Method for producing propylene-based block copolymer

Abstract

To provide a method for easily producing a propylene-based block copolymer that has a high melt flow rate and a high content ratio of a propylene / α-olefin copolymer component, the method having excellent polymerization activity in a first polymerization step and a second polymerization step.SOLUTION: This method for producing a propylene-based block copolymer includes: a first polymerization step for obtaining a propylene-based polymer by polymerizing olefins that include 95-100 mass% of propylene under the temperature condition of 45°C to 65°C using an olefin polymerization catalyst comprising (A) a solid catalyst component for olefin polymerization which contains titanium, magnesium, a halogen and a 1,3-diether compound, and (B) an organoaluminum compound; and subsequently, a second polymerization step for obtaining a propylene / α-olefin copolymer by copolymerizing olefins that include 5 mass% or more and less than 95 mass% of propylene and an α-olefin excluding propylene in the presence of the propylene-based polymer under the temperature condition of 50°C to 90°C.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a method for producing a propylene-based block copolymer.

Background Art

[0002] Conventionally, olefins such as propylene have been polymerized using a catalyst for olefin polymerization. In particular, a propylene-based block copolymer polymerized using a catalyst for olefin polymerization has been preferably used because of its excellent balance between rigidity and impact resistance.

[0003] Among propylene-based block copolymers, ethylene-propylene block copolymers in particular have good mechanical properties such as rigidity and heat resistance and can be produced at relatively low cost, and thus are applied to a wide range of uses.

[0004] This ethylene-propylene block copolymer means a blend of a propylene-based polymer mainly composed of propylene and a random copolymer of propylene and ethylene. Generally, it is produced by sequentially performing polymerization under conditions corresponding to the polymer to be obtained and blending each polymer in a reaction vessel.

[0005] For example, as a polymerization reaction for obtaining an ethylene-propylene block copolymer, a homopolymerization reaction of propylene or a random copolymerization reaction of propylene and a small amount of ethylene is carried out in the first stage, and in the presence of the obtained propylene-based polymer, a copolymerization reaction of propylene and ethylene is carried out in the second stage. This is preferably carried out. The ethylene-propylene block copolymer obtained by the above method is melted and then molded by various molding machines, stretching machines, etc., and is used for various applications such as molded products for automobile parts and home appliance parts, as well as containers and sheets.

[0006] As an olefin polymerization catalyst used in the production of the above propylene-based block copolymer, an olefin polymerization catalyst containing a solid catalyst component containing a magnesium atom, a titanium atom, a halogen atom, and an internal electron-donating compound such as a phthalic acid ester as essential components, an organoaluminum compound, and an organosilicon compound which is an external electron-donating compound has been proposed in many cases (see, for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0007]

Patent Document 1

Disclosure of the Invention

Problems to be Solved by the Invention

[0008] Since the above ethylene-propylene block copolymer is frequently used for injection molding of automobile bumpers and the like, in order to improve the productivity of the injection molding process, those having excellent melt flow rate (hereinafter also referred to as MFR) are desired.

[0009] Also, in order to increase the impact strength of the ethylene-propylene block copolymer, it is necessary to set the content ratio of the random copolymer component to a certain value or more. Further, since most of the ethylene constituting the ethylene-propylene block copolymer is incorporated into the random copolymer and the amount of crystalline polyethylene is required to be small, a technique in which the polymerization activity during the formation of the random copolymer of propylene and ethylene which is the rubber part is high and ethylene is efficiently introduced into the random copolymer is desired.

[0010] By the way, as described above, a method for producing an ethylene-propylene block copolymer in which a propylene-based polymer component mainly composed of propylene is produced in the first polymerization step and propylene and ethylene are randomly copolymerized in the presence of the above propylene-based polymer in the second polymerization step is known. In the above polymerization reaction, generally, if the polymerization activity in the first polymerization step becomes too high, the polymerization activity in the second polymerization step becomes difficult to increase. As a result, in the obtained propylene-based block copolymer, the content ratio of the propylene / ethylene random copolymer component tends to decrease.

[0011] In order to solve the above technical problems, the inventor of the present invention conceived of suppressing the polymerization temperature in the first polymerization step to a temperature lower than the normal polymerization temperature and suppressing the polymerization activity in the first polymerization step, thereby increasing the polymerization activity in the second polymerization step.

[0012] However, when the inventor examined, when using an olefin polymerization catalyst containing a phthalic acid ester as an internal electron donor compound as described in Patent Document 1 and suppressing the polymerization temperature in the first polymerization step to a temperature lower than the normal polymerization temperature, it was found that the yield of the obtained ethylene-propylene block copolymer also decreased.

[0013] In addition, an olefin polymerization catalyst containing a phthalic acid ester as an internal electron donor compound as described in Patent Document 1 hardly gives an ethylene-propylene block copolymer excellent in melt flow rate (MFR) when used for the polymerization of olefins.

[0014] In addition, when trying to improve the polymerization activity in the second polymerization step to obtain an ethylene-propylene block copolymer having a high content ratio of the propylene / ethylene random copolymer, usually, as the content ratio of the propylene / ethylene random copolymer increases, the fluidity of the obtained ethylene-propylene block copolymer decreases, and it was difficult to obtain an ethylene-propylene block copolymer having a sufficient melt flow rate (MFR).

[0015] Under such circumstances, an object of the present invention is to provide a method for easily producing a propylene-based block copolymer that has excellent polymerization activity in the first polymerization step of performing a homopolymerization reaction of propylene or a copolymerization reaction of propylene and a small amount of α-olefin (excluding propylene), and also has excellent polymerization activity in the second polymerization step of performing a copolymerization reaction of propylene and α-olefin (excluding propylene) in the presence of the propylene-based polymer obtained in the first polymerization step, and has a melt flow rate that is sufficiently high in practical use and a high content ratio of the propylene / α-olefin copolymer.

Means for Solving the Problems

[0016] To solve the above technical problems, the inventors of the present invention conducted intensive studies. As a result, by using an olefin polymerization catalyst containing (A) a solid catalyst component for olefin polymerization containing titanium, magnesium, halogen, and a 1,3-diether compound which is an internal electron donor compound, and (B) an organoaluminum compound, and performing a first polymerization step of polymerizing olefins containing 95 to 100% by mass of propylene under a temperature condition of 45°C to 65°C to obtain a propylene-based polymer, and then further performing a second polymerization step of copolymerizing olefins containing 5% by mass or more and less than 95% by mass of propylene and an α-olefin excluding propylene in the presence of the propylene-based polymer under a temperature condition of 50°C to 90°C to obtain a propylene / α-olefin copolymer, it was found that the above problems can be solved, and the present invention was completed.

[0017] That is, the present invention provides: (1) Using an olefin polymerization catalyst containing (A) a solid catalyst component for olefin polymerization containing titanium, magnesium, halogen, and a 1,3-diether compound which is an internal electron donor compound, and (B) an organoaluminum compound, after performing a first polymerization step of polymerizing olefins containing 95 to 100% by mass of propylene under a temperature condition of 45°C to 65°C to obtain a propylene-based polymer, Furthermore, a second polymerization step is performed in which olefins containing 5% by mass or more and less than 95% by mass of propylene and an α-olefin excluding propylene are copolymerized in the presence of the propylene-based polymer under a temperature condition of 50°C to 90°C to obtain a propylene / α-olefin copolymer. A method for producing a propylene-based block copolymer, characterized by the above, (2) The (B) organoaluminum compound is represented by the following general formula (I) R 1 p AlQ 3-p (I) (In the formula, R 1 is an alkyl group having 1 to 6 carbon atoms, Q is a hydrogen atom or a halogen atom, p is 0 < p ≤ 3, and when there are a plurality of R 1 , each R 1 may be the same as or different from each other, and when there are a plurality of Q, each Q may be the same as or different from each other.) is one or more compounds represented by The method for producing a propylene-based block copolymer according to the above (1), (3) The method for producing a propylene-based block copolymer according to the above (1) or (2), wherein the olefin polymerization catalyst further contains (C) an external electron donor compound. (4) The method for producing a propylene-based block copolymer according to any one of the above (1) to (3), wherein in the obtained propylene-based block copolymer, the content ratio of the propylene / α-olefin part is 25.0 to 50.0% by mass. is provided.

Effects of the Invention

[0018] According to the present invention, there is provided a method capable of easily producing a propylene-based block copolymer that has excellent polymerization activity in the first polymerization step of performing a homopolymerization reaction of propylene or a copolymerization reaction of propylene and a small amount of α-olefin (excluding propylene), is excellent in polymerization activity in the second polymerization step of performing a copolymerization reaction of propylene and an α-olefin (excluding propylene) in the presence of the propylene-based polymer obtained in the first polymerization step, has a melt flow rate sufficiently high in practical use, and has a high content ratio of the propylene / α-olefin copolymer component.

