JP7793641B2 - Unstretched film made of propylene polymer composition - Google Patents

Description

The present invention relates to an unstretched film made of a propylene polymer composition and a laminate containing the film.

Polyolefins (olefin polymers), such as polyethylene and polypropylene, require little energy to produce, are lightweight, and are highly recyclable. As a result, they are attracting increasing attention in various industries as they work toward the 3Rs (Reduce, Reuse, Recycle) to create a recycling-oriented society. Polyolefins are used in a variety of fields, including everyday items, kitchen utensils, packaging films, home appliances, machine parts, electrical parts, and automotive parts.

Among olefin polymers, polypropylene has excellent rigidity and heat resistance, but is inferior to polyethylene in cold resistance and impact resistance. Therefore, various propylene polymer compositions have been proposed as a method of improving the physical properties of molded articles such as films obtained from polypropylene (see, for example, Patent Documents 1 to 4).

In addition, many methods have been proposed for improving the physical properties, such as rigidity and transparency, of unstretched films made from propylene polymer compositions (see, for example, Patent Documents 5 to 7).

International Publication No. 1999/007752 International Publication No. 2005/097842 Japanese Patent Application Laid-Open No. 2001-302858 Japanese Patent Application Laid-Open No. 2006-045446 Japanese Patent Application Laid-Open No. 2002-265712 Japanese Patent Application Laid-Open No. 2005-320359 JP 2011-236357 A

As mentioned above, unstretched polypropylene film has an excellent balance of rigidity and heat resistance, but compared to biaxially oriented polypropylene film and biaxially oriented polyethylene terephthalate film, which are commonly used as base materials, its rigidity may not be sufficient depending on the application.

The object of the present invention is to obtain an unstretched film with further improved rigidity.

That is, the present invention relates to the following [1] to [10].

[1]
The polymer contains 20 to 50 mass% of a propylene polymer (a1) having an intrinsic viscosity [η] of 10 to 12 dl/g as measured in tetralin at 135°C, and 50 to 80 mass% of a propylene polymer (a2) having an intrinsic viscosity [η] of 0.5 to 1.5 dl/g as measured in tetralin at 135°C (wherein the total amount of (a1) and (a2) is 100 mass%). and 60 to 99 mass% of a propylene homopolymer (B) selected from propylene homopolymers (B1) having a melt flow rate (MFR) of more than 10 g/10 min and not more than 40 g/10 min, as measured in accordance with JIS K 7210 at a temperature of 230°C and a load of 2.16 kg, or propylene homopolymers (B2) having a ratio (Mw/Mn) of weight average molecular weight (Mw) to number average molecular weight (Mn) of less than 4.0 (wherein the total amount of (A) and (B) is taken as 100 mass%).

[2]
Item [1]. The non-stretched film according to item [1], wherein the propylene polymer composition is a composition containing 1 to 20% by mass of the propylene polymer (A) and 80 to 99% by mass of the propylene homopolymer (B1).

[3]
Item [1]. The non-stretched film according to item [1], wherein the propylene polymer composition is a composition containing 15 to 40% by mass of the propylene polymer (A) and 60 to 85% by mass of the propylene homopolymer (B2).

[4]
Item [1]. The non-oriented film according to Item [1], wherein the propylene polymer (A) is a polymer having a melt flow rate (MFR) measured in accordance with JIS K 7210 at a temperature of 230°C and a load of 2.16 kg in the range of 0.01 to 5 g/10 min, and a melt tension measured at 230°C in the range of 5 to 30 g/10 min.

[5]
Item [1]. The non-stretched film according to Item [1], wherein the propylene polymer (A) is a polymer in which a proportion of an area of a high molecular weight region having a molecular weight of 1,500,000 or more to a total area enclosed by a molecular weight distribution curve measured by gel permeation chromatography (GPC) is 7% or more.

[6]
Item [1]. The non-stretched film according to Item [1], wherein the propylene polymer (A) is a polymer whose molecular weight distribution curve measured by GPC has two peaks, and the ratio (MH/ML) of the molecular weight of the peak on the higher molecular weight side (MH) to the molecular weight of the peak on the lower molecular weight side (ML) is 50 or more.

[7]
Item [1] The non-stretched film according to item [1], wherein the propylene polymer (A) is a polymer having a molecular weight (ML) of 100,000 or less at a peak on the low molecular weight side of a molecular weight distribution curve measured by GPC.

[8]
[6] The non-stretched film according to any one of [1] to [6], wherein the propylene homopolymer (B1) is a polymer having a ratio (Mw/Mn) of weight average molecular weight (Mw) to number average molecular weight (Mn) in the range of 4.0 to 8.0.

[9]
The non-stretched film according to item [1], characterized in that the non-stretched film has a tensile modulus in the machine direction of 2400 MPa or more and a haze measured in accordance with ASTM D-1003 (JIS K7105) of 10% or less.

[10]
A laminate comprising the unstretched film according to any one of items [1] to [9].

The unstretched film of the present invention has good transparency and rigidity, and can be used as a packaging film in a wide range of packaging fields.

The following describes how to implement the present invention.

<Propylene-Based Polymer (A)>
The propylene polymer (A), which is one of the components of the propylene polymer composition forming the non-stretched film of the present invention (hereinafter, sometimes simply referred to as "film"), contains 20 to 50 mass% of a propylene polymer (a1) having an intrinsic viscosity [η] of 10 to 12 dl/g measured in tetralin solvent at 135°C, and 50 to 80 mass% of a propylene polymer (a2) having an intrinsic viscosity [η] of 0.5 to 1.5 dl/g measured in tetralin solvent at 135°C (wherein the total amount of (a1) and (a2) is 100 mass%).

Hereinafter, the intrinsic viscosity [η] measured in tetralin solvent at 135°C will be simply referred to as "intrinsic viscosity [η]".

<Propylene polymer (a1)>
The propylene polymer (a1), which is one of the components contained in the propylene polymer (A) according to the present invention, has an intrinsic viscosity [η] in the range of 10 to 12 dL/g, preferably 10.5 to 11.5 dL/g, and the mass fraction of the propylene polymer (a1) in the propylene polymer (A) is in the range of 20 to 50 mass%, preferably 20 to 45 mass%, more preferably 20 to 40 mass%, and even more preferably 22 to 40 mass%.

Examples of the propylene polymer (a1) according to the present invention include propylene homopolymers and copolymers of propylene and α-olefins having 2 to 8 carbon atoms (excluding propylene). Examples of α-olefins having 2 to 8 carbon atoms include ethylene, 1-butene, 1-hexene, 1-octene, and 4-methyl-1-pentene. Of these α-olefins, ethylene is preferred. One or more α-olefins can be used.

In a copolymer of propylene and an α-olefin having 2 to 8 carbon atoms, the content of structural units derived from propylene is usually 90% by mass or more, preferably 95% by mass or more, and more preferably 98% by mass or more, and the content of structural units derived from an α-olefin having 2 to 8 carbon atoms (excluding propylene) is usually 10% by mass or less, preferably 5% by mass or less, and more preferably 2% by mass or less. The content can be measured by ^C -NMR.

If the intrinsic viscosity [η] of the propylene polymer (a1) exceeds 12 dl/g, film formability tends to be poor and the film surface appearance tends to deteriorate. Furthermore, if the intrinsic viscosity [η] of the propylene polymer (a1) is less than 10 dl/g, the rigidity and heat resistance of the resulting film tend to be insufficient.

If the mass fraction of propylene-based polymer (a1) is less than 20% by mass, the melt tension of the resulting polymer composition will be insufficient, and the rigidity and heat resistance of the resulting film will tend to be insufficient.If it exceeds 50% by mass, this will tend to cause poor appearance when the film is molded.

Propylene-based polymer (a1) can be used alone or in combination with two or more other polymers.

<Propylene polymer (a2)>
The propylene polymer (a2), which is one of the components contained in the propylene polymer (A) according to the present invention, has an intrinsic viscosity [η] in the range of 0.5 to 1.5 dl/g, preferably 0.6 to 1.5 dl/g, and more preferably 0.8 to 1.5 dl/g. The mass fraction of the propylene polymer (a2) in the propylene polymer (A) is in the range of 50 to 80 mass%, preferably 55 to 80 mass%, more preferably 60 to 80 mass%, and even more preferably 60 to 78 mass%.

Examples of the propylene polymer (a2) according to the present invention include propylene homopolymers and copolymers of propylene and α-olefins having 2 to 8 carbon atoms (excluding propylene). Examples of α-olefins having 2 to 8 carbon atoms include ethylene, 1-butene, 1-hexene, 1-octene, and 4-methyl-1-pentene. Of these α-olefins, ethylene is preferred. One or more α-olefins can be used.

In a copolymer of propylene and an α-olefin having 2 to 8 carbon atoms, the content of structural units derived from propylene is usually 90% by mass or more, preferably 93% by mass or more, and more preferably 94% by mass or more, and the content of structural units derived from an α-olefin having 2 to 8 carbon atoms (excluding propylene) is usually 10% by mass or less, preferably 7% by mass or less, and more preferably 6% by mass or less. The content can be measured by ^13C -NMR.

If the intrinsic viscosity [η] of the propylene polymer (a2) is less than 0.5 dl/g, the melt tension of the propylene polymer (A) will be insufficient. On the other hand, if the intrinsic viscosity [η] exceeds 1.5 dl/g, the viscosity will be high and film formability will tend to be poor.

If the mass fraction of propylene-based polymer (a2) is less than 50% by mass, it tends to cause poor appearance during film formation, and if it exceeds 80% by mass, the melt tension of propylene-based polymer (A) becomes insufficient, and the rigidity and heat resistance of the resulting film tend to be insufficient.

Propylene-based polymer (a2) can be used alone or in combination with two or more other polymers.

