KR20220101758A - Biaxially oriented polypropylene film - Google Patents

Abstract

To provide a biaxially oriented laminated polypropylene film having higher heat resistance and rigidity. A polypropylene resin constituting the film satisfies the conditions of 1) to 4) below, and the lower limit of the plane orientation coefficient of the film is 0.0125, it is a biaxially oriented polypropylene film. 1) The lower limit of the mesopentad fraction is 96%. 2) The upper limit of the amount of copolymerization monomers other than propylene is 0.1 mol%. 3) The mass average molecular weight (Mw)/number average molecular weight (Mn) is 3.0 or more and 5.4 or less. 4) Melt flow rate (MFR) measured at 230°C and 2.16 kgf is 6.2 g/10 min or more and 9.0 g/10 min or less.

Description

Biaxially oriented polypropylene film {BIAXIALLY ORIENTED POLYPROPYLENE FILM}

The present invention relates to a biaxially oriented laminated polypropylene film. Specifically, it relates to a biaxially oriented polypropylene film excellent in heat resistance and mechanical properties.

DESCRIPTION OF RELATED ART Conventionally, the stretched film of polypropylene has been used universally for a wide range of uses, such as the object for packaging of foodstuff and various goods, the object for electrical insulation, and a surface protection film. However, the conventional polypropylene film has a shrinkage rate of several tens of % at 150°C, and has low heat resistance and low rigidity as compared with a polyethylene terephthalate (PET) film and the like, so that its use has been limited.

Various techniques for improving the physical properties of the polypropylene film have been proposed. For example, by making a film using polypropylene containing almost the same amount of high molecular weight component and low molecular weight component (or low molecular weight component is small), the molecular weight distribution is wide, and the decalin soluble content is small, the rigidity and workability are balanced. The technique is known (patent document 1). However, with this technique, it cannot be said that the heat resistance at high temperature exceeding 150 degreeC is still sufficient, it has high heat resistance, and the polypropylene film excellent in impact resistance and transparency is not known.

As a result of intensive studies based on the above prior art, the applicant of the present application has succeeded in providing a stretched polypropylene film having high rigidity and high heat resistance by using a polypropylene-based polymer having a mesopentad fraction of 96% or more ( Patent Document 2). However, this film had room for improvement in heat resistance.

Japanese Patent Publication No. 2008-540815 WO2015/012324 pamphlet

In view of the above circumstances, the present invention set forth as a subject the provision of a biaxially oriented laminated polypropylene film having higher heat resistance and rigidity.

The present invention capable of solving the above problems is a biaxially oriented polypropylene film characterized in that the polypropylene resin constituting the film satisfies the following conditions 1) to 4) and the lower limit of the plane orientation coefficient of the film is 0.0125 to be.

1) The lower limit of the mesopentad fraction is 96%.

2) The upper limit of the amount of copolymerization monomers other than propylene is 0.1 mol%.

3) The mass average molecular weight (Mw)/number average molecular weight (Mn) is 3.0 or more and 5.4 or less.

4) Melt flow rate (MFR) measured at 230°C and 2.16 kgf is 6.2 g/10 min or more and 9.0 g/10 min or less.

In addition, the second invention, which was able to solve the above problems, is a surface layer (A) containing a polypropylene-based resin as a main component and a surface layer ( B), and the polypropylene resin constituting the base layer (A) satisfies the conditions of 1) to 4) below, and the lower limit of the plane orientation coefficient of the film is 0.0125, A biaxially oriented polypropylene film characterized in that .

1) The lower limit of the mesopentad fraction is 96%.

2) The upper limit of the amount of copolymerization monomers other than propylene is 0.1 mol%.

3) The mass average molecular weight (Mw)/number average molecular weight (Mn) is 3.0 or more and 5.4 or less.

4) Melt flow rate (MFR) measured at 230°C and 2.16 kgf is 6.2 g/10 min or more and 9.0 g/10 min or less.

In this case, it is suitable that the thermal contraction rate at 150 degreeC of the longitudinal direction and the transverse direction of the said film is 8 % or less.

In this case, it is suitable that the tensile elastic modulus of the said film is 2.0 GPa or more in the longitudinal direction, and the tensile elastic modulus of the transverse direction of a film is 4.5 GPa or more.

In this case, it is suitable that the haze value of the said film is 5 % or less.

Since the biaxially oriented polypropylene film of the present invention has a small molecular weight distribution and less entanglement of molecular chains, the orientation becomes stronger, has higher thermal dimensional stability and lateral stiffness, and has smaller thermal deformation wrinkles, Since it is hard to cut, it is very excellent in film processability.

The biaxially oriented polypropylene film of the first invention is characterized in that the polypropylene resin constituting the film satisfies the following conditions 1) to 4) and the lower limit of the plane orientation coefficient of the film is 0.0125.

1) The lower limit of the mesopentad fraction is 96%.

2) The upper limit of the amount of copolymerization monomers other than propylene is 0.1 mol%.

3) The mass average molecular weight (Mw)/number average molecular weight (Mn) is 3.0 or more and 5.4 or less.

4) Melt flow rate (MFR) measured at 230°C and 2.16 kgf is 6.2 g/10 min or more and 9.0 g/10 min or less.

Further, the biaxially oriented polypropylene film of the second invention has a surface layer containing a polypropylene resin as a main component on at least one surface of a substrate layer (A) containing a polypropylene resin as a main component and a substrate layer (A) as a main component. It has (B), and the polypropylene resin which comprises a base material layer (A) satisfy|fills the conditions of following 1) - 4), It is characterized by the lower limit of the plane orientation coefficient of a film being 0.0125.

1) The lower limit of the mesopentad fraction is 96%.

2) The upper limit of the amount of copolymerization monomers other than propylene is 0.1 mol%.

3) The mass average molecular weight (Mw)/number average molecular weight (Mn) is 3.0 or more and 5.4 or less.

4) Melt flow rate (MFR) measured at 230°C and 2.16 kgf is 6.2 g/10 min or more and 9.0 g/10 min or less.

It will be described in more detail below.

(1) As the polypropylene resin used in the first invention, a polypropylene resin copolymerized with ethylene and/or α-olefin having 4 or more carbon atoms in an amount of 0.5 mol% or less can also be used. Such a copolymerized polypropylene resin is also included in the polypropylene resin (hereinafter, polypropylene resin) of the present invention. 0.3 mol% or less of a copolymerization component is preferable, 0.1 mol% or less is more preferable, and the perfect homopolypropylene resin which does not contain a copolymerization component is the most preferable.

When ethylene and/or ?-olefin having 4 or more carbon atoms are copolymerized in an amount exceeding 0.5 mol%, crystallinity and rigidity may fall too much, and thermal contraction rate at high temperature may become large. You may blend and use such resin.

It is preferable that the mesopentad fraction ([mm mm]%) measured by ¹³ C-NMR which is a stereoregularity index of the polypropylene resin is 96 to 99.5%. More preferably, it is 97 % or more, More preferably, it is 98 % or more. When the mesopentad fraction of polypropylene of a base material layer (A) is small, an elasticity modulus becomes low and there exists a possibility that heat resistance may become inadequate. 99.5% is a realistic upper limit.

Moreover, as for Mw/Mn which is a parameter|index of molecular weight distribution, 3.0-5.4 are preferable in polypropylene resin. More preferably, it is 3.0-5.0, More preferably, it is 3.2-4.5, Especially preferably, it is 3.3-4.0.

