Method for producing propylene-based block copolymer

Abstract

Provided is a method for producing a propylene-based block copolymer, the method including: a first polymerization step for producing a first propylene-based polymer having a propylene content of more than 95 mass% in the presence of a catalyst comprising an olefin polymerization catalyst component (A) and an organoaluminum compound (B) using one or more reactors; and a second polymerization step for producing a second propylene-based polymer, the second polymerization step including a step in which a copolymer with at least one monomer selected from the group consisting of α-olefins excluding propylene is polymerized in the presence of the first propylene-based polymer using one or more reactors including horizontal reactors, wherein the propylene content in the resultant copolymer is 95 mass% or less. The second polymerization step includes supplying an electron-donating compound that has a liquid form in the standard state thereof to a final horizontal reactor at any region from the most downstream end in the longitudinal direction of the final horizontal reactor to 66% in the upstream direction. In the second polymerization step, the oxygen concentration in each of the reactors is less than 0.60 mol ppm.

Description

Method for Propylene Block Copolymer Production

[0001] This invention relates to a method for producing propylene-based block copolymers.

[0002] Crystalline polypropylene, obtained by polymerizing propylene under stereoregular catalysis, is widely used among thermoplastic resins due to its lightweight nature, excellent rigidity and heat resistance, and ease of recycling. On the other hand, to improve the impact resistance, which is a drawback of crystalline polypropylene, a widely known method involves producing crystalline polypropylene in the first polymerization step and then copolymerizing propylene with other α-olefins in the subsequent polymerization step to create a propylene-α-olefin copolymer, thereby producing a propylene-based block copolymer.

[0003] However, in continuous polymerization methods for stepwise polymerization, a distribution occurs in the polymerization time (residence time in the reactor) of the catalyst component in the reactor of the first-stage polymerization step. When polymer particles discharged from the first-stage polymerization step in a relatively short time (short-pass polymer particles) enter the reactor of the second-stage polymerization step, polymer particles with a high propylene-α-olefin copolymer content are generated. Such polymer particles do not disperse even by kneading, causing gels and fish eyes, which impair the appearance of the product and reduce its mechanical strength.

[0004] Furthermore, while increasing the proportion of copolymer in the second polymerization step is effective in increasing the impact strength of propylene-based block copolymers, a higher proportion of copolymer makes it easier for even ordinary particles that have not passed through the short-pass process to adhere to the reactor walls and other surfaces. Once these particles are formed, insufficient heat removal can lead to the formation of polymer clumps, which can disrupt operation. Additionally, increased stickiness of the polymer particles worsens their fluidity, hindering their removal from the reactor and transfer.

[0005] To reduce the formation of gels and fish eyes caused by such short-pass polymer particles, and to reduce the adhesion of polymer particles with a high copolymer content, a method of adding an electron-donating compound to the second-stage polymerization step has been proposed (Patent Documents 1-3). Furthermore, Patent Document 4 discloses a method for producing a propylene-ethylene-based block copolymer containing a propylene-ethylene-based copolymer in a multi-stage continuous polymerization method while reducing gel without unnecessarily increasing the number of reactors and with high catalytic efficiency. This method involves supplying an electron-donating mixture, which is a mixture of a specific polyoxyalkylene-based compound and a specific alcohol compound, to the gas-phase polymerization reactor in the second step as a mixed stream with liquefied propylene in a specific ratio.

[0006] Japanese Patent Publication No. 2008-150465, Japanese Patent Publication No. 2008-150466, Japanese Patent Publication No. 2011-84612, Japanese Patent Publication No. 2022-14443

[0007] The effect of adding electron-donating compounds is estimated to be as follows: The added electron-donating compounds selectively act on polymerization active sites relatively close to the surface of polymer particles, deactivating these active sites. However, because short-pass polymer particles have a small particle size and are easily deactivated, they are selectively deactivated even at addition amounts that would not completely deactivate polymer particles of normal particle size. Furthermore, because the active sites on the surface of normal polymer particles are selectively deactivated, copolymers are formed internally, and even if the copolymer content increases, the increase in surface adhesion is relatively suppressed. While these methods show a certain effect in suppressing deposits compared to not adding electron-donating compounds, further technological improvements were desired. It was also desired that the odor of the resulting propylene-based block copolymer be suppressed.

[0008] In view of the problems of the prior art described above, the object of the present invention is to provide a method for producing a propylene-based block copolymer in which gel and fish eyes are reduced and odor is suppressed.

[0009] The present inventors, after diligent research to solve the above problems, have found that the above problems can be solved in a method for producing a propylene-based block copolymer comprising a first polymerization step and a second polymerization step using a specific catalyst, by supplying an electron-donating compound, which is liquid at standard conditions, to any point between the furthest downstream end in the longitudinal direction of the final horizontal reactor in the second polymerization step and 66% upstream, thereby bringing the polymer in the reactor into contact with the electron-donating compound, which is liquid at standard conditions, and by setting the concentration of a polymerization activity inhibitor, which is gaseous at standard conditions, in the reactor in the second polymerization step to less than 0.60 mol ppm, and have completed the present invention. That is, the present invention includes the following aspects.

[0010] <1> A first polymerization step to produce at least one first propylene polymer (provided that the propylene content of the first propylene polymer exceeds 95% by mass) selected from a propylene homopolymer and a copolymer of propylene and at least one monomer selected from the group consisting of α-olefins other than propylene, using one or more reactors in the presence of a catalyst containing an olefin polymerization catalyst component (A) and an organoaluminum compound (B); and a second polymerization step to produce a second propylene polymer, using one or more reactors including a horizontal reactor, in the presence of the first propylene polymer, by polymerizing a copolymer of a propylene content of 95% by mass or less and at least one monomer selected from the group consisting of α-olefins other than propylene, wherein the second polymerization step includes supplying an electron-donating compound, which is liquid at standard conditions, to the final horizontal reactor at any point between the furthest downstream end in the longitudinal direction of the final horizontal reactor and 66% upstream. A method for producing a propylene-based block copolymer, wherein in the second polymerization step, the oxygen concentration in the reactor is less than 0.60 mol ppm. <2> The method for producing a propylene-based block copolymer according to <1>, wherein in the second polymerization step, an electron-donating compound that is liquid at standard conditions is supplied into the reactor at any point between the furthest downstream end in the longitudinal direction of the final horizontal reactor and 50% upstream. <3> The method for producing a propylene-based block copolymer according to <1>, wherein in the second polymerization step, an electron-donating compound that is liquid at standard conditions is supplied into the reactor at any point between the furthest downstream end in the longitudinal direction of the final horizontal reactor and 34% upstream. <4> The method for producing a propylene-based block copolymer according to any one of <1> to <3>, wherein the amount of the electron-donating compound that is liquid at standard conditions supplied in the second polymerization step is 0.5 to 20 times the molar amount of the organoaluminum compound (B) in the first polymerization step. <5> The method for producing a propylene-based block copolymer according to any one of <1> to <4>, wherein the electron-donating compound that is liquid under standard conditions is at least one compound selected from the group consisting of methanol, ethanol, isopropyl alcohol, acetone, and methyl acetate.<6> A method for producing a propylene-based block copolymer according to any one of <1> to <5>, wherein at least one of the first polymerization step and the second polymerization step is a gas-phase polymerization step. <7> A method for producing a propylene-based block copolymer according to <6>, wherein the gas-phase polymerization step is a gas-phase polymerization step in which the reaction heat is removed mainly by the heat of vaporization of liquefied propylene. <8> A method for producing a propylene-based block copolymer according to any one of <1> to <7>, wherein the propylene-based block copolymer produced is odorless in a sensory test. <9> A method for producing a propylene-based block copolymer according to any one of <1> to <8>, wherein the total amount of alcohol components having 4 or more carbon atoms in the propylene-based block copolymer produced by gas chromatography analysis is 6 ng or less per 1 g of propylene-based block copolymer.

[0011] According to the present invention, it is possible to provide a method for producing propylene-based block copolymers in which gel and fish eyes are reduced and odor is suppressed.

[0012] Figure 1 is a schematic diagram showing an example of the layout of a continuous horizontal gas-phase reactor. Figure 2 is a schematic diagram showing an example of a horizontal reactor used in the second polymerization process.

[0013] The present invention provides a method for producing a propylene-based block copolymer, comprising: a first polymerization step of producing at least one first propylene-based polymer (provided that the propylene content of the first propylene-based polymer exceeds 95% by mass) selected from a propylene homopolymer and a copolymer of propylene and at least one monomer selected from the group consisting of α-olefins other than propylene, using one or more reactors in the presence of a catalyst containing an olefin polymerization catalyst component (A) and an organoaluminum compound (B); and a second polymerization step of producing a second propylene-based polymer, comprising polymerizing a copolymer of a propylene content of 95% by mass or less and at least one monomer selected from the group consisting of α-olefins other than propylene, using one or more reactors including a horizontal reactor, in the presence of the first propylene-based polymer, wherein the second polymerization step includes supplying an electron-donating compound, which is liquid at standard conditions, to the final horizontal reactor at any point between the furthest downstream end in the longitudinal direction of the final horizontal reactor and 66% upstream. The second polymerization step is characterized in that the oxygen concentration in the reactor is less than 0.60 mol ppm.

[0014] The present invention provides a method for producing a propylene-based block copolymer, comprising: a first polymerization step in which a first propylene-based polymer having a propylene content exceeding 95% by mass is produced using a specific catalyst; and a subsequent second polymerization step in which a copolymer of a propylene content of 95% by mass or less and at least one monomer selected from the group consisting of α-olefins other than propylene is polymerized in the presence of the first propylene-based polymer using one or more reactors, including a horizontal reactor, to produce a second propylene-based polymer. In the present invention, in the second polymerization step, an electron-donating compound that is liquid at standard conditions is supplied to the final horizontal reactor at any point between the furthest downstream end in the longitudinal direction of the final horizontal reactor and 66% upstream, and in the second polymerization step, the oxygen concentration in the reactor is adjusted to less than 0.60 mol ppm, thereby suppressing a decrease in catalyst activity, reducing gel and fish eyes, and suppressing odor, thereby producing a propylene-based block copolymer. In the second polymerization step, by supplying an electron-donating compound, which is liquid at standard conditions, to any point between the furthest downstream end of the final horizontal reactor and 66% upstream in the longitudinal direction, without adding oxygen, the electron-donating compound can be more dispersed throughout the polymer group, enabling efficient deactivation of short-pass polymer particles and suppressing the generation of alcohol components with four or more carbon atoms, which are odor-causing substances. This results in improved odor compared to conventional propylene-based block copolymers. Furthermore, since the manufacturing method of the present invention yields propylene-based block copolymers with reduced gel and fish-eye properties, it is possible to obtain injection-molded and extruded products with excellent appearance. In addition, because there is less generation of alcohol components with four or more carbon atoms, which are odor-causing substances, it becomes possible to supply propylene-based block copolymers with stable quality in fields such as food and medicine. Furthermore, in the second polymerization step, by supplying an electron-donating compound, which is liquid at standard conditions, to any point between the furthest downstream end of the final horizontal reactor and 66% upstream in the longitudinal direction, without adding oxygen, the effect of suppressing deposits on the stirring blades and walls that tend to form downstream is enhanced, and quality deterioration due to the detachment of deposits during operation can be suppressed.

[0015] The embodiments of the present invention will be described in detail below, but the description of the constituent elements described below is just one example of an embodiment of the present invention, and the present invention is not limited to the following description unless it exceeds the gist of the invention. In this specification, the "~" indicating a numerical range is used to mean that the numerical values ​​described before and after it are included as the lower limit and upper limit. In this specification, "gel" refers to a bright spot that appears on a sheet or injection-molded piece of propylene-based block copolymer, and "fish eye" refers to a spherical defect that resembles a fish's eye that appears on a film or the like that extruded from propylene-based block copolymer. Although gel and fish eye are called by different names due to differences in the molding method of propylene-based block copolymer, both are generated by unmelted or undispersed material during molding, so propylene-based block copolymers in which gel generation is reduced also have reduced fish eye generation. Below, the catalyst used in the first polymerization step will be described first, and then each polymerization step will be described.

[0016] I. Catalyst The catalyst used in the present invention comprises an olefin polymerization catalyst component (A) and an organoaluminum compound (B). There are no particular restrictions on the catalyst, and various known catalysts can be used. Examples of these catalysts include Ziegler-Natta catalysts containing a solid catalyst component prepared using a trivalent or tetravalent titanium halide, alkoxytitanium, or alkoxytitanium halide and magnesium chloride or alkoxymagnesium as the olefin polymerization catalyst component, and metallocene catalysts containing a metallocene compound, such as a titanium, zirconium, or hafnium compound having a cyclopentadienyl group, as the olefin polymerization catalyst component.

