Prepolymerization Ziegler-Natta catalyst

Abstract

This disclosure relates to a method for producing a prepolymerized Ziegler-Natta catalyst. The method comprises the steps of: Ai) reacting at least one acyclic alpha-olefin having 2 to 10 carbon atoms in the presence of a Ziegler-Natta catalyst; and Aii) subsequently reacting a vinylcycloalkane, vinylcycloalkene, and / or vinylarene in the presence of a Ziegler-Natta catalyst; or Bi) reacting a vinylcycloalkane, vinylcycloalkene, and / or vinylarene in the presence of a Ziegler-Natta catalyst; and Biii) subsequently reacting at least one acyclic alpha-olefin having 2 to 10 carbon atoms in the presence of a Ziegler-Natta catalyst, wherein the mass ratio of the at least one acyclic alpha-olefin to the Ziegler-Natta catalyst is less than 200:1.

Description

[Technical Field]

[0001] This disclosure relates to a method for producing a prepolymerization Ziegler-Natta catalyst composition. This disclosure also relates to a prepolymerization Ziegler-Natta catalyst composition, a catalyst system for the polymerization of propylene, and a method for producing polypropylene. [Background technology]

[0002] A Ziegler-Natta catalyst generally contains (a) at least one catalytic component formed from transition metal compounds of groups 4-6 of the periodic table (IUPAC, inorganic chemical nomenclature, 1989) and metal compounds of groups 1-3 of the periodic table (IUPAC). A Ziegler-Natta catalyst may also contain compounds of group 13 of the periodic table (IUPAC) and / or internal donor compounds. A Ziegler-Natta catalyst may be used with (b) further catalytic components, such as co-catalysts and / or external donors.

[0003] Various methods for preparing Ziegler-Natta catalysts are known. For example, methods for preparing such catalysts are described in EP 1403292 A1, EP 0949280 A1, US-A-4294948, US-A-5413979, US-A-5409875, and EP 1273595 A1.

[0004] A prepolymerization Ziegler-Natta catalyst composition can be formed by polymerizing vinyl monomers in the presence of a Ziegler-Natta catalyst. This prepolymerization Ziegler-Natta catalyst composition is then used to catalyze the polymerization of olefins. By using this prepolymerization Ziegler-Natta catalyst composition, improved properties can be imparted to the final polymer.

[0005] WO 2018 / 011165 and EP 2960256 describe solid catalyst particles comprising a Ziegler-Natta catalyst and a polymer nucleating agent, the polymer nucleating agent containing vinyl monomer units such as vinylcyclohexane and obtainable in the presence of a Ziegler-Natta catalyst. WO 2020 / 064568 describes prepolymerizing a solid ZN catalyst component in the presence of one or more olefin monomers selected from C2, C3, or C4 olefin monomers and mixtures thereof to obtain a prepolymerized solid ZN catalyst.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Patent Document 2

Patent Document 3

Patent Document 4

Patent Document 5

Patent Document 6

Patent Document 7

Patent Document 8

Patent Document 9

Patent Document 10

Patent Document 11

Patent Document 12

Patent Document 13

Patent Document 14

Patent Document 15

[0007] According to a first aspect, the present disclosure provides a method for producing a prepolymerized Ziegler-Natta catalyst composition. [Means for solving the problem]

[0008] The method is, A step of reacting at least one acyclic alpha-olefin having 2 to 10 carbon atoms in the presence of a Ziegler-Natta catalyst, and Aii) A step of subsequently reacting vinylcycloalkanes, vinylcycloalkenes, and / or vinylarenes in the presence of a Ziegler-Natta catalyst; or A step of reacting a vinylcycloalkane, vinylcycloalkene, and / or vinylarene in the presence of a Ziegler-Natta catalyst, and Bii) The process of reacting at least one acyclic alpha-olefin having 2 to 10 carbon atoms in the presence of a Ziegler-Natta catalyst. Includes, Bi) Vinylcycloalkanes, vinylcycloalkenes, and / or vinylarenes are reacted in the presence of a Ziegler-Natta catalyst, and Bi) thereafter, at least one acyclic alpha-olefin having 2 to 10 carbon atoms is reacted in the presence of a Ziegler-Natta catalyst, such that the mass ratio of at least one acyclic alpha-olefin to the Ziegler-Natta catalyst is less than 200:1.

[0009] According to a second aspect, the disclosure also provides a prepolymerization Ziegler-Natta catalyst composition that can be obtained or obtained by the method of the first aspect described herein.

[0010] According to a third aspect, the present disclosure provides a catalyst system for the polymerization of propylene, comprising a prepolymerization Ziegler-Natta catalyst composition, a co-catalyst, and an external donor according to the second aspect described herein.

[0011] According to a fourth aspect, the present disclosure provides a method for producing polypropylene, comprising the step of polymerizing propylene in the presence of a prepolymerization Ziegler-Natta catalyst composition according to the second aspect described herein. [Modes for carrying out the invention]

[0012] As described above, a first aspect of the present disclosure provides a method for producing a prepolymerized Ziegler-Natta catalyst composition.

[0013] The method is, A step of reacting at least one acyclic alpha-olefin having 2 to 10 carbon atoms in the presence of a Ziegler-Natta catalyst, and Aii) A step of subsequently reacting vinylcycloalkanes, vinylcycloalkenes, and / or vinylarenes in the presence of a Ziegler-Natta catalyst; or Bi) A step of reacting vinylcycloalkanes, vinylcycloalkenes, and / or vinylarenes in the presence of a Ziegler-Natta catalyst, and Bii) The process of reacting at least one acyclic alpha-olefin having 2 to 10 carbon atoms in the presence of a Ziegler-Natta catalyst. Includes, Bi) vinylcycloalkanes, vinylcycloalkenes, and / or vinylarenes are reacted in the presence of a Ziegler-Natta catalyst, and Bi) then at least one acyclic alpha-olefin having 2 to 10 carbon atoms is reacted in the presence of a Ziegler-Natta catalyst, the mass ratio of the at least one acyclic alpha-olefin to the Ziegler-Natta catalyst is less than 200:1, preferably less than 100:1, for example 10:90 to 90:10.

[0014] This disclosure also relates to a method for producing a prepolymerized Ziegler-Natta catalyst composition. The method is as follows: a) A step of polymerizing at least one acyclic alpha-olefin having 2 to 10 carbon atoms in the presence of a Ziegler-Natta catalyst, and b) A step of polymerizing vinylcycloalkanes, vinylcycloalkenes, and / or vinylarenes in the presence of the same Ziegler-Natta catalyst. Includes, Steps a) and b) are carried out separately or sequentially in any order to prepare a prepolymerized Ziegler-Natta catalyst composition comprising a Ziegler-Natta catalyst, a polymer having polymerization units derived from at least one acyclic alpha-olefin having 2 to 10 carbon atoms, and a polymer having polymerization units derived from vinylcycloalkane, vinylcycloalkene, and / or vinylarene, provided that if step a) is carried out before step a), the mass ratio of at least one acyclic alpha-olefin to the Ziegler-Natta catalyst is less than 200:1.

[0015] The prepolymerization Ziegler-Natta catalyst composition can be used as a catalyst for the polymerization of polymers, such as propylene.

[0016] Advantageously, the prepolymerization process leads to the formation of polymers that act as nucleating agents. While not intended to be bound by any particular theory, the polymers include polymerization units derived from at least one acyclic alpha-olefin having 2 to 10 carbon atoms (e.g., 1-butene) and polymerization units derived from vinylcycloalkanes or vinylarenes (e.g., vinylcyclohexane). Subsequently, when polypropylene is produced in the presence of the prepolymerization catalyst composition, these polymers influence the crystallinity of the resulting polypropylene. By improving crystallinity, the resulting polypropylene may have improved mechanical, thermal, and / or optical properties.

[0017] Higher crystallinity of polypropylene is achieved at a higher crystallization temperature T cThis can be demonstrated by the following: A higher degree of crystallinity can result in polypropylene with a higher modulus of elasticity, such as tensile modulus. In some examples, a Ziegler-Natta prepolymerization catalyst can be used to produce polypropylene with improved stiffness.

[0018] Using a prepolymerization Ziegler-Natta catalyst, polypropylene with improved thermal properties can be produced. Such improved thermal properties include, for example, improved mechanical properties when exposed to higher temperatures. For instance, using a prepolymerization Ziegler-Natta catalyst can produce polypropylene with reduced elongation at higher temperatures, improved dimensional stability, and / or reduced creep.

[0019] In some cases, prepolymerization is performed using a Ziegler-Natta catalyst to reduce the enthalpy of fusion H m This can produce higher quality polypropylene.