When Mw/Mn of the entire polypropylene resin constituting the biaxially oriented polypropylene film of the present invention exceeds 5.4, when Mw/Mn becomes too large, high molecular weight components increase, and thermal shrinkage may increase, or in the width direction ( TD) tends to decrease in tensile modulus (Young's modulus) in some cases. When a high molecular weight component exists, although a high molecular weight component accelerates|stimulates the crystallization of a low molecular weight component, entanglement between molecules becomes strong and there also exists a tendency for thermal contraction rate to become large even if crystallinity is high.

If Mw/Mn of the whole polypropylene resin which comprises the biaxially-oriented polypropylene film of this invention is less than 3.0, film forming will become difficult.

Mw means a mass average molecular weight, and Mn means a number average molecular weight.

As for the mass average molecular weight (Mw) of polypropylene resin, 180,000-500,000 are preferable. A more preferable lower limit of Mw is 190,000, more preferably 200,000, and a more preferable upper limit of Mw is 320,000, more preferably 300,000, particularly preferably 250,000.

As for the number average molecular weight (Mn) of polypropylene resin, 20,000-200,000 are preferable. A more preferable lower limit of Mn is 30,000, more preferably 40,000, particularly preferably 50,000, and a more preferable upper limit of Mn is 80,000, more preferably 70,000, particularly preferably 60,000.

When the gel permeation chromatography (GPC) integration curve of the entire polypropylene resin constituting the biaxially oriented polypropylene film of the first invention is measured, the lower limit of the amount of the component having a molecular weight of 100,000 or less is preferably 35% by mass. , More preferably, it is 38 mass %, More preferably, it is 40 mass %, Especially preferably, it is 41 mass %, Most preferably, it is 42 mass %.

On the other hand, the upper limit of the amount of the component with a molecular weight of 100,000 or less in the GPC integration curve is preferably 65 mass%, more preferably 60 mass%, still more preferably 58 mass%, particularly preferably 56 mass%. %, and most preferably 55 mass%. If it is the said range, extending|stretching becomes easy, thickness nonuniformity becomes small, or extending|stretching temperature and heat setting temperature rise easily, and thermal contraction rate can be suppressed lower.

It is preferable that the melt flow rate (MFR; 230 degreeC, 2.16 kgf) of the polypropylene resin at this time is 6.2 g/10 min - 10.0 g/10 min.

The lower limit of the MFR of the polypropylene resin is more preferably 6.5 g/10 min, still more preferably 7 g/10 min, particularly preferably 7.5 g/10 min. As for the upper limit of MFR of a polypropylene resin, it is more preferable that it is 9 g/10min, It is still more preferable that it is 8.5 g/10min, It is especially preferable that it is 8.2 g/10min.

If the melt flow rate (MFR; 230°C, 2.16 kgf) is 6.2 g/10 min or more, the thermal shrinkage rate at high temperature can also be made smaller. Moreover, since the degree of orientation of the film which arises by extending|stretching becomes strong, the rigidity of a film, especially the tensile modulus (Young's modulus) of the width (TD) direction becomes high. In addition, if the melt flow rate (MFR; 230°C, 2.16 kgf) is 9.0 g/10 min or less, it is easy to form a film without fracture.

In addition, the molecular weight distribution of the polypropylene resin is determined by polymerizing components of different molecular weights in a series of plants in multiple stages, blending components of different molecular weights off-line with a kneader, blending catalysts with different performance to polymerize, or desired molecular weight distribution It is possible to adjust by using a catalyst that can realize

The polypropylene resin used by this invention is obtained by polymerizing propylene of a raw material using well-known catalysts, such as a Ziegler-Natta catalyst and a metallocene catalyst. Especially, in order to eliminate a heterogeneous bond, it is preferable to use a Ziegler-Natta catalyst, and to use the catalyst which superposition|polymerization with high stereoregularity is possible.

As the polymerization method of propylene, a known method may be employed, for example, a method of polymerization in an inert solvent such as hexane, heptane, toluene, or xylene, a method of polymerization in a liquid monomer, a catalyst is added to a gaseous monomer, The method of superposing|polymerizing in a gaseous-phase state, the method of combining these and superposing|polymerizing, etc. are mentioned.

You may make polypropylene resin contain an additive and other resin. As an additive, antioxidant, a ultraviolet absorber, a nucleating agent, an adhesive, an antifog agent, a flame retardant, an inorganic or organic filler etc. are mentioned, for example. Examples of the other resin include a polypropylene resin other than the polypropylene resin used in the present invention, a random copolymer that is a copolymer of propylene and ethylene and/or an ?-olefin having 4 or more carbon atoms, and various elastomers. These are sequentially polymerized using a multi-stage reactor, blended with polypropylene resin and a Henschel mixer, or master pellets prepared in advance using a melt kneader are diluted with polypropylene to a predetermined concentration, or the entire amount is melt-kneaded in advance. you can use it.

(2) The polypropylene resin used for the base material layer (A) of 2nd invention can also use the polypropylene resin which copolymerized ethylene and/or the C4 or more alpha-olefin in 0.5 mol% or less. Such a copolymerized polypropylene resin is also included in the polypropylene resin (hereinafter, polypropylene resin) of the present invention. 0.3 mol% or less of a copolymerization component is preferable, 0.1 mol% or less is more preferable, and the perfect homopolypropylene resin which does not contain a copolymerization component is the most preferable.

When ethylene and/or ?-olefin having 4 or more carbon atoms are copolymerized in an amount exceeding 0.5 mol%, crystallinity and rigidity may fall too much, and thermal contraction rate at high temperature may become large. You may blend and use such resin.

It is preferable that the mesopentad fraction ([mm mm]%) measured by ¹³ C-NMR, which is a stereoregularity index of the polypropylene resin, is 96 to 99.5%. More preferably, it is 97 % or more, More preferably, it is 98 % or more. When the mesopentad fraction of polypropylene of a base material layer (A) is small, an elasticity modulus becomes low and there exists a possibility that heat resistance may become inadequate. 99.5% is a realistic upper limit.

Moreover, as for Mw/Mn which is a parameter|index of molecular weight distribution, 3.0-5.4 are preferable in polypropylene resin. More preferably, it is 3.0-5.0, More preferably, it is 3.2-4.5, Especially preferably, it is 3.3-4.0.

When Mw/Mn of the whole polypropylene resin constituting the base layer (A) exceeds 5.4, when Mw/Mn becomes too large, high molecular weight components increase and thermal shrinkage may increase, or tension in the width direction (TD) The elastic modulus (Young's modulus) tends to decrease in some cases.

When a high molecular weight component exists, although a high molecular weight component accelerates|stimulates the crystallization of a low molecular weight component, entanglement between molecules becomes strong and there also exists a tendency for thermal contraction rate to become large even if crystallinity is high.

If Mw/Mn of the whole polypropylene resin which comprises the biaxially-oriented polypropylene film of this invention is less than 3.0, film forming will become difficult. Mw means a mass average molecular weight, and Mn means a number average molecular weight.

As for the mass average molecular weight (Mw) of polypropylene resin, 180,000-500,000 are preferable. A more preferable lower limit of Mw is 190,000, more preferably 200,000, and a more preferable upper limit of Mw is 320,000, more preferably 300,000, particularly preferably 250,000.

