Propylene-based copolymer and use of the propylene-based copolymer in the manufacture of a film

Abstract

A propylene-based copolymer composed of 60 to 90 wt% component (A), which is a polymer component whose main structural unit is a propylene-derived structural unit, and 10 to 40 wt% component (B), which is a propylene-ethylene copolymer component whose ethylene-derived structural unit content is 55 to 80 wt%, wherein the total of component (A) and component (B) is 100 wt%, wherein the ratio of the intrinsic viscosity of component (B) ([η]B) to the intrinsic viscosity of component (A) ([η]A) ([η]B / [η]A) is of a formula 1.3 < [η]B / [η]A ≤ 2.0, and the melt flow rate, measured at a temperature of 230°C and a load of 21.18 N, of the copolymer is not less than 5 g / 10 minutes and does not exceed 30 g / 10 minutes.

Description

Background of the invention 1. Field of the invention

[0001] The present invention relates to propylene-based copolymers and the use of the propylene-based copolymers in the production of a film.

[0002] In particular, it relates to propylene-based copolymers that exhibit haze suitable for a matte film and that exhibit excellent appearance and rigidity, and also relates to the use of the propylene-based copolymer in the manufacture of a film. In this specification, the term "a film exhibits excellent appearance" primarily means that the film has no or almost no fisheyes large enough to be visually detected. 2. State of the art

[0003] Polypropylene exhibits excellent rigidity, heat resistance, and suitability as packaging, and is therefore widely used in the field of packaging materials such as food packaging and fiber packaging. In recent years, luxurious matte films comprising polypropylene as a main component have been desired. For example, JP-A-56-38339 discloses that a film exhibiting improved haze, which is a measure indicating the degree of light transmittance, can be obtained from a polypropylene resin composition in which a crystalline propylene-ethylene block copolymer is blended with an organic peroxide such that the temperature at which a half-life of 10 hours is obtained is 60°C or higher. JP-A-2-69549 discloses that a product exhibiting improved matting effect can be obtained from a polypropylene-based resin composition obtainable by a manufacturing process.JP-A-2003-213068 discloses that a polypropylene-based resin composition comprising a propylene-based copolymer consisting of a polymer component obtained by polymerizing a monomer component mainly comprising propylene and a propylene-ethylene copolymer component and a propylene-based polymer improves the appearance and moist feeling of a matte film by heat-treating a mixture of a block copolymer containing a propylene-based homopolymer part and an ethylene-propylene random copolymer part obtained by polymerization on the same catalyst, polyethylene, a crosslinking aid, and a radical generator.

[0004] However, further improvement in appearance, especially in the balance between haze and the amount of fisheye, was desired for matte films.

[0005] The document DE 693 13 056 T2 describes a polypropylene block copolymer obtained using a Ziegler-Natta catalyst by polymerizing in a first step a monomer comprising propylene, wherein first, in the absence of an inert solvent, a polymer comprising polypropylene in an amount of 60 to 75 wt.% of the total amount of the polypropylene block copolymer (component A) is obtained, and then, in a second step, polymerizing a mixture of ethylene and propylene in the gas phase, wherein an ethylene-propylene copolymer (component B) having an ethylene content of 20 to 50 wt.% in an amount of 25 to 40 wt.% of the total amount of polymer is obtained, and melt-kneading the resulting polypropylene block copolymer, wherein the melt index of the melt-kneaded polypropylene block copolymer, measured according to JIS K7210 Condition 14, is 0.5 to 10 g / 10 minutes and the Intrinsic viscosity of component B ([η]B) at least 2.0 dl / g and the ratio ([η]B / [η]A), where [η]A is the intrinsic viscosity of component A, is 1.8 or less. Summary of the invention

[0006] An object of the present invention is to provide a propylene-based copolymer which has a haze suitable for a matte film and which has excellent appearance (fisheye) and rigidity when formed into a film.

[0007] The present invention relates to a propylene-based copolymer composed of 60 to 90 wt% of component (A) which is a polymer component whose main structural unit is a structural unit derived from propylene, and 10 to 40 wt% of component (B) which is a propylene-ethylene copolymer component whose content of an ethylene-derived structural unit is 55 to 80 wt%, the total of component (A) and component (B) being 100 wt%, wherein the ratio of the intrinsic viscosity of component (B) ([η]B) to the intrinsic viscosity of component (A) ([η]A) ([η]B / [η]A) satisfies a formula of 1.3 < [η]B / [η]A ≤ 2.0, and the melt flow rate, measured at a temperature of 230°C and a load of 21.18 N, of the copolymer is not less than 5 g / 10 minutes and not more than 30 g / 10 minutes.

[0008] Furthermore, the present invention relates to the use of the propylene-based copolymer in the production of a film, in one preferred embodiment an unstretched film and in another preferred embodiment a matte film. In the present invention, the term "unstretched film" refers to any film produced without undergoing any intentional stretching process, such as cast films. The term "matte film" refers to any film that has irregularities on its surface and exhibits low gloss.

[0009] According to the present invention, it is possible to obtain a propylene-based copolymer which has a haze suitable for a matte film and which has excellent appearance and rigidity when formed into a film. Description of the preferred embodiments

[0010] The propylene-based copolymer of the present invention is composed of a polymer component whose main structural unit is a structural unit derived from propylene (hereinafter sometimes referred to as "component (A)") and a propylene-ethylene copolymer component whose content of a structural unit derived from ethylene is 55 to 80 wt% (hereinafter sometimes referred to as "component (B)").

[0011] The "main structural unit" in component (A) of the propylene-based copolymer of the present invention refers to a structural unit that accounts for 90% by weight or more of component (A). A structural unit derived from propylene is the main structural unit of component (A). The content of the structural unit derived from propylene in component (A) is preferably 90 to 100% by weight, more preferably 95 to 100% by weight, and even more preferably 100% by weight.

[0012] In component (A), ethylene and / or an α-olefin having 4 to 12 carbon atoms may be copolymerized as needed, and the content of a structural unit derived from ethylene and / or the α-olefin having 4 to 12 carbon atoms is preferably 10 wt% or less, and more preferably 5 wt% or less. Examples of the α-olefin having 4 to 12 carbon atoms include 1-butene, 1-hexene, and 1-octene, with 1-butene being preferred. Component (A) is preferably a homopolymer of propylene.

[0013] The content of the ethylene-derived structural unit in component (B) is 55 to 80 wt%, and preferably 60 to 80 wt%, with the weight of component (B) being 100 wt%. If it is less than 50 wt%, the matting effect may be insufficient (the haze may be low), while if it exceeds 80 wt%, the appearance may deteriorate (the number of fish eyes may increase).

[0014] The component (B) has a structural unit derived from propylene in addition to a structural unit derived from ethylene, and the content of the structural unit derived from propylene is 20 to 45 wt%, and preferably 20 to 40 wt%, with the total of the content of the structural unit derived from ethylene and the content of the structural unit derived from propylene being 100 wt%.

[0015] The content of component (A) in the propylene-based copolymer of the present invention is 60 to 90% by weight, and the content of component (B) is 10 to 40% by weight, with the total of component (A) and component (B) being 100% by weight. Preferably, the content of component (A) is 60 to 87% by weight and the content of component (B) is 13 to 40% by weight, and more preferably, the content of component (A) is 65 to 85% by weight and the content of component (B) is 15 to 35% by weight. When the content of component (A) is less than 60 wt% (in other words, the content of component (B) exceeds 40 wt%), the rigidity may deteriorate, and when the content of component (A) exceeds 90 wt% (in other words, the content of component (B) is less than 10 wt%), the matting effect may become insufficient (that is, the haze may become low).

[0016] The intrinsic viscosity of component (A) in the propylene-based copolymer of the present invention (hereinafter sometimes referred to as "[η]A") is preferably 0.9 to 3.5 dl / g, and more preferably 1.0 to 3.5 dl / g, and even more preferably 1.0 to 3.1 dl / g. If [η]A is less than 0.9 dl / g, the appearance may deteriorate (i.e., the number of fish eyes may increase), and if [η]A exceeds 3.5 dl / g, the flowability is low, so that the processability may deteriorate.

[0017] The intrinsic viscosity of component (B) in the propylene-based copolymer of the present invention (hereinafter sometimes referred to as "[η]B") is preferably 1.8 to 4.5 dl / g, and more preferably 2.0 to 4.5 dl / g, and even more preferably 2.0 to 4.0 dl / g. If the [η]B is less than 1.8 dl / g, the matting effect may become insufficient (i.e., haze may be low), while if the [η]B exceeds 4.5 dl / g, the appearance may deteriorate (i.e., the number of fish eyes may increase). In the present invention, the intrinsic viscosities of component (A) and component (B) of a propylene-based copolymer are measured in tetralin at 135°C using an Ubbelohde viscometer.