[0017] 1. Olefin Polymerization Catalyst Component (A) (Ziegler-Natta Catalyst) An example of an olefin polymerization catalyst component (A) that is a Ziegler-Natta catalyst is a solid catalyst component comprising: component (a1): a solid component containing titanium, magnesium, halogen, and an electron donor as essential components; component (a2): a silane compound having an alkenyl group; component (a3): an alkoxysilane compound [however, this is different from a silane compound having an alkenyl group]; and component (a4): an organoaluminum compound as essential components. Here, "contained as essential components" means that other elements suitable for the purpose may be included in addition to the listed components, these elements may each exist as arbitrary compounds suitable for the purpose, and these elements may exist as being bonded to each other.

[0018] 1-1. Component (a1) Component (a1) is a solid component containing titanium, magnesium, halogen, and an electron donor as essential components.

[0019] 1-1-1. Any titanium compound can be used as the titanium source for the titanium solid component. A typical example is the compound disclosed in Japanese Patent Publication No. 3-234707. Regarding the valency of titanium, titanium compounds with any valency of tetravalent, trivalent, divalent, or 0valent can be used, preferably tetravalent or trivalent titanium compounds, and more preferably tetravalent titanium compounds.

[0020] Examples of tetravalent titanium compounds include titanium halides such as titanium tetrachloride and titanium tetrabromide, alkoxy titaniums such as tetraethoxytitanium and tetrabutoxytitanium, and tetrabutoxytitanium dimer (BuO). ３ Ti-O-Ti (OBu) ３ Examples include condensed compounds of alkoxytitanium having Ti-O-Ti bonds, organotitaniums such as dicyclopentadienyltitanium dichloride, and compounds whose average composition formula is a mixture of the above titanium compounds (for example, Ti(OBu) ｍ Cl ４－ｍ; (0 < m < 4), a complex of the above titanium compound and a phthalic acid ester or other compound (for example, Ph(CO ２ Bu) ２ ·TiCl ４ ) may also be used. Examples of the trivalent titanium compound include titanium halides such as titanium trichloride. As titanium trichloride, those produced by any known method such as hydrogen reduction type, metal aluminum reduction type, metal titanium reduction type, and organoaluminum reduction type can be used. Among the above titanium compounds, titanium tetrachloride and tetrabutoxy titanium are preferred. The above titanium compounds may be used alone or in combination of two or more.

[0021] 1-1-2. Magnesium As a magnesium source of magnesium contained in the solid component, metallic magnesium or any magnesium compound can be used. Representative examples include the compounds disclosed in JP-A-3-234707. Examples of the magnesium compound include magnesium halides such as magnesium chloride and magnesium bromide, inorganic magnesium compounds such as magnesium oxide and magnesium hydroxide, Grignard compounds such as ethyl magnesium chloride, butyl magnesium chloride, butyl magnesium bromide, and phenyl magnesium bromide, alkoxy magnesium compounds such as diethoxy magnesium and dibutoxy magnesium, organic magnesium compounds such as butyloctyl magnesium, inorganic acid magnesium salts and organic acid magnesium salts such as magnesium carbonate and magnesium stearate, and the like. Further, a compound having an average composition formula that is a mixed formula of the above magnesium compounds (for example, Mg(OEt) ｍ Cl ２－ｍ ; 0 < m < 2) may also be used. Among the above magnesium compounds, magnesium chloride, diethoxy magnesium, metallic magnesium, and butyl magnesium chloride are preferred. The above magnesium compounds may be used alone or in combination of two or more.

[0022] 1-1-3. As halogens contained in the halogen solid component, fluorine, chlorine, bromine, and iodine can be used. Among the above halogens, chlorine is preferred. The above halogens may be used individually or in combination of two or more. Generally, the halogen source for the solid component is a halogen-containing compound from the above titanium compounds and / or magnesium compounds. Other halogen-containing compounds may also be used as halogen sources. Examples of other halogen-containing compounds include silicon halide compounds such as silicon tetrachloride, aluminum halide compounds such as aluminum chloride, halogen-containing organic compounds such as 1,2-dichloroethane and benzyl chloride, borane halides such as trichloroborane, phosphorus halides such as phosphorus pentachloride, tungsten halides such as tungsten hexachloride, and molybdenum halides such as molybdenum pentachloride. Among the above other halogen-containing compounds, silicon tetrachloride is preferred. The halogen-containing compound may be used individually or in combination of two or more. The above titanium compounds and / or magnesium compounds containing halogens may be used in combination with other halogen-containing compounds.

[0023] 1-1-4. Electron Donor Any electron donor can be used as the electron donor contained in the solid component. Typical examples include the compounds disclosed in Japanese Patent Application Publication No. 2004-124090. Examples of electron donors include oxygen-containing electron donors such as organic acids and inorganic acids and their derivatives (esters, acid halides, amides, acid anhydrides), ether compounds, epoxy compounds, ketone compounds, aldehyde compounds, and alcohol compounds; nitrogen-containing electron donors such as ammonia compounds, amine compounds, nitrile compounds, and isocyanate compounds; and sulfur-containing electron donors such as sulfonic acid esters. The above electron donors may be used individually or in combination of two or more.

[0024] Examples of organic acids include aromatic carboxylic acids such as benzoic acid and phthalic acid; aliphatic carboxylic acids such as propionic acid, maleic acid, malonic acid, and malonic acid having one or two substituents at the 2-position, such as 2-n-butylmalonic acid; succinic acid and succinic acid having one or two substituents at the 2-position or one or more substituents at the 2-position and 3-position, such as 2-n-butylsuccinic acid; aromatic sulfonic acids such as benzenesulfonic acid; and aliphatic sulfonic acids such as methanesulfonic acid.

[0025] Examples of organic acid derivatives include organic acid esters, acid anhydrides, acid halides, and amides.

[0026] Examples of organic acid esters include esters of the organic acids listed above. As alcohols that are components of organic acid esters, aliphatic alcohols, aromatic alcohols, and alicyclic alcohols can be used. Examples of alcohols include alcohols consisting of aliphatic free radicals having 1 to 20 carbon atoms, such as ethyl, butyl, isobutyl, heptyl, octyl, and dodecyl groups, and alcohols consisting of alicyclic free radicals, such as cyclopentyl, cyclohexyl, and cycloheptyl groups. Among these alcohols, alcohols consisting of aliphatic free radicals having 1 to 20 carbon atoms, such as ethyl, butyl, isobutyl, heptyl, octyl, and dodecyl groups, are preferred. More preferably, alcohols consisting of aliphatic free radicals having 2 to 12 carbon atoms are preferred. Examples of organic acid esters include phthalate diesters such as diethyl phthalate, dibutyl phthalate, diisobutyl phthalate, and diheptyl phthalate; malonic acid esters having one or two substituents at the 2-position, such as 2-n-butyl-malonate diethyl; succinate esters having one or two substituents at the 2-position or one or more substituents at the 2-position and 3-position, such as 2-n-butyl-succinate diethyl and 2,3-diisopropylsuccinate diethyl.

[0027] Examples of acid anhydrides include acid anhydrides of the above-mentioned organic acids. Examples of organic acid halides include acid halides of the above-mentioned organic acids. Examples of halogens that are components of acid halides include fluorine, chlorine, bromine, iodine, etc. Among these halogens, chlorine is preferred. If the organic acid halide is a polyhalide of a polyhydric organic acid, the multiple halogens may be the same or different. Examples of organic acid halides include phthalic acid dihalides such as phthaloyl dichloride. Examples of organic acid amides include amides of the above-mentioned organic acids. Examples of amines that are components of amides include aliphatic amines such as ammonia, ethylamine, and dibutylamine, and aromatic amines such as aniline and benzylamine. Among these amines, ethylamine and dibutylamine are preferred. Examples of organic acid amides include acetamide, benzamide, and toluylamide. Among these organic acid amides, benzamide and toluylamide are preferred.

[0028] Examples of inorganic acids include carbonic acid, phosphoric acid, silicic acid, sulfuric acid, and nitric acid. Preferred inorganic acid derivatives include inorganic acid esters such as tetraethoxysilane (ethyl silicate), tetrabutoxysilane (butyl silicate), and tributyl phosphate.

[0029] Examples of ether compounds include aliphatic ethers such as dibutyl ether, aromatic ethers such as diphenyl ether, aliphatic polyvalent ethers such as 1,3-dimethoxypropane having one or two substituents at the 2 position, such as 2-isopropyl-2-isobutyl-1,3-dimethoxypropane and 2-isopropyl-2-isopentyl-1,3-dimethoxypropane, aromatic polyvalent ethers such as 9,9-bis(methoxymethyl)fluorene, and cyclic ethers such as furan, 2-methylfuran, 2-ethylfuran, 2,5-dimethylfuran, 2,5-diethylfuran, benzofuran, dibenzofuran, and tetrahydrofuran. Examples of epoxy compounds include ethylene oxide, propylene oxide, and glycidyl ethyl ether.

[0030] Examples of ketone compounds include aliphatic ketones such as methyl ethyl ketone, aromatic ketones such as acetophenone, and polyhydric ketones such as 2,2,4,6,6-pentamethyl-3,5-heptanedione. Examples of aldehyde compounds include aliphatic aldehydes such as propionaldehyde and aromatic aldehyde compounds such as benzaldehyde. Examples of alcohol compounds include aliphatic alcohols such as butanol and 2-ethylhexanol, aromatic alcohols such as phenol and cresol, aliphatic polyhydric alcohols such as glycerin, and aromatic polyhydric alcohols such as 1,1'-bi-2-naphthol.

[0031] Examples of amine compounds include aliphatic amines such as diethylamine, heterocyclic amines such as 2,2,6,6-tetramethylpiperidine, pyridine, and 2,6-lutidine, aromatic amines represented by aniline, and polyhydric amines represented by 1,3-bis(dimethylamino)-2,2-dimethylpropane.

[0032] Furthermore, compounds containing multiple electron-donating functional groups within the same molecule can also be used as electron donors. Examples of compounds containing multiple electron-donating functional groups within the same molecule include carboxylic acid esters having alkoxy groups in the molecule, such as 2-ethoxyethyl acetate and ethyl 3-ethoxy-2-t-butylpropionate, keto esters such as 2-benzoyl ethyl benzoate, keto ethers such as (1-t-butyl-2-methoxyethyl)methyl ketone, and amino ethers such as N,N-dimethyl-2,2-dimethyl-3-methoxypropylamine.

[0033] The electron donor is more preferably at least one of an organic acid ester compound, an acid halide compound, and an ether compound. Among the above electron donors, phthalate diesters such as diethyl phthalate, dibutyl phthalate, diisobutyl phthalate, and diheptyl phthalate; malonic acid diesters having one or two substituents at the 2 position, such as 2-n-butyl-malonate diethyl; succinic acid esters having one or two substituents at the 2 position or one or more substituents at the 2 and 3 positions, such as 2-n-butyl-succinate ethyl; phthalate dihalides such as phthaloyl dichloride; aliphatic polyvalent ethers such as 2-isopropyl-2-isobutyl-1,3-dimethoxypropane and 2-isopropyl-2-isopentyl-1,3-dimethoxypropane having one or two substituents at the 2 position; and polyvalent ethers having aromatic free radicals in the molecule, such as 9,9-bis(methoxymethyl)fluorene are preferred. More preferably, phthalate diesters and phthalate dihalides. The above electron donors may be used individually or in combination of two or more.

[0034] 1-1-5. Preparation of Solid Component (a1) The solid component can be obtained by contacting the above-mentioned titanium compound, magnesium compound, and electron donor components, or by contacting the above-mentioned titanium compound, magnesium compound, other halogen-containing compounds, and electron donor components. The ratio of the amounts of each component used is arbitrary as long as it does not significantly impair the effects of the present invention, but generally the following range is preferred. The amount of titanium compound used is preferably 0.0001 to 1,000 in molar ratio (moles of titanium compound / moles of magnesium compound) with respect to the amount of magnesium compound used, more preferably 0.001 to 100, and even more preferably 0.01 to 50.

[0035] When using compounds containing halogens other than magnesium compounds and titanium compounds, the amount used is preferably 0.01 to 1,000, and more preferably 0.1 to 100, in molar ratio (moles of the other halogen-containing compound / moles of the magnesium compound) relative to the amount of magnesium compound used, regardless of whether each of the magnesium compound and titanium compound contains halogens.

[0036] The amount of electron donor used is preferably 0.001 to 10, and more preferably 0.01 to 5, in molar ratio (moles of electron donor / moles of magnesium compound) relative to the amount of magnesium compound used, regardless of whether or not other halogen-containing compounds are used.

[0037] The contact conditions for each component are arbitrary as long as they do not significantly impair the effects of the present invention, but generally, the following conditions are preferred. The contact temperature is preferably -50°C to 200°C, and more preferably 0°C to 150°C. Examples of contact methods include dry contact using a rotary ball mill or a vibrating mill, and wet contact by stirring in the presence of an inert diluent.