As for the number average molecular weight (Mn) of polypropylene resin, 20,000-200,000 are preferable. A more preferable lower limit of Mn is 30,000, more preferably 40,000, particularly preferably 50,000, and a more preferable upper limit of Mn is 80,000, more preferably 70,000, particularly preferably 60,000.

When the gel permeation chromatography (GPC) integration curve of the whole polypropylene resin constituting the base layer (A) is measured, the lower limit of the amount of the component having a molecular weight of 100,000 or less is preferably 35 mass%, more preferably 38 mass %, More preferably, it is 40 mass %, Especially preferably, it is 41 mass %, Most preferably, it is 42 mass %.

On the other hand, the upper limit of the amount of the component with a molecular weight of 100,000 or less in the GPC integration curve is preferably 65 mass%, more preferably 60 mass%, still more preferably 58 mass%, particularly preferably 56 mass%. %, and most preferably 55 mass%. If it is the said range, extending|stretching becomes easy, thickness nonuniformity becomes small, or extending|stretching temperature and heat setting temperature rise easily, and thermal contraction rate can be suppressed lower.

It is preferable that the melt flow rate (MFR; 230 degreeC, 2.16 kgf) of the polypropylene resin at this time is 6.2 g/10 min - 10.0 g/10 min.

The lower limit of the MFR of the polypropylene resin is more preferably 6.5 g/10 min, still more preferably 7 g/10 min, particularly preferably 7.5 g/10 min. As for the upper limit of MFR of a polypropylene resin, it is more preferable that it is 9 g/10min, It is still more preferable that it is 8.5 g/10min, It is especially preferable that it is 8.2 g/10min.

If the melt flow rate (MFR; 230°C, 2.16 kgf) is 6.2 g/10 min or more, the thermal shrinkage rate at high temperature can also be made smaller. Moreover, since the degree of orientation of the film which arises by extending|stretching becomes strong, the rigidity of a film, especially the tensile modulus (Young's modulus) of the width (TD) direction becomes high. In addition, if the melt flow rate (MFR; 230°C, 2.16 kgf) is 9.0 g/10 min or less, it is easy to form a film without fracture.

In addition, the molecular weight distribution of the polypropylene resin is determined by polymerizing components of different molecular weights in a series of plants in multiple stages, blending components of different molecular weights off-line with a kneader, blending catalysts with different performance to polymerize, or desired molecular weight distribution It is possible to adjust by using a catalyst that can realize

The polypropylene resin used in the base material layer (A) is obtained by polymerizing the propylene of a raw material using well-known catalysts, such as a Ziegler-Natta catalyst and a metallocene catalyst. Especially, in order to eliminate a heterogeneous bond, it is preferable to use a Ziegler-Natta catalyst, and to use the catalyst which superposition|polymerization with high stereoregularity is possible.

As the polymerization method of propylene, a known method may be employed, for example, a method of polymerization in an inert solvent such as hexane, heptane, toluene, or xylene, a method of polymerization in a liquid monomer, a catalyst is added to a gaseous monomer, The method of superposing|polymerizing in a gaseous-phase state, the method of combining these and superposing|polymerizing, etc. are mentioned.

You may make polypropylene resin contain an additive and other resin. As an additive, antioxidant, a ultraviolet absorber, a nucleating agent, an adhesive, an antifog agent, a flame retardant, an inorganic or organic filler etc. are mentioned, for example. Examples of the other resin include a polypropylene resin other than the polypropylene resin used in the present invention, a random copolymer that is a copolymer of propylene and ethylene and/or an ?-olefin having 4 or more carbon atoms, and various elastomers. These are sequentially polymerized using a multi-stage reactor, blended with polypropylene resin and a Henschel mixer, or master pellets prepared in advance using a melt kneader are diluted with polypropylene to a predetermined concentration, or the entire amount is melt-kneaded in advance. you can use it.

(3) It is preferable that the surface roughness of the surface of the surface layer (B) of 2nd invention is 0.027 micrometer or more and 0.40 micrometer or less. If it is less than 0.027 micrometer, adhesiveness with a printing ink or adhesiveness with the adhesive agent used for lamination with another member film is not enough, but when it exceeds 0.40 micrometer, the problem of color development and discoloration arises.

In order for the surface roughness of the surface of the surface layer (B) to be 0.027 µm or more and 0.40 µm or less, as a polypropylene-based resin composition for forming the surface layer (B), two or more types of polypropylene-based resins having different melt flow rates (MFR) Preference is given to using mixtures. In this case, it is preferable that it is 3 g/10min or more, and, as for the difference of MFR, it is more preferable that it is 3.5g/10min or more.

By using such a mixture, it is estimated that the surface roughness of the surface of the surface layer (B) will be 0.027 µm or more due to the difference in the crystallization rate.

As the polypropylene-based resin having a larger MFR, a polypropylene copolymerized with ethylene and/or an α-olefin having 4 or more carbon atoms can also be used. Examples of the α-olefin having 4 or more carbon atoms include 1-butene, 1-hexene, 4-methyl·1-pentene, and 1-octene.

Further, as the polypropylene-based resin having a smaller MFR, a polypropylene obtained by copolymerizing ethylene and/or an ?-olefin having 4 or more carbon atoms can also be used. Examples of the α-olefin having 4 or more carbon atoms include 1-butene, 1-hexene, 4-methyl·1-pentene, and 1-octene.

Moreover, you may use maleic acid etc. which have polarity as another copolymerization component.

It is preferable that ethylene, C4 or more alpha-olefin, and other copolymerization components are 8.0 mol% or less in total. When it copolymerizes exceeding 8.0 mol%, a film may whiten and an external appearance may become unsatisfactory, or adhesiveness may generate|occur|produce and film forming may become difficult.

In addition, you may use these resin in mixture of 2 or more types. In the case of blending, the individual resins may be copolymerized in an amount exceeding 8.0 mol%, but the blend is preferably 8.0 mol% or less of monomers other than propylene in monomer units.

Moreover, it is preferable that MFR of the polypropylene resin composition of a surface layer (B) is 1.0 g/10min - 8 g/10min. As for the minimum of MFR of the polypropylene resin composition of a surface layer (B), it is more preferable that it is 2 g/10min, and it is still more preferable that it is 3g/10min. As for the upper limit of MFR of the polypropylene resin composition of a surface layer (B), it is more preferable that it is 7 g/10min, and it is still more preferable that it is 6.0 g/10min. If it is this range, film forming property is also favorable and the thermal contraction rate in high temperature can also be kept small. When the MFR of the polypropylene resin composition of the surface layer (B) is less than 1.0 g/10 min, when the MFR of the polypropylene of the substrate layer (A) is large, the viscosity difference between the substrate layer (A) and the surface layer (B) becomes large. , it becomes easy to generate|occur|produce nonuniformity (fabric nonuniformity) at the time of film forming. When the MFR of the polypropylene resin composition of the surface layer (B) exceeds 8 g/10 min, the adhesion to the cooling roll deteriorates, air is mixed, the smoothness is poor, and there is a fear that the defects used as the starting point increase.

The polypropylene resin used in the surface layer (B) is obtained by polymerizing the propylene of a raw material using well-known catalysts, such as a Ziegler-Natta catalyst and a metallocene catalyst. Especially, in order to eliminate a heterogeneous bond, it is preferable to use a Ziegler-Natta catalyst, and to use the catalyst which superposition|polymerization with high stereoregularity is possible.

