Propylene homopolymer, unstretched sheet, uniaxially stretched film, biaxially stretched film, method for producing propylene homopolymer, and pellet

Abstract

The present invention addresses the problem of providing: a propylene homopolymer which has relatively excellent uniform stretchability; an unstretched sheet; a uniaxially stretched film; a biaxially stretched film; a method for producing a propylene homopolymer; and a pellet.　The present invention relates to a propylene homopolymer which has a half-value width (Hw) of a melting peak of 7.7°C or more as measured using a differential scanning calorimeter (DSC), a melting point (Tm) of 159.0°C to 170.0°C inclusive, and a molecular weight distribution (Mw / Mn) of 4.1 or more.

Description

Propylene homopolymer, unstretched sheet, uniaxially stretched film, biaxially stretched film, method for producing propylene homopolymer, and pellets

[0001] The present invention relates to a propylene homopolymer, an unstretched sheet, a uniaxially stretched film, a biaxially stretched film, a method for producing a propylene homopolymer, and pellets.

[0002] A conventional stretched film is oriented polypropylene film (hereinafter also referred to as "OPP"). OPP is formed into a film by stretching a raw material, propylene polymer. OPP has excellent moisture resistance and transparency, and is therefore used, for example, as food packaging bags.

[0003] In recent years, in order to produce OPP with better performance, the development of propylene polymers as raw materials for OPP has been investigated. For example, Patent Document 1 describes a propylene polymer that can be used to produce OPP with excellent rigidity and transparency.

[0004] International Publication No. 2018 / 069541

[0005] In the production of OPP, a propylene homopolymer that can be uniformly stretched is desired in order to prevent the stretched film from breaking during production, but it cannot be said that a propylene homopolymer that can be uniformly stretched has been sufficiently studied.

[0006] Therefore, an object of the present invention is to provide a propylene homopolymer, an unstretched sheet, a uniaxially stretched film, a biaxially stretched film, a method for producing a propylene homopolymer, and pellets, all of which have relatively excellent uniform stretchability.

[0007] The propylene homopolymer according to the present invention has a melting peak half width (H ) measured using a differential scanning calorimeter (DSC). ｗ ) is 7.7°C or higher, and the melting point (T ｍ ) is 159.0°C or more and 170.0°C or less, and the molecular weight distribution (Mw / Mn) is 4.1 or more.

[0008] The unstretched sheet according to the present invention contains the propylene homopolymer.

[0009] The uniaxially stretched film according to the present invention contains the propylene homopolymer.

[0010] The biaxially stretched film according to the present invention contains the propylene homopolymer.

[0011] The method for producing a propylene homopolymer according to the present invention comprises a step of obtaining a propylene homopolymer by homopolymerization in the presence of an olefin polymerization catalyst obtained by contacting a solid catalyst component for olefin polymerization (A), an organoaluminum compound (B), and a silicon compound (C), wherein the solid catalyst component for olefin polymerization (A) contains a titanium atom, a magnesium atom, a halogen atom, and an internal electron donor, the internal electron donor is at least one selected from the group consisting of a monoester compound, a diester compound, a diol diester compound, a β-alkoxy ester compound, and a diether compound, the silicon compound (C) is represented by the following formula (i) or (ii), and the molar ratio of the organoaluminum compound (B) to the silicon compound (C) is 100:1 to 1000:1. １ ｎ Si(OR ２ ) ４－ｎ ... (i) (R １ is a hydrocarbyl group having 1 to 20 carbon atoms or a hydrogen atom. ２ is a hydrocarbyl group having 1 to 20 carbon atoms, and n is an integer satisfying the condition 0≦n≦2. １ If there are multiple １ may be the same or different. ２ If there are multiple ２ may be the same or different.) R ３ ｍ Si(NR ４ R ５ ) ４－ｍ ... (ii) (R ３ is a hydrocarbyl group having 1 to 20 carbon atoms, an alkoxy group, or a hydrogen atom. ４ and R ５is a hydrocarbyl group having 1 to 12 carbon atoms or a hydrogen atom, and m is an integer satisfying the condition 0≦m≦4. ３ If there are multiple ３ may be the same or different. ４ If there are multiple ４ may be the same or different. ５ If there are multiple ５ may be the same or different.)

[0012] The propylene homopolymer according to the present invention is a propylene homopolymer obtained by using an olefin polymerization catalyst obtained by contacting a solid catalyst component for olefin polymerization (A), an organoaluminum compound (B), and a silicon compound (C), wherein the solid catalyst component for olefin polymerization (A) contains a titanium atom, a magnesium atom, a halogen atom, and an internal electron donor, the internal electron donor is at least one compound selected from the group consisting of a monoester compound, a diester compound, a diol diester compound, a β-alkoxy ester compound, and a diether compound, the silicon compound (C) is represented by the following formula (i) or (ii), and the molar ratio of the organoaluminum compound (B) to the silicon compound (C) is 100:1 to 1000:1. １ ｎ Si(OR ２ ) ４－ｎ ... (i) (R １ is a hydrocarbyl group having 1 to 20 carbon atoms or a hydrogen atom. ２ is a hydrocarbyl group having 1 to 20 carbon atoms, and n is an integer satisfying the condition 0≦n≦2. １ If there are multiple １ may be the same or different. ２ If there are multiple ２ may be the same or different.) R ３ ｍ Si(NR ４ R ５ ) ４－ｍ ... (ii) (R ３is a hydrocarbyl group having 1 to 20 carbon atoms, an alkoxy group, or a hydrogen atom. ４ and R ５ is a hydrocarbyl group having 1 to 12 carbon atoms or a hydrogen atom, and m is an integer satisfying the condition 0≦m≦4. ３ If there are multiple ３ may be the same or different. ４ If there are multiple ４ may be the same or different. ５ If there are multiple ５ may be the same or different.)

[0013] The pellets according to the present invention contain a propylene homopolymer and an antioxidant, and have a melting peak half width (H ) measured using a differential scanning calorimeter (DSC). ｗ ) is 7.7°C or higher, and the melting point (T ｍ ) is 159.0°C or more and 170.0°C or less, and the molecular weight distribution (Mw / Mn) is 4.1 or more.

[0014] According to the present invention, there are provided a propylene homopolymer having relatively excellent uniform stretchability, an unstretched sheet, a uniaxially stretched film, a biaxially stretched film, a method for producing a propylene homopolymer, and pellets.

[0015] Hereinafter, embodiments of the present invention will be described, but the present invention is not limited to the following embodiments.

[0016] [Propylene homopolymer] The half-width (H ) of the melting peak of the propylene homopolymer according to this embodiment measured using a differential scanning calorimeter (DSC) ｗ ) is 7.7°C or higher, preferably 8.0°C or higher and 20.0°C or lower, and more preferably 8.0°C or higher and 15.0°C or lower.

[0017] The half-width of the melting peak (H ｗ) can be measured by differential scanning calorimetry. Pellets of propylene homopolymer are preheated using a heat press at 230°C for 5 minutes, pressurized at 230°C for 5 minutes at a pressure of 5 MPa, and cooled at 25°C to 27°C for 5 minutes to produce a pressed sheet with a thickness of 0.2 mm. 5 mg of the pressed sheet sample is sealed in an aluminum pan, and using a TA Instruments DSC D250 or TA Instruments DSC Q2000, the sample is heated to 230°C under a nitrogen atmosphere (first heating), held at 230°C for 5 minutes, cooled from 230°C to 0°C at 5°C / min, and heated from 0°C to 230°C at 5°C / min (second heating). A straight line connecting the 20°C point and the 200°C point is subtracted as a baseline from the melting endothermic curve obtained in the second heating to obtain a corrected melting endothermic curve. The peak width at the midpoint of the height from the X axis to the maximum peak top of the corrected melting endothermic curve is called the half-width of the melting peak (H ｗ The temperature is corrected by assuming that the melting point of indium is 156.6°C and the heat of fusion of indium is 28.71 J / K. In the above measurement method, pellets of propylene homopolymer are used, and the half width (H ｗ ) is substantially the same as the measured value when the propylene homopolymer itself is measured.

[0018] The propylene homopolymer according to this embodiment has a melting peak half width (H ｗ ) is within the above range, excellent uniform stretchability can be obtained.

[0019] The half-width (H) of the melting peak of the propylene homopolymer measured using a differential scanning calorimeter (DSC) ｗ The half-width (H) of the melting peak of the propylene homopolymer measured by a differential scanning calorimeter (DSC) can be increased by decreasing the ratio of the silicon compound (C) to the organoaluminum compound (B) described later, and can be decreased by increasing the ratio of the silicon compound (C) to the organoaluminum compound (B). ｗ ) can be increased by using two or more different silicon compounds (C).

[0020] The melting point (T ｍ ) is 159.0°C or higher and 170.0°C or lower, preferably 159.0°C or higher and 168.0°C or lower, and more preferably 159.5°C or higher and 165.0°C or lower.