[0038] During the preparation of the solid component (a1), washing with an inert solvent may be performed in the intermediate and / or final stage. Preferred solvents include aliphatic hydrocarbons such as heptane, aromatic hydrocarbons such as toluene and xylene, and halogen-containing hydrocarbons such as 1,2-dichloroethylene and chlorobenzene.

[0039] Any method can be used to prepare the solid component (a1) according to the present invention. For example, examples include conventionally known methods such as co-grinding, heat treatment, dissolution extraction, granulation, halogenation of magnesium (Mg) compounds, precipitation from organomagnesium compounds, impregnation, and composite methods combining these.

[0040] 1-1-6. Prepolymerization of Solid Component (a1) In the present invention, the solid component (a1) may be prepolymerized using a polymerization monomer in the presence of an organoaluminum compound as a co-catalyst. As the prepolymerization monomer in the prepolymerization, compounds disclosed in Japanese Patent Application Publication No. 2004-124090, etc., can be used. Specifically, the prepolymerization monomers include ethylene, propylene, 1-butene, 3-methylbutene-1, 1-pentene, 1-hexene, 4-methylpentene-1, 1-octene, 1-decene, 1-undecene, 1-eicosene, 1,3-butadiene, isoprene, 1,3-pentadiene, 1,4-pentadiene, 2,4-pentadiene, 1,4-hexadiene, 1,5-hexadiene, cis-2,trans-4-hexadiene, trans-2,trans-4-hexadiene, 1,3-heptadiene, 1,4-heptadiene, 1 Examples include 5-heptadiene, 1,6-heptadiene, 2,4-heptadiene, 2,6-octadiene, cyclopentadiene, dicyclopentadiene, 1,3-cyclohexadiene, 1,4-cyclohexadiene, 1,3-cycloheptadiene, 4-methyl-1,4-hexadiene, 5-methyl-1,4-hexadiene, 1,9-decadiene, 1,13-tetradecadiene, p-divinylbenzene, m-divinylbenzene, o-divinylbenzene, styrene, α-methylstyrene, allylbenzene, chlorostyrene, etc. The prepolymerization monomer may be derived from fossil fuels, biomass, chemical recycling, carbon recycling, or a mixture thereof.

[0041] The reaction conditions for prepolymerization are arbitrary as long as they do not significantly impair the effects of the present invention. Generally, the following ranges are preferred. The amount of prepolymerization is preferably 0.001 g to 100 g per gram of solid component (a1). More preferably 0.1 g to 50 g, and even more preferably 0.5 g to 10 g. The reaction temperature during prepolymerization is preferably -150°C to 150°C. More preferably 0°C to 100°C. Furthermore, the reaction temperature during prepolymerization is preferably lower than the polymerization temperature during the main polymerization. The reaction is generally preferably carried out under stirring, and an inert solvent such as hexane or heptane may be present. Prepolymerization may be carried out multiple times, and the polymerization monomers used may be the same or different. Furthermore, the solid component after prepolymerization can be washed with an inert solvent such as hexane or heptane. The type and amount of organoaluminum compound used can be the same as described later for component (a4).

[0042] 1-2. Silane compounds having an alkenyl group (a2) Component (a2) is a silane compound having an alkenyl group. Typical examples include the compounds disclosed in Japanese Patent Publication No. 2-34707, Japanese Patent Publication No. 2003-292522, Japanese Patent Publication No. 2006-169283, and Japanese Patent Publication No. 2011-74360.

[0043] As a silane compound having an alkenyl group, the compound represented by the following general formula (i) is preferred. General formula (i) SiR ａ ｎ R ｂ ４－ｎ (Here, R ａ Each of these independently represents an alkenyl group, R ｂ Each of these independently represents a hydrogen atom, a halogen atom, an alkyl group, or an alkoxy group, and n is 1, 2, 3, or 4, and when n is 1 or 2, R ｂ They may form a ring-shaped structure by being connected to each other.

[0044] In general formula (i), R ａEach of these independently represents an alkenyl group. Specific examples of alkenyl groups include vinyl, allyl, and 3-butenyl groups. Vinyl and allyl groups are preferred as alkenyl groups, with vinyl being more preferred. If the value of n is 2 or greater, there are multiple R ａ They may be the same or different. n may be 1, 2, or 3, or 1 or 2.

[0045] In general formula (i), R ｂ Each of these independently represents a hydrogen atom, a halogen atom, an alkyl group, or an alkoxy group. ｂ Examples of halogen atoms that can be used as such include fluorine, chlorine, bromine, and iodine atoms. ｂ The alkyl group may be a linear alkyl group, a branched alkyl group, or a cycloalkyl group. ｂ If R is an alkyl group, ｂ Generally, the alkyl group has 1 to 20 carbon atoms, preferably 1 to 12 carbon atoms. Specific examples of alkyl groups include methyl, ethyl, propyl, i-propyl, i-butyl, s-butyl, t-butyl, texyl, cyclopentyl, and cyclohexyl groups. ｂ If R is an alkoxy group, ｂ R is generally an alkoxy group having 1 to 20 carbon atoms, preferably 1 to 12 carbon atoms. Specific examples of alkoxy groups include methoxy, ethoxy, propoxy, i-propoxy, i-butoxy, s-butoxy, and t-butoxy groups. When the value of n is 1 or 2, there are multiple R ｂ They may be the same or different. When n is 1 or 2, R ｂ They may form a ring-shaped structure by being connected to each other. ｂ Examples of interconnected cyclic structures include the silacicopentane structure. ｂThe halogen atom is preferably an alkyl group, more preferably an alkyl group, even more preferably an alkyl group having 1 to 12 carbon atoms, even more preferably an alkyl group having 1 to 6 carbon atoms, and particularly preferably an alkyl group having 1 to 4 carbon atoms.

[0046] Examples of silane compounds having an alkenyl group (a2) include vinylsilane, methylvinylsilane, dimethylvinylsilane, trimethylvinylsilane, trichlorovinylsilane, dichloromethylvinylsilane, chlorodimethylvinylsilane, chloromethylvinylsilane, triethylvinylsilane, chlorodiethylvinylsilane, dichloroethylvinylsilane, dimethylethylvinylsilane, diethylmethylvinylsilane, tripentylvinylsilane, triphenylvinylsilane, diphenylmethylvinylsilane, dimethylphenylvinylsilane, CH ２ = CH - Si ( CH ３ ) ２ (C ６ H ４ CH ３ ), (CH ２ =CH)(CH ３ ) ２ Si-O-Si(CH ３ ) ２ (CH=CH ２), divinylsilane, dichlorodivinylsilane, dimethyldivinylsilane, diphenyldivinylsilane, allyltrimethylsilane, allyltriethylsilane, allyltrivinylsilane, allylmethyldivinylsilane, allyldimethylvinylsilane, allylmethyldichlorosilane, allyltrichlorosilane, allyltribromosilane, diallyldimethylsilane, diallyldiethylsilane, diallyldivinylsilane, diallylmethylvinylsilane, diallylmethylchlorosilane, diallyldichlorosilane, diallyldibromosilane, triallylmethylsilane, triallylethylsilane, triallylvinylsilane, triallylchlorosilane, triallylbromosilane, tetraallylsilane, di-3-butenyldimethylsilane, di-3-butenyldiethylsilane, Examples include di-3-butenyldivinylsilane, di-3-butenylmethylvinylsilane, di-3-butenylmethylchlorosilane, di-3-butenyldichlorosilane, tri-3-butenylethylsilane, tri-3-butenylvinylsilane, tri-3-butenylchlorosilane, tri-3-butenylbromosilane, tetra-3-butenylsilane, 1-methyl-1-vinylsilacyclobutane, 1-methyl-1-vinylsilacyclopentane, 1-methyl-1-vinylsilacyclohexane, 1,1-divinylsilacyclopentane, 1,1-divinylsilacyclohexane, 1-chloro-1-vinylsilacyclopentane, 1-chloro-1-vinylsilacyclohexane, 1-allyl-1-methylsilacyclopentane, and 1-allyl-1-methylsilacyclohexane.

[0047] Among the silane compounds having an alkenyl group described above, vinylsilane compounds are preferred, with trimethylvinylsilane, trichlorovinylsilane, dimethyldivinylsilane, and 1-methyl-1-vinylsilacyclopentane being more preferred. The silane compounds having an alkenyl group described above may be used individually or in combination of two or more.

[0048] The amount of silane compound (a2) having an alkenyl group used is arbitrary as long as it does not significantly impair the effects of the present invention, but generally, the following range is preferred. The amount of silane compound (a2) having an alkenyl group used is preferably 0.001 to 1,000, and more preferably 0.01 to 100, in terms of the molar ratio (number of moles of silane compound (a2) having an alkenyl group / number of moles of titanium atoms in the solid component (a1)) to the titanium constituting the solid component (a1).

[0049] The silane compound (a2) having an alkenyl group used in this invention typically exhibits greater steric hindrance than α-olefin monomers used in polymerization, and therefore does not polymerize with the Ziegler-Natta catalyst. However, due to the presence of a highly electron-donating organosilyl group, the charge density of the carbon-carbon double bond is very high, and it is thought that the silane compound (a2) having an alkenyl group coordinates to or inserts into the titanium atom, which is the active site. Therefore, it is expected to prevent over-reduction of the titanium atom by the organoaluminum compound (a4) described later, as well as deactivation of the active site due to impurities.

[0050] 1-3. Alkoxysilane Compound (a3) ​​Component (a3) ​​is an alkoxysilane compound. Alkoxysilane compound (a3) ​​is different from the silane compound (a2) having an alkenyl group described above. Examples of alkoxysilane compounds include compounds represented by the following general formula (ii). General formula (ii) R ｃ R ｄ ｍ Si ( OR ｅ ) ｎ (Here, R ｃ R represents a hydrocarbon group or a heteroatom-containing hydrocarbon group. ｄ Each of these independently represents a hydrogen atom, a halogen atom, a hydrocarbon group, or a heteroatom-containing hydrocarbon group. ｅ Each of these independently represents a hydrocarbon group, m is 0, 1, or 2, and n is 1, 2, or 3, satisfying the condition m + n = 3.

[0051] In general formula (ii), R ｃ R represents a hydrocarbon group or a heteroatom-containing hydrocarbon group. ｃIf it is a hydrocarbon group, it is a hydrocarbon group other than an alkenyl group. ｃ Generally, these are hydrocarbon groups having 1 to 20 carbon atoms, preferably 3 to 10 carbon atoms. Specific examples of hydrocarbon groups include linear aliphatic hydrocarbon groups such as n-propyl groups, branched aliphatic hydrocarbon groups such as i-propyl groups and t-butyl groups, alicyclic hydrocarbon groups such as cyclopentyl groups and cyclohexyl groups, and aromatic hydrocarbon groups such as phenyl groups. ｃ Branched aliphatic hydrocarbon groups or alicyclic hydrocarbon groups are preferred. More preferably, branched aliphatic hydrocarbon groups or alicyclic hydrocarbon groups having 3 to 6 carbon atoms are preferred, including i-propyl groups, i-butyl groups, t-butyl groups, texyl groups, cyclopentyl groups, and cyclohexyl groups. ｃ When is a heteroatom-containing hydrocarbon group, the heteroatom is preferably selected from a nitrogen atom, oxygen atom, sulfur atom, phosphorus atom, or silicon atom. More preferably, it is a nitrogen atom or an oxygen atom. ｃ The skeletal structure of the heteroatom-containing hydrocarbon group is R ｃ It is preferable to select from the examples where is a hydrocarbon group. More preferably, it is an N,N-diethylamino group, a quinolino group, or an isoquinolino group.

[0052] In general formula (ii), R ｄ Each of these independently represents a hydrogen atom, a halogen atom, a hydrocarbon group, or a heteroatom-containing hydrocarbon group. Examples of halogen atoms include fluorine, chlorine, bromine, and iodine atoms. ｄ If it is a hydrocarbon group, it is a hydrocarbon group other than an alkenyl group. ｄ Generally, these are hydrocarbon groups having 1 to 20 carbon atoms, preferably 1 to 10 carbon atoms. Specific examples of hydrocarbon groups include linear aliphatic hydrocarbon groups such as methyl and ethyl groups, branched aliphatic hydrocarbon groups such as i-propyl and t-butyl groups, alicyclic hydrocarbon groups such as cyclopentyl and cyclohexyl groups, and aromatic hydrocarbon groups such as phenyl groups. ｄMore preferably, it is a linear, branched aliphatic hydrocarbon group or alicyclic hydrocarbon group having 1 to 6 carbon atoms, and preferred members include methyl group, ethyl group, propyl group, i-propyl group, i-butyl group, s-butyl group, t-butyl group, texyl group, cyclopentyl group, cyclohexyl group, and the like. ｄ If R is a heteroatom-containing hydrocarbon group, ｃ It is preferable to select from the examples of cases where is a heteroatom-containing hydrocarbon group. More preferably, it is an N,N-diethylamino group, a quinolino group, or an isoquinolino group. Also, regardless of the value of m, R ｄ R ｃ It may be the same as or different from. m is 0, 1, or 2, but may be 0 or 1, or it may be 1.