As the polymerization method of propylene, a known method may be employed, for example, a method of polymerization in an inert solvent such as hexane, heptane, toluene, or xylene, a method of polymerization in a liquid monomer, a method of polymerization in a liquid monomer, a catalyst is added to a gaseous monomer, The method of superposing|polymerizing in a gaseous-phase state, the method of combining these and superposing|polymerizing, etc. are mentioned.

You may make the surface layer (B) contain an additive and other resin. As an additive, antioxidant, a ultraviolet absorber, a nucleating agent, an adhesive, an antifog agent, a flame retardant, an inorganic or organic filler etc. are mentioned, for example. Examples of the other resin include a polypropylene resin other than the polypropylene resin used in the present invention, a random copolymer that is a copolymer of propylene and ethylene and/or an ?-olefin having 4 or more carbon atoms, and various elastomers. These are sequentially polymerized using a multi-stage reactor, blended with polypropylene resin and a Henschel mixer, or master pellets prepared in advance using a melt kneader are diluted with polypropylene to a predetermined concentration, or the entire amount is melt-kneaded in advance. you can use it.

It is preferable that the wetting tension of the surface of a surface layer (B) is 38 mN/m or more.

If the wetting tension is 38 mN/m or more, the adhesion with the printing ink or the adhesive is improved.

As for the wetting tension, it is more preferable that it is 16 Logohm or more. In order to set the wetting tension to 38 mN/m or more, the use of additives such as antistatic agents and surfactants is usually performed. can

For example, in corona treatment, it is preferable to perform in the air using a preheating roll and a treatment roll.

It is preferable that the central plane peak height SRp + central plane trough depth SRv of the surface of the surface layer (B) of the biaxially oriented polypropylene-based film of the present invention is 1.0 µm or more and 2.0 µm or less.

Here, the surface roughness of the surface of the surface layer (B), the central plane peak height SRp, and the central plane trough depth SRv are measured using a three-dimensional roughness meter, with a stylus pressure of 20 mg, a measurement length of 1 mm in the X direction, and a feed pitch of 2 in the Y direction. It is calculated|required according to the definition of arithmetic mean roughness described in JISB0601 (1994) by measuring 99 lines in micrometer, 20,000 times of height direction magnification, and cutoff 80 micrometers.

The central plane peak height SRp + the central plane trough depth SRv of the surface of the surface layer (B) is an index of the state of the large uneven portion formed by the lubricant, and in the state of the roll film, sliding at the time of contact with the base layer (A) related to sex

If the surface of the surface layer (B) has a central plane peak height SRp + central plane valley depth SRv of 1.0 µm or more, the unwinding property from the roll film is improved, and if it is 2.0 µm or less, transparency is maintained.

1.1 micrometers or more are preferable, as for center plane peak height SRp + center plane trough depth SRv of the surface of the surface layer (B), 1.2 micrometers or more are more preferable, and 1.3 micrometers or more are especially preferable.

In order for the central plane peak height SRp + central plane valley depth SRv of the surface of the surface layer (B) to be 1.0 µm or more and 2.0 µm or less, it is a suitable method to mix an anti-blocking agent with the polypropylene resin composition forming the surface layer (B). .

As the anti-blocking agent, it can be appropriately selected from inorganic anti-blocking agents such as silica, calcium carbonate, kaolin, and zeolite, and organic anti-blocking agents such as acrylic, polymethacrylic, and polystyrene-based anti-blocking agents. Among these, it is especially preferable to use silica.

The preferred average particle diameter of the anti-blocking agent is 1.0 to 2.0 µm, more preferably 1.0 to 1.5 µm.

It is preferable that an anti-blocking agent sets it as 3000 ppm by mass in a polypropylene resin composition. The measuring method of the average particle diameter here refers to taking a picture with a scanning electron microscope, measuring the ferret diameter in the horizontal direction using an image analyzer, and expressing it as the average value.

(4) biaxially oriented polypropylene film

9-200 m is preferable, as for the thickness of the whole biaxially-oriented polypropylene film of this invention, 10-150 micrometers is more preferable, 12-100 micrometers is still more preferable, 12-80 micrometers is especially preferable.

As a ratio of the thickness of the surface layer (B) and the base material layer (A) in the biaxially oriented polypropylene film of 2nd invention, it is preferable that all surface layer (B)/all base material layer (A) are 0.01-0.5, It is more preferable that it is 0.03-0.4, and it is still more preferable that it is 0.05-0.3. When all the surface layers (B)/all the base material layers (A) exceed 0.5, the tendency for a shrinkage rate to become large will be shown. Moreover, it is preferable that the thickness of the whole base material layer (A) with respect to the thickness of the whole film is 50 to 99 %, More preferably, it is 60 to 97 %, Especially preferably, it is 70 to 95 %. The remainder becomes the surface layer (B) or the surface layer (B) and other layers (eg, C layer). 0.5-4 micrometers is preferable, as for the substantial thickness of the whole surface layer (B), 1-3.5 micrometers is more preferable, 1.5-3 micrometers is still more preferable.

As a ratio of the thickness of the surface layer (B) and the base material layer (A) in the biaxially oriented polypropylene film of 2nd invention, it is preferable that the whole surface layer (B)/all the base material layers (A) are 0.01-0.5, It is more preferable that it is 0.03-0.4, and it is still more preferable that it is 0.05-0.3. When all the surface layers (B)/all the base material layers (A) exceed 0.5, the tendency for a shrinkage|contraction to become large will be shown. Moreover, it is preferable that the thickness of the whole base material layer (A) with respect to the thickness of the whole film is 50 to 99 %, More preferably, it is 60 to 97 %, Especially preferably, it is 70 to 95 %. The remainder becomes the surface layer (B) or the surface layer (B) and other layers (eg, layer C).

0.5-4 micrometers is preferable, as for the substantial thickness of the whole surface layer (B), 1-3.5 micrometers is more preferable, 1.5-3 micrometers is still more preferable.

Although the biaxially-oriented polypropylene film of 2nd invention may be a film of the two-layer structure which has a base material layer (A) and a surface layer (B) one by one, it is good also as a structure of three or more layers. What is preferable is the two-layer structure of a base material layer (A)/surface layer (B). Moreover, the three-layer structure of surface layer (B)/A-layer/surface layer (B), /base layer (A)/intermediate|middle layer (C)/surface layer (B), or more multilayer structure may be sufficient.

In addition, when there are two or more base material layers (A) and surface layers (B), as long as each layer satisfy|fills the characteristic, a composition may differ.

(5) Film properties

It is preferable that it is 8 % or less, and, as for the thermal contraction rate in 150 degreeC of the longitudinal direction and the horizontal direction of the biaxially-oriented polypropylene film of this invention, it is more preferable that it is 7 % or less. When the heat shrinkage rate is 8% or less, the heat distortion wrinkles at the time of processing can be reduced.

In the biaxially-oriented polypropylene film of this invention, it is preferable that the thermal contraction rate of the longitudinal direction in 150 degreeC is 0.2 to 8 %, and 0.3 to 7 % is more preferable. It can be said that it is a film excellent in heat resistance as thermal contraction rate is the said range, and it can use also in the use which may be exposed to high temperature. In addition, if the thermal contraction rate of 150°C is up to about 1.5%, it is possible, for example, by adjusting the stretching conditions and heat setting conditions to increase the low molecular weight component. desirable.

