1-ethylpropyl, 2-methylbutyl, 3-methylbutyl, 2,2-dimethylpropyl, etc.

[0064] In this text, the alkyl substitution groups for R1 have a similar definition as above, only the number of carbon atoms is different, and the present invention will not describe them in detail hereinafter.

[0065] In order to obtain a spherical carrier with better performance, preferably, R1 is selected from C 1-8 alkyl; more preferably, R1 is selected from C 1-6 alkyl.

[0066] In the present invention, R2 and R3 are each independently selected from H, C 1-10 alkyl and C 1-10 haloalkyl substituted by 1-10 halogen atoms.

[0067] When the R2 and R3 are selected from C 1-10 alkyl and C 1-10 haloalkyl substituted by 1-10 halogen atoms, the alkyl is a straight-chain or branched-chain group, and the C 1-10 alkyl includes, for example, but not limited to methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, isobutyl, tert-butyl, n-pentyl, isopentyl, neopentyl, n-hexyl, isohexyl, 1-ethylpropyl, 2-methylbutyl, 3-methylbutyl, 2,2-dimethylpropyl, etc. The haloalkyl is a straight-chain or branched-chain group, and the C 1-10 haloalkyl substituted by 1-10 halogen atoms refers to C 1-10A group formed by substituting 1 to 10 hydrogen atoms in the alkyl group with halogen atoms, where multiple hydrogen atoms on the same carbon atom can be substituted by halogen atoms, or hydrogen atoms on different carbon atoms can be substituted; when multiple halogen atoms are substituted, the halogen atoms can be the same or different, and the halogen atoms are fluorine, chlorine, bromine or iodine atoms. For example, but not limited to, -CF3, -CH2CF3, -CH2CF2H, -CF2CF3, -CF2CH2CF2H, -CH2CF2CF2H, -CH2CH2CH2Cl, -CH2CH2CH2Br, etc.

[0068] In this text, the alkyl substitution groups and haloalkyl substitution groups for R2 and R3 have similar definitions as above, only differing in the number of carbon atoms, and will not be described in detail later in the present invention.

[0069] To obtain a spherical carrier with better performance, preferably, R2 and R3 each independently selected from H, C 1-5 alkyl group and C substituted by 1 - 10 halogen atoms 1-5 haloalkyl group.

[0070] In the present invention, R4 is selected from a C 1-10 haloalkyl group substituted by at least one halogen atom and a C 6-20 haloaryl group substituted by at least one halogen atom. The C 1-10 haloalkyl group substituted by at least one halogen atom and the C 6-20 haloaryl group substituted by at least one halogen atom refer to groups formed by substituting at least one hydrogen atom in a C 1-10 alkyl group, C 6-20 aryl group with halogen atoms, and the halogen atoms are fluorine, chlorine, bromine or iodine atoms. Among them, the C 1-10 haloalkyl group can be a straight-chain, branched-chain or cyclic group, for example, including but not limited to CF3, -CH2CF3, -CH2CF2H, -CF2CF3, -CF2CH2CF2H, -CH2CF2CF2H, -CH2CH2CH2Cl, -CH2CH2CH2Br, etc. The C 6-20 haloaryl group refers to a haloaryl group with 6 - 20 carbon atoms.

[0071] In this text, the substitution groups for R4 have similar definitions as above, only differing in the number of carbon atoms, and will not be described in detail later in the present invention.

[0072] To obtain a spherical carrier with better performance, preferably, R4 is selected from a C 1-10 haloalkyl group substituted by at least two halogen atoms and a C substituted by at least two halogen atoms6-20 a haloaromatic group, and the halogen atom is preferably selected from at least one of a chlorine atom, a bromine atom, and an iodine atom.

[0073] In the present invention, the substitution by at least two halogen atoms means that at least two hydrogen atoms in an alkyl group of C 1-10 and an aromatic group of C 6-20 are substituted by halogen atoms. The hydrogen atoms can be hydrogen atoms on one carbon or hydrogen atoms on different carbons. The halogen atoms can be the same or different.

[0074] In the present invention, R5 is selected from an alkyl group of C 1-5 The alkyl group of C 1-5 refers to an alkyl group having 1 - 5 carbon atoms, such as, including but not limited to, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, n-pentyl, isopentyl, etc.

[0075] In this article, the substitution groups regarding R5 have similar definitions as above, only with different numbers of carbon atoms, and will not be described in detail later in the present invention.

[0076] To obtain a spherical carrier with better performance, preferably, R5 is selected from an alkyl group of C 1-2

[0077] To obtain a spherical carrier with better performance, preferably, X is selected from chlorine and bromine.

[0078] According to the present invention, the volume ratio of the propylene to the ethylene and / or α-olefin is 12.7 - 80:1.

[0079] Further, the volume ratio of the propylene to the ethylene and / or α-olefin is 20 - 50:1.

[0080] According to the present invention, the dosage of the antioxidant is 0.5 - 1 wt% relative to the total amount of the olefins used.

[0081] Further, the dosage of the antioxidant is 0.55 - 0.95 wt% relative to the total amount of the olefins used.

[0082] According to the present invention, the antioxidant is selected from at least one of antioxidant 1010, antioxidant 168, and antioxidant 1076.

[0083] ​In the present invention, in order to obtain a catalyst suitable for use in olefin polymerization, especially propylene polymerization, preferably, the catalyst contains a spherical carrier, a titanium halide compound, and an electron donor compound. Preferably, the titanium halide is selected from at least one of titanium tetrachloride, titanium tetrabromide, titanium tetraiodide, tetra-n-butoxytitanium, tetraethoxytitanium, monochloro-tri-n-butoxytitanium, dichloro-di-n-butoxytitanium, trichloro-n-butoxytitanium, monochloro-triethoxytitanium, dichloro-diethoxytitanium, trichloro-ethoxytitanium, and titanium trichloride. Preferably, the electron donor compound is selected from at least one of diisobutyl phthalate, glycol carboxylic acid ester, and phosphate ester. At the same time, the present invention has no special limitation on the content of each component in the catalyst, and those skilled in the art can make reasonable adjustment and design according to actual needs.

[0084] The present invention has no special limitation on the preparation method of the catalyst, and it can be prepared by using the existing methods for preparing olefin polymerization catalysts in the art. A specific operation process is listed in the examples hereinafter of the present invention, and those skilled in the art should not understand it as a limitation to the present invention.

[0085] In a specific embodiment of the present invention, the spherical carrier is prepared according to the following steps:

[0086] (1) Component A is first contacted and emulsified successively to obtain a first product. Component A contains magnesium halide of the general formula MgXY and a first alcohol compound of the general formula R1OH;

[0087] (2) The first product is secondarily contacted with component B to obtain a second product. Component B contains an ethylene oxide compound having the structure shown in formula (2);

[0088] (3) The second product is tertiarily contacted with component C to obtain a third product. Component C contains a halogenated alcohol of the general formula R4OH and a second alcohol compound of the general formula R5OH;

[0089] (4) The third product is spray-dried;

[0090] Formula (2),

[0091] wherein, in formula R1OH, R1 is selected from C 1-10 alkyl;

[0092] In formula (2), R2 and R3 each independently selected from H, C 1-10 alkyl and C 1-10 haloalkyl substituted by 1-10 halogen atoms;

[0093] In formula R4OH, R4 is selected from C 1-10haloalkyl and C substituted by at least one halogen atom 6-20 haloaryl;

[0094] In the formula R5OH, R5 is selected from C 1-5 alkyl;

[0095] In the formula MgXY, X is selected from fluorine, chlorine, bromine and iodine; Y is selected from fluorine, chlorine, bromine, iodine, C 1-6 alkyl, C 1-6 alkoxy, C 6-14 aryl and C 6-14 aryloxy;

[0096] The dosages of the component A, the component B and the component C are such that the obtained spherical carrier has the structure shown in formula (1):

[0097] Formula (1),

[0098] In formula (1), m is 0.1 - 1.9, n is 0.1 - 1.9, and m + n = 2; 0 < q < 0.2; 0 < a < 0.1;

[0099] Wherein, in step (3), relative to 1 mol of the magnesium halide, the dosage of the haloalcohol is 0.05 - 6.5 mol, and the dosage of the second alcohol compound is 5 - 100 mol.

[0100] In the present invention, in the preparation method of the spherical carrier, the definitions of the substituents of R1, R2, R3, R4 and R5 are the same as those of the spherical carrier described above in the present invention, and will not be elaborated herein one by one.