[0053] In general formula (ii), R ｅ Each of these independently represents a hydrocarbon group. ｅ This generally refers to a hydrocarbon group having 1 to 20 carbon atoms, preferably 1 to 10 carbon atoms, and more preferably 1 to 5 carbon atoms. Specific examples of hydrocarbon groups include linear aliphatic hydrocarbon groups such as methyl and ethyl groups, and branched aliphatic hydrocarbon groups such as i-propyl and t-butyl groups. ｅ As such, methyl groups and ethyl groups are preferred. When the value of n is 2 or more, there are multiple R ｅ They may be the same or different. n is 1, 2, or 3, and satisfies m + n = 3, but n may be 2 or 3, or it may be 2.

[0054] Examples of alkoxysilane compounds (a3) ​​include t-butylmethyldimethoxysilane, t-butylmethyldiethoxysilane, t-butylethyldimethoxysilane, t-butyl-n-propyldimethoxysilane, cyclohexylmethyldimethoxysilane, cyclohexylethyldimethoxysilane, dicyclopentyldimethoxysilane, diisopropyldimethoxysilane, diisobutyldimethoxysilane, isobutylisopropyldimethoxysilane, n-propylmethyldimethoxysilane, t-butyltriethoxysilane, bis(diethylamino)dimethoxysilane, diethylaminotriethoxysilanemethoxysilane, and bisperhydroisoquinolinodimethoxysilane. The above alkoxysilane compounds may be used individually or in combination of two or more.

[0055] The amount of alkoxysilane compound (a3) ​​used is arbitrary as long as it does not significantly impair the effects of the present invention, but generally, the following range is preferred. The amount of alkoxysilane compound (a3) ​​used is preferably 0.01 to 1,000, and more preferably 0.1 to 100, in terms of the molar ratio (number of moles of alkoxysilane compound (a3) ​​ / number of moles of titanium atoms in solid component (a1)) to the titanium constituting the solid component (a1).

[0056] The alkoxysilane compound (a3) ​​used in this invention is thought to coordinate near titanium atoms that can act as active sites, thereby controlling catalytic performance such as the catalytic activity of the active sites and the regularity of the polymer.

[0057] 1-4. Organoaluminum Compound (a4) As the organoaluminum compound (a4) used in the present invention, compounds disclosed in Japanese Patent Application Publication No. 2004-124090 can be used. Generally, it is desirable to use a compound represented by the following general formula (iii). Formula (iii) R ｆ ｐ AlX ｑ (OR ｇ ) ｒ (In general formula (iii), R ｆ R represents a hydrocarbon group with 1 to 10 carbon atoms. X represents a halogen atom or a hydrogen atom. ｇrepresents a hydrocarbon group or a bridged group made of Al. p is a real number between 1 and 3, q ​​is a real number between 0 and 2, r is a real number between 0 and 2, and p + q + r = 3.

[0058] R ｆ R is a hydrocarbon group having 1 to 10 carbon atoms, preferably 1 to 8 carbon atoms, more preferably 1 to 6 carbon atoms. ｆ Specific examples include methyl group, ethyl group, n-propyl group, n-butyl group, isobutyl group, n-hexyl group, n-octyl group, etc. Of these, methyl group, ethyl group, and isobutyl group are most preferred. X is a halogen atom or a hydrogen atom. Examples of halogen atoms that can be used as X include fluorine atom, chlorine atom, bromine atom, iodine atom, etc. Of these, chlorine is particularly preferred. R ｇ R is a bridging group consisting of a hydrocarbon group or an aluminum atom (Al). ｇ If R is a hydrocarbon group, ｆ From the same group as the examples of hydrocarbon groups, R ｇ You can choose this. Furthermore, as the organoaluminum compound (a4), it is also possible to use almoxane compounds, such as methylalmoxane, in which case R ｇ This represents a crosslinking group formed by Al.

[0059] Examples of compounds that can be used as organoaluminum compounds (a4) include trimethylaluminum, triethylaluminum, triisobutylaluminum, tri-n-octylaluminum, diethylaluminum chloride, ethylaluminum chloride, diethylaluminum ethoxide, and methylaluminoxane. Among these, triethylaluminum and triisobutylaluminum are preferred as organoaluminum compounds (a4). Organoaluminum compounds (a4) can be used individually or in combination of multiple compounds.

[0060] The amount ratio of the organoaluminum compound (a4) used can be any amount as long as it does not impair the effects of the present invention, but generally, it is preferable to be within the following range. The amount of organoaluminum compound (a4) used is preferably in the range of 0.1 to 100, and particularly preferably in the range of 1 to 50, in terms of the molar ratio (number of moles of aluminum atoms / number of moles of titanium atoms in the solid component (a1)) to the titanium component constituting the solid component (a1).

[0061] The organoaluminum compound (a4) used in this invention is primarily used to efficiently support the alkoxysilane compound (a2) in the solid catalyst component (A). Therefore, it is distinct from and differs in primary purpose from organoaluminum compounds used as co-catalysts in polymerization reactions during prepolymerization or main polymerization. Note that organoaluminum (a4) is included in the solid catalyst component (A) in a state after reacting with the halogen and electron donor.

[0062] (Method for preparing solid catalyst components) The solid catalyst components used in the present invention are obtained by contacting the above-mentioned components that constitute the solid catalyst components to form a solid component. The contact treatment may be performed multiple times. The contact conditions for each component must be such that oxygen is not present, but any conditions can be used as long as they do not impair the effects of the present invention. Generally, the following conditions are preferred. The contact temperature is about -50°C to 200°C, preferably 0°C to 150°C. Examples of contact methods include mechanical methods such as rotary ball mills and vibratory mills, and methods of contact by stirring in the presence of an inert diluent.

[0063] When preparing the solid catalyst components, washing with an inert solvent may be performed as an intermediate and / or final step. Examples of preferred inert solvents include aliphatic hydrocarbon compounds such as heptane, aromatic hydrocarbon compounds such as toluene and xylene, and halogen-containing hydrocarbon compounds such as 1,2-dichloroethylene and chlorobenzene.

[0064] The contact temperature may be between 0°C and 110°C, and is preferably between 20°C and 100°C. Methods of contact include dry contact using a rotary ball mill or vibratory mill, and wet contact by stirring in the presence of an inert diluent. Wet contact by stirring in the presence of an inert diluent is preferred.

[0065] In the contact treatment, the contact procedure between the solid component (a1), the silane compound having an alkenyl group (a2), the alkoxysilane compound (a3), and the organoaluminum compound (a4) is arbitrary, but specific examples include the following procedures (i) to (iv), with procedure (i) or procedure (ii) being preferred. Procedure (i): A method of contacting the solid component (a1) with the silane compound having an alkenyl group (a2), then with the alkoxysilane compound (a3), and then with the organoaluminum compound (a4). Procedure (ii): A method of contacting the solid component (a1) with a silane compound having an alkenyl group (a2) and an alkoxysilane compound (a3) ​​that have been contacted beforehand, and then with the organoaluminum compound (a4). Procedure (iii): A method of contacting the solid component (a1) with the alkoxysilane compound (a3), then with the silane compound having an alkenyl group (a2), and then with the organoaluminum compound (a4). Procedure (iv): A method of contacting a solid component (a1) with a silane compound (a2) having an alkenyl group, an alkoxysilane compound (a3), and an organoaluminum compound (a4) that have been previously in contact with each other.

[0066] (Metallocene-based catalysts) Examples of olefin polymerization catalyst components (A) that serve as metallocene-based catalysts include a solid catalyst component in which (a) a metallocene complex and (b) a compound that reacts with the metallocene complex to form an ion pair are supported on a particulate carrier, or a solid catalyst component in which (a) the metallocene complex is supported on an ion-exchangeable layered silicate.

[0067] Examples of metallocene complexes in metallocene catalysts include compounds represented by the following general formulas (1) to (4).

[0068] [In the above general formulas (1) to (4), A and A' represent conjugated five-membered ring ligands which may have substituents (A and A' may be the same or different within the same compound), Q represents a bonding group that bridges two conjugated five-membered ring ligands at any position, Z represents a ligand containing a nitrogen atom, oxygen atom, silicon atom, phosphorus atom or sulfur atom, hydrogen atom, halogen atom or hydrocarbon group, Z' represents a ligand containing a nitrogen atom, oxygen atom, silicon atom, phosphorus atom or sulfur atom or hydrocarbon group. Q' represents a bonding group that bridges any position of a conjugated five-membered ring ligand with any position of Z', M represents a metal atom selected from Group 4 of the periodic table, and X and Y represent a hydrogen atom, halogen atom, hydrocarbon group, alkoxy group, amino group, phosphorus atom-containing hydrocarbon group or silicon atom-containing hydrocarbon group (X and Y may be the same or different within the same compound).]

[0069] Examples of conjugated five-membered ring ligands for A and A' include those derived from cyclopentadiene, indene, tetrahydroindene, fluorene, azulene, and tetrahydroazulene. These may be unsubstituted or substituted. Among these, substituted or unsubstituted indenyl or azulenyl groups are particularly preferred.

[0070] Examples of substituents on the conjugated five-membered ring ligand include hydrocarbon groups having 1 to 40 carbon atoms, preferably 1 to 30 carbon atoms; hydrocarbon groups having 1 to 30 carbon atoms substituted with halogen atoms such as fluorine, chlorine, or bromine; halogen atoms such as fluorine, chlorine, or bromine; alkoxy groups having 1 to 12 carbon atoms, such as silicon-containing hydrocarbon groups represented by -Si(R)(R')(R''); phosphorus-containing hydrocarbon groups represented by -P(R)(R'); or boron-containing hydrocarbon groups represented by -B(R)(R'). If there are multiple substituents, each substituent may be the same or different. The above-mentioned R, R', and R'' may be the same or different and represent alkyl groups having 1 to 24 carbon atoms, preferably 1 to 18 carbon atoms. Furthermore, substituents on the conjugated five-membered ring ligand may have at least one element from groups 15 and 16 of the periodic table (i.e., a heteroatom). Preferred substituents include monocyclic or polycyclic substituents containing at least one heteroatom selected from the group consisting of oxygen, sulfur, nitrogen, and phosphorus atoms in a five-membered or six-membered ring. More preferably, substituents are derived from optionally substituted heteroaromatic compounds, with particularly preferred substituents being optionally substituted furyl groups and optionally substituted thienyl groups. In the case of compounds having a bridging group represented by general formula (2) or (4), these substituents are not particularly limited, but are preferably located at the α-position (relative to the bonding site with the bridging group) on the conjugated five-membered ring ligand.

[0071] Q represents a bonding group that crosslinks between two conjugated five-membered ring ligands at an arbitrary position, and Q' represents a bonding group that crosslinks an arbitrary position of a conjugated five-membered ring ligand and an arbitrary position of Z'. Specific examples of Q and Q' include the following groups. (a) Alkylene groups such as methylene group, ethylene group, isopropylene group, dimethylmethylene group, phenylmethylmethylene group, diphenylmethylene group, cyclobutylene group, cyclohexylene group, etc. (b) Silylene groups such as dimethylsilylene group, diethylsilylene group, dipropylsilylene group, diphenylsilylene group, methylethylsilylene group, methylphenylsilylene group, methyl-t-butylsilylene group, disilylene group, tetramethyldisilylene group, silacyclobutylene group, etc. (c) Substituted germylene group, substituted phosphorus group, substituted amino group, substituted boron group or substituted alminylene group substituted with a hydrocarbon group

[0072] Further specifically, (CH ３ ), ２ Ge, (C ６ H ５ ), ２ Ge, (CH ３ ),P, (C ６ H ５ ), ４ H ９ ),N, (C ６ H ５ ), ４ H ９ ),B, (C ６ H ５ ), ６ H ５ ),Al, (C ６ H ５ O)Al and other groups. Preferred are alkylene groups or silylene groups.

[0073] Furthermore, M represents a metal atom, and in particular, a transition metal atom selected from Group 4 of the periodic table. Examples of M include titanium, zirconium, and hafnium. Zirconium and hafnium are particularly preferred. In addition, Z represents a ligand containing a nitrogen atom, oxygen atom, silicon atom, phosphorus atom, or sulfur atom, a hydrogen atom, a halogen atom, or a hydrocarbon group, and Z' represents a ligand containing a nitrogen atom, oxygen atom, silicon atom, phosphorus atom, or sulfur atom, or a hydrocarbon group. Preferred specific examples of Z and Z' include an oxygen atom-containing hydrocarbon group having 1 to 40 carbon atoms, preferably 1 to 18 carbon atoms; a sulfur atom-containing hydrocarbon group having 1 to 40 carbon atoms, preferably 1 to 18 carbon atoms; a silicon atom-containing hydrocarbon group having 1 to 40 carbon atoms, preferably 1 to 18 carbon atoms; a nitrogen atom-containing hydrocarbon group having 1 to 40 carbon atoms, preferably 1 to 18 carbon atoms; a phosphorus atom-containing hydrocarbon group having 1 to 40 carbon atoms, preferably 1 to 18 carbon atoms; and a hydrocarbon group having 1 to 20 carbon atoms. Further preferred specific examples of Z include a hydrogen atom, a chlorine atom, and a bromine atom.