In the biaxially-oriented polypropylene film of this invention, it is preferable that the thermal contraction rate in the transverse direction in 150 degreeC is 0.2 to 8 %, 0.3 to 7 % is more preferable, 0.4 to 6 % is still more preferable, 0.5 to 5% is particularly preferred. It can be said that it is a film especially excellent in heat resistance as thermal contraction rate is the said range, and it can be used also for the use which may be exposed to high temperature. In addition, if the thermal contraction rate of 150°C is up to about 1.5%, it is possible, for example, by adjusting the stretching conditions and heat setting conditions to increase the low molecular weight component. desirable.

It is preferable that the tensile elastic modulus of the longitudinal direction of the biaxially-oriented polypropylene film of this invention is 1.8-4 GPa, It is more preferable that it is 2.1-3.7 GPa, It is still more preferable that it is 2.2-3.5 GPa, 2.3-3.4 GPa is particularly preferred. The measurement method will be described later.

It is preferable that the tensile elasticity modulus of the transverse direction of the biaxially-oriented polypropylene film of this invention is 4.5-8 GPa, It is more preferable that it is 4.6-7.5 GPa, It is still more preferable that it is 4.7-7 GPa, 4.8-6.5 GPa is particularly preferred. If the tensile modulus of elasticity in the transverse direction is within the above range, it becomes possible to obtain a film that is difficult to fold.

The folding difficulty of the biaxially oriented polypropylene film of the present invention was evaluated by holding the film in a ring shape and compressing it, and the drag force was evaluated by a ring crush measurement value detected by a load cell. The measurement method will be described later.

5 % or less is preferable, as for the haze of the biaxially-oriented polypropylene film of this invention, 0.2 to 5 % is more preferable, 0.3 to 4.5 % is still more preferable, 0.4 to 4 % is especially preferable. If it is the said range, it may become easy to use for the use which transparency is requested|required. The haze tends to worsen when, for example, the stretching temperature and the heat setting temperature are too high, the cooling roll (CR) temperature is high and the cooling rate of the stretched fabric sheet is slow, and there are too many low molecular weight components, By doing so, it can be made into the above-mentioned range. The haze measurement method will be described later.

0.011 is preferable, as for the minimum of the plane orientation coefficient of the biaxially-oriented laminated polypropylene film of this invention, 0.012 is more preferable, 0.013 is still more preferable. If it is the said range, the heat resistance and rigidity of a film will become large easily.

The stretched laminated polypropylene film generally has a crystal orientation, and the direction and degree have a large influence on the film physical properties. The degree of crystal orientation tends to change depending on the molecular structure of the polypropylene used and the process and conditions in film manufacture, and can be made into said range by adjusting these. The measurement method will be described later.

Evaluation of the ink adhesiveness of the biaxially-oriented polypropylene film of this invention was performed by the number of objects of the part to peel out of all 25 places by performing the peeling test of the printing ink which carried out gravure printing. 15 or less of peeling locations are preferable, 5 or less are more preferable, and 0 is the most preferable. If it is 15 or more, the degree of peeling of the ink increases, which is a problem. The evaluation method of ink adhesiveness is mentioned later.

1.2-2.5 N/15 mm is preferable, as for the lamination strength of the longitudinal direction after lamination with respect to the biaxially-oriented polypropylene film of this invention, 1.3-2.5 N/mm is more preferable, 1.4-2.5 N/mm is further desirable. The measuring method of lamination strength is mentioned later.

It is preferable that it is 0.5 or less, as for the dynamic friction coefficient of the biaxially-oriented polypropylene film of this invention, it is more preferable that it is 0.48 or less, It is especially preferable that it is 0.45 or less. If the coefficient of kinetic friction is 0.5 or less, the film can be smoothly unwound from the roll film, and the printing process is easy. A method of measuring the coefficient of kinetic friction will be described later.

(6) Manufacturing method

The biaxially oriented laminated polypropylene film of the present invention can be obtained by melt-extruding a polypropylene resin with an extruder to form an unstretched sheet, and stretching the unstretched sheet by a predetermined method and heat-treating it.

In the case of the second invention, the polypropylene raw material for the base layer (A) (polypropylene-based resin composition for the base layer (A)) and the polypropylene raw material for the surface layer (B) (polypropylene-based resin composition for the surface layer (B)) Each can be obtained by melt-extruding by a separate extruder to form a laminated unstretched sheet, and then stretching the unstretched sheet by a predetermined method and heat-treating it.

An unstretched sheet|seat is obtained by using several extruder, a feed block, and a multi manifold. As for melt extrusion temperature, about 200-280 degreeC is preferable.

In the second invention, in order to obtain a laminated film having a good appearance without disturbing the layers within this temperature range, the difference in viscosity (MFR difference) between the polypropylene raw material for the base layer (A) and the polypropylene raw material for the surface layer (B) It is preferable to make it 6 g/10 min or less. When the viscosity difference is larger than 6 g/10 min, the layer is likely to be disturbed, resulting in poor appearance. More preferably, it is 5.5 g/10min or less, More preferably, it is 5 g/10min or less.

25-35 degreeC is preferable and, as for the cooling roll surface temperature, 27-33 degreeC is more preferable. Subsequently, the film is stretched 3 to 8 times, preferably 3 to 7 times in the length (MD) direction with a stretching roll at 120 to 165° C., and then 155 to 175° C. in the TD direction, more preferably 160 to 163° C. In 4 to 20 times, preferably 6 to 12 times stretching is performed. Moreover, it heat-setting at 165-176 degreeC, More preferably, 170-176 degreeC, More preferably, it is 172-175 degreeC, and 2 to 10% of relaxation is performed. After performing corona discharge, plasma treatment, flame treatment, etc. to the biaxially-oriented laminated polypropylene film obtained in this way as needed, a film roll can be obtained by winding up with a winder.

The lower limit of the draw ratio of MD becomes like this. Preferably it is 3 times, More preferably, it is 3.5 times. It may become a film thickness nonuniformity as it is less than the above. The upper limit of the draw ratio of MD becomes like this. Preferably it is 8 times, More preferably, it is 7 times. When it exceeds the above, TD extending|stretching performed continuously may become difficult. The minimum of the extending|stretching temperature of MD becomes like this. Preferably it is 120 degreeC, More preferably, it is 125 degreeC, More preferably, it is 130 degreeC. If it is less than the above, a mechanical load may become large, thickness nonuniformity may become large, or the surface roughening of a film may occur. The upper limit of the extending|stretching temperature of MD becomes like this. Preferably it is 160 degreeC, More preferably, it is 155 degreeC, More preferably, it is 150 degreeC. A higher temperature is preferable for lowering the thermal shrinkage rate, but it may adhere to the roll, making it impossible to stretch, or causing surface roughness.

The minimum of the draw ratio of TD becomes like this. Preferably it is 4 times, More preferably, it is 5 times, More preferably, it is 6 times. It may become thickness nonuniformity as it is less than the above. The upper limit of the TD draw ratio is preferably 20 times, more preferably 17 times, still more preferably 15 times, and particularly preferably 12 times. When it exceeds the above, thermal contraction rate may become high, or it may fracture|rupture at the time of extending|stretching. The preheating temperature in TD stretching rapidly raises the film temperature to the vicinity of the stretching temperature, so it is preferably set 5 to 15° C. higher than the stretching temperature. In TD extending|stretching, it carries out at higher temperature than the conventional biaxially-oriented polypropylene film. The lower limit of the stretching temperature of TD is preferably 155°C, more preferably 157°C, still more preferably 158°C, particularly preferably 160°C. If it is less than the above, it may not be sufficiently softened and fractured or the thermal shrinkage rate may increase. The upper limit of the TD stretching temperature is preferably 170°C, more preferably 168°C, still more preferably 163°C. In order to lower the thermal shrinkage rate, a higher temperature is preferable. However, when the temperature exceeds the above, low molecular components are melted and recrystallized to lower the orientation, and surface roughness and film whitening may occur.