Embodiments for Carrying Out the Invention

[0019] First, the method for producing a propylene-based block copolymer according to the present invention will be described. The method for producing a propylene-based block copolymer according to the present invention is (A) a solid catalyst component for olefin polymerization containing titanium, magnesium, halogen, and a 1,3-diether compound which is an internal electron donor compound, (B) an organoaluminum compound and using a catalyst for olefin polymerization containing the same, After performing a first polymerization step of polymerizing olefins containing 95 to 100% by mass of propylene at a temperature condition of 45°C to 65°C to obtain a propylene-based polymer, Furthermore, at a temperature condition of 50°C to 90°C, a second polymerization step of copolymerizing olefins containing 5% by mass or more and less than 95% by mass of propylene and an α-olefin excluding propylene in the presence of the propylene-based polymer to obtain a propylene / α-olefin copolymer is performed which is characterized by the above.

[0020] In the method for producing a propylene-based block copolymer according to the present invention, examples of the solid catalyst component for olefin polymerization containing titanium, magnesium, halogen, and a 1,3-diether compound which is an internal electron donor compound include contact reaction products obtained by bringing a raw material component serving as a supply source of magnesium, titanium, and halogen and an internal electron donor compound containing a 1,3-diether compound into contact with each other and reacting them in an organic solvent. As the above-mentioned solid catalyst component for olefin polymerization, specifically, as raw material components serving as sources of magnesium, titanium, and halogen, a magnesium compound and a tetravalent titanium halogen compound are used, and examples thereof include contact reactants obtained by bringing these raw material components into contact with an internal electron-donating compound containing a 1,3-diether compound.

[0021] Examples of the above-mentioned magnesium compound include one or more selected from dialkoxy magnesium, magnesium dihalide, and alkoxymagnesium halide. Among the above-mentioned magnesium compounds, dialkoxy magnesium or magnesium dihalide is preferable. Specifically, examples include dimethoxy magnesium, diethoxy magnesium, dipropoxy magnesium, dibutoxy magnesium, ethoxymethoxy magnesium, ethoxypropoxy magnesium, butoxyethoxy magnesium, magnesium dichloride, magnesium dibromide, magnesium diiodide, etc. Diethoxy magnesium and magnesium dichloride are particularly preferable.

[0022] Among the above-mentioned magnesium compounds, the dialkoxy magnesium may be obtained by reacting metallic magnesium with an alcohol in the presence of a halogen or a halogen-containing metal compound, etc.

[0023] The above-mentioned dialkoxy magnesium is preferably in granular or powder form, and its shape can be irregular or spherical.

[0024] When spherical dialkoxy magnesium is used, a polymer powder having a better particle shape (more spherical) and a narrow particle size distribution can be obtained, the handling operability of the polymer powder generated during the polymerization operation is improved, and the occurrence of blockage, etc. caused by the fine powder contained in the generated polymer powder can be suppressed.

[0025] The above spherical dialkoxymagnesium does not necessarily have to be a perfect sphere, and elliptical or potato-shaped ones can also be used.

[0026] Further, the average particle diameter (average particle diameter D50) of the above dialkoxymagnesium is preferably 1.0 to 200.0 μm, and more preferably 5.0 to 150.0 μm. Here, the average particle diameter D50 means the particle diameter at 50% in the volume integrated particle size distribution when measured using a laser light scattering diffraction method particle size analyzer. When the dialkoxymagnesium is spherical, the above average particle diameter D50 is preferably 1.0 to 100.0 μm, more preferably 5.0 to 80.0 μm, and even more preferably 10.0 to 70.0 μm.

[0027] Also, regarding the particle size distribution of dialkoxymagnesium, it is preferably one with less fine powder and coarse powder and a narrow particle size distribution. Specifically, when the dialkoxymagnesium is measured using a laser light scattering diffraction method particle size analyzer, the particles with a particle diameter of 5.0 μm or less are preferably 20% or less, and more preferably 10% or less. On the other hand, when measured using a laser light scattering diffraction method particle size analyzer, the particles with a particle diameter of 100.0 μm or more are preferably 20% or less, and more preferably 10% or less. Furthermore, when the particle size distribution is expressed as ln(D90 / D10), it is preferably 3 or less, and more preferably 2 or less. Here, D90 means the particle diameter at 90% in the volume integrated particle size distribution when measured using a laser light scattering diffraction method particle size analyzer. Also, D10 means the particle diameter at 10% in the volume integrated particle size distribution when measured using a laser light scattering diffraction method particle size analyzer.

[0028] The manufacturing method of the above spherical dialkoxymagnesium is exemplified in, for example, JP-A-62-51633, JP-A-3-74341, JP-A-4-368391, JP-A-8-73388, etc.

[0029] The magnesium compound is preferably in a solution state or a suspension state during the reaction, and the reaction can proceed favorably by being in a solution state or a suspension state.

[0030] When the magnesium compound is solid, it can be made into a magnesium compound in a solution state by dissolving it in a solvent having solubilizing ability for the magnesium compound, or a magnesium compound suspension can be made by suspending it in a solvent having no solubilizing ability for the magnesium compound. When the magnesium compound is liquid, it may be used as a magnesium compound in a solution state as it is, or may be further dissolved in a solvent having solubilizing ability for the magnesium compound and used as a magnesium compound in a solution state.

[0031] Examples of the compound capable of solubilizing the solid magnesium compound include at least one compound selected from the group consisting of alcohols, ethers, and esters. Alcohols such as ethanol, propanol, butanol, and 2-ethylhexanol are preferred, and 2-ethylhexanol is particularly preferred. On the other hand, examples of the medium having no solubilizing ability for the solid magnesium compound include one or more selected from saturated hydrocarbon solvents or unsaturated hydrocarbon solvents that do not dissolve the magnesium compound.

[0032] In the method for producing a propylene-based block copolymer according to the present invention, the tetravalent titanium halogen compound, which is a raw material component serving as a source of titanium and halogen constituting the solid catalyst component for olefin polymerization (A), is not particularly limited, but the following general formula (II) Ti(OR 2 ) t X 4-t (II) (In the formula, R 2represents an alkyl group having 1 to 4 carbon atoms, X represents a halogen atom such as a chlorine atom, a bromine atom, or an iodine atom, and t satisfies 0 ≦ s ≦ 3. It is preferable that the compound is at least one selected from the group consisting of titanium halides and alkoxytitanium halides represented by the formula ().

[0033] In the general formula (II) above, t satisfies 0 ≦ t ≦ 3. Specifically, examples of t include 0, 1, 2, or 3.

[0034] Examples of the titanium halide represented by the general formula (II) include one or more titanium tetrahalides selected from titanium tetrachloride, titanium tetrabromide, titanium tetraiodide, and the like. Examples of the alkoxytitanium halide represented by the general formula (II) include one or more selected from methoxytitanium trichloride, ethoxytitanium trichloride, propoxytitanium trichloride, n-butoxytitanium trichloride, dimethoxytitanium dichloride, diethoxytitanium dichloride, dipropoxytitanium dichloride, di-n-butoxytitanium dichloride, trimethoxytitanium chloride, triethoxytitanium chloride, tripropoxytitanium chloride, tri-n-butoxytitanium chloride, and the like. As the tetravalent titanium halogen compound, titanium tetrahalide is preferable, and titanium tetrachloride is more preferable. These titanium compounds may be used alone or in combination of two or more.

[0035] In the method for producing a propylene-based block copolymer according to the present invention, the solid catalyst component for olefin polymerization (A) contains a 1,3-diether compound as an internal electron donor compound.

[0036] In the present application documents, the 1,3-diether compound means a group of compounds having a propane as a basic skeleton and an ether group bonded to the 1,3-positions thereof (1,3-dialkoxypropane structure), and may further contain a desired substituent.

[0037] As the 1,3 - diether compound, the following general formula (III); R 3 OCH 2 CR 4 R 5 CH 2 OR 6 (III) (In the formula, R 4 and R 5 represent a hydrogen atom, a halogen atom, an alkyl group having 1 to 12 carbon atoms, a vinyl group, an alkenyl group having 3 to 12 carbon atoms, a cycloalkyl group or cycloalkenyl group having 3 to 12 carbon atoms, an aromatic hydrocarbon group having 6 to 12 carbon atoms or a halogen - substituted aromatic hydrocarbon group, an aromatic hydrocarbon group having 7 to 12 carbon atoms with a substituent, an alkylamino group having 1 to 12 carbon atoms or a dialkylamino group having 2 to 12 carbon atoms. R 4 and R 5 may be the same as or different from each other. R 4 and R 5 may be bonded to each other to form a ring. R 3 and R 6 represent an alkyl group having 1 to 12 carbon atoms, a vinyl group, an alkenyl group having 3 to 12 carbon atoms, a cycloalkyl group having 3 to 6 carbon atoms, an aromatic hydrocarbon group having 6 to 12 carbon atoms or a halogen - substituted aromatic hydrocarbon group or an aromatic hydrocarbon group having 7 to 12 carbon atoms with a substituent. R 3 and R 6 may be the same as or different from each other.) One or more compounds selected from the compounds represented by the formula can be mentioned.