[0101] In the present invention, in the formula MgXY, when Y is selected from C 1-6 alkyl, C 1-6 alkoxy, the alkyl and the alkoxy are straight-chain or branched-chain alkyl and alkoxy groups, and the C 1-6 alkyl refers to an alkyl group having 1 - 6 carbon atoms, such as including but not limited to methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, n-pentyl, isopentyl, etc.; the C 1-6 alkoxy refers to an alkoxy group having 1 - 6 carbon atoms, such as including but not limited to methoxy, ethoxy, n-propoxy, isopropoxy, n-butoxy, sec-butoxy, isobutoxy, tert-butoxy, n-pentyloxy, isopentyloxy, etc.

[0102] The C 6-14 aryl refers to an aryl group having 6 - 14 carbon atoms, such as including but not limited to phenyl, o-tolyl, m-tolyl, p-tolyl, o-ethylphenyl, m-ethylphenyl, p-ethylphenyl, naphthyl, etc.

[0103] The aryloxy group of said C 6-14 refers to an aryloxy group having 6-14 carbon atoms, such as, including but not limited to, phenoxy, naphthyloxy, o-methylphenoxy, o-ethylphenoxy, m-methylphenoxy, etc.

[0104] In this text, in the formula MgXY, the substituent groups for Y such as alkyl, alkoxy, aryl and aryloxy have similar definitions as above, only with different numbers of carbon atoms, and will not be described in detail later in the present invention.

[0105] According to a preferred specific embodiment of the present invention, in the formula MgXY, X is selected from chlorine and bromine, and Y is selected from chlorine, bromine, C 1-5 alkyl group of 1-5 alkoxy group of 6-10 aryl group of 6-10 aryloxy group of

[0106] In order to obtain spherical carriers with smaller particle size and better performance, more preferably, the magnesium halide is selected from at least one of magnesium chloride, magnesium bromide, magnesium phenoxychloride, magnesium isopropoxychloride and magnesium n-butoxychloride, and even more preferably magnesium chloride.

[0107] According to another preferred specific embodiment of the present invention, in the formula R1OH, R1 is selected from C 1-8 alkyl group of

[0108] In order to obtain spherical carriers with smaller particle size, more uniform particle size distribution and better performance, more preferably, the first alcohol compound is selected from at least one of ethanol, propanol, isopropanol, n-butanol, isobutanol, pentanol, isopentanol, n-hexanol, n-octanol and 2-ethylhexanol.

[0109] According to yet another preferred specific embodiment of the present invention, in the formula (2), R2 and R3 each independently selected from H, C 1-5 alkyl group of 1-5 haloalkyl group of

[0110] In order to obtain spherical carriers with smaller particle size, more uniform particle size distribution and better performance, more preferably, the ethylene oxide compound is selected from at least one of ethylene oxide, propylene oxide, butylene oxide, epichlorohydrin, epichlorobutane, epibromopropane and epibromobutane.

[0111] According to the present invention, the haloalcohol may be a monohaloalcohol or a polyhaloalcohol, preferably a chloroalcohol, a bromoalcohol or an iodoalcohol, such as 2,2,2-trichloroethanol, 2,2-dichloroethanol, 2-chloroethanol, 3-chloro-1-propanol, 6-chloro-1-hexanol, 3-bromo-1-propanol, 5-chloro-1-pentanol, 4-chloro-1-butanol, 2-chlorocyclohexanol, 1,2-dichloroethanol, 1,3-dichloropropanol, 1,4-dichlorobutanol or 2-iodoethanol, etc.

[0112] However, in order to obtain spherical carriers with better performance, according to another preferred specific embodiment of the present invention, in the formula R4OH, R4 is selected from a haloalkyl group of C substituted by at least two halogen atoms and a haloaryl group of C substituted by at least two halogen atoms, and the halogen atom is selected from at least one of a chlorine atom, a bromine atom and an iodine atom. 1-10 substituted by at least two halogen atoms and C 6-20 substituted by at least two halogen atoms, and the halogen atom is selected from at least one of a chlorine atom, a bromine atom and an iodine atom.

[0113] Preferably, the haloalcohol is selected from at least one of 2,2,2-trichloroethanol, 2,2-dichloroethanol, 1,2-dichloroethanol, 1,3-dichloropropanol and 1,4-dichlorobutanol.

[0114] According to the present invention, the second alcohol compound is selected from at least one of alcohol compounds of C, such as ethanol, methanol, n-propanol, isopropanol, n-butanol or isobutanol. However, in order to obtain spherical carriers with better performance, according to another preferred specific embodiment of the present invention, in the formula R5OH, R5 is selected from an alkyl group of C, that is, the second alcohol compound is methanol and / or ethanol. 1-5 substituted by at least two halogen atoms and C 1-2 substituted by at least two halogen atoms, and the halogen atom is selected from at least one of a chlorine atom, a bromine atom and an iodine atom.

[0115] According to the present invention, the inventors found that when the dosages of the haloalcohol compound and the alcohol compound are too large, the obtained spherical carriers agglomerate and subsequent operations cannot be carried out.

[0116] Preferably, relative to 1 mol of the magnesium halide, the dosage of the first alcohol compound is 1-30 mol, and the dosage of the ethylene oxide compound is 1-10 mol.

[0117] More preferably, relative to 1 mol of the magnesium halide, the dosage of the first alcohol compound is 6-22 mol, the dosage of the ethylene oxide compound is 2-6 mol, the dosage of the haloalcohol is 1-5 mol, and the dosage of the second alcohol compound is 8-80 mol, more preferably 31-50 mol.

[0118] In the present invention, it should be noted that the trace water carried in each of the above reactants will also participate in the reaction for forming the spherical carrier. Therefore, the prepared spherical carrier may contain trace water from the reaction raw materials and the reaction medium, which should not be construed as a limitation to the present invention by those skilled in the art.

[0119] Preferably, in step (1), the first contact is carried out under stirring, and the conditions for the first contact include: the temperature is 80 - 120 °C, and the time is 0.5 - 5 h.

[0120] More preferably, in step (1), the conditions for the first contact include: the temperature is 80 - 100 °C, and the time is 0.5 - 3 h.

[0121] In step (1), the present invention has no particular limitation on the specific operation method of the emulsification, and it can be carried out by methods well known to those skilled in the art. For example, low-speed shearing or high-speed shearing can be used for emulsification. Preferably, when low-speed shearing is used, the stirring rate of the low-speed shearing is 400 - 800 rpm. The method of high-speed shearing is well known to those skilled in the art. For example, the high-speed stirring speed disclosed in CN1330086A can be used. In addition, the emulsification operation can also be carried out with reference to the methods disclosed in the following patent applications. For example, the solution containing a liquid magnesium halide compound is rotationally dispersed in a high-gravity bed (the rotation speed is 100 - 3000 rpm) as disclosed in CN1580136A; or the solution containing a liquid magnesium halide adduct is output at a speed of 1500 - 8000 rpm in an emulsifier as disclosed in CN1463990A; or the solution containing a liquid magnesium halide adduct is emulsified by a spray method as disclosed in US6020279A.

[0122] Preferably, in step (2), the conditions for the second contact include: the temperature is 50 - 120 °C, and the time is 20 - 60 min.

[0123] More preferably, in step (2), the conditions for the second contact include: the temperature is 80 - 100 °C, and the time is 20 - 50 min.

[0124] According to a preferred specific embodiment of the present invention, in step (3), it further includes washing the second product with an inert solvent and then carrying out the third contact with each component in component C. Preferably, the inert solvent is selected from at least one of pentane, hexane, heptane, petroleum ether, and gasoline.

[0125] The present invention has no particular limitation on the specific conditions of the third contact in step (3), as long as the component C and the second product can be sufficiently contacted to form a fluid. However, in order to obtain a catalyst support with better performance, preferably, in step (3), the conditions of the third contact include: carried out under stirring conditions, the temperature is 0-120°C, and the time is 0.5-6 h.

[0126] The present invention has no particular limitation on the specific manner of the third contact in step (3). The haloalcohol and the second alcohol compound can be mixed and contacted with the second component synchronously, or the haloalcohol and the second alcohol compound can be contacted with the second component separately and sequentially.

