Method for drying particles containing polyolefins

Abstract

The present invention relates to a drying method of particles containing polyolefin. The present invention aims at reducing harmful volatile organic compounds. A drying method of particles containing polyolefin, wherein the drying method of particles containing polyolefin comprises a drying step of supplying the particles containing polyolefin into a drying vessel and supplying a drying gas into the drying vessel to thereby dry the particles containing polyolefin in the drying vessel, and wherein a value calculated from the following formula (a) is 441 or more and 600 or less in the drying step. Formula (a): 38.0 x [η]CXIS [dL / g] - 0.500 x CXIS content [mass %] + 1.20 x particle temperature in drying [K] + 3.29 x drying time [hour].

Description

Technical Field

[0001] This invention relates to a drying method for particles containing polyolefins. Background Technology

[0002] In methods for manufacturing polyolefin-containing particles, a step of drying (degassing) the polyolefin-containing particles is typically included. Specifically, for example, a method for manufacturing a polyolefin polymer is known that includes a step of degassing the polyolefin particles by contacting them with nitrogen gas in a degassing container (see Patent Document 1).

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent Document 1: Japanese Patent Application Publication No. 2015-537102 Summary of the Invention

[0006] The problem that the invention aims to solve

[0007] However, it is difficult to say that the removal of harmful volatile organic compounds in the manufactured polyolefins is sufficient through the existing drying (degassing) process.

[0008] means for solving problems

[0009] In order to solve the above problems, the inventors conducted in-depth research and found that by drying the particles containing polyolefins in a manner that meets the specified requirements, the above problems can be solved, thus completing the present invention.

[0010] That is, the present invention provides the following [1] to

[10] .

[0011] [1] A method for drying particles containing polyolefins, wherein the method comprises the following drying steps: feeding the particles containing polyolefins into a drying container and supplying a drying gas into the drying container, thereby drying the particles containing polyolefins within the drying container, and

[0012] In the above drying process, the value obtained by formula (a) is 441 or more and 600 or less.

[0013] Formula (a): 38.0 × [η]CXIS [dL / g] - 0.500 × CXIS content [mass%] + 1.20 × particle temperature during drying [K] + 3.29 × drying time [hours]

[0014] (In equation (a),

[0015] [η]CXIS represents the intrinsic viscosity of the CXIS component in particles containing polyolefins.

[0016] CXIS content indicates the amount of CXIS component in particles containing polyolefins.

[0017] [2] The drying method for polyolefin particles as described in [1], wherein the ratio of the amount of drying gas supplied to the drying container to the amount of particles (amount of drying gas [kg] / amount of particles [kg]) is 0.1 or more and 100 or less.

[0018] [3] A drying method for particles containing polyolefins as described in [1] or [2], wherein the particles are granular particles.

[0019] [4] A drying method for particles containing polyolefins as described in any one of [1] to [3], wherein the temperature of the particles supplied to the drying container is 25°C or higher and 200°C or lower.

[0020] [5] A drying method for particles containing polyolefins as described in any one of [1] to [4], wherein the empty tower velocity of the gas supplied to the drying container is 0.5 cm / s or more and 100 cm / s or less.

[0021] [6] A drying method for particles containing polyolefins as described in any one of [1] to [5], wherein, prior to performing the drying process, a granulation process is further included in which the particles are manufactured by a granulation apparatus provided with one or more exhaust ports.

[0022] [7] The drying method for particles containing polyolefins as described in [6] further includes a pre-drying step before performing the granulation step described above.

[0023] [8] The drying method for particles containing polyolefins as described in [7], wherein it is carried out in the following manner:

[0024] The drying time in the pre-drying process is at least 0.01 times that in the drying process described above.

[0025] The particle temperature in the pre-drying process is at least 0.5 times the particle temperature [K] during the drying process described above, and

[0026] The ratio of the amount of drying gas to the amount of particles supplied in the pre-drying process (amount of drying gas [kg] / amount of particles [kg]) is at least 0.1 times that in the drying process.

[0027] [9] A drying method for particles containing polyolefins as described in any one of [1] to [8], wherein the polyolefin is a propylene polymer.

[0028]

[10] A method for manufacturing a polyolefin, wherein the method comprises a step of drying particles containing a polyolefin by any one of the drying methods described in [1] to [9].

[0029] Invention Effects

[0030] The drying method for polyolefin-containing particles according to the present invention enables stable drying even when drying large quantities of particles without the particles sticking together, and provides polyolefin-containing particles with an effectively reduced content of harmful volatile organic compounds. Attached Figure Description

[0031] Figure 1 This is a schematic diagram used to illustrate the structure of a drying container.

[0032] Label Explanation

[0033] 1. Setting surface

[0034] 10. Dry container

[0035] 100 Dry Container

[0036] 100A Cylindrical Section

[0037] 100Aa upper end

[0038] 100B Conical section

[0039] 100Ba vertex

[0040] 100Bb inclined surface

[0041] 101 Particle Supply Line

[0042] 102 Drying gas supply line

[0043] 103 Heat Exchanger

[0044] 104 Particle Discharge Pipeline

[0045] 105 Drying gas discharge line

[0046] C Central axis Detailed Implementation

[0047] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. It should be noted that the drawings are merely schematic representations of the shape, size, and arrangement of the constituent elements to a degree that allows for understanding of the invention. The present invention is not limited to the following description, and the constituent elements can be modified without departing from the spirit of the invention. In the following drawings, repeated descriptions of the symbols used for the same constituent element are sometimes omitted.

[0048] In this specification, "particles containing polyolefins" refers to particles containing 50% by mass or more of polyolefins, preferably 80% by mass or more, and more preferably 95% by mass or more of polyolefins. Examples of "polyolefins" include propylene polymers, ethylene polymers, and butene polymers. Propylene polymers are a preferred example of "polyolefins." Furthermore, "particles containing polyolefins" may contain only one type of polyolefin or two or more types of polyolefins. In the case of polyolefins in "particles containing polyolefins," the content of propylene polymers in the polyolefin is preferably 30% by mass or more, more preferably 60% by mass or more, and even more preferably 90% by mass or more.

[0049] In this specification, "α-olefin" refers to an aliphatic unsaturated hydrocarbon having a carbon-carbon unsaturated double bond at the α position.

[0050] In this specification, "multiphase propylene polymeric material" refers to a mixture having a structure in which a propylene copolymer is dispersed in a matrix of a propylene polymer, wherein the propylene polymer contains 80% by mass or more of monomeric units derived from propylene (wherein the total mass of the propylene polymer is set to 100% by mass), and the propylene copolymer contains monomeric units derived from at least one α-olefin selected from the group consisting of ethylene and α-olefins having 4 or more and 12 or fewer carbon atoms, and monomeric units derived from propylene.

[0051] In this specification, "AA~BB" means AA and below. Here, AA and BB each represent numerical values, and AA < BB. Unless otherwise stated, the unit of AA is the same as the unit immediately following BB.

[0052] In this specification, the term "monomer unit" refers to a structural unit having a structure obtained by polymerizing the monomer.

[0053] In this specification, the intrinsic viscosity (unit: dL / g) is a value determined by using tetrahydronaphthalene as a solvent at a temperature of 135°C using the following method.

[0054] Specific viscosity was measured at multiple concentrations using an Ubbelohde viscometer. The specific viscosity was plotted against concentration, and the intrinsic viscosity was determined by extrapolation, with the concentration extrapolated to zero. More specifically, the method described on page 491 of "Polymer Solutions, Polymer Experimentation 11" (published by Kyoritsu Publishing Co., Ltd. in 1982) was used to measure specific viscosity at three points with concentrations of 0.1 g / dL, 0.2 g / dL, and 0.5 g / dL. The specific viscosity was plotted against concentration, and the intrinsic viscosity was determined by extrapolation, with the concentration extrapolated to zero.

[0055] 1. Drying method for particles containing polyolefins

[0056] The drying method for polyolefin-containing particles in this embodiment is as follows: the drying method for polyolefin-containing particles includes the following drying steps: feeding polyolefin-containing particles into a drying container and supplying a drying gas into the drying container, thereby drying the polyolefin-containing particles in the drying container, and in the above drying steps, the value obtained by the following formula (a) is 441 or more and 600 or less.

[0057] Formula (a): 38.0 × [η]CXIS [dL / g] - 0.500 × CXIS content [mass%] + 1.20 × particle temperature during drying [K] + 3.29 × drying time [hours]

[0058] (In equation (a),

[0059] [η]CXIS represents the intrinsic viscosity of the CXIS component in particles containing polyolefins.

[0060] CXIS content indicates the amount of CXIS component in particles containing polyolefins.

[0061] In this embodiment, there are no particular limitations on the properties of the "polyolefin-containing particles". The "polyolefin-containing particles" are preferably in granular form, but can also be in powder form.

[0062] Here, we will first explain propylene polymers that can form "particles containing polyolefins".

[0063] (1) Propylene polymers

[0064] Propylene polymers are polymers containing more than 50% by mass of propylene units relative to all structural units of the polymer. The content of propylene units in propylene polymers is typically less than 100% by mass.

[0065] Examples of propylene polymers include propylene homopolymers and copolymers of propylene and other monomers capable of copolymerizing with propylene. These copolymers can be random copolymers or block copolymers. A random copolymer is a polymer in which monomer units derived from at least one α-olefin selected from the group consisting of ethylene and α-olefins having 4 to 12 carbon atoms are randomly bonded to monomer units derived from propylene. A block copolymer is a polymer containing blocks formed by the continuous bonding of monomer units derived from at least one α-olefin selected from the group consisting of ethylene and α-olefins having 4 to 12 carbon atoms, and blocks formed by the continuous bonding of monomer units derived from propylene.

[0066] Propylene polymers may contain only one type of propylene polymer, or they may contain two or more types of propylene polymers in any combination.

[0067] Examples of propylene polymers consisting of only one type of propylene polymer include: propylene homopolymers and random copolymers of propylene and other monomers that can copolymerize (hereinafter also referred to as propylene copolymers).

[0068] In this embodiment, the propylene polymer is preferably a multiphase propylene polymer. Here, a multiphase propylene polymer refers to a material containing two or more propylene polymers, wherein these two or more propylene polymers are incompatible and form mutually distinct phases. The multiphase propylene polymer of this embodiment will be specifically described below.

