CN118451138A - Non-stretch films, sealing films and multi-layer sealing films - Google Patents

Abstract

The present invention provides an unstretched polypropylene film having a good balance of rigidity and low-temperature heat-sealing performance or an unstretched polypropylene film having excellent rigidity and capable of achieving heat sealing at low temperatures. The unstretched film of the present invention is formed by a propylene-based polymer composition, which contains, in a specific ratio, a specific propylene-based polymer (A); and a propylene-α-olefin copolymer (B) having an MFR of 0.1 to 30 g/10 minutes, an intrinsic viscosity [η] measured at 135° C. in a tetralin solvent of higher than 1.5 dl/g and less than 5.0 dl/g, and containing a specific amount of structural units derived from α-olefins (excluding propylene).

Description

Non-stretch films, sealing films and multi-layer sealing films

Technical Field

The invention relates to a non-stretched film, a sealing film and a multi-layer sealing film.

Background technique

Propylene polymers are widely used as materials for various molded bodies (see, for example, Patent Documents 1 to 4), and the properties required vary depending on the molding method and application. For example, films formed from propylene polymers are widely used as packaging films for food and general merchandise, taking advantage of their excellent mechanical properties such as rigidity and optical properties such as gloss. Unstretched polypropylene films (see, for example, Patent Documents 5 to 7) are known to have an excellent balance between rigidity and heat resistance. In addition, Patent Document 8 discloses an unstretched polypropylene film having particularly excellent rigidity using a specific propylene polymer.

Prior art literature

Patent Literature

Patent Document 1: International Publication No. 1999/007752

Patent Document 2: International Publication No. 2005/097842

Patent Document 3: Japanese Patent Application Publication No. 2001-302858

Patent Document 4: Japanese Patent Application Publication No. 2006-045446

Patent Document 5: Japanese Patent Application Publication No. 2002-265712

Patent Document 6: Japanese Patent Application Publication No. 2005-320359

Patent Document 7: Japanese Patent Application Publication No. 2011-236357

Patent Document 8: International Publication No. 2021/025142

Summary of the invention

Technical problem to be solved by the invention

However, when the unstretched polypropylene film described in Patent Document 8 is used as a sealing film, the sealing performance is low (the sealing temperature is high).

Therefore, a first object of the present invention (hereinafter referred to as “first object”) is to provide an unstretched polypropylene film having a good balance between rigidity and low-temperature heat-sealing performance.

A second object of the present invention (hereinafter referred to as “second object”) is to provide an unstretched polypropylene film which has excellent rigidity and can be heat-sealed at low temperatures.

Technical solutions for solving technical problems

The inventors of the present invention have conducted intensive studies and have found that an unstretched film made of a propylene polymer composition described below can solve the first problem, thereby completing the first aspect of the present invention. The first aspect of the present invention relates to, for example, the following [1].

[1] An unstretched film comprising a propylene polymer composition (X1), wherein the propylene polymer composition (X1) comprises a propylene polymer (A) and a propylene-α-olefin copolymer (B1),

The propylene polymer (A) comprises: 20 to 50% by weight of a propylene polymer (a1) having an intrinsic viscosity [η] in the range of 10 to 12 dl/g as measured at 135° C. in a tetralin solvent; and 50 to 80% by weight of a propylene polymer (a2) having an intrinsic viscosity [η] in the range of 0.5 to 1.5 dl/g as measured at 135° C. in a tetralin solvent, wherein the total amount of the propylene polymer (a1) and the propylene polymer (a2) is 100% by weight.

The propylene-α-olefin copolymer (B1) has a melt flow rate (230° C., 2.16 kg load) of 0.1 to 30 g/10 min, an intrinsic viscosity [η] measured at 135° C. in a tetralin solvent of higher than 1.5 dl/g and not more than 5.0 dl/g, and contains 5.5 mol% or more of structural units derived from α-olefins (excluding propylene),

The content of the propylene polymer (A) is 1 to 10 parts by mass and the content of the propylene-α-olefin copolymer (B1) is 90 to 99 parts by mass based on 100 parts by mass of the total of the propylene polymer (A) and the propylene-α-olefin copolymer (B1).

The inventors of the present invention have conducted further intensive studies and have found that an unstretched film made of a propylene polymer composition described below can solve the second problem, thereby completing the second aspect of the present invention. The second aspect of the present invention relates to, for example, the following [2].

[2] An unstretched film comprising a propylene polymer composition (X2), wherein the propylene polymer composition (X2) comprises a propylene polymer (A) and a propylene-α-olefin copolymer (B2),

The propylene polymer (A) comprises: 20 to 50% by weight of a propylene polymer (a1) having an intrinsic viscosity [η] in the range of 10 to 12 dl/g as measured at 135° C. in a tetralin solvent; and 50 to 80% by weight of a propylene polymer (a2) having an intrinsic viscosity [η] in the range of 0.5 to 1.5 dl/g as measured at 135° C. in a tetralin solvent, wherein the total amount of the propylene polymer (a1) and the propylene polymer (a2) is 100% by weight.

The propylene-α-olefin copolymer (B2) has a melt flow rate (230° C., 2.16 kg load) of 0.1 to 30 g/10 min, an intrinsic viscosity [η] measured at 135° C. in a tetralin solvent of higher than 1.5 dl/g and lower than 5.0 dl/g, and contains 1 mol % or more and less than 5.5 mol % of structural units derived from α-olefins (excluding propylene),

The content of the propylene polymer (A) is 1 to 18 parts by mass and the content of the propylene-α-olefin copolymer (B2) is 82 to 99 parts by mass based on 100 parts by mass of the total of the propylene polymer (A) and the propylene-α-olefin copolymer (B2).

The first and second aspects of the present invention also relate to the following [3] to [6].

[3] The unstretched film of [1] or [2] above, wherein the melt flow rate (MFR) of the propylene polymer (A) measured at 230°C and a load of 2.16 kg is 0.01 to 5 g/10 min.

[4] An unstretched film as described in any one of [1] to [3] above, wherein the proportion of the area of the high molecular weight region with a molecular weight of 1.5 million or more in the total area of the region enclosed by the molecular weight distribution curve of the propylene-based polymer (A) measured by gel permeation chromatography (GPC) is 7% or more.

[5] An unstretched film as described in any one of [1] to [4] above, wherein the molecular weight distribution curve of the propylene-based polymer (A) measured by GPC has two peaks, and the ratio of the peak molecular weight MH on the high molecular weight side to the peak molecular weight ML on the low molecular weight side (MH/ML) is greater than 50.

[6] The unstretched film according to any one of [1] to [5] above, wherein the axial orientation degree of the PP (110) plane determined by wide-angle X-ray diffraction measurement is 0.85 or more.