[0127] In the present invention, the conditions of the spray drying can adopt the existing conditions that can form a spherical support for olefin polymerization. However, in order to obtain a spherical support with better performance, according to a preferred specific embodiment of the present invention, the spray drying is carried out in a spray dryer having an atomizing nozzle. The atomizing nozzle includes a material conduit and a nozzle head. The third product is introduced into the nozzle head through the material conduit and is sprayed through the nozzle head into the tower body of the spray dryer containing an inert medium for solidification. Preferably, the temperature of the third product in the material conduit is between 0°C and 80°C, and the temperature of the third product in the nozzle head is 80-180°C; more preferably, the temperature of the third product in the nozzle head is 120-180°C.

[0128] In the present invention, in step (4), preferably, the conditions of the spray drying include: the temperature is 60-200°C, more preferably 90-150°C. In the present invention, the temperature of the spray drying refers to the temperature of the inert medium in the spray dryer.

[0129] In the present invention, the inert medium can include a protective gas medium and / or an inert liquid medium. There is no particular limitation on the type of the protective gas medium. For example, it can be nitrogen or an inert gas medium such as helium, or other suitable gases such as carbon dioxide, etc.; the inert liquid medium is various liquid media commonly used in the art that do not chemically react with the reactants and reaction products. Preferably, the inert liquid medium is silicone oil and / or an inert liquid hydrocarbon solvent; more preferably, the inert liquid medium is selected from at least one of kerosene, paraffin oil, petrolatum oil, white oil, methyl silicone oil, ethyl silicone oil, methyl ethyl silicone oil, phenyl silicone oil, and methyl phenyl silicone oil, and still more preferably white oil.

[0130] In the present invention, the amount of the inert liquid medium in the spray dryer can be selected according to the amount of magnesium halide of the general formula MgXY, preferably 0.8-10 L, more preferably 2-8 L.

[0131] In the method for preparing the spherical carrier according to the present invention, post-treatment means conventional in the art, such as solid-liquid separation, washing, drying, etc., are also included, and the present invention has no particular limitation thereto. The solid-liquid separation can adopt various existing methods capable of separating the solid phase from the liquid phase, such as suction filtration, pressure filtration or centrifugal separation, etc. Preferably, the method for solid-liquid separation is pressure filtration. The present invention has no particular limitation on the conditions of pressure filtration, as long as the separation of the solid phase from the liquid phase can be achieved as fully as possible. The washing can be carried out by washing the obtained solid-phase product with methods well-known to those skilled in the art. For example, the obtained solid-phase product can be washed with an inert hydrocarbon solvent (such as pentane, hexane, heptane, petroleum ether and gasoline). The present invention has no particular limitation on the specific conditions of the drying. For example, the drying temperature can be 20-70°C, the drying time can be 0.5-10 h, and the drying can be carried out under normal pressure or reduced pressure conditions.

[0132] The inventors have found that by using specific types and amounts of alcohol compounds and haloalcohol compounds in combination with components such as magnesium halide and ethylene oxide compounds, and at the same time matching a specific spray drying method, a spherical carrier with a novel composition and good particle morphology can be obtained. The spherical carrier basically has no abnormal particles; and no surfactant needs to be added during the preparation process, and the process is stable.

[0133] In particular, the method provided by the present invention can prepare spherical carriers with very small particle sizes, greatly expanding the range of preparable particle sizes of the carriers; and when the catalyst prepared from the spherical carrier is used for olefin polymerization, the hydrogen response sensitivity is relatively high.

[0134] The third aspect of the present invention provides a polypropylene powder for 3D printing prepared by the above preparation method.

[0135] In the present invention, the polypropylene powder contains polypropylene and an antioxidant;

[0136] Based on the total weight of the polypropylene powder, the polypropylene is 99-99.5 parts, and the antioxidant is 0.5-1 part;

[0137] The molecular weight distribution index M w / M n is 4-8, preferably 4.5-6; the particle size distribution of the polypropylene powder is less than 2.5, preferably less than 2.

[0138] In the present invention, the average particle diameter D50 of the polypropylene powder is 10-500 μm, preferably 50-200 μm.

[0139] In the present invention, the melting point T mis 120 - 170 °C, preferably 129 - 160 °C.

[0140] In the present invention, the crystallization temperature T of the polypropylene powder c is 80 - 130 °C, preferably 95 - 120 °C.

[0141] In the present invention, at 230 °C and a load of 2.16 kg, the melt flow rate MFR of the polypropylene powder is 1 - 1000 g / 10 min; preferably 1 - 399 g / 10 min, more preferably 10 - 50 g / 10 min.

[0142] In the present invention, the bulk density of the polypropylene powder is 0.3 - 0.5 g / cm 3 , preferably 0.35 - 0.45 g / cm 3 .

[0143] In the present invention, the polypropylene is a copolymer of propylene with ethylene and / or α-olefin.

[0144] In the present invention, the α-olefin can be a commonly used α-olefin in the art, such as α-butene, α-pentene, etc.

[0145] In the present invention, based on the total weight of the polypropylene, the content of the structural unit provided by the ethylene and / or α-olefin is 1 - 5 wt%, preferably 1.5 - 3.5 wt%.

[0146] In the present invention, the antioxidant is selected from at least one of antioxidant 1010, antioxidant 168, and antioxidant 1076.

[0147] The fourth aspect of the present invention provides the application of the above polypropylene powder for 3D printing in selective laser sintering 3D printing.

[0148] The present invention will be described in detail below through examples. In the following examples,

[0149] 1. Average particle diameter and particle size distribution of the catalyst support: Measured by a Masters Sizer 2000 particle size analyzer manufactured by Malvern Instruments;

[0150] 2. Morphology of the catalyst support: Observed by an XL-30 type field emission electron microscope produced by FEI Company of the United States;

[0151] 3. Structure and Composition of Catalyst Support: Obtained by performing 1H-NMR testing on the support using an AVANCE 300 nuclear magnetic resonance spectrometer from Bruker, Switzerland, and by testing the support using a PY-2020iD pyrolyzer from Fronteerlab, a TraceGC Ultra chromatograph from Thermo Fisher, and a DSQ II mass spectrometer;

[0152] 4. Catalyst Activity: Evaluated by the ratio of the weight of the product obtained after polymerization to the weight of the catalyst used;

[0153] 5. Bulk Density of Polyolefin Powder: Determined by the method specified in GB / T 1636-2008;

[0154] 6. Melt Flow Rate Index of Polyolefin Powder: Measured according to ISO1133 at 230 °C under a load of 2.16 kg;

[0155] 7. Test Method for Molecular Weight Distribution Index M w / M n of Polypropylene Powder: Determined by the method specified in GB / T 36214-2018;

[0156] 8. Test Method for Melting Point T m and Crystallization Temperature T c of Polypropylene Powder: On a Perkin Elmer Pyris 1 analyzer, each sample is heated from -100 °C to 250 °C and undergoes two heating scans at a heating rate of 10 °C / min;

[0157] In the following examples, unless otherwise specified, emulsification is carried out under stirring at 600 rpm during the preparation of the catalyst support.

[0158] In the following examples and comparative examples, the materials used are as follows:

[0159] In the following examples, unless otherwise specified, the raw materials used are all commercially available products.

[0160] 1,3-dichloropropanol was purchased from J&K Scientific Ltd.;

[0161] Epichlorohydrin was purchased from J&K Scientific Ltd.;

[0162] Diisobutyl phthalate was purchased from J&K Scientific Ltd.;

[0163] Titanium tetrachloride was purchased from J&K Scientific Ltd.;

[0164] Triethylaluminum was purchased from J&K Scientific Ltd.;

[0165] Methylcyclohexyldimethoxysilane was purchased from J&K Scientific Ltd.;

[0166] Antioxidant 1010 was produced by BASF Ciba of Germany;

[0167] The polypropylene was B4808 from Sinopec Yanshan Petrochemical Company, with a melting point of 138 °C and a melt index of 11.1 g / 10 min;

[0168] Xylene was purchased from Aladdin.

[0169] Preparation Example 1 of Catalyst Microsphere Carrier

[0170] (1) In a 0.6 L reactor, 0.08 mol of magnesium chloride and 1.7 mol of ethanol (the first alcohol compound) were added. The temperature was raised to 90 °C under stirring, and the first contact was carried out at a constant temperature for 1 h, and then emulsification was carried out to obtain the first product;

[0171] (2) The first product was subjected to a second contact with 0.48 mol of epichlorohydrin to obtain a second product. The conditions of the second contact included: temperature of 90 °C and time of 30 min;

[0172] (3) After the second product was pressure-filtered, it was fully mixed and stirred with 2.5 mol of ethanol (the second alcohol compound) and 0.35 mol of 1,3-dichloropropanol (halohydrin) for the third contact to form a fluid, and a third product was obtained;

[0173] (4) The third product was sprayed into the circulating nitrogen at 100 °C in a spray tower of a spray machine B-290 using a spray machine equipped with a nozzle head and a material conduit for spray drying. The temperature of the third product in the material conduit was 15 °C, and the temperature in the nozzle head was 120 °C to obtain the spherical carrier Z1.