[0069] (Multiphase propylene polymer materials)

[0070] The preferred multiphase propylene polymer material of this embodiment is a multiphase propylene polymer material containing propylene polymer a and propylene copolymer b, wherein propylene polymer a contains 80% by mass or more of monomer units derived from propylene, and propylene copolymer b contains monomer units derived from propylene and 20% to 70% by mass of monomer units derived from at least one α-olefin selected from the group consisting of ethylene and α-olefins having 4 or more and 12 or fewer carbon atoms.

[0071] The propylene polymer a can be, for example, a propylene homopolymer, or it can contain monomer units derived from monomers other than propylene. When the propylene polymer a contains monomer units derived from monomers other than propylene, the content of monomer units derived from monomers other than propylene, based on the total mass of the propylene polymer a, can be, for example, greater than or equal to 0.01% by mass and less than 20% by mass.

[0072] Examples of monomers other than propylene include ethylene and α-olefins having 4 or more but less than 12 carbon atoms. Preferably, at least one of the group consisting of ethylene and α-olefins having 4 to 10 carbon atoms is selected; more preferably, at least one of the group consisting of ethylene, 1-butene, 1-hexene, and 1-octene is selected; and even more preferably, at least one of the group consisting of ethylene and 1-butene is selected.

[0073] Examples of propylene polymers that contain monomer units derived from monomers other than propylene include: propylene-ethylene copolymers, propylene-1-butene copolymers, propylene-1-hexene copolymers, propylene-1-octene copolymers, propylene-ethylene-1-butene copolymers, propylene-ethylene-1-hexene copolymers, and propylene-ethylene-1-octene copolymers.

[0074] As the propylene polymer a, propylene homopolymer, propylene-ethylene copolymer, propylene-1-butene copolymer, and propylene-ethylene-1-butene copolymer are preferred, and propylene homopolymer is more preferred.

[0075] The multiphase propylene polymer material of this embodiment may contain only one propylene polymer a, or it may contain two or more propylene polymers a.

[0076] In the propylene copolymer b, the content of monomer units derived from at least one α-olefin selected from the group consisting of ethylene and α-olefins having 4 or more and 12 carbon atoms can be 20% to 70% by mass, 30% to 60% by mass, or 35% to 55% by mass.

[0077] In the propylene copolymer b, the α-olefin is selected from the group consisting of ethylene and α-olefins having 4 or more and 12 carbon atoms, preferably at least one selected from the group consisting of ethylene and α-olefins having 4 to 10 carbon atoms, more preferably at least one selected from the group consisting of ethylene, 1-butene, 1-hexene, 1-octene and 1-decene, and even more preferably at least one selected from the group consisting of ethylene and 1-butene.

[0078] Examples of propylene copolymers b include: propylene-ethylene copolymers, propylene-ethylene-1-butene copolymers, propylene-ethylene-1-hexene copolymers, propylene-ethylene-1-octene copolymers, propylene-ethylene-1-decene copolymers, propylene-1-butene copolymers, propylene-1-hexene copolymers, propylene-1-octene copolymers, and propylene-1-decene copolymers. Among these, propylene-ethylene copolymers, propylene-1-butene copolymers, or propylene-ethylene-1-butene copolymers are preferred as propylene copolymer b, and propylene-ethylene copolymers are more preferred.

[0079] The multiphase propylene polymer material of this embodiment may contain only one propylene copolymer b, or it may contain two or more propylene copolymers b.

[0080] Examples of multiphase propylene polymerization materials used in this embodiment include: (propylene)-(propylene-ethylene) polymerization materials, (propylene)-(propylene-ethylene-1-butene) polymerization materials, (propylene)-(propylene-ethylene-1-hexene) polymerization materials, (propylene)-(propylene-ethylene-1-octene) polymerization materials, (propylene)-(propylene-1-butene) polymerization materials, (propylene)-(propylene-1-hexene) polymerization materials, (propylene)-(propylene-1-octene) polymerization materials, (propylene)-(propylene-1-decene) polymerization materials, and (... Propylene-ethylene)-(propylene-ethylene) polymer materials, (propylene-ethylene)-(propylene-ethylene-1-butene) polymer materials, (propylene-ethylene)-(propylene-ethylene-1-hexene) polymer materials, (propylene-ethylene)-(propylene-ethylene-1-octene) polymer materials, (propylene-ethylene)-(propylene-ethylene-1-decene) polymer materials, (propylene-ethylene)-(propylene-1-butene) polymer materials, (propylene-ethylene)-(propylene-1-hexene) polymer materials, (propylene-ethylene)-(propylene-1-octene) polymer materials , (propylene-ethylene)-(propylene-1-decene) polymer materials, (propylene-1-butene)-(propylene-ethylene) polymer materials, (propylene-1-butene)-(propylene-ethylene-1-butene) polymer materials, (propylene-1-butene)-(propylene-ethylene-1-hexene) polymer materials, (propylene-1-butene)-(propylene-ethylene-1-octene) polymer materials, (propylene-1-butene)-(propylene-ethylene-1-decene) polymer materials, (propylene-1-butene)-(propylene-1-butene) polymer materials, (propylene-1-butene)-(propylene-1-butene) polymer materials, (propylene-1-butene) (Propylene-1-hexene) polymer materials, (Propylene-1-butene)-(Propylene-1-octene) polymer materials, (Propylene-1-butene)-(Propylene-1-decene) polymer materials, (Propylene-1-hexene)-(Propylene-1-hexene) polymer materials, (Propylene-1-hexene)-(Propylene-1-octene) polymer materials, (Propylene-1-hexene)-(Propylene-1-decene) polymer materials, (Propylene-1-octene)-(Propylene-1-octene) polymer materials and (Propylene-1-octene)-(Propylene-1-decene) polymer materials. Among them, the preferred materials are (propylene)-(propylene-ethylene) polymers, (propylene)-(propylene-ethylene-1-butene) polymers, (propylene-ethylene)-(propylene-ethylene) polymers, (propylene-ethylene)-(propylene-ethylene-1-butene) polymers, or (propylene-1-butene)-(propylene-1-butene) polymers, with (propylene)-(propylene-ethylene) polymers being more preferred.

[0081] Here, the above description indicates "(a type of propylene polymer containing 80% by mass or more of monomer units derived from propylene) - (a type of propylene copolymer b)". That is, the description of "(propylene)-(propylene-ethylene) polymeric material" indicates "a multiphase propylene polymeric material in which propylene polymer a is a propylene homopolymer and propylene copolymer b is a propylene-ethylene copolymer". The same applies to other similar descriptions.

[0082] (2) Manufacturing method of multiphase propylene polymer materials

[0083] The method for manufacturing a multiphase propylene polymer containing 80% by mass or more of propylene-derived monomer units is preferably comprising step 1, namely step 1-a and step 1-b. Furthermore, the method for manufacturing a multiphase propylene polymer preferably comprises step 1 and step 2.

[0084] (Process 1-a)

[0085] In step 1-a, for example, a liquid-phase polymerization reactor is used to polymerize a monomer containing propylene in the presence of a polymerization catalyst and hydrogen. The composition of the monomer used in the polymerization can be appropriately adjusted based on the type and content of the monomer units constituting the propylene polymer a. The propylene content in the monomer can be, for example, 80% by mass or more, 90% by mass or more, or even 100% by mass, relative to the total mass of the monomer.

[0086] Examples of liquid-phase polymerization reactors include circulating liquid-phase reactors and container-type liquid-phase reactors.

[0087] Examples of polymerization catalysts include Ziegler-Natta type catalysts and metallocene catalysts, with Ziegler-Natta type catalysts being preferred. Examples of Ziegler-Natta type catalysts include Ti-Mg-based catalysts, such as those obtained by contacting a titanium compound with a magnesium compound; and catalysts containing a solid catalyst component obtained by contacting a titanium compound with a magnesium compound, an organoaluminum compound, and a third component such as an electron-donating compound, preferably catalysts containing a solid catalyst component obtained by contacting a titanium compound with a magnesium compound, an organoaluminum compound, and a third component such as an electron-donating compound, and more preferably catalysts containing a solid catalyst component obtained by contacting a titanium halide compound with a magnesium compound, an organoaluminum compound, and an electron-donating compound. A catalyst pre-activated by contacting a small amount of olefin can also be used as a polymerization catalyst.

[0088] As a polymerization catalyst, a prepolymerization catalyst component obtained by prepolymerizing an olefin in the presence of the above-mentioned solid catalyst component, n-hexane, triethylaluminum, tert-butyl-n-propyldimethoxysilane, etc., may also be used. The olefin used in the prepolymerization is preferably any of the olefins constituting the multiphase propylene polymer material.

[0089] The polymerization temperature can be set, for example, from 0°C to 120°C. The polymerization pressure can be set, for example, from atmospheric pressure to 10 MPaG.

[0090] (Process 1-b)

[0091] In step 1-b, for example, a gas-phase polymerization reactor is used to polymerize propylene-containing monomers in the presence of a polymerization catalyst and hydrogen. The composition of the monomers used in the polymerization can be appropriately adjusted based on the type and content of the monomer units constituting the propylene polymer a. The propylene content in the monomers can be, for example, 80% by mass or more, 90% by mass or more, or even 100% by mass, relative to the total mass of the monomers.

[0092] Examples of gas-phase polymerization reactors include fluidized bed reactors and spouted bed reactors.

[0093] A gas-phase polymerization reactor can be a multi-stage gas-phase polymerization reactor with multiple reaction zones connected in series. A multi-stage gas-phase polymerization reactor can also be a multi-stage gas-phase polymerization reactor with multiple polymerization tanks connected in series.

[0094] A multi-stage gas-phase polymerization reactor, for example, has a cylindrical section and a conical constricted section. The cylindrical section extends vertically during use, and the conical constricted section is integrally formed with the cylindrical section. The inner diameter decreases towards the lower vertical direction, and a gas inlet is provided at the lower end. The multi-stage gas-phase polymerization reactor can have a sputtered bed type olefin polymerization reaction zone and a fluidized bed type olefin polymerization reaction zone. The sputtered bed type olefin polymerization reaction zone is surrounded by the inner surface of the constricted section and the inner surface of the cylindrical section, which is located above the constricted section, and a sputtered bed is formed inside it.