The first aspect of the present invention also relates to the following [7].

[7] A sealing film, wherein the sealing film is a laminate having a sealing film body and a surface layer in this order, and the surface layer is the unstretched film described in any one of [1] or [3] to [6] (wherein [1] is directly or indirectly cited).

The second aspect of the present invention also relates to the following [8].

[8] A multilayer sealing film, wherein the multilayer sealing film is a laminate having an outer layer, an intermediate layer and a sealing layer in sequence, and the intermediate layer is the unstretched film described in any one of [2] or [3] to [6] (wherein [2] is directly or indirectly cited).

Effects of the Invention

The unstretched film of the first aspect of the present invention has well-balanced and excellent rigidity and low-temperature heat-sealing performance (that is, a low sealing start temperature described later).

The unstretched film according to the second aspect of the present invention is excellent in rigidity and also excellent in sealing performance (that is, the sealing start temperature described below is low).

Detailed ways

Hereinafter, the mode for carrying out the present invention will be described.

[No stretch film]

The unstretched film according to the first aspect of the present invention is formed from a propylene polymer composition (X1) containing a propylene polymer (A) and a propylene-α-olefin copolymer (B1) as described below.

The unstretched film according to the second aspect of the present invention is formed from a propylene polymer composition (X2) containing a propylene polymer (A) and a propylene-α-olefin copolymer (B2) as described below.

Hereinafter, the propylene-α-olefin copolymer (B1) and the propylene-α-olefin copolymer (B2) are also collectively referred to as “propylene-α-olefin copolymer (B)” unless there is any particular need to distinguish them.

In addition, when there is no particular need to distinguish, the propylene polymer composition (X1) and the propylene polymer composition (X2) are also collectively referred to as "propylene polymer composition (X)".

In addition, the details of the measurement conditions of each requirement are described in the Examples.

[Propylene polymer (A)]

The propylene polymer (A) contains: 20 to 50% by mass of a propylene polymer (a1) having an intrinsic viscosity [η] in the range of 10 to 12 dl/g as measured at 135°C in a tetralin solvent; and 50 to 80% by mass of a propylene polymer (a2) having an intrinsic viscosity [η] in the range of 0.5 to 1.5 dl/g as measured at 135°C in a tetralin solvent, wherein the total amount of the propylene polymer (a1) and the propylene polymer (a2) is 100% by mass.

Hereinafter, the intrinsic viscosity [η] measured in a tetralin solvent at 135°C is also referred to as “intrinsic viscosity [η].” The mass fractions of the propylene polymer (a1) and the propylene polymer (a2) are based on the total amount of (a1) and (a2).

<Propylene-based polymer (a1)>

The intrinsic viscosity [η] of the propylene polymer (a1) is in the range of 10 to 12 dl/g, preferably in the range of 10.5 to 11.5 dl/g. In addition, the mass fraction of the propylene polymer (a1) in the propylene polymer (A) is in the range of 20 to 50 mass %, preferably in the range of 20 to 45 mass %, more preferably in the range of 20 to 40 mass %, and further preferably in the range of 22 to 40 mass %.

Examples of the propylene-based polymer (a1) include homopolymers of propylene 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. Ethylene is preferred among these α-olefins. One or more α-olefins may be used.

In the copolymer of propylene and an α-olefin having 2 to 8 carbon atoms, the content of the structural unit 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 the structural unit 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 above content can be measured by ¹³ C-NMR.

From the viewpoint of being able to suppress the number of fish eyes (FE) in a film obtained from the polymer composition, the intrinsic viscosity [η] of the propylene polymer (a1) is preferably within a range of 10 to 12 dl/g.

On the other hand, when the intrinsic viscosity [η] of the propylene polymer (a1) exceeds 12 dl/g, there is a tendency that the film formability is poor and the film surface appearance deteriorates. In addition, when the intrinsic viscosity [η] of the propylene polymer (a1) is less than 10 dl/g, there is a tendency that the rigidity, heat resistance and gas barrier properties of the obtained film are insufficient.

When the mass fraction of the propylene-based polymer (a1) is less than 20 mass %, the melt tension of the resulting polymer composition tends to be insufficient, and the rigidity, heat resistance and gas barrier properties of the resulting film tend to be insufficient; when it exceeds 50 mass %, there is a tendency to cause poor appearance during film molding.

The propylene-based polymer (a1) may be used alone or in combination of two or more.

<Propylene-based polymer (a2)>

The intrinsic viscosity [η] of the propylene polymer (a2) is in the range of 0.5 to 1.5 dl/g, preferably in the range of 0.6 to 1.5 dl/g, and more preferably in the range of 0.8 to 1.5 dl/g. In addition, the mass fraction of the propylene polymer (a2) in the propylene polymer (A) is in the range of 50 to 80 mass %, preferably in the range of 55 to 80 mass %, more preferably in the range of 60 to 80 mass %, and further preferably in the range of 60 to 78 mass %.

Examples of the propylene-based polymer (a2) include homopolymers of propylene 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. Ethylene is preferred among these α-olefins. One or more α-olefins may be used.

In the copolymer of propylene and an α-olefin having 2 to 8 carbon atoms, the content of the structural unit 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 the structural unit 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 above content can be measured by ¹³ C-NMR.

When the intrinsic viscosity [η] of the propylene polymer (a2) is less than 0.5 dl/g, the melt tension of the obtained polymer composition tends to be insufficient and the fisheye of the obtained film tends to be poor. When the intrinsic viscosity [η] exceeds 1.5 dl/g, the viscosity tends to be high and the film formability tends to be poor.

When the mass fraction of the propylene-based polymer (a2) is less than 50 mass %, there is a tendency to cause poor appearance during film molding. When it exceeds 80 mass %, there is a tendency for the melt tension of the obtained polymer composition to be insufficient and the rigidity, heat resistance and gas barrier properties of the obtained film to be insufficient.

The propylene-based polymer (a2) may be used alone or in combination of two or more.

＜Additives＞

The propylene polymer (A) may be mixed with additives such as antioxidants, neutralizers, 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 may be appropriately adjusted.

<Physical Properties of Propylene Polymer (A)>

The melt flow rate (MFR) of the propylene polymer (A) measured at 230°C and a load of 2.16 kg is preferably in the range of 0.01 to 5 g/10 min, more preferably in the range of 0.05 to 4 g/10 min, and further preferably in the range of 0.1 to 3 g/10 min. When the MFR of the propylene polymer (A) is within the above range, film formability is excellent.

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

The melt tension (MT) can be measured using the following apparatus and conditions.