[0174] After testing, the structure and composition of the obtained catalyst spherical carrier Z1 were as follows:

[0175]

[0176] After testing, the average particle diameter (D50) of the catalyst spherical carrier Z1 was 4 μm, and the particle size distribution ((D90 - D10) / D50) was 0.9.

[0177] After observation, the particle morphology of the catalyst spherical carrier Z1 was relatively regular, the surface was smooth, basically all spherical, the particle size distribution was relatively concentrated, and there were basically no abnormal-shaped particles.

[0178] During the preparation of the catalyst spherical carrier Z1, no blockage occurred at the nozzle head of the spray machine, and a total of 11.8 g of carrier Z1 was obtained.

[0179] Preparation Example 2 of Catalyst Microsphere Carrier

[0180] (1) In a 0.6 L reactor, 0.08 mol of magnesium chloride and 1.4 mol of ethanol (the first alcohol compound) were added. While stirring, the temperature was raised to 90 °C, and the first contact was carried out with constant temperature reaction for 1.5 h. Then, through emulsification, the first product was obtained;

[0181] (2) The first product was subjected to a second contact with 0.35 mol of epichlorohydrin to obtain a second product. The conditions for the second contact included: temperature of 90 °C and time of 30 min;

[0182] (3) After the second product was pressure-filtered, it was fully mixed and stirred with 2.5 mol of ethanol (the second alcohol compound) and 0.25 mol of 1,3-dichloropropanol (halohydrin) for a third contact to form a fluid, and a third product was obtained;

[0183] (4) The third product was sprayed into the circulating nitrogen at 100 °C in a spray tower of a spray machine B-290 using a spray machine equipped with a nozzle head and a material conduit for spray drying. The temperature of the third product in the material conduit was 15 °C, and the temperature in the nozzle head was 120 °C, to obtain the catalyst spherical carrier Z2.

[0184] After testing, the structure and composition of the obtained catalyst spherical carrier Z2 were as follows:

[0185]

[0186] After testing, the average particle diameter (D50) of the catalyst spherical carrier Z2 was 4 μm, and the particle size distribution ((D90 - D10) / D50) was 0.8.

[0187] After observation, the particle morphology of the spherical carrier Z2 for olefin polymerization was relatively regular, the surface was smooth, and it was basically spherical. The particle size distribution was relatively concentrated, and there were basically no abnormal particles.

[0188] During the process of preparing the catalyst spherical carrier Z2, no blockage occurred at the nozzle head of the spray machine, and a total of 11.9 g of the catalyst spherical carrier Z2 was obtained.

[0189] Preparation Example 3 of Catalyst Microsphere Carrier

[0190] (1) In a 0.6 L reactor, 0.08 mol of magnesium chloride and 1.4 mol of ethanol (the first alcohol compound) were added. While stirring, the temperature was raised to 90 °C, and the first contact was carried out with constant temperature reaction for 1.5 h. Then, emulsification was carried out to obtain the first product;

[0191] (2) The first product is brought into second contact with 0.35 mol of epichlorohydrin to obtain a second product. The conditions of the second contact include: a temperature of 90 °C and a time of 30 min;

[0192] (3) After pressure filtration of the second product, it is stirred with 2.5 mol of ethanol (the second alcohol compound) and 0.1 mol of 1,3-dichloropropanol (halohydrin) until third contact occurs to form a fluid, obtaining a third product;

[0193] (4) The third product is sprayed into the circulating nitrogen at 100 °C in a spray tower of a spray machine B-290 using a spray machine equipped with a nozzle head and a material conduit. The temperature of the third product in the material conduit is 15 °C, and the temperature in the nozzle head is 120 °C, obtaining a spherical carrier Z3.

[0194] After testing, the structure and composition of the obtained catalyst spherical carrier Z3 are as follows:

[0195]

[0196] After testing, the average particle diameter (D50) of the catalyst spherical carrier Z3 is 5 microns, and the particle size distribution ((D90 - D10) / D50) is 0.8.

[0197] Upon observation, the particle morphology of the catalyst spherical carrier Z3 is relatively regular, the surface is smooth, and it is basically spherical. The particle size distribution is relatively concentrated, and there are basically no abnormal-shaped particles.

[0198] During the preparation of the catalyst spherical carrier Z3, no blockage occurred at the nozzle head of the spray machine, and a total of 12.0 g of the catalyst spherical carrier Z3 was obtained.

[0199] Catalyst microsphere carrier Comparative Example 1

[0200] (1) In a 0.6 L reaction kettle, 0.08 mol of magnesium chloride and 1.4 mol of ethanol are added. The temperature is raised to 90 °C under stirring, and the reaction is carried out at a constant temperature for 1.5 h. Then, 0.35 mol of epichlorohydrin is added, and the reaction is carried out at 90 °C for 30 min to obtain a fluid mixture;

[0201] (2) The fluid mixture is sprayed into the circulating nitrogen at 100 °C using a spray machine equipped with a nozzle head and a material conduit. The temperature of the fluid mixture in the material conduit is 90 °C, and the temperature in the nozzle head is 120 °C, obtaining a catalyst carrier DZ1 for olefin polymerization.

[0202] During the spraying process, the fluid mixture obtained in step (1) is extremely prone to precipitation, which easily causes the spray drying to not proceed normally and easily causes the nozzle to become blocked.

[0203] The average particle diameter (D50) of the catalyst carrier DZ1 for olefin polymerization is 15 μm, and the particle size distribution ((D90 - D10) / D50) is 1.3.

[0204] Catalyst microsphere carrier Comparative Example 2

[0205] (1) In a 0.6 L reactor, 0.08 mol of magnesium chloride and 1.7 mol of ethanol were added. The temperature was raised to 90 °C under stirring. After reacting at a constant temperature for 1 h, 0.48 mol of epichlorohydrin was added and reacted at 90 °C for 30 min to obtain a first product;

[0206] (2) After filtering the first product by pressure filtration, 2.5 mol of ethanol was added and stirred until a fluid mixture was formed;

[0207] (3) The fluid mixture was sprayed into circulating nitrogen at 100 °C using a sprayer equipped with a nozzle head and a material conduit. The temperature of the third product in the material conduit was 15 °C, and the temperature in the nozzle head was 120 °C to obtain the catalyst carrier DZ2 for olefin polymerization.

[0208] The average particle diameter (D50) of the catalyst carrier DZ2 for olefin polymerization is 3 μm, and the particle size distribution ((D90 - D10) / D50) is 0.8.

[0209] Catalyst microsphere carrier Comparative Example 3

[0210] The catalyst spherical carrier was prepared in a manner similar to that of Example 1, except that: in step (3), the second alcohol compound was not used, and only the halogenated alcohol (1,3 - dichloropropanol) was used to fully mix and stir with the second product for the third contact, and the amount of the halogenated alcohol used was the same as that in Example 1 to obtain the catalyst carrier DZ3.

[0211] During the preparation of the catalyst carrier DZ3, the carrier agglomerated and subsequent operations could not be carried out.

[0212] Polypropylene powder preparation example 1

[0213] (1) Prepare a catalyst for olefin polymerization

[0214] In a 300 mL reaction flask, 100 mL of titanium tetrachloride was added, and it was cooled to -20 °C. 8 g of the catalyst spherical carrier Z1 obtained from Preparation Example 1 of the catalyst microsphere carrier was added thereto, and it was stirred at -20 °C for 30 min. Then, the temperature was slowly raised to 110 °C, and 1.5 mL of diisobutyl phthalate was added during the heating process. After maintaining at 110 °C for 30 min, the liquid was filtered off. Then, it was washed twice with titanium tetrachloride and finally washed three times with hexane and dried to obtain the catalyst C1 for olefin polymerization.