[0095] A multi-stage gas-phase polymerization reactor preferably has multiple reaction zones along the vertical direction. From the viewpoint of optimizing the intrinsic viscosity of propylene polymer a, the multi-stage gas-phase polymerization reactor preferably has, for example, multiple reaction zones along the vertical direction, wherein the uppermost stage is a fluidized bed type olefin polymerization reaction zone, and the rest are multiple spouted bed type olefin polymerization reaction zones. In such a reactor, for example, solid components such as catalysts are supplied from the upper side of the reactor, and gaseous components are supplied from the lower side of the reactor, thereby forming a fluidized bed or spouted bed in the reaction zone. The gaseous components may contain inert gases such as nitrogen, in addition to propylene monomers and hydrogen. In this reactor, the number of spouted bed type olefin polymerization reaction zones is preferably three or more.

[0096] In a multi-stage gas-phase polymerization reactor, where multiple reaction zones are arranged vertically, the next-stage reaction zone can be positioned obliquely below the previous-stage reaction zone. In such a reactor, for example, the solid components obtained in the previous-stage reaction zone are discharged obliquely downwards, and the discharged solid components are supplied obliquely upwards to the next-stage reaction zone. In this case, for the gaseous components, for example, the gaseous components discharged from the upper part of the next-stage reaction zone are supplied from the lower part of the previous-stage reaction zone.

[0097] Specific examples of polymerization catalysts that can be used in multi-stage gas-phase polymerization reactors are the same as those described previously.

[0098] The polymerization temperature can be, for example, 0℃~120℃, 20℃~100℃, or 40℃~100℃. The polymerization pressure can be, for example, atmospheric pressure~10MPaG, or 1MPaG~5MPaG.

[0099] (Process 2)

[0100] Step 2 can be carried out in either the gas phase or the liquid phase. Step 2 is preferably carried out in the gas phase. When step 2 is carried out in the gas phase, a gas-phase reactor such as a fluidized bed reactor or a spouted bed reactor can be used. When step 2 is carried out in the liquid phase, a liquid-phase reactor such as a circulating reactor or a vessel reactor can be used.

[0101] In step 2, for example, the same polymerization catalyst as described can be used in the presence of hydrogen to polymerize a monomer containing propylene and at least one α-olefin selected from the group consisting of ethylene and α-olefins having 4 or more and 12 or fewer carbon atoms. The composition of the monomers used in the polymerization can be appropriately adjusted based on the type and content of the monomer units constituting the propylene copolymer b. The content of at least one α-olefin selected from the group consisting of ethylene and α-olefins having 4 or more and 12 or fewer carbon atoms in the monomers used in the polymerization can, for example, be 20% to 70% by mass, or 30% to 60% by mass, relative to the total mass of the monomers.

[0102] When polymerization is carried out in the liquid phase, the polymerization temperature is, for example, 40°C to 100°C, and the polymerization pressure is, for example, atmospheric pressure to 5 MPaG. When polymerization is carried out in the gas phase, the polymerization temperature is, for example, 40°C to 100°C, and the polymerization pressure is, for example, 0.5 MPaG to 5 MPaG.

[0103] Propylene polymer a and propylene copolymer b can be produced in separate processes to deactivate the polymerization catalyst, and then the propylene polymer a and propylene copolymer b can be mixed in a solution state, a molten state, or other conditions. Alternatively, the resulting polymer can be fed to the next process without deactivating the polymerization catalyst, thereby continuously polymerizing to obtain the polymer. When polymerization is carried out continuously without deactivating the polymerization catalyst, the polymerization catalyst in the previous process can usually also function as the polymerization catalyst in the subsequent process.

[0104] There are no particular restrictions on the order in which steps 1 and 2 are performed. As mentioned above, step 1 preferably includes steps 1-a and 1-b. Steps 1 and 2 are not particularly limited to being performed in the presence of hydrogen, and can also be performed in the absence of hydrogen.

[0105] The manufacturing method of the multiphase propylene polymer material of this embodiment preferably includes step 1-a, step 1-b and step 2 in sequence.

[0106] (Gas-solid separation process and catalyst deactivation process)

[0107] The propylene polymer (multiphase propylene polymer material) obtained through the above process is supplied to the gas-solid separation process and the catalyst deactivation process. Specifically, the catalyst deactivation process, which deactivates the solid catalyst components, can be carried out together with the gas-solid separation process by conveying the reaction mixture containing the propylene polymer from the polymerization reactor to a gas-solid separation vessel having any suitable structure known in the art, and supplying, for example, water vapor (steam) and nitrogen from the bottom side of the gas-solid separation vessel.

[0108] (3) Particles containing propylene polymers

[0109] In this embodiment, the particles containing propylene polymers (particles containing multiphase propylene polymer materials) may also contain any suitable additives known in the public, such as heat stabilizers, ultraviolet stabilizers, antioxidants, crystal nucleating agents, lubricants, colorants, antiblocking agents, antistatic agents, antifogging agents, flame retardants, petroleum resins, foaming agents, foaming aids, organic fillers, and inorganic fillers, as needed.

[0110] The amount of additive added is preferably 0.01% by mass or more relative to the total amount (100% by mass) of particles containing propylene polymers (particles containing multiphase propylene polymer materials), and preferably 30% by mass or less. One additive may be used alone, or two or more additives may be used in combination.

[0111] (4) Drying method for particles containing propylene polymers

[0112] The drying method for particles containing propylene polymers (hereinafter sometimes simply referred to as "particles") according to this embodiment includes the following drying steps: feeding particles containing propylene polymers into a drying container and supplying a drying gas into the drying container, thereby drying the particles containing propylene polymers inside the drying container.

[0113] The particle drying process in this embodiment may include a pre-drying process and a formal drying process.

[0114] Here, firstly, refer to Figure 1 Structural examples of drying containers used in the drying process, namely the pre-drying process and the formal drying process described later, will be explained. In the following description, a structural example of a cylindrical portion of the drying container as the main body will be described, but the present invention is not limited thereto. Regarding the shape of the drying container, and especially the shape of the main body, it can be any suitable shape according to the design, such as a cuboid shape, without impairing the effectiveness of the present invention.

[0115] Figure 1 This is a schematic diagram used to illustrate the structure of a drying container.

[0116] like Figure 1 As shown, the drying container 10 includes a hollow drying container 100, which is composed of a cylindrical portion 100A and a conical portion 100B integrally connected to the cylindrical portion 100A and having a apex 100Ba and an inclined surface 100Bb.

[0117] When in use, the drying container 100 is configured such that the lower end of the cone 100B is the apex 100Ba, and the upper end 100Aa is the end of the cylindrical portion 100A opposite to the side connecting the cone 100B. More specifically, the drying container 100 is configured such that its central axis C, passing through the center of the apex 100Ba of the cone 100B and the center of the upper end 100Aa of the cylindrical portion 100A, is orthogonal to the horizontal mounting surface 1.

[0118] A particle supply line 101 is connected to the upper end 100Aa of the cylindrical portion 100A of the drying container 100. The particle supply line 101 is a structure for introducing the object to be dried, such as particles containing polyolefins, or more specifically, propylene polymers such as multiphase propylene polymers, or particles containing propylene polymers, into the drying container 100.

[0119] A drying gas discharge line 105 is connected to the upper end 100Aa of the cylindrical portion 100A of the drying container 100. The drying gas discharge line 105 is a structure for introducing the drying gas supply line 102 (described later) into the drying container 100 and for discharging the drying gas after drying the object to the outside of the drying container 100.

[0120] A particle discharge line 104 is connected to the apex 100Ba of the conical portion 100B of the drying container 100. The particle discharge line 104 is a structure for discharging the dried object after drying treatment outside the drying container 100.

[0121] A drying gas supply line 102 is connected to the inclined surface 100Bb of the conical portion 100B of the drying container 100. In this structural example, the drying gas supply line 102 branches into two lines and connects to two points on the inclined surface 100Bb. The drying gas supply line 102 is a structure for drying by supplying drying gas into the drying container 100 and bringing the drying gas into contact with the object to be dried.

[0122] A heat exchanger 103 is provided on the upstream side of one of the branches of the drying gas supply line 102. The heat exchanger 103 is a structure for heating the drying gas supplied to the drying container 100 through the drying gas supply line 102, thereby raising the temperature of the drying gas to a specified temperature. As the heat exchanger 103, any suitable device known in the art can be selected.

[0123] The particle supply line 101, particle discharge line 104, drying gas supply line 102, and drying gas discharge line 105 can adopt any suitable existing structure including pipes, valves, etc. Furthermore, the particle supply line 101, particle discharge line 104, drying gas supply line 102, and drying gas discharge line 105 can be configured in any suitable arrangement, shape, and size according to desired methods.

[0124] (Pre-drying process)

[0125] In the particle drying method of this embodiment, when the particles are in granular form, the granulation step described later is performed. In this case, the particle drying method of this embodiment preferably includes a pre-drying step before performing the granulation step.

[0126] Preferably, the drying time in the pre-drying process is at least 0.01 times that in the drying process (the formal drying process described later). That is, the drying time in the pre-drying process is preferably shorter than the drying time in the formal drying process described later.

[0127] In this embodiment, the pre-drying process and the drying process (the formal drying process described later) are preferably implemented as either batch drying processes or continuous drying processes. Here, a batch drying process refers to the following steps: feeding particles into the drying container 100, drying by contacting the drying gas with the object to be dried for any amount of time, and discharging the dried object (particles) outside the drying container 100. A continuous drying process refers to the following steps: retaining any amount of the object to be dried (particles) in the drying container 100, then feeding particles into the drying container 100 at any supply rate, feeding drying gas into the drying container, and simultaneously contacting the particles in the drying container 100 with the drying gas while discharging the dried particles outside the drying container 100 at any discharge rate.

[0128] Preferably, the particle temperature in the pre-drying process is at least 0.5 times the particle temperature [K] in the formal drying process. That is, the particle temperature in the pre-drying process is preferably lower than the particle temperature in the formal drying process.

[0129] Here, the temperature of the particles in the pre-drying process and the drying process is preferably below the melting point of the polyolefin, which is the main component of the particles. For example, if the particles contain multiple polyolefins, it is preferable to set the conditions of the pre-drying process and the drying process in such a way that the temperature of the particles is below the melting point of the polyolefin with the highest content in the particles.