[0020] In some cases, prepolymerization using a Ziegler-Natta catalyst can be used to produce polypropylene with improved optical properties, such as clarity, transparency, and / or haze. In some cases, such properties may be improved when exposed to high temperatures, such as those that occur during exposure to elevated temperatures in sterilization or pasteurization processes.

[0021] In this disclosure, at least one acyclic alpha-olefin having 2 to 10 carbon atoms is reacted in the presence of a Ziegler-Natta catalyst (e.g., Ai) or Bii)). Preferred acyclic alpha-olefins are described in further detail below. However, the acyclic alpha-olefin is preferably selected from at least one of ethylene, propylene, 1-butene, 1-pentene, 1-hexene, 1-heptene, and 1-octene. For example, the acyclic alpha-olefin may be 1-butene. The reaction can produce a polymer having polymerization units derived from at least one acyclic alpha-olefin having 2 to 10 carbon atoms (e.g., 1-butene).

[0022] The mass ratio of at least one acyclic alpha-olefin having 2 to 10 carbon atoms to the Ziegler-Natta catalyst may be 200:1 or less, for example, 100:1 or less. If the method includes steps Bi) and Bii), the mass ratio of at least one acyclic alpha-olefin having 2 to 10 carbon atoms to the Ziegler-Natta catalyst is 200:1 or less, for example, 100:1 or less. If the method includes steps Ai) and Aii), the mass ratio of at least one acyclic alpha-olefin having 2 to 10 carbon atoms to the Ziegler-Natta catalyst is preferably 200:1 or less, for example, 100:1 or less. The mass ratio of at least one acyclic alpha-olefin having 2 to 10 carbon atoms to the Ziegler-Natta catalyst may be 10:90 to 90:10. For example, the mass ratio of at least one acyclic alpha-olefin to the Ziegler-Natta catalyst is 20:80 to 80:20, preferably 30:70 to 70:30, more preferably 40:60 to 60:40, and even more preferably 55:45 to 45:55.

[0023] Preferably, in step Ai) or step Bii), the mass ratio of at least one acyclic alpha-olefin having 2 to 10 carbon atoms to the Ziegler-Natta catalyst is 10:90 to 90:10. For example, in step Ai) or step Bii), the mass ratio of at least one acyclic alpha-olefin to the Ziegler-Natta catalyst may be 20:80 to 80:20, preferably 30:70 to 70:30, more preferably 40:60 to 60:40, and even more preferably 55:45 to 45:55.

[0024] In this disclosure, vinylcycloalkanes, vinylcycloalkenes, and / or vinylarenes are reacted in the presence of a Ziegler-Natta catalyst (e.g., in step Aii) or Bi). Suitable vinylcycloalkanes, vinylcycloalkenes, and vinylarenes are described below. However, vinylcycloalkanes are preferred. The vinylcycloalkane may be selected from vinylcyclohexane, vinylcyclopentane, vinyl-2-methylcyclohexane, and vinylnorbornane. More preferably, the vinylcycloalkane is vinylcyclohexane.

[0025] Sequential reactions in steps Ai) and Aii), or sequential reactions in Bi) and Biii), can yield a prepolymerization Ziegler-Natta catalyst composition containing polymers having polymerization units derived from at least one acyclic alpha-olefin having 2 to 10 carbon atoms, and polymers having polymerization units derived from vinylcycloalkanes, vinylcycloalkenes, and / or vinylarenes. The polymers in the prepolymerization Ziegler-Natta catalyst composition can act as nucleating agents to impart improved crystallinity to the final polypropylene. The sequential nature of reactions Ai) and Aii), and Bi) and Biii), allows for the sequential generation of different polymers that act as nucleating agents (e.g., (1) polymers having polymerization units derived from at least one acyclic alpha-olefin having 2 to 10 carbon atoms, and (2) polymers having polymerization units derived from vinylcycloalkanes, vinylcycloalkenes, and / or vinylarenes).

[0026] Preferably, in step Aii) or step Bi), the mass ratio of vinylcycloalkane or vinylarene to the Ziegler-Natta catalyst is less than 200:1, more preferably less than 100:1, for example 10:90 to 90:10. In some examples, the mass ratio of vinylcycloalkane to the Ziegler-Natta catalyst is 20:80 to 80:20, preferably 30:70 to 70:30, more preferably 40:60 to 60:40, and even more preferably 55:45 to 45:55.

[0027] Preferably, the Ziegler-Natta catalyst comprises a transition metal compound selected from groups 4 to 6 of the periodic table, a group 1 to 3 metal compound, and an internal donor. More preferably, the Ziegler-Natta catalyst comprises a titanium compound, a magnesium compound, and an internal donor. As detailed below, the internal donor may be a non-phthalate ester.

[0028] In some examples, at least one of steps Ai) and Aii), or at least one of steps Bi) and Biii), is carried out in the presence of a cocatalyst and optionally in the presence of an external donor.

[0029] As described above, this disclosure also provides a method for producing polypropylene. The method includes the step of polymerizing propylene in the presence of a prepolymerized Ziegler-Natta catalyst composition, which can be obtained by the method for producing the prepolymerized Ziegler-Natta catalyst composition described herein. The prepolymerized Ziegler-Natta catalyst composition can be used as part of a catalyst system further comprising a cocatalyst and an external donor.

[0030] Prepolymerization using Ziegler-Natta catalysts In one embodiment (Ai) and Aii)) of the present disclosure, at least one acyclic alpha-olefin is reacted in the presence of a Ziegler-Natta catalyst. Subsequently, a vinylcycloalkane, vinylcycloalkene, and / or vinylarene are reacted in the presence of a Ziegler-Natta catalyst. Thus, in step Aii), the vinylcycloalkane, vinylcycloalkene, and / or vinylarene are reacted in the presence of the Ziegler-Natta catalyst that was present in the reaction of at least one acyclic alpha-olefin in step Ai). In some examples, the Ziegler-Natta catalyst remains unchanged (identical) between steps Ai) and Aii).

[0031] Since step Aii) follows step Ai), step Aii) is performed after step Ai). However, Aii) does not have to follow immediately after Ai), and an intermediate reaction step may be performed between Ai) and Aii). However, in some embodiments, Aii) is performed immediately after Ai).

[0032] Preferably, in step Ai), at least one acyclic alpha-olefin may be reacted in the presence of a Ziegler-Natta catalyst to produce an intermediate or modified Ziegler-Natta catalyst composition containing a polymer having units derived from at least one acyclic alpha-olefin. In step Aii), vinylcycloalkane, vinylcycloalkene, and / or vinylarene are then reacted in the presence of the intermediate or modified Ziegler-Natta catalyst composition. The resulting product mixture may contain a polymer having units derived from at least one acyclic alpha-olefin and a polymer having units derived from vinylcycloalkane, vinylcycloalkene, and / or vinylarene.

[0033] In other embodiments (Bi) and Bii), vinylcycloalkanes, vinylcycloalkenes, and / or vinylarenes are reacted in the presence of a Ziegler-Natta catalyst. Then, at least one acyclic alpha-olefin is reacted in the presence of the Ziegler-Natta catalyst. Thus, in step Bii), at least one acyclic alpha-olefin is reacted in the presence of the Ziegler-Natta catalyst that was present in the reaction of at least one acyclic alpha-olefin in step Bi). In some examples, the Ziegler-Natta catalyst remains unchanged (identical) in steps Bi) and Bii).

[0034] Since step Bi) follows step Bi), step Bi) is performed after step Bi). However, Bi) does not have to follow immediately after Bi), and an intermediate reaction step may be performed between Bi) and Bi)). However, in some embodiments, Bi) is performed immediately after Bi).

[0035] Preferably, in step Bi), vinylcycloalkanes, vinylcycloalkenes, and / or vinylarenes may be reacted in the presence of a Ziegler-Natta catalyst to produce an intermediate Ziegler-Natta catalyst composition containing a polymer having units derived from vinylcycloalkanes, vinylcycloalkenes, and / or vinylarenes. In step Bii), at least one acyclic alpha-olefin is then reacted in the presence of the intermediate Ziegler-Natta catalyst composition. The resulting product mixture may contain a polymer having units derived from at least one acyclic alpha-olefin and a polymer having units derived from vinylcycloalkanes, vinylcycloalkenes, and / or vinylarenes.

[0036] Sequential reactions make it possible to form a second polymer after forming a first polymer.

[0037] The prepolymerization process results in the formation of polymers that can act as nucleating agents. These polymers may have polymerization units derived from at least one acyclic alpha-olefin (e.g., 1-butene) having 2 to 10 carbon atoms. The polymers may also have polymerization units derived from vinylcycloalkanes (e.g., vinylcyclohexane), vinylcycloalkenes, or vinylarenes. In some examples, the polymers may have both polymerization units derived from at least one acyclic alpha-olefin (e.g., 1-butene) having 2 to 10 carbon atoms and polymerization units derived from vinylcycloalkanes, vinylcycloalkenes, or vinylarenes (e.g., vinylcyclohexane).