[0021] Melting point (T ｍ ) is measured by differential scanning calorimetry. Pellets of propylene homopolymer are preheated using a heat press at 230 ° C for 5 minutes, pressurized at 230 ° C for 5 minutes at a pressure of 5 MPa, and cooled at 25 ° C to 27 ° C for 5 minutes to prepare a pressed sheet with a thickness of 0.2 mm. 5 mg of the pressed sheet sample is sealed in an aluminum pan, and using a TA Instruments DSC D250 or TA Instruments DSC Q2000, the sample is heated to 230 ° C under a nitrogen atmosphere (first heating), held at 230 ° C for 5 minutes, cooled from 230 ° C to 0 ° C at 5 ° C / min, and heated from 0 ° C to 230 ° C at 5 ° C / min (second heating). TA Universal Analysis (TA Instruments) is used as the analysis software. The temperature of the maximum peak of the melting endothermic curve obtained in the second heating is the melting point (T ｍ The temperature is corrected by assuming that the melting point of indium is 156.6°C and the heat of fusion of indium is 28.71 J / K. In the above measurement method, pellets of propylene homopolymer are used, and the melting point (T ｍ ) is substantially the same as the measured value when the propylene homopolymer itself is measured.

[0022] The propylene homopolymer according to this embodiment has a melting point (T ｍ ) is within the above range, excellent uniform stretchability can be obtained.

[0023] Melting point of propylene homopolymer (T ｍ ) can be increased by increasing the ratio of the silicon compound (C) to the organoaluminum compound (B), and can be decreased by decreasing the ratio of the silicon compound (C) to the organoaluminum compound (B). ｍ) is R in the silicon compound (C) described below. １ ~R ５ When is a hydrocarbyl group or an alkoxy group, the higher the value can be, the bulkier the hydrocarbyl group or alkoxy group has.

[0024] The molecular weight distribution (Mw / Mn) of the propylene homopolymer according to this embodiment is 4.1 or more, preferably 4.5 or more and 10.0 or less, and more preferably 4.5 or more and 8.0 or less.

[0025] The molecular weight distribution of propylene homopolymer can be measured using gel permeation chromatography (GPC) under the following conditions. Peaks are designated by defining the baseline on the chromatogram based on the description of ISO 16014-1. (GPC Apparatus and Software) Apparatus: HLC-8321GPC / HT (Tosoh Corporation) Software: HLC-8321 GPC / HT Program Version 2.02 (Tosoh Corporation) (Measurement Conditions) GPC Column: TSKgel GMHHR-H(S)HT 7.8 mm ID x 300 mm (Tosoh Corporation) x 3 Mobile Phase: o-dichlorobenzene (Fujifilm Wako Pure Chemical Industries, Ltd., Special Grade) to which dibutylhydroxytoluene (BHT) has been added to achieve a BHT concentration of 0.1 g / 100 mL. Flow rate: 1 mL / min Column oven temperature: 140°C Autosampler temperature: 140°C System oven temperature: 40°C Detection: Refractive index detector (RID) RID cell temperature: 140°C Sample solution injection volume: 300 μL (Sample solution preparation conditions) A BHT-containing orthodichlorobenzene solution of the same composition as the mobile phase is used. Sample solution concentration: 1 mg / mL Dissolution conditions: 5 mg of sample is sealed in a 1000 mesh SUS wire mesh bag, and the wire mesh bag containing propylene homopolymer pellets as the sample is placed in a test tube. 5 mL of solvent is added to the test tube, the test tube is covered with aluminum foil, and the test tube is placed in a DF-8020 automatic dissolution shaker (manufactured by Tosoh Corporation) and stirred at a stirring rate of 60 reciprocations per minute at 140°C for 120 minutes. (Analysis Method) Standard polystyrene (manufactured by Tosoh Corporation) was weighed out as a standard substance for calibrating a GPC column in the combinations shown in Table 1, and 5 mL of a BHT-containing orthodichlorobenzene solution having the same composition as the mobile phase was added, followed by standing at room temperature for 120 minutes to dissolve.

[0026]

[0027] Using a calibration curve obtained from a standard substance, the polystyrene-equivalent average molecular chain lengths An and Aw of the propylene homopolymer are calculated. The polystyrene-equivalent average molecular chain lengths are each multiplied by the polypropylene Q factor of 26.4 to determine the polypropylene-equivalent average molecular weights (number average molecular weight (Mn) and weight average molecular weight (Mw)). The ratio (Mw / Mn) of the number average molecular weight (Mn) to the weight average molecular weight (Mw) is calculated as an index of molecular weight distribution. Note that although pellets of propylene homopolymer are used in the above measurement method, the molecular weight distribution obtained by the above measurement method is substantially the same as the measurement value when the propylene homopolymer itself is measured.

[0028] The propylene homopolymer according to this embodiment has a molecular weight distribution (Mw / Mn) within the above range, and therefore has excellent uniform stretchability.

[0029] The molecular weight distribution (Mw / Mn) of the propylene homopolymer can be increased by decreasing the ratio of the silicon compound (C) to the organoaluminum compound (B), and can be decreased by increasing the ratio of the silicon compound (C) to the organoaluminum compound (B). The molecular weight distribution (Mw / Mn) of the propylene homopolymer can also be increased by mixing two or more propylene homopolymers having different molecular weights.

[0030] The propylene homopolymer according to the present embodiment has structural units derived from propylene. The stereoregularity of the propylene homopolymer according to the present embodiment may be any one of isotactic, syndiotactic, and atactic, or a combination thereof.

[0031] The stereoregularity of the propylene homopolymer according to this embodiment is preferably syndiotactic or isotactic from the viewpoint of heat resistance.

[0032] The isotactic pentad fraction of the propylene homopolymer according to this embodiment is preferably 0.950 or less, more preferably 0.900 or more and 0.940 or less, and even more preferably 0.900 or more and 0.930 or less.

[0033] The isotactic pentad fraction of propylene homopolymer is determined under the following conditions: １３ Measurement can be performed by C-NMR. The assignment of NMR absorption peaks of propylene homopolymer is performed according to the method published by A. Zambelli et al. (Macromolecules, Vol. 8, p. 687, 1975). Model: Bruker AVANCE 600; Probe: 10 mm cryoprobe; Measurement temperature: 135°C; Pulse repetition time: 4 seconds; Pulse width: 45°; Number of accumulations: 256

[0034] The propylene homopolymer according to this embodiment has an isotactic pentad fraction within the above range, so that it can obtain better uniform stretchability.

[0035] The isotactic pentad fraction can be increased by increasing the ratio of the silicon compound (C) to the organoaluminum compound (B), and can be decreased by decreasing the ratio of the silicon compound (C) to the organoaluminum compound (B). １ ~R ５ When is a hydrocarbyl group or an alkoxy group, the higher the value can be, the bulkier the hydrocarbyl group or alkoxy group has.

[0036] The isothermal crystallization time (T １／２ ) is preferably 100.0 s or less, more preferably 30.0 s or more and 95.0 s or less, and even more preferably 60.0 s or more and 90.0 s or less.

[0037] The isothermal crystallization time of the propylene homopolymer can be measured using a differential scanning calorimeter (PerkinElmer DSC DSC8500). A 10 mg sample is placed in a nitrogen atmosphere and isothermal crystallization is carried out at a crystallization temperature of 120°C. The peak-top time of the obtained endothermic curve (1 / 2 isothermal crystallization time) is taken as the isothermal crystallization time. A shorter isothermal crystallization time indicates a faster crystallization rate. Although pellets of the propylene homopolymer are used in the above measurement method, the isothermal crystallization time obtained by the above measurement method is substantially the same as that measured when the propylene homopolymer itself is measured.

[0038] The propylene homopolymer according to this embodiment has an isothermal crystallization time (T １／２ ) is within the above range, more excellent uniform stretchability can be obtained.

[0039] The isothermal crystallization time (T １／２ ) can be increased by increasing the ratio of the silicon compound (C) to the organoaluminum compound (B), and can be decreased by decreasing the ratio of the silicon compound (C) to the organoaluminum compound (B).

[0040] The propylene homopolymer according to this embodiment is obtained using an olefin polymerization catalyst obtained by contacting an olefin polymerization solid catalyst component (A), an organoaluminum compound (B), and a silicon compound (C).

[0041] The solid catalyst component (A) for olefin polymerization contains a titanium atom, a magnesium atom, a halogen atom and an internal electron donor.

[0042] The solid catalyst component (A) for olefin polymerization means a substance that exists as a solid component at least in toluene and that constitutes an olefin polymerization catalyst when brought into contact with an organoaluminum compound and an external electron donor.

[0043] A part or all of the titanium atoms in the solid catalyst component (A) for olefin polymerization are derived from a titanium halide compound. A part or all of the halogen atoms in the solid catalyst component for olefin polymerization are derived from a titanium halide compound.

[0044] Examples of the titanium halide compound include titanium tetrahalide, monoalkoxytitanium trihalide, dialkoxytitanium dihalide, and trialkoxytitanium monohalide. The titanium halide compound is preferably titanium tetrahalide or monoalkoxytitanium trihalide, and more preferably titanium tetrahalide. The titanium halide compound may be used alone or in combination of two or more.

[0045] A part or all of the magnesium atoms in the solid catalyst component (A) for olefin polymerization are derived from a magnesium compound, and a part of the halogen atoms in the solid catalyst component (A) for olefin polymerization may be derived from a magnesium compound.

[0046] Examples of the magnesium compound include dialkyl magnesium, magnesium dialkoxide, alkyl magnesium halide, alkoxy magnesium halide, aryloxy magnesium halide, and magnesium halide. The magnesium compound is preferably magnesium halide or magnesium dialkoxide. The magnesium compounds may be used alone or in combination of two or more.

[0047] The internal electron donor refers to an organic compound capable of donating electron pairs to one or more metal atoms contained in the solid catalyst component for olefin polymerization. Examples of the internal electron donor include monoester compounds, dicarboxylic acid ester compounds, diol diester compounds, β-alkoxy ester compounds, and diether compounds.