[0130] Preferably, the ratio of the amount of drying gas to the amount of particles supplied in the pre-drying process (amount of drying gas [kg] / amount of particles [kg]) is at least 0.1 times that in the formal drying process.

[0131] Here, when the pre-drying process is a batch drying process, "amount of particles supplied" refers to the total amount of particles [kg] supplied to the drying container during the batch drying process, and "amount of drying gas" refers to the total amount [kg] of drying gas supplied to the drying container during the batch drying process.

[0132] In addition, when the pre-drying process is a continuous drying process, "the amount of particles supplied" is the average amount of particles supplied to the drying container per unit time [kg / hour] during the continuous drying process after a specified amount of the object to be dried (particles) has been retained in the drying container, and "the amount of drying gas" is the average amount of drying gas supplied to the drying container per unit time [kg / hour] during the continuous drying process of supplying the object to be dried (particles).

[0133] In this embodiment, any suitable gas known in the art can be used as the drying gas supplied to the drying container. As the drying gas, a non-reactive gas such as nitrogen is preferred, and air is even more preferred. Especially since residual solvent may exist in the pre-drying process, a non-reactive gas such as nitrogen is preferred. In the formal drying process, sometimes more drying gas is used than in the pre-drying process, so air is preferred.

[0134] In the pre-drying process of this embodiment (and the formal drying process described later), the "empty tower velocity [m / s]" of the drying gas refers to the total flow rate [m] of the drying gas that can be supplied to the drying container. 3 / s] divided by the area of ​​the cross-section (circular in the case of a cylindrical part) extending in the direction of the flow of the drying gas along the direction orthogonal to the extension direction (vertical direction) of the main body (cylindrical part) of the drying container [m 2 The calculated speed. It should be noted that when the cross-section extending in the direction of the drying gas flow, perpendicular to the extension direction (vertical direction) of the main body of the drying container, varies depending on the height of the extension direction of the main body, the area of ​​this cross-section [m²]... 2 This is the value obtained by dividing the volume of the drying container by the height of the drying container in the direction of its extension.

[0135] In this embodiment, a process of cooling the particles under any suitable conditions may be further implemented between the pre-drying process and the granulation process described later, or between the pre-drying process and the formal drying process described later.

[0136] (Granulation process)

[0137] The granulation process in this embodiment can be performed using any suitable granulation apparatus that is currently known.

[0138] The particles of this embodiment can be manufactured by melt-blending, for example, using the described propylene polymer and additives as raw material components. The temperature during melt-blending can be 180°C or higher, or 180°C to 300°C, or 180°C to 250°C.

[0139] Examples of granulation apparatuses used to manufacture, in particular, granular particles for this embodiment, include, for example, a Banbury internal mixer, a single-screw extruder, and a twin-screw co-rotating extruder.

[0140] There are no particular restrictions on the mixing order of the raw material components. For example, all raw material components can be fed into the granulation unit together for mixing, or a portion of the selected raw material components can be mixed, and then the resulting mixture can be mixed with other raw material components.

[0141] In this embodiment, the granulation apparatus used in the granulation process preferably has one or more exhaust ports. Here, an exhaust port is a functional unit capable of removing gases and volatile components by venting them out of the system. In particular, a vacuum exhaust port is a functional unit capable of actively venting gases and volatile components out of the system and removing them by depressurizing the pressure inside the granulation apparatus. The exhaust port in this embodiment can be any suitable structure known in the art.

[0142] In this embodiment, the granulation device can have an exhaust port that can be an atmospheric exhaust port, a vacuum exhaust port, or a combination of an atmospheric exhaust port and a vacuum exhaust port.

[0143] In this embodiment, at least one of the more than one exhaust ports that the granulation apparatus can have is preferably a vacuum exhaust port.

[0144] When the granulation apparatus has at least one vacuum exhaust port, the granulation process is preferably carried out by using the vacuum exhaust port to reduce the pressure inside the granulation apparatus to above -95 kPa and below -5 kPa.

[0145] (Formal drying process)

[0146] If a pre-drying process and a granulation process have been performed, a formal drying process (drying process) is carried out after these processes using the described drying apparatus.

[0147] In the formal drying process (drying process) of this embodiment, the temperature of the particles supplied to the drying container is preferably 25°C or higher and 200°C or lower. More preferably, the temperature of the particles supplied to the drying container is 100°C or lower.

[0148] Here, "the temperature of the particles supplied to the drying container" refers to the temperature of the particles before they are supplied to the drying container. In the case where the particles are supplied to the drying container online by means of air conveying, it refers to the temperature of the particles before air conveying.

[0149] In the formal drying process (drying process) of this embodiment, the temperature of the particles being dried in the drying container (particle temperature during drying) is preferably 50°C or higher and 200°C or lower. More preferably, the temperature of the particles being dried in the drying container is 80°C or higher, and even more preferably 100°C or higher. Furthermore, the temperature of the particles being dried in the drying container is more preferably 160°C or lower, and even more preferably 125°C or lower.

[0150] Here, in the case of a batch drying process, "particle temperature during drying" refers to the average particle temperature inside the drying container from the end of particle feeding into the drying container and the start of feeding drying gas into the drying container until the particles begin to be discharged from the drying container. It should be noted that the particle temperature can be obtained by measuring the temperature of the area inside the drying container filled with particles. If the temperature is measured at multiple locations inside the drying container, the average value can be taken as the particle temperature during drying.

[0151] Furthermore, in the case of a continuous drying process, "particle temperature during drying" refers to the average temperature of the particles present in the drying container during the continuous drying process, in which particles are continuously supplied to and discharged from the drying container at a specified rate (flow rate). It should be noted that the particle temperature can be obtained by measuring the temperature of the area within the drying container filled with particles. If the temperature is measured at multiple locations within the drying container, the average value can be used as the particle temperature during drying.

[0152] In the formal drying process (drying process) of this embodiment, the empty tower velocity of the gas supplied to the drying container is preferably 0.5 cm / s or more and 100 cm / s or less. From the viewpoint of suppressing particles from scattering outside the drying container, the empty tower velocity of the gas supplied to the drying container is more preferably 50 cm / s or less.

[0153] In the formal drying process (drying process) of this embodiment, the drying time is preferably 0.2 hours or more and 48 hours or less. More preferably, the drying time is 1.0 hour or more, and even more preferably 5.0 hours or more. More preferably, the drying time is 24 hours or less, and even more preferably 15 hours or less.

[0154] Here, when the drying process is a batch drying process, "drying time" refers to the total time from the end of feeding particles into the drying container and the start of feeding drying gas into the drying container until the start of discharging the dried particles out of the drying container. Conversely, when the drying process is a continuous drying process, "drying time" is a value calculated by dividing the average amount of particles retained in the drying container [kg] during the continuous drying process by the average discharge rate of particles discharged from the drying container [kg / hour] during the continuous drying process. It should be noted that "continuous drying process" refers to the period from the following start time to the following end time, wherein the start time is defined as the moment when drying gas is supplied into the drying container while a specified amount of particles are present in the drying container, and the moment when the dried particles are discharged out of the drying container, and the end time is defined as the moment when the feeding of particles into the drying container stops and the discharge of particles stops.

[0155] The ratio of the amount of drying gas supplied to the drying container to the amount of particles (amount of drying gas [kg] / amount of particles [kg]) is preferably 0.1 or more and 100 or less, more preferably 0.3 or more, even more preferably 1.0 or more, more preferably 75 or less, and even more preferably 50 or less.

[0156] Here, when the drying process is a batch drying process, "the ratio of the amount of drying gas supplied to the drying container to the amount of particles (amount of drying gas [kg] / amount of particles [kg])" refers to the ratio of the total amount of drying gas supplied to the drying container during the batch drying process to the total amount of particles [kg] supplied to the drying container during the batch drying process. When the drying process is a continuous drying process, "the ratio of the amount of drying gas supplied to the drying container to the amount of particles (amount of drying gas [kg] / amount of particles [kg])" refers to the ratio of the average amount of drying gas supplied to the drying container per unit time [kg / hour] during the continuous drying process after a specified amount of the object to be dried (particles) has been retained in the drying container to the average amount of particles supplied to the drying container per unit time [kg / hour] during the continuous drying process.

[0157] In the drying process of this embodiment, the value obtained by the following formula (a) is preferably 441 or more and 600 or less, and the lower limit of the value is more preferably 460 or more, and even more preferably 480 or more. In addition, the upper limit of the value is more preferably 580 or less, and even more preferably 560 or less.

[0158] Formula (a): 38.0 × [η]CXIS [dL / g] - 0.500 × CXIS content [mass%] + 1.20 × particle temperature during drying [K] + 3.29 × drying time [hours]

[0159] In equation (a), [η]CXIS represents the intrinsic viscosity of the CXIS component in the particles containing propylene polymers, and the CXIS content represents the content of the CXIS component in the particles containing propylene polymers.

[0160] Here, CXIS (cold xylene insoluble part) refers to the xylene-insoluble component. Conversely, CXS (cold xylene soluble part) refers to the xylene-soluble component.

[0161] Specifically, CXIS components refer to the components in the analyte (propylene polymers, particles containing propylene polymers) that are particularly insoluble in p-xylene, for example, components that can be obtained by the separation methods described below. CXS components refer to the remaining components after separating the CXIS components from the analyte.

[0162] (Separation Method)

[0163] A solution was obtained by dissolving approximately 2g of a propylene polymer (containing propylene polymer particles) in boiling p-xylene for 2 hours. The resulting solution was then cooled to 20°C, and the solid substance precipitated from the cooled solution was identified as the CXIS component.

[0164] When the total mass of the polyolefin-containing particles is set to 100% by mass, the content of the CXIS component (CXIS content) is preferably 20% to 100% by mass, more preferably 30% to 100% by mass, further preferably 40% to 100% by mass, more preferably 50% to 100% by mass, and particularly preferably 60% to 100% by mass.

[0165] It should be noted that the intrinsic viscosities [η]CXIS and [η]CXS of the CXIS and CXS components can be determined using any suitable apparatus known to the public by the described intrinsic viscosity determination method.

[0166] (6) Median particle size

[0167] In this embodiment, the median particle size is preferably 500 μm to 2000 μm.

[0168] In this embodiment, the median particle size can be determined by laser diffraction particle size distribution measurement or vibrating sieve particle size distribution measurement. These methods will be described below.