[0038] These polymers can be incorporated into the final polypropylene. Polymers formed in the prepolymerization reaction act as nucleating agents, influencing the crystallinity and / or crystallization behavior of the resulting polypropylene. For example, if propylene is subsequently formed in the presence of a Ziegler-Natta prepolymerization catalyst, the present polymer nucleating agents may influence the crystallinity and / or crystallization behavior of the resulting polypropylene. However, these polymers do not necessarily need to be present in detectable amounts in the final polypropylene composition.

[0039] The acyclic alpha-olefin used to form the prepolymerization Ziegler-Natta catalyst composition is of formula C n H 2n The formula may be a branched or unbranched hydrocarbon having one carbon-carbon double bond, where n is 2 to 10. In this disclosure, the carbon-carbon double bond is located at the alpha position. Preferably, n is 2 to 9, for example 2 to 8. In some embodiments, n is 2 or 4 to 8, for example 2, 4, 5, 6, 7, or 8. In a preferred embodiment, n is 4. For example, the acyclic alpha-olefin used in step Ai) may be 1-butene.

[0040] Acyclic alpha-olefins are preferably linear in shape.

[0041] Suitable acyclic alpha-olefins include ethylene, propylene, 1-butene, 1-pentene, 1-hexene, 1-heptene, and 1-octene. Preferably, the acyclic alpha-olefin is ethylene, propylene, 1-butene, 1-pentene, 1-hexene, 1-heptene, and / or 1-hexene. In some embodiments, the acyclic alpha-olefin is not propylene. More preferably, the acyclic alpha-olefin is ethylene, 1-butene, 1-pentene, 1-hexene, 1-heptene, and / or 1-hexene, and even more preferably, the acyclic alpha-olefin is ethylene, 1-butene, 1-pentene, or 1-hexene. More preferably, the acyclic alpha-olefin is 1-butene. However, other examples of acyclic alpha-olefins include 3-methyl-1-butene, 3-ethyl-1-hexene, 3-methyl-1-pentene, and 4-methyl-1-pentene. Combinations of two or more acyclic alpha-olefins may also be used. For example, 1-butene and ethylene can be used in combination to produce copolymers that can act as nucleating agents.

[0042] Preferably, one type of acyclic alpha-olefin is reacted in the presence of a Ziegler-Natta catalyst. However, in some examples, the copolymerization reaction in step Ai) or Bii) is carried out in the presence of a mixture of two or more acyclic alpha-olefins and the Ziegler-Natta catalyst.

[0043] In step Bii), the mass ratio of at least one acyclic alpha-olefin having 2 to 10 carbon atoms to the Ziegler-Natta catalyst is less than 200:1, preferably less than 100:1. The mass ratio may be less than 50:1, preferably less than 20:1, and more preferably less than 10:1. In one embodiment, the ratio is 10:90 to 90:10, preferably 20:80 to 80:20, more preferably 30:70 to 70:30, and even more preferably 40:60 to 60:40, for example 45:55 to 55:45.

[0044] In step Ai), the mass ratio of at least one acyclic alpha-olefin having 2 to 10 carbon atoms to the Ziegler-Natta catalyst may be less than 200:1, preferably less than 100:1, for example 10:90 to 90:10. The mass ratio may be less than 50:1, preferably less than 20:1, more preferably less than 10:1. In one embodiment, the ratio is 10:90 to 90:10, preferably 20:80 to 80:20, more preferably 30:70 to 70:30, and even more preferably 40:60 to 60:40, for example 45:55 to 55:45.

[0045] As described above, when acyclic alpha-olefins are reacted in the presence of a Ziegler-Natta catalyst, polymers are produced that have polymerization units derived from at least one acyclic alpha-olefin having 2 to 10 carbon atoms (e.g., 1-butene). For example, the polymer may be polyethylene, polypropylene, polybutene, polypentene, polyhexene, polyheptene, or polyoctene. Preferably, the polymer is polybutene (e.g., in step Ai). The polymer is preferably a homopolymer. However, in some examples, the polymer chain may be a copolymer chain formed from two or more different acyclic alpha-olefins as comonomers. For example, the copolymer chain may contain units derived from 1-butene and ethylene.

[0046] In steps Aii) and Bi), vinylcycloalkanes, vinylcycloalkenes, or vinylarenes are reacted in the presence of a Ziegler-Natta catalyst.

[0047] Vinylcycloalkanes, vinylcycloalkenes, or vinylarenes are defined by the formula: CH2=CR 1 R 2 (In the formula, R 1 is H or -CH3, preferably H. R 2is an optionally substituted cycloalkyl ring, an optionally substituted cycloalkenyl ring, and / or an optionally substituted aryl ring, or an optionally substituted fused ring system) It may have. The ring or fused ring system may contain 4 to 20 carbon atoms. Preferably, the ring or fused ring system may contain 5 to 12 carbon atoms. The ring or fused ring system may be unsubstituted or may be optionally substituted with one or more C1-C6 alkyl groups, such as a methyl group. R 2 When is an optionally substituted cycloalkenyl, the cycloalkenyl may have one, two, or three C=C double bonds.

[0048] In some examples, R 2 may contain 5 to 7 carbons.

[0049] R 2 When is an optionally substituted aryl, it may be an optionally substituted phenyl ring.

[0050] R 2 When is an optionally substituted cycloalkenyl, it may be an optionally substituted cyclohexenyl ring.

[0051] Preferably, R 2 is an optionally substituted cycloalkyl ring. More preferably, R 2 may be a cyclopentyl, cyclohexyl, or norbornyl ring.

[0052] Preferably, vinyl cycloalkane is used. The vinyl cycloalkane may be selected from vinyl cyclohexane, vinyl cyclopentane, vinyl-2-methyl cyclohexane, and vinyl norbornane. More preferably, the vinyl cycloalkane is vinyl cyclohexane.

[0053] In some examples, vinyl arene may be used. A suitable vinyl arene is styrene. In one example, 1-methyl styrene is used.

[0054] In step Aii) or Bi), the mass ratio of vinylcycloalkane, vinylcycloalkene, and / or vinylarene to the Ziegler-Natta catalyst may be less than 200:1, preferably less than 100:1. The mass ratio may be less than 50:1, preferably less than 20:1, and more preferably less than 10:1.

[0055] In some examples, in step Aii) or Bi), the mass ratio of vinylcycloalkane, vinylcycloalkene, and / or vinylarene to the Ziegler-Natta catalyst may be 10:90 to 90:10. In some examples, in step Aii) or Bi), the mass ratio of vinylcycloalkane, vinylcycloalkene, or vinylarene to the Ziegler-Natta catalyst is 20:80 to 80:20, preferably 30:70 to 70:30, more preferably 40:60 to 60:40, and even more preferably 45:55 to 55:45.

[0056] When vinylcycloalkanes, vinylcycloalkenes, and / or vinylarenes are reacted in the presence of a Ziegler-Natta catalyst, polymers having polymerization units derived from vinylcycloalkanes, vinylcycloalkenes, and / or vinylarenes (e.g., vinylcyclohexane) are produced. The polymers are preferably homopolymers. In one example, the polymer is polyvinylcyclohexane.

[0057] In some examples, the ratio of the mass of the acyclic alpha-olefin reacted in the presence of the Ziegler-Natta catalyst to the mass of the vinylcycloalkane, vinylcycloalkene, or vinylarene reacted in the presence of the Ziegler-Natta catalyst may be 10:90 to 90:10, for example 20:80 to 80:20, preferably 30:70 to 70:30, more preferably 40:60 to 60:40, and even more preferably 45:55 to 55:45.

[0058] The degree of prepolymerization of the prepolymerization Ziegler-Natta catalyst may be 0.1 to 100 g polyolefin / g Ziegler-Natta catalyst, more preferably 0.2 to 80 g polyolefin / g Ziegler-Natta catalyst, even more preferably 0.3 to 50 g polyolefin / g Ziegler-Natta catalyst, even more preferably 0.4 to 40 g polyolefin / g Ziegler-Natta catalyst, and still more preferably 0.5 to 30 g polyolefin / g Ziegler-Natta catalyst. The degree of prepolymerization can be determined from the mass of the reacted monomer and the mass of the Ziegler-Natta catalyst used in the reaction.