Apparatus: CAPILOGRAPH 1C (trade name) manufactured by Toyo Seiki Co., Ltd.;

Temperature: 230℃;

Orifice: L = 8mm, D = 2.095mm;

Extrusion speed: 15mm/min;

Pulling speed: 15m/min.

The proportion of the area of the high molecular weight region with a molecular weight of 1.5 million or more in the total area of the region enclosed by the molecular weight distribution curve of the propylene polymer (A) measured by gel permeation chromatography (GPC) (equivalent to the mass proportion of the high molecular weight component with a molecular weight of 1.5 million or more) is preferably 7% or more, more preferably 10% or more, and further preferably 12% or more. The upper limit of the above-mentioned area ratio is, for example, 30%, preferably 25%. The area ratio of the above-mentioned high molecular weight region accounts for more than a specific ratio, which means that the propylene polymer (A) contains a high molecular weight component with a molecular weight of 1.5 million or more. At least a part of the high molecular weight component is a high molecular weight component with an intrinsic viscosity [η] of 10 to 12 dl/g. Therefore, when the proportion of the above-mentioned high molecular weight component is within the above range, the melt tension of the polymer composition becomes more excellent.

The propylene polymer (A) preferably has two peaks in the molecular weight distribution curve measured by GPC. Among them, the ratio (MH/ML) of the peak molecular weight MH on the high molecular weight side to the peak molecular weight ML on the low molecular weight side is preferably 50 or more, more preferably 70 or more, and further preferably 90 or more. The upper limit of the ratio (MH/ML) is, for example, 500, preferably 300. The molecular weight distribution curve has two peaks and MH/ML is above a specific value, indicating that the content of the high molecular weight component in the polymer is high and its intrinsic viscosity [η] is also high. Therefore, this type of propylene polymer (A) contributes to the improvement of melt tension, rigidity when forming a film, and improvement of heat resistance.

From the viewpoint of viscosity and film formability, the peak molecular weight ML on the low molecular weight side of the molecular weight distribution curve of the propylene polymer (A) measured by GPC is preferably 100,000 or less, more preferably 80,000 or less, and even more preferably 50,000 or less.

<Method for producing propylene polymer (A)>

As a method for producing the propylene-based polymer (A), various known production methods can be mentioned, and for example, the method described in paragraphs [0038] to [0075] of International Publication No. 2021/025142 can be mentioned.

[Propylene-α-olefin copolymer (B)]

The propylene-α-olefin copolymer (B1) has a melt flow rate (MFR) of 0.1 to 30 g/10 min as measured at 230° C. and a load of 2.16 kg, an intrinsic viscosity [η] as measured at 135° C. in a tetralin solvent of higher than 1.5 dl/g and lower than 5.0 dl/g, and contains 5.5 mol % or more of structural units derived from α-olefins (excluding propylene).

The propylene-α-olefin copolymer (B2) has a melt flow rate (MFR) of 0.1 to 30 g/10 min as measured at 230° C. and a load of 2.16 kg, an intrinsic viscosity [η] as measured at 135° C. in a tetralin solvent of higher than 1.5 dl/g and lower than 5.0 dl/g, and contains at least 1 mol % and less than 5.5 mol % of structural units derived from α-olefins (excluding propylene).

The intrinsic viscosity [η] of the propylene-α-olefin copolymer (B) is higher than 1.5 dl/g and lower than 5.0 dl/g, preferably higher than 1.5 dl/g and lower than 4.5 dl/g, more preferably higher than 1.5 dl/g and lower than 4.0 dl/g, and further preferably higher than 1.5 dl/g and lower than 2.5 dl/g. When the propylene-α-olefin copolymer (B) having an intrinsic viscosity [η] within the above range is used, the productivity during film molding is good, and the impact resistance of the obtained film is good.

The melt flow rate (MFR) of the propylene-α-olefin copolymer (B) measured at 230°C and a load of 2.16 kg is 0.1 to 30 g/10 min, preferably 0.3 to 10 g/10 min, and more preferably 0.5 to 10 g/10 min. When the propylene-α-olefin copolymer (B) having an MFR within the above range is used, the productivity during film molding is good, and the impact resistance of the obtained film is good.

The melting point (Tm) of the propylene-α-olefin copolymer (B1), specifically, the melting point (Tm) measured using a differential scanning calorimeter (DSC) under the conditions used in the examples described below, is preferably 120 to 170° C., more preferably 125 to 170° C., and even more preferably 125 to 135° C. From the viewpoint of moldability and heat resistance, the melting point (Tm) is preferably within the above range.

The melting point (Tm) of the propylene-α-olefin copolymer (B2), specifically, the melting point (Tm) measured using a differential scanning calorimeter (DSC) under the conditions used in the examples described below, is preferably 120 to 170° C., more preferably 125 to 170° C., further preferably 130 to 170° C., and particularly preferably 130 to 155° C. From the viewpoint of moldability and heat resistance, the melting point (Tm) is preferably within the above range.

The molecular weight distribution (Mw/Mn) of the propylene-α-olefin copolymer (B) measured by gel permeation chromatography (GPC) is preferably 4.0 or more, more preferably 4.0 to 6.5, and even more preferably 4.0 to 6.0, wherein Mn is the number average molecular weight and Mw is the weight average molecular weight.

Examples of the propylene-α-olefin copolymer (B) include propylene-α-olefin random copolymers, block-type propylene copolymers (a mixture of a propylene homopolymer or a propylene-α-olefin random copolymer and an amorphous or low-crystalline propylene-α-olefin random copolymer), and random block polypropylene.

Examples of the α-olefins include α-olefins having 2 to 12 carbon atoms, such as ethylene, 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, 1-decene, 4-methyl-1-pentene, and 3-methyl-1-pentene. Preferred α-olefins include ethylene, 1-butene, 1-hexene, 1-octene, and 4-methyl-1-pentene. One or more α-olefins may be used.

In the propylene-α-olefin copolymer (B1), the content of the structural units derived from α-olefin (excluding propylene) is 5.5 mol% or more, preferably 5.5 to 9.0 mol%, more preferably 5.5 to 7.0 mol%, when the total content of the structural units derived from propylene and the structural units derived from α-olefin is 100 mol%.

In the propylene-α-olefin copolymer (B2), the content ratio of the structural unit derived from α-olefin (excluding propylene) is 1 mol% or more and less than 5.5 mol%, preferably 1.5 to 4.5 mol%, more preferably 2.0 to 4.0 mol% in the case of the propylene-α-olefin copolymer (B2).

The above content ratio can be measured by ¹³ C-NMR.