[0018] The ratio of [η]B to the intrinsic viscosity of component (A) in the propylene-based copolymer of the present invention (hereinafter sometimes referred to as "[η]B / [η]A") is in the range of 1.3 < [η]B / [η]A ≤ 2.0, preferably 1.4 ≤ [η]B / [η]A ≤ 2.0, and more preferably 1.4 ≤ [η]B / [η]A ≤ 1.8. When the [η]B / [η]A is 1.3 or less, the matting effect may become insufficient (i.e., the haze may be low), while when it exceeds 2.0, the appearance may deteriorate (i.e., the number of fish eyes may increase).

[0019] The melt flow rate of the propylene-based copolymer of the present invention is not less than 5 g / 10 minutes and not more than 30 g / 10 minutes, preferably not less than 5 g / 10 minutes and not more than 20 g / 10 minutes, and more preferably not less than 5 g / 10 minutes and less than 10 g / 10 minutes. If the melt flow rate of a propylene-based copolymer is less than 5 g / 10 minutes, the flowability is low, so processability may deteriorate, and if it exceeds 30 g / 10 minutes, the appearance may deteriorate (i.e., the number of fish eyes may increase). In the present invention, the melt flow rate of a propylene-based copolymer is measured at a temperature of 230°C and a load of 21.18 N according to JIS K7210.The melt flow rate of the propylene-based copolymer of the present invention can be adjusted by adding a molecular weight adjusting agent such as hydrogen gas and metal compounds and ethylene in an appropriate amount at each step of polymerization or by adjusting the polymerization conditions such as temperature and pressure in polymerization.

[0020] The process for producing the propylene-based copolymer of the present invention may, for example, be a process of polymerizing the starting materials, ie, propylene, ethylene, etc., using a conventional stereoregular catalyst.

[0021] Examples of the stereoregular catalyst include a catalyst formed by bringing into contact with each other a solid titanium-containing catalyst component, a catalyst component of an organometallic compound, and an electron donor further used as needed, a catalyst system formed by bringing into contact with each other a compound of a transition metal of Group 4 of the Periodic Table, the compound having a cyclopentadienyl ring, and an alkylaluminoxane, and a catalyst obtained by bringing into contact with each other a compound of a transition metal of Group 4 of the Periodic Table, the compound having a cyclopentadienyl ring, and a compound capable of reacting with the compound of the transition metal to form an ionic complex, and an organoaluminum compound.Particularly preferred is the catalyst formed by bringing into contact with each other a solid titanium-containing catalyst component, an organometallic compound catalyst component, and an electron donor further used as needed.

[0022] The solid titanium-containing catalyst component may, for example, be a solid catalyst component containing a trivalent titanium compound to be formed by bringing into contact with each other a precursor of a solid catalyst component obtained by reducing a titanium compound with an organomagnesium compound in the presence of a silicon compound, a halide compound (for example, titanium tetrachloride) and an electron donor (for example, an ether compound and a mixture of an ether compound and an ester compound).

[0023] Examples of the catalyst component of the organometallic compound include organoaluminum compounds each having at least one aluminum-carbon bond in the molecule, and preferably, the catalyst component of the organometallic compound is trialkylaluminum, a mixture of trialkylaluminum and dialkylaluminum halide, or alkylaluminoxane, and more preferably, triethylaluminum, triisobutylaluminum, a mixture of triethylaluminum and diethylaluminum chloride, or tetraethyldialuminoxane.

[0024] Examples of the electron donor include oxygen-containing compounds, nitrogen-containing compounds, phosphorus-containing compounds, and sulfur-containing compounds; oxygen-containing compounds or nitrogen-containing compounds are preferred, oxygen-containing compounds are more preferred, and alkoxysilicon compounds or ethers are even more preferred.

[0025] A specific example is a catalyst prepared by bringing into contact with each other a solid catalyst component containing a trivalent titanium compound (hereinafter sometimes referred to as “component (a)”), an organoaluminum compound (hereinafter sometimes referred to as “component (b)”) and a silicon compound having a Si-OR 2 Binding (R 2 represents a hydrocarbon residue having 1 to 20 carbon atoms) (hereinafter sometimes referred to as “component (c)”), wherein the trivalent titanium compound-containing solid catalyst component is prepared by bringing into contact with each other an ester compound, an ether compound, titanium tetrachloride and a solid product obtained by reducing a titanium compound represented by a formula Ti(OR 1 ) n X 4-n (R 1represents a hydrocarbon radical having 1 to 20 carbon atoms, x represents a halogen atom and n represents a number corresponding to 0 < n ≤ 4) with an organomagnesium compound in the presence of a silicon compound having an Si-O bond.

[0026] The amount of the organoaluminum compound used is usually 1 to 2000, preferably 5 to 1500 in the molar ratio of Al atoms in component (b) / Ti atoms in component (a) and usually 0.02 to 500, preferably 0.05 to 50 in the molar ratio of component (c) / Al atoms in component (b).

[0027] The polymerization process for producing the propylene-based copolymer of the present invention can be carried out by a batch system (a system of introducing the starting materials into a reactor to react them) or can be carried out by a continuous system (a system of carrying out the reaction in reactors connected to each other).Further examples include slurry polymerization or solution polymerization using an inert hydrocarbon solvent such as propane, butane, isobutane, pentane, hexane, heptane, and octane, bulk polymerization using an olefin that is liquid at the polymerization temperature, or gas-phase polymerization and a bulk gas-phase polymerization method, wherein the above are carried out continuously. Preferred in view of productivity is a method wherein a polymer component whose main component is a structural unit derived from propylene (component (A)) is prepared in a first step, and then a propylene-ethylene copolymer component (component (B)) is prepared by polymerizing propylene and ethylene in a gas phase in a second step. The polymerization temperature is usually -30 to 300°C, and preferably 20 to 180°C.From an industrial and economic point of view, the polymerization pressure is usually from ambient pressure to 10 MPa, and preferably from 200 kPa to 5 MPa. In particular, the second step described below is preferably a gas-phase polymerization.

[0028] Examples of the method for adjusting the intrinsic viscosities and ethylene contents of the polymer component whose main component is a structural unit derived from propylene (component (A)) and the propylene-ethylene copolymer component (component (B)) of the propylene-based copolymer include a method of adding a molecular weight adjusting agent such as hydrogen gas and metal compounds and ethylene in an appropriate amount at each step of the polymerization and a method of adjusting the temperature, pressure, or the like in the polymerization.

[0029] The contents of the polymer component whose main component is a propylene-derived structural unit (component (A)) and the propylene-ethylene copolymer component (component (B)) of the propylene-based copolymer can be adjusted by the polymerization time, the size of a polymerization vessel, the retained amount of a polymer in a polymerization vessel, the polymerization temperature, the polymerization pressure, or the like in the production of the propylene-based copolymer. As needed, drying may be performed at a temperature not higher than a temperature at which polypropylene melts to remove the residual solvent of the polypropylene, the super-low molecular weight oligomer formed as a by-product during production, etc. Examples of the drying method include those disclosed in JP-A-55-75410 and Japanese Patent No. 2565753.

[0030] If necessary, the propylene-based copolymer of the present invention can form a propylene-based resin composition by adding additives and other resins. Examples of the additives include antioxidants, UV absorbers, antistatic agents, lubricants, nucleating agents, pressure-sensitive adhesives, antifogging agents, and antiblocking agents. Regarding the blended amount in the case of adding an additive, the amount of the additive is preferably 0.001 to 5 parts by weight, more preferably 0.01 to 2 parts by weight, based on 100 parts by weight of the propylene-based copolymer. Regarding the blended amount in the case of adding another resin, the amount of the resin is preferably 0.5 to 30 parts by weight, more preferably 1 to 25 parts by weight, based on 100 parts by weight of the propylene-based copolymer.

[0031] To improve the matting effect, the propylene-based copolymer may contain a phenolic antioxidant or a phosphorus-containing antioxidant.