<Additives>
The propylene polymer (A) according to the present invention may contain additives such as antioxidants, neutralizing agents, flame retardants, and crystal nucleating agents, as needed. One or more additives may be used. The proportion of the additives is not particularly limited and can be adjusted as appropriate.

<Physical Properties of Propylene Polymer (A)>
The propylene polymer (A) according to the present invention has a melt flow rate (MFR) measured at 230°C under a load of 2.16 kg in the range of preferably 0.01 to 5 g/10 min, more preferably 0.05 to 4 g/10 min, and even more preferably 0.1 to 3 g/10 min. When the MFR of the propylene polymer (A) is in the above range, the propylene polymer (A) has excellent film formability.

The propylene polymer (A) according to the present invention preferably has a melt tension (MT) measured at 230°C in the range of 5 to 30 g, more preferably 7 to 25 g, and even more preferably 10 to 20 g. When the MT of the propylene polymer (A) is in the above range, excellent film formability is achieved.

The melt tension (MT) of the propylene polymer (A) in the present invention can be measured using the following equipment and conditions.

- Device: Capillograph 1C (product name) manufactured by Toyo Seiki Co., Ltd.
・Temperature: 230℃
Orifice: L = 8 mm, D = 2.095 mm
The propylene polymer (A) according to the present invention has an area ratio of a high molecular weight region having a molecular weight of 1,500,000 or more (corresponding to the mass ratio of high molecular weight components having a molecular weight of 1,500,000 or more) of preferably 7% or more, more preferably 10% or more, and even more preferably 12% or more of the total area enclosed by a molecular weight distribution curve measured by gel permeation chromatography (GPC). The upper limit of the area ratio is, for example, 30%, preferably 25%.

The fact that the area proportion of the high molecular weight region is equal to or greater than a specific proportion means that the propylene polymer (A) contains high molecular weight components having a molecular weight of 1.5 million or more. At least a portion of these high molecular weight components has an intrinsic viscosity [η] of 10 to 12 dl/g. Therefore, if the proportion of the high molecular weight components is within the above range, the melt tension of the propylene polymer (A) will be superior.

The propylene polymer (A) according to the present invention preferably has a molecular weight distribution curve with two peaks measured by GPC. Here, the ratio (MH/ML) of the peak molecular weight on the high molecular weight side (MH) to the peak molecular weight on the low molecular weight side (ML) is preferably 50 or more, more preferably 70 or more, and even more preferably 90 or more. The upper limit of the ratio (MH/ML) is, for example, 500, preferably 300. A molecular weight distribution curve with two peaks and a MH/ML value equal to or greater than a specific value indicates that the polymer contains a large amount of high-molecular-weight components and has a high intrinsic viscosity [η]. Therefore, such an embodiment of the propylene polymer (A) contributes to improving melt tension and improving the rigidity and heat resistance of a film formed therefrom.

The propylene polymer (A) according to the present invention preferably has a peak molecular weight ML on the low molecular weight side of the molecular weight distribution curve measured by GPC of 100,000 or less, more preferably 80,000 or less, and even more preferably 50,000 or less, from the viewpoints of viscosity and film formability.

<<Method for producing propylene polymer (A)>>
[0033] Examples of methods for producing the propylene polymer (A) according to the present invention include various known production methods. Examples include a method (1) in which a propylene polymer (a1) and a propylene polymer (a2) satisfying the above-mentioned physical properties are produced, and then the propylene polymer (a1) and the propylene polymer (a2) are mixed or melt-kneaded within the above-mentioned ranges to obtain the propylene polymer (A); and a method (2) in which the propylene polymer (a1) and the propylene polymer (a2) satisfying the above-mentioned physical properties are produced in one polymerization system or two or more polymerization systems to obtain the propylene polymer (A).

In method (1), for example, propylene polymer (a1), propylene polymer (a2), and optional additives are mixed using a Henschel mixer, V-blender, tumbler blender, ribbon blender, or the like, followed by melt-kneading using a single-screw extruder, multi-screw extruder, kneader, Banbury mixer, or the like, to obtain a high-quality propylene polymer (A) in which the above components are uniformly dispersed and mixed. The resin temperature during melt-kneading is typically 180 to 280°C, preferably 200 to 260°C.

In method (2), a propylene polymer (A) containing a relatively high molecular weight propylene polymer (a1) and a relatively low molecular weight propylene polymer (a2) can be obtained by two or more multi-stage polymerization. Additives may be added to the obtained propylene polymer (A) as needed.

A preferred method for producing propylene polymer (A) is the above-mentioned method (2), for example, a method in which propylene alone or propylene in combination with other monomers is polymerized in two or more multi-stage polymerization in the presence of a catalyst for producing highly stereoregular polypropylene.

Specifically, in the first polymerization stage, propylene or propylene and an α-olefin having 2 to 8 carbon atoms are polymerized substantially in the absence of hydrogen to produce a relatively high molecular weight propylene polymer (a1) having an intrinsic viscosity [η] of 10 to 12 dl/g, preferably 10.5 to 11.5 dl/g, in an amount of 20 to 50 mass %, preferably 20 to 45 mass %, more preferably 20 to 40 mass %, of the propylene polymer (A), and in the second or subsequent polymerization stages, a relatively low molecular weight propylene polymer (a2) is produced.

The intrinsic viscosity [η] of the relatively low-molecular-weight propylene polymer (a2) produced in the second or subsequent polymerization stages is 0.5 to 1.5 dl/g, preferably 0.6 to 1.5 dl/g, and more preferably 0.8 to 1.5 dl/g. Note that this intrinsic viscosity [η] is the intrinsic viscosity [η] of the propylene polymer produced in that stage alone, and is not the intrinsic viscosity [η] of the entire propylene polymer including the propylene polymers produced in the stages preceding that stage.

In addition, in the second and subsequent polymerization stages, the MFR of the final propylene polymer (A) is adjusted to preferably 0.01 to 5 g/10 min, more preferably 0.05 to 4 g/10 min, and even more preferably 0.1 to 3 g/10 min.

There are no particular restrictions on the method for adjusting the intrinsic viscosity [η] of the propylene polymer produced in the second stage or later, but a method using hydrogen as a molecular weight regulator is preferred.

The production order (polymerization order) of the propylene polymer (a1) and the propylene polymer (a2) is preferably such that, in the first stage, a relatively high molecular weight propylene polymer (a1) is produced substantially in the absence of hydrogen, and then, in the second stage or later, a relatively low molecular weight propylene polymer (a2) is produced, for example, in the presence of hydrogen. While the production order can be reversed, in order to produce a relatively low molecular weight propylene polymer (a2) in the first stage and then a relatively high molecular weight propylene polymer (a1) in the second stage or later, it is necessary to remove as much of the molecular weight modifier, such as hydrogen, contained in the reaction product of the first stage before the start of polymerization in the second stage or later. This makes the polymerization apparatus complex and makes it difficult to increase the intrinsic viscosity [η] in the second stage or later.

The polymerization of each stage in multi-stage polymerization can be carried out continuously or batchwise, but batchwise polymerization is preferred. The propylene polymer (A) containing propylene polymer (a1) and propylene polymer (a2) obtained by batchwise multi-stage polymerization has well-dispersed propylene polymer (a1), which is an ultra-high molecular weight component, resulting in a film with excellent rigidity and heat resistance. Furthermore, when propylene polymer (A) is produced by a continuous multi-stage polymerization method, the residence time distribution can cause compositional variations among polymer particles, resulting in increased fisheyes in the film. However, batchwise polymerization can produce a film with fewer fisheyes. Therefore, by employing a batchwise polymerization method, a film with fewer fisheyes can be obtained, despite the use of a high-molecular-weight propylene polymer (a1).

<Manufacturing conditions>
In producing the propylene polymer (a1) and the propylene polymer (a2), the homopolymerization of propylene or the polymerization of propylene with an α-olefin having 2 to 8 carbon atoms can be carried out by a known method such as slurry polymerization, bulk polymerization, etc. It is also preferable to use a catalyst for producing polypropylene, which will be described later.

The production conditions for propylene polymer (a1) are preferably such that raw material monomers are bulk polymerized in the absence of hydrogen at a polymerization temperature of preferably 20 to 80°C, more preferably 40 to 70°C, and a polymerization pressure of generally atmospheric pressure to 9.8 MPa, preferably 0.2 to 4.9 MPa.

The production conditions for propylene polymer (a2) are preferably such that the raw material monomers are polymerized at a polymerization temperature of preferably 20 to 80°C, more preferably 40 to 70°C, under a polymerization pressure of generally atmospheric pressure to 9.8 MPa, preferably 0.2 to 4.9 MPa, in the presence of hydrogen as a molecular weight regulator.

<Catalyst for polypropylene production>
A catalyst for polypropylene production (hereinafter also simply referred to as "catalyst") that can be used in the production of the propylene polymer (a1), the propylene polymer (a2), and the propylene polymer (A) can be formed from, for example, a solid catalyst component containing magnesium, titanium, and a halogen as essential components, an organometallic compound catalyst component such as an organoaluminum compound, and an electron-donor compound catalyst component such as an organosilicon compound. Representative examples of the catalyst components that can be used include the following:

<Solid catalyst component>
The carrier constituting the solid catalyst component is preferably a carrier obtained from metallic magnesium, an alcohol, and a halogen and/or a halogen-containing compound.

Metallic magnesium can be in the form of granules, ribbons, powder, etc. It is preferable that the magnesium metal does not have a coating such as magnesium oxide on its surface.

It is preferable to use a lower alcohol having 1 to 6 carbon atoms as the alcohol, and using ethanol in particular can produce a support that significantly improves the expression of catalytic performance. The amount of alcohol used is preferably 2 to 100 moles, more preferably 5 to 50 moles, per mole of metallic magnesium. One or more types of alcohol can be used.