[0169] (Laser diffraction particle size distribution determination method)

[0170] In this embodiment, the median particle size can be determined, for example, using a laser diffraction particle size distribution measuring device (e.g., HELOS / KF, sample disperser: GRADIS+VIBRI, manufactured by Sympatec).

[0171] Specifically, the particle size distribution can be measured by feeding approximately 1g to 10g of particle sample into a particle size distribution measuring device and determining the particle size distribution. The analysis software (e.g., Windows version 5.3.1.0) can then be used to calculate the median particle size (D) based on the volumetric standard. 50 Alternatively, the above samples can be measured 3 to 5 more times, and the average value of these measurements can be used as the average median particle size.

[0172] (Vibrating sieve method for particle size distribution determination)

[0173] In this embodiment, when measuring the average median particle size, the average median particle size can be calculated by measuring the particle size distribution using sieving, wherein the particles are sieved based on particle size by gravity from a mesh that opens at the bottom of the sieve by vibrating the sieve.

[0174] Specifically, as described below.

[0175] First, multiple sieves with different mesh sizes are stacked, starting from the largest mesh size and gradually decreasing to the smallest mesh size from top to bottom.

[0176] Next, the sample is placed into the top sieve, and then all sieves are vibrated four times for 5 minutes with an amplitude of 1.0 mm, which enables sieving.

[0177] As a sieve, for example, sieves with aperture sizes of 5600μm, 4750μm, 4000μm, 3350μm, 2360μm, 2000μm, 1700μm, 1400μm, 1180μm, 1000μm, 850μm, 710μm, 500μm, 300μm, and 150μm can be used (JIS Z 8801, manufactured by Manabe Kogyo Co., Ltd.).

[0178] Sample quantities of 100g or more are acceptable. For the vibrating sieve, the Retsch AS200 electromagnetic vibrating sieve can be used.

[0179] The determination can be performed by weighing the sample remaining on each sieve.

[0180] Specifically, as described below.

[0181] Weigh the amount of sample remaining on each sieve after vibration. It should be noted that the amounts of sample remaining on each sieve are added sequentially, starting with the sieve with the largest mesh size. Here, the sieve whose total value exceeds 50% of the total sample amount fed into the sieve is designated as sieve b. The sieve preceding sieve b is designated as sieve a.

[0182] Based on the above measurements, the average median particle size (D) can be calculated using the following formula. 50 ).

[0183] D 50 =Da-[(Da-Db)×{(xb-50) / (xb-xa)}]

[0184] If no residue exceeds 50% of the total amount of sample put in on any of the sieves, designate the sieve with the largest amount of residual sample as sieve b, and designate the sieve above sieve b as sieve a.

[0185] In the above formula, Da represents the sieve aperture size of sieve a [μm], and Db represents the sieve aperture size of sieve b [μm]. xa represents the mass percentage of the total sample remaining on sieve a and the sieves above sieve a relative to the total sample amount [mass%], and xb represents the mass percentage of the total sample remaining on sieve b and the sieves above sieve b relative to the total sample amount [mass%].

[0186] Example

[0187] The present invention will now be described in more detail through embodiments. The present invention is not limited to the embodiments described below.

[0188] The determination and evaluation methods in the examples and comparative examples are described below.

[0189] [Ethylene unit content (unit: mass%)]

[0190] The content of ethylene units in multiphase propylene polymer materials was determined by IR spectroscopy, which is described in the Polymer Handbook (published by Kinokuniya Shoten in 1995) on page 619.

[0191] Here, "ethylene unit" refers to monomer units derived from ethylene. The ethylene unit content [mass %] in the propylene-ethylene copolymer is obtained by dividing the content of ethylene-derived monomer units in the multiphase propylene polymer material (called ethylene unit content) by the mass ratio [mass %] of the propylene-ethylene copolymer in the multiphase propylene polymer material and multiplying by 100.

[0192] [Evaluation based on equation (a)]

[0193] (Separation Method)

[0194] A solution was obtained by dissolving approximately 2g of a propylene polymer (containing propylene polymer particles) in boiling p-xylene for 2 hours. The resulting solution was then cooled to 20°C, and the solid substance precipitated from the cooled solution was identified as the CXIS component.

[0195] Based on the CXIS components obtained as described above, the specified parameters ([η]CXIS, CXIS content) are obtained, and the values ​​obtained by applying these parameters to the above equation (a) are evaluated to see if they are 441 or more and 600 or less.

[0196] [Reference Example 1] (Preparation of solid catalyst components)

[0197] The atmosphere in a 100 mL flask equipped with a stirrer, dropping funnel, and thermometer was purged with nitrogen. Then, 36.0 mL of toluene and 22.5 mL of titanium tetrachloride were added to the flask, and the mixture was stirred to obtain a titanium tetrachloride solution. The temperature of the flask was adjusted to 0 °C, and then 1.88 g of magnesium diethanoloxide was added in four portions at 30-minute intervals at 0 °C. The mixture was then stirred at 0 °C for 1.5 hours.

[0198] Next, 0.60 mL of ethyl 2-ethoxymethyl-3,3-dimethylbutyrate was added to the flask, and then the temperature inside the flask was raised to 10°C.

[0199] Then, the mixture was stirred at 10°C for 2 hours, and 9.8 mL of toluene was added. Next, the temperature inside the flask was raised, and at 60°C, 3.15 mL of ethyl 2-ethoxymethyl-3,3-dimethylbutyrate was added, and the temperature was further raised to 110°C. The mixture was then stirred at 110°C for 3 hours.

[0200] The resulting mixture was subjected to solid-liquid separation to obtain a solid. The obtained solid was washed three times with 56.3 mL of toluene at 100 °C.

[0201] 38.3 mL of toluene was added to the washed solid to form a slurry. 15.0 mL of titanium tetrachloride and 0.75 mL of ethyl 2-ethoxymethyl-3,3-dimethylbutyrate were added to the slurry to form a mixture, which was then stirred at 110 °C for 1 hour. The mixture was then subjected to solid-liquid separation. The obtained solid was washed three times with 56.3 mL of toluene at 60 °C, and further washed three times with 56.3 mL of hexane at room temperature. The washed solid was then dried under reduced pressure to obtain the solid catalyst component.

[0202] The obtained solid catalyst composition contains 2.53% titanium atoms, 0.44% ethoxy atoms, and 13.7% internal electron donors.

[0203] In addition, the median particle size of the solid catalyst composition determined by laser diffraction / scattering was 59.5 μm, and the cumulative percentage of solid catalyst composition with a particle size of less than 10 μm was 5.3% in the volume-based particle size distribution.

[0204] In the solid catalyst composition, the peak content generated by the 1s orbital of oxygen atoms with a binding energy range of 532 eV to 534 eV, as determined by XPS analysis, was 85.0%, and the peak content with a binding energy range of 529 eV to 532 eV was 15.0%.

[0205] In the solid catalyst composition, the total pore volume determined by mercury porosimetry was 1.43 mL / g, the total pore volume in the pore size range of 5 nm to 30 nm was 0.160 mL / g, the total pore volume in the pore size range of 30 nm to 700 nm was 0.317 mL / g, and the specific surface area was 107.44 m². 2 / g.

[0206] [Example 1] (Preparation of multiphase propylene polymer material A)

[0207] <Prepolymerization Process>

[0208] 1.5L of fully dehydrated and degassed n-hexane, 45 mmol of triethylaluminum (TEA), and 4.5 mmol of tert-butyl-n-propyldimethoxysilane are contained in a 3L stainless steel (SUS) autoclave equipped with a stirrer.

[0209] 18g of the solid catalyst component manufactured in Reference Example 1 above was added to the autoclave, and then a prepolymerization process was carried out in which 18g of propylene was continuously supplied for about 30 minutes while the temperature inside the autoclave was maintained at about 10°C.

[0210] Then, the slurry obtained through the prepolymerization process is transported to a 260L SUS316L autoclave equipped with a stirrer, and 180L of liquid butane is added to further produce the slurry.

[0211] <Main Polymerization Process>

[0212] In the main polymerization process, an apparatus is used that consists of a slurry polymerization reactor, a multi-stage gas-phase polymerization reactor, and a gas-phase polymerization reactor connected in series.

[0213] The main polymerization process is carried out through polymerization steps 1-a, 1-b, and 2. Specifically, it is carried out as follows: in polymerization steps 1-a and 1-b, a propylene polymer a, which is a propylene homopolymer, is polymerized; the resulting propylene polymer a and the solid catalyst component are then transported to the next stage polymerization reactor without deactivating them, and in polymerization step 2, a propylene copolymer b, which is a propylene-ethylene copolymer, is polymerized. Polymerization steps 1-a, 1-b, and 2 will be described in detail below.

[0214] (Polymerization step 1-a) (Homopolymerization of propylene using a slurry polymerization reactor)

[0215] Homopolymerization of propylene was carried out using a SUS304 container-type slurry polymerization reactor equipped with a stirrer.

[0216] Specifically, the raw materials (propylene, hydrogen, solid catalyst components, TEA, and tert-butyl-n-propyl dimethoxysilane) are continuously fed into the reactor to carry out the polymerization reaction. The reaction conditions are as follows.

[0217] Polymerization temperature: 50℃

[0218] Mixing speed: 150 rpm

[0219] Liquid level in the slurry polymerization reactor: 18L

[0220] Propylene supply rate: 25 kg / hour

[0221] Hydrogen supply: 83.1 NL / hour

[0222] TEA supply: 28.4 mmol / h

[0223] Supply rate of tert-butyl-n-propyl dimethoxysilane: 5.53 mmol / h

[0224] The feed rate of the prepolymerization process slurry to the reactor (converted based on solid catalyst composition) is 0.75 g / hour.

[0225] Polymerization pressure: 3.56 MPa (gauge pressure)

[0226] The intrinsic viscosity [η]L1 of the product (propylene homopolymer) sampled from the outlet of the slurry polymerization reactor was 0.85 dL / g.

[0227] (Polymerization step 1-b) (Homopolymerization of propylene using a multi-stage gas-phase polymerization reactor)

[0228] The homopolymerization of propylene is carried out using a multi-stage gas-phase polymerization reactor, which has six reaction zones along the vertical direction, with the uppermost stage being a fluidized bed and the remaining five stages being sputtered beds.