[0048] The monoester compound refers to an organic compound having one ester bond (—CO—O—) in the molecule. The monoester compound is preferably an aromatic carboxylic acid ester compound or an aliphatic carboxylic acid ester compound.

[0049] The dicarboxylic acid ester compound is a compound having two ester bonds (—CO—O—) in the molecule, and has a structure in which two carboxyl groups of a dicarboxylic acid are esterified with a monohydric alcohol. The dicarboxylic acid ester compound is preferably an aromatic dicarboxylic acid ester compound or an aliphatic dicarboxylic acid ester compound.

[0050] The β-alkoxy ester compound means a compound having an alkoxycarbonyl group and an alkoxy group at the β-position of the alkoxycarbonyl group.

[0051] The diether compound means a compound having two ether bonds in the molecule.

[0052] Further examples include the internal electron donors described in JP-A-2011-246699.

[0053] From the viewpoint of obtaining excellent uniform stretchability, the internal electron donor is at least one selected from the group consisting of monoester compounds, diester compounds, diol diester compounds, β-alkoxy ester compounds, and diether compounds, and preferably at least one selected from the group consisting of diol diester compounds, β-alkoxy ester compounds, and diether compounds. The internal electron donors may be used alone or in combination of two or more.

[0054] The organoaluminum compound (B) is a compound having one or more carbon-aluminum bonds, and specific examples thereof include the compounds described in JP-A-10-212319. The organoaluminum compound is preferably a trialkylaluminum, a mixture of a trialkylaluminum and a dialkylaluminum halide, or an alkylalumoxane, and more preferably triethylaluminum, triisobutylaluminum, a mixture of triethylaluminum and diethylaluminum chloride, or tetraethyldialumoxane.

[0055] The silicon compound (C) is represented by the following formula (i) or (ii): １ ｎ Si(OR ２ ) ４－ｎ ... (i) (R １ is a hydrocarbyl group having 1 to 20 carbon atoms or a hydrogen atom. ２ is a hydrocarbyl group having 1 to 20 carbon atoms, and n is an integer satisfying the condition 0≦n≦2. １ If there are multiple １ may be the same or different. ２ If there are multiple ２ may be the same or different.) R ３ ｍ Si(NR ４ R ５ ) ４－ｍ ... (ii) (R ３ is a hydrocarbyl group having 1 to 20 carbon atoms, an alkoxy group, or a hydrogen atom. ４ and R ５ is a hydrocarbyl group having 1 to 12 carbon atoms or a hydrogen atom, and m is an integer satisfying the condition 0≦m≦4. ３ If there are multiple ３ may be the same or different. ４ If there are multiple ４ may be the same or different. ５ If there are multiple ５ may be the same or different.)

[0056] R in the above formula (i) １ and R ２ Examples of the hydrocarbyl group in R include an alkyl group, an aralkyl group, an aryl group, and an alkenyl group. １ and R ２ Examples of the alkyl group of R include linear alkyl groups such as methyl, ethyl, n-propyl, n-butyl, n-pentyl, n-hexyl, n-heptyl, and n-octyl groups; branched alkyl groups such as isopropyl, isobutyl, t-butyl, isopentyl, neopentyl, and 2-ethylhexyl groups; and cyclic alkyl groups such as cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, and cyclooctyl groups. １ and R ２ The alkyl group in R is preferably a linear, branched or cyclic alkyl group having 1 to 20 carbon atoms. １ and R ２ Examples of the aralkyl group of R include a benzyl group and a phenethyl group. １ and R ２ The aralkyl group of R is preferably an aralkyl group having 7 to 20 carbon atoms. １ and R ２ The aryl group of R includes a phenyl group, a tolyl group, and a xylyl group. １ and R ２ The aryl group in R is preferably an aryl group having 6 to 20 carbon atoms. １ and R ２ Examples of the alkenyl group in R include linear alkenyl groups such as vinyl, allyl, 3-butenyl, and 5-hexenyl groups; branched alkenyl groups such as isobutenyl and 5-methyl-3-pentenyl groups; and cyclic alkenyl groups such as 2-cyclohexenyl and 3-cyclohexenyl groups. １ and R ２ The alkenyl group is preferably an alkenyl group having 2 to 10 carbon atoms.

[0057] Specific examples of the silicon compound (C) represented by the above formula (i) include phenyltrimethoxysilane, methyltriethoxysilane, ethyltriethoxysilane, n-propyltriethoxysilane, isobutyltriethoxysilane, vinyltriethoxysilane, sec-butyltriethoxysilane, cyclohexyltriethoxysilane, cyclopentyltriethoxysilane, benzyltriethoxysilane, dicyclopentyldimethoxysilane, cyclohexylethyldimethoxysilane, and n-propylmethyldimethoxysilane.

[0058] R in the above formula (ii) ３ The hydrocarbyl group in the above formula (i) is １ and the like.

[0059] R in the above formula (ii) ３ Examples of the alkoxy group include linear alkoxy groups such as methoxy, ethoxy, n-propoxy, n-butoxy, n-pentyloxy, and n-hexyloxy groups; branched alkoxy groups such as isopropoxy, isobutoxy, t-butoxy, isopentyloxy, and neopentyloxy groups; and cyclic alkoxy groups such as cyclopropoxy, cyclobutoxy, cyclopentyloxy, and cyclohexyloxy groups.

[0060] R in the above formula (ii) ４ and R ５ Examples of the hydrocarbyl group in R include an alkyl group and an alkenyl group. ４ and R ５ Examples of the alkyl group of R include linear alkyl groups such as methyl, ethyl, n-propyl, n-butyl, n-pentyl, and n-hexyl groups; branched alkyl groups such as isopropyl, isobutyl, t-butyl, isopentyl, and neopentyl groups; and cyclic alkyl groups such as cyclopropyl, cyclobutyl, cyclopentyl, and cyclohexyl groups. ４ and R ５ The alkyl group in R is preferably a linear alkyl group having 1 to 6 carbon atoms. ４ and R５ Examples of the alkenyl group in R include linear alkenyl groups such as vinyl, allyl, 3-butenyl, and 5-hexenyl groups; branched alkenyl groups such as isobutenyl and 5-methyl-3-pentenyl groups; and cyclic alkenyl groups such as 2-cyclohexenyl and 3-cyclohexenyl groups. ４ and R ５ The alkenyl group is preferably a linear alkenyl group having 2 to 6 carbon atoms, and particularly preferably a methyl group or an ethyl group.

[0061] Specific examples of the silicon compound (C) represented by the above formula (ii) include bis(ethylamino)dicyclopentylsilane, bis(ethylamino)diisopropylsilane, and bis(methylamino)di-t-butylsilane. Further examples include the amino silicon compounds described in WO2006 / 129773.

[0062] From the viewpoint of obtaining more excellent uniform stretchability, R １ or R ３ preferably contains one or more branched hydrocarbon groups or cyclic hydrocarbon groups, more preferably contains at least one selected from the group consisting of a cyclohexyl group, a cyclopentyl group, a t-butyl group, a secondary isobutyl group, and an isopropyl group, and even more preferably contains at least one of a cyclopentyl group and a cyclohexyl group.

[0063] The method for contacting the solid catalyst component (A) for olefin polymerization, the organoaluminum compound (B), and the silicon compound (C) is not particularly limited, as long as an olefin polymerization catalyst is produced. The contact is carried out in the presence or absence of a solvent. The contact mixture may be fed to a polymerization vessel, or each component may be fed separately to a polymerization vessel and contacted in the polymerization vessel, or a contact mixture of any two components and the remaining component may be fed separately to a polymerization vessel and contacted in the polymerization vessel.

[0064] The amount of the organoaluminum compound (B) used is usually 0.01 to 1000 μmol, preferably 0.1 to 500 μmol, per mg of the solid catalyst component (A) for olefin polymerization.

[0065] The amount of the silicon compound (C) used is usually 0.0001 to 0.80 μmol, preferably 0.001 to 0.50 μmol, more preferably 0.01 to 0.30 μmol, per mg of the solid catalyst component (A) for olefin polymerization.

[0066] The molar ratio of the organoaluminum compound (B) to the silicon compound (C) is 100:1 to 1000:1, preferably 200:1 to 900:1, and more preferably 300:1 to 800:1.

[0067] The propylene homopolymer according to this embodiment can obtain excellent uniform stretchability by having the molar ratio of the silicon compound (C) to the organoaluminum compound (B) within the above range.

[0068] As raw materials for the propylene homopolymer, for example, monomers such as fossil resource-derived monomers (ethylene, propylene, 1-butene, 1-hexene, etc.), plant-derived monomers (ethylene, propylene, 1-butene, 1-hexene, etc.), and chemically recycled monomers (ethylene, propylene, 1-butene, 1-hexene, etc.) can be used, and two or more of these may be used in combination. Specific examples of monomer combinations include fossil resource-derived ethylene / plant-derived ethylene / chemically recycled ethylene, fossil resource-derived ethylene / plant-derived ethylene / chemically recycled ethylene / fossil resource-derived 1-butene / plant-derived 1-butene / chemically recycled 1-butene, fossil resource-derived ethylene / plant-derived ethylene / chemically recycled ethylene / fossil resource-derived 1-hexene / plant-derived 1-hexene / chemically recycled 1-hexene, fossil resource-derived propylene / plant-derived propylene / chemically recycled propylene, fossil resource-derived propylene / plant-derived propylene / chemically recycled propylene / fossil resource-derived ethylene / plant-derived ethylene / chemically recycled ethylene, fossil resource-derived propylene / plant-derived propylene / chemically recycled propylene / fossil resource-derived 1-butene / plant-derived 1-butene / chemically recycled 1-butene, and the like.