The film after stretching is heat-set. Heat setting can be performed at a higher temperature than the conventional biaxially oriented polypropylene film. The lower limit of the heat setting temperature is preferably 165°C, more preferably 166°C. If it is less than the above, thermal contraction rate may become high. Moreover, in order to lower|hang a thermal contraction rate, the process for a long time is required, and productivity may fall. The upper limit of heat setting temperature becomes like this. Preferably it is 176 degreeC, More preferably, it is 175 degreeC. When it exceeds the above, a low molecular component may melt|dissolve and recrystallize, and surface roughness and a film may whiten.

At the time of heat setting, it is preferable to relax (relax). The lower limit of relaxation is preferably 2%, more preferably 3%. If it is less than the above, thermal contraction rate may become high. The upper limit of relaxation is preferably 10%, more preferably 8%. When the above is exceeded, thickness nonuniformity may become large.

In addition, in order to reduce the thermal shrinkage rate, the film manufactured by the above-described process may be once wound into a roll and then annealed offline. The lower limit of the temperature of the offline annealing is preferably 160°C, more preferably 162°C, still more preferably 163°C. When it is less than the above, the effect of annealing may not be acquired. The upper limit of the offline annealing temperature is preferably 175°C, more preferably 174°C, still more preferably 173°C. When the above is exceeded, transparency may fall or thickness nonuniformity may become large.

The lower limit of the offline annealing time is preferably 0.1 minutes, more preferably 0.5 minutes, still more preferably 1 minute. When it is less than the above, the effect of annealing may not be acquired. The upper limit of the offline annealing time is preferably 30 minutes, more preferably 25 minutes, still more preferably 20 minutes. When the above is exceeded, productivity may fall.

Example

Hereinafter, the present invention will be described in more detail by way of Examples, but the following Examples do not limit the present invention, and changes are included in the present invention if implemented without departing from the spirit of the present invention. In addition, the measuring method of the film physical property obtained by the Example and the comparative example is as follows.

1) stereoregularity

The measurement of the mesopentad fraction ([mm mm]%) was performed using ¹³ C-NMR. The mesopentad fraction was calculated according to the method described in "Zambelli et al., Macromolecules, Vol. 6, p. 925 (1973)". ¹³ C-NMR measurement was carried out at 110°C by dissolving 200 mg of the sample in a mixed solution of o-dichlorobenzene and heavy benzene of 8:2 (volume ratio) at 135°C using "AVANCE500" manufactured by BRUKER.

2) Melt flow rate (MFR; g/10 min)

Based on JIS K7210, it measured at the temperature of 230 degreeC, and the load of 2.16 kgf.

The resin was used by measuring the required amount of the pellet (powder) as it is.

After cutting out the required amount of the film, a sample cut into a square having one side of about 5 mm was used.

3) molecular weight and molecular weight distribution

Molecular weight and molecular weight distribution were calculated|required by monodisperse polystyrene standard using gel permeation chromatography (GPC), and were converted into polypropylene value. Measurement conditions, such as the column used by GPC measurement, a solvent, are as follows.

Solvent: 1,2,4-trichlorobenzene

Column: TSKgel GMHHR-H(20)HT×3

Flow: 1.0ml/min

Detector: RI

Measuring temperature: 140℃

The number average molecular weight (Mn), the mass average molecular weight (Mw), and the molecular weight distribution are respectively defined by the following formula by the number of molecules (Ni) of the molecular weight (Mi) at each elution position of the GPC curve obtained through the molecular weight calibration curve.

Number average molecular weight: Mn=Σ(Ni Mi)/ΣNi

Mass average molecular weight: Mw=Σ(Ni·Mi ² )/Σ(Ni·Mi)

Molecular Weight Distribution: Mw/Mn

When the base line is not clear, it is decided to set the base line in the range from the lowest position on the high molecular weight side of the elution peak on the high molecular weight side closest to the elution peak of the standard substance to the lowest position.

4) thickness

The thickness of each of the base layer (A) and the surface layer (B) was measured by cutting a cross section of a biaxially oriented laminated polypropylene film hardened with a modified urethane resin with a microtome and observing it with a differential interference microscope.

5) Heat shrinkage (%)

Based on JIS Z1712, it measured with the following method. In each of the MD direction and the TD direction, the film was cut to a width of 20 mm and a length of 200 mm, suspended in a hot air oven at 150°C, and heated for 5 minutes. The length after heating was measured, and the heat shrinkage rate was calculated as the ratio of the contracted length to the original length.

6) Tensile modulus (Young's modulus (unit: ㎬))

Based on JISK7127, the Young's modulus of the MD direction and TD direction of a film was measured at 23 degreeC.

7) Ring crush (g)

With a digital ring crush tester (manufactured by Tester Sangyo), prepare a film sample size of 12.7 mm × 152 mm, set the spacer of the attachment according to the thickness of the film sample on the sample table, and in each of the MD and TD directions, the film sample is inserted along the circumference. At 23°C, the maximum load when the compression plate was compressed at a descending rate of 12 mm/min. was taken as the measured value of ring crush.

8) Haze (Unit: %)

It measured according to JISK7105.

9) Dynamic friction coefficient

Based on JISK7125, the corona-treated surfaces of the film were overlapped, and it measured at 23 degreeC.

10) refractive index, plane orientation coefficient

In accordance with JIS K7142-1996 5.1 (Method A), it was measured using an Abbe refractometer manufactured by Atago. The refractive indices along the MD and TD directions were Nx and Ny, respectively, and the refractive indices in the thickness direction were Nz. The plane orientation coefficient ((DELTA)P) was calculated|required by (Nx+Ny)/2-Nz.

11) Surface roughness

The surface roughness evaluation of the obtained film was performed using a three-dimensional roughness meter (manufactured by Kosaka Electric Corporation, model number ET-30HK), with a stylus pressure of 20 mg, a measurement length of 1 mm in the X direction, a feed rate of 100 µm/sec, and a feed rate of 100 µm/sec, in the Y direction. At a feed pitch of 2 µm, the number of recorded lines was 99, the height direction magnification was 20000 times, and the cutoff was 80 µm.

The three-dimensional roughness measurement was performed three times, and the arithmetic mean roughness (SRa), the central plane peak height (SRp), and the central plane valley depth (SRv) were evaluated as the average value.

12) Surface resistivity (LogΩ)

According to JIS K6911, the film was aged at 23°C for 24 hours, and then the corona-treated surface of the film was measured.

13) wetting tension (mN/m)

According to JIS K6768:1999, after the film was aged at 23°C and 50% relative humidity for 24 hours, the corona-treated surface of the film was measured in the following procedure.

1) The measurement is performed in a standard laboratory atmosphere (refer to JIS K7100) at a temperature of 23°C and a relative humidity of 50%.

2) Place the test piece on the substrate of the hand coater (4.1), drop a few drops of the test mixture on the test piece, and immediately spread the wire bar.

When the test mixture is spread using a cotton swab or brush, the liquid spreads rapidly over an area of at least 6 cm2. The amount of the liquid is set to such an extent that a thin layer is formed without forming a puddle.