The halogen is preferably chlorine, bromine, or iodine, with iodine being preferred. Furthermore, the halogen-containing compound is preferably MgCl ₂ or MgI ₂ . The amount of halogen or halogen-containing compound used is usually 0.0001 gram atom or more, preferably 0.0005 gram atom or more, and more preferably 0.001 gram atom or more, per gram atom of metallic magnesium. One or more types of halogen and halogen-containing compound can be used.

One method for obtaining a carrier by reacting metallic magnesium with an alcohol and a halogen and/or halogen-containing compound is to react metallic magnesium with an alcohol and a halogen and/or halogen-containing compound under reflux (e.g., about 79°C) until hydrogen gas generation is no longer observed (usually 20 to 30 hours). The reaction is preferably carried out in an inert gas atmosphere such as nitrogen gas or argon gas.

When using the obtained support to synthesize a solid catalyst component, it may be dried, or it may be filtered and washed with an inert solvent such as heptane.

The resulting carrier is nearly granular and has a sharp particle size distribution. Furthermore, even when examining individual particles, the variation in particle size is very small. In this case, it is preferable that the sphericity (S) expressed by the following formula (I) is less than 1.60, especially less than 1.40, and that the particle size distribution index (P) expressed by the following formula (II) is less than 5.0, especially less than 4.0.

S=(E1/E2) ² ...(I)
In formula (I), E1 represents the contour length of the projection of the particle, and E2 represents the perimeter of a circle equal to the projected area of the particle.

P=D90/D10...(II)
In formula (II), D90 refers to the particle diameter corresponding to a mass cumulative fraction of 90%. That is, it indicates that the sum of the masses of particles smaller than the particle diameter represented by D90 is 90% of the total mass of all particles. D10 refers to the particle diameter corresponding to a mass cumulative fraction of 10%.

The solid catalyst component is typically obtained by contacting the support with at least a titanium compound. Contact with the titanium compound may be carried out multiple times. Examples of titanium compounds include those represented by general formula (III):

TiX ¹ _n (OR ¹ ) _4-n ...(III)
In formula (III), X ¹ is a halogen atom, and particularly preferably a chlorine atom; R ¹ is a hydrocarbon group having 1 to 10 carbon atoms, and preferably a linear or branched alkyl group; when there are multiple R ^1s , they may be the same or different; and n is an integer of 0 to 4.

Specific examples of titanium compounds include Ti(O-i-C ₃ H ₇ ) ₄ , Ti(O-C ₄ H ₉ ) ₄ , TiCl(O-C ₂ H ₅ ) ₃ , TiCl(O-i-C ₃ H ₇ ) ₃ , TiCl(O-C ₄ H ₉ ) ₃ , TiCl ₂ (O-C ₄ H ₉ ) ₂ , TiCl ₂ (O-i-C ₃ H ₇ ) ₂ and TiCl ₄ , with TiCl ₄ being preferred.

Two or more titanium compounds can be used.

The solid catalyst component is usually obtained by further contacting the support with an electron donor compound. Examples of electron donor compounds include di-n-butyl phthalate. One or more electron donor compounds can be used.

When contacting the titanium compound and electron donor compound with the support, a halogen-containing silicon compound such as silicon tetrachloride can also be contacted. One or more halogen-containing silicon compounds can be used.

The solid catalyst component can be prepared by known methods. For example, an inert hydrocarbon such as pentane, hexane, heptane, or octane is used as a solvent. The carrier, electron donor compound, and halogen-containing silicon compound are added to the solvent, and the titanium compound is then added while stirring. Typically, 0.01 to 10 moles, preferably 0.05 to 5 moles, of the electron donor compound are added per mole of carrier, calculated as magnesium atoms. Also, 1 to 50 moles, preferably 2 to 20 moles, of the titanium compound are added per mole of carrier, calculated as magnesium atoms. The catalytic reaction is carried out at 0 to 200°C for 5 minutes to 10 hours, preferably at 30 to 150°C for 30 minutes to 5 hours. After the reaction is complete, it is preferable to wash the resulting solid catalyst component with an inert hydrocarbon such as n-hexane or n-heptane.

The solid catalyst component may also be a component obtained by contacting a liquid magnesium compound with a liquid titanium compound in the presence of an electron donor compound. Contact with the liquid titanium compound may be carried out multiple times.

Liquid magnesium compounds can be obtained, for example, by contacting a known magnesium compound with an alcohol, preferably in the presence of a liquid hydrocarbon medium, to form a liquid. Examples of magnesium compounds include magnesium halides such as magnesium chloride and magnesium bromide. Examples of alcohols include aliphatic alcohols such as methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, and 2-ethylhexyl alcohol. Examples of liquid hydrocarbon media include hydrocarbon compounds such as heptane, octane, and decane. The amount of alcohol used to prepare the liquid magnesium compound is typically 1.0 to 25 moles, preferably 1.5 to 10 moles, per mole of magnesium compound. Liquid magnesium compounds can be used singly or in combination.

Examples of liquid titanium compounds include titanium compounds represented by the general formula (III) described above. The amount of liquid titanium compound used per mole of magnesium atom (Mg) contained in the liquid magnesium compound is typically 0.1 to 1,000 moles, preferably 1 to 200 moles. One or more liquid titanium compounds can be used.

Examples of electron donor compounds include dicarboxylic acid ester compounds such as phthalic acid esters, acid anhydrides such as phthalic anhydride, organosilicon compounds such as dicyclopentyldimethoxysilane, dicyclohexyldimethoxysilane, and cyclohexylmethyldimethoxysilane, polyethers, acid halides, acid amides, nitriles, and organic acid esters. The amount of electron donor compound used per mole of magnesium atom (Mg) contained in the liquid magnesium compound is typically 0.01 to 5 moles, and preferably 0.1 to 1 mole. One or more types of electron donor compounds can be used.

The temperature during contact is usually -70 to 200°C, preferably 10 to 150°C.

<Organometallic compound catalyst component>
Among the catalyst components, the organometallic compound catalyst component is preferably an organoaluminum compound, for example, a compound represented by the general formula (IV):

AlR ² _n X ² _3-n ...(IV)
In formula (IV), R ² is an alkyl group, cycloalkyl group or aryl group having 1 to 10 carbon atoms; X ² is a halogen atom or an alkoxy group, preferably a chlorine atom or a bromine atom; and n is an integer of 1 to 3.

Specific examples of organic aluminum compounds include trialkyl aluminum compounds such as trimethyl aluminum, triethyl aluminum, and triisobutyl aluminum, as well as diethyl aluminum monochloride, diisobutyl aluminum monochloride, diethyl aluminum monoethoxide, and ethyl aluminum sesquichloride.

One or more organic aluminum compounds can be used.

The amount of organometallic compound catalyst component used is typically 0.01 to 20 moles, preferably 0.05 to 10 moles, per mole of titanium atom in the solid catalyst component.

<Electron-donating compound component>
Among the catalyst components, the electron donor compound to be supplied to the polymerization system is preferably an organosilicon compound, such as dicyclopentyldimethoxysilane, cyclohexylmethyldimethoxysilane, diethylaminotriethoxysilane, diisopropyldimethoxysilane, or cyclohexylisobutyldimethoxysilane.

One or more organosilicon compounds can be used.

The amount of electron donor compound component used is typically 0.01 to 20 moles, preferably 0.1 to 5 moles, per mole of titanium atom in the solid catalyst component.

<Pretreatment>
The solid catalyst component is preferably subjected to a pretreatment such as prepolymerization before use in polymerization. For example, an inert hydrocarbon such as pentane, hexane, heptane, or octane is used as a solvent, and the solid catalyst component, organometallic compound catalyst component, and, if necessary, an electron donor compound component are added to the solvent, and propylene is supplied with stirring to cause the reaction. Propylene is preferably supplied under a propylene partial pressure higher than atmospheric pressure, and the pretreatment is carried out at 0 to 100°C for 0.1 to 24 hours. After completion of the reaction, the pretreated product is preferably washed with an inert hydrocarbon such as n-hexane or n-heptane.

<Propylene homopolymer (B)>
The propylene homopolymer (B), which is one of the components of the propylene polymer composition forming the non-stretched film of the present invention, is selected from the following propylene homopolymer (B1) or the following propylene homopolymer (B2).

<Propylene homopolymer (B1)>
The propylene homopolymer (B1), which is one of the propylene homopolymers (B) according to the present invention, is a propylene homopolymer having a melt flow rate (MFR) of more than 10 g/10 min and not more than 40 g/10 min, preferably in the range of 15 to 40 g/10 min, measured in accordance with JIS K 7210 at a temperature of 230°C and a load of 2.16 kg.

The propylene homopolymer (B1) of the present invention preferably has a ratio (Mw/Mn) of weight average molecular weight (Mw) to number average molecular weight (Mn) in the range of 4.0 to 8.0, more preferably 4.5 to 6.0.

When the Mw/Mn of propylene homopolymer (B1) is within the above range, the haze of the resulting unstretched film is lower (i.e., higher transparency) and the elastic modulus is higher, thereby achieving both rigidity and transparency in the unstretched film.

Furthermore, if Mw/Mn is above the upper limit, the haze of the resulting unstretched film may be high (i.e., low transparency).

The Mw/Mn of propylene homopolymer (B1) was calculated from the average molecular weight (number average molecular weight Mn, weight average molecular weight Mw) obtained from the molecular weight distribution curve measured by GPC.

<Propylene homopolymer (B2)>
The propylene homopolymer (B2), which is another one of the propylene homopolymers (B) according to the present invention, has a ratio (Mw/Mn) of weight average molecular weight (Mw) to number average molecular weight (Mn) of less than 4.0, preferably in the range of 2.0 to 4.0.

The Mw/Mn of propylene homopolymer (B2) was calculated from the average molecular weight (number average molecular weight Mn, weight average molecular weight Mw) obtained from the molecular weight distribution curve measured by GPC.