[0069] Fossil resource-derived monomers are derived from carbon found in underground resources such as petroleum, coal, and natural gas, and generally contain almost no carbon-14 (C). Methods for producing fossil resource-derived monomers include known methods, such as cracking petroleum-derived naphtha, ethane, etc., and methods for producing olefins by dehydrogenation of ethane, propane, etc.

[0070] Plant-derived monomers are derived from carbon circulating on the earth's surface as plants and animals, and generally contain a certain proportion of carbon-14 (14C). Examples of methods for producing plant-derived monomers include known methods, such as cracking bionaphtha, vegetable oil, animal oil, etc., dehydrogenation of biopropane, methods of separating alcohol from fermented products such as sugars extracted from plant materials such as sugarcane and corn, and then subjecting the alcohol to a dehydration reaction (JP-A-2010-511634, JP-A-2011-506628, JP-A-2013-503647, etc.), and methods of subjecting ethylene obtained from plant-derived ethanol to a metathesis reaction with n-butene (WO 2007 / 055361, etc.).

[0071] Chemically recycled monomers are derived from carbon generated by the decomposition, combustion, etc. of waste, and their carbon-14 (14C) content varies depending on the waste. Methods for producing chemically recycled monomers include known methods, such as a method of thermally decomposing waste plastics (JP Patent Publication No. 2017-512246, etc.), a method of cracking waste vegetable oil, waste animal oil, etc. (JP Patent Publication No. 2018-522087, etc.), and a method of gasifying, converting to alcohol, and dehydrating waste such as food waste, biomass waste, food waste, waste oil, waste wood, waste paper, and waste plastic (JP Patent Publication No. 2019-167424, WO2021 / 006245, etc.).

[0072] When two or more of fossil resource-derived olefins, plant-derived olefins, and chemically recycled olefins are used, olefins produced individually may be mixed and used in combinations such as fossil resource-derived olefins / plant-derived olefins, fossil resource-derived olefins / chemically recycled olefins, plant-derived olefins / chemically recycled olefins, or fossil resource-derived olefins / plant-derived olefins / chemically recycled olefins. Furthermore, a mixture of the above olefin combinations may be produced by using a mixture of combinations such as fossil resource-derived compound / plant-derived compound, fossil resource-derived compound / chemically recycled compound, plant-derived compound / chemically recycled compound, or fossil resource-derived compound / plant-derived compound / chemically recycled compound as a raw material or production intermediate in the olefin production process.

[0073] From the viewpoint of reducing the environmental load, the carbon-14 (14C) concentration of the propylene homopolymer is preferably 0.2 pMC(%) or more, more preferably 0.5 pMC(%) or more, even more preferably 1.0 pMC(%) or more, still more preferably 5.0 pMC(%) or more, and particularly preferably 10.0 pMC(%) or more. From the viewpoint of cost, it is preferably 99.0 pMC(%) or less, more preferably 95 pMC(%) or less, even more preferably 90.0 pMC(%) or less, still more preferably 70.0 pMC(%) or less, and particularly preferably 50.0 pMC(%) or less.

[0074] The carbon-14 (14C) concentration of the propylene homopolymer can be adjusted by changing the ratio of the fossil resource-derived olefin, plant-derived olefin, and chemically recycled olefin used in the production of the polyolefin resin.

[0075] [Pellets] The pellets according to this embodiment contain a propylene homopolymer and an antioxidant.

[0076] The half-width (H) of the melting peak of the pellet according to this embodiment measured using a differential scanning calorimeter (DSC) ｗ ) is 7.7°C or higher, preferably 8.0°C or higher and 20.0°C or lower, and more preferably 8.0°C or higher and 15.0°C or lower.

[0077] The half-width of the melting peak of the pellet (H ｗ ) is the half-width (H ｗ ) can be measured by the same method as the measurement method for

[0078] The pellets according to this embodiment have a melting peak half-width (H ｗ ) is within the above range, excellent uniform stretchability can be obtained.

[0079] The half-width (H) of the melting peak measured using a differential scanning calorimeter (DSC) of the pellet ｗ) is the half-width (H ) of the melting peak of the propylene homopolymer measured using a differential scanning calorimeter (DSC). ｗ ) can be adjusted by the same method as for adjusting the above.

[0080] The melting point (T ｍ ) is 159.0°C or higher and 170.0°C or lower, preferably 159.0°C or higher and 168.0°C or lower, and more preferably 159.5°C or higher and 165.0°C or lower.

[0081] The melting point of the pellet (T ｍ ) is the melting point of propylene homopolymer (T ｍ ) can be measured by the same method as the measurement method for

[0082] The pellets according to this embodiment have a melting point (T ｍ ) is within the above range, excellent uniform stretchability can be obtained.

[0083] The melting point of the pellet (T ｍ ) is the melting point of propylene homopolymer (T ｍ ) can be adjusted by the same method as for adjusting the above.

[0084] The molecular weight distribution (Mw / Mn) of the pellets according to this embodiment is 4.1 or more, preferably 4.5 or more and 10.0 or less, and more preferably 4.5 or more and 8.0 or less.

[0085] The molecular weight distribution (Mw / Mn) of the pellets can be measured by the same method as that for measuring the molecular weight distribution (Mw / Mn) of a propylene homopolymer.

[0086] The pellets according to this embodiment have a molecular weight distribution (Mw / Mn) within the above range, so that excellent uniform stretchability can be obtained.

[0087] The molecular weight distribution (Mw / Mn) of the pellets can be adjusted by the same method as that for adjusting the molecular weight distribution (Mw / Mn) of the propylene homopolymer.

[0088] The isothermal crystallization time (T １／２) is preferably 100.0 s or less, more preferably 30.0 s or more and 95.0 s or less, and even more preferably 60.0 s or more and 90.0 s or less.

[0089] The isothermal crystallization time (T １／２ ) is the isothermal crystallization time (T １／２ ) can be measured by the same method as the measurement method for

[0090] The pellets according to this embodiment have an isothermal crystallization time (T １／２ ) is within the above range, more excellent uniform stretchability can be obtained.

[0091] The isothermal crystallization time (T １／２ ) is the isothermal crystallization time (T １／２ ) can be adjusted by the same method as for adjusting the above.

[0092] The propylene homopolymer in the pellets according to this embodiment can be the propylene homopolymer described above. That is, the further detailed description of the propylene homopolymer in the section [Pellets] is the same as that described in the section [Propylene homopolymer]. Therefore, the detailed description will not be repeated in the section [Pellets].

[0093] Examples of the antioxidant in the pellet according to the present embodiment include phenol-based antioxidants, phosphorus-based antioxidants, etc. One type of antioxidant may be used alone, or two or more types may be used in combination.

[0094] Examples of phenolic antioxidants include 2,6-di-t-butyl-4-methylphenol (BHT), n-octadecyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate (trade name: IRGANOX 1076, manufactured by BASF Japan Ltd.), pentaerythrityl-tetrakis[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate] (trade name: IRGANOX 1010, manufactured by BASF Japan Ltd.), 1,3,5-tris(3,5-di-t-butyl- 4-hydroxybenzyl) isocyanurate (trade name: IRGANOX3114, manufactured by BASF Japan Ltd.), 1,3,5-trimethyl-2,4,6-tris(3,5-di-t-butyl-4-hydroxybenzyl)benzene, 3,9-bis[2-{3-(3-t-butyl-4-hydroxy-5-methylphenyl)propionyloxy}-1,1-dimethylethyl]-2,4,8,10-tetraoxaspiro[5.5]undecane (trade name: Sumilizer GA80, manufactured by Sumitomo Chemical Co., Ltd.), and the like.

[0095] Examples of phosphorus-based antioxidants include distearyl pentaerythritol diphosphite, tris(2,4-di-t-butylphenyl)phosphite (trade name: IRGAFOS168, manufactured by BASF Japan Ltd.), bis(2,4-di-t-butylphenyl)pentaerythritol diphosphite, tetrakis(2,4-di-t-butylphenyl)-4,4′-biphenylene diphosphite, bis(2-t-butyl-4-methylphenyl)pentaerythritol diphosphite, and 2,4,8,10-tetra-t-butyl-6-[3-(3-methyl-4-hydroxy-5-t-butylphenyl)propoxy]dibenzo[d,f][1,3,2]dioxaphosphepine (trade name: Sumilizer GP, manufactured by Sumitomo Chemical Co., Ltd.).

[0096] In the pellets according to the present embodiment, the content of the antioxidant is preferably 0.0001% by mass or more and 10% by mass or less, more preferably 0.001% by mass or more and 5% by mass or less, and even more preferably 0.01% by mass or more and 1% by mass or less, relative to 100% by mass of the propylene homopolymer. When two or more kinds of antioxidants are used, the content of the antioxidants is the total value of the contents of these antioxidants.

[0097] The pellets according to this embodiment may further contain a neutralizing agent. Examples of the neutralizing agent include calcium stearate, synthetic hydrotalcite (trade name: DHT-4C, manufactured by Kyowa Chemical Industry Co., Ltd.), alkaline earth metal oxides, and alkaline earth metal hydroxides. The neutralizing agents may be used alone or in combination of two or more.