[0038] As the above-mentioned 1,3-diether compound, specifically, one or more selected from 2-isopropyl-2-isobutyl-1,3-dimethoxypropane, 2,2-diisobutyl-1,3-dimethoxypropane, 2-isopropyl-2-isopentyl-1,3-dimethoxypropane, 2,2-dicyclohexyl-1,3-dimethoxypropane, 2,2-bis(cyclohexylmethyl)1,3-dimethoxypropane, 9,9-bis(methoxymethyl)fluorene, etc. may be mentioned. Among them, one or more selected from 2-isopropyl-2-isobutyl-1,3-dimethoxypropane, 2-isopropyl-2-isopentyl-1,3-dimethoxypropane, and 9,9-bis(methoxymethyl)fluorene are preferable.

[0039] In the method for producing a propylene-based block copolymer according to the present invention, since the solid catalyst component for olefin polymerization (A) contains a 1,3-diether compound as an internal electron donor compound, even when the polymerization reaction is carried out at about 45°C to 65°C, which is lower than usual, in the first polymerization step described later, the polymerization activity can be easily maintained, and a high polymerization activity can also be easily exhibited in the second polymerization step. Further, in the method for producing a propylene-based block copolymer according to the present invention, since the solid catalyst component for olefin polymerization (A) contains a 1,3-diether compound as an internal electron donor compound, in the obtained propylene-based block copolymer, even when the content ratio of the propylene / α-olefin random copolymer is as high as about 25.0 to 50.0% by mass, the melt flow rate (MFR) can be maintained high.

[0040] In the method for producing a propylene-based block copolymer according to the present invention, the solid catalyst component for olefin polymerization (A) may contain, as an internal electron donor compound, in addition to the 1,3-diether compound, one or more selected from benzoic acid esters, diesters (malonic acid diesters, maleic acid diesters, succinic acid diesters, glutaric acid esters), diol diesters, carbonic acid ethers, carbonic acid diesters, diester ethers, heteroatom-containing compounds, etc. In the method for producing a propylene-based block copolymer according to the present invention, the solid catalyst component for olefin polymerization (A) may or may not contain a phthalic acid ester as an internal electron donor compound, but it is preferably free of the phthalic acid ester.

[0041] In the method for producing a propylene-based block copolymer according to the present invention, the solid catalyst component for olefin polymerization (A) preferably contains 60 to 100% by weight, more preferably 70 to 100% by weight, and even more preferably 80 to 100% by weight of the above 1,3-diether compound based on the total content of the internal electron donor compound.

[0042] In the method for producing a propylene-based block copolymer according to the present invention, when the solid catalyst component for olefin polymerization (A) contains the 1,3-diether compound in the above ratio based on the total content of the internal electron donor compound, even when the polymerization reaction is carried out at about 45°C to 65°C, which is lower than usual, in the first polymerization step described below using the olefin polymerization catalyst containing the solid catalyst component for olefin polymerization (A), the polymerization activity can be easily maintained, and a high polymerization activity can also be easily exhibited in the second polymerization step. Further, in the method for producing a propylene-based block copolymer according to the present invention, when the solid catalyst component for olefin polymerization (A) contains the 1,3-diether compound as an internal electron donor compound in the above ratio, even when the content ratio of the propylene / α-olefin random copolymer in the obtained propylene-based block copolymer increases to about 25.0 to 50.0% by mass, it is possible to easily obtain a propylene-based block copolymer having a sufficiently high melt flow rate (MFR).

[0043] In the method for producing a propylene-based block copolymer according to the present invention, the solid catalyst component for olefin polymerization (A) may further contain polysiloxane. Polysiloxane is a polymer having a siloxane bond (-Si-O- bond) in the main chain, and is also generally referred to as silicone oil. Its viscosity at 25°C is 0.02 to 100 cm 2 / s (2 to 10,000 centistokes), more preferably 0.03 to 5 cm 2 It is a chain, partially hydrogenated, cyclic or modified polysiloxane that is liquid or viscous at room temperature and has / s (3 to 500 centistokes). In the method for producing a propylene-based block copolymer according to the present invention, when the solid catalyst component for olefin polymerization (A) further contains polysiloxane and is subjected to the polymerization of olefins, an olefin polymer excellent in stereoregularity or crystallinity can be easily produced, and furthermore, the amount of fine powder in the produced olefin polymer can be easily reduced.

[0044] In the method for producing a propylene-based block copolymer according to the present invention, the solid catalyst component for olefin polymerization (A) can be prepared, for example, by bringing dialkoxymagnesium, a tetravalent titanium halogen compound, an internal electron-donating compound, and, if necessary, polysiloxane into contact with each other in an inert organic solvent.

[0045] As the above-mentioned inert organic solvent, those that are liquid at room temperature (20°C) and have a boiling point of 50 to 150°C are preferred, and saturated hydrocarbon compounds or aromatic hydrocarbon compounds that are liquid at room temperature and have a boiling point of 50 to 150°C are more preferred.

[0046] Specific examples of the above-mentioned inert organic solvent include linear aliphatic hydrocarbon compounds such as hexane, heptane, and decane, branched aliphatic hydrocarbon compounds such as methylheptane, alicyclic hydrocarbon compounds such as cyclohexane, methylcyclohexane, and ethylcyclohexane, and aromatic hydrocarbon compounds such as toluene, xylene, and ethylbenzene, and one or more selected therefrom. Among the above-mentioned inert organic solvents, aromatic hydrocarbon compounds that are liquid at room temperature and have a boiling point of 50 to 150°C are suitable because they can easily improve the activity of the obtained solid catalyst component and can easily improve the stereoregularity of the obtained polymer.

[0047] In the method for producing a propylene-based block copolymer according to the present invention, when contacting each component to prepare the solid catalyst component for olefin polymerization (A), it can be carried out under an inert gas atmosphere.

[0048] Specifically, under an inert gas atmosphere and in a situation where moisture and the like are removed, in a container equipped with a stirrer, each component is contacted while being stirred, and then reacted at a predetermined temperature to obtain the solid catalyst component for olefin polymerization (A).

[0049] When simply contacting and stirring and mixing each component, or when dispersing or suspending and subjecting to a modification treatment, the temperature at which each component is contacted may be in a relatively low temperature range near room temperature.

[0050] When reacting after contacting each component to obtain a product, a temperature range of 40 to 130 °C is preferable. In this case, it is preferable to hold and react at the same temperature after contacting each component.

[0051] When the temperature for obtaining the above product is less than 40 °C, the reaction does not proceed sufficiently, and as a result, it becomes difficult for the obtained solid catalyst component to exhibit sufficient performance. Further, when the temperature exceeds 130 °C, the evaporation of the used solvent becomes remarkable, etc., and it becomes difficult to control the reaction.

[0052] The reaction time for obtaining the above product is preferably 1 minute or more, more preferably 10 minutes or more, and still more preferably 30 minutes or more.

[0053] Since the usage ratio of each component when preparing the solid catalyst component for olefin polymerization (A) varies depending on the preparation method, it may be appropriately determined.

[0054] When preparing the solid catalyst component for olefin polymerization (A), it is preferable to contact 0.50 to 100.00 moles of a tetravalent titanium halogen compound per 1.00 mole of the dialkoxymagnesium compound, more preferably 0.50 to 10.00 moles, and still more preferably 1.00 to 5.00 moles.

[0055] Also, when preparing the solid catalyst component for olefin polymerization, it is preferable to contact 0.01 to 10.00 moles of the internal electron donor compound per 1.00 mole of dialkoxymagnesium, more preferably 0.01 to 1.00 mole, and even more preferably 0.02 to 0.6 mole.

[0056] Furthermore, when using polysiloxane during the preparation of the solid catalyst component for olefin polymerization, it is preferable to contact 0.01 to 100.00 g of polysiloxane per 1.00 mole of dialkoxymagnesium, more preferably 0.05 to 80.00 g, and even more preferably 1.00 to 50.00 g.

[0057] Also, when preparing the solid catalyst component for olefin polymerization, the amount of the inert organic solvent used is preferably 0.001 to 500.000 moles per 1.000 mole of dialkoxymagnesium, more preferably 0.001 to 70.000 moles, and even more preferably 0.005 to 50.000 moles.

[0058] As a particularly preferred method for preparing the solid catalyst component for olefin polymerization, the following preparation methods can be mentioned.