[0032] Examples of the above-mentioned phenolic antioxidant include hindered phenol antioxidants or mono-hindered phenol antioxidants such as 2,6-di-tert-butyl-4-methylphenol, tetrakis[methylene-3-(3',5'-di-tert-butyl-4-hydroxyphenyl)propionate]methane, octadecyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], 3,9-bis[2-{3-(3-tert-butyl-4-hydroxy-5-methylphenyl)propionyloxy}-1,1-dimethylethyl]-2,4,8,10-tetraoxaspiro-[5.5]undecane, 1,3,5-tris-2-[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionyloxy]ethyl isocyanate, 1,3,5-trimethyl-2,4,6-tris(3,5-di-tert-butyl-4-hydroxybenzyl)benzene, tris(3,5-di-tert-butyl-4-hydroxybenzyl) isocyanurate, 1,3,5-tris(4-tert-butyl-3-hydroxy-2,6-dimethylbenzyl) isocyanurate, Pentaerythritol tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], triethylene glycol N-bis-3-(3-tert-butyl-5-methyl-4-hydroxyphenyl)propionate, 1,6-hexanediolbis[(3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate)], 2,2-Thiobisdiethylenebis[(3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate)], 2,2'-methylenebis(4-methyl-6-tert-butylphenol), 2,2'-methylenebis(4-ethyl-6-tert-butylphenol), 2,2'-methylenebis(4,6-di-tert-butylphenol), 2,2'-Ethylidenebis(4,6-di-tert-butylphenol) (CHEMINOX 1129), 2,2'-Butylidenebis(4-methyl-6-tert-butylphenol), 4,4'-Butylidenebis(3-methyl-6-t-butylphenol), 2-tert-Butyl-6-(3-tert-buty1-2-hydroxy-5-methylbenzyl)-4-methylphenyl acrylate, 2,4-Di-tert-amyl-6-(1-(3,5-di-tert-amyl-2-hydroxyphenyl)-ethyl)phenylacrylate and α-tocopherols, represented by vitamin E, are listed.

[0033] Beispiele des vorstehend genannten Phosphor enthaltenden Antioxidationsmittels schließen Triphenylphosphit, Tris(nonylphenyl)phosphit, Tris(2,4-di-tert-butylphenyl)phosphit, Trilaurylphosphit, Trioctadecylphosphit, Distearylpentaerythritdiphosphit, Diisodecylpentaerythritdiphosphit, Bis(2,4-di-tert-butylphenyl)pentaerythritdiphosphit, Bis(2,4-di-tert-butyl-6-methylphenyl)pentaerythritdiphosphit, Bis(2,6-di-tert-butyl-4-methylphenyl)pentaerythrit-diphosphit, Bis(2,4,6-tri-tert-butylphenyl)pentaerythritdiphosphit, Tristearylsorbitoltriphosphit, Tetrakis(2,4-di-tert-butylphenyl)-4,4'-diphenylendiphosphit, 2,2'-Methylenbis(4,6-di-tert-butylphenyl)-2-ethylhexylphosphit, 2,2'-Ethylidenbis(4,6-di-tert-butylphenyl)fluor-phosphit, Bis(2,4-di-tert-butyl-6-methylphenyl)ethylphosphit, Bis(2,4-di-tert-butyl-6-methylphenyl)methylphosphit, 2-(2,4,6-Tri-tert-butylphenyl)-5-ethyl-5-butyl-1,3,2-oxaphosphorinan, 2,2',2''-Nitrilo[triethyltris(3,3',5,5'-tetra-tert-butyl-1,1'-biphenyl-2,2'-diyl)phosphit],2,4,8,10-Tetra-tert-butyl-6-[3-(3-methyl-4-hydroxy-5-tert-butylphenyl)propoxy]dibenzo-[d,f][1,3,2]dioxaphosphepine and mixtures of at least two types of these.

[0034] Examples of the other resin include olefin-based resins such as polyethylene, and elastomers that are copolymers of ethylene and an α-olefin, which can be either products produced using heterogeneous catalysts or products produced using homogeneous catalysts (e.g., metallocene catalysts). Also listed are styrene-based copolymer rubbers produced by hydrogenating styrene-butadiene-styrene copolymers or styrene-isoprene-styrene copolymers.

[0035] The propylene-based copolymer of the present invention or the above-mentioned propylene-based resin composition is usually melt-kneaded before molding into a film. The MFR ratio of the propylene-based copolymer of the present invention or the above-mentioned propylene-based resin composition (i.e., the MFR of the propylene-based copolymer (propylene-based resin composition) after melt-kneading / the MFR of the propylene-based copolymer (propylene-based resin composition) before melt-kneading) is preferably 0.7 to 3.5, more preferably 0.8 to 3.0, and even more preferably 0.8 to 2.0 in view of excellent processability and appearance. In the case of using the above-mentioned propylene-based resin composition for melt-kneading, the MFR of the propylene-based copolymer after melt-kneading means a value of the MFR of the propylene-based resin composition obtained after melt-kneading.

[0036] The above-mentioned melt-kneading can be carried out using a conventional method and apparatus. Examples of the method include a method in which the propylene-based copolymer and various additives are mixed with a mixing device such as a Henschel mixer, a ribbon blender, and a tumbler, and then melt-kneaded; and a method in which the propylene-based copolymer and various additives are continuously introduced at a predetermined rate with a metered feeder to obtain a uniform mixture, and then the mixture is melt-kneaded using an extruder equipped with a single screw or two or more screws, a Banbury mixer, a roll-type kneader, or the like.

[0037] The temperature of the above-mentioned melt kneading is preferably 180°C to 350°C, more preferably 180°C to 320°C, and even more preferably 180°C to 300°C.

[0038] The film produced using the propylene-based copolymer can be either a single-layer film or a multilayer film containing at least one layer made of a film of the present invention. The film produced using the propylene-based copolymer can be either an unstretched film or a stretched film produced by stretching a polypropylene-based film of the present invention. It is preferably an unstretched film.

[0039] Multilayer films are films each consisting of a layer of a film of the present invention and other layer or layers, and examples of the other layer or layers include a layer consisting of a propylene homopolymer or a layer of a propylene-based random copolymer consisting of propylene and at least one comonomer selected from the group consisting of ethylene and α-olefins having 4 or more carbon atoms, a block copolymer consisting of propylene and at least one comonomer selected from the group consisting of ethylene and α-olefins having 4 or more carbon atoms, and a layer consisting of a mixture of at least one propylene-based polymer selected from the group consisting of the above-mentioned propylene homopolymer,the above-mentioned propylene-based random copolymer and the above-mentioned propylene-based block copolymer and at least one macromolecular substance selected from the group consisting of olefin-based resins such as polyethylene and polybutene, and an elastomer which is a copolymer of ethylene and an α-olefin, a layer of a biaxially stretched polypropylene film, a layer of an unstretched or stretched nylon film, and a layer of a stretched poly(ethyl terephthalate) film.

[0040] The film produced using the propylene-based copolymer can be produced by, for example, a T-die process, a blow molding process, a calendering process, or the like when the film is a single-layer film. When the film produced using the propylene-based copolymer is a multi-layer film, it can be produced by, for example, a coextrusion processing process, an extrusion lamination process, a heat lamination process, and a dry lamination process.

[0041] The film produced using the propylene-based copolymer preferably has a thickness of 5 to 500 µm, more preferably 5 to 100 µm.

[0042] The film produced using the propylene-based copolymer can be subjected to surface treatment such as corona discharge treatment, flame treatment, plasma treatment and ozonization by a method conventionally used in the industry.

[0043] Applications of the film produced using the propylene-based copolymer include packaging applications, for example, applications for packaging food, fibers, various goods, and the like. The film produced using the propylene-based copolymer is preferably a matte film. The haze suitable for a matte film is typically 65% ​​or more, and preferably 70% or more. The haze of the film produced using the propylene-based copolymer can be adjusted by adjusting, for example, the content of an ethylene-derived structural unit in the component (B), the content of the component (B), the intrinsic viscosity of the component (B), or the ratio of the intrinsic viscosity of the component (B) to the intrinsic viscosity of the component (A).Furthermore, it can be adjusted by adjusting the processing conditions used in the production of a film from a propylene-based copolymer of the present invention. Haze is measured according to JIS K7105. EXAMPLES

[0044] The present invention will be described below through Examples and Comparative Examples. The measurements of the respective items disclosed in the Examples and Comparative Examples were carried out using the following methods.

[0045] (1) Content (unit: wt%) of a polymer component whose main structural unit is a structural unit derived from propylene (component (A)) and a propylene-ethylene copolymer component whose content of a structural unit derived from ethylene is 55 to 80 wt% (component (B)).

[0046] The content of component (A) (hereinafter sometimes referred to as “P A”) and the content of component (B) (hereinafter sometimes referred to as “P B “) were determined from the mass balance in the preparation of component (A) and component (B) of a propylene-based copolymer.