[0074] X and Y are, respectively, a hydrogen atom, a halogen atom, a hydrocarbon group having 1 to 20 carbon atoms, preferably 1 to 10 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, preferably 1 to 10 carbon atoms, an amino group, a phosphorus atom-containing hydrocarbon group having 1 to 20 carbon atoms, preferably 1 to 12 carbon atoms, such as a diphenylphosphono group, or a silicon atom-containing hydrocarbon group having 1 to 20 carbon atoms, preferably 1 to 12 carbon atoms, such as a trimethylsilyl group or a bis(trimethylsilyl)methyl group. X and Y may be the same or different. Of these, halogen atoms, hydrocarbon groups having 1 to 10 carbon atoms, and amino groups having 1 to 12 carbon atoms are particularly preferred.

[0075] Specific examples of compounds represented by the general formulas (1) to (4) include, but are not limited to, those described in paragraphs 0098 to 0106 of International Publication No. 2022 / 059764.

[0076] Furthermore, (a) as the metallocene complex, a metallocene complex represented by the following general formula [I] can also be suitably used.

[0077] (In formula [I], M is Ti, Zr, or Hf, Q is a carbon atom, a silicon atom, or a germanium atom, and X １ and X ２ Each of these is independently a halogen atom, a C1-C6 alkyl group, a C6-C18 aryl group, an amino group substituted with a C1-C6 alkyl group, a C1-C6 alkoxy group, a C1-C6 halogen-containing alkyl group, or a C6-C18 halogen-containing aryl group. １ and R １１ These may be the same or different from each other, and are a hydrogen atom, a C1-C6 alkyl group, a C1-C6 alkoxy group, a furyl group, a thienyl group, a substituted furyl group, or a substituted thienyl group, R １ and R １１ One or both of these are always a furyl group, a thienyl group, a substituted furyl group, or a substituted thienyl group. ７ and R １７ These may be the same or different from each other, and are a hydrogen atom, a halogen atom, a C1-C6 alkyl group, a C1-C6 alkoxy group, a C1-C6 halogen-containing alkyl group, a C1-C6 alkyl group having a trialkylsilyl group, a C1-C6 silyl group having a hydrocarbon group, a C6-C18 aryl group, or a C6-C18 halogen-containing aryl group, R ７ and R １７ If either of them is a hydrogen atom, the other is a substituent other than a hydrogen atom. ８ and R １８ These may be the same or different from each other, and are a hydrogen atom, a halogen atom, a C1-C6 alkyl group, a C1-C6 alkoxy group, a C1-C6 halogen-containing alkyl group, a C1-C6 alkyl group having a trialkylsilyl group, a C1-C6 silyl group having a hydrocarbon group, a C6-C18 aryl group, or a C6-C18 halogen-containing aryl group. Also, R ７ , R ８ , R １７ and R １８ The substituents may form a 5-7 membered ring on both adjacent sides, and the 5-7 membered ring may contain an unsaturated bond. ２ , R３ , R ４ , R ５ , R ６ , R ９ , R １２ , R １３ , R １４ , R １５ , R １６ and R １９ These may be the same or different from each other, and are a hydrogen atom, a halogen atom, a C1-C6 alkyl group, a C1-C6 alkoxy group, a C1-C6 halogen-containing alkyl group, a C1-C6 alkyl group having a trialkylsilyl group, a C6-C18 aryl group, a C6-C18 halogen-containing aryl group, a furyl group, a thienyl group, a substituted furyl group, or a substituted thienyl group. Also, R ２ , R ３ , R ４ , R ５ , R ６ , R １２ , R １３ , R １４ , R １５ and R １６ A may form a 5-7 membered ring with both adjacent substituents, and this 5-7 membered ring may contain an unsaturated bond. A is a divalent hydrocarbon group having 3 to 12 carbon atoms that forms a ring with Q to which it is bonded, and may contain an unsaturated bond. R １０ m is a substituent of A, which is a C1-C6 alkyl group, a C1-C6 halogen-containing alkyl group, a C1-C6 alkyl group having a trialkylsilyl group, a C1-C6 silyl group having a hydrocarbon group, a C6-C18 aryl group, or a C6-C18 halogen-containing aryl group. m is an integer from 0 to 24. If m is 2 or greater, R １０ They may also be linked together to form a new ring structure.

[0078] The explanation of each symbol of the metallocene complex represented by the general formula [I] is incorporated into this specification from paragraphs 0031 to 0055 of Japanese Patent Application Publication No. 2015-193605. Specific examples of the metallocene complex represented by the general formula [I] are those described in paragraphs 0056 to 0063 of Japanese Patent Application Publication No. 2015-193605.

[0079] In the metallocene catalyst, (a) the metallocene complex can be used alone or in combination of two or more types.

[0080] In a metallocene catalyst, when (a) a metallocene complex and (b) a compound that reacts with the metallocene complex to form an ion pair are supported on a particulate carrier, examples of compounds that form ion pairs include aluminum oxy compounds and boron compounds. Examples of particulate carriers include inorganic carriers made of inorganic materials, such as SiO ２ Al ２ O ３ MgO, ZrO ２ , TiO ２ , B ２ O ３ , CaO, ZnO, BaO, ThO ２ , and inorganic metal oxide supports such as mixtures containing two or more of these, MgCl ２ MgBr ２ , MnCl ２ MnBr ２ Examples of inorganic chloride supports include the above. Among these, from the viewpoint of production efficiency per gram of catalyst, (a) a solid catalyst component in which a metallocene complex is supported on an ion-exchangeable layered silicate is preferred. These components (b) and the ion-exchangeable layered silicate may be used individually or as a mixture of two or more. The compound or ion-exchangeable layered silicate that reacts with the metallocene complex to form an ion pair may be the same as described in paragraphs 0071 to 0086 of Japanese Patent Application Publication No. 2015-193605.

[0081] (Prepolymerization of Solid Catalyst Components) The solid catalyst component may be prepolymerized using a polymerization monomer in the presence of an organoaluminum compound as a co-catalyst. Examples of prepolymerization monomers in prepolymerization are the same as those mentioned above.

[0082] The reaction conditions for prepolymerization are arbitrary as long as they do not significantly impair the effects of the present invention. Generally, the following ranges are preferred. The amount of prepolymerization is preferably 0.001 g to 100 g per gram of solid catalyst component. More preferably 0.1 g to 50 g, and even more preferably 0.5 g to 10 g. The reaction temperature during prepolymerization is preferably -150°C to 150°C. More preferably 0°C to 100°C. Furthermore, the reaction temperature during prepolymerization is preferably lower than the polymerization temperature during the main polymerization. The reaction is generally preferably carried out under stirring, and an inert solvent such as hexane or heptane may be present. Prepolymerization may be carried out multiple times, and the polymerization monomers used may be the same or different. Furthermore, the solid catalyst component after prepolymerization can be washed with an inert solvent such as hexane or heptane. The type and amount of organoaluminum compound used can be the same as described above for component (a4).

[0083] The solid catalyst component obtained by prepolymerization contains a polymer of a compound having an ethylenic double bond (prepolymerized polymer). When propylene is homopolymerized or copolymerized using this solid catalyst component, the prepolymerized polymer functions as a shell, thereby suppressing the generation of fine particles due to cracking of catalyst particles during the main polymerization.

[0084] 2. Component (B): Organoaluminum Compound There are no particular restrictions on the organoaluminum compound (B) used in the method for producing the propylene-based block copolymer of the present invention, and various known compounds can be used. Examples of these compounds include trialkylaluminum, halogen-containing organoaluminum compounds, hydride-containing organoaluminum compounds, alkoxide-containing organoaluminum compounds, aluminoxanes, and other known compounds. In the case of a Ziegler-Natta catalyst, the organoaluminum compound (B) can be selected from the same group as the examples of organoaluminum compounds (a4) listed as components when preparing the solid catalyst component. The organoaluminum compound (B) may be the same as or different from the organoaluminum compound (a4) used when preparing the solid catalyst component. The organoaluminum compound (B) may be a single compound or two or more compounds may be used in combination. In the case of a metallocene catalyst, the organoaluminum compound (B) can be selected from the same group as the examples of organoaluminum compounds (a4) listed as components when preparing the solid catalyst component of a Ziegler-Natta catalyst. The organoaluminum compound (B) may be the same as or different from the organoaluminum compound used in prepolymerization, and one compound may be used, or two or more compounds may be used in combination. In the case of a Ziegler-Natta type catalyst, the amount of organoaluminum compound (B) used is preferably in the range of 1 to 5,000, and particularly preferably in the range of 10 to 500, in terms of the molar ratio (moles of organoaluminum compound / moles of titanium atoms in the solid catalyst component) to the titanium component constituting the solid catalyst component. In the case of a metallocene type catalyst, the amount of organoaluminum compound (B) used is preferably in the range of 1 to 2,000, and particularly preferably in the range of 10 to 700, in terms of the molar ratio (moles of organoaluminum compound / moles of metal atoms in the solid catalyst component) to the metal atoms constituting the solid catalyst component.

[0085] II. Method for Propylene Block Copolymer 1. First Polymerization Step In the production method of the present invention, in the first polymerization step, one or more reactors are used to produce at least one first propylene polymer selected from a propylene homopolymer and a copolymer of propylene and at least one monomer selected from the group consisting of propylene and α-olefins other than propylene (provided that the propylene content of the first propylene polymer exceeds 95% by mass) in the presence of a catalyst containing an olefin polymerization catalyst component (A) and an organoaluminum compound (B).

[0086] Examples of at least one monomer selected from the group consisting of α-olefins other than propylene include α-olefins such as ethylene, 1-butene, 1-pentene, 4-methylpentene-1, 1-hexene, 1-octene, 1-nonene, and 1-decene, and may be at least one selected from the group consisting of ethylene and linear or branched α-olefins having 4 to 8 carbon atoms, with ethylene or 1-butene being preferred.

[0087] The first propylene polymer is at least one selected from propylene homopolymers and copolymers of propylene and at least one monomer selected from the group consisting of propylene and α-olefins other than propylene (hereinafter sometimes referred to as comonomers), and has a propylene content of more than 95% by mass. The first propylene polymer is a polymer with a propylene basic skeleton having a propylene content of more than 95% by mass, and may be a crystalline propylene polymer. In the present invention, the crystalline propylene polymer means one that has stereoregularity and can form lamellae.

[0088] In the first propylene polymer, the propylene content is greater than 95% by mass, but may be 97% by mass or more, 99% by mass or more, or 99.7% by mass or more. That is, in the first propylene polymer, the comonomer content is in the range of 0% by mass to less than 5% by mass, may be in the range of 0% by mass to 3% by mass, may be in the range of 0% by mass to 1% by mass, and may be in the range of 0% by mass to 0.3% by mass.

[0089] Various known apparatuses can be used as the polymerization method for producing the propylene-based block copolymer of the present invention. Preferably, the polymerization method of the production method of the present invention employs a gas-phase polymerization method that substantially avoids the use of liquid solvents and keeps each monomer in a gaseous state, so that the catalyst and monomers come into efficient contact and the production efficiency per gram of catalyst is good. The first polymerization step may be a gas-phase polymerization step. Continuous and batch polymerization methods are applicable.

[0090] The number of polymerization reactors may be one or more. If there are multiple polymerization reactors, they may be connected in series or in parallel. Examples of gas-phase polymerization reactors include fluidized bed reactors and horizontal reactors having a stirrer that rotates around a horizontal axis. Horizontal reactors have a significantly different characteristic from other reactor types in that the catalyst component is supplied to the upstream part of the reactor, and as it grows into polymer particles through polymerization, it moves to the downstream side of the reactor. Horizontal reactors with such characteristics have a larger effective number of stages per polymer reactor compared to fully mixed-tank type polymer reactors, exhibiting behavior closer to that of a multi-stage reactor, and in particular, the concentration of polymer particles with relatively short residence times (short-pass polymer particles) located near the reactor outlet tends to be lower. Therefore, in the present invention, which aims to reduce gel and fish-eye formation, polymerization is preferably carried out in a horizontal reactor.