[0098] In the pellets according to this embodiment, the content of the neutralizing agent may be 0.0001% by mass or more and 10% by mass or less, or 0.001% by mass or more and 1% by mass or less, relative to 100% by mass of the propylene homopolymer.

[0099] The pellet according to the present embodiment may further contain optional components, such as an ultraviolet absorber, a nucleating agent, a lubricant, an antistatic agent, an antiblocking agent, a processing aid, an organic peroxide, a colorant (inorganic pigment, organic pigment, pigment dispersant, etc.), a plasticizer, a flame retardant, a crosslinking agent, a crosslinking aid, a brightness enhancer, an antibacterial agent, a light diffusing agent, and a light stabilizer.

[0100] [Molded Article] The propylene homopolymer may be molded into a molded article. The pellets may be molded into a molded article. Examples of the molded article include a non-stretched sheet, a uniaxially stretched film, and a biaxially stretched film.

[0101] The unstretched sheet can be obtained, for example, by heating and melting the above-mentioned propylene homopolymer using an extruder and extruding it onto a cooling roll through a T-die.

[0102] The uniaxially stretched film can be obtained, for example, by stretching the unstretched sheet in the MD direction by 6 to 10 times, preferably 8 to 10 times, using a stretching roll.

[0103] A biaxially stretched film can be obtained, for example, by stretching the uniaxially stretched film in the TD direction in a heating furnace using two rows of chucks aligned along the MD direction to a stretching ratio of 4 to 20 times, preferably 4 to 10 times. When stretching the uniaxially stretched film in the TD direction, both side edges in the TD direction of the uniaxially stretched sheet are gripped with two rows of chucks aligned along the MD direction, and the uniaxially stretched sheet is stretched in the TD direction at the above-mentioned stretching ratio in a heating furnace equipped with a preheating section, a stretching section, and a heat treatment section, thereby obtaining a biaxially stretched film.

[0104] The unstretched sheet according to this embodiment contains the above-mentioned propylene homopolymer, and is preferably made of the above-mentioned propylene homopolymer.

[0105] The uniaxially stretched film according to this embodiment contains the above-mentioned propylene homopolymer, and preferably consists of the above-mentioned propylene homopolymer.

[0106] The biaxially stretched film according to this embodiment contains the above-mentioned propylene homopolymer, and preferably consists of the above-mentioned propylene homopolymer.

[0107] [Method for producing propylene homopolymer] The method for producing a propylene homopolymer according to this embodiment includes a step of homopolymerizing a propylene homopolymer in the presence of an olefin polymerization catalyst obtained by contacting an olefin polymerization solid catalyst component (A), an organoaluminum compound (B), and a silicon compound (C) (hereinafter also referred to as a "homopolymerization step").

[0108] The homopolymerization step may have a prepolymerization step as a first embodiment, a prepolymerization step and a first polymerization step as a second embodiment, or a prepolymerization step, a first polymerization step and a second polymerization step as a third embodiment.

[0109] In the prepolymerization step, the solid catalyst component for olefin polymerization (A), an organoaluminum compound (B), and a silicon compound (C) may be contacted with each other to obtain an olefin polymerization catalyst. In the prepolymerization step, propylene may be further contacted with the olefin polymerization catalyst to homopolymerize propylene.

[0110] The temperature in the prepolymerization step may be −10° C. or higher and 30° C. or lower. The set temperature of the reactor may be the temperature in the prepolymerization step.

[0111] The pressure in the prepolymerization step may be 0 MPaG or more and 0.6 MPaG or less.

[0112] In the first polymerization step and the second polymerization step, propylene may be homopolymerized by contacting it with an olefin polymerization catalyst.

[0113] The temperature of the first polymerization step may be 45° C. or higher and 70° C. or lower. The temperature of the second polymerization step may be 60° C. or higher and 90° C. or lower. The set temperature of the reactor may be the temperature of the first polymerization step or the temperature of the second polymerization step.

[0114] The pressure in the first polymerization step may be 2.5 MPaG or more and 3.5 MPaG or less. The pressure in the second polymerization step may be 1.7 MPaG or more and 2.2 MPaG or less.

[0115] In the method for producing a propylene homopolymer according to the present embodiment, a post-treatment step may be further carried out after the homopolymerization step. The post-treatment step may include a step of terminating the polymerization reaction (reaction termination step) and a drying step.

[0116] The method for terminating the polymerization reaction in the reaction termination step is not particularly limited, but may be, for example, a method of passing water vapor through the reaction mixture. In the method of passing water vapor through the reaction mixture, water vapor at a temperature of 50° C. or higher and 120° C. or lower may be used.

[0117] The drying method in the drying step is not particularly limited, but may be, for example, a method of passing nitrogen gas through the drying step, in which nitrogen gas at a temperature of 50° C. or higher and 120° C. or lower may be used.

[0118] In the method for producing a propylene homopolymer according to this embodiment, the solid catalyst component (A) for olefin polymerization contains a titanium atom, a magnesium atom, a halogen atom, and an internal electron donor.

[0119] In the method for producing a propylene homopolymer according to this embodiment, the internal electron donor is at least one selected from the group consisting of a monoester compound, a diester compound, a diol diester compound, a β-alkoxy ester compound, and a diether compound, preferably at least one selected from the group consisting of a diol diester compound, a β-alkoxy ester compound, and a diether compound, from the viewpoint of obtaining excellent uniform stretchability. The internal electron donors may be used alone or in combination of two or more.

[0120] In the method for producing a propylene homopolymer according to this embodiment, the silicon compound (C) is represented by the following formula (i) or (ii): １ ｎ Si(OR ２ ) ４－ｎ ... (i) (R １ is a hydrocarbyl group having 1 to 20 carbon atoms or a hydrogen atom. ２ is a hydrocarbyl group having 1 to 20 carbon atoms, and n is an integer satisfying the condition 0≦n≦2. １ If there are multiple １ may be the same or different. ２ If there are multiple ２ may be the same or different.) R ３ ｍ Si(NR ４ R ５ ) ４－ｍ ... (ii) (R ３ is a hydrocarbyl group having 1 to 20 carbon atoms, an alkoxy group, or a hydrogen atom. ４ and R ５ is a hydrocarbyl group having 1 to 12 carbon atoms or a hydrogen atom, and m is an integer satisfying the condition 0≦m≦4. ３ If there are multiple ３ may be the same or different.４ If there are multiple ４ may be the same or different. ５ If there are multiple ５ may be the same or different.)

[0121] In the method for producing a propylene homopolymer according to this embodiment, R １ or R ３ Preferably, the copolymer contains one or more branched hydrocarbon groups or cyclic hydrocarbon groups, from the viewpoint of obtaining better uniform stretchability.

[0122] In the method for producing a propylene homopolymer according to this embodiment, the molar ratio of the organoaluminum compound (B) to the silicon compound (C) is 100:1 to 1000:1, preferably 200:1 to 900:1, and more preferably 300:1 to 800:1.

[0123] Further detailed descriptions of the solid catalyst component for olefin polymerization (A), the organoaluminum compound (B), and the silicon compound (C) in the section [Method for producing propylene homopolymer] are the same as those explained in the section [Propylene homopolymer], and therefore, the detailed descriptions thereof will not be repeated in the section [Method for producing propylene homopolymer].

[0124] The present invention includes the following aspects: [1] A melting peak half-width (H ) measured using a differential scanning calorimeter (DSC) ｗ ) is 7.7°C or higher, and the melting point (T ｍ [2] The propylene homopolymer according to [1], having an isotactic pentad fraction of 0.950 or less. [3] The propylene homopolymer according to [1], having an isothermal crystallization time (T １／２[4] A non-stretched sheet comprising the propylene homopolymer according to any one of [1] to [3]. [5] A uniaxially stretched film comprising the propylene homopolymer according to any one of [1] to [3]. [6] A biaxially stretched film comprising the propylene homopolymer according to any one of [1] to [3]. [7] A method for producing a propylene homopolymer, comprising a step of homopolymerizing a propylene homopolymer in the presence of an olefin polymerization catalyst obtained by contacting a solid catalyst component for olefin polymerization (A), an organoaluminum compound (B), and a silicon compound (C), wherein the solid catalyst component for olefin polymerization (A) contains a titanium atom, a magnesium atom, a halogen atom, and an internal electron donor, the internal electron donor is at least one selected from the group consisting of a monoester compound, a diester compound, a diol diester compound, a β-alkoxy ester compound, and a diether compound, the silicon compound (C) is represented by the following formula (i) or (ii), and the molar ratio of the organoaluminum compound (B) to the silicon compound (C) is 100:1 to 1000:1. １ ｎ Si(OR ２ ) ４－ｎ ... (i) (R １ is a hydrocarbyl group having 1 to 20 carbon atoms or a hydrogen atom. ２ is a hydrocarbyl group having 1 to 20 carbon atoms, and n is an integer satisfying the condition 0≦n≦2. １ If there are multiple １ may be the same or different. ２ If there are multiple ２ may be the same or different.) R ３ ｍ Si(NR ４ R ５ ) ４－ｍ ... (ii) (R ３ is a hydrocarbyl group having 1 to 20 carbon atoms, an alkoxy group, or a hydrogen atom. ４ and R ５is a hydrocarbyl group having 1 to 12 carbon atoms or a hydrogen atom, and m is an integer satisfying the condition 0≦m≦4. ３ If there are multiple ３ may be the same or different. ４ If there are multiple ４ may be the same or different. ５ If there are multiple ５ may be the same or different.) [8] R in the silicon compound (C) １ or R ３ [9] The method for producing a propylene homopolymer according to [7] or [8], wherein the internal electron donor is at least one selected from the group consisting of a diol diester compound, a β-alkoxy ester compound, and a diether compound.