[0047] (2) Ethylene content (unit: wt%) of a propylene-ethylene copolymer component (component (B)) of a propylene-based copolymer The IR spectrum of the whole body of a propylene-based copolymer was measured, and the ethylene content of component (B) was determined from the following formula (1) according to the method concerning (ii) a block copolymer disclosed on page 616 of Polymer Analysis Handbook (1995, Kinokuniya Co., Ltd.): EB=(ET−EA×PA) / PB where E T , E A and E B represent the ethylene contents of the total body of the propylene-based copolymer, component (A) and component (B), respectively, and P A and P Brepresent the contents of component (A) or component (B). (3) Intrinsic viscosity ([η], unit: dl / g)

[0048] The measurement was carried out in Tetralin at 135°C using an Ubbelohde viscometer. (3-1) Intrinsic viscosities ([η]A, [η]B) of component (A) and component (B)

[0049] The intrinsic viscosity ([η]B) of the component (B) was calculated from the following formula (2) using the intrinsic viscosity ([η]A) of the component (A) sampled after completion of the polymerization of the polymerization step (4) described below, the intrinsic viscosity of the whole body of a copolymer obtained after completion of the polymerization of the polymerization step (5) described below (hereinafter sometimes referred to as “[η]T”), and the content (P A ) of the component (A) and the content (P B ) of component (B). [η]A×PA / 100+[η]B×PB / 100=[η]T (4) Melt flow rate (MFR, unit g / 10 minutes)

[0050] The melt flow rate of a propylene-based copolymer was measured at a temperature of 230°C and a load of 21.18 N according to JIS K7210. (5) Haze (unit: %) and gloss (unit: %)

[0051] The measurement was carried out according to JIS K7105. (6) Stiffness (Young's modulus, unit: MPa)

[0052] Using a film (120 mm × 30 mm) (sampled so that the film forming direction (MD) coincides with the direction of the longer side), a tensile test was conducted at a clamping distance of 60 mm and a tensile speed of 5 mm in an atmosphere of 23°C and 50% humidity using an AUTOSTRAIN manufactured by Yasuda Seiki Seisakusho, Ltd., and an initial elastic modulus was determined from the slope of the tangent of a tensile-strain curve at its origin. (7) Assessment of appearance (the amount of fish eyes, unit: fish eyes / 100 cm 2 )

[0053] For a film with a thickness of 30 µm, fisheyes with a diameter of 50 µm or more were counted using a digital defect inspection device (GX70LT, manufactured by Mamiya-OP Co., Ltd.). The inspection conditions included an inspection threshold of 30 or more, a light source pickup of 1.0, a reading speed of 30 m / minute, a minimum detection size of 4 pixels in length and 2 pixels in width, an average transmitted light quantity of 60%, and a measurement range of 17 cm in length and 12 cm in width. [Example 1] Preparation example of propylene-based copolymer PP-I

[0054] Example 1 has a content of a structural unit derived from ethylene of less than 55 wt.% in component (B) and is therefore to be regarded as a reference example. [Synthesis of the solid catalyst]

[0055] A solid catalyst was synthesized by the method disclosed in Example 1 of JP-A-2009-173870. [Prepolymerization]

[0056] In a 3-liter SUS autoclave equipped with a stirrer, 1.5 liters of completely dehydrated and degassed n-hexane, 20 mmol of triethylaluminum, 2.0 mmol of cyclohexylethyldimethoxysilane, and 16 g of the above-mentioned solid catalyst were charged. Prepolymerization was carried out by continuously adding 32 g of propylene for about 40 minutes while maintaining the temperature in the autoclave at about 5 to 10°C. Then, the prepolymerized slurry was transferred to a 200-liter SUS autoclave equipped with a stirrer, and 132 liters of liquid butane were added to obtain a slurry of a prepolymerized catalyst component. Preparation of component (A)[Polymerization step (1)]

[0057] In a tank-type reactor with a capacity of 40 L and equipped with a stirrer, continuous polymerization was carried out for 0.48 hours by continuously introducing propylene, hydrogen, triethylaluminum, cyclohexylethyldimethoxysilane, and the slurry of the prepolymerized catalyst component, maintaining the polymerization temperature at 78°C, the stirring speed at 150 rpm, and the amount of liquid in the reactor at 18 L, and adjusting the introduction rate of propylene to 15 kg / hour, the introduction rate of hydrogen to 21.6 NL / hour, the introduction rate of triethylaluminum to 40 mmol / hour, the introduction rate of cyclohexylethyldimethoxysilane to 6 mmol / hour, and the introduction rate of the slurry of the prepolymerized catalyst component, in terms of the solid catalyst component, to 0.39 g / hour. A polymer was withdrawn at a rate of 3.9 kg / hour. [Polymerization step (2)]

[0058] The slurry discharged from the reactor in the polymerization step (1) was continuously transferred to a tank-type reactor different from that in the polymerization step (1), and continuous polymerization was further carried out for 0.95 hours by continuously introducing propylene and hydrogen, maintaining the polymerization temperature at 75°C, the stirring speed at 150 rpm, and the amount of liquid in the reactor at 44 l, and adjusting the propylene introduction rate to 7 kg / hour and the hydrogen introduction rate to 6.3 NL / hour. A polymer was discharged at a rate of 5.7 kg / hour. [Polymerization step (3)]

[0059] A slurry discharged from the reactor in the polymerization step (2) was continuously transferred into a tank-type reactor different from that in the polymerization steps (1) and (2), and continuous polymerization was further carried out for 0.84 hours while maintaining the polymerization temperature at 70°C, the stirring speed at 150 rpm, and the amount of liquid in the reactor at 44 l. A polymer was discharged at a rate of 3.5 kg / hour. [Polymerization step (4)]

[0060] The slurry taken from the reactor in the polymerization step (3) was continuously fed into a fluidized bed reactor with a capacity of 1 m 3and equipped with a stirrer, and polymerization was carried out for 2.7 hours while continuously introducing propylene and hydrogen, and adjusting the polymerization temperature to 80°C, the polymerization pressure to 1.8 MPa, and the concentration ratio of propylene to hydrogen in the gas in the reactor to 98.14 volume% / 1.86 volume% (propylene concentration / hydrogen concentration). A polymer component (component (A)) was discharged at a rate of 5.6 kg / hour. The intrinsic viscosity ([η]A) of the obtained polymer component (component (A)) was 1.56 dl / g. Preparation of component (B)[Polymerization step (5)]

[0061] The polymer component (component (A)) taken from the reactor in the polymerization step (4) was continuously fed into a fluidized bed reactor with a capacity of 1 m 3and equipped with a stirrer, the reactor being a different reactor from the one used in the polymerization step (4), and the polymerization was carried out for 2.0 hours while continuously introducing propylene, ethylene, and hydrogen, setting the polymerization temperature to 70°C, the polymerization pressure to 1.4 MPa, and the concentration ratio of propylene to ethylene to hydrogen of the gas in the reactor to 49.2 vol% / 45.8 vol% / 5.0 vol% (propylene concentration / ethylene amount / hydrogen concentration), and adding hydrogen as a deactivator in a molar ratio, based on triethylaluminum introduced in the polymerization step (1), of 0.003. A propylene-based copolymer was taken out at a rate of 5.7 kg / hour. The propylene-based copolymer thus obtained is called propylene-based copolymer PP-I.The intrinsic viscosity ([η]T) of the obtained propylene-based copolymer was 1.80 dl / g.

[0062] The results of the analysis of the obtained propylene-based copolymer are shown in Table 1. [Example 2] Preparation example of propylene-based copolymer PP-II

[0063] The polymerization was carried out as for PP-I, except that the polymerization was carried out for 2.1 hours, adjusting the concentration ratio of propylene to ethylene to hydrogen of the gas in the reactor to 39.1 vol% / 55.0 vol% / 5.9 vol% (propylene concentration / ethylene amount / hydrogen concentration) and adding oxygen as a deactivator in a molar ratio of 0.004 to the triethylaluminum to be introduced in the polymerization step (1) in [polymerization step (5)] of the above-described polymerization example of PP-I. Thus, a propylene-based copolymer PP-II was prepared.

[0064] The results of the analysis of the obtained propylene-based copolymer are shown in Table 1. [Example 3] Preparation example of propylene-based copolymer PP-III

[0065] The polymerization was carried out as for PP-I, except that the polymerization was carried out for 2.2 hours, adjusting the propylene to ethylene to hydrogen concentration ratio of the gas in the reactor to 29.4 vol% / 63.7 vol% / 6.9 vol% (propylene concentration / ethylene amount / hydrogen concentration) and adding oxygen as a deactivator in a molar ratio of 0.01 to the triethylaluminum to be introduced in the polymerization step (1) in [Polymerization Step (5)] of the above-described polymerization example of PP-I. Thus, a propylene-based copolymer PP-III was prepared.