[0059] First, dialkoxymagnesium is suspended in an inert organic solvent containing an alicyclic hydrocarbon compound having a boiling point of 50 to 150 °C to obtain a suspension. Next, a tetravalent titanium halogen compound is brought into contact with the obtained suspension for reaction treatment. Before or after bringing the tetravalent titanium halogen compound into contact with the above suspension, the internal electron donor compound is brought into contact at -20 to 130 °C. Further, if necessary, polysiloxane is brought into contact for reaction treatment. In the above preparation method, it is desirable to carry out an aging reaction at a low temperature before or after bringing the internal electron donor compound into contact.

[0060] (A) The solid catalyst component for olefin polymerization preferably contains titanium atoms in an amount of 1.0 mass% to 10.0 mass%, more preferably 1.5 mass% to 8.0 mass%, and even more preferably 1.5 mass% to 5.0 mass%.

[0061] (A) The solid catalyst component for olefin polymerization preferably contains magnesium atoms in an amount of 10.0 mass% to 70.0 mass%, more preferably 10.0 mass% to 50.0 mass%, even more preferably 15.0 mass% to 40.0 mass%, and still more preferably 15.0 mass% to 25.0 mass%.

[0062] (A) The solid catalyst component for olefin polymerization preferably contains halogen atoms in an amount of 20.0 mass% to 90.0 mass%, more preferably 30.0 mass% to 85.0 mass%, even more preferably 40.0 mass% to 80.0 mass%, and still more preferably 45.0 mass% to 80.0 mass%.

[0063] (A) The solid catalyst component for olefin polymerization preferably contains internal electron donor compounds in a total amount of 0.5 mass% to 30.0 mass%, more preferably 1.0 mass% to 25.0 mass%, and even more preferably 2.0 mass% to 20.0 mass%.

[0064] In this application document, the content rate of titanium atoms contained in the solid catalyst component for olefin polymerization means the value measured according to the method (oxidation-reduction titration) described in JIS 8311-1997 "Method for Determination of Titanium in Titanium Ore".

[0065] Also, in this application document, the content ratio of magnesium in the solid catalyst component for olefin polymerization means the value measured by the EDTA titration method in which the solid catalyst component for olefin polymerization is dissolved in a hydrochloric acid solution and titrated with an EDTA solution.

[0066] In this application document, the content ratio of the halogen atoms contained in the solid catalyst component for olefin polymerization means the value measured by the silver nitrate titration method in which, after treating the solid catalyst component with a mixed solution of sulfuric acid and pure water to obtain an aqueous solution, a predetermined amount is separated and the halogen atoms are titrated with a silver nitrate standard solution.

[0067] Also, in this application document, the content ratio of the internal electron donor compound means the value measured by the gas chromatography FID (Flame Ionization Detector) method in which, after hydrolyzing the solid catalyst, the internal electron donor is extracted using an aromatic solvent and this solution is measured.

[0068] In the method for producing a propylene-based block copolymer according to the present invention, the catalyst for olefin polymerization contains (B) an organoaluminum compound.

[0069] In the method for producing a propylene-based block copolymer according to the present invention, as the (B) organoaluminum compound constituting the catalyst for olefin polymerization, the following general formula (I) R 1 p AlQ 3-p (I) (In the formula, R 1 is an alkyl group having 1 to 6 carbon atoms, Q is a hydrogen atom or a halogen atom, p is 0 < p ≤ 3, and when there are a plurality of R 1 , each R 1 may be the same or different from each other, and when there are a plurality of Q, each Q may be the same or different from each other.) It is preferably one or more compounds represented by.

[0070] In the organoaluminum compound represented by the general formula (I), R 1 is an alkyl group having 1 to 6 carbon atoms, and specifically, a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, etc. can be mentioned.

[0071] In the organoaluminum compound represented by the general formula (I), Q represents a hydrogen atom or a halogen atom. When Q is a halogen atom, examples thereof include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.

[0072] Further, in the organoaluminum compound represented by the general formula (I), p satisfies 0 < p ≤ 3, preferably 2 to 3, more preferably 2, 2.5, or 3.

[0073] Specific examples of the organoaluminum compound represented by the general formula (I) include one or more selected from triethylaluminum, diethylaluminum chloride, triisobutylaluminum, diethylaluminum bromide, and diethylaluminum hydride. Triethylaluminum and triisobutylaluminum are preferred.

[0074] In the method for producing a propylene-based block copolymer according to the present invention, since the olefin polymerization catalyst contains a specific organoaluminum compound represented by the general formula (I), the action of the organoaluminum compound on the internal electron-donating compound constituting the solid catalyst component for olefin polymerization is improved, and it is considered that the solid catalyst component for olefin polymerization can be optimally activated. And it is considered that excellent catalytic activity can be exhibited during the polymerization treatment, and an olefin polymer excellent in stereoregularity can be produced.

[0075] In the method for producing a propylene-based block copolymer according to the present invention, the olefin polymerization catalyst preferably further contains (C) an external electron-donating compound together with (A) a solid catalyst component for olefin polymerization and (B) an organoaluminum compound.

[0076] In the method for producing a propylene-based block copolymer according to the present invention, as the (C) external electron-donating compound, for example, the following general formula (IV) R 7 r Si(NR 8 R 9 ) s (OR10 ) 4-(r+s) (IV) (In the formula, r is 0 or 1 to 2, s is 0 or 1 to 2, r + s is 0 or 1 to 4, R 7 , R 8 or R 9 is any group selected from a hydrogen atom, a linear or branched alkyl group having 1 to 12 carbon atoms, a substituted or unsubstituted cycloalkyl group, a phenyl group, an allyl group, and an aralkyl group, which may contain a hetero atom and may be the same or different from each other. R 8 and R 9 may combine to form a cyclic shape, R 7 , R 8 and R 9 may be the same or different. Further, R 10 is any group selected from an alkyl group having 1 to 4 carbon atoms, a cycloalkyl group, a phenyl group, a vinyl group, an allyl group, and an aralkyl group, which may contain a hetero atom. Examples thereof include silicon compounds represented by the following formula.)

[0077] In the silicon compound represented by the general formula (IV), R 7 is any group selected from a hydrogen atom, a linear or branched alkyl group having 1 to 12 carbon atoms, a substituted or unsubstituted cycloalkyl group, a phenyl group, an allyl group, and an aralkyl group, which may contain a hetero atom. R 7 is preferably a linear or branched alkyl group having 1 to 10 carbon atoms or a cycloalkyl group having 5 to 8 carbon atoms, and particularly preferably a linear or branched alkyl group having 1 to 8 carbon atoms or a cycloalkyl group having 5 to 8 carbon atoms.

[0078] In the silicon compound represented by the general formula (IV), R 8 or R 9 is any group selected from a hydrogen atom, a linear or branched alkyl group having 1 to 12 carbon atoms, a substituted or unsubstituted cycloalkyl group, a phenyl group, an allyl group, and an aralkyl group, which may contain a hetero atom. R 8 or R 9Examples thereof preferably include linear or branched alkyl groups having 1 to 10 carbon atoms and cycloalkyl groups having 5 to 8 carbon atoms, and particularly preferably include linear or branched alkyl groups having 1 to 8 carbon atoms and cycloalkyl groups having 5 to 8 carbon atoms. Also, R 8 and R 9 may be bonded to form a cyclic structure. In this case, the (NR 8 R 9 ) forming the cyclic structure is preferably a perhydroquinolino group or a perhydroisoquinolino group.

[0079] In the silicon compound represented by the general formula (IV), R 7 , R 8 and R 9 may be the same or different.

[0080] In the silicon compound represented by the general formula (IV), R 10 is any group selected from alkyl groups having 1 to 4 carbon atoms, cycloalkyl groups, phenyl groups, allyl groups and aralkyl groups, and may contain heteroatoms. R 10 is preferably a linear or branched alkyl group having 1 to 4 carbon atoms.

[0081] In the silicon compound represented by the general formula (IV), r is 0 or 1 to 2, and specifically, examples of r include 0, 1 or 2. In the silicon compound represented by the general formula (IV), s is 0 or 1 to 2, and specifically, examples of s include 0, 1 or 2. In the silicon compound represented by the general formula (IV), r + s is 0 or 1 to 4, and specifically, examples of r + s include 0, 1, 2, 3 or 4.

[0082] As such silicon compounds represented by the above general formula (IV), specifically, one or more organic silicon compounds selected from phenylalkoxysilane, alkylalkoxysilane, phenylalkylalkoxysilane, cycloalkylalkoxysilane, cycloalkylalkylalkoxysilane, (alkylamino)alkoxysilane, alkyl(alkylamino)alkoxysilane, alkyl(alkylamino)silane, alkylaminosilane, etc. can be mentioned.