[0215] (2)Propylene polymerization reaction

[0216] In a 5 L stainless steel autoclave, under a nitrogen protection atmosphere, a hexane solution of 1 mmol of triethylaluminum (the concentration of triethylaluminum was 0.5 mmol / mL), 0.05 mmol of methylcyclohexyldimethoxysilane, 10 mL of anhydrous hexane, 5 mg of antioxidant 1010, 10 mg of the catalyst C1 for olefin polymerization obtained in step (1), 1.5 L (standard volume) of hydrogen, 2.5 L of liquid propylene monomer, and 150 mL of ethylene monomer were added. The temperature was raised to 70 °C, and the reaction was carried out at this temperature for 1 h. Then, the temperature was lowered, the pressure was released, the product was discharged, and it was dried to obtain polypropylene powder.

[0217] The activity of the catalyst prepared in this test example was 30.9 kgPP / g•Cat; in the obtained polypropylene powder, the content of the structural unit provided by ethylene was 1.9 wt%. Based on the total weight of the polypropylene powder, polypropylene was 99.5 parts and the antioxidant was 0.5 part.

[0218] The bulk density of the obtained polypropylene powder was 0.41 g / cm 3 , the melt flow rate index was 10.1 g / 10 min. The particle morphology of this polypropylene powder was good, there were basically no abnormal-shaped materials, the molecular weight distribution M w / M n = 4.6, the average particle diameter D(50) = 71.2 μm, the particle size distribution ((D90 - D10) / D50) was 1.65. The melting point T m was 134.9 °C, and the crystallization temperature T c was 107.3 °C. See Table 1 for details.

[0219] Preparation Example 2 of polypropylene powder

[0220] Polypropylene was prepared in a manner similar to Preparation Example 1 of polypropylene powder, except that: in step (2), the volume of hydrogen used was different, and the rest were the same as in Preparation Example 1 of the test example polypropylene powder.

[0221] Specifically: 1.5 L (standard volume) of hydrogen gas was replaced with 6.5 L (standard volume) of hydrogen gas to obtain polypropylene powder.

[0222] The activity of the catalyst prepared in this test example was 30.8 kg PP / g•Cat; in the polypropylene powder obtained, the content of the structural units provided by ethylene was 1.9 wt%. Based on the total weight of the polypropylene powder, 99.5 parts were polypropylene and 0.5 part was antioxidant.

[0223] The bulk density of the obtained polypropylene powder was 0.41 g / cm 3 , and the melt flow rate index was 40.4 g / 10 min. The polypropylene powder had good particle morphology, with basically no abnormal-shaped materials. The molecular weight distribution M w / M n = 4.9, the average particle diameter D(50) = 85 μm, and the particle size distribution ((D90 - D10) / D50) was 1.77. The melting point T m was 129.18 °C, and the crystallization temperature T c was 101.03 °C. See Table 1 for details.

[0224] Preparation Example 3 of Polypropylene Powder

[0225] Polypropylene was prepared in a manner similar to that of Preparation Example 1 of polypropylene powder, except that: in step (1), a different type of catalyst support was used, and antioxidant 168 was used in step (2), and the rest were the same as in Preparation Example 1 of polypropylene powder.

[0226] Specifically: the catalyst spherical support Z2 prepared by Preparation Example 2 of catalyst microspheres with the same weight was used to replace the catalyst spherical support Z1 to obtain the olefin polymerization catalyst C2; then polypropylene powder was prepared using the olefin polymerization catalyst C2 according to step (2) of Preparation Example 1 of polypropylene powder.

[0227] The activity of the catalyst prepared in this test example was 31.5 kg PP / g•Cat; in the polypropylene powder obtained, the content of the structural units provided by ethylene was 1.9 wt%. Based on the total weight of the polypropylene powder, 99.5 parts were polypropylene and 0.5 part was antioxidant.

[0228] The bulk density of the obtained polypropylene powder was 0.41 g / cm 3 , and the melt flow rate index was 9.8 g / 10 min. The polypropylene powder had good particle morphology, with basically no abnormal-shaped materials. The molecular weight distribution M w / M n = 4.7, the average particle diameter D(50) = 74.5 μm, and the particle size distribution ((D90 - D10) / D50) was 1.74. The melting point T mis 137.46 °C, the crystallization temperature T c is 110.03 °C, as shown in Table 1 for details.

[0229] Polypropylene powder preparation example 4

[0230] Polypropylene was prepared in a similar manner to Polypropylene powder preparation example 3, except that: in step (2), the volume of hydrogen used was different, and the rest were the same as in Polypropylene powder preparation example 3.

[0231] Specifically: 1.5 L (standard volume) of hydrogen was replaced with 6.5 L (standard volume) of hydrogen to obtain polypropylene powder.

[0232] The catalyst activity obtained in this test example was 31.1 kgPP / g•Cat; in the polypropylene powder obtained, the content of the structural unit provided by ethylene was 1.9 wt%. Based on the total weight of the polypropylene powder, polypropylene was 99.5 parts and the antioxidant was 0.5 part.

[0233] The bulk density of the obtained polypropylene powder was 0.41 g / cm 3 , the melt flow rate index was 36.7 g / 10 min, the particle morphology of this polypropylene powder was good, there was basically no abnormal-shaped material, and the molecular weight distribution M w / M n = 5.3, the average particle diameter D(50) = 67.1 μm, and the particle size distribution ((D90 - D10) / D50) was 1.91. The melting point T m was 135.18 °C, the crystallization temperature T c was 107.43 °C, as shown in Table 1 for details.

[0234] Polypropylene powder preparation example 5

[0235] Polypropylene was prepared in a similar manner to Polypropylene powder preparation example 1, except that: in step (1), the type of catalyst support used was different, and antioxidant 1076 was used in step (2), and the rest were the same as in Polypropylene powder preparation example 1.

[0236] Specifically: the catalyst spherical support Z3 prepared by Catalyst microsphere preparation example 3 with the same weight was used to replace the catalyst spherical support Z1 to obtain an olefin polymerization catalyst C3; then polypropylene powder was prepared by using the olefin polymerization catalyst C3 according to step (2) of Polypropylene powder preparation example 1.

[0237] The catalyst activity obtained in this test example was 32.4 kgPP / g•Cat; in the polypropylene powder obtained, the content of the structural unit provided by ethylene was 1.9 wt%. Based on the total weight of the polypropylene powder, polypropylene was 99.5 parts and the antioxidant was 0.5 part.

[0238] The bulk density of the obtained polypropylene powder is 0.41 g / cm 3 , the melt flow rate index is 8.8 g / 10 min. The polypropylene powder has good particle morphology, and there are basically no abnormal-shaped materials. The average particle diameter D(50) = 65.6 μm, and the molecular weight distribution M w / M n = 5.3, and the particle size distribution ((D90 - D10) / D50) is 1.84. The melting point T m is 139.55 °C, and the crystallization temperature T c is 113.5 °C. See Table 1 for details.

[0239] Preparation Example 6 of Polypropylene Powder

[0240] Polypropylene was prepared in a manner similar to Preparation Example 5 of polypropylene powder, except that: in step (2), the volume of hydrogen used was different, and the rest were the same as in Preparation Example 5 of the test example polypropylene powder.

[0241] Specifically: 1.5 L (standard volume) of hydrogen was replaced with 6.5 L (standard volume) of hydrogen to obtain polypropylene powder.

[0242] The catalyst activity obtained in this test example is 32.1 kgPP / g•Cat; in the obtained polypropylene powder, the content of the structural unit provided by ethylene is 1.9 wt%. Based on the total weight of the polypropylene powder, polypropylene is 99.5 parts and the antioxidant is 0.5 part.

[0243] The bulk density of the obtained polypropylene powder is 0.41 g / cm 3 , the melt flow rate index is 35.8 g / 10 min. The polypropylene powder has good particle morphology, and there are basically no abnormal-shaped materials. The molecular weight distribution M w / M n = 5.7, the average particle diameter D(50) = 67.3 μm, and the particle size distribution ((D90 - D10) / D50) is 1.87. The melting point T m is 140.2 °C, and the crystallization temperature T c is 117.41 °C. See Table 1 for details.

[0244] Preparation Example 7 of Polypropylene Powder

[0245] Polypropylene powder was prepared in a manner similar to Preparation Example 1 of polypropylene powder, except that: in step (2), the addition amount of the antioxidant used was different, and the rest were the same as in Preparation Example 1 of polypropylene powder. Specifically, 5.5 mg of antioxidant 1010 was added;

[0246] The activity of the catalyst prepared in this test example is 30.3 kg PP / g•Cat; in the prepared polypropylene powder, the content of the structural unit provided by ethylene is 1.9 wt%. Based on the total weight of the polypropylene powder, 99.45 parts of polypropylene and 0.55 parts of antioxidant are used.