[0066] The results of the analysis of the obtained propylene-based copolymer are shown in Table 1. [Comparative Example 1] Preparation Example of Propylene-Based Copolymer PP-IV

[0067] The polymerization was carried out as for PP-I, except that the polymerization was carried out for 2.1 hours, adjusting the concentration ratio of propylene to ethylene to hydrogen of the gas in the reactor to 33.7 vol% / 63.7 vol% / 2.6 vol% (propylene concentration / ethylene amount / hydrogen concentration) and adding oxygen as a deactivator in a molar ratio of 0.0024 to the triethylaluminum to be introduced in the polymerization step (1) in [polymerization step (5)] of the above-described polymerization example of PP-I. Thus, a propylene-based copolymer PP-IV was prepared.

[0068] The results of the analysis of the obtained propylene-based copolymer are shown in Table 1. [Comparative Example 2] Preparation example of propylene-based copolymer PP-V

[0069] The synthesis of a solid catalyst and prepolymerization were carried out in the same manner as PP-I. Preparation of component (A)[Polymerization step (1)]

[0070] In a tank-type reactor with a capacity of 40 l and equipped with a stirrer, continuous polymerization was carried out for 0.4 hours by continuously introducing propylene, hydrogen, triethylaluminum, cyclohexylethyldimethoxysilane, and the slurry of the prepolymerized catalyst component, maintaining the polymerization temperature at 78°C, the stirring speed at 150 rpm, and the amount of liquid in the reactor at 18 l, and adjusting the introduction rate of propylene to 15 kg / hour, the introduction rate of hydrogen to 30 NL / hour, the introduction rate of triethylaluminum to 40 mmol / hour, the introduction rate of cyclohexylethyldimethoxysilane to 6 mmol / hour, and the introduction rate of the slurry of the prepolymerized catalyst component, in terms of the solid catalyst component, to 0.52 g / hour. A polymer was withdrawn at a rate of 3.9 kg / hour. [Polymerization step (2)]

[0071] The slurry discharged from the reactor in polymerization step (1) was continuously transferred to a tank-type reactor different from that in polymerization step (1), and continuous polymerization was further carried out for 0.9 hours while continuously introducing propylene and hydrogen, maintaining the polymerization temperature at 75°C, the stirring speed at 150 rpm, and the amount of liquid in the reactor at 44 l, and adjusting the propylene introduction rate to 7 kg / hour and the hydrogen introduction rate to 10 NL / hour. A polymer was discharged at a rate of 5.4 kg / hour. [Polymerization step (3)]

[0072] The slurry discharged from the reactor in polymerization step (2) was continuously transferred to a tank-type reactor different from that used in polymerization steps (1) and (2), and continuous polymerization was further carried out for 0.8 hours while maintaining the polymerization temperature at 70°C, the stirring speed at 150 rpm, and the amount of liquid in the reactor at 44 L. A polymer was discharged at a rate of 3.3 kg / hour. [Polymerization step (4)]

[0073] The slurry taken from the reactor in the polymerization step (3) was continuously fed into a fluidized bed reactor with a capacity of 1 m 3and equipped with a stirrer, and the polymerization was carried out for 2.6 hours with the continuous introduction of propylene and hydrogen, and adjusting the polymerization temperature to 80°C, the polymerization pressure to 1.8 MPa, and the propylene to hydrogen concentration ratio of the gas in the reactor to 97.0 vol% / 3.0 vol% (propylene concentration / hydrogen concentration). A polymer component (component (A)) was withdrawn at a rate of 7 kg / hour. The intrinsic viscosity ([η]A) of the obtained polymer component (component (A)) was 1.39 dl / g. Preparation of component (B)[Polymerization step (5)]

[0074] A polymer component (component (A)) taken from the reactor in the polymerization step (4) was continuously fed into a fluidized bed reactor with a capacity of 1 m 3and equipped with a stirrer, the reactor being a reactor different from the one used in the polymerization step (4), and the polymerization was carried out for 2.2 hours while continuously introducing propylene, ethylene, and hydrogen, setting the polymerization temperature to 70°C, the polymerization pressure to 1.4 MPa, and the concentration ratio of propylene to ethylene to hydrogen of the gas in the reactor to 27.5 vol% / 68 vol% / 4.5 vol% (propylene concentration / ethylene amount / hydrogen concentration), and adding oxygen as a deactivator in a molar ratio, based on the triethylaluminum introduced in the polymerization step (1), of 0.067. A propylene-based copolymer was taken out at a rate of 4.3 kg / hour. The propylene-based copolymer thus obtained is called propylene-based copolymer PP-V.The intrinsic viscosity ([η]T) of the obtained propylene-based copolymer was 1.69 dl / g.

[0075] The results of the analysis of the obtained propylene-based copolymer are shown in Table 1. [Comparative Example 3] Preparation example of propylene-based copolymer PP-VI

[0076] The synthesis of a solid catalyst and prepolymerization were carried out in the same manner as PP-1. Preparation of component (A)[Polymerization step (1)]

[0077] In a tank-type reactor with a capacity of 40 L and equipped with a stirrer, continuous polymerization was carried out for 0.46 hours by continuously introducing propylene, hydrogen, triethylaluminum, cyclohexylethyldimethoxysilane, and the slurry of the prepolymerized catalyst component, maintaining the polymerization temperature at 78°C, the stirring speed at 150 rpm, and the amount of liquid in the reactor at 18 L, and adjusting the introduction rate of propylene to 15 kg / hour, the introduction rate of hydrogen to 2.3 NL / hour, the introduction rate of triethylaluminum to 40 mmol / hour, the introduction rate of cyclohexylethyldimethoxysilane to 6 mmol / hour, and the introduction rate of the slurry of the prepolymerized catalyst component, in terms of the solid catalyst component, to 0.45 g / hour. A polymer was withdrawn at a rate of 3.2 kg / hour. [Polymerization step (2)]

[0078] The slurry discharged from the reactor in the polymerization step (1) was continuously transferred to a tank-type reactor different from that in the polymerization step (1), and continuous polymerization was further carried out for 0.9 hours while continuously introducing propylene and hydrogen, maintaining the polymerization temperature at 74°C, the stirring speed at 150 rpm, and the amount of liquid in the reactor at 44 l, and adjusting the propylene introduction rate to 7 kg / hour and the hydrogen introduction rate to 0.66 NL / hour. A polymer was discharged at a rate of 4.9 kg / hour. [Polymerization step (3)]

[0079] The slurry discharged from the reactor in polymerization step (2) was continuously transferred to a tank-type reactor different from that used in polymerization steps (1) and (2), and continuous polymerization was further carried out for 0.8 hours while maintaining the polymerization temperature at 70°C, the stirring speed at 150 rpm, and the amount of liquid in the reactor at 44 L. A polymer was discharged at a rate of 3.1 kg / hour. [Polymerization step (4)]

[0080] The slurry taken from the reactor in the polymerization step (3) was continuously fed into a fluidized bed reactor with a capacity of 1 m 3and equipped with a stirrer, and polymerization was carried out for 2.8 hours while continuously introducing propylene and hydrogen, and adjusting the polymerization temperature to 80°C, the polymerization pressure to 1.8 MPa, and the propylene to hydrogen concentration ratio of the gas in the reactor to 99.81 vol% / 0.19 vol% (propylene concentration / hydrogen concentration). A polymer component (component (A)) was withdrawn at a rate of 6.5 kg / hour. The intrinsic viscosity ([η]A) of the obtained polymer component (component (A)) was 2.30 dl / g. Preparation of component (B)[Polymerization step (5)]

[0081] A polymer component (component (A)) taken from the reactor in the polymerization step (4) was continuously fed into a fluidized bed reactor with a capacity of 1 m 3and equipped with a stirrer, the reactor being a different reactor from the one used in the polymerization step (4), and the polymerization was carried out for 2.2 hours while continuously introducing propylene, ethylene, and hydrogen, setting the polymerization temperature to 70°C, the polymerization pressure to 1.4 MPa, and the concentration ratio of propylene to ethylene to hydrogen of the gas in the reactor to 31.2 vol% / 62 vol% / 6.8 vol% (propylene concentration / ethylene amount / hydrogen concentration), and adding oxygen as a deactivator in a molar ratio, based on the triethylaluminum introduced in the polymerization step (1), of 0.029. A propylene-based copolymer was taken out at a rate of 4.7 kg / hour. The propylene-based copolymer thus obtained is called propylene-based copolymer PP-VI.The intrinsic viscosity ([η]T) of the obtained propylene-based copolymer was 2.30 dl / g.