[0229] Specifically, a slurry containing particulate propylene homopolymer and liquid propylene generated through polymerization step 1-a is transported from the previous stage slurry polymerization reactor and continuously supplied to the fluidized bed, which is the uppermost stage of the multi-stage gas-phase polymerization reactor, without deactivating it.

[0230] Interstage transport of propylene homopolymer within the multistage gas-phase polymerization reactor is achieved via a dual-valve system. This dual-valve system works as follows: a 1-inch diameter pipe connects the preceding and following reaction zones. Two on / off valves are installed in the pipe. With the downstream valve closed, the upstream valve is opened, temporarily accumulating powder from the preceding reaction zone between the valves. Then, the upstream valve is closed, and the downstream valve is opened, thereby transporting particulate propylene homopolymer to the following reaction zone.

[0231] Propylene and hydrogen are continuously supplied from the bottom side of the multi-stage gas-phase polymerization reactor with the above-described structure. This forms a fluidized bed or sputtered bed in each reaction zone of the multi-stage reaction zone, controlling the supply of propylene and hydrogen in a manner that maintains constant gas composition and pressure, and discharging excess gas, while simultaneously further homopolymerizing propylene. The reaction conditions are as follows.

[0232] Polymerization temperature: 70℃

[0233] Polymerization pressure: 1.80 MPa (gauge pressure)

[0234] Gas concentration ratio (hydrogen / (hydrogen + propylene)): 12.9 mol%

[0235] The intrinsic viscosity [η]G1 of the product (propylene homopolymer) sampled from the outlet of the multi-stage gas-phase polymerization reactor is 0.83 dL / g. [η]L1 and [η]G1 are essentially the same value. Therefore, in Example 1, the propylene homopolymer generated through the implementation of polymerization step 1-b is propylene polymer a, and [η]G1 is the intrinsic viscosity of propylene polymer a.

[0236] (Polymerization Step 2) (Propylene-ethylene copolymerization using a gas-phase polymerization reactor (gas-phase polymerization))

[0237] The propylene polymer a discharged from the multi-stage gas-phase polymerization reactor used in polymerization step 1-b is continuously supplied to the next-stage gas-phase polymerization reactor. The gas-phase polymerization reactor used in polymerization step 2 is a reactor equipped with a gas dispersion plate, and the particulate propylene polymer a from the previous multi-stage gas-phase polymerization reactor is conveyed to the gas-phase polymerization reactor via the described dual-valve method.

[0238] Propylene, ethylene, and hydrogen are continuously supplied to the gas-phase polymerization reactor with the above-described structure. The gas supply is adjusted to maintain a constant gas composition and pressure, and excess gas is discharged. Simultaneously, propylene and ethylene copolymerize in the presence of propylene polymer a, thereby generating a propylene-ethylene copolymer b, resulting in a multiphase propylene polymer material A, which is a mixture of propylene polymer a and propylene copolymer b. The reaction conditions are as follows.

[0239] Polymerization temperature: 70℃

[0240] Polymerization pressure: 1.75 MPa (gauge pressure)

[0241] Gas concentration ratio (ethylene / (propylene + ethylene)): 34.1 mol%

[0242] (Hydrogen / (Hydrogen + Propylene + Ethylene)): 3.2 mol%

[0243] Regarding the proportion (X) of propylene copolymer b (propylene-ethylene copolymer) in the obtained multiphase propylene polymeric material A, the heat of fusion for crystallization of propylene polymer a and the entire multiphase propylene polymeric material A was measured separately and calculated using the following formula. Here, the heat of fusion for crystallization was measured by differential scanning calorimetry (DSC).

[0244] X = 1 - (ΔHf)T / (ΔHf)P

[0245] (ΔHf)T: Heat of fusion of the entire multiphase propylene polymer material A [J / g]

[0246] (ΔHf)P: Heat of fusion of propylene polymer a [J / g]

[0247] The intrinsic viscosity [η]G2 of the product (multiphase propylene polymer material A) sampled from the outlet of the gas-phase polymerization reactor was 1.36 dL / g.

[0248] Based on the above, the intrinsic viscosity [η]C of propylene copolymer b is calculated using the following formula.

[0249] [η]C=([η]G2-[η]G1×(1-X)) / X

[0250] The obtained multiphase propylene polymer A has an intrinsic viscosity ([η]Total) of 1.36 dL / g and an ethylene unit content of 11.5% by mass. Furthermore, the polymerization ratio of propylene polymer a to propylene copolymer b is 72 / 28 [mass% / mass%]. The ethylene content in propylene copolymer b is 42% by mass, and the intrinsic viscosity [η]C of propylene copolymer b is 2.8 dL / g.

[0251] <Gas-solid separation process and catalyst deactivation process>

[0252] The multiphase propylene polymer material A obtained in the above polymerization step 2 is transported from the gas-phase polymerization reactor to the SUS gas-solid separation vessel, and water vapor (steam) and nitrogen are supplied from the bottom side of the gas-solid separation vessel, thereby performing a catalyst deactivation process to deactivate the solid catalyst components together with the gas-solid separation process.

[0253] <Pre-drying process>

[0254] The multiphase propylene polymer material A, after undergoing the gas-solid separation process and catalyst deactivation process as described above, is transported to a drying container made by SUS. Nitrogen gas is supplied into the drying container as a drying gas, and a batch pre-drying process is carried out under the following conditions.

[0255] The temperature of the multiphase propylene polymer A supplied to the drying container: 40℃

[0256] The temperature of the supplied nitrogen gas is 80℃ (353.15K).

[0257] The flow rate of nitrogen supplied: 0.8 kg / kg

[0258] Nitrogen gas velocity in the empty tower: 0.025 m / s

[0259] Temperature of multiphase propylene polymer material A: 53℃

[0260] Drying time: 1 hour

[0261] <Granulation Process>

[0262] Using a twin-screw extruder (TEX44αII) manufactured by Nippon Steel Works Co., Ltd. as the granulation unit, the multiphase propylene polymer material A, which underwent the pre-drying process as described above, and the raw material components shown in Table 2 were mixed and granulated into granules under the granulation conditions shown in Table 1 below, in the proportions shown in Table 2 below, thereby obtaining particles A containing propylene polymers (hereinafter referred to as particles A). It should be noted that the physical properties of the obtained particles A are shown in Table 3 below. The amount of volatile organic compounds listed in Table 1 is the amount of volatile organic compounds in the multiphase propylene polymer material A before granulation, and the amount of volatile organic compounds listed in Table 3 is the amount of volatile organic compounds in particles A obtained by granulation.

[0263] [Table 1]

[0264]

[0265] [Table 2]

[0266]

[0267] [Table 3]

[0268]

[0269] <Formal Drying Process>

[0270] The obtained particle A is then introduced into the reference. Figure 1 In the described drying container, the formal drying process is carried out in batches under the conditions shown in Table 10 below.

[0271] (Determination of the amount of volatile organic compounds)

[0272] The amount of volatile organic compounds (VOCs) was determined using HS-GC / FID under the following conditions. Specifically, components detected within 10 minutes were quantified using n-heptane conversion, and their total value was determined as the amount of VOCs. It should be noted that the amount of VOCs is expressed as a mass percentage relative to particle A [mass ppm].

[0273] HS conditions

[0274] Measurement apparatus: HS-20 headspace sampler (manufactured by Shimadzu Corporation)

[0275] Heating temperature / hour: 120℃ / 60 minutes

[0276] Sample size: 1.0g

[0277] GC conditions

[0278] Measurement apparatus: Gas chromatograph GC-2010PlusAF (manufactured by Shimadzu Corporation)

[0279] Column: DB-WAX 0.53mm×60m×1.0μm

[0280] Oven: Inject the gas phase at 50°C, heat to 100°C at a heating rate of 5°C / min, further heat to 230°C at a heating rate of 20°C / min, and hold for 5 minutes.

[0281] Detector: Hydrogen flame ionization detector (230℃)

[0282] The results are shown in Table 10 below. For particles A of Example 1 after the formal drying process, the volatile organic compounds (VOCs) were significantly reduced. The "amount of VOCs before drying" in Table 10 refers to the amount of VOCs before the formal drying process, and the "amount of VOCs after drying" refers to the amount of VOCs after the formal drying process. The "reduction percentage" in Table 10 is obtained by dividing the difference between the "amount of VOCs before drying" and the "amount of VOCs after drying" by the "amount of VOCs before drying" and multiplying by 100.

[0283] (Amount of air relative to the particles)

[0284] The mass of the air used is determined by the amount of air supplied to the particles [m] 3 It is calculated by multiplying the density by the density at each drying temperature.

[0285] (Adhesion ratio)

[0286] The adhesion ratio is an indicator of the degree to which particles adhere to each other. Specifically, regarding the adhesion ratio, firstly, the polyolefin-containing particles after the formal drying process are sieved using a sieve with a 4mm aperture. Then, with the total amount of polyolefin-containing particles fed into the sieve set at 100% by mass, the mass percentage [mass%] of polyolefin-containing particles that did not pass through the sieve and remained on it is calculated. The results are shown in Table 10 below.

[0287] [Examples 2-6 and Comparative Example 1]

[0288] The conditions for the formal drying process were adjusted as shown in Table 10 below, and otherwise performed in the same manner as in Example 1, thereby implementing Examples 2 to 6 and Comparative Example 1. The results are shown in Table 10 below.

[0289] [Example 7] (Preparation of Multiphase Propylene Polymer Material B)

[0290] <Prepolymerization Process>

[0291] 1.5L of fully dehydrated and degassed n-hexane, 44 mmol of TEA, and 4.4 mmol of tert-butyl-n-propyl dimethoxysilane are contained in a 3L SUS autoclave equipped with a stirrer.

[0292] 17g of the solid catalyst component manufactured in Reference Example 1 above was added to the autoclave, and then a prepolymerization process was carried out in which 17g of propylene was continuously supplied for about 30 minutes while the temperature inside the autoclave was maintained at about 10°C.

[0293] Then, the slurry obtained through the prepolymerization process is transported to a 260L SUS316L autoclave equipped with a stirrer, and 180L of liquid butane is added to further produce the slurry.

[0294] <Main Polymerization Process>

[0295] In the main polymerization process, an apparatus is used that consists of a slurry polymerization reactor, a multi-stage gas-phase polymerization reactor, and a gas-phase polymerization reactor connected in series.