[0059] Prepolymerization can be carried out in any inert fluid that does not dissolve the formed polymer. The viscosity of the final catalyst / polymerized vinyl compound / inert liquid mixture should also be high enough to prevent the catalyst particles from settling during storage and transport. The viscosity of the mixture can be adjusted either before or after the polymerization of the vinyl compound. For example, prepolymerization can be carried out in a low-viscosity oil, and the viscosity can be adjusted by adding a high-viscosity substance after the prepolymerization of the vinyl compound. Such a high-viscosity substance can be a "wax," such as oil, or a mixture of oil and a solid or high-viscosity substance (oil-grease). The viscosity of such a viscous substance is typically 1,000 to 15,000 cP at room temperature. The advantage of using wax is that the storage and supply of the catalyst to the process are improved.

[0060] The mass ratio of oil to solid or high-viscosity polymer is preferably less than 5:1. A suitable mass ratio can be determined experimentally.

[0061] In addition to viscous substances, liquid hydrocarbons such as isobutane, propane, pentane, and hexane can also be used as media in the modification process.

[0062] Preferably, the polypropylene produced using the prepolymerization catalyst is essentially free of free (unreacted) vinyl compounds. This means that the vinyl compounds can be completely reacted during prepolymerization. For this purpose, the total mass ratio of the vinyl compounds added over steps Ai) and Aii) or Bi) and Biii) to the catalyst should be in the range of 0.2 to 10, preferably less than 3, more preferably about 0.2 to 2.0, and particularly about 0.3 to 1.5. It should be noted that the use of excessive vinyl compounds yields only limited benefits.

[0063] Furthermore, the reaction time for prepolymerization should be sufficient to allow for the complete reaction of the vinyl monomer, i.e., polymerization should be continued until the amount of unreacted vinyl compound in the reaction mixture (including the polymerization medium and reactants) is less than 0.5% by mass, particularly less than 2000 ppm by mass (as shown by analysis). In some embodiments, a second monomer is added (i.e., steps Aii) or Bii) after the complete reaction of the first monomer reacted in the presence of the catalyst (i.e., step Ai) or Bi). Thus, if the prepolymerization catalyst contains a maximum of about 0.1% by mass of vinyl compound, the final vinyl compound content in polypropylene may be below the detection limit by GC-MS (<0.01 ppm by mass). Generally, when operating on an industrial scale, a polymerization time of at least 30 minutes is required, preferably at least 1 hour, particularly at least 5 hours. Polymerization times in the range of 6 to 50 hours can also be used. Prepolymerization of the Ziegler-Natta catalyst can be carried out at a temperature of 10 to 90°C, preferably 20 to 65°C. The reaction temperature can be varied depending on the properties of the monomers being reacted in the presence of the Ziegler-Natta catalyst. For example, the reaction temperature for polymerization of at least one acyclic alpha-olefin may be lower than the reaction temperature for polymerization of vinylcycloalkanes, vinylcycloalkenes, and / or vinylarenes. Therefore, preferably, step Ai) is carried out at a lower temperature than step Aii).

[0064] Polymerization may be carried out in the presence of a cocatalyst and, optionally, an external donor.

[0065] General conditions for catalyst prepolymerization are also disclosed in WO 00 / 6831, which are incorporated herein by reference.

[0066] In this disclosure, prepolymerization can be advantageously carried out in sequential steps. Preferably, steps Ai) and Aii), or Bi) and Biii), are carried out sequentially in the same reactor or reaction medium.

[0067] In one example of this disclosure, the Ziegler-Natta catalyst may be dispersed in a solvent to form a slurry. In step Ai), at least one acyclic alpha-olefin (e.g., 1-butene) may be added to the slurry. The reaction temperature may be maintained at 10 to 90°C. In some examples, the temperature in step Ai) may be 15 to 40°C, for example, 20 to 30°C, especially when the acyclic alpha-olefin is 1-butene. Before adding at least one acyclic alpha-olefin (e.g., 1-butene), a co-catalyst and an external donor may be added to the slurry. The co-catalyst and external donor can activate the catalyst.

[0068] At least one acyclic alpha-olefin (e.g., 1-butene) and the Ziegler-Natta catalyst may be reacted for a sufficient time to polymerize at least one acyclic alpha-olefin. In some examples, the reaction is carried out so that most of the added acyclic alpha-olefin (e.g., 1-butene) is consumed. During the reaction, the slurry may be stirred or agitated by other means.

[0069] An intermediate product containing the Ziegler-Natta catalyst and the polymerized acyclic alpha-olefin (e.g., 1-butene) may be separated before step Aii), which is the second step of the method. However, it is preferable that step Aii), which is the second step of the prepolymerization reaction, be carried out in the same reactor or reaction medium. For example, vinylcycloalkanes (e.g., vinylcyclohexane), vinylcycloalkenes, or vinylarenes may be introduced into the same reaction medium. The reaction temperature may be varied depending on the circumstances. For example, in one embodiment, the reaction temperature may be raised to 40-90°C, preferably 50-70°C, more preferably 55-65°C. The reaction may be carried out for a sufficient time to polymerize the vinylcycloalkanes (e.g., vinylcyclohexane), vinylcycloalkenes, or vinylarenes and produce a prepolymerized Ziegler-Natta catalyst composition.

[0070] In an alternative embodiment, the Ziegler-Natta catalyst may be dispersed in a solvent to form a slurry. In step Bi), a vinylcycloalkane (e.g., vinylcyclohexane), vinylcycloalkene, or vinylarene may be added to the slurry. The co-catalyst and external donor may be added to the slurry before the addition of the monomer. The co-catalyst and external donor can activate the catalyst.

[0071] Vinylcycloalkanes (e.g., vinylcyclohexane), vinylcycloalkenes, or vinylarenes may be reacted with the Ziegler-Natta catalyst for a sufficient amount of time to polymerize the monomers. In some examples, the reaction is carried out so that most of the added monomers are consumed. During the reaction, the slurry may be stirred or agitated by other means.

[0072] The intermediate product, which includes the Ziegler-Natta catalyst and the polymerized vinylcycloalkane (e.g., vinylcyclohexane), vinylcycloalkene, or vinylarene, may be separated before step Bii), which is the second step of the method. However, it is preferable that step Bii), which is the second step of the prepolymerization reaction, be carried out in the same reactor or reaction medium. For example, at least one acyclic alpha-olefin may be introduced into the same reaction medium. The reaction temperature may be varied depending on the circumstances. The reaction may be carried out for a sufficient amount of time to polymerize at least one acyclic alpha-olefin and produce a prepolymerized Ziegler-Natta catalyst composition.

[0073] The prepolymerization catalyst may be recovered and used in a method for polymerizing propylene.

[0074] Ziegler-Natta catalyst The Ziegler-Natta catalyst is a solid component comprising a transition metal compound selected from groups 4-6 of the periodic table (IUPAC), a metal compound from groups 1-3 of the periodic table (IUPAC), and an internal donor.

[0075] Preferably, the transition metal compound selected from groups 4 to 6 of the periodic table (IUPAC) is a titanium compound. More preferably, the titanium compound is a titanium halide, most preferably TiCl4. The transition metal compound (e.g., titanium compound) may be present in an amount of about 1 to about 6% by mass.

[0076] Preferably, the compounds are magnesium compounds of metals from groups 1 to 3 of the periodic table (IUPAC). The metal compound (e.g., magnesium compound) may be present in an amount of about 10 to about 20% by mass.

[0077] In some examples, the internal donor is a non-phthalate compound. Preferably, the internal donor is a non-phthalate ester, and more preferably a diester of a non-phthalate dicarboxylic acid. The internal donor may be a non-phthalate ester selected from the group consisting of optionally substituted malonates, maleates, succinates, glutarates, citraconates, and their derivatives and / or mixtures. Even more preferably, the internal donor is selected from substituted maleates and citraconates, and most preferably the internal donor is a citraconate. The internal donor (e.g., a non-phthalate compound, e.g., citraconate) may be present in an amount of about 5 to about 10% by mass.

[0078] Ideally, the catalyst is substantially or completely free of undesirable phthalate compounds. For example, if present, phthalate compounds are present in an amount of less than 1% by mass, preferably less than 0.5% by mass, and more preferably less than 0.2% by mass, of the mass of the catalyst. In one preferred embodiment, the catalyst is completely free of phthalate compounds. Furthermore, the solid catalyst does not contain any external supporting material such as silica, but the catalyst is self-supporting. It is surprising that effective nucleation can occur during prepolymerization with "bulky" monomers such as vinylcycloalkanes, vinylcycloalkenes, and / or vinylarenes when the catalyst is substantially or completely free of phthalate compounds, because such internal donors are considered favorable for the effective formation of prepolymers. However, it has been surprisingly found that desirable prepolymers can be formed in the absence of such phthalate compounds. Prepolymerization is so remarkably effective that when polypropylene is subsequently produced in the presence of the prepolymerization catalyst composition, these polymers influence the crystallinity of the resulting polypropylene. By improving the crystallinity, the resulting polypropylene may have improved mechanical, thermal, and / or optical properties.