[0082] The results of the analysis of the obtained propylene-based copolymer are shown in Table 1. [Example 4]

[0083] Example 4 has a content of an ethylene-derived structural unit of less than 55 wt% due to the use of the propylene-based copolymer PP-1 in component (B) and is therefore to be regarded as a reference example.

[0084] To 100 parts by weight of propylene-based copolymer PP-I, 0.01 part by weight of hydrotalcite (DHT4C, manufactured by Kyowa Chemical Industry Co., Ltd.), 0.075 part by weight of SUMILIZER GP (2,4,8,10-tetra-tert-butyl-6-[3-(3-methyl-4-hydroxy-5-tert-butylphenyl)propoxy]dibenzo[d,f][1,3,2]dioxaphosphepine, manufactured by Sumitomo Chemical Co., Ltd.), 0.075 part by weight of SUMILIZER GS (2,4-di-tert-amyl-6-[1-(3,5-di-tert-amyl-2-hydroxyphenyl)ethyl]phenyl acrylate, manufactured by Sumitomo Chemical Co., Ltd.), and 0.1 part by weight of erucaamide (NEUTRON-S, manufactured by Nippon Fine Chemical Co., Ltd.), and then the resultant was melt-kneaded at 250°C using a 40 mm diameter single-screw extruder (Model VS40-28, manufactured by Tanabe Plastics Machinery Co., Ltd., equipped with a full-blade screw) to obtain pellets. The resulting pellets had an MFR of 5.0 g / 10 minutes.

[0085] The resulting pellets were subjected to melt extrusion at a resin temperature of 250°C using a 50 mm diameter T-die film extruder (film extruder V-50-F600, manufactured by Tanabe Plastics Machinery Co., Ltd., with a 400 mm wide T-die). The melt extrudate was cooled over a chill roll circulating cooling water at 50°C, yielding a film with a thickness of 30 µm. The MFR, haze, gloss, Young's modulus, and appearance evaluation of the resulting film are listed in Table 2. [Example 5]

[0086] Pellets were obtained in the same manner as Example 4, except that the propylene-based copolymer was changed to PP-II. The resulting pellets had an MFR of 5.3 g / 10 minutes.

[0087] The resulting pellets were melt-extruded in the same manner as Example 4 to obtain a 30 µm thick film. The MFR, haze, gloss, Young's modulus, and appearance evaluation of the resulting film are shown in Table 2. [Example 6]

[0088] Pellets were obtained in the same manner as Example 4, except that the propylene-based copolymer was changed to PP-III. The resulting pellets had an MFR of 5.4 g / 10 minutes.

[0089] The resulting pellets were melt-extruded in the same manner as Example 4 to obtain a 30 µm thick film. The MFR, haze, gloss, Young's modulus, and appearance evaluation of the resulting film are shown in Table 2. [Comparison example 4]

[0090] Pellets were obtained in the same manner as Example 4, except that the propylene-based copolymer was changed to PP-IV. The resulting pellets had an MFR of 4.0 g / 10 minutes.

[0091] The resulting pellets were melt-extruded in the same manner as Example 4 to obtain a 30 µm thick film. The MFR, haze, gloss, Young's modulus, and appearance evaluation of the resulting film are shown in Table 2. [Comparison Example 5]

[0092] Pellets were obtained in the same manner as Example 4, except that the propylene-based copolymer was changed to PP-V. The resulting pellets had an MFR of 9.0 g / 10 minutes.

[0093] The resulting pellets were melt-extruded in the same manner as Example 4 to obtain a 30 µm thick film. The MFR, haze, gloss, Young's modulus, and appearance evaluation of the resulting film are shown in Table 2. [Comparison example 6]

[0094] Pellets were obtained in the same manner as Example 4, except that the propylene-based copolymer was changed to PP-VI. The resulting pellets had an MFR of 1.4 g / 10 minutes.

[0095] The resulting pellets were melt-extruded in the same manner as Example 4 to obtain a 30 µm thick film. The MFR, haze, gloss, Young's modulus, and appearance evaluation of the resulting film are shown in Table 2. [Example 7] Preparation example of propylene-based copolymer PP-VII

[0096] The synthesis of a solid catalyst and prepolymerization were carried out in the same manner as PP-I.

[0097] Example 7 has a content of a structural unit derived from ethylene of less than 55 wt.% in component (B) and is therefore to be regarded as a reference example. Preparation of component (A)[Polymerization step (1)]

[0098] In a tank-type reactor with a capacity of 40 l and equipped with a stirrer, continuous polymerization was carried out for 0.47 hours by continuously introducing propylene, hydrogen, triethylaluminum, cyclohexylethyldimethoxysilane, and the slurry of the prepolymerized catalyst component, maintaining the polymerization temperature at 78°C, the stirring speed at 150 rpm, and the amount of liquid in the reactor at 18 l, and adjusting the introduction rate of propylene to 15 kg / hour, the introduction rate of hydrogen to 24 NL / hour, the introduction rate of triethylaluminum to 40 mmol / hour, the introduction rate of cyclohexylethyldimethoxysilane to 6 mmol / hour, and the introduction rate of the slurry of the prepolymerized catalyst component, in terms of the solid catalyst component, to 0.40 g / hour. A polymer was withdrawn at a rate of 4.0 kg / hour. [Polymerization step (2)]

[0099] The slurry discharged from the reactor in polymerization step (1) was continuously transferred to a tank-type reactor different from that in polymerization step (1), and continuous polymerization was further carried out for 0.92 hours while continuously introducing propylene and hydrogen, maintaining the polymerization temperature at 75°C, the stirring speed at 150 rpm, and the amount of liquid in the reactor at 44 l, and adjusting the propylene introduction rate to 7 kg / hour and the hydrogen introduction rate to 8.8 NL / hour. A polymer was discharged at a rate of 5.3 kg / hour. [Polymerization step (3)]

[0100] The slurry discharged from the reactor in the polymerization step (2) was continuously transferred into a tank-type reactor different from that in the polymerization steps (1) and (2), and continuous polymerization was further carried out for 0.82 hours while maintaining the polymerization temperature at 70°C, the stirring speed at 150 rpm, and the amount of liquid in the reactor at 44 l. A polymer was discharged at a rate of 3.2 kg / hour. [Polymerization step (4)]

[0101] The slurry taken from the reactor in the polymerization step (3) was continuously fed into a fluidized bed reactor with a capacity of 1 m 3and equipped with a stirrer, and the polymerization was carried out for 2.7 hours with the continuous introduction of propylene and hydrogen, and adjusting the polymerization temperature to 80°C, the polymerization pressure to 1.8 MPa, and the propylene to hydrogen concentration ratio of the gas in the reactor to 98.1 vol% / 1.9 vol% (propylene concentration / hydrogen concentration). A polymer component (component (A)) was withdrawn at a rate of 5.8 kg / hour. The intrinsic viscosity ([η]A) of the obtained polymer component (component (A)) was 1.48 dl / g. Preparation of component (B)[Polymerization step (5)]

[0102] A polymer component (component (A)) taken from the reactor in the polymerization step (4) was continuously fed into a fluidized bed reactor with a capacity of 1 m 3and equipped with a stirrer, the reactor being a reactor different from the one used in the polymerization step (4), and the polymerization was carried out for 2.2 hours while continuously introducing propylene, ethylene, and hydrogen, setting the polymerization temperature to 70°C, the polymerization pressure to 1.4 MPa, and the concentration ratio of propylene to ethylene to hydrogen of the gas in the reactor to 48.4 vol% / 48 vol% / 3.6 vol% (propylene concentration / ethylene amount / hydrogen concentration), and adding oxygen as a deactivator in a molar ratio, based on the triethylaluminum introduced in the polymerization step (1), of 0.0122. A propylene-based copolymer was taken out at a rate of 4.4 kg / hour. The propylene-based copolymer thus obtained is called propylene-based copolymer PP-VII.The intrinsic viscosity ([η]T) of the obtained propylene-based copolymer was 1.71 dl / g.