[0247] The bulk density of the obtained polypropylene powder is 0.41 g / cm 3 , the melt flow rate index is 9.8 g / 10 min. The polypropylene powder has good particle morphology, and there are basically no abnormal-shaped materials. The molecular weight distribution M w / M n = 4.6, the average particle diameter D(50) = 71.3 μm, and the particle size distribution ((D90 - D10) / D50) is 1.70. The melting point T m is 134.8 °C, and the crystallization temperature T c is 107.0 °C. See Table 1 for details.

[0248] Polypropylene powder preparation example 8

[0249] The polypropylene powder was prepared in a similar manner to polypropylene powder preparation example 1, except that: in step (2), the addition amount of the antioxidant used was different, and the rest were the same as in test example polypropylene powder preparation example 1. Specifically, 6.5 mg of antioxidant 1010 was added;

[0250] The activity of the catalyst prepared in this test example is 29.8 kg PP / g•Cat; in the prepared polypropylene powder, the content of the structural unit provided by ethylene is 1.9 wt%. Based on the total weight of the polypropylene powder, 99.35 parts of polypropylene and 0.65 parts of antioxidant are used.

[0251] The bulk density of the obtained polypropylene powder is 0.41 g / cm 3 , the melt flow rate index is 9.6 g / 10 min. The polypropylene powder has good particle morphology, and there are basically no abnormal-shaped materials. The molecular weight distribution M w / M n = 4.6, the average particle diameter D(50) = 71.5 μm, and the particle size distribution ((D90 - D10) / D50) is 1.72. The melting point T m is 134.6 °C, and the crystallization temperature T c is 106.9 °C. See Table 1 for details.

[0252] Polypropylene powder preparation example 9

[0253] The polypropylene powder was prepared in a similar manner to that in Preparation Example 1 of polypropylene powder, except that: in step (2), the addition amount of the antioxidant used was different, and the rest were the same as those in Preparation Example 1 of polypropylene powder for the test example. Specifically, 7 mg of antioxidant 1010 was added;

[0254] The catalyst activity obtained in this test example was 29.2 kgPP / g•Cat; in the prepared polypropylene powder, the content of the structural unit provided by ethylene was 1.9 wt%. Based on the total weight of the polypropylene powder, 99.3 parts of polypropylene and 0.7 part of antioxidant were used.

[0255] The bulk density of the obtained polypropylene powder was 0.41 g / cm 3 , and the melt flow rate index was 9.5 g / 10 min. The polypropylene powder had good particle morphology, and there were basically no abnormal-shaped materials. The molecular weight distribution M w / M n = 4.6, the average particle diameter D(50) = 71.6 μm, and the particle size distribution ((D90 - D10) / D50) was 1.74. The melting point T m was 134.3 °C, and the crystallization temperature T c was 106.8 °C. See Table 1 for details.

[0256] Preparation Example 10 of polypropylene powder

[0257] The polypropylene powder was prepared in a similar manner to that in Preparation Example 1 of polypropylene powder, except that antioxidant 264 was used instead of antioxidant 1010.

[0258] The catalyst activity obtained in this test example was 27.8 kgPP / g•Cat; in the prepared polypropylene powder, the content of the structural unit provided by ethylene was 1.9 wt%. Based on the total weight of the polypropylene powder, 99.5 parts of polypropylene and 0.5 part of antioxidant were used.

[0259] The bulk density of the obtained polypropylene powder was 0.42 g / cm 3 , and the melt flow rate index was 9.9 g / 10 min. The polypropylene powder had good particle morphology, and there were basically no abnormal-shaped materials. The molecular weight distribution M w / M n = 4.6, the average particle diameter D(50) = 71.2 μm, and the particle size distribution ((D90 - D10) / D50) was 1.76. The melting point T m was 134.7 °C, and the crystallization temperature T c was 107.2 °C. See Table 1 for details.

[0260] Preparation Example 11 of polypropylene powder

[0261] The polypropylene powder was prepared in a similar manner to that in Preparation Example 1 of polypropylene powder, except that the polymerization temperature was 65 °C.

[0262] The catalyst activity obtained in this test example was 31.4 kgPP / g•Cat; in the prepared polypropylene powder, the content of the structural units provided by ethylene was 1.9 wt%. Based on the total weight of the polypropylene powder, 99.5 parts of polypropylene and 0.5 part of antioxidant were used.

[0263] The bulk density of the obtained polypropylene powder was 0.42 g / cm 3 , and the melt flow rate index was 9.3 g / 10 min. The particle morphology of this polypropylene powder was good, with basically no abnormal-shaped materials. The molecular weight distribution M w / M n = 7.1, the average particle diameter D(50) = 76.3 μm, and the particle size distribution ((D90 - D10) / D50) was 1.97. The melting point T m was 136.8 °C, and the crystallization temperature T c was 107.9 °C. See Table 1 for details.

[0264] Comparative Preparation Example 1 of Polypropylene Powder

[0265] The polypropylene powder was prepared in a similar manner to that in Preparation Example 1 of polypropylene powder, except that in step (1), a different type of catalyst support was used, and the rest were the same as those in Preparation Example 1 of polypropylene powder in the test example.

[0266] Specifically: The catalyst spherical support DZ1 prepared from the catalyst microsphere support of Comparative Example 1 with the same weight was used to replace the catalyst spherical support Z1 to obtain the olefin polymerization catalyst DC1. Then, the polypropylene powder was prepared by using the olefin polymerization catalyst DC1 according to step (2) of Preparation Example 1 of polypropylene powder.

[0267] The catalyst activity obtained in this test example was 30.3 kgPP / g•Cat; in the prepared polypropylene powder, the content of the structural units provided by ethylene was 1.9 wt%. Based on the total weight of the polypropylene powder, 99.5 parts of polypropylene and 0.5 part of antioxidant were used.

[0268] The bulk density of the obtained polypropylene powder was 0.37 g / cm 3 , and the melt flow rate index was 8.2 g / 10 min. The molecular weight distribution M w / M n = 8.1, the average particle diameter D(50) = 115 μm, and the particle size distribution ((D90 - D10) / D50) was 2.6. The melting point T m was 135.4 °C, and the crystallization temperature T cIt is 110.6 °C, as can be seen in Table 1 specifically.

[0269] Polypropylene powder Comparative Preparation Example 2

[0270] Prepare polypropylene powder in a manner similar to that of Polypropylene Powder Preparation Example 1, except that: in step (1), the type of catalyst carrier used is different, and the rest are the same as those in Polypropylene Powder Preparation Example 1.

[0271] Specifically: use the catalyst spherical carrier DZ2 prepared from the catalyst microsphere carrier of Comparative Example 2 with the same weight to replace the catalyst spherical carrier Z1 to obtain the olefin polymerization catalyst DC2, and then prepare polypropylene powder according to step (2) of Polypropylene Powder Preparation Example 1 using the olefin polymerization catalyst DC2.

[0272] The catalyst activity obtained in this test example is 31.9 kgPP / g•Cat; in the prepared polypropylene powder, the content of the structural unit provided by ethylene is 1.9 wt%. Based on the total weight of the polypropylene powder, 99.5 parts are polypropylene and 0.5 part is antioxidant.

[0273] The bulk density of the obtained polypropylene powder is 0.41 g / cm 3 , the melt flow rate index is 7.8 g / 10 min, and the molecular weight distribution M w / M n = 8.3, the average particle diameter D(50) = 131.5 μm, and the particle size distribution ((D90 - D10) / D50) is 2.71. The melting point T m is 136.4 °C, and the crystallization temperature T c is 109.2 °C, as can be seen in Table 1 specifically.

[0274] Polypropylene powder Comparative Preparation Example 3

[0275] Prepare polypropylene powder in a manner similar to that of Comparative Example 2 of polypropylene powder, except that: in step (2), the volume of hydrogen used is different, and the rest are the same as those in Comparative Example 2 of polypropylene powder.

[0276] Specifically: replace 1.5 L (standard volume) of hydrogen with 6.5 L (standard volume) of hydrogen to obtain polypropylene powder.