The propylene-α-olefin copolymer (B) can be produced by copolymerizing propylene with other α-olefins using a catalyst, and a commercially available polypropylene resin can also be used. As the catalyst, for example, a catalyst composed of a solid catalyst component having magnesium, titanium and halogen as essential components, an organic metal compound catalyst component such as an organic aluminum compound, and an electron-donating compound catalyst component such as an organic silicon compound as described in paragraphs [0050] to [0075] of International Publication No. 2021/025142; and a metallocene catalyst using a metallocene compound as one of the components of the catalyst.

The propylene-based polymer (A) and the propylene-α-olefin copolymer (B) may each contain at least one structural unit of a monomer (propylene) derived from biomass. The same monomers constituting the polymer may be only monomers derived from biomass, only monomers derived from fossil fuels, or both monomers derived from biomass and monomers derived from fossil fuels. Monomers derived from biomass refer to monomers formed from all renewable natural raw materials and their residues, including fungi, yeast, algae and bacteria, of plant or animal origin, as carbon, containing ¹⁴ C isotopes at a ratio of about 1×10 ^-12 , and having a biomass carbon concentration (pMC) of about 100 (pMC) measured according to ASTM D6866. Monomers derived from biomass (propylene) can be obtained, for example, by conventionally known methods.

From the viewpoint of reducing environmental load, it is preferred that the propylene polymer (A) or the propylene-α-olefin copolymer (B) contains a structural unit derived from a monomer derived from biomass. When the polymer production conditions such as the polymerization catalyst and the polymerization temperature are the same, even if the raw material olefin is a propylene polymer or a propylene-α-olefin copolymer containing an olefin derived from biomass, the molecular structure is the same as that of a propylene polymer or a propylene-α-olefin copolymer composed of a monomer derived from fossil fuels, except for containing ¹⁴ C ^isotopes at a ratio of about 1×10-12. Therefore, their performance does not change.

The propylene polymer (A) and the propylene-α-olefin copolymer (B) may also contain at least one structural unit of a monomer (propylene) derived from chemical recycling. The monomers of the same kind constituting the polymer may be only monomers derived from chemical recycling, or may include monomers derived from chemical recycling, monomers derived from fossil fuels, and/or monomers derived from biomass. The monomer (propylene) derived from chemical recycling can be obtained, for example, by a conventionally known method.

From the viewpoint of reducing environmental load (mainly reducing waste), it is preferred that the propylene polymer (A) and the propylene-α-olefin copolymer (B) contain structural units of monomers derived from chemical recycling sources. Even if the raw material monomers contain monomers derived from chemical recycling sources, since the monomers derived from chemical recycling sources are monomers that return polymers such as waste plastics to monomer units such as ethylene by depolymerization, thermal cracking, etc., and monomers produced using these monomers as raw materials, as long as the polymer production conditions such as polymerization catalysts, polymerization processes, and polymerization temperatures are the same, the molecular structure is also the same as that of propylene polymers or propylene-α-olefin copolymers composed of monomers derived from fossil fuels. Therefore, their performance will not change.

[Other ingredients (additives)]

The propylene polymer composition (X) may contain additives such as weather 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 absorbents, adhesives, flame retardants, and mold release agents, within the scope of not impairing the purpose of the present invention. The additives may be used alone or in combination of two or more.

[Preparation and physical properties of propylene polymer composition (X)]

The propylene polymer composition (X) can be produced by any known method, for example, a method in which the propylene polymer (A) and the propylene-α-olefin copolymer (B) and other components as required are mixed using a Henschel mixer, a V-blender, a ribbon blender, a drum blender, etc.; or a method in which after the above mixing, the mixture is melt-kneaded using a single-screw extruder, a twin-screw extruder, a kneader, a Banbury mixer, a roll, etc., and then pelletized or pulverized.

In the propylene polymer composition (X1), the content of the propylene polymer (A) is 1 to 10 parts by mass, preferably 3 to 10 parts by mass, and more preferably 4 to 10 parts by mass, and the content of the propylene-α-olefin copolymer (B1) is 90 to 99 parts by mass, preferably 90 to 97 parts by mass, and more preferably 90 to 96 parts by mass, relative to 100 parts by mass in total of the propylene polymer (A) and the propylene-α-olefin copolymer (B1).

The unstretched film of the present invention having the contents of the propylene polymer (A) and the propylene-α-olefin copolymer (B) within the above ranges has well-balanced and excellent rigidity and heat-sealing properties, and also has an excellent appearance after heat sealing.

On the other hand, when the content of the propylene-α-olefin copolymer (B1) is less than 90 parts by mass, the sealing performance of the film tends to be poor, that is, the heat sealing temperature tends to be high, and the appearance of the film after heat sealing sometimes tends to be poor. When the content of the propylene-α-olefin copolymer (B1) is more than 99 parts by mass, the rigidity of the film tends to be poor, that is, the tensile elastic modulus tends to be low.

In the above-mentioned propylene polymer composition (X2), the content of the propylene polymer (A) is 1 to 18 parts by mass, preferably 3 to 10 parts by mass, and more preferably 4 to 10 parts by mass, and the content of the propylene-α-olefin copolymer (B2) is 82 to 99 parts by mass, preferably 90 to 97 parts by mass, and more preferably 90 to 96 parts by mass, relative to 100 parts by mass in total of the propylene polymer (A) and the propylene-α-olefin copolymer (B2).

When the content of the propylene-α-olefin copolymer (B2) is less than 82 parts by mass, the sealing performance of the film tends to be poor, that is, the heat sealing temperature tends to be high. When the content of the propylene-α-olefin copolymer (B2) is more than 99 parts by mass, the rigidity of the film tends to be poor, that is, the tensile elastic modulus tends to be low.

In the present invention, from the viewpoints of rigidity and heat resistance and reduction of fisheyes, it is preferred to prepare the propylene polymer composition (X) by mixing a propylene polymer (A) obtained by intermittent multistage polymerization and comprising a propylene polymer (a1) and a propylene polymer (a2) with a propylene-α-olefin copolymer (B).

The molecular weight distribution (Mw/Mn) of the propylene polymer composition (X) measured by gel permeation chromatography (GPC) is preferably 5.0 or more, more preferably 5.5 or more, and even more preferably 6.0 or more. The upper limit is not particularly limited, and is 25, for example.

In the present invention, since the propylene polymer (a2) and the propylene-α-olefin copolymer (B) and the propylene polymer (a1) having a molecular weight higher than these two are used, the molecular weight distribution of the propylene polymer composition (X) becomes large. Therefore, it is inferred that when the film of the propylene polymer composition (X) is formed, the degree of orientation along the MD direction of the forming increases, and the propylene polymer is highly crystallized by the orientation, so it is considered that a film excellent in rigidity, heat resistance and gas barrier properties can be obtained.