[0296] The main polymerization is carried out through polymerization steps 1-a, 1-b, and 2. Specifically, it is carried out as follows: propylene polymer a, which is a homopolymer of propylene, is polymerized in polymerization steps 1-a and 1-b; the resulting propylene polymer a and solid catalyst components are then transferred to the next stage polymerization reactor without deactivating them, and polymerized in polymerization step 2 to obtain propylene copolymer b, which is a propylene-ethylene copolymer. Polymerization steps 1-a, 1-b, and 2 will be described in detail below.

[0297] (Polymerization step 1-a) (Homopolymerization of propylene using a slurry polymerization reactor)

[0298] Homopolymerization of propylene was carried out using a SUS304 container-type slurry polymerization reactor equipped with a stirrer.

[0299] Specifically, raw materials are continuously fed into the reactor to carry out the polymerization reaction. The reaction conditions are as follows.

[0300] Polymerization temperature: 50℃

[0301] Mixing speed: 150 rpm

[0302] Liquid level in the slurry polymerization reactor: 18L

[0303] Propylene supply rate: 25 kg / hour

[0304] Hydrogen supply: 70.4 NL / hour

[0305] TEA supply: 27.5 mmol / h

[0306] Supply rate of tert-butyl-n-propyl dimethoxysilane: 5.46 mmol / h

[0307] Slurry supply rate (converted based on solid catalyst composition): 0.73 g / hour

[0308] Polymerization pressure: 3.50 MPa (gauge pressure)

[0309] The intrinsic viscosity [η]L1 of the product (propylene homopolymer) sampled from the outlet of the slurry polymerization reactor was 0.96 dL / g.

[0310] (Polymerization step 1-b) (Homopolymerization of propylene using a multi-stage gas-phase polymerization reactor)

[0311] The homopolymerization of propylene is carried out using a multi-stage gas-phase polymerization reactor, which has 6 reaction zones along the vertical direction, with the uppermost stage being a fluidized bed and the remaining 5 stages being sputtered beds.

[0312] Specifically, a slurry containing particulate polypropylene and liquid propylene generated through polymerization step 1-a is conveyed from the previous stage slurry polymerization reactor and continuously supplied to the fluidized bed, which is the uppermost stage of the multi-stage gas-phase polymerization reactor, without deactivating it.

[0313] Interstage transport of propylene homopolymer within the multistage gas-phase polymerization reactor is carried out via a dual-valve system as described above.

[0314] Propylene and hydrogen are continuously supplied from the lower part of the multi-stage gas-phase polymerization reactor with the above-described structure. This forms fluidized beds or spouted beds in each reaction zone, controlling the supply of propylene and hydrogen in a manner that maintains constant gas composition and pressure, while excess gas is discharged, and propylene homopolymerization proceeds simultaneously. The reaction conditions are as follows.

[0315] Polymerization temperature: 59℃

[0316] Polymerization pressure: 1.80 MPa (gauge pressure)

[0317] The concentration ratio of the gases (hydrogen / (hydrogen + propylene)) is 10.2 mol%.

[0318] The intrinsic viscosity [η]G1 of the product (propylene homopolymer) sampled from the outlet of the multi-stage gas-phase polymerization reactor is 0.92 dL / g. [η]L1 and [η]G1 are essentially the same value. Therefore, in Example 7, the propylene homopolymer generated by proceeding up to polymerization step 1-b is propylene polymer a, and [η]G1 is the intrinsic viscosity of propylene polymer a.

[0319] (Polymerization Step 2) (Propylene-ethylene copolymerization using a gas-phase polymerization reactor (gas-phase polymerization))

[0320] The propylene polymer a discharged from the multi-stage gas-phase polymerization reactor used in polymerization step 1-b is continuously supplied to the next-stage gas-phase polymerization reactor. The gas-phase polymerization reactor used in polymerization step 2 is a reactor equipped with a gas dispersion plate, and the particulate propylene polymer a from the previous multi-stage gas-phase polymerization reactor is conveyed to the gas-phase polymerization reactor via the described dual-valve method.

[0321] Propylene, ethylene, and hydrogen are continuously supplied to the gas-phase polymerization reactor with the above-described structure. The gas supply is adjusted to maintain a constant gas composition and pressure, and excess gas is discharged. Simultaneously, propylene and ethylene copolymerize in the presence of propylene polymer a, thereby generating a propylene-ethylene copolymer b, resulting in a multiphase propylene polymer material B, which is a mixture of propylene polymer a and propylene copolymer b. The reaction conditions are as follows.

[0322] Polymerization temperature: 70℃

[0323] Polymerization pressure: 1.75 MPa (gauge pressure)

[0324] Gas concentration ratio (ethylene / (propylene + ethylene)): 41.7 mol%

[0325] (Hydrogen / (Hydrogen + Propylene + Ethylene)): 3.1 mol%

[0326] Regarding the proportion (X) of propylene copolymer b (propylene-ethylene copolymer) in the obtained multiphase propylene polymeric material B, the heat of fusion for crystallization of propylene polymer a and the entire multiphase propylene polymeric material B was measured separately and calculated using the following formula. Here, the heat of fusion for crystallization was measured by differential scanning calorimetry (DSC).

[0327] X = 1 - (ΔHf)T / (ΔHf)P

[0328] (ΔHf)T: Heat of fusion of the entire multiphase propylene polymer material B [J / g]

[0329] (ΔHf)P: Heat of fusion of propylene polymer a [J / g]

[0330] The intrinsic viscosity [η]G2 of the product (multiphase propylene polymer material B) sampled from the outlet of the gas-phase polymerization reactor was 1.93 dL / g.

[0331] Based on the above, the intrinsic viscosity [η]C of propylene copolymer b is calculated using the following formula.

[0332] [η]C=([η]G2-[η]G1×(1-X)) / X

[0333] The obtained multiphase propylene polymer material B has an intrinsic viscosity ([η]Total) of 1.93 dL / g and an ethylene unit content of 22.4% by mass. Furthermore, the polymerization ratio of propylene polymer a to propylene copolymer b is 50 / 50 [mass% / mass%]. The ethylene content in propylene copolymer b is 44% by mass, and the intrinsic viscosity [η]C of propylene copolymer b is 2.9 dL / g.

[0334] <Gas-solid separation process and catalyst deactivation process>

[0335] The multiphase propylene polymer material B obtained in the above polymerization step 2 is transported from the gas-phase polymerization reactor to the SUS gas-solid separation vessel, and water vapor (steam) and nitrogen are supplied from the bottom side of the gas-solid separation vessel, thereby performing a catalyst deactivation process to deactivate the solid catalyst components together with the gas-solid separation process.

[0336] <Pre-drying process>

[0337] The multiphase propylene polymer material B, after undergoing the gas-solid separation process and catalyst deactivation process as described above, is transported to a drying container made by SUS. Nitrogen gas is supplied into the drying container as a drying gas, and a batch pre-drying process is carried out under the following conditions.

[0338] The temperature of the multiphase propylene polymer B supplied to the drying container: 40℃

[0339] The temperature of the supplied nitrogen gas: 80℃

[0340] Nitrogen flow rate: 0.8 kg / kg

[0341] Nitrogen gas velocity in the empty tower: 0.025 m / s

[0342] Temperature of multiphase propylene polymer material B: 53℃

[0343] Drying time: 1 hour

[0344] <Granulation Process>

[0345] Using a twin-screw extruder manufactured by Nippon Steel Corporation as the granulation unit, the multiphase propylene polymer material B, which underwent the pre-drying process as described above, and the raw material components shown in Table 5 were mixed and granulated into granules under the granulation conditions shown in Table 4 below, in the proportions shown in Table 5 below, thereby obtaining particles B containing propylene polymers (hereinafter referred to as particles B). It should be noted that the physical properties of the obtained particles B are shown in Table 6 below. The amount of volatile organic compounds listed in Table 4 refers to the amount of volatile organic compounds in the multiphase propylene polymer material B before granulation, and the amount of volatile organic compounds listed in Table 6 refers to the amount of volatile organic compounds in particles B obtained through granulation.

[0346] [Table 4]

[0347]

[0348] [Table 5]

[0349] [Table 6]

[0350]

[0351] <Formal Drying Process>

[0352] The obtained particle B was then introduced into the reference. Figure 1 In the described drying container, the formal drying process is carried out in batches under the conditions shown in Table 10 below.

[0353] (Determination of the amount of volatile organic compounds)

[0354] The determination of the amount of volatile organic compounds was performed using particles B dried as described above, in the same manner as in Example 1.

[0355] The results are shown in Table 10 below. For particles B of Example 7 after the formal drying process, the amount of volatile organic compounds was significantly reduced.

[0356] [Examples 8-11 and Comparative Example 2]

[0357] The conditions for the formal drying process were adjusted as shown in Table 10 below, and otherwise performed in the same manner as in Example 7, thereby implementing Examples 8-11 and Comparative Example 2. The results are shown in Table 10 below.

[0358] [Example 12] (Preparation of propylene homopolymer C)

[0359] <Prepolymerization Process>

[0360] 1.5L of fully dehydrated and degassed n-hexane, 45 mmol of TEA, and 4.5 mmol of tert-butyl-n-propyl dimethoxysilane are contained in a 3L SUS autoclave equipped with a stirrer.

[0361] 18g of the solid catalyst component manufactured in Reference Example 1 above was added to the autoclave, and then a prepolymerization process was carried out in which 18g of propylene was continuously supplied for about 30 minutes while the temperature inside the autoclave was maintained at about 10°C.

[0362] Then, the slurry obtained through the prepolymerization process is transported to a 260L SUS316L autoclave equipped with a stirrer, and 180L of liquid butane is added to further produce the slurry.

[0363] <Main Polymerization Process>

[0364] In the main polymerization process, an apparatus consisting of a slurry polymerization reactor, a multi-stage gas-phase polymerization reactor, and a gas-phase polymerization reactor connected in series is used. Specifically, a propylene polymer a, which is a propylene homopolymer, is obtained by polymerization in polymerization steps 1-a and 1-b, and a propylene homopolymer C is obtained by further polymerization in polymerization step 1-c.

[0365] (Polymerization step 1-a) (Homopolymerization of propylene using a slurry polymerization reactor)

[0366] Homopolymerization of propylene was carried out using a SUS304 container-type slurry polymerization reactor equipped with a stirrer.