[0277] The catalyst activity obtained in this test example is 31.5 kgPP / g•Cat; in the prepared polypropylene powder, the content of the structural unit provided by ethylene is 1.9 wt%. Based on the total weight of the polypropylene powder, 99.5 parts are polypropylene and 0.5 part is antioxidant.

[0278] The bulk density of the obtained polypropylene powder is 0.41 g / cm 3, the melt flow rate index is 35.5 g / 10 min, the molecular weight distribution M w / M n = 8.2, the average particle diameter D(50) = 127.6 μm, the particle size distribution ((D90 - D10) / D50) is 2.75. The melting point T m is 132.5 °C, the crystallization temperature T c is 106.3 °C, as shown in Table 1 for details.

[0279] Polypropylene powder for comparison, Preparation Example 4

[0280] 1.5 kg of PP pellets (B4808, purchased from Yanshan Petrochemical, MFR = 11.1 g / 10 min) were cryogenically frozen in liquid nitrogen to a temperature below its embrittlement temperature of -35 °C, and then the frozen polypropylene material was put into the cavity of a low-temperature grinder and pulverized by the high-speed rotation of the impeller; the obtained polypropylene powder was classified and collected by an air current sieve, and polypropylene powder with a particle size in the range of 200 - 800 mesh was selected, and the coarse materials that did not meet the fineness requirements were returned to the silo for continued pulverization; 9 mg of antioxidant 1010 was added to the obtained polypropylene powder, and they were put into a high-speed mixer and mixed evenly to obtain polypropylene powder. Among them, in the PP pellets, the content of the structural unit provided by ethylene was 1.75 wt%. Based on the total weight of the polypropylene powder, polypropylene was 99.5 parts and the antioxidant was 0.5 part.

[0281] The bulk density of the obtained polypropylene powder is 0.41 g / cm 3 , the melt flow rate index is 18.6 g / 10 min, the molecular weight distribution M w / M n = 9.4, the average particle diameter D(50) = 40 μm, the particle size distribution ((D90 - D10) / D50) is 3.20. The melting point T m is 132.7 °C, the crystallization temperature T c is 104.3 °C, as shown in Table 1 for details.

[0282] Polypropylene powder for comparison, Preparation Example 5

[0283] Heat up the oil bath pot, install the experimental device, and then add 1.5 kg of polypropylene pellets (the same as in Comparative Example 4), 5.2 L of xylene, and 7.5 mg of antioxidant 1010 to the flask. Stir well to fully dissolve them. Stop heating, and while cooling naturally, add 11.4 L of anhydrous ethanol dropwise to the flask at a rate of 2 mL / min with stirring for precipitation. After the mixed solution cools to room temperature, filter it by vacuum, dry it, and grind it to obtain polypropylene powder. Among them, in the PP pellets, the content of the structural unit provided by ethylene is 1.75 wt%. Based on the total weight of the polypropylene powder, polypropylene is 99.5 parts and the antioxidant is 0.5 part.

[0284] The bulk density of the obtained polypropylene powder is 0.41 g / cm 3 , the melt flow rate index MFR is 9.9 g / 10 min, and the molecular weight distribution M w / M n = 8.8, the average particle diameter D(50) = 86.4 μm, and the particle size distribution ((D90 - D10) / D50) is 2.89. The melting point T m is 129.8 °C, and the crystallization temperature T c is 107.1 °C. See Table 1 for details.

[0285] Polypropylene powder Comparative Preparation Example 6

[0286] Prepare polypropylene powder in a manner similar to that of Polypropylene Powder Preparation Example 1, except that: it does not contain antioxidant.

[0287] The catalyst activity obtained in this test example is 32.5 kgPP / g•Cat; in the prepared polypropylene powder, the content of the structural unit provided by ethylene is 1.9 wt%. Based on the total weight of the polypropylene powder, polypropylene is 100 parts.

[0288] The bulk density of the obtained polypropylene powder is 0.42 g / cm 3 , the melt flow rate index is 10.2 g / 10 min. The particle morphology of this polypropylene powder is good, and there are basically no abnormal-shaped materials. The molecular weight distribution M w / M n = 4.6, the average particle diameter D(50) = 71.1 μm, and the particle size distribution ((D90 - D10) / D50) is 1.73. The melting point T m is 135.1 °C, and the crystallization temperature T c is 107.6 °C. See Table 1 for details.

[0289] Polypropylene powder Comparative Preparation Example 7

[0290] Prepare polypropylene powder in a method similar to that of Polypropylene Powder Preparation Example 1, except that: the addition amount of the antioxidant is different.

[0291] Specifically: 12 mg of antioxidant 1010 is used.

[0292] The activity of the catalyst prepared in this test example is 30.2 kg PP / g•Cat; in the prepared polypropylene powder, the content of the structural unit provided by ethylene is 1.9 wt%. Based on the total weight of the polypropylene powder, 98.8 parts of polypropylene and 1.2 parts of antioxidant are used.

[0293] The bulk density of the obtained polypropylene powder is 0.41 g / cm 3 , the melt flow rate index is 9.1 g / 10 min. The particle morphology of the polypropylene powder is good, there are basically no abnormal-shaped materials, and the molecular weight distribution M w / M n = 4.7, the average particle diameter D(50) = 71.1 μm, and the particle size distribution ((D90 - D10) / D50) is 1.72. The melting point T m is 134.6 °C, and the crystallization temperature T c is 107.1 °C. See Table 1 for details.

[0294] Table 1

[0295]

[0296] Table 1 (continued)

[0297]

[0298] As can be seen from the data shown in Table 1, during the polymerization of polypropylene, by controlling the particle morphology of the olefin polymerization catalyst support, polypropylene powder with a smaller particle size, a narrow particle size distribution, a smooth surface, moderate melt fluidity, and a uniform shape can be directly prepared. This polypropylene powder can be directly used for selective laser sintering 3D printing.

[0299] Examples and Comparative Examples

[0300] In a selective laser sintering printer, 1 kg of the above polypropylene powder preparation example or comparative example is added, and parameters such as the working temperature, laser power, and scanning speed are adjusted to print a spline, as shown in Table 2 specifically. Then, the mechanical properties of the spline are tested, and the specific results are shown in Table 3.

[0301] Table 2

[0302]

[0303] Table 3

[0304]

[0305] When the polypropylene powder provided by the present invention is used for selective laser sintering 3D printing, due to the small particle size of the polypropylene powder, the surface of the prepared 3D printing spline is smooth, showing excellent surface quality. More importantly, the mechanical properties of the 3D printing spline prepared from the polypropylene powder provided by the present invention are significantly higher than those of the polypropylene particles prepared by the prior art. In addition, the printability is also stronger.

[0306] However, the polypropylene powder provided in Comparative Example 5 was interrupted due to obvious size deviation during the printing process because the particles were not smooth and uniform. The polypropylene powder provided in Comparative Example 8 did not contain an antioxidant, resulting in obvious sticking of the polypropylene powder to the roller and interruption during the printing process.

[0307] 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 technical concept of the present invention, various simple modifications can be made to the technical solutions of the present invention, including any other suitable combination of each technical feature. These simple modifications and combinations should also be regarded as the content disclosed by the present invention and fall within the protection scope of the present invention.

Claims

1. A polypropylene powder for 3D printing, characterized in that, The polypropylene powder contains polypropylene and an antioxidant; Based on the total weight of the polypropylene powder, the polypropylene is 99 - 99.5 parts, and the antioxidant is 0.5 - 1 part; The molecular weight distribution index M of the polypropylene powder w / M n is 4 - 8; the particle size distribution of the polypropylene powder is less than 2.5; A method for preparing polypropylene powder for 3D printing, the method comprising: In the presence of a catalyst and an antioxidant, polymerizing an olefin containing propylene and ethylene and / or α-olefin to obtain the polypropylene powder for 3D printing; The catalyst contains a spherical carrier; Wherein, the spherical carrier has the structure shown in formula (1); Formula (1) Among them, in formula (1), R1 is selected from C 1-10 alkyl groups; R2 and R3 are each independently selected from H, C 1-10 alkyl groups and C 1-10 haloalkyl groups substituted by 1-10 halogen atoms; R4 is selected from a haloalkyl group having a C substituted by at least one halogen atom and a haloaryl group having a C substituted by at least one halogen atom; 1-10 6-20 ​​ R5 is selected from C 1-5 alkyl; X is selected from fluorine, chlorine, bromine and iodine; m is 0.1 - 1.9, n is 0.1 - 1.9, and m + n = 2; 0 < q < 0.2; 0 < a < 0.