[0103] The results of the analysis of the obtained propylene-based copolymer are shown in Table 1. [Example 8] Preparation example of propylene-based copolymer PP-VIII

[0104] The synthesis of a solid catalyst and prepolymerization were carried out in the same manner as PP-I. Preparation of component (A)[Polymerization step (1)]

[0105] In a tank-type reactor with a capacity of 40 L and equipped with a stirrer, continuous polymerization was carried out for 0.46 hours by continuously introducing propylene, hydrogen, triethylaluminum, cyclohexylethyldimethoxysilane, and the slurry of the prepolymerized catalyst component, maintaining the polymerization temperature at 78°C, the stirring speed at 150 rpm, and the amount of liquid in the reactor at 18 L, and adjusting the introduction rate of propylene to 15 kg / hour, the introduction rate of hydrogen to 24 NL / hour, the introduction rate of triethylaluminum to 40 mmol / hour, the introduction rate of cyclohexylethyldimethoxysilane to 6 mmol / hour, and the introduction rate of the slurry of the prepolymerized catalyst component, in terms of the solid catalyst component, to 0.39 g / hour. A polymer was withdrawn at a rate of 3.8 kg / hour. [Polymerization step (2)]

[0106] The slurry discharged from the reactor in polymerization step (1) was continuously transferred to a tank-type reactor different from that in polymerization step (1), and continuous polymerization was further carried out for 0.91 hours while continuously introducing propylene and hydrogen, maintaining the polymerization temperature at 75°C, the stirring speed at 150 rpm, and the amount of liquid in the reactor at 44 l, and adjusting the propylene introduction rate to 7 kg / hour and the hydrogen introduction rate to 8.8 NL / hour. A polymer was discharged at a rate of 5.1 kg / hour. [Polymerization step (3)]

[0107] The slurry discharged from the reactor in the polymerization step (2) was continuously transferred into a tank-type reactor different from that in the polymerization steps (1) and (2), and continuous polymerization was further carried out for 0.81 hours while maintaining the polymerization temperature at 70°C, the stirring speed at 150 rpm, and the amount of liquid in the reactor at 44 l. A polymer was discharged at a rate of 3.0 kg / hour. [Polymerization step (4)]

[0108] The slurry taken from the reactor in the polymerization step (3) was continuously fed into a fluidized bed reactor with a capacity of 1 m 3and equipped with a stirrer, and the polymerization was carried out for 2.9 hours with the continuous introduction of propylene and hydrogen, and adjusting the polymerization temperature to 80°C, the polymerization pressure to 1.8 MPa, and the propylene to hydrogen concentration ratio of the gas in the reactor to 98 vol% / 2 vol% (propylene concentration / hydrogen concentration). A polymer component (component (A)) was withdrawn at a rate of 5.2 kg / hour. The intrinsic viscosity ([η]A) of the obtained polymer component (component (A)) was 1.48 dl / g. Preparation of component (B)[Polymerization step (5)]

[0109] A polymer component (component (A)) taken from the reactor in the polymerization step (4) was continuously fed into a fluidized bed reactor with a capacity of 1 m 3and equipped with a stirrer, the reactor being a different reactor from the one used in the polymerization step (4), and the polymerization was carried out for 2.4 hours while continuously introducing propylene, ethylene, and hydrogen, setting the polymerization temperature to 70°C, the polymerization pressure to 1.4 MPa, and the concentration ratio of propylene to ethylene to hydrogen of the gas in the reactor to 28.1 vol% / 66 vol% / 5.9 vol% (propylene concentration / ethylene amount / hydrogen concentration), and adding oxygen as a deactivator in a molar ratio, based on the triethylaluminum introduced in the polymerization step (1), of 0.0122. A propylene-based copolymer was taken out at a rate of 3.9 kg / hour. The propylene-based copolymer thus obtained is called propylene-based copolymer PP-VIII.The intrinsic viscosity ([η]T) of the obtained propylene-based copolymer was 1.65 dl / g.

[0110] The results of the analysis of the obtained propylene-based copolymer are shown in Table 1. [Comparative Example 7] Preparation Example of Propylene-Based Copolymer PP-IX

[0111] The synthesis of a solid catalyst and prepolymerization were carried out in the same manner as PP-I. Preparation of component (A)[Polymerization step (1)]

[0112] In a tank-type reactor with a capacity of 40 l and equipped with a stirrer, continuous polymerization was carried out for 0.47 hours by continuously introducing propylene, hydrogen, triethylaluminum, cyclohexylethyldimethoxysilane, and the slurry of the prepolymerized catalyst component, maintaining the polymerization temperature at 78°C, the stirring speed at 150 rpm, and the amount of liquid in the reactor at 18 l, and adjusting the introduction rate of propylene to 15 kg / hour, the introduction rate of hydrogen to 24 NL / hour, the introduction rate of triethylaluminum to 40 mmol / hour, the introduction rate of cyclohexylethyldimethoxysilane to 6 mmol / hour, and the introduction rate of the slurry of the prepolymerized catalyst component, in terms of the solid catalyst component, to 0.40 g / hour. A polymer was withdrawn at a rate of 4.1 kg / hour. [Polymerization step (2)]

[0113] The slurry discharged from the reactor in polymerization step (1) was continuously transferred to a tank-type reactor different from that in polymerization step (1), and continuous polymerization was further carried out for 0.93 hours while continuously introducing propylene and hydrogen, maintaining the polymerization temperature at 75°C, the stirring speed at 150 rpm, and the amount of liquid in the reactor at 44 L, and adjusting the propylene introduction rate to 7 kg / hour and the hydrogen introduction rate to 8.8 NL / hour. A polymer was discharged at a rate of 5.5 kg / hour. [Polymerization step (3)]

[0114] The slurry discharged from the reactor in the polymerization step (2) was continuously transferred into a tank-type reactor different from that in the polymerization steps (1) and (2), and continuous polymerization was further carried out for 0.83 hours while maintaining the polymerization temperature at 70°C, the stirring speed at 150 rpm, and the amount of liquid in the reactor at 44 l. A polymer was discharged at a rate of 3.4 kg / hour. [Polymerization step (4)]

[0115] The slurry taken from the reactor in the polymerization step (3) was continuously fed into a fluidized bed reactor with a capacity of 1 m 3and equipped with a stirrer, and the polymerization was carried out for 2.6 hours with the continuous introduction of propylene and hydrogen, and adjusting the polymerization temperature to 80°C, the polymerization pressure to 1.8 MPa, and the propylene to hydrogen concentration ratio of the gas in the reactor to 97.9 vol% / 2.1 vol% (propylene concentration / hydrogen concentration). A polymer component (component (A)) was withdrawn at a rate of 6.0 kg / hour. The intrinsic viscosity ([η]A) of the obtained polymer component (component (A)) was 1.48 dl / g. Preparation of component (B)[Polymerization step (5)]

[0116] The polymer component (component (A)) taken from the reactor in the polymerization step (4) was continuously fed into a fluidized bed reactor with a capacity of 1 m 3and equipped with a stirrer, the reactor being a different reactor from the one used in the polymerization step (4), and the polymerization was carried out for 2.2 hours while continuously introducing propylene, ethylene, and hydrogen, setting the polymerization temperature to 70°C, the polymerization pressure to 1.4 MPa, and the concentration ratio of propylene to ethylene to hydrogen of the gas in the reactor to 65.1 vol% / 32 vol% / 2.9 vol% (propylene concentration / ethylene amount / hydrogen concentration), and adding oxygen as a deactivator in a molar ratio, based on the triethylaluminum introduced in the polymerization step (1), of 0.0124. A propylene-based copolymer was taken out at a rate of 3.5 kg / hour. The propylene-based copolymer thus obtained is called propylene-based copolymer PP-IX.The intrinsic viscosity ([η]T) of the obtained propylene-based copolymer was 1.58 dl / g.