[0367] Specifically, raw materials are continuously fed into the reactor to carry out the polymerization reaction. The reaction conditions are as follows.

[0368] Polymerization temperature: 50℃

[0369] Mixing speed: 150 rpm

[0370] Reactor liquid level: 18L

[0371] Propylene supply rate: 25 kg / hour

[0372] Hydrogen supply: 160 NL / hour

[0373] TEA supply: 24.0 mmol / h

[0374] Supply rate of tert-butyl-n-propyl dimethoxysilane: 4.55 mmol / h

[0375] Slurry supply rate (converted based on solid catalyst composition): 0.71 g / hour

[0376] Polymerization pressure: 4.00 MPa (gauge pressure)

[0377] The intrinsic viscosity [η]L1 of the product (propylene homopolymer) sampled from the outlet of the slurry polymerization reactor was 0.68 dL / g.

[0378] (Polymerization process 1-b) (Homopolymerization of propylene using a multi-stage gas-phase polymerization reactor)

[0379] The homopolymerization of propylene is carried out using a multi-stage gas-phase polymerization reactor, which has 6 reaction zones along the vertical direction, with the uppermost stage being a fluidized bed and the remaining 5 stages being sputtered beds.

[0380] Specifically, a slurry containing particulate propylene homopolymer and liquid propylene generated through polymerization step 1-a is transported from the previous stage slurry polymerization reactor and continuously supplied to the fluidized bed, which is the uppermost stage of the multi-stage gas-phase polymerization reactor, without deactivating it.

[0381] Interstage transport of propylene homopolymer within the multistage gas-phase polymerization reactor is carried out via a dual-valve system as described above.

[0382] Propylene and hydrogen are continuously supplied from the bottom side of the multi-stage gas-phase polymerization reactor with the above-described structure. This forms a fluidized bed or sputtered bed in each reaction zone of the multi-stage reaction zone, controlling the supply of propylene and hydrogen in a manner that maintains constant gas composition and pressure, and discharging excess gas, while simultaneously further homopolymerizing propylene. The reaction conditions are as follows.

[0383] Polymerization temperature: 80℃

[0384] Polymerization pressure: 1.79 MPa (gauge pressure)

[0385] The concentration ratio of the gases (hydrogen / (hydrogen + propylene)) is 18.3 mol%.

[0386] The intrinsic viscosity [η]G1 of the product (propylene homopolymer) sampled from the outlet of the multi-stage gas-phase polymerization reactor is 0.64 dL / g. [η]L1 and [η]G1 are essentially the same value. Therefore, the propylene homopolymer produced through polymerization step 1-b is propylene polymer a, and [η]G1 is the intrinsic viscosity of propylene polymer a.

[0387] (Polymerization step 1-c) (Homopolymerization of propylene using a gas-phase polymerization reactor (gas-phase polymerization))

[0388] The propylene polymer a discharged from the previous stage multi-stage gas-phase polymerization reactor is continuously supplied to the next stage gas-phase polymerization reactor. This gas-phase polymerization reactor is equipped with a gas dispersion plate, and the feeding of particulate propylene polymer a from the previous stage multi-stage gas-phase polymerization reactor to the gas-phase polymerization reactor is carried out by the described dual-valve method.

[0389] Propylene and hydrogen are continuously supplied to the gas-phase polymerization reactor with the above structure. The gas supply is adjusted to maintain a constant gas composition and pressure, and excess gas is discharged. Simultaneously, propylene homopolymerization occurs in the presence of propylene polymer a, thereby generating a propylene homopolymer as propylene copolymer b, resulting in propylene homopolymer C, which is a mixture of propylene polymer a and propylene copolymer b. The reaction conditions are as follows.

[0390] Polymerization temperature: 79℃

[0391] Polymerization pressure: 1.76 MPa (gauge pressure)

[0392] The concentration ratio of the gases (hydrogen / (hydrogen + propylene)) is 0.14 mol%.

[0393] The intrinsic viscosity ([η]Total) of propylene homopolymer C is 0.99 dL / g.

[0394] <Solid-gas separation process and catalyst deactivation process>

[0395] The propylene homopolymer C obtained in the above polymerization step 1-c is transported from the gas-phase polymerization reactor to the SUS gas-solid separation vessel, and water vapor (steam) and nitrogen are supplied from the bottom side of the gas-solid separation vessel, thereby performing a catalyst deactivation process to deactivate the solid catalyst components together with the gas-solid separation process.

[0396] <Pre-drying process>

[0397] The propylene homopolymer C, after undergoing the gas-solid separation process and catalyst deactivation process as described above, is transported to a drying container made by SUS. Nitrogen gas is supplied into the drying container as a drying gas, and a batch pre-drying process is carried out under the following conditions.

[0398] The temperature of propylene homopolymer C supplied to the drying container: 40℃

[0399] The temperature of the supplied nitrogen gas is 80℃ (353.15K).

[0400] Nitrogen flow rate: 0.8 kg / kg

[0401] Nitrogen gas velocity in the empty tower: 0.025 m / s

[0402] Temperature of propylene homopolymer C: 53℃

[0403] Drying time: 1 hour

[0404] <Granulation Process>

[0405] Using a twin-screw extruder manufactured by Nippon Steel Corporation as the granulation unit, the propylene homopolymer C, after undergoing the pre-drying process as described above, was mixed with the raw material components shown in Table 8 at the proportions shown in Table 8 under the granulation conditions shown in Table 7 below, and granulated into granules to obtain particles C containing propylene polymers (hereinafter referred to as particles C). It should be noted that the physical properties of the obtained particles C are shown in Table 9 below. The amounts of volatile organic compounds listed in Table 7 are the amounts of volatile organic compounds in the propylene homopolymer C before granulation, and the amounts of volatile organic compounds listed in Table 9 are the amounts of volatile organic compounds in the particles C obtained through granulation.

[0406] [Table 7]

[0407]

[0408] [Table 8]

[0409]

[0410] [Table 9]

[0411]

[0412] *The amount of CXS is too small to determine [η]CXS.

[0413] <Formal Drying Process>

[0414] The obtained particle C was then introduced into the reference. Figure 1 In the described drying container, the formal drying process is carried out in batches under the conditions shown in Table 10 below.

[0415] (Determination of the amount of volatile organic compounds)

[0416] The determination of the amount of volatile organic compounds was performed using particles C dried as described above, in the same manner as in Example 1.

[0417] The results are shown in Table 10 below. For particles C of Example 12 after the formal drying process, the amount of volatile organic compounds was significantly reduced.

[0418] [Example 13 and Comparative Examples 3-4]

[0419] The conditions for the formal drying process were adjusted as shown in Table 10 below, and otherwise performed in the same manner as in Example 12, thereby implementing Example 13 and Comparative Examples 3-4. The results are shown in Table 10 below.

[0420] [Example 14]

[0421] Example 14 was carried out by adjusting the conditions of the formal drying process as shown in Table 10 below, except that it was performed in the same manner as in Example 7. The results are shown in Table 10 below. The adhesion rate of the polyolefin-containing particles after the formal drying process was 5.6% by mass, therefore, the degree of adhesion was very light, and there were no problems in carrying out the manufacturing process.

[0422] [Comparative Example 6]

[0423] Comparative Example 6 was performed by adjusting the conditions of the formal drying process as shown in Table 10 below, except that it was carried out in the same manner as in Example 7. The results are shown in Table 10 below. The adhesion ratio of the polyolefin-containing particles after the formal drying process was 76.4% by mass, and the polyolefin-containing particles formed large, coarse agglomerates after the formal drying process. When a large number of agglomerates are formed like this, there are concerns about pipe blockage during the manufacturing process.

[0424]

Claims

1. A method for drying particles containing polyolefins, wherein, The drying method for the polyolefin-containing particles includes the following drying steps: feeding the polyolefin-containing particles into a drying container and supplying a drying gas into the drying container, thereby drying the polyolefin-containing particles within the drying container. In the drying process, the value obtained by the following formula (a) is 441 or more and 600 or less. Equation (a): 38.0 × [η]CXIS - 0.500 × CXIS content + 1.20 × particle temperature during drying + 3.29 × drying time In equation (a), [η]CXIS represents the intrinsic viscosity of the CXIS component in particles containing polyolefins. CXIS content indicates the content of CXIS component in particles containing polyolefins. The CXIS component refers to the xylene-insoluble component. The unit of [η]CXIS is dL / g. The CXIS content is expressed in % by mass. The temperature of the particles during drying is measured in Kelvin (K). The drying time is measured in hours.

2. The drying method for polyolefin-containing particles as described in claim 1, wherein, The ratio of the amount of drying gas supplied to the drying container to the amount of particles, i.e., the amount of drying gas / the amount of particles, is 0.1 or more and 100 or less, and the units for both the amount of drying gas and the amount of particles are kg.

3. The drying method for polyolefin-containing particles as described in claim 1, wherein, The particles are granular.

4. The drying method for polyolefin-containing particles as described in claim 1, wherein, The temperature of the particles supplied to the drying container is above 25°C and below 200°C.

5. The drying method for polyolefin-containing particles as described in claim 1, wherein, The empty tower velocity of the gas supplied to the drying container is above 0.5 cm / s and below 100 cm / s.

6. The drying method for polyolefin-containing particles as described in claim 1, wherein, Prior to the drying process, a granulation process is also included, in which the particles are manufactured by a granulation device having one or more exhaust ports.

7. The drying method for polyolefin-containing particles as described in claim 6, wherein, A pre-drying process is also included before the granulation process.

8. The drying method for polyolefin-containing particles as described in claim 7, wherein, Implemented in the following manner: The drying time in the pre-drying process is at least 0.01 times the drying time in the drying process. The particle temperature in the pre-drying process is at least 0.5 times the particle temperature during the drying process, and the unit of particle temperature is K. The ratio of the amount of drying gas to the amount of particles supplied in the pre-drying process, expressed as the amount of drying gas in kg / the amount of particles in kg, is at least 0.1 times the ratio of the amount of drying gas to the amount of particles supplied in the drying process, expressed as the amount of drying gas in kg / the amount of particles in kg.

9. The drying method for polyolefin-containing particles as described in claim 1, wherein, The polyolefin is a propylene polymer.

10. A method for manufacturing a polyolefin, wherein, The method for manufacturing the polyolefin includes a step of drying the polyolefin-containing particles by the drying method according to any one of claims 1 to 9.

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