[0091] In these reactors, the catalyst and monomer are typically supplied continuously, and the polymerized polymer is withdrawn from the reactor steadily or intermittently. Alternatively, the monomer gas in the reactor is liquefied using an external compressor or condenser, and this liquefied monomer is sprayed into the reactor to remove the polymerization heat (reaction heat) by its latent heat of vaporization. In the present invention, polymerization is preferably carried out using a gas-phase polymerization method in which the reaction heat is removed mainly by the heat of vaporization of liquefied propylene. If the first polymerization step is a gas-phase polymerization step, it is preferable that the reaction heat is removed mainly by the heat of vaporization of liquefied propylene.

[0092] Polymerization conditions such as temperature and pressure can be set arbitrarily as long as they do not hinder the effects of the present invention. Specifically, the polymerization temperature is preferably 0°C or higher, more preferably 30°C or higher, particularly preferably 40°C or higher, preferably 100°C or lower, more preferably 90°C or lower, and particularly preferably 80°C or lower. The polymerization pressure is atmospheric pressure or higher, preferably 600 kPa or higher, more preferably 1000 kPa or higher, particularly preferably 1600 kPa or higher, preferably 4200 kPa or lower, more preferably 3500 kPa or lower, and particularly preferably 3000 kPa or lower. However, the polymerization pressure should not be set lower than the vapor pressure of propylene at the polymerization temperature.

[0093] The average residence time can be arbitrarily adjusted according to the polymerizer configuration and product index. Generally, it is set within the range of 30 minutes to 10 hours. A preferred average residence time is within 4 hours, and more preferably within 3 hours. Generally, selecting a longer average residence time can increase the production efficiency per gram of catalyst, but if the average residence time is excessive, the rate of increase in production efficiency per gram of catalyst with respect to the increase in average residence time decreases. Also, when producing the same amount of polymer, the time increases and productivity decreases. Therefore, the above average residence time range may be used, taking into consideration the balance between productivity and production efficiency per gram of catalyst. In the method for producing propylene-based block copolymers of the present invention, it is preferable in the first polymerization step to produce the first propylene-based polymer with 40,000 g or more per gram of the olefin polymerization catalyst, from the viewpoint of balancing productivity and production efficiency per gram of catalyst, and it is more preferable to produce the first propylene-based polymer with 50,000 g or more, and even more preferably 55,000 g or more, per gram of the olefin polymerization catalyst.

[0094] 2. Second Polymerization Step In the manufacturing method of the present invention, the second polymerization step includes a step of polymerizing a copolymer of a propylene content of 95% by mass or less and at least one monomer selected from the group consisting of α-olefins other than propylene, in the presence of the first propylene polymer, using one or more reactors including a horizontal reactor, to produce a second propylene polymer. The second polymerization step includes supplying an electron-donating compound, which is liquid at standard conditions, to the final horizontal reactor at any point between the furthest downstream end in the longitudinal direction of the final horizontal reactor and 66% upstream, and adjusting the oxygen concentration in the reactor to less than 0.60 mol ppm. Standard conditions refer to 0°C (273.15 K) and 1 atm (101.325 kPa).

[0095] The second polymerization step first includes a step in which, in a reactor to which the first propylene-based polymer produced in the first polymerization step has been transferred, a copolymer is polymerized in the presence of the first propylene-based polymer with at least one monomer selected from the group consisting of 95% by mass or less of propylene and α-olefins other than propylene.

[0096] In the second polymerization step, the at least one monomer (comonomer) selected from the group consisting of α-olefins excluding propylene may be the same as in the first polymerization step. In particular, the comonomer may be ethylene or 1-butene, or it may be ethylene.

[0097] In the second propylene polymer, the propylene content may be 95.0% by mass or less, 90.0% by mass or less, 80.0% by mass or less, 70.0% by mass or less, while on the other hand, it may be 10.0% by mass or more, 20.0% by mass or more, 30.0% by mass or more, 40.0% by mass or more, or 56.0% by mass or more. That is, in the second propylene polymer, the comonomer content may be 5.0% by mass or more, 10.0% by mass or more, 20.0% by mass or more, or 30.0% by mass or more, while on the other hand, it may be 90.0% by mass or less, 80.0% by mass or less, 70.0% by mass or less, 60.0% by mass or less, or 44.0% by mass or less.

[0098] The ratio of the amount of polymerization in the second polymerization step to the total amount of polymerization, that is, the ratio of the second propylene polymer in the propylene block copolymer, can be appropriately selected according to the desired properties of the propylene block copolymer, and may be 10.0% by mass or more, 12.0% by mass or more, 15.0% by mass or more, on the other hand, it may be 30.0% by mass or less, 28.0% by mass or less, 25.0% by mass or less, or 22.0% by mass or less. If the ratio of the second propylene polymer in the propylene block copolymer is too small, the impact strength of the propylene block copolymer will decrease, and if it is too large, the fluidity of the propylene block copolymer will deteriorate significantly, which may cause problems with extraction from the polymerizer, adhesion inside the polymerizer, or increased gel formation. The ratio of the amount of polymerization in the second polymerization step to the total amount of polymerization, i.e., the ratio of the second propylene polymer in the propylene block copolymer, can be controlled by adjusting the polymerization time (average residence time) in the second polymerization step, the polymerization pressure and polymerization temperature in the second polymerization step, and the amount of polymerization activity inhibitor added to control the amount of polymerization in the second polymerization step. The polymerization conditions in the second polymerization step, such as the polymerization temperature and polymerization pressure, may be the same as those described for the first polymerization step and can be selected and used as appropriate. Increasing the polymerization time, increasing the polymerization pressure and polymerization temperature, and decreasing the amount of polymerization activity inhibitor added will increase the amount of polymerization in the second polymerization step.

[0099] The second polymerization step is preferably a gas-phase polymerization step. Continuous and batch polymerization methods are applicable. When the second polymerization step is a gas-phase polymerization step, it is preferable that the reaction heat is removed mainly by the heat of vaporization of liquefied propylene. In the second polymerization step, one or more reactors, including a horizontal reactor, are used to produce the second propylene-based polymer. In the second polymerization step, one horizontal reactor may be used, or two or more reactors including horizontal reactors may be used. If there are multiple reactors, they may be connected in series or in parallel.

[0100] In the second polymerization step, one or more reactors, including a horizontal reactor, are used. Of the horizontal reactors used, the electron-donating compound, which is liquid at standard conditions, is supplied to the final horizontal reactor at any point within 66% of the length from the furthest downstream end of the final horizontal reactor to the upstream end. If there is one reactor in the second polymerization step, one horizontal reactor is used, and the electron-donating compound, which is liquid at standard conditions, is supplied to this horizontal reactor. If there are two or more reactors in the second polymerization step, the electron-donating compound, which is liquid at standard conditions, is supplied to the final horizontal reactor.

[0101] Here, the horizontal reactor will be described in detail using Figure 2. The horizontal reactor 200 is long and narrow and has partition walls 210a and 210b, and is generally installed in a horizontal position as shown in Figure 2. The polymerization reaction takes place in the space between partition walls 210a and 210b inside the horizontal reactor 200. In Figure 2, the partition wall 210a on the upstream side where the transfer pipe 201 is located is the upstream end of the reactor, and the partition wall 210b is the downstream end of the reactor. The horizontal reactor may be a horizontal reactor having a stirrer that rotates around a horizontal axis inside. In the horizontal reactor in Figure 2, the horizontal axis 209a of the stirrer 209 extends from the upstream to the downstream end of the horizontal reactor 200, and multiple stirring blades 209b for stirring are installed inside the horizontal reactor 200. The stirring blades 209b mix the polymer particles with other substances introduced into the horizontal reactor 200. In the horizontal reactor 200, the first propylene-based polymer introduced from the transfer pipe 201, or polymer particles polymerized in the preceding reactor containing the first propylene-based polymer, are mixed with monomers by the stirring blades and polymerization begins. During polymerization, the heat of polymerization generated is removed by the latent heat of vaporization of the raw material liquefied propylene supplied from the liquefied monomer-containing liquid supply pipes 207-1 to 207-5. Unreacted propylene gas is removed from the reaction system via the unreacted gas extraction pipe 210, a portion of which is condensed in the condenser 205, and separated into liquid and gas phases in the gas-liquid separation tank 211. The liquid phase is introduced into the liquefied monomer-containing liquid supply pipes 207-1 to 207-5 to remove the heat of polymerization, and the gas phase is mixed with hydrogen, α-olefins, etc., for molecular weight adjustment, pressurized by the compressor 212, and supplied via the recycled gas supply pipes 208-1 to 208-5 installed at the bottom of the reactor 200. At this time, the flow rate of the liquefied monomer-containing liquid from the liquefied monomer-containing liquid supply pipes 207-1 to 207-5, which are arranged at specific intervals at the top, and the temperature-controlled mixed gas flow rate from the recycle gas supply pipes 208-1 to 208-5, which are arranged at specific intervals at the bottom, can be controlled individually. Each flow rate is controlled by an operating valve installed in the liquefied monomer-containing liquid supply pipe and the recycle gas supply pipe, respectively. The polymer particles move from the upstream to the downstream end of the reactor while reacting and mixing, and are discharged out of the reaction system through the polymer extraction pipe 213.

[0102] The location for supplying the electron-donating compound, which is liquid at standard conditions, is any location within the range from 0% to 66% of the longitudinal direction from the furthest downstream end of the final horizontal reactor to the 66% upstream end, as shown in Figure 2. This range corresponds to the distance from the furthest downstream end (location of partition wall 210b) to the upstream end (location of partition wall 210a), where the location of partition wall 210b is 0% and the location of partition wall 210a is 100%. The location for supplying the electron-donating compound, which is liquid at standard conditions, into the reactor may be any location within the range from the furthest downstream end of the final horizontal reactor to 50% of the longitudinal direction, and further, any location within the range from the furthest downstream end of the final horizontal reactor to 34% of the longitudinal direction. The location for supplying the electron-donating compound, which is liquid at standard conditions, is not limited to one location, but may be two or more locations. When supplying from two or more locations, the electron-donating compounds may be the same or different. This method enhances the suppression of deposits that tend to form on the stirring blades and walls downstream, and suppresses quality deterioration due to the detachment of deposits during operation. Therefore, it may include supplying an electron-donating compound, which is liquid at standard conditions, into the reactor at any point between the furthest downstream end in the longitudinal direction of the final horizontal reactor and 50% upstream, or supplying an electron-donating compound, which is liquid at standard conditions, into the reactor at any point between the furthest downstream end in the longitudinal direction of the final horizontal reactor and 34% upstream.

[0103] Furthermore, it is preferable to supply electron-donating compounds, which are liquid at standard conditions, into the reactor along with liquefied propylene. Electron-donating compounds, which are liquid at standard conditions, may be supplied into the reactor along with liquefied propylene from liquid supply pipes containing liquefied monomers, which are arranged at specific intervals at the top. Specifically, for example, in Figure 2, electron-donating compounds, which are liquid at standard conditions, may be supplied into the reactor from 215-2, 215-3, and 215-4, such that liquefied propylene and electron-donating compounds, which are liquid at standard conditions, are supplied from 207-3, 207-4, and 207-5, which are located between the furthest downstream end and 66% upstream.

[0104] In addition, the second polymerization step may include supplying the electron-donating compound, which is liquid at standard conditions, to the final horizontal reactor at any point between the furthest downstream end in the longitudinal direction of the final horizontal reactor and 66% upstream; however, the electron-donating compound, which is liquid at standard conditions, may be supplied at any other location.

[0105] In the present invention, as the electron-donating compound that is liquid under standard conditions, a compound with a molecular weight of 30 to 80 is preferred, in order to reduce the amount of electron-donating compound used and to facilitate the removal of the electron-donating compound after polymerization. As the electron-donating compound that is liquid under standard conditions, in order to suppress odor, it may be at least one compound selected from the group consisting of methanol, ethanol, isopropyl alcohol, acetone, and methyl acetate, and may be ethanol.

[0106] The supply amounts of these electron-donating compounds are not particularly limited. The supply amount of electron-donating compounds that are liquid at standard conditions in the second polymerization step may be 0.5 to 20 times the molar amount of the organoaluminum compound (B) in the first polymerization step. When supplying electron-donating compounds that are liquid at standard conditions in the second polymerization step from two or more locations, it is preferable that the total amount satisfies the above range. That is, in the second polymerization step, when supplying electron-donating compounds that are liquid at standard conditions at any location within the range from the furthest downstream end of the final horizontal reactor to 66% upstream, it is preferable that the total amount satisfies the above range when supplying them from two or more locations within the above range. Furthermore, when supplying electron-donating compounds that are liquid at standard conditions at locations other than the range from the furthest downstream end of the final horizontal reactor to 66% upstream in the longitudinal direction in the second polymerization step, it is preferable that the total amount, including the supply amount of electron-donating compounds at the other locations, satisfies the above range. However, the amount of the electron-donating compound, which is liquid at standard conditions, supplied to any point between the furthest downstream end in the longitudinal direction of the final horizontal reactor and 66% upstream may be 50 mol% to 100 mol%, preferably 70 mol% to 100 mol%, more preferably 85 mol% to 100 mol%, or even 100 mol% of the total amount. The amount of the electron-donating compound, which is liquid at standard conditions, supplied in the second polymerization step may be more preferably 0.8 times the mole or more, even more preferably 1 time the mole or more, preferably 10 times the mole or less, more preferably 5 times the mole or less, or even 2 times the mole or less, relative to the organoaluminum compound (B) in the first polymerization step, from the viewpoint of reducing gel and fish-eye formation and suppressing the decrease in polymerization activity.