[0079] In a preferred example, the Ziegler-Natta catalyst comprises a titanium compound, a magnesium compound, and an internal donor, preferably containing about 1 to about 6% by mass of the titanium compound, about 10 to about 20% by mass of the magnesium compound, and about 5 to about 10% by mass of the internal donor.

[0080] Detailed descriptions of the preparation of the Ziegler-Natta catalyst are disclosed in WO2012 / 007430, EP2415790, EP2610270, EP2610271, EP2610272, WO / 2020064568, and EP2960256, which are incorporated herein by reference.

[0081] The Ziegler-Natta catalyst can be further defined by the method by which it can be obtained. Therefore, the Ziegler-Natta catalyst is preferably, a1) A step of preparing a solution of at least a group 2 metal alkoxy compound (Ax), wherein Ax is optionally a reaction product of a group 2 metal compound (MC) in an organic liquid reaction medium and a monohydric alcohol (A) containing at least one ether moiety in addition to the hydroxyl moiety, or a2) A step of preparing a solution of at least a group 2 metal alkoxy compound (Ax'), wherein Ax' is optionally a reaction product of a group 2 metal compound (MC) with an alcohol mixture of a monohydric alcohol (A) and a monohydric alcohol of formula ROH (B) in an organic liquid reaction medium, or a3) A step of preparing a solution of a mixture of a group 2 metal alkoxy compound ((Ax)) and a group 2 metal alkoxy compound (Bx), wherein Bx is optionally a reaction product of a group 2 metal compound (MC) and a monohydric alcohol (B) in an organic liquid reaction medium, or a4) Type M (OR i ) n (OR2) m X 2-n-m Group 2 metal alkoxides, or M(OR) which are Group 2 metal alkoxides i ) n’ X 2-n’ and M(OR2) m’ X2-m’ This is a step of preparing a solution of a mixture with, where M is a Group 2 metal, X is a halogen, R1 and R2 are alkyl groups with different carbon atoms in C2~C 16 which are alkyl groups with different carbon atoms, 0≦n<2, 0≦m<2, and n+m+(2-n-m)=2, provided that m≠0, 0<n’≦2 and 0<m’≦2 are all satisfied, the step, and b) a step of contacting the solution from step a) with at least one compound (TC) of a transition metal compound of Groups 4 to 6, and c) a step of obtaining solid catalyst component particles, and Optionally, in any step before step c), a step of adding an internal electron donor (ID), preferably a non-phthalic acid internal electron donor (ID) It can be obtained by a method including.

[0082] The internal electron donor (ID) or its precursor is preferably added to the solution in step a) or the transition metal compound before contacting with the solution in step a).

[0083] According to the above procedure, the Ziegler-Natta catalyst can be obtained by a precipitation method or an emulsion solidification method according to physical conditions, particularly the temperature used in steps b) and c). In this application, an emulsion is also called a liquid / liquid two-phase system. In any method (precipitation or emulsion solidification), the chemical properties of the catalyst are the same.

[0084] In the precipitation method, the solution from step a) is combined with at least one transition metal compound (TC) in step b). The entire reaction mixture is maintained at a temperature of at least 50°C, more preferably in the range of 55 to 110°C, and more preferably in the range of 70 to 100°C to ensure that the catalyst components precipitate completely in the form of solid particles (step c). In the emulsification solidification method, the solution from step a) is typically added to at least one transition metal compound (TC) in step b) at a lower temperature, for example, -10 to less than 50°C, preferably -5 to 30°C. The temperature is typically maintained at -10 to less than 40°C, preferably -5 to 30°C, while the emulsion is being stirred. Droplets of the dispersed phase of the emulsion form the active catalyst composition. The solidification of the droplets (step c) is preferably carried out by heating the emulsion to a temperature of 70 to 150°C, preferably 80 to 110°C.

[0085] In a preferred embodiment, step a) uses a solution of a2) or a3), i.e., a solution of (Ax') or a solution of a mixture of (Ax) and (Bx), particularly the solution of a2). Preferably, the group 2 metal (MC) is magnesium.

[0086] The magnesium alkoxy compounds defined above can be prepared in situ in step a), which is the first step of the catalyst preparation method, by reacting the magnesium compound with an alcohol as described above. Alternatively, the magnesium alkoxy compounds can be magnesium alkoxy compounds prepared separately. Furthermore, these can be commercially available as ready-made magnesium alkoxy compounds and can be used as is in the catalyst preparation method of the present invention.

[0087] Exemplary examples of alcohol (A) are glycol monoethers. Preferred alcohol (A) are C2-C4 glycol monoethers, where the ether portion contains 2-18 carbon atoms, preferably 4-12 carbon atoms. Preferred examples include 2-(2-ethylhexyloxy)ethanol, 2-butyloxyethanol, 2-hexyloxyethanol, and 1,3-propylene glycol monobutyl ether and 3-butoxy-2-propanol, with 2-(2-ethylhexyloxy)ethanol, 1,3-propylene glycol monobutyl ether and 3-butoxy-2-propanol being particularly preferred.

[0088] An example monohydric alcohol (B) is of formula ROH, where R is a linear or branched C2-C2 group. 16 Alkyl residues, preferably C4-C 10 , more preferably C6-C8 alkyl residues. The most preferred monohydric alcohol is 2-ethyl-1-hexanol, or octanol. Preferably, a mixture of Mg alkoxy compounds (Ax) and (Bx), or a mixture of alcohols (A) and (B) is used, with a molar ratio of Bx:Ax or B:A of 10:1 to 1:10, more preferably 6:1 to 1:6, and most preferably 4:1 to 1:4.

[0089] Magnesium alkoxy compounds may be reaction products of the alcohols defined above with magnesium compounds selected from dialkylmagnesium, alkylmagnesium alkoxides, magnesium dialkoxides, alkoxymagnesium halides, and alkylmagnesium halides. Furthermore, magnesium dialkoxides, magnesium diaryl oxides, magnesium aryloxyhalides, magnesium aryl oxides, and magnesium alkylaryl oxides can be used. The alkyl group may be the same or different C1-C 20 Alkyl, preferably C2-C 10Alkyl magnesium compounds can be used. Typical alkylalkoxymagnesium compounds, when used, are ethylmagnesium butoxide, butylmagnesium pentoxide, octylmagnesium butoxide, and octylmagnesium octoxide. Dialkylmagnesium is preferred. The most preferred dialkylmagnesiums are butyloctylmagnesium or butylethylmagnesium.

[0090] Magnesium compounds are given by formula R"(OH) m It is also possible to obtain the magnesium alkoxide compound by reacting it with a polyhydric alcohol (C). When used, the preferred polyhydric alcohol is one in which R'' is linear, cyclic, or branched C2-C. 10 It is a hydrocarbon residue, and an alcohol in which m is an integer between 2 and 6.

[0091] Therefore, the magnesium alkoxy compound in step a) is selected from the group consisting of magnesium dialkoxide, diaryloxymagnesium, alkyloxymagnesium halide, aryloxymagnesium halide, alkylmagnesium alkoxide, arylmagnesium alkoxide, and alkylmagnesium aryloxide. In addition, a mixture of magnesium dihalide and magnesium dialkoxide can be used.

[0092] The solvent used in preparing the catalyst of the present invention may be selected from aromatic and aliphatic linear, branched, and cyclic hydrocarbons having 5 to 20 carbon atoms, more preferably 5 to 12 carbon atoms, or mixtures thereof. Suitable solvents include benzene, toluene, cumene, xylene, pentane, hexane, heptane, octane, and nonane. Hexane and pentane are particularly preferred. The reaction for preparing the magnesium alkoxy compound may be carried out at a temperature of 40 to 70°C. The most suitable temperature is selected depending on the Mg compound and alcohol used.

[0093] The transition metal compounds of groups 4 to 6 are preferably titanium compounds, most preferably titanium halides, such as TiCl4.

[0094] The internal donor (ID) used in the preparation of the catalyst used in the present invention is preferably selected from (di)esters, 1,3-diethers, derivatives and mixtures thereof of non-phthalate(di)carboxylic acids. Particularly preferred donors are diesters of monounsaturated dicarboxylic acids, and are esters belonging to the group that includes malonic acid esters, maleic acid esters, succinic acid esters, citraconic acid esters, glutaric acid esters, cyclohexene-1,2-dicarboxylic acid esters, and benzoic acid esters, as well as any derivatives and / or mixtures thereof. Preferred examples include, for example, substituted maleic acid esters and citraconic acid esters, most preferably citraconic acid esters.