[10] A propylene homopolymer obtained by using an olefin polymerization catalyst obtained by contacting a solid catalyst component for olefin polymerization (A), an organoaluminum compound (B), and a silicon compound (C), wherein the solid catalyst component for olefin polymerization (A) contains a titanium atom, a magnesium atom, a halogen atom, and an internal electron donor, the internal electron donor is at least one selected from the group consisting of a monoester compound, a diester compound, a diol diester compound, a β-alkoxy ester compound, and a diether compound, the silicon compound (C) is represented by the following formula (i) or (ii), and the molar ratio of the organoaluminum compound (B) to the silicon compound (C) is 100:1 to 1000:1. １ ｎ Si(OR ２ ) ４－ｎ ... (i) (R １ is a hydrocarbyl group having 1 to 20 carbon atoms or a hydrogen atom. ２ is a hydrocarbyl group having 1 to 20 carbon atoms, and n is an integer satisfying the condition 0≦n≦2. １ If there are multiple １ may be the same or different.２ If there are multiple ２ may be the same or different.) R ３ ｍ Si(NR ４ R ５ ) ４－ｍ ... (ii) (R ３ is a hydrocarbyl group having 1 to 20 carbon atoms, an alkoxy group, or a hydrogen atom. ４ and R ５ is a hydrocarbyl group having 1 to 12 carbon atoms or a hydrogen atom, and m is an integer satisfying the condition 0≦m≦4. ３ If there are multiple ３ may be the same or different. ４ If there are multiple ４ may be the same or different. ５ If there are multiple ５ may be the same or different.)

[11] R in the silicon compound (C) １ or R ３

[12] The propylene homopolymer according to

[10] or

[11] , wherein the internal electron donor is at least one selected from the group consisting of a diol diester compound, a β-alkoxy ester compound, and a diether compound.

[13] A propylene homopolymer comprising a propylene homopolymer and an antioxidant, wherein the half width of a melting peak (H ｗ ) is 7.7°C or higher, and the melting point (T ｍ

[14] The isothermal crystallization time (T) measured at 120°C is 159.0°C or more and 170.0°C or less, and the molecular weight distribution (Mw / Mn) is 4.1 or more. １／２ ) is 100.0 s or less.

[0125] The propylene homopolymer, unstretched sheet, uniaxially stretched film, biaxially stretched film, method for producing a propylene homopolymer, and pellets according to the present invention are not limited to the above-described embodiments, and various modifications are possible without departing from the gist of the present invention. Furthermore, the configurations, methods, etc. of embodiments other than those described above may be arbitrarily adopted and combined, and the configurations, methods, etc. of one embodiment described above may be applied to the configurations, methods, etc. of other embodiments described above.

[0126] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples. The measured values ​​of each item in the detailed description of the invention, examples, and comparative examples were measured by the following methods.

[0127] (1) Half-width of melting peak (H ｗ , unit: ° C.) Half width of melting peak (H ｗ ) was measured by differential scanning calorimetry. Pellets of propylene homopolymer were preheated using a heat press at 230 ° C for 5 minutes, pressed at 230 ° C for 5 minutes at a pressure of 5 MPa, and cooled at 25 ° C to 27 ° C for 5 minutes to produce a pressed sheet with a thickness of 0.2 mm. 5 mg of the pressed sheet sample was sealed in an aluminum pan, and using a TA Instruments DSC D250 or TA Instruments DSC Q2000, the sample was heated to 230 ° C under a nitrogen atmosphere (first heating), held at 230 ° C for 5 minutes, cooled from 230 ° C to 0 ° C at 5 ° C / min, and heated from 0 ° C to 230 ° C at 5 ° C / min (second heating). A corrected melting endothermic curve was obtained by subtracting the straight line connecting the 20 ° C point and the 200 ° C point as the baseline from the melting endothermic curve obtained in the second heating. The peak width at the midpoint of the height from the X axis to the maximum peak top of the corrected melting endothermic curve is called the half-width of the melting peak (H ｗ The temperature was corrected by setting the melting point of indium at 156.6°C and the heat of fusion of indium at 28.71 J / K. In the above measurement method, pellets of propylene homopolymer are used, and the half width (H ｗ ) is substantially the same as the measured value when the propylene homopolymer itself is measured.

[0128] (2) Melting point (T ｍ , unit: °C) Melting point (T ｍ ) was measured by differential scanning calorimetry. Pellets of propylene homopolymer were preheated using a heat press at 230 ° C for 5 minutes, pressed at 230 ° C for 5 minutes at a pressure of 5 MPa, and cooled at 25 ° C to 27 ° C for 5 minutes to produce a pressed sheet with a thickness of 0.2 mm. 5 mg of the pressed sheet sample was sealed in an aluminum pan, and using a TA Instruments DSC D250 or TA Instruments DSC Q2000, the sample was heated to 230 ° C under a nitrogen atmosphere (first heating), held at 230 ° C for 5 minutes, cooled from 230 ° C to 0 ° C at 5 ° C / min, and heated from 0 ° C to 230 ° C at 5 ° C / min (second heating). TA Universal Analysis (TA Instruments) was used as the analysis software. The temperature of the maximum peak of the melting endothermic curve obtained in the second heating is the melting point (T ｍ The temperature was corrected by setting the melting point of indium at 156.6°C and the heat of fusion of indium at 28.71 J / K. In the above measurement method, pellets of propylene homopolymer are used, and the melting point (T ｍ ) is substantially the same as the measured value when the propylene homopolymer itself is measured.

[0129] (3) Molecular weight distribution (Mw / Mn) The molecular weight distribution of propylene homopolymer was measured using gel permeation chromatography (GPC) under the following conditions. Peaks were designated by defining the baseline on the chromatogram based on the description of ISO 16014-1. (GPC apparatus and software) Apparatus: HLC-8321GPC / HT (manufactured by Tosoh Corporation) Software: HLC-8321 GPC / HT Program Version 2.02 (manufactured by Tosoh Corporation) (Measurement conditions) GPC column: TSKgel GMHHR-H(S)HT 7.8 mm I.D. × 300 mm (Tosoh Corporation), 3 columns; Mobile phase: dibutylhydroxytoluene (BHT) added to orthodichlorobenzene (Fujifilm Wako Pure Chemical Industries, Ltd., special grade) to a BHT concentration of 0.1 g / 100 mL. Flow rate: 1 mL / min; Column oven temperature: 140°C; Autosampler temperature: 140°C; System oven temperature: 40°C; Detection: Refractive index detector (RID); RID cell temperature: 140°C; Sample solution injection volume: 300 μL (Sample solution preparation conditions): A BHT-containing orthodichlorobenzene solution of the same composition as the mobile phase was used. Sample solution concentration: 1 mg / mL Dissolution conditions: 5 mg of sample was sealed in a 1000 mesh SUS wire mesh bag, and the wire mesh bag containing propylene homopolymer pellets as a sample was placed in a test tube. 5 mL of solvent was added to the test tube, the test tube was covered with aluminum foil, and the test tube was placed in an automatic dissolution shaker DF-8020 (manufactured by Tosoh Corporation) and stirred at a stirring rate of 60 reciprocations per minute at 140°C for 120 minutes. (Analysis method) Standard polystyrene (manufactured by Tosoh Corporation) was weighed out as a standard substance for GPC column calibration in the combinations shown in Table 2, and 5 mL of a BHT-containing orthodichlorobenzene solution with the same composition as the mobile phase was added. The solution was allowed to stand at room temperature for 120 minutes to dissolve.

[0130]

[0131] Using a calibration curve obtained from a standard substance, the polystyrene-equivalent average molecular chain lengths An and Aw of the propylene homopolymer were calculated. The polystyrene-equivalent average molecular chain lengths were each multiplied by the polypropylene Q factor of 26.4 to determine the polypropylene-equivalent average molecular weights (number average molecular weight (Mn) and weight average molecular weight (Mw)). As an index of molecular weight distribution, the ratio (Mw / Mn) of the number average molecular weight (Mn) to the weight average molecular weight (Mw) was calculated. Note that, although pellets of the propylene homopolymer are used in the above measurement method, the molecular weight distribution obtained by the above measurement method is substantially the same as the measured value when the propylene homopolymer itself is measured.

[0132] (4) Isotactic pentad fraction ([mmmm]) The isotactic pentad fraction (hereinafter also referred to as [mmmm]) of a propylene homopolymer is determined under the following conditions: １３ Measurement was performed by C-NMR. The assignment of the NMR absorption peaks of the propylene homopolymer was performed according to the method published by A. Zambelli et al. (Macromolecules, Vol. 8, p. 687, 1975). ・Model: Bruker AVANCE 600 ・Probe: 10 mm cryoprobe ・Measurement temperature: 135°C ・Pulse repetition time: 4 seconds ・Pulse width: 45° ・Number of accumulations: 256

[0133] (5) Isothermal crystallization time (T １／２ , unit: s) The isothermal crystallization time of the propylene homopolymer was measured using a differential scanning calorimeter (PerkinElmer DSC DSC8500). A 10 mg sample was placed in a nitrogen atmosphere and isothermal crystallization was carried out at a crystallization temperature of 120°C. The peak-top time of the peak of the obtained endothermic curve (1 / 2 isothermal crystallization time) was taken as the isothermal crystallization time. A shorter isothermal crystallization time indicates a faster crystallization rate. Note that although pellets of the propylene homopolymer are used in the above measurement method, the isothermal crystallization time obtained by the above measurement method is substantially the same as the measured value when the propylene homopolymer itself is measured.