[0107] Furthermore, in the present invention, the oxygen concentration in the reactor is less than 0.60 mol ppm in the second polymerization step. When two or more reactors are used in the second polymerization step, the oxygen concentration in all reactors is adjusted to be less than 0.60 mol ppm. Oxygen can act as a polymerization activity inhibitor, and has conventionally been used as a gaseous polymerization activity inhibitor under standard conditions. Also, the oxygen concentration in the reactor in the second polymerization step may increase due to a decrease in the purity of the raw material monomer or deterioration of the purification column. In the second polymerization step, from the viewpoint of odor suppression, the oxygen concentration in the reactor may be less than 0.40 mol ppm, less than 0.20 mol ppm, less than 0.10 mol ppm, or less than 0.01 mol ppm. In the present invention, in order to keep the oxygen concentration in the reactor less than 0.60 mol ppm in the second polymerization step, it is preferable not to supply oxygen to the second polymerization step. Furthermore, the oxygen concentration in the reactor being less than 0.60 mol ppm can be confirmed by measuring the gas sampled from the reactor using a trace oxygen analyzer. Specifically, the measurement of the oxygen concentration in the reactor can be carried out by the method described in the examples below.

[0108] 3. Propylene Block Copolymers Produced The propylene block copolymers produced by the present invention can have their melt flow rate (MFR) controlled by using a molecular weight modifier such as hydrogen during the polymerization process in the first polymerization step, either in the propylene homopolymerization or copolymerization of propylene with other α-olefins. The MFR of the first propylene polymer is set according to the molding method and application, but the MFR value (unit: g / 10 min) measured under measurement conditions of 230°C and a 2.16 kg load is usually 0.1 or higher, may be 1 or higher, may be 10 or higher, may be 500 or lower, may be 100 or lower, and more preferably 50 or lower. If the MFR is too low, the fluidity of the polymer will decrease significantly, making molding difficult, and if it is too high, a decrease in tensile properties may occur.

[0109] In the second step, the melt flow rate (MFR) of the propylene-based block copolymer can be controlled by adjusting the polymerization amount and using molecular weight modifiers such as hydrogen during the polymerization process. The MFR of the propylene-based block copolymer is set according to the molding method and application, but the MFR value (unit: g / 10 min) measured under measurement conditions of 230°C and a 2.16 kg load is usually 0.1 or higher, may be 1 or higher, may be 5 or higher, may be 10 or higher, may be 500 or lower, may be 100 or lower, and more preferably 50 or lower.

[0110] Furthermore, from the viewpoint of odor suppression, the propylene-based block copolymer produced in the present invention preferably has a total amount of alcohol components with 4 or more carbon atoms measured by gas chromatography analysis of 6 ng or less per gram of propylene-based block copolymer, and may also be 2 ng or less. The total amount of alcohol components with 4 or more carbon atoms in the propylene-based block copolymer can be measured by gas chromatography, specifically by the method described in the examples below. In addition, the propylene-based block copolymer produced in the present invention is preferably odorless in sensory tests. The sensory tests can be specifically performed by the method described in the examples below.

[0111] The propylene-based block copolymer obtained by the manufacturing method of the present invention can be used, for example, in injection molding, extrusion molding, etc., and is suitable for automotive, food, and medical applications, and is particularly suitable for automotive materials.

[0112] The present invention will be described in more detail below using examples, but the present invention is not limited to these examples. The method for measuring each physical property value in the present invention is shown below. [Measurement of various physical properties] (1) MFR The propylene polymer obtained in the examples was evaluated under conditions in accordance with JIS K7210 (230°C, 2.16 kg load). (2) Structure determination of block copolymer The ratio of the first propylene polymer to the second propylene polymer was determined from the production rate (R1) of the first propylene polymer obtained in the first polymerization step and the production rate (R2) of the propylene block copolymer obtained in the second polymerization step, by the following formulas: Ratio of the first propylene polymer (W1) = R1 / R2 × ​​100 Ratio of the second propylene polymer (W2) = (R2 - R1) / R2 × ​​100 The ethylene content (C mass%) of the first propylene polymer was determined by NMR after sampling a portion of the first propylene polymer obtained in the first polymerization step. The ethylene content (A mass%) of the propylene block copolymer was determined by NMR after sampling a portion of the propylene block copolymer obtained in the second polymerization step. The ethylene content of the second propylene polymer was determined by the formula (A × 100 - C × W1) / W2.

[0113] (3) Gel evaluation method (number of bright spots) (number of gels / g) 2 kg of propylene block copolymer powder was mixed with 0.002 kg of 2,6-di-t-butyl-p-cresol and 0.002 kg of calcium stearate using a high-speed agitator (Henschel mixer (product name)) for 2 minutes at room temperature, and the mixture was granulated using an extruder with a screw diameter of 40 mm. The obtained pellets were used to create a 50 mm x 50 mm sheet with a thickness of 0.5 mm using an injection molding machine (Niigata Iron Works, model: NN30-H4000), and the number of gels present on the sheet was counted visually. The results were summarized as the number of gels per 1 g of sheet.

[0114] (4) Odor evaluation using analytical instrument (HS / SPME-GC / MS) Approximately 2 g of polymer obtained by polymerization was weighed into a 20 mL headspace (HS) vial (Gester, 093640-006-00), and the vial was capped (septum-integrated cap: Gester, 093640-063-00). These vials were placed in a block heater (Gester, agitator attached to MPS), and a solid-phase microextraction (SPME) fiber (Spelco, 85 μm CAR / PDMS) was inserted into the gas phase of the vial. The vial was heated at 60°C for 60 minutes. During this time, volatile components generated from the polymer were collected on the SPME fiber. The components collected on the SPME fiber were thermally desorbed at the temperature of the GC inlet and introduced into the GC column. The components separated by the GC column were directed to a mass spectrometer (MS) and an olfactory detection port (Gester, ODP3) using a partition (Agilent, 2-way flow channel splitter) before the detector, and GC / MS (Agilent, 7890GC / Agilent, 5975MSD) measurements were performed. Here, the split ratio between MS and ODP3 was set to MS:ODP3 = ​​1:2. At this time, the hold-up time from the partition was 0.4 seconds for MS and 0.5 seconds for ODP3. Standard solutions of toluene (Fujifilm Wako Pure Chemical Industries, reagent grade) at concentrations of approximately 30, 60, and 120 μg / mL were prepared using acetone (Fujifilm Wako Pure Chemical Industries, reagent grade) as the solvent. One μL of these solutions was added to a 20 mL HS vial, and GC / MS measurements were performed under the same conditions as the sample.

[0115] (5) Odor evaluation by sensory testing (HS / SPME-ODP3) In the same manner as in (4) above, the components separated by the GC column were directed to a mass spectrometer (MS) and an olfactory detection port (Gester, ODP3) using a partition (Agilent, 2-way flow channel splitter) before the detector, and the odor was evaluated using the olfactory detection port (Gester, ODP3).

[0116] (6) Oxygen concentration in the reactor The oxygen concentration in the reactor was determined by measuring the gas sample taken from the unreacted gas extraction pipe of the reactor into a gas cylinder using a trace oxygen analyzer (Servomex Corporation) and taking the average of multiple measurements.

[0117] [Catalyst Production Example] (1) Preparation of Olefin Polymerization Catalyst Component (A) Preparation of Solid Component A 10 L autoclave equipped with a stirring device was thoroughly purged with nitrogen, and 2 L of purified toluene was introduced. Here, at room temperature, Mg(OEt) ２ 200g of TiCl ４ 1 L of [the substance] was added. The temperature was raised to 90°C, and 40 ml of di-n-butyl phthalate and 10 ml of diethyl phthalate were introduced. Then, the temperature was raised to 110°C and the reaction was carried out for 3 hours. The reaction product was thoroughly washed with purified toluene. Next, purified toluene was introduced to adjust the total volume to 2 L. TiCl at room temperature ４ 1 L of was added, and the temperature was raised to 110°C for 2 hours to carry out the reaction. The reaction product was thoroughly washed with purified toluene. Then, purified toluene was added to adjust the total volume to 2 L. TiCl at room temperature ４ 1 L of was added, and the temperature was raised to 110°C for a 2-hour reaction. The reaction product was thoroughly washed with purified toluene. Furthermore, toluene was replaced with n-heptane using purified n-heptane to obtain a slurry of solid components. A portion of this slurry was sampled, dried, and analyzed, and the Ti content of the solid components was found to be 1.7% by mass. Next, a 20 L autoclave equipped with a stirring device was thoroughly purged with nitrogen, and 100 g (0.036 mol Ti) of the above solid component slurry was introduced as the solid component. Purified n-heptane was introduced to adjust the concentration of the solid component to 25 g / L. SiCl ４ 50 ml of was added and the reaction was carried out at 90°C for 1 hour. After thoroughly washing the reaction product with purified n-heptane, purified n-heptane was introduced to adjust the liquid level to 4 L. Herein, [CH4] ２ =CH-] ２ SiMe ２ 25 ml of (i-Pr) ２ Si(OMe) ２18 ml of [the solution] was added, along with 40 g (0.35 mol) of a dilution of triethylaluminum in n-heptane, and the reaction was carried out at 40°C for 2 hours. The reaction product was thoroughly washed with purified n-heptane to obtain a slurry of the solid catalyst component (olefin polymerization catalyst component (A)). A portion of the obtained slurry was sampled, dried, and analyzed, and it was found that the solid catalyst component contained 1.2% by mass of Ti, (i-Pr) ２ Si(OMe) ２ It contained 6.7% by mass.

[0118] (2) Prepolymerization activation treatment of olefin polymerization catalyst component (A) Prepolymerization was carried out using 100 g (0.025 mol Ti) of the solid catalyst component obtained above, according to the following procedure. Purified n-heptane was introduced into the slurry to adjust the concentration of the solid catalyst component to 20 g / L. After cooling the slurry to 10°C, 15 g (0.132 mol) of a dilution of triethylaluminum in n-heptane was added as triethylaluminum, and 280 g of propylene was supplied over 4 hours. After the supply of propylene was completed, the reaction was continued for another 30 minutes. Next, the gas phase was thoroughly replaced with nitrogen and the reaction product was thoroughly washed with purified n-heptane. The obtained slurry was removed from the autoclave and vacuum dried to obtain the prepolymerized solid catalyst component. Analysis of this prepolymerized solid catalyst component revealed that it contained 2.0 g of polypropylene per gram of solid catalyst component (olefin polymerization catalyst component (A)), and the portion of this solid catalyst component excluding the polypropylene contained 1.2 mass% Ti, (i-Pr) ２ Si(OMe) ２ It contained 6.4% by mass.

[0119] (Example 1) 1. First polymerization process This will be explained by referring to the flow sheet shown in Figure 1 attached. After replacing the horizontal reactor 100, which has stirring blades, with nitrogen gas, seed powder was introduced and nitrogen gas was circulated. Thereafter, the temperature was raised while introducing propylene and hydrogen, and when the polymerization conditions were met, 540 g / hr of the pre-polymerized olefin polymerization catalyst component (A) was supplied from the catalyst component supply pipe 101, and triethylaluminum as an organoaluminum compound (B) was continuously supplied from the catalyst component supply pipe 102 so that the Al / Mg ratio (molar ratio) with respect to the Mg in the olefin polymerization catalyst component (A) was 7.5. When the position of the partition wall 100a of the horizontal reactor 100 is considered the upstream end of the reactor, the temperature was controlled by supplying liquefied propylene from the liquefied monomer-containing liquid supply pipes 107-1 to 107-5, respectively, so that the thermometers, which are installed at the same distance from the upstream end as the recycled gas supply pipes 108-1 to 108-5, read 59°C, 59°C, 62°C, 64°C, and 65°C from upstream. In addition, while maintaining a reaction pressure of 2.45 MPaG, hydrogen gas was continuously supplied from the hydrogen supply pipe 104-1 to adjust the MFR of the first propylene-based polymer (propylene homopolymer) so that the hydrogen concentration in the gas phase inside the reactor was maintained at the hydrogen / propylene molar ratio shown in Table 1.