The propylene homopolymer (B2) of the present invention typically has a melt flow rate (MFR) measured in accordance with JIS K 7210 at a temperature of 230°C and a load of 2.16 kg in the range of 1 to 40 g/10 min, preferably 5 to 20 g/10 min.

<<Method for producing propylene homopolymer (B)>>
The propylene homopolymer (B) according to the present invention can be produced by homopolymerizing propylene using a catalyst, and commercially available propylene homopolymers (homo-PP) can be used. Examples of the catalyst include the above-mentioned catalyst formed from a solid catalyst component containing magnesium, titanium, and a halogen as essential components, an organometallic compound catalyst component such as an organoaluminum compound, and an electron-donor compound catalyst component such as an organosilicon compound; and a metallocene catalyst using a metallocene compound as one of the catalyst components.

The propylene polymer (A) and the propylene homopolymer (B) according to the present invention may each contain at least one biomass-derived monomer (propylene). The same type of monomer constituting the polymer may be solely biomass-derived monomers, or may contain both biomass-derived monomers and fossil fuel-derived monomers. The biomass-derived monomer is a monomer obtained from any renewable natural raw material or its residue, such as a plant- or animal-derived material, including fungi, yeast, algae, and bacteria, and contains about ^10-12 carbon isotopes as carbon, and has a biomass carbon concentration (pMC) of about 100 (pMC) measured in accordance with ASTM D 6866. The biomass-derived monomer (propylene) can be obtained by a conventionally known method.

It is preferable from the viewpoint of reducing the environmental load that the propylene polymer (A) or propylene homopolymer (B) according to the present invention contain a biomass-derived monomer. If the polymer production conditions, such as the polymerization catalyst and polymerization temperature, are the same, even if the raw olefin contains a biomass-derived olefin, the molecular structure, except for the inclusion of about ^10-12 of 14C isotopes, is the same as that of a propylene polymer or propylene homopolymer made from a fossil fuel-derived monomer. Therefore, the performance is also considered to be unchanged.

From the perspective of reducing environmental impact, it is preferable that the propylene-based polymer (A) or propylene homopolymer (B) of the present invention contain a chemically recycled propylene-derived monomer. The propylene constituting the polymer may consist solely of chemically recycled propylene, or may contain chemically recycled propylene together with fossil fuel-derived propylene and/or biomass-derived propylene. Chemically recycled propylene can be obtained by conventional methods. From the perspective of reducing environmental impact (mainly waste reduction), it is preferable that the propylene homopolymer (A) of the present invention contain chemically recycled propylene. Even if the raw material monomer contains a chemically recycled monomer, the chemically recycled monomer is a monomer obtained by depolymerizing or pyrolyzing polymers such as waste plastics back into monomer units such as propylene, or a monomer produced using such a monomer. Therefore, if the polymer production conditions, such as the polymerization catalyst, polymerization process, and polymerization temperature, are equivalent, the molecular structure will be equivalent to that of a propylene homopolymer made from a fossil fuel-derived monomer. Therefore, performance is also expected to be unchanged.

<Propylene polymer composition>
The propylene polymer composition for forming the non-stretched film of the present invention is a composition containing the propylene polymer (A) in the range of 1 to 40% by mass and the propylene homopolymer (B) in the range of 60 to 99% by mass (where the total amount of (A) and (B) is taken as 100% by mass).

When the above-mentioned propylene homopolymer (B1) is used as the propylene homopolymer (B), which is a component of the propylene polymer composition that forms the unstretched film of the present invention, the composition preferably contains 1 to 20% by mass, more preferably 5 to 20% by mass, of the propylene polymer (A), and 80 to 99% by mass, more preferably 80 to 97% by mass, of the above-mentioned propylene homopolymer (B1) (where the total amount of (A) and (B1) is 100% by mass).

When the above-mentioned propylene homopolymer (B2) is used as the propylene homopolymer (B), which is a component of the propylene polymer composition forming the non-stretched film of the present invention, the composition preferably contains the above-mentioned propylene-based polymer (A) in an amount of 15 to 40% by mass, more preferably 20 to 40% by mass, and the above-mentioned propylene homopolymer (B2) in an amount of 65 to 85% by mass, more preferably 60 to 80% by mass (where the total amount of (A) and (B2) is 100% by mass).

The propylene polymer composition of the present invention contains the above-mentioned propylene polymer (A) and the above-mentioned propylene homopolymer (B), or the above-mentioned propylene homopolymer (B1), or the above-mentioned propylene homopolymer (B2) in amounts within the above-mentioned ranges, making it possible to obtain an unstretched film with good transparency and rigidity (tensile modulus).

If a composition containing propylene polymer (A) in an amount exceeding the upper limit is used, the transparency of the resulting unstretched film may be significantly reduced, and the film may have poor appearance. On the other hand, if the amount of propylene polymer (A) is less than the lower limit, the rigidity (tensile modulus) of the resulting unstretched film may not be improved.

The propylene polymer composition of the present invention preferably has a melt flow rate (MFR) measured in accordance with JIS K 7210 at a temperature of 230°C and a load of 2.16 kg in the range of 1 to 20 g/10 min, preferably 2 to 15 g/10 min, and more preferably 3 to 10 g/10 min. An MFR in the above range provides good formability into an unstretched film, resulting in a film with excellent appearance.

In addition to the propylene polymer (A) and the propylene homopolymer (B), the propylene polymer composition of the present invention may contain additives such as weathering stabilizers, heat stabilizers, antistatic agents, slip agents, antiblocking agents, antifogging agents, nucleating agents, decomposing agents, pigments, dyes, plasticizers, hydrochloric acid absorbers, antioxidants, crosslinking agents, crosslinking accelerators, reinforcing agents, fillers, softeners, processing aids, activators, moisture absorbers, adhesives, flame retardants, and mold release agents, provided that the purpose of the present invention is not impaired. One or more additives may be used.

The propylene polymer composition according to the present invention may contain a nucleating agent to improve transparency, heat resistance, and other properties. Examples of nucleating agents include sorbitol compounds such as dibenzylidene sorbitol, organic phosphate ester compounds, rosinate compounds, and C4 to C12 aliphatic dicarboxylic acids and their metal salts. Of these, organic phosphate ester compounds are preferred.

One or more nucleating agents can be used.

The nucleating agent can be used in an amount of preferably 0.05 to 0.5 parts by mass, more preferably 0.1 to 0.3 parts by mass, per 100 parts by mass of the combined propylene polymer (A) and propylene homopolymer (B).

<Production of Propylene-Based Polymer Composition>
The propylene polymer composition according to the present invention can be produced by employing any known method. Examples of the method include a method of mixing the propylene polymer (A), the propylene homopolymer (B), and, if necessary, other components, using a Henschel mixer, a V-blender, a ribbon blender, a tumbler blender, or the like; and a method of melt-kneading the mixed mixture using a single-screw extruder, a twin-screw extruder, a kneader, a Banbury mixer, a roll, or the like, followed by granulation or pulverization.

<Non-stretched film and laminate>
The non-stretched film of the present invention is formed from the propylene-based polymer composition. The non-stretched film of the present invention exhibits higher rigidity and heat resistance than conventional non-stretched polypropylene films. The non-stretched film is used as a packaging material for, for example, food, beverages, industrial parts, miscellaneous goods, toys, daily necessities, office supplies, medical supplies, etc.

The thickness of the unstretched film of the present invention is usually less than 200 μm, preferably 10 to 150 μm, and more preferably 15 to 100 μm. Because the unstretched film of the present invention has excellent rigidity, it can easily be made thinner.

The unstretched film of the present invention preferably has a tensile modulus in the longitudinal direction of 2500 MPa or more and a haze measured in accordance with ASTM D-1003 (JIS K7105) of 10% or less.

Methods for producing the unstretched film of the present invention include, for example, extrusion molding methods such as the T-die method and inflation method, compression molding methods, calendar molding methods, and casting methods.

The molding of an unstretched film can be carried out, for example, as follows. The components constituting the propylene-based polymer composition may be directly charged into the hopper of a film-molding machine, or the components may be premixed using a ribbon blender, Banbury mixer, Henschel mixer, super mixer, or the like. Alternatively, the components may be melt-kneaded using a kneader such as a single-screw or twin-screw extruder or roll mill to obtain a propylene-based polymer composition, which may then be molded into a film.

A specific example of the production of unstretched film will be explained using the T-die method. The above components are fed into an extruder and melt-kneaded, usually at a temperature of 180 to 280°C, preferably 200 to 270°C, and then extruded into a film from the die lip of the T-die. The molten film is cooled and taken up by a take-up machine such as a nip roll to obtain an unstretched film.

Methods for cooling the molten film include, for example, cooling using rolls and air cooling using the air knife method or air chamber method, narrow pressure cooling using the polishing roll method, swing roll method, belt casting method, etc., and contact cooling using a refrigerant using the water cooling method, etc.

The resulting unstretched film can be subjected to film processing methods commonly used in film molding, such as corona discharge treatment and liquid coating treatment.

The laminate of the present invention has the unstretched film of the present invention.

The laminate may be a laminate containing two or more layers of the non-stretched film of the present invention, or a laminate containing one or more layers of the non-stretched film of the present invention and one or more other layers. By using a laminated structure, it is possible to impart various additional functions to the film. Methods that can be used in this case include co-extrusion and extrusion coating.

Examples of other layers include barrier layers for gases such as water vapor and oxygen, sound-absorbing layers, light-shielding layers, adhesive layers, pressure-sensitive adhesive layers, colored layers, conductive layers, and recycled resin-containing layers. Specific examples of materials for forming other layers include olefin-based polymer compositions other than the propylene-based polymer compositions, gas-barrier resin compositions, and adhesive resin compositions.

The unstretched film and laminate of the present invention can be used as packaging films in a wide range of packaging fields, such as packaging various foods such as fresh foods such as vegetables and fish, dried foods such as snacks and noodles, and watery foods such as soups and pickles; packaging medical products such as medical products in various forms such as tablets, powders, and liquids, and medical peripheral materials; and packaging various electrical equipment such as cassette tapes and electrical components.