The determination of the wetting tension is performed in the state of the liquid film after 3 seconds by observing the liquid film of the test mixture in a bright place. The thing which maintains the state at the time of application|coating for 3 seconds or more without generating a liquid film tear becomes a wet state. When the wet state is maintained for 3 seconds or longer, it proceeds to a mixed solution having the next high surface tension, and conversely, when the liquid film is torn in 3 seconds or less, it proceeds to a mixed solution having the next low surface tension.

Repeat this operation to select a liquid mixture that can accurately wet the surface of the test piece for 3 seconds.

3) A new cotton swab is used for each test. The brush or wire bar is rinsed with methanol and dried after each use, as the remaining liquid changes composition and surface tension by evaporation.

4) The operation of selecting a mixture that can wet the surface of the test piece for 3 seconds is performed at least 3 times. The surface tension of the mixture thus selected is reported as the wetting tension of the film.

14) Ink adhesion

On the film, using a gravure printing machine (manufactured by Mitani Tekkosho Co., Ltd.), gravure printing on the entire surface (printing ink amount of 2 g/m 2 ) was performed at a speed of 50 m/min. The ink at this time is water-based ink (Dainippon Ink Chemicals Co., Ltd. make: trade name Ecofine 709 bag). Using this print sample, it was evaluated by checkerboard peeling (2 mm square × 25 pieces, a 90° peeling method using Nichireflection Cellophane Tape (registered trademark) 18 mm wide) and judged from practicality (in more detail) Thus, the following rank separation was performed.

checkerboard eye peeling part 0... (double-circle): It is excellent in printing ink adhesiveness.

〃 1 to 5... (circle): Printing ink adhesiveness is favorable.

〃 6 to 15... (triangle|delta): printing ink adhesiveness is inferior.

〃 16 or more… x: There is no printing ink adhesiveness.

15) Laminate strength

The laminate strength was measured by the following procedure.

1) Preparation of laminate film with sealant film

It carried out as follows using the dry lamination machine of a continuous type.

After gravure coating on the corona surface of the biaxially oriented polypropylene film obtained in Examples and Comparative Examples so that the application amount is 3.0 g / m 2 when drying the adhesive, it was guided to a drying zone and dried at 80 ° C. for 5 seconds. Then, it bonded with the sealant film between rolls provided on the downstream side (roll pressure 0.2 MP, roll temperature: 60 degreeC). The obtained laminate film was subjected to an aging treatment at 40°C for 3 days in a wound state.

The adhesive is an ether-based adhesive obtained by mixing 17.9% by mass of a main agent (manufactured by Toyo Morton, TM329), 17.9% by mass of a curing agent (manufactured by Toyo Morton, CAT8B), and 64.2% by mass of ethyl acetate, and the sealant film is Mui manufactured by Toyobo Corporation. An axially oriented polypropylene film (Pylene (registered trademark) CT P1128, thickness 30 µm) was used.

2) Measurement of laminate strength

The laminate film obtained above was cut out into a rectangle (length 200 mm, width 15 mm) having a long side in the longitudinal direction of a biaxially oriented polypropylene film, and using a tensile tester (Tensilon, manufactured by Orientec Co., Ltd.), 23 ° C. The peel strength (N/15 mm) when T-shaped peeling was measured at the tensile speed of 200 mm/min in the environment of The measurement was performed 3 times, and the average value was made into lamination strength.

(Example 1)

What mixed 99 weight% of polypropylene homopolymer PP-1 shown in Table 1 and 1 weight% of antistatic agent (stearyldiethanolamine stearate (Matsumoto Yushi Co., Ltd. KYM-4K)) was used.

Using a 60 mm extruder, the raw material resin is melted at 250° C., co-extruded from a T die into a sheet, cooled and solidified by a cooling roll at 30° C., and then stretched 4.5 times in the longitudinal direction (MD) at 135° C. did. Next, in the tenter, both ends of the film in the width direction are clamped with clips, and after preheating at 175° C., the film is stretched 8.2 times in the width direction (TD) at 160° C., and heated at 170° C. while relaxing 6.7% in the width direction (TD). fixed. The film-forming conditions at this time were made into film-forming conditions a, and were shown in Table 2.

Using a corona treatment machine manufactured by Sophthal Corona and Plasma GmbH on the one side surface side of the obtained biaxially oriented polypropylene film, corona treatment was performed under the condition of applied current value: 0.75 A, and then it was wound with a winder. The thing was made into the biaxially-oriented single-layer polypropylene film of this invention. The physical properties of the obtained film are as shown in Table 3.

(Example 2)

The polypropylene homopolymer PP-1 shown in Table 1 was changed to polypropylene resin PP-2, and using a 60 mm extruder, the mixed raw material was melted at 250 ° C., and co-extruded from a T die into a sheet, 30 ° C. After solidification by cooling with a cooling roll of Next, in the tenter, both ends of the film in the width direction are clamped with clips, and after preheating at 170° C., the film is stretched 8.2 times in the width direction (TD) at 158° C., and heat at 165° C. while relaxing 6.7% in the width direction (TD). Except having fixed it, it carried out similarly to Example 1, and obtained the biaxially-oriented single-layer polypropylene film. The film-forming conditions at this time were made into film-forming conditions b, and were shown in Table 2. The physical properties of the obtained film are as shown in Table 3.

(Example 3)

In the substrate layer (A), 99% by weight of the polypropylene homopolymer PP-1 shown in Table 1 and 1% by weight of an antistatic agent (stearyldiethanolamine stearate (KYM-4K, Matsumoto Yushi Co., Ltd.)) are mixed one was used. In the surface layer (B), 99.7% by weight of the polypropylene homopolymer PP-1 shown in Table 1 and 0.3% by mass of an anti-blocking agent (commercially available silica particles (average particle diameter: 1.3 µm)) were used. .

The mixed raw material used for the base layer (A) is a 60 mm extruder, and the mixed raw material used for the surface layer (B) is a 65 mm extruder, respectively, the raw resin is melted at 250 ° C. and solidified by cooling with a 30°C cooling roll, and then stretched 4.5 times in the 135°C longitudinal direction (MD). Next, in the tenter, both ends of the film in the width direction are clamped with clips, and after preheating at 175° C., the film is stretched 8.2 times in the width direction (TD) at 160° C., and heated at 170° C. while relaxing 6.7% in the width direction (TD). fixed. It formed into a film under the film forming conditions a shown in Table 2, it wound up with a winder, and obtained the biaxially-oriented laminated polypropylene film of this invention in which the base material layer (A) and the surface layer (B) were laminated|stacked one by one. After performing corona treatment on the surface side of the surface layer (B) of the obtained biaxially-oriented polypropylene film on the conditions of applied current value: 0.75 A using the corona treatment machine manufactured by Sophthal Corona and Plasma GmbH, wine What was further wound up was made into the biaxially-oriented single-layer polypropylene film of this invention. The physical properties of the obtained film are as shown in Table 3.

(Example 4)

Except not containing an antistatic agent in the raw material used for a base material layer (A), it carried out similarly to Example 3, and obtained the biaxially-oriented laminated polypropylene film. The physical properties of the obtained film are as shown in Table 3.