The propylene polymer composition (X) has a melt flow rate (MFR) measured at 230°C and a load of 2.16 kg of usually 1 to 20 g/10 min, preferably 2 to 15 g/10 min, more preferably 3 to 10 g/10 min.

[No stretch film]

The non-stretched film of the present invention is formed from the above-mentioned propylene polymer composition (X). The non-stretched film of the present invention exhibits higher rigidity, heat resistance and gas barrier properties than the existing non-stretched polypropylene film. The above-mentioned non-stretched film can be used as a packaging material for food, beverages, industrial parts, general merchandise, 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. The unstretched film of the present invention has excellent rigidity and can be easily formed into a thin film.

In addition, the axial orientation degree of the PP (110) plane of the unstretched film of the present invention determined by wide-angle X-ray diffraction measurement (the details of the measurement method are described later) is preferably 0.85 or more, more preferably 0.88 or more. When the above-mentioned axial orientation degree is within this range, the molecules are fully oriented and the tensile elastic modulus of the film is improved. The upper limit of the above-mentioned axial orientation degree can be, for example, 0.91. The value of the above-mentioned axial orientation degree can be increased or decreased by, for example, changing the film forming speed, changing the intrinsic viscosity [η] of the propylene-based polymer (a1).

Examples of the method for producing the film include extrusion molding methods such as a T-die method and an inflation method, compression molding methods, calendar molding methods, and casting methods.

Film forming can be performed, for example, as follows. The above-mentioned components constituting the above-mentioned propylene-based polymer composition (X) can be directly put into a hopper of a film-forming machine, etc., or the above-mentioned components can be pre-mixed using a ribbon blender, a Banbury mixer, a Henschel mixer, a high-speed mixer, etc., or further melt-kneaded using a single-screw extruder or a twin-screw extruder, a roll or other kneading machine to obtain the propylene-based polymer composition (X), and then film forming is performed.

If a specific example of manufacturing a film using the T-die method is described, the above-mentioned components are added to an extruder, usually melt-kneaded 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 pulled by a puller such as a traction roller to obtain a film.

As the cooling method of the molten film, there can be cited, for example, a cooling method using roller and air cooling using an air knife method or an air chamber method; an extrusion cooling method using a polishing roller method, an oscillating roller method, a belt casting method, etc.; and a contact cooling method using a refrigerant using a water cooling method.

The obtained unstretched film may be subjected to a film treatment method generally used for film forming, for example, a corona discharge treatment or a liquid agent coating treatment.

[Sealing films and multi-layer sealing films]

The sealing film of the present invention has the non-stretched film of the first aspect of the present invention as a surface layer.

The sealing film of the present invention is formed of a laminate having a sealing film main body and a surface layer in this order. Examples of the method for producing the sealing film include a coextrusion method and an extrusion coating method.

The sealing film main body and the surface layer may be a single layer or multiple layers respectively.

The multi-layer sealing film of the present invention has the non-stretched film of the second aspect of the present invention as an intermediate layer.

The multilayer sealing film of the present invention is formed of a laminate having an outer layer, an intermediate layer and a sealing layer in this order. Examples of the method for producing the multilayer sealing film include a coextrusion method and an extrusion coating method.

The outer layer, the middle layer and the sealing layer can be a single layer or multiple layers respectively.

Examples of the material of the sealant layer include materials used in conventional sealants, such as vinyl resins.

Examples of the sealing film main body and the outer layer include a base material layer.

The substrate layer is formed of a material having high rigidity and strength. Examples of the above-mentioned material include: a film (which may be a stretched film) containing at least one thermoplastic resin selected from polyamide resins such as nylon 11 and nylon 12, polyester resins such as polyethylene terephthalate and polybutylene terephthalate, polyolefin resins such as polyethylene resin and polypropylene resin, polyvinylidene chloride resin, ethylene-vinyl acetate copolymer saponification product, polycarbonate resin, polystyrene resin, and acrylic resin; metal foil; metal vapor-deposited film; ceramic vapor-deposited film such as inorganic oxide vapor-deposited film; paper; non-woven fabric; and at least one of the laminates of the above-mentioned materials.

The thickness of the substrate layer is usually about 5 to 50 μm.

Examples of the sealing film body and the outer layer include, in addition to the substrate layer, a barrier layer for gases such as water vapor and oxygen, a sound absorbing layer, a light shielding layer, an adhesive layer, a bonding layer, a coloring layer, a conductive layer, and a layer containing a recycled resin (these layers other than the substrate layer are also collectively referred to as "other layers").

In the sealant film, as the raw material for forming the other layers, examples of the materials of these layers include olefin polymer compositions other than the propylene polymer composition (X1), gas barrier resin compositions, and adhesive resin compositions.

In the multilayer sealant film, as raw materials for forming the other layers, examples of the materials for these layers include olefin polymer compositions other than the propylene polymer composition (X2), gas barrier resin compositions, and adhesive resin compositions.

Since the sealing film of the present invention has the first non-stretched film of the present invention as a surface layer, it can achieve heat sealing at low temperatures, specifically, can achieve sealing at a sealing start temperature lower than 140°C, preferably 135°C or lower, as described below, and has a high tensile elastic modulus. In addition, the appearance after heat sealing is also excellent.

The multilayer sealing film of the present invention has the non-stretched film of the second aspect of the present invention as an intermediate layer. Therefore, the intermediate layer contributes to heat sealing at a lower temperature than when a propylene homopolymer is used for the intermediate layer. In addition, the multilayer sealing film of the present invention has a higher tensile elastic modulus than when a conventional propylene-α-olefin copolymer is used.

The non-stretched film, sealing film and multi-layer sealing film of the present invention can be used as packaging films in a wide range of packaging fields, such as various food packaging fields such as fresh foods such as vegetables and fish, snacks, dried foods such as noodles, soups, pickles and other water-containing foods; medical products in various forms such as tablets, powders, liquids, etc., medical-related product packaging fields used for medical peripheral materials; various electrical equipment packaging fields such as cassette tapes and electrical components.

Example

The present invention will be described in more detail below based on examples, but the present invention is not limited to these examples. It should be noted that the various properties of the polymer, polymer composition, and unstretched film obtained in each example were measured and evaluated as follows.

(1) Mass fraction

In Production Example 1, the mass fractions of the propylene-based polymer obtained in the first stage (corresponding to the propylene-based polymer (a1)) and the propylene-based polymer obtained in the second stage (corresponding to the propylene-based polymer (a2)) were determined from the amount of heat dissipated from the reaction heat generated during polymerization.