The present invention will be explained in more detail below based on examples, but the present invention is not limited to these examples. The various properties of the polymers, polymer compositions, and unstretched films obtained in each example were measured and evaluated as follows:

The polymers used in the examples and comparative examples are shown below.

[Propylene-based polymer (A)]
[Production of Propylene Polymer (A-1)]
[Production Example 1]
[Preparation of magnesium compounds]
A reaction vessel equipped with a stirrer (internal volume: 500 L) was thoroughly purged with nitrogen gas, and 97.2 kg of ethanol, 640 g of iodine, and 6.4 kg of metallic magnesium were charged and reacted under reflux with stirring until no more hydrogen gas was generated from the system, yielding a solid reaction product. The reaction liquid containing this solid reaction product was dried under reduced pressure to obtain the target magnesium compound (support for the solid catalyst).

[Preparation of solid catalyst component]
30 kg of the magnesium compound (unground), 150 L of purified heptane (n-heptane), 4.5 L of silicon tetrachloride, and 5.4 L of di-n-butyl phthalate were added to a reactor equipped with a stirrer (internal volume: 500 L) that had been thoroughly purged with nitrogen gas. The system was maintained at 90°C, and 144 L of titanium tetrachloride was added with stirring. The reaction was carried out at 110°C for 2 hours, after which the solid component was separated and washed with purified heptane at 80°C. Further, 228 L of titanium tetrachloride was added, and the reaction was carried out at 110°C for 2 hours, after which the solid component was thoroughly washed with purified heptane to obtain a solid catalyst component.

[Production of Prepolymerization Catalyst]
To 200 mL of heptane were added 10 mmol of triethylaluminum, 2 mmol of dicyclopentyldimethoxysilane, and 1 mmol of the solid catalyst component obtained above, calculated as titanium atoms. The internal temperature was maintained at 20°C, and propylene was continuously introduced with stirring. After 60 minutes, stirring was stopped, resulting in a prepolymerized catalyst (prepolymerization catalyst) in which 4.0 g of propylene had polymerized per 1 g of solid catalyst.

[Main Polymerization]
A 600-liter autoclave was charged with 336 liters of propylene and heated to 60°C. Then, 8.7 mL of triethylaluminum, 11.4 mL of dicyclopentyldimethoxysilane, and 2.9 g of the prepolymerization catalyst obtained by the above method were charged to initiate polymerization. 75 minutes after the start of polymerization, the temperature was lowered to 50°C over 10 minutes (completion of the first-stage polymerization).

The intrinsic viscosity [η] of the propylene polymer (a1-1) polymerized under the same conditions as in the first stage was 11 dl/g.

After the temperature was lowered, hydrogen was continuously introduced to maintain a constant pressure of 3.3 MPaG, and polymerization was carried out for 151 minutes. The vent valve was then opened, and unreacted propylene was purged via an integrating flow meter (end of second-stage polymerization).

In this way, 51.8 kg of powdery propylene polymer was obtained.

To this propylene polymer, 2000 ppm of Irganox 1010 (manufactured by Ciba Specialty Chemicals Co., Ltd.), 2000 ppm of Irgaphos 168 (manufactured by Ciba Specialty Chemicals Co., Ltd.), and 1000 ppm of Sandstab P-EPQ (manufactured by Clariant Japan Co., Ltd.) were added as antioxidants, and 1000 ppm of calcium stearate was added as a neutralizer. The mixture was melt-kneaded in a twin-screw extruder to obtain pelletized propylene polymer. The MFR of the final propylene polymer (A-1) thus obtained was 1.2 g/10 min. Furthermore, the proportion of propylene polymer (a1-1) produced in the first-stage polymerization in the final propylene polymer (A-1), calculated from mass balance, was 25% by mass.

The composition and physical properties of the obtained propylene polymer (A-1) were measured using the methods described below.

The measurement results are shown in Table 1.

[Propylene homopolymer (B1)]
[Production of Propylene Homopolymer (B1-1)]
[Production Example 2]
[Preparation of solid titanium catalyst component (a-1)]
95.2 g of anhydrous magnesium chloride, 442 ml of decane, and 390.6 g of 2-ethylhexyl alcohol were subjected to a heating reaction at 130°C for 2 hours to obtain a homogeneous solution, and then 21.3 g of phthalic anhydride was added to this solution, followed by stirring and mixing at 130°C for another 1 hour to dissolve the phthalic anhydride.

The homogeneous solution thus obtained was cooled to room temperature, and then 75 ml of this homogeneous solution was added dropwise over one hour to 200 ml of titanium tetrachloride maintained at -20°C. After the addition was complete, the temperature of this mixture was raised to 110°C over four hours. When it reached 110°C, 5.22 g of diisobutyl phthalate (DIBP) was added, and the mixture was stirred at the same temperature for two hours.

After the 2-hour reaction, the solid was collected by hot filtration, resuspended in 275 ml of titanium tetrachloride, and heated again at 110°C for 2 hours. After the reaction was complete, the solid was collected again by hot filtration and thoroughly washed with decane and hexane at 110°C until no free titanium compounds were detected in the solution.

The solid titanium catalyst component prepared as described above was stored as a hexane slurry, and a portion of this was dried to examine the catalyst composition. The solid titanium catalyst component contained 2.3% by mass of titanium, 61% by mass of chlorine, 19% by mass of magnesium, and 12.5% by mass of DIBP.

[Production of prepolymerization catalyst (b-1)]
100.0 g of solid titanium catalyst component (a-1), 19.2 ml of cyclohexylmethyldimethoxysilane, 65.6 mL of triethylaluminum, and 10 L of heptane were charged into a 20 L autoclave equipped with a stirrer, and 600 g of propylene was charged while maintaining the internal temperature at 15 to 20°C, and the reaction was carried out with stirring for 100 minutes. After completion of polymerization, the solid component was allowed to settle, and the supernatant was removed and washed with heptane twice. The obtained prepolymerized catalyst was resuspended in purified heptane and adjusted with heptane so that the solid catalyst component concentration was 1.0 g/L.

[Production of Propylene Homopolymer (B1-1)]
Propylene was continuously supplied at 43 kg/hour, hydrogen at 56 NL/hour, prepolymerization catalyst (b-1) at 0.77 g/hour, triethylaluminum at 2.3 mL/hour, and cyclohexylmethyldimethoxysilane at 4.3 mL/hour to a tubular polymerization reactor having an internal volume of 58 L, and polymerization was carried out in a liquid-filled state in the absence of a gas phase. The temperature of the tubular polymerization reactor was 70°C, and the pressure was 3.4 MPa/G.

The resulting slurry was sent to a 70 L vessel polymerization reactor equipped with a stirrer, where further polymerization was carried out. Propylene was supplied to the polymerization reactor at 45 kg/h, and hydrogen was supplied so that the hydrogen concentration in the gas phase reached 4.3 mol%. Polymerization was carried out at a polymerization temperature of 70°C and a pressure of 3.1 MPa/G.

The resulting slurry was deactivated, and the propylene was evaporated to obtain a powdery propylene polymer (resin a). The resulting propylene homopolymer (B1-1) had an MFR of 15 g/10 min and an Mw/Mn of 5.0.

[Production of Propylene Homopolymer (B1-2)]
[Production Example 3]
[Preparation of solid titanium catalyst component (a-1)]
95.2 g of anhydrous magnesium chloride, 442 ml of decane, and 390.6 g of 2-ethylhexyl alcohol were subjected to a heating reaction at 130°C for 2 hours to obtain a homogeneous solution, and then 21.3 g of phthalic anhydride was added to this solution, followed by stirring and mixing at 130°C for another 1 hour to dissolve the phthalic anhydride.

The homogeneous solution thus obtained was cooled to room temperature, and then 75 ml of this homogeneous solution was added dropwise over one hour to 200 ml of titanium tetrachloride maintained at -20°C. After the addition was complete, the temperature of this mixture was raised to 110°C over four hours. When it reached 110°C, 5.22 g of diisobutyl phthalate (DIBP) was added, and the mixture was stirred at the same temperature for two hours.

After the 2-hour reaction, the solid was collected by hot filtration, resuspended in 275 ml of titanium tetrachloride, and heated again at 110°C for 2 hours. After the reaction was complete, the solid was collected again by hot filtration and thoroughly washed with decane and hexane at 110°C until no free titanium compounds were detected in the solution.

The solid titanium catalyst component prepared as described above was stored as a hexane slurry, and a portion of this was dried to examine the catalyst composition. The solid titanium catalyst component contained 2.3 wt% titanium, 61 wt% chlorine, 19 wt% magnesium, and 12.5 wt% DIBP.

[Production of prepolymerization catalyst (b-2)]
100.0 g of solid titanium catalyst component (a-1), 22.4 ml of dicyclopentyldimethoxysilane, 65.6 mL of triethylaluminum, and 10 L of heptane were charged into a 20 L autoclave equipped with a stirrer, and 600 g of propylene was charged while maintaining the internal temperature at 15 to 20°C, and the reaction was carried out with stirring for 100 minutes. After completion of polymerization, the solid component was allowed to settle, and the supernatant was removed and washed with heptane twice. The obtained prepolymerized catalyst was resuspended in purified heptane and adjusted with heptane so that the solid catalyst component concentration was 1.0 g/L.

[Production of Propylene Homopolymer (B1-2)]
Propylene was continuously supplied at 43 kg/hour, hydrogen at 163 NL/hour, prepolymerization catalyst (b-2) at 0.55 g/hour, triethylaluminum at 1.9 mL/hour, and dicyclopentyldimethoxysilane at 3.8 mL/hour to a tubular polymerization reactor having an internal volume of 58 L, and polymerization was carried out in a liquid-filled state in the absence of a gas phase. The temperature of the tubular polymerization reactor was 70°C, and the pressure was 3.5 MPa/G.