[0095] In the emulsion method, a two-phase liquid-liquid system can be formed by simple stirring and optional addition of (further) solvents and additives, such as turbulence reducers (TMAs) and / or emulsifiers and / or emulsion stabilizers, such as surfactants, which are used as known to those skilled in the art to promote emulsion formation and / or stabilize the emulsion. Preferably, the surfactant is an acrylic or methacrylic polymer. Particularly preferred is an unbranched C 12 ~C 20 (Meth)acrylates, such as poly(hexadecyl) methacrylate and poly(octadecyl) methacrylate, and mixtures thereof. When used, the turbulence reducer (TMA) is preferably selected from α-olefin polymers of alpha-olefin monomers having 6 to 20 carbon atoms, such as polyoctene, polynonene, polydecene, polyundecene, or polydodecene, or mixtures thereof. Polydecene is the most preferred.

[0096] The Ziegler-Natta catalyst may also be in the form of particulate products, which may be washed at least once, preferably at least twice, and most preferably at least three times, with aromatic and / or aliphatic hydrocarbons, preferably toluene, heptane, or pentane, and / or TiCl4. The washing solution may also contain a donor and / or Group 13 compound, such as trialkylaluminum, alkylaluminum halide, or alkoxyaluminum compound. Aluminum compounds may also be added during catalyst synthesis. The catalyst can be further dried by evaporation or nitrogen flushing, or it can be slurryed into an oily liquid without any drying step.

[0097] The final Ziegler-Natta catalyst is preferably in the form of particles with an overall average particle size range of 5–200 μm, preferably 10–100 μm.

[0098] The particles are dense, have low porosity, and a surface area of ​​20 g / m². 2 Less than 10 g / m², more comfortably 10 g / m² 2 It is less than . Typically, the amount of Ti is 1 to 6% by mass of the catalyst composition, Mg is 10 to 20% by mass, and the donor is 10 to 40% by mass. Detailed descriptions of the preparation of the catalyst are disclosed in WO 2012 / 007430, EP2610271, EP2610270, and EP2610272, which are incorporated herein by reference.

[0099] Co-catalyst and external donor The Ziegler-Natta catalyst may be used in conjunction with an alkylaluminum cocatalyst and an external donor.

[0100] The co-catalyst is preferably a compound from Group 13 of the periodic table (IUPAC), such as organoaluminum, such as aluminum compounds, such as aluminum alkyl, aluminum halide, or aluminum alkyl halide. Therefore, in a particular embodiment, the co-catalyst (Co) is triallylaluminum, such as triallylaluminum (TEAL), dialkylaluminum chloride, or alkylaluminum dichloride, or a mixture thereof. In a particular embodiment, the co-catalyst (Co) is triallylaluminum (TEAL).

[0101] Advantageously, the triethylaluminum (TEAL) has a hydride content represented as AlH3 of less than 1.0% by mass relative to the triethylaluminum (TEAL). More preferably, the hydride content is less than 0.5% by mass, and most preferably, the hydride content is less than 0.1% by mass.

[0102] Suitable external donors (EDs) include certain silanes, ethers, esters, amines, ketones, heterocyclic compounds, and blends thereof. The use of silanes is particularly preferred. General formula: R a p R b q Si(OR c ) (4-p-q) It is most preferable to use the silane, where R a , R b , and R c R represents a hydrocarbon group, particularly an alkyl group or cycloalkyl group, where p and q are numbers in the range of 0 to 3, and their sum p+q is 3 or less. a , R b , and R c These can be chosen independently of each other and may be the same or different. Specific examples of such silanes include (tert-butyl)2Si(OCH3)2, (cyclohexyl)(methyl)Si(OCH3)2, (phenyl)2Si(OCH3)2, and (cyclopentyl)2Si(OCH3)2, or the general formula... Si(OCH2CH3)3(NR 3 R 4 ) It is of the form, and in the formula, R 3 and R 4 The two elements may be the same or different, and 'a' represents a hydrocarbon group having 1 to 12 carbon atoms.

[0103] R 3 and R 4 R is independently selected from the group consisting of linear aliphatic hydrocarbon groups having 1 to 12 carbon atoms, branched aliphatic hydrocarbon groups having 1 to 12 carbon atoms, and cyclic aliphatic hydrocarbon groups having 1 to 12 carbon atoms. 3 and R 4 However, it is particularly preferable that the element be independently selected from the group consisting of methyl, ethyl, n-propyl, n-butyl, octyl, decanyl, isopropyl, isobutyl, isopentyl, tert-butyl, tert-amyl, neopentyl, cyclopentyl, cyclohexyl, methylcyclopentyl, and cycloheptyl.

[0104] Particularly preferred external donors (EDs) are pentyl dimethoxysilandonner (D-donor) or cyclohexylmethyl dimethoxysilandonner (C-donor).

[0105] Preferably, the ratio of co-catalyst (Co) to external donor (ED) [Co / ED] and / or the ratio of co-catalyst (Co) to transition metal (TM) [Co / TM] should be carefully selected.

[0106] Therefore, the molar ratio of the co-catalyst (Co) to the external donor (ED) [Co / ED] must be in the range of 5 to 45, preferably in the range of 5 to 35, more preferably in the range of 5 to 25, and optionally, the molar ratio of the co-catalyst (Co) to the titanium compound (TC) [Co / TC] must be in the range of over 80 to 500, preferably in the range of 100 to 350, and even more preferably in the range of 120 to 300.

[0107] Polymerization of propylene As described above, this disclosure also relates to a method for producing a propylene polymer. The method comprises the step of polymerizing propylene in the presence of a prepolymerization Ziegler-Natta catalyst as described herein.

[0108] The polymerization of propylene may be carried out in a separate reactor and / or reaction medium using a prepolymerization Ziegler-Natta catalyst. For example, after the prepolymerization Ziegler-Natta catalyst has formed, at least a portion of the catalyst slurry may be recovered, optionally stored, and used to catalyze the propylene polymerization reaction in a separate reactor or reaction medium.

[0109] Propylene polymerization may be carried out in the presence of a co-catalyst and / or an external donor. The co-catalyst and / or external donor used may be the same as or different from any co-catalyst and / or external donor used to produce the prepolymerized Ziegler-Natta catalyst. In some examples, for example, when the prepolymerized Ziegler-Natta catalyst is recovered and introduced into another reactor or reaction medium, additional co-catalysts and additional external donors are used together with the prepolymerized Ziegler-Natta catalyst. These additional co-catalysts and external donors may be the same as or different from the co-catalysts and external donors used to produce the prepolymerized Ziegler-Natta catalyst.

[0110] Propylene may be polymerized in any preferred manner in the presence of a prepolymerization Ziegler-Natta catalyst. In some examples, propylene is used as the sole monomer. In other examples, propylene is used as one or more comonomers, e.g., C2 or C4-C2. 10 Copolymerize with olefins.

[0111] The apparatus used for propylene polymerization can be equipped with any polymerization reactor suitable for producing propylene homopolymers or copolymers. From this viewpoint, polymerization is carried out in one or more polymerization reactors. Preferably, the polymerization reactor system can be equipped with one or more conventional stirred-tank slurry reactors, one or more gas-phase reactors, or a combination thereof.

[0112] In the present invention, “slurry reactor” means any reactor operated with bulk or slurry in which the polymer is formed in particulate form, such as a continuous or simple batch stirred tank reactor or loop reactor. “Bulk” means polymerization in a reaction medium containing at least 60% by mass of monomer. According to a preferred embodiment, the slurry reactor comprises a loop reactor. “Gas-phase reactor” means any reactor that is mechanically mixed or a fluidized bed. Preferably, the gas-phase reactor comprises a mechanically stirred fluidized bed reactor with a gas velocity of at least 0.2 m / sec. In one embodiment, polymerization may be carried out in at least one gas-phase reactor.

[0113] The gas-phase reactor can be a conventional fluidized bed reactor, but other types of gas-phase reactors can also be used. In a fluidized bed reactor, the bed consists of polymer particles that form and grow, and a still-active catalyst associated with polymer fractionation. The bed is kept fluid by introducing a gaseous component, such as a monomer, at a flow rate that allows the particles to act as a fluid. The fluidizing gas may include an inert carrier gas, such as nitrogen, and also hydrogen as a polymer molecular weight control agent. The fluidized gas-phase reactor may be equipped with a mechanical mixer. The gas-phase reactor used can be operated at a temperature range of 50 to 100°C, preferably 65 to 90°C, a reaction pressure of 10 to 40 bar, and a monomer partial pressure of 15 to 30 bar. The polymerization temperature in the loop reactor is typically 50 to 110°C, preferably 60 to 100°C, particularly 65 to 95°C. The pressure is 1 to 150 bar, preferably 10 to 100 bar.