(Example 5)

In the base material layer (A), 99 mass % of polypropylene homopolymer PP-1 shown in Table 1 and 1 mass % of antistatic agent (stearyl diethanolamine stearate (Matsumoto Yushi Co., Ltd. KYM-4K)) are mixed one was used. In addition, in the surface layer (B), 48.7 wt% of polypropylene homopolymer PP-6 shown in Table 1, 51 wt% of ethylene copolymerization polypropylene polymer PP-7 shown in Table 1, and commercially available silica as an anti-blocking agent Except having used what mix|blended 0.3 mass % of particle|grains (average particle diameter: 1.3 micrometers), it carried out similarly to Example 3, and obtained the biaxially-oriented laminated polypropylene film.

(Example 6)

Except having set the film thickness to 30 micrometers, it carried out similarly to Example 1, and obtained the biaxially-oriented single-layer polypropylene film. The physical properties of the obtained film are as shown in Table 3.

(Example 7)

Except having set the film thickness to 40 micrometers, it carried out similarly to Example 1, and obtained the biaxially-oriented single-layer polypropylene film. The physical properties of the obtained film are as shown in Table 3.

(Comparative Example 1)

A biaxially oriented single-layer polypropylene film was obtained in the same manner as in Example 1 except that the polypropylene resin PP-1 shown in Table 1 was changed to the polypropylene resin PP-3 shown in Table 1. The physical properties of the obtained film are as showing in Table 4.

(Comparative Example 2)

A biaxially oriented single-layer polypropylene film was formed in the same manner as in Example 1 except that the polypropylene resin PP-1 shown in Table 1 was changed to the polypropylene resin PP-4 shown in Table 1, but at the time of stretching It fractured|ruptured, and a film was not able to be obtained.

(Comparative Example 3)

A biaxially oriented single-layer polypropylene film was obtained in the same manner as in Example 1 except that the polypropylene resin PP-1 shown in Table 1 was changed to the polypropylene resin PP-5 shown in Table 1. The physical properties of the obtained film are as showing in Table 4.

(Comparative Example 4)

The polypropylene resin PP-1 shown in Table 1 was changed to the polypropylene resin PP-6 shown in Table 1, and using a 60 mm extruder, the raw resin was melted at 250 ° C., and co-extruded from the T die into a sheet, , after being solidified by cooling with a cooling roll at 30°C, it was stretched 4.5 times in the longitudinal direction (MD) at 125°C. Next, in the tenter, both ends of the film in the width direction are clamped with clips, and after preheating at 170° C., the film is stretched 8.2 times in the width direction (TD) at 158° C., and heat at 165° C. while relaxing 6.7% in the width direction (TD). Except having fixed it, it carried out similarly to Example 1, and obtained the biaxially-oriented single-layer polypropylene film. The physical properties of the obtained film are as showing in Table 4.

(Comparative Example 5)

The polypropylene resin PP-1 shown in Table 1 was changed to the polypropylene resin PP-8 shown in Table 1, and using a 60 mm extruder, the raw resin was melted at 250 ° C., and co-extruded from the T die into a sheet, , after being solidified by cooling with a cooling roll at 30°C, it was stretched 4.5 times in the longitudinal direction (MD) at 140°C. Next, in the tenter, both ends of the film in the width direction are clamped with clips, and after preheating at 170° C., the film is stretched 8.2 times in the width direction (TD) at 160° C., and heat at 168° C. while relaxing 6.7% in the width direction (TD). Except having fixed it, it carried out similarly to Example 1, and obtained the biaxially-oriented single-layer polypropylene film. The film forming conditions at this time were made into the film forming conditions c, and were shown in Table 2. The physical properties of the obtained film are as showing in Table 4.

(Comparative Example 6)

The polypropylene resin PP-1 shown in Table 1 was changed to the polypropylene resin PP-9 shown in Table 1, and using a 60 mm extruder, the raw resin was melted at 250 ° C., and co-extruded from a T die into a sheet, , after being cooled and solidified with a cooling roll at 30°C, it was stretched 4.5 times in the longitudinal direction (MD) at 135°C. Next, in the tenter, both ends of the film in the width direction are clamped with clips, and after preheating at 170° C., the film is stretched 8.2 times in the width direction (TD) at 160° C., and heat at 168° C. while relaxing 6.7% in the width direction (TD). Except having fixed it, it carried out similarly to Example 1, and obtained the biaxially-oriented single-layer polypropylene film. The film-forming conditions at this time were made into the film-forming conditions d, and were shown in Table 2. The physical properties of the obtained film are as showing in Table 4.

The biaxially-oriented polypropylene films obtained in Examples 1-5 had a small thermal contraction rate and a large Young's modulus. Especially, the laminated|multilayer film obtained in Examples 3-5 became a film with more favorable lamination strength and ink adhesiveness.

On the other hand, the film obtained by the comparative example 1 had the large thermal contraction rate of the width direction (TD). The film obtained in Comparative Example 3 had a large thermal shrinkage rate in the width direction (TD) and a small Young's modulus in the width direction (TD). The film obtained in Comparative Example 4 has a large thermal contraction rate and a small Young's modulus in the width direction (TD) and the longitudinal direction (MD).

The film obtained in Comparative Example 5 had a small Young's modulus in the width direction (TD). The film obtained by the comparative example 6 had the large thermal contraction rate of the width direction (TD).

Since the biaxially-oriented laminated polypropylene film of this invention has higher heat resistance and rigidity, heat distortion wrinkles become smaller and it is hard to fold, it is excellent in workability.

The biaxially oriented polypropylene film of the present invention can be used not only for food packaging used in standing pouches, but also for label applications.

Claims (5)

A biaxially oriented polypropylene film characterized in that the polypropylene resin constituting the film satisfies the following conditions 1) to 4) and the lower limit of the plane orientation coefficient of the film is 0.0125.
1) The lower limit of the mesopentad fraction is 96%.
2) The upper limit of the amount of copolymerization monomers other than propylene is 0.1 mol%.
3) The mass average molecular weight (Mw)/number average molecular weight (Mn) is 3.0 or more and 5.4 or less.
4) Melt flow rate (MFR) measured at 230°C and 2.16 kgf is 6.5 g/10 min or more and 9.0 g/10 min or less. A substrate layer (A) containing a polypropylene-based resin as a main component and a surface layer (B) containing a polypropylene-based resin as a main component on at least one surface of the substrate layer (A), constituting the substrate layer (A) that the polypropylene resin satisfies the conditions of 1) to 4) below;
And the lower limit of the plane orientation coefficient of the film is 0.0125, The biaxially-oriented polypropylene film characterized by the above-mentioned.
1) The lower limit of the mesopentad fraction is 96%.
2) The upper limit of the amount of copolymerization monomers other than propylene is 0.1 mol%.
3) The mass average molecular weight (Mw)/number average molecular weight (Mn) is 3.0 or more and 5.4 or less.
4) The melt flow rate (MFR) measured at 230°C and 2.16 kgf is 6.2 g/10 min or more and 9.0 g/10 min or less. The biaxially-oriented polypropylene film of Claim 1 or 2 whose thermal contraction rate at 150 degreeC in the longitudinal direction and the transverse direction of a film is 8 % or less. The biaxially oriented polypropylene film according to any one of claims 1 to 3, wherein the film has a tensile modulus of elasticity in the longitudinal direction of 2.0 GPa or more, and the tensile modulus of elasticity in the transverse direction of the film is 4.5 GPa or more. The biaxially oriented polypropylene film according to any one of claims 1 to 4, wherein the film has a haze value of 5% or less.