[0083] As the silicon compound where s is 0 in the above general formula (IV), particularly preferably, one or more organic silicon compounds selected from di-n-propyldimethoxysilane, diisopropyldimethoxysilane, di-n-butyldimethoxysilane, diisobutyldimethoxysilane, di-t-butyldimethoxysilane, t-butylmethyldimethoxysilane, t-butylethyldimethoxysilane, di-n-butyldiethoxysilane, t-butyltrimethoxysilane, t-butyltriethoxysilane, dicyclohexyldimethoxysilane, dicyclohexyldiethoxysilane, cyclohexylmethyldimethoxysilane, cyclohexylmethyldiethoxysilane, cyclohexylethyldimethoxysilane, cyclohexylethyldiethoxysilane, dicyclopentyldimethoxysilane, dicyclopentyldiethoxysilane, cyclopentylmethyldimethoxysilane, cyclopentylmethyldiethoxysilane, cyclopentylethyldiethoxysilane, cyclohexylcyclopentyldimethoxysilane, cyclohexylcyclopentyldiethoxysilane, 3-methylcyclohexylcyclopentyldimethoxysilane, 4-methylcyclohexylcyclopentyldimethoxysilane, 3,5-dimethylcyclohexylcyclopentyldimethoxysilane can be mentioned.

[0084] Examples of the silicon compound in which s is 1 or 2 in the general formula (IV) above include one or more organosilicon compounds selected from di(alkylamino)dialkoxysilanes, (alkylamino)(cycloalkylamino)dialkoxysilanes, (alkylamino)(alkyl)dialkoxysilanes, di(cycloalkylamino)dialkoxysilanes, vinyl(alkylamino)dialkoxysilanes, allyl(alkylamino)dialkoxysilanes, (alkoxyamino)trialkoxysilanes, (alkylamino)trialkoxysilanes, (cycloalkylamino)trialkoxysilanes, etc. Particularly preferred are ethyl(t-butylamino)dimethoxysilane, cyclohexyl(cyclohexylamino)dimethoxysilane, ethyl(t-butylamino)dimethoxysilane, bis(cyclohexylamino)dimethoxysilane, bis(perhydroisoquinolino)dimethoxysilane, bis(perhydroquinolino)dimethoxysilane, ethyl(isoquinolino)dimethoxysilane, diethylaminotrimethoxysilane, diethylaminotriethoxysilane, etc. Among them, one or more organosilicon compounds selected from bis(perhydroisoquinolino)dimethoxysilane, diethylaminotrimethoxysilane, or diethylaminotriethoxysilane are used.

[0085] In addition, the silicon compounds represented by the general formula (IV) above may be used in combination of two or more.

[0086] In the method for producing a propylene-based block copolymer according to the present invention, the olefin polymerization catalyst contains (A) a solid catalyst component for olefin polymerization, (B) an organoaluminum compound, and optionally (C) an external electron donor compound, that is, these contact substances. The olefin polymerization catalyst described above may be prepared by contacting (A) a solid catalyst component for olefin polymerization, (B) an organoaluminum compound, and optionally (C) an external electron donor compound in the absence of olefins, or may be prepared by contacting them in the presence of olefins (in the polymerization system) as described below.

[0087] In the method for producing a propylene-based block copolymer according to the present invention, the content ratios of the respective components constituting the olefin polymerization catalyst are arbitrary as long as they do not affect the effects of the present invention and are not particularly limited. However, usually, per mole of titanium atom in the above-mentioned (A) solid catalyst component for olefin polymerization, the above-mentioned (B) organoaluminum compound preferably contains 1 to 2000 moles, and more preferably contains 50 to 1000 moles. Further, the above-mentioned olefin polymerization catalyst preferably contains 0.002 to 10.000 moles, more preferably 0.010 to 2.000 moles, and even more preferably 0.010 to 0.500 moles of the above-mentioned (C) external electron donor compound per mole of the above-mentioned (B) organoaluminum compound.

[0088] The above-mentioned olefin polymerization catalyst can be produced by bringing the above-mentioned (A) solid catalyst component for olefin polymerization, (B) organoaluminum compound, and, if necessary, (C) external electron donor compound into contact with each other. That is, it can be produced by bringing the above-mentioned (A) solid catalyst component for olefin polymerization and (B) organoaluminum compound into contact with each other in the presence or absence of the above-mentioned (C) external electron donor compound.

[0089] When producing the above-mentioned olefin polymerization catalyst, when the contact between the (A) solid catalyst component for olefin polymerization and the (B) organoaluminum compound is carried out in the absence of the (C) external electron donor compound, after bringing the (A) solid catalyst component for olefin polymerization and the (B) organoaluminum compound into contact with each other, it is preferable to further bring the contact-treated product thus obtained into contact with the (C) external electron donor compound.

[0090] When producing the above-mentioned catalyst for olefin polymerization, the contact amounts of the above-mentioned solid catalyst component (A) for olefin polymerization and the organoaluminum compound (B), and the contact amount of the external electron donor compound (C) used as necessary may be appropriately determined according to the composition of the catalyst for olefin polymerization to be obtained.

[0091] When preparing the above-mentioned catalyst for olefin polymerization, the inert gas concentration in the atmosphere is preferably 0.0 to 1.0 mol / L, more preferably 0.0 to 0.5 mol / L, and even more preferably 0.0 to 0.1 mol / L.

[0092] Examples of the inert gas include one or more selected from nitrogen gas, helium gas, neon gas, argon gas, and the like.

[0093] The above-mentioned catalyst for olefin polymerization may be produced in the presence of the olefins to be polymerized, or may be produced in the absence of the olefins to be polymerized.

[0094] When producing the above-mentioned catalyst for olefin polymerization, the temperature at which each component is brought into contact is preferably 40°C or lower, more preferably 0°C to 40°C, even more preferably 10°C to 40°C, and particularly preferably 10°C to 20°C.

[0095] When producing the above-mentioned catalyst for olefin polymerization, the treatment time when each component is subjected to a contact treatment is preferably 10 seconds to 60 minutes, more preferably 30 seconds to 30 minutes, even more preferably 1 minute to 30 minutes, and particularly preferably 1 minute to 10 minutes.

[0096] When producing the above-mentioned catalyst for olefin polymerization, when the solid catalyst component (A) for olefin polymerization and the organoaluminum compound (B), and further, if necessary, the external electron donor compound (C) are brought into contact, the reaction starts instantaneously, and the target catalyst for olefin polymerization can be formed.

[0097] In the method for producing a propylene-based block copolymer according to the present invention, by using a catalyst for olefin polymerization having a specific solid catalyst component (A) for olefin polymerization and an organoaluminum compound (B), even when the polymerization reaction is carried out at a relatively low temperature in the first polymerization step described later, a sufficiently high polymerization activity can be easily exhibited, and a high polymerization activity can also be easily exhibited in the second polymerization step, and a propylene-based block copolymer having a melt flow rate sufficiently high in practical use and a high content ratio of the propylene / α-olefin copolymer component can be easily produced.

[0098] In the method for producing a propylene-based block copolymer according to the present invention, the above catalyst for olefin polymerization is used. After performing a first polymerization step of polymerizing olefins containing 95 to 100% by mass of propylene under a temperature condition of 45°C to 65°C to obtain a propylene-based polymer. Furthermore, under a temperature condition of 50°C to 90°C, a second polymerization step is performed in which olefins containing 5% by mass or more and less than 95% by mass of propylene and an α-olefin excluding propylene are copolymerized in the presence of the propylene-based polymer to obtain a propylene / α-olefin copolymer.

[0099] In the method for producing a propylene-based block copolymer according to the present invention, in the first polymerization step, it is preferable to use olefins containing 95 to 100% by mass of propylene, and more preferably to use olefins containing 97 to 100% by mass of propylene, and even more preferably to use olefins containing 99 to 100% by mass of propylene.

[0100] In the method for producing a propylene-based block copolymer according to the present invention, the first polymerization step is carried out under a temperature condition of 45°C to 65°C, preferably under a temperature condition of 50 to 65°C, and more preferably under a temperature condition of 55 to 60°C.

[0101] In the method for producing a propylene-based block copolymer according to the present invention, by performing the first polymerization step under the above temperature conditions, while suppressing an excessive polymerization reaction in the first polymerization step, since the specific olefin polymerization catalyst described above is used, a propylene-based polymer as an intermediate product can be easily obtained while easily exhibiting high polymerization activity.

[0102] In the method for producing a propylene-based block copolymer according to the present invention, as the second polymerization step, in the presence of the propylene-based polymer obtained as an intermediate product, olefins containing 5% by mass or more and less than 95% by mass of propylene and an α-olefin other than propylene are copolymerized to obtain a propylene / α-olefin copolymer.

[0103] In the method for producing a propylene-based block copolymer according to the present invention, the α-olefin other than propylene used in the second polymerization step is not particularly limited as long as it is one or more selected from α-olefins other than propylene, and examples thereof include one or more selected from ethylene, 1-butene, 1-pentene, 4-methyl-1-pentene, vinylcyclohexane, etc., and ethylene or 1-butene is preferred.