[0120] The unreacted gas discharged from the horizontal reactor 100 was cooled and condensed outside the horizontal reactor 100 system through the unreacted gas extraction pipe 110, and then refluxed back into the horizontal reactor 100 through the liquefied monomer-containing liquid supply pipes 107-1, 107-2, 107-3, 107-4, and 107-5. The generated first propylene polymer was intermittently extracted from the extraction pipe 113 at the downstream end of the horizontal reactor 100, transferred via the vessel 114, and then through the transfer pipe 201 to the horizontal reactor 200 for the second polymerization step.

[0121] 2. In the second polymerization step, the first propylene polymer transferred from the first polymerization step (horizontal polymerizer) and ethylene were supplied from piping 204-2 to a horizontal reactor 200 equipped with a stirring blade, and copolymerization was carried out with a mixed gas containing ethylene and propylene. The reaction conditions were controlled by supplying liquefied propylene from liquefied monomer-containing liquid supply pipes 207-1 to 207-5 so that when the partition wall 210a of the horizontal reactor 200 was considered the upstream end of the reactor, the thermometers installed at the same position as the recycled gas supply pipes 208-1 to 208-5 read 63°C. In addition, while maintaining a reaction pressure of 2.40 MPaG, the gas composition in the gas phase was adjusted to the ethylene / propylene ratio and hydrogen / propylene ratio shown in Table 1. To regulate the polymerization amount of the propylene-ethylene copolymer, ethanol (an electron-donating compound that is liquid at standard conditions) was supplied together with liquefied propylene from pipe 215-2 (located 60% upstream from the downstream end when the partition wall 210b of the horizontal reactor is considered the downstream end), and hydrogen gas was supplied from pipe 204-1 to adjust the molecular weight of the copolymer.

[0122] The unreacted gas discharged from the horizontal reactor 200 was cooled and condensed outside the horizontal reactor 200 system through the unreacted gas extraction pipe 210, and then refluxed back into the horizontal reactor 200 through the liquefied monomer-containing liquid supply pipes 207-1, 207-2, 207-3, 207-4, and 207-5. The propylene-based block copolymer produced in the second polymerization step (horizontal reactor 200) was intermittently extracted through the extraction pipe 213 at the downstream end of the horizontal reactor 200. In the second polymerization step, no oxygen was added to the reactor as a polymerization activity inhibitor, and the oxygen concentration in the reactor was 0.40 mol ppm. The production rate of the propylene-based block copolymer was 25,700 kg / hr.

[0123] The extracted propylene-based block copolymer (product powder) had unreacted monomers removed, and a portion was subjected to MFR measurement and various analyses. Furthermore, a portion of the granulated propylene-based block copolymer (product pellets) was subjected to bright spot measurement, analysis of alcohol components with four or more carbon atoms that cause odor, and odor analysis by sensory testing. The results are shown in Table 2. No alcohols with four or more carbon atoms other than those listed in Table 2 were detected (this was consistent across all examples and comparative examples). Furthermore, the odor analysis by sensory testing was odorless.

[0124] [Example 2] In the second polymerization step, ethanol (an electron-donating compound that is liquid at standard conditions) was supplied together with liquefied propylene from pipes 215-2 and 215-3 (at positions 60% and 50% upstream from the downstream end when the partition wall 210b of the horizontal reactor is the downstream end) as a polymerization activity inhibitor to adjust the polymerization amount of the propylene-ethylene copolymer, and the polymerization conditions shown in Table 1 were changed. Otherwise, a propylene-based block copolymer was produced in the same manner as in Example 1. The polymerization conditions are shown in Table 1. In the second polymerization step, the oxygen concentration in the reactor was 0.40 mol ppm. The results are shown in Table 2.

[0125] [Example 3] In the second polymerization step, ethanol (an electron-donating compound that is liquid at standard conditions) was supplied together with liquefied propylene from pipes 215-3 and 215-4 (located at 50% and 33% upstream from the downstream end when the partition wall 210b of the horizontal reactor is the downstream end) as a polymerization activity inhibitor to adjust the polymerization amount of the propylene-ethylene copolymer, and the polymerization conditions shown in Table 1 were changed. Otherwise, a propylene-based block copolymer was produced in the same manner as in Example 1. The polymerization conditions are shown in Table 1. In the second polymerization step, the oxygen concentration in the reactor was 0.20 mol ppm. The results are shown in Table 2.

[0126] [Example 4] In the second polymerization step, ethanol (an electron-donating compound that is liquid at standard conditions) was supplied together with liquefied propylene from pipes 215-2, 215-3, and 215-4 (located at 60%, 50%, and 33% upstream from the downstream end when the partition wall 210b of the horizontal reactor is the downstream end) as a polymerization activity inhibitor to adjust the polymerization amount of the propylene-ethylene copolymer, and the polymerization conditions shown in Table 1 were changed. Otherwise, a propylene-based block copolymer was produced in the same manner as in Example 1. The polymerization conditions are shown in Table 1. In the second polymerization step, the oxygen concentration in the reactor was 0.10 mol ppm. The results are shown in Table 2.

[0127] [Comparative Example 1] In the second polymerization step, ethanol (an electron-donating compound that is liquid at standard conditions) was supplied from pipe 215-1 (at positions 80% and 90% upstream from the downstream end when the partition wall 210b of the horizontal reactor is the downstream end) as a polymerization activity inhibitor to adjust the polymerization amount of the propylene-ethylene copolymer, and oxygen was supplied from pipe 214 as a polymerization activity inhibitor. The pressure in the first polymerization step was changed to 2.0 MPaG, the pressure in the second polymerization step to 1.9 MPaG, and the production rate to 15.3 kg / h. The polymerization conditions shown in Table 1 were also changed, but otherwise a propylene-based block copolymer was produced in accordance with Example 1. The polymerization conditions are shown in Table 1. In the second polymerization step, the oxygen concentration in the reactor was 1.00 mol ppm. The results are shown in Table 2. A pungent odor was detected in the odor analysis by sensory testing.

[0128] [Comparative Example 2] In the second polymerization step, ethanol was not supplied as a polymerization activity inhibitor to adjust the polymerization amount of the propylene-ethylene copolymer; instead, oxygen was supplied from pipe 214. Except for this, the propylene-based block copolymer was produced in accordance with Comparative Example 1. The polymerization conditions are shown in Table 1. In the second polymerization step, the oxygen concentration in the reactor was 5.00 mol ppm. The results are shown in Table 2.

[0129]

[0130] In the table, "N.D." means not detected, and "trace" means less than 0.1 ng / g-PP.

[0131] In Comparative Examples 1 and 2, the propylene-based block copolymers obtained by methods that did not satisfy the specific requirements of the manufacturing method of the present invention, namely, "the second polymerization step includes supplying an electron-donating compound, which is liquid at standard conditions, to the final horizontal reactor at any point between the furthest downstream end in the longitudinal direction of the final horizontal reactor and 66% upstream, and the oxygen concentration in the reactor is less than 0.60 mol ppm," had an increased amount of alcohol components with four or more carbon atoms, which cause odor, and possessed a pungent odor. In contrast, in Examples 1 to 4, which used a manufacturing method that satisfies the requirements of the present invention, namely "the supply of an electron-donating compound that is liquid at standard conditions to the final horizontal reactor in the second polymerization step, at any point between the furthest downstream end of the final horizontal reactor in the longitudinal direction and 66% upstream, and the concentration of a polymerization activity inhibitor that is gaseous at standard conditions in the reactor in the second polymerization step being less than 0.60 mol ppm," it was revealed that the method was a method for producing propylene-based block copolymers in which alcohol components with 4 or more carbon atoms, which cause odor, were hardly detected, gel and fish-eye defects were reduced, and odor was suppressed. Furthermore, in Comparative Example 1, a large amount of deposits were observed on the stirring blades and walls downstream of the final horizontal reactor, and the amount of deposits was particularly large in Comparative Example 2. In contrast, in Examples 1 to 4, there was less deposit on the stirring blades and walls downstream of the final horizontal reactor, demonstrating that quality deterioration due to deposit detachment during operation was suppressed. Therefore, the manufacturing method of the present invention yields excellent results in that it can produce propylene-based block copolymers with reduced gel and fish eyes, and suppressed odor. Furthermore, it can suppress quality deterioration due to the detachment of adhering substances during operation, and thus has great technical significance.

[0132] In the manufacturing method of the present invention, a propylene-based crystalline polymer is produced in the first polymerization step, and an amorphous copolymer of propylene and α-olefins excluding propylene is produced in the second polymerization step. This allows for the continuous production of propylene-based block copolymers with high rigidity and high impact strength, and reduced gel and fish-eye properties, with high production efficiency and without the generation of alcohol components with four or more carbon atoms that cause odors, making it highly useful in industry.

[0133] 100 Horizontal reactor (first reactor) D Reactor diameter 100a, 100b Partition 101 Catalyst component supply piping 102 Catalyst component supply piping 103 Raw material monomer supply piping 104-1, 104-2 Raw material hydrogen supply piping 105 Condenser 106-1, 106-2 Piping 107-1, 107-2, 107-3, 107-4, 107-5 Liquefied monomer-containing liquid supply piping 108, 108-1, 108-2, 108-3, 108-4, 108-5 Recycle gas supply piping 109 Agitator 109a Horizontal shaft 109b Agitator blade 110 Unreacted gas extraction piping 111 Recycle drum 112 Compressor 113 Polymer extraction piping 114 Vessel 201 Transfer piping 200 Horizontal reactor (second reactor) 210a, 210b Partition 202 Catalyst component supply piping 203 Raw material monomer supply piping 204-1 Raw material hydrogen supply piping 204-2 Raw material ethylene supply piping 205 Condenser 206-1, 206-2 Piping 207-1, 207-2, 207-3, 207-4, 207-5 Liquefied monomer-containing liquid supply piping 208, 208-1, 208-2, 208-3, 208-4, 208-5 Recycle gas supply piping 209 Agitator 209a Horizontal shaft 209b Agitator blade 210 Unreacted gas extraction piping 211 Recycle drum 212 Compressor 213 Polymer extraction piping 214 Oxygen supply piping 215-1 Liquid electron donor supply piping (located more than 66% upstream from the furthest downstream end) 215-2, 215-3, 215-4 Liquid electron donor supply piping (located up to 66% upstream from the furthest downstream end)

Claims

1. A polymerization step comprising: a first polymerization step of producing at least one first propylene polymer (provided that the propylene content of the first propylene polymer exceeds 95% by mass) selected from a propylene homopolymer and a copolymer of propylene and at least one monomer selected from the group consisting of α-olefins other than propylene, using one or more reactors in the presence of a catalyst containing an olefin polymerization catalyst component (A) and an organoaluminum compound (B); and a second polymerization step of producing a second propylene polymer, comprising polymerizing a copolymer of propylene with a propylene content of 95% by mass or less and at least one monomer selected from the group consisting of α-olefins other than propylene, using one or more reactors including a horizontal reactor in the presence of the first propylene polymer, wherein the second polymerization step includes supplying an electron-donating compound, which is liquid at standard conditions, to the final horizontal reactor at any point between the furthest downstream end in the longitudinal direction of the final horizontal reactor and 66% upstream. A method for producing a propylene-based block copolymer, wherein the oxygen concentration in the reactor is less than 0.60 mol ppm in the second polymerization step.

2. The method for producing a propylene-based block copolymer according to claim 1, comprising supplying an electron-donating compound, which is liquid at standard conditions, into the reactor at any point between the furthest downstream end in the longitudinal direction of the final horizontal reactor and 50% upstream.

3. The method for producing a propylene-based block copolymer according to claim 1, comprising supplying an electron-donating compound, which is liquid at standard conditions, into the reactor at any point between the furthest downstream end in the longitudinal direction of the final horizontal reactor and 34% upstream in the second polymerization step.

4. The method for producing a propylene-based block copolymer according to claim 1, wherein the amount of electron-donating compound supplied in the second polymerization step is 0.5 to 20 moles relative to the organoaluminum compound (B) in the first polymerization step.

5. The method for producing a propylene-based block copolymer according to claim 1, wherein the electron-donating compound, which is liquid under standard conditions, is at least one compound selected from the group consisting of methanol, ethanol, isopropyl alcohol, acetone, and methyl acetate.

6. The method for producing a propylene-based block copolymer according to claim 1, wherein at least one of the first polymerization step and the second polymerization step is a gas-phase polymerization step.

7. The method for producing a propylene-based block copolymer according to claim 6, wherein the gas-phase polymerization step is a gas-phase polymerization step in which the reaction heat is removed mainly by the heat of vaporization of liquefied propylene.

8. A method for producing a propylene-based block copolymer according to any one of claims 1 to 7, wherein the propylene-based block copolymer produced is odorless in a sensory test.

9. A method for producing a propylene-based block copolymer according to any one of claims 1 to 7, wherein the total amount of alcohol components having 4 or more carbon atoms as determined by gas chromatography analysis of the propylene-based block copolymer produced is 6 ng or less per 1 g of propylene-based block copolymer.

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