The resulting slurry was sent to a 70 L vessel polymerization reactor equipped with a stirrer, where further polymerization was carried out. Propylene was supplied to the polymerization reactor at 45 kg/h, and hydrogen was supplied so that the hydrogen concentration in the gas phase reached 15.8 mol%. Polymerization was carried out at a polymerization temperature of 63°C and a pressure of 3.2 MPa/G.

The resulting slurry was deactivated, and the propylene was evaporated to obtain a powdery propylene polymer (resin b). The resulting propylene homopolymer (B1-2) had an MFR of 30 g/10 min and an Mw/Mn of 5.2.

[Production of Propylene Homopolymer (D-1)]
[Production Example 4]
[Preparation of solid titanium catalyst component (a-1)]
95.2 g of anhydrous magnesium chloride, 442 ml of decane, and 390.6 g of 2-ethylhexyl alcohol were subjected to a heating reaction at 130°C for 2 hours to obtain a homogeneous solution, and then 21.3 g of phthalic anhydride was added to this solution, followed by stirring and mixing at 130°C for another 1 hour to dissolve the phthalic anhydride.

The homogeneous solution thus obtained was cooled to room temperature, and then 75 ml of this homogeneous solution was added dropwise over one hour to 200 ml of titanium tetrachloride maintained at -20°C. After the addition was complete, the temperature of this mixture was raised to 110°C over four hours. When it reached 110°C, 5.22 g of diisobutyl phthalate (DIBP) was added, and the mixture was stirred at the same temperature for two hours.

After the 2-hour reaction, the solid was collected by hot filtration, resuspended in 275 ml of titanium tetrachloride, and heated again at 110°C for 2 hours. After the reaction was complete, the solid was collected again by hot filtration and thoroughly washed with decane and hexane at 110°C until no free titanium compounds were detected in the solution.

The solid titanium catalyst component prepared as described above was stored as a hexane slurry, and a portion of this was dried to examine the catalyst composition. The solid titanium catalyst component contained 2.3 wt% titanium, 61 wt% chlorine, 19 wt% magnesium, and 12.5 wt% DIBP.

[Production of prepolymerization catalyst (b-1)]
100.0 g of solid titanium catalyst component (a-1), 19.2 ml of cyclohexylmethyldimethoxysilane, 65.6 mL of triethylaluminum, and 10 L of heptane were charged into a 20 L autoclave equipped with a stirrer, and 600 g of propylene was charged while maintaining the internal temperature at 15 to 20°C, and the reaction was carried out with stirring for 100 minutes. After completion of polymerization, the solid component was allowed to settle, and the supernatant was removed and washed with heptane twice. The obtained prepolymerized catalyst was resuspended in purified heptane and adjusted with heptane so that the solid catalyst component concentration was 1.0 g/L.

[Production of Propylene Homopolymer (D-1)]
Propylene was continuously supplied at 43 kg/hour, hydrogen at 56 NL/hour, prepolymerization catalyst (b-1) at 0.77 g/hour, triethylaluminum at 2.3 mL/hour, and cyclohexylmethyldimethoxysilane at 4.3 mL/hour to a tubular polymerization reactor having an internal volume of 58 L, and polymerization was carried out in a liquid-filled state in the absence of a gas phase. The temperature of the tubular polymerization reactor was 70°C, and the pressure was 3.4 MPa/G.

The resulting slurry was sent to a 70 L vessel polymerization reactor equipped with a stirrer, where further polymerization was carried out. Propylene was supplied to the polymerization reactor at 45 kg/h, and hydrogen was supplied so that the hydrogen concentration in the gas phase was 2.9 mol%. Polymerization was carried out at a polymerization temperature of 70°C and a pressure of 3.1 MPa/G.

The resulting slurry was deactivated, and the propylene was evaporated to obtain a powdery propylene homopolymer (D-1). The resulting propylene homopolymer (D-1) had an MFR of 9 g/10 min and an Mw/Mn ratio of 5.0.

[Propylene homopolymer (D-2)]
As the propylene homopolymer (D-2), a propylene homopolymer having an MFR of 6.5 g/10 min and an Mw/Mn of 5.2 (manufactured by Prime Polymer Co., Ltd., trade name: Prime Polypro F-704NP) was used.

[Propylene homopolymer (D-3)]
As the propylene homopolymer (D-3), a propylene homopolymer having an MFR of 7.2 g/10 min and an Mw/Mn of 4.8 (manufactured by Prime Polymer Co., Ltd., trade name: Prime Polypro F107BA) was used.

[Fraction of each component in propylene polymer (A)]
In Production Example 1, the mass fractions of the propylene polymer obtained in the first stage (corresponding to the propylene polymer (a1)) and the propylene polymer obtained in the second stage (corresponding to the propylene polymer (a2)) were determined from the amount of reaction heat generated during polymerization.

[Intrinsic viscosity [η]]
The intrinsic viscosity [η] (dl/g) was measured in tetralin solvent at 135° _C. The intrinsic viscosity [η] of the propylene polymer obtained in the second stage (corresponding to the propylene polymer (a2)) was calculated from the following formula:

[η] ₂ = ([η] _total ×100−[η] ₁ ×W ₁ )/W ₂
[η] _total : intrinsic viscosity of the entire propylene polymer [η] ₁ : intrinsic viscosity of the propylene polymer obtained in the first stage W ₁ : mass fraction (%) of the propylene polymer obtained in the first stage
W ₂ : Mass fraction (%) of the propylene polymer obtained in the second stage
[Melt flow rate]
The melt flow rate (MFR) (g/10 min) was measured in accordance with JIS-K7210 at a measurement temperature of 230° C. and a load of 2.16 kgf.

[Proportion of high molecular weight region with a molecular weight of 1.5 million or more, ML, MH/ML, molecular weight distribution]
The proportion of the high molecular weight region having a molecular weight of 1.5 million or more is the area proportion of the high molecular weight region having a molecular weight of 1.5 million or more to the total area enclosed by the molecular weight distribution curve (specifically, the molecular weight distribution curve and the horizontal axis) measured by GPC using the following equipment and conditions. Here, the horizontal axis represents the molecular weight (logarithmic value), and the vertical axis represents dw/dLog(M) [w: cumulative mass fraction, M: molecular weight]. The peak molecular weight MH on the high molecular weight side and the peak molecular weight ML on the low molecular weight side of the molecular weight distribution curve were obtained, and MH/ML was calculated. Furthermore, the average molecular weight (number average molecular weight Mn, weight average molecular weight Mw) was obtained from the molecular weight distribution curve, and the molecular weight distribution (Mw/Mn) was calculated.

[GPC measurement device]
Gel permeation chromatograph HLC-8321 GPC/HT type (Tosoh Corporation) Analysis equipment Data processing software Empower 3 (Waters Corporation) Measurement conditions Column: TSKgel GMH6-HT x 2 + TSKgel GMH6-HTL x 2
(Both 7.5mm I.D. x 30cm, manufactured by Tosoh Corporation)
Column temperature: 140°C
Mobile phase: o-dichlorobenzene (containing 0.025% BHT)
Detector: Differential refractometer Flow rate: 1.0 mL/min
Sample concentration: 0.1% (w/v)
Injection volume: 0.4mL
Sampling time interval: 1s
Column calibration: Monodisperse polystyrene (Tosoh Corporation)
Molecular weight conversion: PP conversion/general calibration method (PS (polystyrene) viscosity conversion coefficient K _PS = 0.000138 dl/g,
α _PS = 0.700, viscosity conversion factor for PP (polypropylene) K _PP = 0.000242 dl/g, α _PP = 0.707)
The physical properties of the unstretched films obtained using the compositions obtained in the Examples and Comparative Examples were measured by the following methods.

[Hayes]
Measurement was carried out in accordance with ASTM D-1003 (JIS K7105).

[Film elastic modulus]
The tensile modulus (MPa) was measured according to the method of JIS K7161. The measurement was carried out at 23°C in the extrusion direction (MD) of molding and in the direction perpendicular to the MD (TD). It can be said that the higher the tensile modulus, the higher the rigidity.

Comparative Example 1
The propylene homopolymer (B1-1) obtained in Production Example 2 was used alone as the propylene polymer composition. The propylene homopolymer (B1-1) was extruded into a film using a film molding machine equipped with a T-die having a width of 600 mm at the tip of an extruder having a screw diameter of 75 mm and set at a temperature of 286°C, and the film was then cooled with a chill roll set at a temperature of 30°C to obtain an unstretched film having a thickness of 25 μm.

The physical properties of the obtained unstretched film were measured using the methods described above.

The results are shown in Table 2.

Example 1
An unstretched film was obtained in the same manner as in Comparative Example 1, except that a propylene polymer composition comprising 10 parts by mass of the propylene polymer (A-1) obtained in Production Example 1 and 90 parts by mass of the propylene homopolymer (B1-1) obtained in Production Example 2 was used instead of the propylene polymer composition used in Comparative Example 1.

The physical properties of the obtained unstretched film were measured using the methods described above.

The results are shown in Table 2.

Example 2
An unstretched film was obtained in the same manner as in Example 1, except that a propylene polymer composition comprising 20 parts by mass of a propylene polymer (A-1) and 80 parts by mass of a propylene homopolymer (B1-1) was used instead of the propylene polymer composition used in Example 2.

The physical properties of the obtained unstretched film were measured using the methods described above.

The results are shown in Table 2.

Comparative Example 2
An unstretched film was obtained in the same manner as in Comparative Example 1, except that the propylene homopolymer (B1-1) used in Comparative Example 1 was replaced with the propylene homopolymer (B1-2) obtained in Production Example 3.

The physical properties of the obtained unstretched film were measured using the methods described above.

The results are shown in Table 2.