1.

2. The polypropylene powder according to claim 1, wherein, The particle size distribution of the polypropylene powder is less than 2.

3. The polypropylene powder according to claim 1 or 2, wherein The molecular weight distribution index M w / M n of the polypropylene powder is 4.5 - 6.

4. The polypropylene powder according to claim 1 or 2, wherein The average particle diameter D50 of the polypropylene powder is 10 - 500 μm.

5. The polypropylene powder according to claim 1 or 2, wherein The average particle diameter D50 of the polypropylene powder is 50 - 200 μm.

6. The polypropylene powder according to claim 1 or 2, wherein The melting point T of the polypropylene powder m is 120 - 170 °C.

7. The polypropylene powder according to claim 1 or 2, wherein The melting point Tm of the polypropylene powder is 129 - 160 °C.

8. The polypropylene powder according to claim 1 or 2, wherein The crystallization temperature T of the polypropylene powder c is 80 - 130 °C.

9. The polypropylene powder according to claim 1 or 2, wherein The crystallization temperature T of the polypropylene powder c is 95 - 120 °C.

10. The polypropylene powder according to claim 1 or 2, wherein At 230 °C and a load of 2.16 kg, the melt flow rate MFR of the polypropylene powder is 1 - 1000 g / 10 min.

11. The polypropylene powder according to claim 1 or 2, wherein, At 230 °C and a load of 2.16 kg, the melt flow rate MFR of the polypropylene powder is 1 - 399 g / 10 min.

12. The polypropylene powder according to claim 1 or 2, wherein At 230 °C and a load of 2.16 kg, the melt flow rate MFR of the polypropylene powder is 10 - 50 g / 10 min.

13. The polypropylene powder according to claim 1 or 2, wherein, The bulk density of the polypropylene powder is 0.3 - 0.5 g / cm 3 .

14. The polypropylene powder according to claim 1 or 2, wherein The bulk density of the polypropylene powder is 0.35 - 0.45 g / cm 3 .

15. The polypropylene powder according to claim 1 or 2, wherein Based on the total weight of the polypropylene, the content of structural units provided by the ethylene and / or α-olefin is 1 - 5 wt%.

16. The polypropylene powder according to claim 1 or 2, wherein, The antioxidant is selected from at least one of antioxidant 1010, antioxidant 168 and antioxidant 1076.

17. A method for preparing polypropylene powder for 3D printing according to any one of claims 1-15, characterized in that, The method comprises: In the presence of a catalyst and an antioxidant, polymerizing an olefin containing propylene and ethylene and / or α-olefin to obtain the polypropylene powder for 3D printing; The catalyst contains a spherical carrier; The average particle diameter of the spherical carrier is 2 - 100 microns, and the particle size distribution is less than 2.

18. The method according to claim 17, wherein, The average particle diameter of the spherical carrier is 2 - 19 microns, and the particle size distribution is 0.6 - 1.

6.

19. The method according to claim 17 or 18, wherein The volume ratio of the propylene to the ethylene and / or α-olefin is 12.6 - 80:

1.

20. The method according to claim 17 or 18, wherein Relative to the total amount of the olefin used, the dosage of the antioxidant is 0.5 - 1 wt%.

21. The method according to claim 17 or 18, wherein The antioxidant is selected from at least one of antioxidant 1010, antioxidant 168 and antioxidant 1076.

22. The preparation method according to claim 17, wherein, The spherical carrier is prepared according to the following steps: (1) Component A is subjected to first contact and emulsification in sequence to obtain a first product. Component A contains magnesium halide of the general formula MgXY and a first alcohol compound of the general formula R1OH; (2) The first product is subjected to second contact with component B to obtain a second product. Component B contains an ethylene oxide compound having the structure shown in formula (2); (3) The second product is subjected to third contact with component C to obtain a third product. Component C contains a halogenated alcohol of the general formula R4OH and a second alcohol compound of the general formula R5OH; (4) The third product is spray-dried; Formula (2), Among them, in the formula R1OH, R1 is selected from C 1-10 alkyl groups; In formula (2), R2 and R3 are each independently selected from H, C 1-10 alkyl groups and C 1-10 haloalkyl groups substituted by 1 to 10 halogen atoms; In the formula R4OH, R4 is selected from a haloalkyl group of C substituted by at least one halogen atom and a haloaryl group of C substituted by at least one halogen atom; 1-10 and a haloalkyl group of C substituted by at least one halogen atom and a haloaryl group of C substituted by at least one halogen atom; 6-20 substituted by at least one halogen atom; In the formula R5OH, R5 is selected from an alkyl group of C 1-5 ; In the formula MgXY, X is selected from fluorine, chlorine, bromine and iodine; Y is selected from fluorine, chlorine, bromine, iodine, C 1-6 alkyl groups of 1-6 alkoxy groups of 6-14 aryl groups of 6-14 aryloxy groups; The dosages of the component A, the component B, and the component C are such that the resulting spherical support has the structure shown in formula (1): Formula (1), In formula (1), m is 0.1 - 1.9, n is 0.1 - 1.9, and m + n = 2; 0 < q < 0.2; 0 < a < 0.1; Wherein, in step (3), relative to 1 mol of the magnesium halide, the dosage of the haloalcohol is 0.05 - 6.5 mol, and the dosage of the second alcohol compound is 5 - 100 mol.

23. The preparation method according to claim 22, wherein The magnesium halide is selected from at least one of magnesium chloride, magnesium bromide, phenoxymagnesium chloride, isopropoxymagnesium chloride, and n-butoxymagnesium chloride.

24. The preparation method according to claim 22, wherein, The first alcohol compound is selected from at least one of ethanol, n-propanol, isopropanol, n-butanol, isobutanol, n-pentanol, isopentanol, n-hexanol, n-octanol, and 2-ethylhexanol.

25. The preparation method according to claim 22, wherein, The epoxyethane compound is selected from at least one of ethylene oxide, propylene oxide, butylene oxide, epichlorohydrin, epichlorobutane, epibromopropane, and epibromobutane.

26. The preparation method according to claim 22, wherein The haloalcohol is selected from at least one of 2,2,2-trichloroethanol, 2,2-dichloroethanol, 1,2-dichloroethanol, 1,3-dichloropropanol, and 1,4-dichlorobutanol.

27. The preparation method according to claim 22, wherein Relative to 1 mol of the magnesium halide, the dosage of the first alcohol compound is 6 - 22 mol, the dosage of the epoxyethane compound is 2 - 6 mol, the dosage of the haloalcohol is 1 - 5 mol, and the dosage of the second alcohol compound is 8 - 80 mol.

28. The preparation method according to claim 22 or 23, wherein The first contact is carried out under stirring conditions, and the conditions of the first contact include: the temperature is 80 - 120 °C, and the time is 0.5 - 5 h.

29. The preparation method according to claim 22 or 23, wherein, The first contact is carried out under stirring conditions, and the conditions of the first contact include: the temperature is 80 - 100 °C, and the time is 0.5 - 3 h.

30. The preparation method according to claim 22 or 23, wherein The conditions of the second contact include: the temperature is 50 - 120 °C, and the time is 20 - 60 min.

31. The preparation method according to claim 22 or 23, wherein The conditions of the second contact include: the temperature is 80 - 100 °C, and the time is 20 - 50 min.

32. The preparation method according to claim 22 or 23, wherein The conditions of the spray drying include: the temperature is 60 - 200 °C.

33. The preparation method according to claim 22 or 23, wherein, The conditions of the spray drying include: the temperature is 90 - 150 °C.

34. The preparation method according to claim 17, wherein, The catalyst further includes: a titanium halide compound and an electron donor compound.

35. The preparation method according to claim 34, wherein The titanium halide compound is selected from at least one of titanium tetrachloride, titanium tetrabromide, titanium tetraiodide, tetra-n-butoxytitanium, tetraethoxytitanium, monochloro-tri-n-butoxytitanium, dichloro-di-n-butoxytitanium, trichloro-mon-n-butoxytitanium, monochloro-triethoxytitanium, dichloro-diethoxytitanium, trichloro-mon-ethoxytitanium, and titanium trichloride.

36. The preparation method according to claim 34 or 35, wherein The electron donor compound is selected from at least one of diisobutyl phthalate, carboxylic acid glycol ester, and phosphate ester.

37. Use of the polypropylene powder for 3D printing according to any one of claims 1 - 16 in selective laser sintering 3D printing.

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