[0134] Example 1: 1.66 L of n-hexane, which had been thoroughly dehydrated and degassed, 49.8 mmol of triethylaluminum (hexane solution), and 2.5 mmol of cyclohexylethyldimethoxysilane (hexane solution) were charged into a 2 L internal volume SUS autoclave equipped with a stirrer. Then, 19.9 g of a YC-100 series catalyst (a solid catalyst component for olefin polymerization containing titanium atoms, magnesium atoms, halogen atoms, and an internal electron donor) manufactured by Toho Titanium Co., Ltd. was further added, and 10 g of propylene was continuously fed over 30 minutes while maintaining the temperature inside the autoclave at about 3 to 10°C, thereby carrying out prepolymerization. The slurry obtained by prepolymerization was then transferred to a 160 L internal volume SUS autoclave equipped with a stirrer, and 131.0 L of fully purified liquid butane was added to form a slurry of prepolymerized catalyst components, which was then stored at a temperature of 10°C or below.

[0135] Propylene homopolymerization was carried out using a 163 L stirred vessel-type slurry polymerization reactor (hereinafter referred to as the "first reactor"). Specifically, the liquid level in the first reactor was set to 40 L, and polymerization was carried out by continuously feeding propylene, hydrogen, triethylaluminum, dicyclopentyldimethoxysilane, and the slurry of the prepolymerized catalyst component prepared above into the first reactor. The reaction conditions were as follows: polymerization temperature: 60°C, pressure: 3.03 MPaG, propylene feed rate: 50.0 kg / h, hydrogen feed rate: 21.0 NL / h, triethylaluminum feed rate: 35.0 mmol / h (hexane solution), dicyclopentyldimethoxysilane feed rate: 0.0552 mmol / h (hexane solution), and prepolymerized catalyst component slurry feed rate (solid catalyst component equivalent): 0.590 g / h. The amount of the propylene homopolymer component continuously discharged from the first reactor was 1.28 kg / hour. The obtained slurry containing the propylene homopolymer component was continuously transferred to a reactor to be used in the next step without being deactivated.

[0136] Internal volume 1.4m ３Propylene homopolymerization was carried out using a gas-phase fluidized bed reactor equipped with a stirrer (hereinafter referred to as the "second reactor"). A slurry containing a propylene homopolymer component continuously discharged from the first reactor was continuously polymerized under the following conditions: fluidized bed propylene homopolymer material load: 34.7 kg; polymerization temperature: 88°C; polymerization pressure: 1.95 MPaG; gas superficial velocity inside the second reactor: 0.215 m / sec; effective hydrogen concentration in the gas phase (hydrogen concentration / (hydrogen concentration + propylene concentration)): 0.18 mol%; and propylene concentration: 90.9 mol%. The amount of propylene homopolymer material continuously discharged from the second reactor was 17.0 kg / hr. The obtained propylene homopolymer material was continuously transferred to a post-treatment step. In the post-treatment step, the obtained propylene homopolymer material was continuously received while steam (H ) at 60°C was added. ２ 0≒100g / h) and nitrogen (flow rate 20 Nm ３ / hour) was passed through for 1 hour. Then, nitrogen (flow rate 20 Nm) at 60°C was passed through again. ３ / hour) was passed through the mixture for 1 hour and dried to obtain a propylene homopolymer.

[0137] 100 parts by mass of the obtained propylene homopolymer was blended with 0.01 parts by mass of DHT-4C (neutralizer, manufactured by Kyowa Chemical Industry Co., Ltd.), 0.15 parts by mass of IRGANOX1010 (antioxidant, manufactured by BASF Japan Ltd.), and 0.10 parts by mass of IRGAFOS168 (antioxidant, manufactured by BASF Japan Ltd.), followed by melt extrusion to obtain a pelletized propylene homopolymer composition. This propylene homopolymer composition was heated and melted at a resin temperature of 260°C using a T-die film-forming machine equipped with an extruder having a screw diameter of 65 mmφ, and extruded onto a cooling roll at 30°C to obtain an unstretched sheet made of the propylene homopolymer composition. The average thickness of the unstretched sheet in a range of ±50 mm from the center in the TD direction was 996 μm. The sheet was stretched using a tenter-type sequential biaxial stretching machine manufactured by Mitsubishi Heavy Industries, Ltd. A uniaxially stretched film was obtained by stretching the unstretched sheet 5 times in the MD direction using a stretching roll heated to 145 ° C (roll temperature). The TD side edges of the resulting uniaxially stretched film were gripped with two rows of chucks aligned along the MD direction, and the distance between the two rows of chucks was increased in the TD direction in a heating furnace heated to 157 ° C (first furnace temperature). The uniaxially stretched film was then stretched 8 times in the TD direction. Then, with the TD side edges of the stretched film gripped with two rows of chucks aligned along the MD direction, the distance between the two rows of chucks was narrowed in a heating furnace heated to 165 ° C (second furnace temperature), and the stretching in the TD direction was relaxed by 6.5%, resulting in a biaxially stretched film. The average thickness of the resulting biaxially stretched film in the TD direction within ±400 mm from the center was 20 μm.

[0138] (Example 2) A propylene homopolymer and a biaxially stretched film were obtained under the same conditions as in Example 1, except that the reaction conditions in the first reactor were as follows: pressure 3.09 MPaG, hydrogen supply rate 26.4 NL / h, triethylaluminum supply rate 35.1 mmol / h (hexane solution), dicyclopentyldimethoxysilane supply rate 0.0662 mmol / h (hexane solution), and prepolymerized catalyst component slurry supply rate (solid catalyst component equivalent): 0.608 g / h; and the reaction conditions in the second reactor were as follows: propylene homopolymer material retention amount in the fluidized bed 34.6 kg, effective hydrogen concentration in the gas phase 0.19 mol%, and propylene concentration 91.7 mol%. The amount of propylene homopolymer component continuously discharged from the first reactor was 2.20 kg / h, and the amount of propylene homopolymer material continuously discharged from the second reactor was 17.1 kg / h. The average thickness of the unstretched sheet in the range of ±50 mm from the center in the TD direction was 989 μm.

[0139] Example 3 A propylene homopolymer and a biaxially stretched film were obtained under the same conditions as in Example 1, except that the reaction conditions in the first reactor were: pressure 3.06 MPaG, hydrogen feed rate 25.1 NL / h, dicyclopentyldimethoxysilane feed rate 0.0671 mmol / h (hexane solution), and prepolymerized catalyst component slurry feed rate (solid catalyst component equivalent): 0.611 g / h. The reaction conditions in the second reactor were: propylene homopolymer material retention capacity in the fluidized bed 34.6 kg, and propylene concentration 91.7 mol%. The amount of propylene homopolymer component continuously discharged from the first reactor was 2.20 kg / h, and the amount of propylene homopolymer material continuously discharged from the second reactor was 18.9 kg / h. The average thickness of the unstretched sheet in the range of ±50 mm from the center in the TD direction was 980 μm.

[0140] Example 4 A propylene homopolymer and a biaxially stretched film were obtained under the same conditions as in Example 1, except that the reaction conditions in the first reactor were as follows: pressure: 3.08 MPaG, hydrogen supply rate: 31.8 NL / h, triethylaluminum supply rate: 35.2 mmol / h (hexane solution), dicyclopentyldimethoxysilane supply rate: 0.0677 mmol / h (hexane solution), prepolymerized catalyst component slurry supply rate (solid catalyst component equivalent): 0.565 g / h; and the reaction conditions in the second reactor were as follows: propylene homopolymer material holding amount in the fluidized bed: 34.6 kg, polymerization temperature: 70°C, effective hydrogen concentration in the gas phase: 0.22 mol%, and propylene concentration: 92.3 mol%. The amount of propylene homopolymer component continuously discharged from the first reactor was 1.30 kg / hr, and the amount of propylene homopolymer material continuously discharged from the second reactor was 15.9 kg / hr. The average thickness of the unstretched sheet in the range of ±50 mm from the center in the TD direction was 978 μm. The average thickness of the biaxially stretched film in the range of ±400 mm from the center in the TD direction was 21 μm.

[0141] (Example 5) A propylene homopolymer and a biaxially stretched film were obtained under the same conditions as in Example 1, except that the reaction conditions in the first reactor were as follows: pressure 3.11 MPaG, hydrogen supply rate 27.5 NL / h, triethylaluminum supply rate 32.7 mmol / h (hexane solution), dicyclopentyldimethoxysilane supply rate 0.0508 mmol / h (hexane solution), prepolymerized catalyst component slurry supply rate (solid catalyst component equivalent): 0.639 g / h, and the reaction conditions in the second reactor were as follows: propylene homopolymer material retention amount in the fluidized bed 34.6 kg, propylene concentration 92.4 mol%. The amount of propylene homopolymer component continuously discharged from the first reactor was 2.85 kg / h, and the amount of propylene homopolymer material continuously discharged from the second reactor was 16.9 kg / h. The average thickness of the unstretched sheet in the range of ±50 mm from the center in the TD direction was 1033 μm, and the average thickness of the biaxially stretched film in the range of ±400 mm from the center in the TD direction was 21 μm.