[0104] In the method for producing a propylene-based block copolymer according to the present invention, in the second polymerization step, it is preferable to use olefins containing 5% by mass or more and less than 95% by mass of propylene and an α-olefin excluding propylene, and it is more preferable to use olefins containing 10% by mass to 90% by mass of propylene and 10% by mass to 90% by mass of an α-olefin excluding propylene, and it is even more preferable to use olefins containing 20% by mass to 80% by mass of propylene and 20% by mass to 80% by mass of an α-olefin excluding propylene.

[0105] In the method for producing a propylene-based block copolymer according to the present invention, the second polymerization step is carried out under a temperature condition of 50°C to 90°C, preferably carried out under a temperature condition of 55°C to 90°C, more preferably carried out under a temperature condition of 65°C to 90°C, even more preferably carried out under a temperature condition of 70°C to 85°C, and particularly preferably carried out under a temperature condition of 70°C to 80°C.

[0106] In the method for producing a propylene-based block copolymer according to the present invention, by carrying out a polymerization reaction under the above temperature conditions in the second polymerization step using the above-mentioned specific olefin polymerization catalyst, excellent polymerization activity can be easily exhibited in the second polymerization step, and a propylene-based block copolymer with a high content ratio of propylene / α-olefin copolymer can be easily produced.

[0107] In the method for producing a propylene-based block copolymer according to the present invention, olefin monomers such as propylene can be used in either gaseous or liquid state, and the treatments in the above first polymerization step and second polymerization step can be carried out in the presence or absence of an organic solvent.

[0108] Specifically, in the first polymerization step, by adjusting the polymerization temperature and polymerization time, polymerization of a monomer corresponding to 50 to 70% by mass of the entire propylene-based block copolymer to be obtained is carried out. Then, in the second polymerization step, propylene and other α-olefins (such as ethylene) are introduced, and a rubber part such as ethylene-propylene rubber (EPR) or ethylene-propylene-1-butene terpolymer is polymerized while adjusting the reaction conditions so that the ratio becomes 25.0 to 50.0% by mass of the entire propylene-based block copolymer to be obtained.

[0109] The polymerization reaction in the above second polymerization step is generally preferably carried out by a gas-phase polymerization reaction in order to suppress elution of a rubber part such as EPR from polypropylene particles. Also, the polymerization reactions in the above first polymerization step and second polymerization step may be carried out by either a continuous polymerization method or a batch polymerization method. Furthermore, the polymerization reaction may be carried out in one stage or multiple stages in either the first polymerization step or the second polymerization step. When each step is carried out in multiple stages, they can be carried out under the same conditions or different conditions respectively.

[0110] In the method for producing a propylene-based block copolymer according to the present invention, the polymerization of olefins in the first polymerization step and the second polymerization step can be carried out by heating and pressurizing in a reactor (polymerization tank) such as an autoclave in the presence of a catalyst for olefin polymerization.

[0111] For example, after performing a first polymerization step of polymerizing a monomer containing only propylene as olefins in the first polymerization tank to obtain a propylene-based polymer, in the presence of the obtained propylene-based polymer, in a second polymerization tank or multiple stages (multi-stage polymerization tanks) above, a second polymerization step of copolymerizing propylene and an α-olefin excluding propylene (such as ethylene) to obtain a propylene / α-olefin random copolymer is carried out, whereby the target propylene-based block copolymer can be produced.

[0112] The polymerization pressure in the above first polymerization step and second polymerization step is preferably 10 MPa or less, and more preferably 5 MPa or less. Furthermore, the polymerization time (residence time of the reaction raw materials) is suitably such that the total of the polymerization times in the first polymerization step and the second polymerization step is 1 minute to 5 hours.

[0113] In the method for producing a propylene-based block copolymer according to the present invention, when polymerizing olefins using a catalyst for olefin polymerization (also referred to as main polymerization), in order to further improve the catalyst activity, stereoregularity, and particle properties of the resulting polymer, it is preferable to perform prepolymerization prior to the main polymerization. When performing prepolymerization, the same olefins as in the main polymerization or monomers such as styrene can be used.

[0114] When carrying out prepolymerization, the contacting order of each component constituting the olefin polymerization catalyst and the monomer (olefins) is arbitrary. Preferably, in a prepolymerization system set in an inert gas atmosphere or an olefin gas atmosphere, first an organoaluminum compound is charged, and then the above-mentioned solid catalyst component for olefin polymerization is charged and contacted. After that, it is preferable to contact olefins such as propylene alone or a mixture of propylene and an α-olefin excluding propylene. In the above prepolymerization, when further charging (C) an external electron donor compound into the prepolymerization system, in the prepolymerization system set in an inert gas atmosphere or an olefin gas atmosphere, first (B) an organoaluminum compound is charged, then (C) the external electron donor compound is charged and contacted, and further the above-mentioned (A) solid catalyst component for olefin polymerization is contacted. After that, it is preferable to contact olefins such as propylene alone or a mixture of propylene and an α-olefin excluding propylene.

[0115] Examples of the propylene-based block copolymer obtained by the production method according to the present invention include the propylene-based block copolymer according to the present invention described below.

[0116] Next, the propylene-based block copolymer obtained by the production method according to the present invention will be described.

[0117] As the propylene-based block copolymer obtained by the production method according to the present invention, those having a melt flow rate (MFR) of 10 to 200 g / 10 minutes are preferable, those having a melt flow rate of 15 to 150 g / 10 minutes are more preferable, and those having a melt flow rate of 20 to 100 g / 10 minutes are even more preferable.

[0118] In the present application documents, the melt flow rate (MFR) indicating the melt fluidity of the polymer means the value measured according to ASTM D 1238 and JIS K 7210.

[0119] In the method for producing a propylene-based block copolymer according to the present invention, as the propylene-based block copolymer to be obtained, those having a propylene / α-olefin copolymer content of 25.0 to 50.0% by mass are preferred, more preferably 30.0 to 45.0% by mass, and even more preferably 35.0 to 40.0% by mass.

[0120] In the present application documents, the content ratio of the propylene / α-olefin copolymer in the propylene-based block copolymer means a value calculated by charging 5.0 g of the propylene-based block copolymer and 250 ml of p-xylene into a flask equipped with a stirrer, setting the external temperature to be equal to or higher than the boiling point of xylene (about 150 °C) to maintain the temperature of p-xylene inside the flask below the boiling point (137 to 138 °C), dissolving the polymer over 2 hours, then cooling the liquid temperature to 23 °C over 1 hour, filtering and separating the insoluble component and the soluble component, collecting the solution of the soluble component, distilling off p-xylene by heating under reduced pressure, determining the weight of the obtained residue, and calculating the relative ratio (% by mass) with respect to the produced polymer (propylene-based block copolymer).

[0121] In the method for producing a propylene-based block copolymer according to the present invention, as the propylene-based block copolymer to be obtained, the content ratio of the propylene-based polymer is preferably 50.0 to 75.0% by mass, more preferably 55.0 to 70.0% by mass, and even more preferably 60.0 to 65.0% by mass.

[0122] In the present application documents, the content ratio of the propylene-based polymer in the propylene-based block copolymer means a value obtained by subtracting the propylene / α-olefin copolymer content (% by mass) determined by the above-described method and the ethylene content (% by mass) in the xylene-insoluble matter from the total weight (% by mass) of the produced polymer (propylene-based block copolymer) with the total weight of the produced polymer (propylene-based block copolymer) being 100 (% by mass). The ethylene content in the xylene-insoluble matter means a value calculated based on a calibration curve prepared from a plurality of samples with known contents, from the absorbance measured using a Fourier transform infrared spectrometer (FT-IR, Thermo Nicolet, Avatar) and the film thickness, after sampling a small amount of the xylene-insoluble matter obtained when measuring the above-mentioned propylene / α-olefin copolymer content and forming it into a film by hot pressing. Measurement wavelength: 720 cm -1 and 1150 cm -1 Film thickness: 0.1 - 0.2 mm

[0123] According to the present invention, it is excellent in polymerization activity in the first polymerization step of performing a homopolymerization reaction of propylene or a copolymerization reaction of propylene and a small amount of α-olefin (excluding propylene), and in the presence of the propylene-based polymer obtained in the first polymerization step, it is excellent in polymerization activity in the second polymerization step of performing a copolymerization reaction of propylene and α-olefin (excluding propylene), and it is possible to provide a method for easily producing a propylene-based block copolymer having a melt flow rate sufficiently high in practical use and a high content ratio of the propylene / α-olefin copolymer component.

Examples

[0124] Next, the present invention will be described more specifically with reference to Examples and Comparative Examples, but the present invention is not limited by the following examples.