(2) Intrinsic viscosity [η]

The intrinsic viscosity [η] (dl/g) is measured at 135° C. in a tetralin solvent. The intrinsic viscosity [η] ₂ of the propylene polymer obtained in the second stage (corresponding to the propylene polymer (a2)) is a value 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 propylene-based polymer obtained in the first stage (%)

W ₂ : Mass fraction of propylene-based polymer obtained in the second stage (%)

(3) Comonomer content

The ¹ H-NMR spectrum was measured using o-dichlorobenzene-d4 as the measuring solvent at a measuring temperature of 120° C., a spectrum width of 20 ppm, a pulse repetition time of 7.0 seconds, and a pulse width of 6.15 μsec (450 pulses) (400 MHz, JEOL ECX400P), and the comonomer content was calculated.

(4) Melt flow rate (MFR)

The melt flow rate (MFR) (g/10 minutes) was measured in accordance with JIS-K7210 under the conditions of a measurement temperature of 230° C. and a load of 2.16 kgf (21.2 N).

(5) Ratio of high molecular weight region with molecular weight of 1.5 million or more, ML, MH/ML

The ratio of the high molecular weight region with a molecular weight of 1.5 million or more is the ratio of the area of the high molecular weight region with a molecular weight of 1.5 million or more to the total area of the region enclosed by the molecular weight distribution curve (specifically, the molecular weight distribution curve and the horizontal axis) measured by gel permeation chromatography (GPC) using the following apparatus and conditions. Here, the horizontal axis is the molecular weight (logarithmic value) and the vertical axis is 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 above molecular weight distribution curve are obtained, and MH/ML is calculated.

GPC measurement equipment

Gel permeation chromatograph: HLC-8321GPC/HT (manufactured by Tosoh Corporation) analysis device

Data processing software: Empower 3 (manufactured by Waters Corporation)

Determination conditions:

Column: TSKgel GMH6-HT×2+TSKgel GMH6-HTL×2

(All 7.5mm I.D.×30cm, manufactured by Tosoh Corporation)

Column temperature: 140°C

Mobile phase: o-dichlorobenzene (containing 0.025% BHT)

Detector: Differential Refractometer

Flow rate: 1.0mL/min

Sample concentration: 0.1% (w/v)

Injection volume: 0.4mL

Sampling time interval: 1s

Column calibration: Monodisperse polystyrene (manufactured by Tosoh Corporation)

Molecular weight conversion: PP conversion/universal calibration method (viscosity conversion coefficient of PS (polystyrene) K _PS = 0.000138 dl/g, α _PS = 0.700, viscosity conversion coefficient of PP (polypropylene) K _PP = 0.000242 dl/g, α _PP = 0.707)

(6) Melting point

According to JIS-K7121, a differential scanning calorimeter (DSC, manufactured by PerkinElmer (Diamond DSC)) was used to measure under the following measurement conditions to obtain the crystalline melting point. It should be noted that the apex of the endothermic peak in the fourth step when the measurement is performed under the following measurement conditions is defined as the crystalline melting point (Tm). When there are multiple endothermic peaks, the apex of the endothermic peak with the largest peak height is defined as the crystalline melting point (Tm).

(Measurement conditions)

Measurement environment: Nitrogen atmosphere

Sample size: 5 mg

Sample shape: pressed film (molded at 230℃, thickness 400μm)

Sample pan: Aluminum sample pan with flat bottom

Step 1: Raise the temperature from 30°C to 200°C at 320°C/min and maintain for 10 minutes.

Step 2: Cool down to 30°C at 20°C/min.

Step 3: Keep at 30℃ for 10 minutes.

Step 4: Raise the temperature to 200°C at 20°C/min.

(7) Membrane elastic modulus

The tensile modulus (MPa) was measured according to the method of JIS K7161. The measurement was performed in the extrusion direction (MD) of molding at 23° C. It is considered that the higher the tensile modulus, the higher the rigidity.

(8) Sealing start temperature

Using a heat seal tester manufactured by Toyo Seiki, a test piece with a width of 100 mm and a length of 150 mm was cut from the film manufactured in the examples, etc., folded in half, and heat-sealed at a predetermined heater temperature, a pressure of 0.2 MPa, and a sealing time of 1.0 second. The sealed test piece was then cut into a test piece with a width of 15 mm, and the peel strength (N/15 mm) was measured at a test speed of 300 mm/min using TENSILON RT1225 manufactured by ORIENTEC CORPORATION. The heater temperature was changed in increments of 1°C and the measurement was repeated to determine the minimum value of the heater temperature for achieving a peel strength of 2.94 N/15 mm or more (hereinafter referred to as the "sealing start temperature").

(9) Axis orientation

A wide-angle X-ray diffraction device (RINT2550 manufactured by Rigaku Corporation, accessory: rotating sample stage, X-ray source: CuKα, output: 40 kV, 370 mA, detector: scintillation counter) was used to stack the samples with the MD direction as the reference axis and fix them on the sample holder to measure the azimuthal distribution intensity of the crystal plane peak (110). In the obtained azimuthal distribution curve (X-ray interferogram), the orientation degree F (axial orientation degree) was calculated from the following formula based on the crystallinity and the half-value width (α) of the peak and evaluated.

Orientation degree (F) = (180° - α) / 180°

(α is the half-value width of the peak derived from orientation)

[Production Example 1]

(1) Preparation of magnesium compounds

The reaction tank (content 500 liters) with a stirrer was fully replaced with nitrogen, 97.2 kg of ethanol, 640 g of iodine and 6.4 kg of magnesium metal were added, and the reaction was carried out under stirring and reflux conditions until hydrogen was no longer generated in the system to obtain a solid reaction product. The reaction solution containing the solid reaction product was dried under reduced pressure to obtain the target magnesium compound (solid catalyst carrier).

(2) Preparation of solid titanium catalyst component

In a reaction tank (500 liters of internal volume) equipped with a stirrer after sufficient nitrogen substitution, 30 kg of the above-mentioned magnesium compound (unground), 150 liters of refined heptane (n-heptane), 4.5 liters of silicon tetrachloride, and 5.4 liters of di-n-butyl phthalate were added. The system was maintained at 90°C, and 144 liters of titanium tetrachloride were added under stirring. After reacting at 110°C for 2 hours, the solid component was separated and washed with refined heptane at 80°C. 228 liters of titanium tetrachloride were added, reacted at 110°C for 2 hours, and then fully washed with refined heptane to obtain a solid titanium catalyst component.

(3) Preparation of prepolymerized catalyst

10 mmol of triethylaluminum, 2 mmol of dicyclopentyldimethoxysilane and 1 mmol of the solid titanium catalyst component obtained in (2) above in terms of titanium atom were added to 200 mL of heptane. The internal temperature was maintained at 20° C. and propylene was continuously introduced under stirring. Stirring was stopped after 60 minutes, and a prepolymerized catalyst slurry in which 4.0 g of propylene was polymerized per 1 g of the solid titanium catalyst component was obtained.