Example 3
An unstretched film was obtained in the same manner as in Example 1, except that the propylene homopolymer (B1-1) used in Example 1 was replaced with the propylene homopolymer (B1-2).

The physical properties of the obtained unstretched film were measured using the methods described above.

The results are shown in Table 2.

Example 4
An unstretched film was obtained in the same manner as in Example 2, except that the propylene homopolymer (B1-1) used in Example 2 was replaced with the propylene homopolymer (B1-2).

The physical properties of the obtained unstretched film were measured using the methods described above.

The results are shown in Table 2.

Comparative Examples 3 to 5
The same procedure as in Comparative Example 1 was carried out except that the propylene polymer composition used contained the propylene polymer (A-1) and the propylene homopolymer (D-2) in the amounts shown in Table 3, to obtain an unstretched film.

The physical properties of the obtained unstretched film were measured using the methods described above.

The results are shown in Table 3.

Comparative Examples 6 and 7
The same procedure as in Comparative Example 1 was carried out except that the propylene polymer composition used contained the propylene polymer (A-1) and the propylene homopolymer (D-3) in the amounts shown in Table 3, to obtain an unstretched film.

The physical properties of the obtained unstretched film were measured using the methods described above.

The results are shown in Table 3.

[Comparative Examples 8 and 9]
The same procedure as in Comparative Example 1 was carried out except that the propylene polymer composition used contained the propylene polymer (A-1) and the propylene homopolymer (D-1) in the amounts shown in Table 3, to obtain an unstretched film.

The physical properties of the obtained unstretched film were measured using the methods described above.

The results are shown in Table 3.

[Propylene homopolymer (B2)]
[Production of Propylene Homopolymer (B2-1)]
[Production Example 5]
[Preparation of solid titanium catalyst component (a-1)]
95.2 g of anhydrous magnesium chloride, 442 ml of decane, and 390.6 g of 2-ethylhexyl alcohol were subjected to a heating reaction at 130°C for 2 hours to obtain a homogeneous solution, and then 21.3 g of phthalic anhydride was added to this solution, followed by stirring and mixing at 130°C for another 1 hour to dissolve the phthalic anhydride.

After the 2-hour reaction, the solid was collected by hot filtration, resuspended in 275 ml of titanium tetrachloride, and heated again at 110°C for 2 hours. After the reaction was complete, the solid was collected again by hot filtration and thoroughly washed with decane and hexane at 110°C until no free titanium compounds were detected in the solution.

The solid titanium catalyst component prepared as described above was stored as a hexane slurry, and a portion of this was dried to examine the catalyst composition. The solid titanium catalyst component contained 2.3% by mass of titanium, 61% by mass of chlorine, 19% by mass of magnesium, and 12.5% by mass of DIBP.

[Production of prepolymerization catalyst (b-2)]
100.0 g of solid titanium catalyst component (a-1), 22.4 ml of dicyclopentyldimethoxysilane, 65.6 mL of triethylaluminum, and 10 L of heptane were charged into a 20 L autoclave equipped with a stirrer, and 600 g of propylene was charged while maintaining the internal temperature at 15 to 20°C, and the reaction was carried out with stirring for 100 minutes. After completion of polymerization, the solid component was allowed to settle, and the supernatant was removed and washed with heptane twice. The obtained prepolymerized catalyst was resuspended in purified heptane and adjusted with heptane so that the solid catalyst component concentration was 1.0 g/L.

[Production of Propylene Homopolymer (B2-1)]
Propylene was continuously supplied at 43 kg/hour, hydrogen at 40 NL/hour, prepolymerization catalyst (b-2) at 0.65 g/hour, triethylaluminum at 2.1 mL/hour, and dicyclopentyldimethoxysilane at 4.4 mL/hour to a tubular polymerization reactor having an internal volume of 58 L, and polymerization was carried out in a liquid-filled state in the absence of a gas phase. The temperature of the tubular polymerization reactor was 70°C, and the pressure was 3.2 MPa/G.

The resulting slurry was sent to a 70 L vessel polymerization reactor equipped with a stirrer, where further polymerization was carried out. Propylene was supplied to the polymerization reactor at 45 kg/h, and hydrogen was supplied so that the hydrogen concentration in the gas phase was 2.4 mol%. Polymerization was carried out at a polymerization temperature of 70°C and a pressure of 2.9 MPa/G.

The resulting slurry was deactivated, and the propylene was evaporated to obtain a powdery propylene homopolymer. The resulting propylene polymer had an MFR of 3.0 g/10 min.

To 100 parts by mass of the resulting propylene polymer, 0.06 parts by mass of organic peroxide (trade name: Perhexa 25B-40 (manufactured by NOF Corporation)) was added and thoroughly stirred. This mixture was melt-kneaded using a KTX 30mm twin-screw extruder manufactured by Kobe Steel, Ltd., at a cylinder temperature of 230°C and an extrusion rate of 25 kg/hr. The resulting propylene homopolymer (B2-1) had an MFR of 9 g/10 min and an Mw/Mn of 3.8.

[Production of Propylene Homopolymer (B2-2)]
[Production Example 6]
[Preparation of solid titanium catalyst component (a-2)]
A vibration mill equipped with four grinding pots, each with an internal volume of 4 L and containing 9 kg of 12 mm diameter steel balls, was prepared. 300 g of magnesium chloride, 115 mL of diisobutyl phthalate, and 60 mL of titanium tetrachloride were added to each pot in a nitrogen atmosphere, and the mixture was ground for 40 hours.

75 g of the above co-ground product was placed in a 5 L flask, 1.5 L of toluene was added, and the mixture was stirred at 114°C for 30 minutes, then allowed to stand and the supernatant liquid was removed. The solids were then washed three times with 1.5 L of n-heptane at 20°C and dispersed in an additional 1.5 L of n-heptane to form a transition metal catalyst component slurry. The resulting transition metal catalyst component (a-2) contained 2 mass% titanium and 18 mass% diisobutyl phthalate.

[Production of prepolymerization catalyst (b-3)]
100 g of the transition metal catalyst component (a-2), 15.4 mL of triethylaluminum, and 100 L of heptane were charged into a 200 L autoclave equipped with a stirrer, and 600 g of propylene was added while maintaining the internal temperature at 5°C, and the reaction was carried out with stirring for 60 minutes. After completion of the polymerization, 4.1 mL of titanium tetrachloride was charged to prepare a prepolymerization catalyst (b-3). This prepolymerization catalyst (b-3) contained 6 g of propylene homopolymer per 1 g of the transition metal catalyst component.

[Production of Propylene Homopolymer (B2-2)]
To a 500 L stirred vessel polymerization reactor were continuously supplied propylene at 130 kg/h, hydrogen at 136 NL/h, prepolymerization catalyst (b-3) at 1.05 g/h, triethylaluminum at 5.2 mL/h, and cyclohexylmethyldimethoxysilane at 0.4 mL/h, and hydrogen was supplied so that the hydrogen concentration in the gas phase was 2.6 mol%. The temperature of the stirred vessel polymerization reactor was 73°C, and the pressure was 3.2 MPa/G.

The resulting slurry was deactivated, and the propylene was evaporated to obtain a powdery propylene homopolymer. The resulting propylene homopolymer had an MFR of 1.7 g/10 min.

To 100 parts by mass of the resulting propylene homopolymer, 0.07 parts by mass of organic peroxide (trade name Perhexa 25B-40 (manufactured by NOF Corporation)) was added and thoroughly stirred. This mixture was melt-kneaded using a KTX 30mm twin-screw extruder manufactured by Kobe Steel, Ltd., at a cylinder temperature of 230°C and an extrusion rate of 25 kg/h. The resulting propylene homopolymer (B2-2) had an MFR of 9 g/10 min and an Mw/Mn of 3.7.

[Production of Propylene Homopolymer (D2-1)]
[Production Example 7]
[Preparation of solid titanium catalyst component (a-1)]
95.2 g of anhydrous magnesium chloride, 442 ml of decane, and 390.6 g of 2-ethylhexyl alcohol were subjected to a heating reaction at 130°C for 2 hours to obtain a homogeneous solution, and then 21.3 g of phthalic anhydride was added to this solution, followed by stirring and mixing at 130°C for another 1 hour to dissolve the phthalic anhydride.

The homogeneous solution thus obtained was cooled to room temperature, and then 75 ml of this homogeneous solution was added dropwise over one hour to 200 ml of titanium tetrachloride maintained at -20°C. After the addition was complete, the temperature of this mixture was raised to 110°C over four hours. When it reached 110°C, 5.22 g of diisobutyl phthalate (DIBP) was added, and the mixture was stirred at the same temperature for two hours.

After the 2-hour reaction, the solid was collected by hot filtration, resuspended in 275 ml of titanium tetrachloride, and heated again at 110°C for 2 hours. After the reaction was complete, the solid was collected again by hot filtration and thoroughly washed with decane and hexane at 110°C until no free titanium compounds were detected in the solution.

The solid titanium catalyst component prepared as described above was stored as a hexane slurry, and a portion of this was dried to examine the catalyst composition. The solid titanium catalyst component contained 2.3% by mass of titanium, 61% by mass of chlorine, 19% by mass of magnesium, and 12.5% by mass of DIBP.

[Production of prepolymerization catalyst (b-1)]
100.0 g of solid titanium catalyst component (a-1), 19.2 ml of cyclohexylmethyldimethoxysilane, 65.6 mL of triethylaluminum, and 10 L of heptane were charged into a 20 L autoclave equipped with a stirrer, and 600 g of propylene was charged while maintaining the internal temperature at 15 to 20°C, and the reaction was carried out with stirring for 100 minutes. After completion of polymerization, the solid component was allowed to settle, and the supernatant was removed and washed with heptane twice. The obtained prepolymerized catalyst was resuspended in purified heptane and adjusted with heptane so that the solid catalyst component concentration was 1.0 g/L.