[0125] (Examples 1 to 3, Comparative Examples 1 to 2) (1) Preparation of solid catalyst component for olefin polymerization A flask with an internal volume of 500 mL replaced with nitrogen gas and equipped with a stirring device was charged with 10 g (87.4 mmol) of diethoxymagnesium, 80 mL of toluene, 20 mL of titanium tetrachloride, and 12.0 mmol (2.6 g) of 2-isopropyl-2-isopentyl-1,3-dimethoxypropane, and they were brought into contact with each other at a temperature of 100 °C for 120 minutes to react. After completion of the reaction, the contact product was washed 4 times with 60 mL of toluene at 100 °C. A toluene solution of titanium tetrachloride with a volume ratio of titanium tetrachloride to toluene (titanium tetrachloride / toluene volume ratio) of 0.28 was newly added, and the mixture was stirred at 100 °C for 15 minutes to react, and after the reaction, the supernatant was withdrawn. After performing this operation one more time, the solid catalyst component for olefin polymerization was obtained by washing 6 times with 75 mL of n-heptane at 40 °C.

[0126] (2) Formation of a catalyst for olefin polymerization Into an autoclave with a stirrer having an internal volume of 2.0 L completely replaced with nitrogen gas, 2.42 mmol of triethylaluminum and 0.0030 mmol of the solid catalyst component for olefin polymerization obtained in the above (1) in terms of titanium atoms were charged to prepare a catalyst for olefin polymerization.

[0127] (3) Production of an ethylene-propylene block copolymer After forming the catalyst for olefin polymerization in (2), 3.5 L of hydrogen gas and 1.2 L of liquefied propylene were charged into the autoclave with a stirrer in which the catalyst for olefin polymerization was formed, and prepolymerization was carried out at 20 °C for 5 minutes, and then the temperature was raised, and a homopropylene (homo stage) polymerization reaction was carried out as the first polymerization step at the polymerization temperature and polymerization time shown in Table 1, respectively.

[0128] After the above homopolypropylene (homo stage) polymerization reaction, propylene, ethylene, and hydrogen were supplied into the autoclave with a stirrer where the above homopolypropylene (homo stage) polymerization reaction was carried out at a pressure of 1.2 MPa at rates of 2.3 L / min, 1.7 L / min, and 0.086 L / min, respectively, and a copolymerization reaction was carried out at the polymerization temperature and polymerization time shown in Table 1 to produce a propylene / ethylene copolymer, thereby obtaining each ethylene-propylene block copolymer.

[0129] In the obtained ethylene-propylene block copolymer, the propylene polymerization activity (homo stage polymerization activity, g / g-catalyst), ethylene-propylene block copolymerization (ICP) activity (g / g-catalyst), total polymerization activity (g / g-catalyst), block ratio of the obtained block copolymer (polymerization ratio of the copolymerized part, mass%), melt flow rate (MFR) of the obtained block copolymer, ethylene-propylene copolymer (EPR) content ratio in the obtained block copolymer (mass%), and ethylene content ratio in the ethylene-propylene copolymer (EPR) were measured by the following methods, respectively. The results are shown in Table 1.

[0130] <Propylene polymerization activity> The homo stage polymerization activity in the copolymerization reaction was calculated by the following formula. Homo stage polymerization activity (g / g-catalyst) = (G(g) - F(g)) / mass of solid catalyst component (g) Here, G(g) is the mass of the autoclave (g) after removing unreacted monomers after the completion of the homo PP polymerization reaction, and F(g) is the mass of the autoclave (g).

[0131] <Ethylene-propylene block copolymerization (ICP) activity (g / g-catalyst)> The copolymerization (ICP) activity when forming the ethylene-propylene block copolymer was calculated by the following formula. Copolymerization (ICP) activity (g / g-catalyst) = ((I(g) - G(g)) / mass of solid catalyst component contained in the catalyst for olefin polymerization (g)) Here, I(g) is the autoclave mass (g) after the copolymerization reaction is completed, and G(g) is the autoclave mass (g) after the unreacted monomer is removed after the homopolymerization reaction of homopolypropylene is completed.

[0132] <Total polymerization activity (g / g-catalyst)> The total polymerization activity (g / g-catalyst) during the production of the ethylene-propylene block copolymer was calculated by the following formula. Total polymerization activity (g / g-catalyst) = homopolymerization stage polymerization activity (g / g-catalyst) + copolymerization (ICP) activity (g / g-catalyst)

[0133] <Block ratio (mass%)> The block ratio of the obtained ethylene-propylene block copolymer was calculated by the following formula. Block ratio (mass%) = {(I(g) - G(g)) / (I(g) - F(g))} × 100 Here, I is the autoclave mass (g) after the copolymerization reaction is completed, G is the autoclave mass (g) after the unreacted monomer is removed after the homopolymerization of homopolypropylene is completed, and F is the autoclave mass (g).

[0134] <Melt flow rate (MFR)> The melt flow rate (MFR) indicating the melt fluidity of the obtained ethylene-propylene block copolymer was measured according to ASTM D 1238 and JIS K 7210.

[0135] <Ethylene-propylene copolymer (EPR) content (xylene-soluble content in the ICP polymer)> 5.0 g of the copolymer (ethylene-propylene block copolymer) and 250 mL of p-xylene were charged into a flask equipped with a stirring device. Then, the external temperature was set to about 150°C, and stirring was continued for 2 hours while maintaining the reflux of p-xylene (boiling point 137 - 138°C) in the flask to dissolve the above polymer. Thereafter, the solution was allowed to stand for 1 hour and cooled until the liquid temperature reached 23°C, and the xylene-soluble component (EPR) and the xylene-insoluble component (XI) were separated by filtration. The soluble components were sampled for each solution, p-xylene was distilled off by heating under reduced pressure, the weight of the obtained residue was determined, and the relative ratio (mass %) with respect to the produced polymer (ethylene-propylene block copolymer) was calculated to obtain the EPR content (the amount of xylene-soluble components in the ethylene-propylene block copolymer).

[0136] <Ethylene content in the EPR component> A small amount of the xylene-soluble component (EPR) separated at the EPR content of the copolymer was sampled, formed into a film by hot pressing, and then the ethylene content in the xylene-soluble component (XS) of ICP was calculated based on the calibration curve prepared from a plurality of samples with known contents from the absorbance measured using a Fourier transform infrared spectrometer (FT-IR) (manufactured by Thermonicolet, Avatar) and the film thickness. Measurement wavelength: 720 cm -1 and 1150 cm -1 Film thickness: 0.1 - 0.2 mm

[0137] <Ethylene content in the xylene-insoluble component (XI)> A small amount of the xylene-insoluble component (XI) separated to determine the EPR content ratio of the copolymer was sampled, formed into a film by hot pressing, and then the ethylene content in the xylene-insoluble component (XI) of ICP was calculated in the same manner as the ethylene content in the xylene-soluble component (XS) of the above ICP.

[0138] (Example 4, Comparative Example 3) (1) Preparation of solid catalyst component for olefin polymerization A flask with an internal volume of 500 mL replaced with nitrogen gas and equipped with a stirring device was charged with 10 g (87.4 mmol) of diethoxymagnesium, 55 mL of toluene, 15 mL of titanium tetrachloride, and 10.0 mmol (2.2 g) of 2-isopropyl-2-isopentyl-1,3-dimethoxypropane, and they were brought into contact with each other and reacted at a temperature of 100 °C for 180 minutes. After the reaction was completed, the contact product was washed 5 times with 55 mL of toluene at 90 °C. A toluene solution of titanium tetrachloride with a volume ratio of titanium tetrachloride to toluene (titanium tetrachloride / toluene volume ratio) of 0.33 was newly added, and the mixture was stirred and reacted at 100 °C for 15 minutes. After the reaction, the supernatant was withdrawn. This operation was further repeated 3 times, and then the solid catalyst component for olefin polymerization was obtained by washing 6 times with 75 mL of n-heptane at 40 °C.

[0139] (2) Formation of Catalyst for Olefin Polymerization Into an autoclave with an internal volume of 2.0 L equipped with a stirrer completely replaced with nitrogen gas, 2.42 mmol of triethylaluminum and 0.030 mmol of the solid catalyst component for olefin polymerization obtained in the above (1) in terms of titanium atoms were charged to prepare a catalyst for olefin polymerization (ethylene-propylene copolymerization catalyst).

[0140] (3) Production of Ethylene-Propylene Block Copolymer After forming the catalyst for olefin polymerization in (2), 3.5 L of hydrogen gas and 1.2 L of liquefied propylene were charged into the autoclave with a stirrer in which the catalyst for olefin polymerization was formed, and prepolymerization was carried out at 20 °C for 5 minutes, and then the temperature was raised. The homopropylene (homo stage) polymerization reaction was carried out as the first polymerization step at the polymerization temperature and polymerization time shown in Table 1, respectively.