(4) Main aggregation

336 liters of propylene were added to a 600 liter autoclave and the temperature was raised to 60°C. Then 8.7 mL of triethylaluminum, 11.4 mL of dicyclopentyldimethoxysilane, and 2.9 g of the prepolymerized catalyst slurry obtained in (3) above were added as a solid titanium catalyst component to start polymerization. 75 minutes after the start of polymerization, the temperature was lowered to 50°C over 10 minutes (first stage polymerization was completed).

The intrinsic viscosity [η] of the propylene polymer (a1-1) obtained by polymerization 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. Next, the vent valve was opened to discharge unreacted propylene through a cumulative flow meter (end of the second stage polymerization).

Thus, 51.8 kg of powdered propylene polymer was obtained. The proportion of the propylene polymer (a1-1) generated by the first stage polymerization in the above-mentioned propylene polymer calculated by material balance was 25% by mass, the proportion of the propylene polymer (a2-1) generated by the second stage polymerization was 75% by mass, and the intrinsic viscosity [η] was 0.99 dl/g.

To the propylene polymer, 2000 ppm of IRGANOX 1010 (manufactured by BASF), 2000 ppm of IRGAFOS 168 (manufactured by BASF), 1000 ppm of SANDSTAB P-EPQ (manufactured by Clariant Japan K.K.) as antioxidants and 1000 ppm of calcium stearate as a neutralizing agent were added, and melt-kneaded using a twin-screw extruder to obtain a pelletized propylene polymer (A-1). The MFR of the propylene polymer (A-1) finally obtained in this manner was 1.2 g/10 minutes.

Table 1 summarizes the physical properties of the polymer obtained in Production Example 1.

[Table 1]

Table 1

[Production Example 2]

(1) Preparation of magnesium compounds

The reaction tank (content 500 liters) with a stirrer was fully replaced with nitrogen, 97.2 kg of ethanol, 640 g of iodine and 6.4 kg of magnesium metal were added, and the mixture was reacted under stirring and reflux conditions until no hydrogen was generated in the system to obtain a solid reaction product. The reaction solution containing the solid reaction product was dried under reduced pressure to obtain the target magnesium compound (solid catalyst carrier).

(2) Preparation of solid titanium catalyst component

In a reaction tank (500 liters of internal volume) equipped with a stirrer after sufficient nitrogen substitution, 30 kg of the above-mentioned magnesium compound (unground), 150 liters of refined heptane (n-heptane), 4.5 liters of silicon tetrachloride, and 5.4 liters of di-n-butyl phthalate were added. The system was maintained at 90°C, and 144 liters of titanium tetrachloride were added under stirring. After reacting at 110°C for 2 hours, the solid component was separated and washed with refined heptane at 80°C. 228 liters of titanium tetrachloride were added, reacted at 110°C for 2 hours, and then fully washed with refined heptane to obtain a solid titanium catalyst component.

(3) Pretreatment

In a reaction tank with a stirring device having an internal volume of 500 liters, 230 liters of purified heptane was added, 25 kg of the above solid catalyst component was supplied, triethylaluminum was supplied at a ratio of 1.0 mol/mol relative to the titanium atom in the solid catalyst component, and dicyclopentyldimethoxysilane was supplied at a ratio of 1.8 mol/mol relative to the titanium atom in the solid catalyst component. Propylene was then introduced until the propylene partial pressure reached 0.3 kgf/ ^cm2G , and the reaction was carried out at 25°C for 4 hours. After the reaction was completed, the solid catalyst component was washed several times with purified heptane, and carbon dioxide was supplied, and stirring was carried out for 24 hours.

(4) Aggregation

Into a polymerization apparatus with an internal volume of 200 liters and equipped with a stirrer, the treated solid catalyst component was supplied at 3 mmol/hr in terms of titanium atoms in the component, triethylaluminum was supplied at 4 mmol/kg-PP, and dicyclopentyldimethoxysilane was supplied at 1 mmol/kg-PP, and propylene, ethylene, 1-butene and hydrogen were reacted under the conditions of a polymerization temperature of 80°C and a polymerization pressure (total pressure) of 28 kgf/ ^cm2G . At this time, the supply amounts of ethylene and 1-butene and the supply amounts of hydrogen were adjusted so as to achieve the desired contents of ethylene and 1-butene and MFR. The composition analysis values (gas chromatography analysis) of the gas portion in the polymerization apparatus showed an ethylene concentration of 3.5 mol%, a 1-butene concentration of 4.9 mol%, and a hydrogen concentration of 2.5 mol%.

To the propylene-ethylene-1-butene copolymer thus obtained were added 2000 ppm of IRGANOX 1010 (manufactured by BASF), 2000 ppm of IRGAFOS 168 (manufactured by BASF), 1000 ppm of SANDSTAB P-EPQ (manufactured by Clariant Japan K.K.) as antioxidants, and 1000 ppm of calcium stearate as a neutralizing agent, and the mixture was melt-kneaded using a twin-screw extruder to obtain a granular propylene-ethylene-1-butene random copolymer (B-1).

[Production Example 3]

The ethylene supply amount, 1-butene supply amount and hydrogen supply amount were adjusted so that the composition analysis values (gas chromatography analysis) of the gas portion in the polymerization device in "(4) Polymerization" showed an ethylene concentration of 2.0 mol%, a 1-butene concentration of 0 mol% and a hydrogen concentration of 5.5 mol%. Except for this, the same method as in Production Example 2 was carried out to obtain a granular propylene-ethylene random copolymer (B-2).

[Production Example 4]

The ethylene supply amount, 1-butene supply amount and hydrogen supply amount were adjusted so that the composition analysis values (gas chromatography analysis) of the gas portion in the polymerization device in "(4) Polymerization" showed an ethylene concentration of 1.6 mol%, a 1-butene concentration of 0 mol% and a hydrogen concentration of 4.2 mol%. Except for this, the same method as in Production Example 2 was carried out to obtain a granular propylene-ethylene random copolymer (B-3).

[Production Example 5]

The ethylene supply amount, 1-butene supply amount and hydrogen supply amount were adjusted so that the composition analysis values (gas chromatography analysis) of the gas portion in the polymerization device in "(4) Polymerization" showed an ethylene concentration of 1.7 mol%, a 1-butene concentration of 4.0 mol% and a hydrogen concentration of 2.3 mol%. Except for this, the same method as in Production Example 2 was carried out to obtain a granular propylene-ethylene-1-butene random copolymer (B-4).