[0142] (Comparative Example 1) A propylene homopolymer and a biaxially stretched film were obtained under the same conditions as in Example 1, except that in an agitator-equipped SUS autoclave, the amount of n-hexane used was 1.67 L, the amount of triethylaluminum used was 50.0 mmol (hexane solution), the reaction conditions in the first reactor were a pressure of 2.77 MPaG, a hydrogen supply rate of 17.1 NL / h, a triethylaluminum supply rate of 43.1 mmol / h (hexane solution), n-propylmethyldimethoxysilane was used instead of dicyclopentyldimethoxysilane, and the n-propylmethyldimethoxysilane supply rate was 0.605 mmol / h (hexane solution), and a prepolymerized catalyst component slurry supply rate (solid catalyst component equivalent): 0.638 g / h, and the reaction conditions in the second reactor were a propylene homopolymer material retention amount in the fluidized bed of 79.7 kg, an effective hydrogen concentration in the gas phase of 0.11 mol%, and a propylene concentration of 92.2 mol%. The amount of propylene homopolymer component continuously discharged from the first reactor was 1.78 kg / hr, and the amount of propylene homopolymer material continuously discharged from the second reactor was 18.3 kg / hr. The average thickness of the unstretched sheet in the range of ±50 mm from the center in the TD direction was 996 μm. The average thickness of the biaxially stretched film in the range of ±400 mm from the center in the TD direction was 20 μm.

[0143] Comparative Example 2: 60% by mass of "FLX80E4" (melting point: 164°C) manufactured by Sumitomo Chemical Co., Ltd., 20% by mass of "D101" (melting point: 163°C) manufactured by Sumitomo Chemical Co., Ltd., and 20% by mass of "R101" (melting point: 164°C) manufactured by Sumitomo Chemical Co., Ltd. were mixed as propylene polymers, and then melt-extruded to obtain pelletized propylene polymer. This propylene polymer was heated and melted at a resin temperature of 260°C using a T-die film-forming machine equipped with an extruder with a screw diameter of 65 mmφ, and extruded onto a cooling roll at 30°C to obtain an unstretched sheet made of propylene polymer. The average thickness of the unstretched sheet in the range of ±50 mm from the center in the TD direction was 807 μm. The sheet was stretched using a tenter-type sequential biaxial stretching machine manufactured by Mitsubishi Heavy Industries, Ltd. The resulting unstretched sheet was stretched 5 times in the MD direction using a stretching roll heated to 145 ° C (roll temperature) to obtain a uniaxially stretched film. The TD side edges of the resulting uniaxially stretched film were gripped with two rows of chucks aligned along the MD direction, and the distance between the two rows of chucks was increased in the TD direction in a heating furnace heated to 157 ° C (first furnace temperature), thereby stretching the uniaxially stretched film 8 times in the TD direction. Then, with the TD side edges of the stretched film gripped with two rows of chucks aligned along the MD direction, the distance between the two rows of chucks was narrowed in a heating furnace heated to 165 ° C (second furnace temperature), and the stretching in the TD direction was relaxed by 6.5%, to obtain a biaxially stretched film. The average thickness of the resulting biaxially stretched film in the range of ±400 mm from the center in the TD direction was 12 μm.

[0144] (Evaluation of uniform stretchability (relative standard deviation, unit: %)) For the biaxially stretched films obtained in each example and comparative example, the film thickness in the TD direction was read using an NDC Pronet TDi infrared sensor thickness measurement system manufactured by NDC Technologies. The film thickness was read at intervals of approximately 2.54 mm width in the TD direction within a range of ±400 mm from the center of the biaxially stretched film. The relative standard deviation was calculated from the read film thicknesses and used as a measure of uniform stretchability. A smaller relative standard deviation indicates more uniform stretching processing and better uniform stretchability.

[0145] The evaluation results of the uniform stretchability of each example and each comparative example are shown in Table 3.

[0146]

[0147]

[0033] From Table 1, it can be seen that the biaxially stretched films using the propylene homopolymers of each Example satisfying all of the constituent requirements of the present invention have smaller relative standard deviations of film thickness than the biaxially stretched films of each Comparative Example, and therefore have relatively excellent uniform stretchability. In other words, according to the present invention, it is possible to provide a propylene homopolymer, an unstretched sheet, a uniaxially stretched film, a biaxially stretched film, a method for producing a propylene homopolymer, and pellets, all of which have relatively excellent uniform stretchability.

Claims

1. The half-width (H) of the melting peak measured using a differential scanning calorimeter (DSC) ｗ ) is 7.7°C or higher, and the melting point (T ｍ ) is 159.0°C or more and 170.0°C or less, and the molecular weight distribution (Mw / Mn) is 4.1 or more.

2. The propylene homopolymer according to claim 1, having an isotactic pentad fraction of 0.950 or less.

3. Isothermal crystallization time (T) measured at 120°C １／２ 2. The propylene homopolymer according to claim 1, wherein the tensile strength (Ts) of the propylene homopolymer is 100.0 s or less.

4. An unstretched sheet comprising the propylene homopolymer of claim 1.

5. A uniaxially stretched film comprising the propylene homopolymer of claim 1.

6. A biaxially oriented film comprising the propylene homopolymer of claim 1.

7. A method for producing a propylene homopolymer, comprising the step of homopolymerizing a propylene homopolymer in the presence of an olefin polymerization catalyst obtained by contacting a solid catalyst component for olefin polymerization (A), an organoaluminum compound (B), and a silicon compound (C), wherein the solid catalyst component for olefin polymerization (A) contains a titanium atom, a magnesium atom, a halogen atom, and an internal electron donor, the internal electron donor is at least one selected from the group consisting of a monoester compound, a diester compound, a diol diester compound, a β-alkoxy ester compound, and a diether compound, the silicon compound (C) is represented by the following formula (i) or (ii), and the molar ratio of the organoaluminum compound (B) to the silicon compound (C) is 100:1 to 1000:

1. １ ｎ Si(OR ２ ) ４－ｎ ... (i) (R １ is a hydrocarbyl group having 1 to 20 carbon atoms or a hydrogen atom. ２ is a hydrocarbyl group having 1 to 20 carbon atoms, and n is an integer satisfying the condition 0≦n≦2. １ If there are multiple １ may be the same or different. ２ If there are multiple ２ may be the same or different.) R ３ ｍ Si(NR ４ R ５ ) ４－ｍ ... (ii) (R ３ is a hydrocarbyl group having 1 to 20 carbon atoms, an alkoxy group, or a hydrogen atom. ４ and R ５ is a hydrocarbyl group having 1 to 12 carbon atoms or a hydrogen atom, and m is an integer satisfying the condition 0≦m≦4. ３ If there are multiple ３ may be the same or different. ４ If there are multiple ４ may be the same or different. ５ If there are multiple ５ may be the same or different.) 8. R in the silicon compound (C) １ or R ３ The method for producing a propylene homopolymer according to claim 7, wherein the propylene homopolymer contains one or more branched hydrocarbon groups or cyclic hydrocarbon groups.

9. The method for producing a propylene homopolymer according to claim 7, wherein the internal electron donor is at least one selected from the group consisting of a diol diester compound, a β-alkoxy ester compound, and a diether compound.

10. A propylene homopolymer obtained using an olefin polymerization catalyst obtained by contacting a solid catalyst component for olefin polymerization (A), an organoaluminum compound (B), and a silicon compound (C), wherein the solid catalyst component for olefin polymerization (A) contains a titanium atom, a magnesium atom, a halogen atom, and an internal electron donor, the internal electron donor being at least one selected from the group consisting of monoester compounds, diester compounds, diol diester compounds, β-alkoxyester compounds, and diether compounds, the silicon compound (C) being represented by the following formula (i) or (ii), and the molar ratio of the organoaluminum compound (B) to the silicon compound (C) being 100:1 to 1000:

1. R １ ｎ Si(OR ２ ) ４－ｎ ... (i) (R １ is a hydrocarbyl group having 1 to 20 carbon atoms or a hydrogen atom. ２ is a hydrocarbyl group having 1 to 20 carbon atoms, and n is an integer satisfying the condition 0≦n≦2. １ If there are multiple １ may be the same or different. ２ If there are multiple ２ may be the same or different.) R ３ ｍ Si(NR ４ R ５ ) ４－ｍ ... (ii) (R ３ is a hydrocarbyl group having 1 to 20 carbon atoms, an alkoxy group, or a hydrogen atom. ４ and R ５ is a hydrocarbyl group having 1 to 12 carbon atoms or a hydrogen atom, and m is an integer satisfying the condition 0≦m≦4. ３ If there are multiple ３ may be the same or different. ４ If there are multiple ４ may be the same or different. ５ If there are multiple ５ may be the same or different.) 11. R in the silicon compound (C) １ or R ３ The propylene homopolymer according to claim 10, wherein the propylene homopolymer comprises one or more branched hydrocarbon groups or cyclic hydrocarbon groups.

12. The propylene homopolymer according to claim 10, wherein the internal electron donor is at least one member selected from the group consisting of diol diester compounds, β-alkoxy ester compounds, and diether compounds.

13. A propylene homopolymer and an antioxidant, wherein the melting peak half width (H) measured using a differential scanning calorimeter (DSC) is 0.

01. ｗ ) is 7.7°C or higher, and the melting point (T ｍ ) is 159.0°C or more and 170.0°C or less, and the molecular weight distribution (Mw / Mn) is 4.1 or more.

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