[Production of Propylene Homopolymer (D2-1)]
Propylene was continuously supplied at 43 kg/hour, hydrogen at 56 NL/hour, prepolymerization catalyst (b-1) at 0.77 g/hour, triethylaluminum at 2.3 mL/hour, and cyclohexylmethyldimethoxysilane at 4.3 mL/hour to a tubular polymerization reactor having an internal volume of 58 L, and polymerization was carried out in a liquid-filled state in the absence of a gas phase. The temperature of the tubular polymerization reactor was 70°C, and the pressure was 3.4 MPa/G.

The resulting slurry was sent to a 70 L vessel polymerization reactor equipped with a stirrer, where further polymerization was carried out. Propylene was supplied to the polymerization reactor at 45 kg/h, and hydrogen was supplied so that the hydrogen concentration in the gas phase was 2.9 mol%. Polymerization was carried out at a polymerization temperature of 70°C and a pressure of 3.1 MPa/G.

The resulting slurry was deactivated, and the propylene was evaporated to obtain a powdery propylene homopolymer. The resulting propylene homopolymer had an MFR of 9 g/10 min.

To 100 parts by mass of the resulting propylene homopolymer, 0.05 parts by mass of organic peroxide (trade name Perhexa 25B-40 (manufactured by NOF Corporation)) was added and thoroughly stirred. This mixture was melt-kneaded using a KTX 30mm twin-screw extruder manufactured by Kobe Steel, Ltd., at a cylinder temperature of 230°C and an extrusion rate of 25 kg/hr. The resulting propylene homopolymer (D2-1) had an MFR of 18 g/10 min and an Mw/Mn of 4.3.

Comparative Example 10
The propylene homopolymer (B2-1) obtained in Production Example 5 was used alone as the propylene polymer composition. The propylene homopolymer (B2-1) was extruded into a film using a film molding machine equipped with a T-die having a width of 600 mm at the tip of an extruder having a screw diameter of 75 mm and set at a temperature of 286°C, and the film was then cooled with a chill roll set at a temperature of 30°C to obtain an unstretched film having a thickness of 25 μm.

The physical properties of the obtained unstretched film were measured using the methods described above.

The results are shown in Table 4.

Example 5
An unstretched film was obtained in the same manner as in Comparative Example 10, except that a propylene polymer composition comprising 10 parts by mass of the propylene polymer (A-1) obtained in Production Example 1 and 90 parts by mass of the propylene homopolymer (B2-1) obtained in Production Example 5 was used instead of the propylene polymer composition used in Comparative Example 10.

The physical properties of the obtained unstretched film were measured using the methods described above.

The results are shown in Table 4.

Example 6
An unstretched film was obtained in the same manner as in Example 1, except that a propylene polymer composition comprising 30 parts by mass of a propylene polymer (A-1) and 70 parts by mass of a propylene homopolymer (B2-1) was used instead of the propylene polymer composition used in Example 5.

The physical properties of the obtained unstretched film were measured using the methods described above.

The results are shown in Table 4.

Comparative Example 11
An unstretched film was obtained in the same manner as in Comparative Example 10, except that the propylene homopolymer (B2-2) obtained in Production Example 6 was used instead of the propylene homopolymer (B2-1) used in Comparative Example 10.

The physical properties of the obtained unstretched film were measured using the methods described above.

The results are shown in Table 4.

Example 7
An unstretched film was obtained in the same manner as in Example 5, except that the propylene homopolymer (B2-2) was used instead of the propylene homopolymer (B2-1) used in Example 5.

The physical properties of the obtained unstretched film were measured using the methods described above.

The results are shown in Table 4.

Example 8
An unstretched film was obtained in the same manner as in Example 6, except that the propylene homopolymer (B2-2) was used instead of the propylene homopolymer (B2-1) used in Example 6.

The physical properties of the obtained unstretched film were measured using the methods described above.

The results are shown in Table 4.

Comparative Examples 12 to 14
An unstretched film was obtained in the same manner as in Comparative Example 10, except that the propylene polymer (A-1) and the propylene homopolymer (D-2) were used in the amounts shown in Table 3 as the propylene polymer composition.

The physical properties of the obtained unstretched film were measured using the methods described above.

The results are shown in Table 5.

[Comparative Examples 15 and 16]
The same procedure as in Comparative Example 10 was carried out except that the propylene polymer composition used contained the propylene polymer (A-1) and the propylene homopolymer (D-3) in the amounts shown in Table 5, to obtain an unstretched film.

The physical properties of the obtained unstretched film were measured using the methods described above.

The results are shown in Table 5.

Comparative Examples 17 to 19
The same procedure as in Comparative Example 10 was carried out except that the propylene polymer composition used contained the propylene polymer (A-1) and the propylene homopolymer (D2-1) in the amounts shown in Table 5, to obtain an unstretched film.

The physical properties of the obtained unstretched film were measured using the methods described above.

The results are shown in Table 5.

Claims (11)

The polymer contains 20 to 50 mass% of a propylene polymer (a1) having an intrinsic viscosity [η] of 10 to 12 dl/g as measured in tetralin at 135°C, and 50 to 80 mass% of a propylene polymer (a2) having an intrinsic viscosity [η] of 0.5 to 1.5 dl/g as measured in tetralin at 135°C (wherein the total amount of (a1) and (a2) is 100 mass%). and 60 to 99 mass% of a propylene homopolymer (B1) having a melt flow rate (MFR) of more than 10 g/10 min and not more than 40 g/10 min , as measured in accordance with JIS K 7210 at a temperature of 230°C and a load of 2.16 kg, and a ratio (Mw/Mn) of weight average molecular weight (Mw) to number average molecular weight (Mn ) of 4.5 to 6.0 (wherein the total amount of (A) and (B1) is taken as 100 mass%). The unstretched film according to claim 1, characterized in that the propylene polymer composition is a composition containing 1 to 20% by mass of a propylene polymer (A) and 80 to 99% by mass of a propylene homopolymer (B1). a propylene polymer (A) in the range of 20 to 50 mass% of a propylene polymer (a1) having an intrinsic viscosity [η] of 10 to 12 dl/g measured in tetralin solvent at 135°C, and a propylene polymer (A) in the range of 50 to 80 mass% of a propylene polymer (a2) having an intrinsic viscosity [η] of 0.5 to 1.5 dl/g measured in tetralin solvent at 135°C (wherein the total amount of (a1) and (a2) is 100 mass%);
A non-stretched film comprising a propylene polymer composition containing 60 to 80 mass% of a propylene homopolymer (B2) having a ratio (Mw/Mn) of weight average molecular weight (Mw) to number average molecular weight (Mn) of less than 4.0 and a melt flow rate (MFR) of 9 to 40 g/10 min measured in accordance with JIS K 7210 at a measurement temperature of 230°C under a load of 2.16 kg (wherein the total amount of (A) and (B2) is taken as 100 mass%). The non-oriented film according to claim 1 or 3, wherein the propylene polymer (A) is a polymer having a melt flow rate (MFR) measured in accordance with JIS K 7210 at a measurement temperature of 230°C and a load of 2.16 kg in the range of 0.01 to 5 g/10 min, and a melt tension measured at 230°C in the range of 5 to 30 g. 4. The non-stretched film according to claim 1, wherein the propylene-based polymer (A) is a polymer in which a proportion of an area of a high molecular weight region having a molecular weight of 1,500,000 or more to a total area enclosed by a molecular weight distribution curve measured by gel permeation chromatography (GPC) is 7% or more. 4. The non-stretched film according to claim 1, wherein the propylene polymer (A) is a polymer whose molecular weight distribution curve measured by GPC has two peaks, and the ratio (MH/ML) of the molecular weight of the higher molecular weight peak (MH) to the molecular weight of the lower molecular weight peak (ML) is 50 or more. 4. The non-stretched film according to claim 1, wherein the propylene polymer (A) is a polymer having a molecular weight (ML) of 100,000 or less at a peak on the low molecular weight side of a molecular weight distribution curve measured by GPC. the propylene polymer (a1) is a propylene homopolymer or a copolymer of propylene and an α-olefin having 2 to 8 carbon atoms (excluding propylene), in which the content of structural units derived from propylene is 90 mass% or more;
4. The non-oriented film according to claim 1, wherein the propylene polymer (a2) is a propylene homopolymer or a copolymer of propylene and an α-olefin having 2 to 8 carbon atoms (excluding propylene), wherein the content of structural units derived from propylene is 90% by mass or more. The non-stretched film according to claim 1 or 3 , wherein the non-stretched film has a tensile modulus in the machine direction of 2400 MPa or more and a haze measured in accordance with ASTM D-1003 (JIS K7105) of 10% or less. A laminate comprising the unstretched film according to claim 1 or 3 . a propylene polymer (A) containing 20 to 50% by mass of a propylene polymer (a1) having an intrinsic viscosity [η] of 10 to 12 dl/g measured in tetralin solvent at 135°C, and 1 to 40% by mass of a propylene polymer (a2) having an intrinsic viscosity [η] of 0.5 to 1.5 dl/g measured in tetralin solvent at 135°C (wherein the total amount of (a1) and (a2) is 100% by mass);
A laminate comprising an unstretched film made of a propylene polymer composition containing 60 to 99% by mass of a propylene homopolymer (B) selected from propylene homopolymers (B1) having a melt flow rate (MFR) of more than 10 g/10 min and not more than 40 g/10 min, as measured in accordance with JIS K 7210 at a temperature of 230°C and a load of 2.16 kg, and a ratio (Mw/Mn) of weight average molecular weight (Mw) to number average molecular weight (Mn) of 4.5 to 6.0, or propylene homopolymers (B2) having a ratio (Mw/Mn) of weight average molecular weight (Mw) to number average molecular weight (Mn) of less than 4.0 (wherein the total amount of (A) and (B) is taken as 100% by mass).