[0141] After the above homopropylene (homo stage) polymerization reaction, propylene, ethylene, and hydrogen were supplied into the autoclave equipped with a stirrer in which the above homopropylene (homo stage) polymerization reaction was carried out under a pressure of 1.2 MPa at rates of 2.3 L / min, 1.7 L / min, and 0.086 L / min, respectively, and a copolymerization reaction was carried out at the polymerization temperature and polymerization time shown in Table 1, respectively, to produce an ethylene-propylene copolymer, thereby obtaining each ethylene-propylene block copolymer.

[0142] In the obtained ethylene-propylene block copolymer, by the same method as in Example 1, propylene polymerization activity (homo stage polymerization activity, g / g-catalyst), ethylene-propylene block copolymerization (ICP) activity (g / g-catalyst), total polymerization activity (g / g-catalyst), block ratio of the obtained block copolymer (polymerization ratio of the copolymerized part, mass%), melt flow rate (MFR) of the obtained block copolymer, ethylene-propylene copolymer (EPR) content ratio (mass%) in the obtained block copolymer, and ethylene content ratio (mass%) in the ethylene-propylene copolymer (EPR) were measured, respectively. The results are shown in Table 1.

[0143] (Comparative Example 4, Comparative Example 5) (1) Preparation of solid catalyst component for olefin polymerization 10 g (87.4 mmol) of diethoxymagnesium, 90 mL of toluene, 30 mL of titanium tetrachloride, and 15.8 mmol (4.4 g) of dibutyl phthalate were added to a 500 mL flask equipped with a stirring device and substituted with nitrogen gas, and they were brought into contact with each other and reacted at a temperature of 90 °C for 180 minutes. After the reaction was completed, the contact product was washed 4 times with 75 mL of toluene at 90 °C. A toluene solution of titanium tetrachloride with a volume ratio of titanium tetrachloride to toluene (titanium tetrachloride / toluene volume ratio) of 0.74 was newly added, and the mixture was stirred and reacted at 110 °C for 60 minutes. After the reaction, the supernatant was withdrawn. Thereafter, a solid catalyst component for olefin polymerization was obtained by washing 6 times with 75 mL of n-heptane at 40 °C.

[0144] (2) Formation of catalyst for olefin polymerization Into an autoclave with a stirrer having an internal volume of 2.0 liters that was completely replaced with nitrogen gas, 2.42 mmol of triethylaluminum, 0.24 mmol of cyclohexylmethyldimethoxysilane, and 0.034 mmol of the solid catalyst component for olefin polymerization obtained in the above (1) in terms of titanium atoms were charged to prepare a catalyst for olefin polymerization (ethylene-propylene copolymerization catalyst).

[0145] (3) Production of ethylene-propylene block copolymer After forming the catalyst for olefin polymerization in (2), 3.5 liters of hydrogen gas and 1.2 liters of liquefied propylene were charged into the autoclave with a stirrer in which the catalyst for olefin polymerization was formed, and prepolymerization was carried out at 20 °C for 5 minutes, followed by heating the temperature. The homopropylene (homo stage) polymerization reaction was carried out as the first polymerization step at the polymerization temperature and polymerization time shown in Table 1, respectively.

[0146] After the above homopropylene (homo stage) polymerization reaction, propylene, ethylene, and hydrogen were supplied into the autoclave with a stirrer in which the above homopropylene (homo stage) polymerization reaction was carried out at a pressure of 1.2 MPa at rates of 2.3 L / min, 1.7 L / min, and 0.086 L / min, respectively, and a copolymerization reaction was carried out at the polymerization temperature and polymerization time shown in Table 1, respectively, to produce an ethylene-propylene copolymer, thereby obtaining each ethylene-propylene block copolymer.

[0147] In the obtained ethylene-propylene block copolymer, in the same manner as in Example 1, the propylene polymerization activity (homo stage polymerization activity, g / g-catalyst), ethylene-propylene block copolymerization (ICP) activity (g / g-catalyst), total polymerization activity (g / g-catalyst), block ratio of the obtained block copolymer (polymerization ratio of the copolymerized part, mass%), melt flow rate (MFR) of the obtained block copolymer, ethylene-propylene copolymer (EPR) content ratio (mass%) in the obtained block copolymer, and ethylene content ratio (mass%) in the ethylene-propylene copolymer (EPR) were measured, respectively. The results are shown in Table 1.

[0148]

Table 1

[0149] From Table 1, in Examples 1 to 3, a catalyst for olefin polymerization having a specific solid catalyst component for olefin polymerization containing a 1,3-diether compound as an internal electron donor compound and an organoaluminum compound is used, and in the first polymerization step (homo stage), the polymerization reaction is carried out at a relatively low temperature within the range of 45°C to 65°C. Therefore, high polymerization activity can be easily exhibited in the first polymerization step (homo stage) and the second polymerization step (copolymerization stage), and it can be seen that an ethylene-propylene block copolymer having a melt flow rate (MFR) sufficiently high in practical use, a high block rate, and a high EPR content can be easily produced.

[0150] On the other hand, from Table 1, in Comparative Examples 1 to 2, since the catalyst for olefin polymerization is subjected to the polymerization reaction at a temperature exceeding 65°C in the first polymerization step (homo stage), the polymerization activity in the second polymerization step (copolymerization stage) becomes low, and it can be seen that only an ethylene-propylene block copolymer having a low block rate and a low EPR content can be obtained.

[0151] Also, from Table 1, in Example 4 as well, a catalyst for olefin polymerization having a specific solid catalyst component for olefin polymerization containing a 1,3-diether compound as an internal electron donor compound and an organoaluminum compound is used, and in the first polymerization step (homo stage), the polymerization reaction is carried out at a relatively low temperature within the range of 45°C to 65°C. Therefore, high polymerization activity can be easily exhibited in the first polymerization step (homo stage) and the second polymerization step (copolymerization stage), and it can be seen that an ethylene-propylene block copolymer having a melt flow rate (MFR) sufficiently high in practical use, a high block rate, and a high EPR content can be easily produced.

[0152] On the one hand, from Table 1, in Comparative Example 3, since the olefin polymerization catalyst is subjected to a polymerization reaction at a temperature exceeding 65°C in the first polymerization step (homo step), the polymerization activity in the second polymerization step (copolymerization step) is low, and it can be seen that only an ethylene-propylene block copolymer with a low block ratio and a low EPR content can be obtained.

[0153] Furthermore, from Table 1, in Comparative Examples 4 to 5, since an olefin polymerization catalyst having a solid catalyst component for olefin polymerization that does not contain a 1,3-diether compound as an internal electron donor compound and an organoaluminum compound is used, it is inferior in polymerization activity in the first polymerization step (homo step) and the second polymerization step (copolymerization step), and it can be seen that only an ethylene-propylene block copolymer with a low melt flow rate (MFR) can be obtained.

Industrial Applicability

[0154] According to the present invention, it is excellent in polymerization activity in the first polymerization step of performing a homopolymerization reaction of propylene or a copolymerization reaction of propylene and a small amount of α-olefin (excluding propylene), and in the presence of the propylene-based polymer obtained in the first polymerization step, it is excellent in polymerization activity in the second polymerization step of performing a copolymerization reaction of propylene and α-olefin (excluding propylene), and it is possible to provide a method for easily producing a propylene-based block copolymer having a high melt flow rate and a high content ratio of the propylene / α-olefin copolymer component.

Claims

1. (A) a solid catalyst component for olefin polymerization containing titanium, magnesium, a halogen, and a 1,3-diether compound which is an internal electron donor compound; (B) an organoaluminum compound; and using a catalyst for olefin polymerization containing the same, after performing a first polymerization step of polymerizing olefins containing 95 to 100% by mass of propylene under a temperature condition of 45°C to 65°C to obtain a propylene-based polymer, further, under a temperature condition of 50°C to 90°C, copolymerizing olefins containing 5% by mass or more and less than 95% by mass of propylene and an α-olefin excluding propylene in the presence of the propylene-based polymer to obtain a propylene / α-olefin copolymer; A method for producing a propylene-based block copolymer, characterized by the above.

2. The method for producing a propylene-based block copolymer according to Claim 1, wherein the (B) organoaluminum compound is one or more compounds represented by the following general formula (I): R １ ｐ AlQ ３－ｐ (I) (wherein, R １ is an alkyl group having 1 to 6 carbon atoms, Q is a hydrogen atom or a halogen atom, p satisfies 0 < p ≦ 3, and when there are a plurality of R １ , each R １ may be the same as or different from each other, and when there are a plurality of Q, each Q may be the same as or different from each other.)

3. The method for producing a propylene-based block copolymer according to Claim 1, wherein the catalyst for olefin polymerization further contains (C) an external electron donor compound.

4. The method for producing a propylene-based block copolymer according to any one of Claims 1 to 3, wherein in the obtained propylene-based block copolymer, the content ratio of the propylene / α-olefin part is 25.0 to 50.0% by mass.

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