[0114] In another embodiment, polymerization is carried out in at least two polymerization reactors selected from slurry loops and gas-phase reactors, and combinations thereof. This embodiment is particularly suitable for producing multi-(bi)modulated polypropylene. Several reactors of each type can be used, for example, one loop reactor and two or three gas-phase reactors in series. A preferred embodiment of the present invention includes a cascaded loop and gas-phase reactor, and involves carrying out polymerization in a process in which the loop reactor is operated with liquid propylene.

[0115] In addition to the actual polymerization reactor used to produce propylene homopolymers or copolymers, the polymerization reaction system may also include several additional reactors, such as pretreatment and / or posttreatment reactors.

[0116] The term "propylene polymer" will be understood to encompass propylene homopolymers (H-PP) and / or propylene copolymers (C-PP). Furthermore, the term "propylene copolymer" will encompass propylene random copolymers, heterophase polymers, and mixtures thereof. In one preferred embodiment, a prepolymerization solid Ziegler-Natta catalyst is used to produce a propylene homopolymer or a propylene random copolymer. In another embodiment, a prepolymerization solid Ziegler-Natta catalyst is used to produce a propylene homopolymer. The expression propylene homopolymer (H-PP) as used throughout the present invention relates to a propylene polymer consisting substantially of propylene units, i.e., more than 99.5% by mass, more preferably at least 99.7% by mass, for example at least 99.8% by mass of propylene units. In one preferred embodiment, only propylene units are detectable in the propylene homopolymer (H-PP).

[0117] Additionally or alternatively, the propylene polymer is a propylene copolymer (C-PP). In one embodiment, the propylene homopolymer can be further polymerized in the presence of ethylene and optionally C4-C8 alpha-olefins to obtain an elastomer propylene copolymer (E), for example, a heterophase propylene copolymer. In some examples, an advantage of implementing a prepolymerization solid Ziegler-Natta catalyst in a method for producing a propylene polymer is that the powder form of the resulting propylene polymer is improved (compared to propylene polymers prepared using the same solid Ziegler-Natta catalyst without batch-mode prepolymerization).

[0118] Properties of polypropylene Using the prepolymerization Ziegler-Natta catalyst described herein, polypropylene compositions with improved properties can be produced.

[0119] For example, the melt flow rate (MFR2) of propylene polymer, measured according to ISO 1133 (230°C, 2.16 kg), can be in a wide range, e.g., 0.15 to 1000 g / 10 min, depending on the desired properties of the end application.

[0120] The crystallization temperature of the propylene polymer is at least 115°C, preferably 115-145°C, more preferably 120-140°C, and even more preferably 122-137°C, for example, 126-135°C.

[0121] The enthalpy of melt of the propylene polymer can be at least 90 J / g, preferably 95 to 160 J / g, more preferably 103 to 150 J / g, for example, 115 to 130 J / g.

[0122] The propylene polymer may have a tensile modulus of at least 1800 MPa, preferably 1900 to 3000 MPa, and more preferably 2190 to 2400 MPa, according to ISO 527-2.

[0123] Propylene polymers obtained by methods for producing propylene polymers can be pelletized and blended using any of the various well-known compounding and blending methods commonly used in resin compounding technology.

[0124] The present invention will be further explained below with reference to examples. [Examples]

[0125] Measurement method The following definitions of terms and measurement methods apply to the general description of the present invention above and the following examples, unless otherwise specified.

[0126] MFR2 (230℃ / 2.16kg) is measured in accordance with ISO 1133 at 230℃ and with a load of 2.16kg.

[0127] The melting point (Tm), enthalpy of fusion (Hm), and crystallization temperature (Tc) were measured using a TA Instrument Q200 differential scanning calorimeter (DSC) on 5-7 mg samples. DSC was performed according to ISO 11357 / Part 3 / Method C2, using a scan speed of 10°C / min in the temperature range of -30 to +225°C, with a heating / cooling / heating cycle. The crystallization temperature (Tc) was determined from the cooling step, while the melting temperature (Tm) and enthalpy of fusion (Hm) were determined from the second heating step.

[0128] Tensile properties (tensile modulus, tensile strength, strain at tensile strength, tensile stress at fracture, and tensile strain at fracture) were determined using a 1A dogbone according to ISO 527-2. As per the standard, a test speed of 1 mm / min was used for tensile modulus and 50 mm / min for all other properties. The test temperature was 23±2°C. Injection molding was performed according to ISO 19069-2.

[0129] (Example 1) a. Preparation of prepolymerization Ziegler-Natta catalyst (Catalyst 1) A commercially available Ziegler-Natta catalyst was dispersed in oil to form a slurry. First, the catalyst oil slurry (13 kg, 3 kg of dry catalyst, Ti content 1.79 mass%) was supplied to a reactor equipped with a stirrer and a heating / cooling jacket. The reactor temperature was set to 25°C and the stirring speed to 140 rpm. Next, oil was added (23 kg) to dilute the slurry to approximately 7 mass%. After the addition of oil, triethylaluminum (TEAL) (100%, 452 g) was added to activate the catalyst (Al / Ti ratio 3.5 mol / mol). After stirring for 10 minutes, internal donor Do (258 g) was added (Al / Do ratio 3.5 mol / mol).

[0130] 1-Butene was added using a measuring cylinder while controlling the temperature to below 25°C. A total of 3.3 kg of 1-butene was supplied over 2.5 hours, ensuring that the pressure and temperature in the reactor were maintained at the desired levels. After confirming the consumption of butene by stabilizing the pressure in the reactor, the next addition was made. After the addition, the 1-butene was reacted for 2 hours while maintaining the temperature at 25°C. The reaction mixture was stirred at 140 RPM.

[0131] After 2 hours, the reactor pressure was reduced to 1 bar (g), and the reactor temperature was increased to 60°C while vinylcyclohexane (VCH, CAS number 695-12-5) (3 kg) was supplied to the reactor at a rate of 60 g / min. After the introduction of VCH, the VCH was reacted at 60°C for 16 hours. After 16 hours, a sample was taken and the unreacted VCH content was analyzed by gas chromatography (GC). Since the result was lower than 1000 ppm (24 ppm), a batch of pre-polymerized Ziegler-Natta catalyst (catalyst 1) was recovered from the reactor and used for the propylene polymerization described below. The final calculated value of the Ziegler-Natta catalyst content in the slurry was 7.6 mass%.

[0132] b. Propylene polymerization using catalyst 1 Propylene polymerization was carried out in a 5-liter jacketed stainless steel reactor. 139.3 mg of triethylaluminum (TEAL) (Chemtura, used as received) was added as a co-catalyst, 27.6 mg of dicyclopentyl dimethoxysilane (DCDS) (Wacker, dried using molecular sieve) was added as an external donor, and 15 ml of n-pentane was mixed and reacted for 5 minutes. This mixture was added to a polymerization reactor at 20°C. Next, 200 mmol of hydrogen and 1360 g of propylene were added to the reactor.

[0133] Polymerization was initiated by introducing a catalyst / oil mixture (172.0 mg of the oil / catalyst mixture recovered in Example 1a above, mixed with 6 ml of additional oil) into a reactor flushed with propylene (35 g) (total amount of propylene: 1395 g). The amount of dry catalyst was 13.1 mg. The Al / Ti ratio was 250 mol / mol, and the Al / DCDS ratio was 10 mol / mol.

[0134] After pre-polymerization at 20°C for 15 minutes, the reactor temperature was increased to the polymerization temperature (80°C) over approximately 15 minutes. The polymerization time after reaching the polymerization temperature was 60 minutes. The exhaust valve was then opened to flush out unreacted propylene, and the reactor was cooled to room temperature. After flushing the reactor several times with nitrogen, the polymer was collected, dried overnight, and then weighed to record the polymer yield (322g).

[0135] (Comparative Example 1) a. Preparation of prepolymerization Ziegler-Natta catalyst (catalyst C1) Catalyst C1 was prepared in the same manner as Catalyst 1 in Example 1, but with slight adjustments to the Al / Ti and Al / Do ratios (1 mol / mol and 0.75 mol / mol, respectively). Vinylcyclohexane (VCH) was not added to the catalyst preparation, but the catalyst preparation was considered complete after a 2-hour reaction with 1-butene. This batch of pre-polymerized Ziegler-Natta catalyst (Catalyst C1) was removed from the reactor and used in the propylene polymerization described below.