[Production Example 6]

The ethylene supply amount, 1-butene supply amount and hydrogen supply amount were adjusted so that the composition analysis values (gas chromatography analysis) of the gas portion in the polymerization device in "(4) Polymerization" showed an ethylene concentration of 1.3 mol%, a 1-butene concentration of 0 mol% and a hydrogen concentration of 3.5 mol%. Except for this, the same method as in Production Example 2 was carried out to obtain a granular propylene-ethylene random copolymer (B-5).

[Production Example 7: F-704NP]

The product used was "Prime Polypro F-704NP" manufactured by Prime Polymer Co., Ltd. For convenience, this is described as a production example.

Table 2 summarizes the physical properties of the polymers obtained in Production Examples 2 to 7.

[Table 2]

Table 2

[Examples of the first aspect of the present invention and comparative examples thereof]

[Example 1-1]

5 parts by mass of the propylene-based polymer (A-1) obtained in Preparation Example 1 and 95 parts by mass of the propylene-ethylene-1-butene random copolymer (B-1) obtained in Preparation Example 2 were used to prepare a 25 μm thick non-stretched film under the following molding conditions using a non-stretched film forming machine having a single-layer die head with a width of 600 mm connected to an extruder (1 unit) with a screw diameter of 75 mm.

Resin temperature: 248°C

Cooling roller temperature: 30°C

Forming speed: 150m/min

Table 3 shows the physical properties of the film.

[Example 1-2, Comparative Examples 1-1 to 1-6]

Except having changed the compounding composition as described in Table 3, it carried out similarly to Example 1-1, and produced the non-stretched film.

[table 3]

table 3

[Examples of the second aspect of the present invention and comparative examples thereof]

[Example 2-1]

5 parts by mass of the propylene-based polymer (A-1) obtained in Preparation Example 1 and 95 parts by mass of the propylene-ethylene random copolymer (B-3) obtained in Preparation Example 4 were used to prepare a 25 μm thick non-stretched film under the following molding conditions using a non-stretched film molding machine having a single-layer die head with a width of 600 mm connected to an extruder (1 unit) with a screw diameter of 75 mm.

Resin temperature: 248°C

Cooling roller temperature: 30°C

Forming speed: 150m/min

Table 4 shows the physical properties of the film.

[Examples 2-2 to 2-5, Comparative Examples 2-1 to 2-8]

Except having changed the compounding composition as described in Table 4, it carried out similarly to Example 2-1, and produced the non-stretched film.

The above results are summarized in Table 4.

[Table 4]

Claims (8)

1. A non-stretched film, characterized in that: It is formed from a propylene polymer composition (X1), The propylene polymer composition (X1) contains a propylene polymer (A) and a propylene-α-olefin copolymer (B1). The propylene polymer (A) contains: 20 to 50% by weight of a propylene polymer (a1) having an intrinsic viscosity [η] in the range of 10 to 12 dl/g as measured at 135° C. in a tetralin solvent; and 50 to 80% by weight of a propylene polymer (a2) having an intrinsic viscosity [η] in the range of 0.5 to 1.5 dl/g as measured at 135° C. in a tetralin solvent, wherein the total amount of the propylene polymer (a1) and the propylene polymer (a2) is 100% by weight. The propylene-α-olefin copolymer (B1) has a melt flow rate of 0.1 to 30 g/10 min measured at 230° C. and a load of 2.16 kg, and an intrinsic viscosity [η] measured at 135° C. in a tetralin solvent of higher than 1.5 dl/g and not more than 5.0 dl/g, wherein the propylene-α-olefin copolymer (B1) contains 5.5 mol % or more of a structural unit derived from an α-olefin, wherein the α-olefin does not include propylene, The content of the propylene polymer (A) is 1 to 10 parts by mass and the content of the propylene-α-olefin copolymer (B1) is 90 to 99 parts by mass based on 100 parts by mass of the total of the propylene polymer (A) and the propylene-α-olefin copolymer (B1). 2. A non-stretched film, characterized in that: It is formed from a propylene polymer composition (X2), The propylene polymer composition (X2) contains a propylene polymer (A) and a propylene-α-olefin copolymer (B2). The propylene polymer (A) contains: 20 to 50% by weight of a propylene polymer (a1) having an intrinsic viscosity [η] in the range of 10 to 12 dl/g as measured at 135° C. in a tetralin solvent; and 50 to 80% by weight of a propylene polymer (a2) having an intrinsic viscosity [η] in the range of 0.5 to 1.5 dl/g as measured at 135° C. in a tetralin solvent, wherein the total amount of the propylene polymer (a1) and the propylene polymer (a2) is 100% by weight. The propylene-α-olefin copolymer (B2) has a melt flow rate of 0.1 to 30 g/10 min measured at 230° C. and a load of 2.16 kg, and an intrinsic viscosity [η] measured at 135° C. in a tetralin solvent of higher than 1.5 dl/g and lower than 5.0 dl/g, wherein the propylene-α-olefin copolymer (B2) contains 1 mol % or more and less than 5.5 mol % of a structural unit derived from an α-olefin, wherein the α-olefin does not include propylene, The content of the propylene polymer (A) is 1 to 18 parts by mass and the content of the propylene-α-olefin copolymer (B2) is 82 to 99 parts by mass based on 100 parts by mass of the total of the propylene polymer (A) and the propylene-α-olefin copolymer (B2). 3. The non-stretched film according to claim 1 or 2, characterized in that: The propylene polymer (A) has a melt flow rate (MFR) of 0.01 to 5 g/10 min as measured at 230° C. and a load of 2.16 kg. 4. The non-stretched film according to claim 1 or 2, characterized in that: The propylene polymer (A) has a high molecular weight region having a molecular weight of 1,500,000 or more, which accounts for 7% or more of the total area of the region enclosed by the molecular weight distribution curve measured by gel permeation chromatography (GPC). 5. The non-stretched film according to claim 1 or 2, characterized in that: The propylene polymer (A) has two peaks in a molecular weight distribution curve measured by GPC, and a ratio (MH/ML) of a high molecular weight peak molecular weight MH to a low molecular weight peak molecular weight ML is 50 or more. 6. The non-stretched film according to claim 1 or 2, characterized in that: The axial orientation degree of the PP (110) plane determined by wide-angle X-ray diffraction measurement is 0.85 or more. 7. A sealing film, characterized in that: The sealing film is a laminated body having a sealing film main body and a surface layer in sequence. The surface layer is the non-stretched film according to claim 1. 8. A multi-layer sealing film, characterized in that: The multi-layer sealing film is a laminate having an outer layer, an intermediate layer and a sealing layer in sequence. The intermediate layer is the non-stretched film according to claim 2.