[0117] The results of the analysis of the obtained propylene-based copolymer are shown in Table 1. [Comparative Example 8] Preparation Example of Propylene-Based Copolymer PP-X

[0118] The synthesis of a solid catalyst and prepolymerization were carried out in the same manner as PP-1. Preparation of component (A)[Polymerization step (1)]

[0119] In a tank-type reactor with a capacity of 40 L and equipped with a stirrer, continuous polymerization was carried out for 0.46 hours by continuously introducing propylene, hydrogen, triethylaluminum, cyclohexylethyldimethoxysilane, and the slurry of the prepolymerized catalyst component, maintaining the polymerization temperature at 78°C, the stirring speed at 150 rpm, and the amount of liquid in the reactor at 18 L, and adjusting the introduction rate of propylene to 15 kg / hour, the introduction rate of hydrogen to 23 NL / hour, the introduction rate of triethylaluminum to 40 mmol / hour, the introduction rate of cyclohexylethyldimethoxysilane to 6 mmol / hour, and the introduction rate of the slurry of the prepolymerized catalyst component, in terms of the solid catalyst component, to 0.41 g / hour. A polymer was withdrawn at a rate of 3.7 kg / hour. [Polymerization step (2)]

[0120] The slurry discharged from the reactor in the polymerization step (1) was continuously transferred to a tank-type reactor different from that in the polymerization step (1), and continuous polymerization was further carried out for 0.91 hours while continuously introducing propylene and hydrogen, maintaining the polymerization temperature at 75°C, the stirring speed at 150 rpm, and the amount of liquid in the reactor at 44 l, and adjusting the propylene introduction rate to 7 kg / hour and the hydrogen introduction rate to 7.5 NL / hour. A polymer was discharged at a rate of 5.1 kg / hour. [Polymerization step (3)]

[0121] The slurry discharged from the reactor in polymerization step (2) was continuously transferred to a tank-type reactor different from that used in polymerization steps (1) and (2), and continuous polymerization was further carried out for 0.81 hours while maintaining the polymerization temperature at 70°C, the stirring speed at 150 rpm, and the amount of liquid in the reactor at 44 L. A polymer was discharged at a rate of 3.3 kg / hour. [Polymerization step (4)]

[0122] The slurry taken from the reactor in the polymerization step (3) was continuously fed into a fluidized bed reactor with a capacity of 1 m 3and equipped with a stirrer, and the polymerization was carried out for 2.8 hours with the continuous introduction of propylene and hydrogen, and adjusting the polymerization temperature to 80°C, the polymerization pressure to 1.8 MPa, and the propylene to hydrogen concentration ratio of the gas in the reactor to 98.11 vol% / 1.89 vol% (propylene concentration / hydrogen concentration). A polymer component (component (A)) was withdrawn at a rate of 5.6 kg / hour. The intrinsic viscosity ([η]A) of the obtained polymer component (component (A)) was 1.56 dl / g. Preparation of component (B)[Polymerization step (5)]

[0123] A polymer component (component (A)) taken from the reactor in the polymerization step (4) was continuously fed into a fluidized bed reactor with a capacity of 1 m 3and equipped with a stirrer, the reactor being a reactor different from the one used in the polymerization step (4), and the polymerization was carried out for 2.4 hours while continuously introducing propylene, ethylene, and hydrogen, setting the polymerization temperature to 70°C, the polymerization pressure to 1.4 MPa, and the concentration ratio of propylene to ethylene to hydrogen of the gas in the reactor to 24.67 vol% / 63.3 vol% / 12.03 vol% (propylene concentration / ethylene amount / hydrogen concentration), and adding oxygen as a deactivator in a molar ratio, based on the triethylaluminum introduced in the polymerization step (1), of 0.0224. A propylene-based copolymer was taken out at a rate of 3.5 kg / hour. The propylene-based copolymer thus obtained is called propylene-based copolymer PP-X.The intrinsic viscosity ([η]T) of the obtained propylene-based copolymer was 1.58 dl / g.

[0124] The results of the analysis of the obtained propylene-based copolymer are shown in Table 1. [Example 9]

[0125] Example 9 has a content of an ethylene-derived structural unit of less than 55 wt% due to the use of the propylene-based copolymer in PP-VII in component (B) and is therefore to be regarded as a reference example.

[0126] Pellets were obtained in the same manner as Example 4, except that the propylene-based copolymer was changed to PP-VII. The resulting pellets had an MFR of 8.8 g / 10 minutes.

[0127] The resulting pellets were melt-extruded in the same manner as Example 4 to obtain a 30 µm thick film. The MFR, haze, gloss, Young's modulus, and appearance evaluation of the resulting film are shown in Table 2. [Example 10]

[0128] To 100 parts by weight of the propylene-based copolymer PP-III, 0.01 part by weight of hydrotalcite (DHT4C, manufactured by Kyowa Chemical Industry Co., Ltd.), 0.2 part by weight of IRGANOX 1010 (tetrakis[methylene-3-(3',5'-di-tert-butyl-4-hydroxyphenyl)propionate]methane, manufactured by Ciba Specialty Chemicals), 0.05 part by weight of IRGAFOS 168 (tris(2,4-di-tert-butylphenyl)phosphite, manufactured by Ciba Specialty Chemicals), and 0.1 part by weight of erucaamide (NEUTRON-S, manufactured by Nippon Fine Chemical Co., Ltd.) were previously mixed, and then the resultant was extruded at 250°C using a 40 mm diameter single-screw extruder (model VS40-28, manufactured by Tanabe Plastics). Machinery Co., Ltd., equipped with a full-blade screw, to obtain pellets. The resulting pellets had an MFR of 11 g / 10 minutes.

[0129] The resulting pellets were melt-extruded in the same manner as Example 4 to obtain a 30 µm thick film. The MFR, haze, gloss, Young's modulus, and appearance evaluation of the resulting film are shown in Table 2. [Comparison Example 9]

[0130] Pellets were obtained in the same manner as Example 4, except that the propylene-based copolymer was changed to PP-IX. The resulting pellets had an MFR of 10 g / 10 minutes.

[0131] The resulting pellets were melt-extruded in the same manner as Example 4 to obtain a 30 µm thick film. The MFR, haze, gloss, Young's modulus, and appearance evaluation of the resulting film are shown in Table 2. [Comparison Example 10]

[0132] Pellets were obtained in the same manner as Example 4, except that the propylene-based copolymer was changed to PP-X. The resulting pellets had an MFR of 6.8 g / 10 minutes.

[0133] The resulting pellets were melt-extruded in the same manner as Example 4 to obtain a 30 µm thick film. The MFR, haze, gloss, Young's modulus, and appearance evaluation of the resulting film are shown in Table 2. Table 1 Component (Λ) Component (B) [η]B / [η]A MFR (g / 10 min) [η]A dL / g [η]B dL / g E B Weight % P B % by weight Example 1 1,56 2,58 54 24 1,7 5,1 Example 2 1,56 2,37 62 22 1,5 5,0 Example 3 1,56 2,42 73 21 1,6 5,6 Comparison example 1 1,56 3,84 72 21 2,5 3,6 Comparison example 2 1,39 3,01 77 19 2,2 11 Comparison example 3 2,30 2,30 72 21 1,0 1,4 Example 7 1,48 2,68 53 19 1,8 8,6 Example 8 1,48 2,47 74 17 1,7 9,3 Comparison example 7 1,48 2,11 38 16 1,4 10 Comparison example 8 1,56 1,68 76 17 1,1 7,2 * Examples 1 and 7 have a content of a structural unit derived from ethylene of less than wt.% in component (B) and are therefore to be regarded as reference examples. Table 2 Examples and comparison examples MFR (g / 10 min) MFR ratio before and after melt kneading Turbidity (%) Gloss (%) Young's modulus in MD (MPa) Appearance (fisheye / 100 cm 2 ) Example 4 5,0 1,0 80 7 640 18 Example 5 5,3 1,1 83 6 630 15 Example 6 5,4 1,0 84 6 660 7 Comparison example 4 4,0 1,1 88 6 620 203 Comparison example 5 9,0 0,8 85 6 610 861 Comparison example 6 1,4 1,0 57 16 740 519 Example 9 8,8 1,0 72 9 710 8 Example 10 11 1,2 79 8 710 5 Comparison example 9 10 1,0 61 12 720 5 Comparison example 10 6,8 0,9 40 27 820 2 * Examples 4 and 9 have a content of a structural unit derived from ethylene of less than wt.% in component (B) and are therefore to be regarded as reference examples

[0134] The films of Examples 4 to 6 and Examples 9 to 10 of the present invention were excellent over the films of Comparative Examples 4 and 5 in Young's modulus in the machine direction and in the evaluation of appearance, and the films of Comparative Examples 6, 9 and 10 did not have a haze value suitable as a matte film.

Claims

[1] A propylene-based copolymer composed of 60 to 90 wt% of component (A) which is a polymer component whose main structural unit is a structural unit derived from propylene, and 10 to 40 wt% of component (B) which is a propylene-ethylene copolymer component whose content of an ethylene-derived structural unit is 55 to 80 wt%, the total of component (A) and component (B) being 100 wt%, wherein the ratio of the intrinsic viscosity of component (B) ([η]B) to the intrinsic viscosity of component (A) ([η]A) ([η]B / [η]A) satisfies a formula of 1.3 < [η]B / [η]A ≤ 2.0, and the melt flow rate, measured at a temperature of 230°C and a load of 21.18 N, of the copolymer is not less than 5 g / 10 minutes and not more than 30 g / 10 minutes. [2] Use of the propylene-based copolymer according to claim 1 in the production of a film. [3] The use according to claim 2, wherein the film is an unstretched film. [4] The use according to claim 2 or 3, wherein the film has a haze of 60% or more. [5] The use according to any one of claims 2 to 4, wherein the film is a matte film.