[0136] b. Propylene polymerization using catalyst C1 Propylene polymerization was carried out in a 5-liter jacketed stainless steel reactor. 143.4 mg of triethylaluminum (TEAL) (Chemtura, used as received) was used as a co-catalyst, 28.6 mg of dicyclopentyl dimethoxysilane (DCDS) (Wacker, dried using molecular sieving) was used as an external donor, and 15 ml of n-pentane was mixed and reacted for 5 minutes. This mixture was added to a polymerization reactor at 20°C. Next, 200 mmol of hydrogen and 1360 g of propylene were added to the reactor. Polymerization was initiated by introducing a catalyst / oil mixture (174.7 mg of oil / catalyst mixture containing catalyst C1 recovered from Comparative Example 1a, mixed with 6 ml of additional oil) into a reactor flushed with propylene (35 g) (total amount of propylene: 1395 g). The amount of dry catalyst was 13.5 mg. The Al / Ti ratio was 250 mol / mol, and the Al / DCDS ratio was 10 mol / mol. After pre-polymerization at 20°C for 15 minutes, the reactor temperature was increased to the polymerization temperature (80°C) over approximately 15 minutes. The polymerization time after reaching the polymerization temperature was 60 minutes. The exhaust valve was then opened to flush out unreacted propylene, and the reactor was cooled to room temperature. After flushing the reactor several times with nitrogen, the polymer was collected, dried overnight, and then weighed to record the polymer yield (279 g).

[0137] (Comparative Example 2) a. Preparation of prepolymerization Ziegler-Natta catalyst (catalyst C2) A slurry was formed by dispersing the same commercially available Ziegler-Natta catalyst used in Example 1 and Comparative Example 2 in oil. The catalyst oil slurry (21.5 kg, 5 kg dry catalyst) was supplied to a reactor equipped with a stirrer and a heating / cooling jacket. The reactor temperature was set to 15°C and the slurry was stirred at 140 rpm. More oil was added (13.9 kg) to dilute the slurry to approximately 12% by mass. After the addition of oil, TEAL (100%, 750 g) was added to activate the catalyst (Al / Ti ratio 3.5 mol / mol). After stirring for 10 minutes, D-donor (430 g) was added (Al / Do ratio 3.5 mol / mol). VCH feed (5 kg) was added at approximately 60 g / min, and at the same time, the reactor temperature was increased to 60°C. After the supply of VCH, the VCH was reacted at 60°C for a further 10 hours. After 10 hours, a sample was taken and the unreacted VCH content was analyzed by gas chromatography (GC). Since the result was less than 1000 ppm (110 ppm), the batch was recovered and used for propylene polymerization as described below.

[0138] b. Propylene polymerization using catalyst C2 Propylene polymerization was carried out in a 5-liter jacketed stainless steel reactor. 159.3 mg of triethylaluminum (TEAL) (Chemtura, used as received) was used as a co-catalyst, 31.5 mg of dicyclopentyl dimethoxysilane (DCDS) (Wacker, dried using a molecular sieve) was used as an external donor, and 15 ml of n-pentane was mixed and reacted for 5 minutes. This mixture was added to a polymerization reactor at 20°C. Next, 200 mmol of hydrogen and 1360 g of propylene were added to the reactor. Polymerization was initiated by introducing a catalyst / oil mixture (123.8 mg of the oil / catalyst mixture recovered in Comparative Example 2a above, mixed with 10 ml of additional oil) into a reactor flushed with propylene (35 g) (total amount of propylene: 1395 g). The amount of dry catalyst was 14.9 mg. The Al / Ti ratio was 250 mol / mol, and the Al / DCDS ratio was 10 mol / mol. After pre-polymerization at 20°C for 15 minutes, the reactor temperature was increased to the polymerization temperature (80°C) for approximately 15 minutes. The polymerization time after reaching the polymerization temperature was 60 minutes. The exhaust valve was then opened to flush out unreacted propylene, and the reactor was cooled to room temperature. After flushing the reactor several times with nitrogen, the polymer was collected, dried overnight, and then weighed to record the polymer yield (501 g).

[0139] Table 1 summarizes the properties of the polypropylene produced in Example 1b, Comparative Example 1b, and Comparative Example 2b. The polypropylene samples from Example 1b, Comparative Example 1b, and Comparative Example 2b are denoted as IE1, CE1, and CE2, respectively.

[0140] The crystallization temperature is a good indicator of how effectively polypropylene nucleated. A higher Tc indicates more effective nucleation. From Table 1, it can be seen that the IE1 Ziegler-Natta prepolymerization catalyst has the highest Tc and the highest Hm. Its tensile modulus is also higher than that of the comparative example.

[0141] [Table 1]

Claims

1. A method for producing a prepolymerized Ziegler-Natta catalyst composition, A step of reacting at least one acyclic alpha-olefin having 2 to 10 carbon atoms in the presence of a Ziegler-Natta catalyst, and Aii) A step of subsequently reacting vinylcycloalkanes, vinylcycloalkenes, and / or vinylarenes in the presence of a Ziegler-Natta catalyst; or A step of reacting a vinylcycloalkane, vinylcycloalkene, and / or vinylarene in the presence of a Ziegler-Natta catalyst, and Bii) Subsequently, a step of reacting at least one acyclic alpha-olefin having 2 to 10 carbon atoms in the presence of a Ziegler-Natta catalyst. Includes, A method comprising: Bi) reacting vinylcycloalkanes, vinylcycloalkenes, and / or vinylarenes in the presence of a Ziegler-Natta catalyst; and Bi) subsequently reacting at least one acyclic alpha-olefin having 2 to 10 carbon atoms in the presence of a Ziegler-Natta catalyst, wherein the mass ratio of at least one acyclic alpha-olefin to the Ziegler-Natta catalyst is less than 200:

1.

2. A step of reacting at least one acyclic alpha-olefin having 2 to 8 carbon atoms, preferably 2 to 6 carbon atoms, in the presence of a Ziegler-Natta catalyst, and Aii) The process of reacting vinylcycloalkanes, vinylcycloalkenes, and / or vinylarenes in the presence of a Ziegler-Natta catalyst. The method according to claim 1, including the method described in claim 1.

3. The method according to claim 1, wherein the acyclic alpha-olefin is selected from ethylene, propylene, 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, and any combination thereof, preferably the acyclic alpha-olefin is selected from ethylene, propylene, 1-butene, 1-pentene, 1-hexene, 1-heptene, and 1-octene, and more preferably the acyclic alpha-olefin is 1-butene.

4. The method according to any one of claims 1 to 3, wherein in step Aii), a vinylcycloalkane, preferably vinylcyclohexane, is reacted in the presence of a Ziegler-Natta catalyst, or in step Bi), a vinylcycloalkane, preferably vinylcyclohexane, is reacted in the presence of a Ziegler-Natta catalyst.

5. The method according to any one of claims 1 to 4, wherein in step Ai), the mass ratio of at least one acyclic alpha-olefin to the Ziegler-Natta catalyst is less than 200:

1.

6. The method according to claim 5, wherein in step Ai) or step Bi), the mass ratio of at least one acyclic alpha-olefin to the Ziegler-Natta catalyst is less than 100:1, preferably 10:90 to 90:10, more preferably 20:80 to 80:20, even more preferably 30:70 to 70:30, still more preferably 40:60 to 60:40, and even more preferably 45:55 to 55:

45.

7. The method according to any one of claims 1 to 6, wherein in step Ai) or step Bii), the mass ratio of vinylcycloalkane, vinylcycloalkene, and / or vinylarene to the Ziegler-Natta catalyst is less than 200:1, preferably less than 100:1, more preferably 10:90 to 90:10, not less preferably 20:80 to 80:20, even more preferably 30:70 to 70:30, even more preferably 40:60 to 60:40, and even more preferably 45:55 to 55:

45.

8. The method according to any one of claims 1 to 7, wherein the Ziegler-Natta catalyst comprises a transition metal compound selected from groups 4 to 6 of the periodic table, a group 1 to 3 metal compound, and an internal donor.

9. The method according to claim 8, wherein the Ziegler-Natta catalyst comprises a titanium compound, a magnesium compound, and an internal donor.

10. The method according to any one of claims 1 to 9, wherein at least one of steps Ai) and Aii), or at least one of steps Bi) and Biii), is carried out in the presence of a cocatalyst and an external donor.

11. The method according to any one of claims 1 to 10, wherein the prepolymerization Ziegler-Natta catalyst composition comprises a Ziegler-Natta catalyst, a polymer having polymerization units derived from at least one acyclic alpha-olefin having 2 to 10 carbon atoms, and a polymer having polymerization units derived from vinylcycloalkane, vinylcycloalkene, and / or vinylarene.

12. A prepolymerized solid Ziegler-Natta catalyst composition that can be obtained by the method described in any one of claims 1 to 11.

13. A catalyst system for the polymerization of propylene, comprising the prepolymerization Ziegler-Natta catalyst composition, co-catalyst, and external donor described in claim 12.

14. A method for producing polypropylene, comprising the step of polymerizing propylene in the presence of the prepolymerization Ziegler-Natta catalyst composition according to claim 12.

15. The method according to claim 14, wherein the prepolymerized Ziegler-Natta catalyst composition forms part of the catalyst system according to claim 13.

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