KR102494385B1 - Laminated Polypropylene Film - Google Patents

Abstract

To provide a laminated polypropylene film having gas barrier properties comparable to polypropylene films coated with polyvinylidene chloride and comprising a film using a propylene polymer and a thin film layer containing an inorganic compound as a main component. A laminated polypropylene film comprising a polypropylene film substrate using a polypropylene resin and a thin film layer containing an inorganic compound as a main component, wherein the laminated polypropylene film has a longitudinal thermal shrinkage of 7% or less at 150°C, and oxygen A laminated polypropylene film having a permeability of 150 mL/m ² /day/MPa or less.

Description

Laminated Polypropylene Film

The present invention relates to a laminated polypropylene film comprising a film using a polypropylene resin and a thin film layer containing an inorganic compound as a main component. More specifically, it relates to a laminated polypropylene film that is excellent in gas barrier properties and can be suitably used in various fields requiring dimensional stability at high temperatures and high rigidity.

Conventionally, stretched polypropylene films have been used universally for a wide range of applications, such as packaging for food and various products, electrical insulation, and surface protection films, because of their excellent flexibility and moisture resistance.

However, for food use, oxygen gas barrier properties are often required in films for their preservation, and laminated films in which inorganic compounds are deposited on conventional polypropylene films do not have sufficient oxygen gas barrier properties, such as polyvinylidene chloride and the like. A solution obtained by dissolving a resin having an oxygen gas barrier property of the above and drying it has been used.

However, since there is a process of applying and drying a liquid in which the oxygen gas barrier resin is dissolved, there is a limit to reducing the production cost, and in addition, the thickness of the oxygen gas barrier resin layer must be about 5 μm, so the time of the lamination step is reduced. There was a difficulty in that it was caught or the cost of raw materials increased.

In addition, since the thickness of the film after lamination is large, there was also a problem that printing, sealing, and bagging were difficult to perform.

Therefore, it has been desired that laminated films obtained by depositing a thin film of an inorganic compound on a polypropylene film have excellent oxygen gas barrier properties, but a laminated film obtained by depositing an inorganic compound directly on a polypropylene film has not obtained gas barrier properties (for example, For example, see Patent Documents 1 and 2).

Japanese Unexamined Patent Publication No. 11-105190 Japanese Unexamined Patent Publication No. 2000-355068

The present invention is made against the background of these prior art problems. That is, an object of the present invention is to provide a polypropylene film substrate using a polypropylene resin, which has gas barrier properties comparable to that of a polypropylene film coated with polyvinylidene chloride, and is low in cost and excellent in processability, and an inorganic compound as the main components. It is to provide a laminated polypropylene film having a thin film layer to be.

The present inventors, as a result of intensive studies in order to achieve such an object, have reached the completion of the present invention. That is, the laminated polypropylene film of the present invention is a laminated polypropylene film comprising a polypropylene film base material using a polypropylene resin and a thin film layer containing an inorganic compound as a main component, A laminated polypropylene film characterized by having a thermal shrinkage rate of 7% or less in the direction and an oxygen permeability of 150 mL/m ² /day/MPa or less.

A conventional laminated polypropylene film has a shrinkage rate of 9% or more at 150° C. in the longitudinal direction, and the thermal energy of deposited particles when depositing an inorganic compound on a polypropylene film substrate or the radiant heat from the permeation of the inorganic compound It is presumed that the polypropylene film substrate causes shrinkage, and a change in the gas barrier property of the inorganic compound layer itself is reduced due to the influence thereof.

In this case, it is preferable that the haze of the laminated polypropylene film is 6% or less.

In this case, it is suitable that the heat shrinkage rate of the transverse direction in 150 degreeC of the said laminated polypropylene film is 7 % or less.

In this case, a laminate comprising the above laminated polypropylene film and polyolefin film is suitable.

According to the laminated polypropylene film of the present invention, it can have oxygen gas barrier properties comparable to polypropylene-based films coated with polyvinylidene chloride, and further thinning is possible.

In addition, since the laminated polypropylene film of the present invention can maintain oxygen gas barrier properties at room temperature as well as oxygen gas barrier properties and other physical properties even when exposed to an environment of about 150° C., it is not considered in conventional polypropylene films. Oxygen gas barrier properties that may not have been possible are required, or they can be used even under high-temperature environments, and are preferably applied in a wide range of applications.

For example, by laminating the laminated polypropylene film of the present invention as a substrate layer with a heat seal layer on the surface layer of the substrate layer, it can be used in various packaging forms requiring heat sealability, but the laminated polypropylene film of the present invention or using the same When heat-sealing the laminated film, the heat-sealing temperature can be set high and the heat-sealing strength improves, so it becomes possible to increase the line speed in fabrication processing and the like, and productivity improves. In some cases, it is used as a base material for extruded laminates with high heat load.

Moreover, even when high-temperature treatment such as retort is performed after unloading, deformation of the bag can be suppressed.

1 is a chart for explaining the azimuth dependence and full width at half maximum of the diffraction intensity of 110 planes of an α-crystal in a wide-angle X-ray diffraction pattern of a polypropylene film used for a base material of a laminated polypropylene film.

The present invention relates to a laminated polypropylene film having excellent gas barrier properties, dimensional stability at high temperatures, and mechanical properties.

The laminated polypropylene film of the present invention is a laminated polypropylene film comprising a polypropylene film substrate using a polypropylene-based resin and a thin film layer containing an inorganic compound as a main component, wherein the laminated polypropylene film has a longitudinal direction at 150°C. A laminated polypropylene film characterized by a heat shrinkage rate of 7% or less and an oxygen permeability of 150 mL/m ² /day/MPa or less.

[Inorganic Thin Film Layer]

The inorganic thin film layer used in the present invention contains an inorganic compound as a main component, and the inorganic compound is preferably an inorganic oxide. As an inorganic oxide, it is preferable that it is at least one of aluminum oxide and a silicon oxide, or these composite oxides.

The term "main component" here means that the total amount of aluminum oxide, silicon oxide, and composite oxides of aluminum oxide and silicon oxide is more than 50 mass% with respect to 100 mass% of the components constituting the thin film layer, preferably 70 It is mass % or more, more preferably 90 mass % or more, and most preferably 100 mass % (components other than aluminum oxide and silicon oxide are not contained as components constituting the thin film layer).

Aluminum oxide as used herein includes at least one or more of various aluminum oxides such as AlO, Al ₂ O, and Al ₂ O ₃ , and the content of various aluminum oxides can be adjusted depending on the production conditions of the thin film layer. Silicon oxide includes at least one of various silicon oxides such as SiO, SiO ₂ , and Si ₃ O ₂ , and the content of the various silicon oxides can be adjusted depending on the production conditions of the thin film layer. The composite oxide of aluminum oxide and silicon oxide is made of AlxSiy (x = 1 to 2, y = 1 to 3), and the content of various silicon oxides can be adjusted according to the manufacturing conditions of the thin film layer. Aluminum oxide, silicon oxide, and the composite oxide of aluminum oxide and silicon oxide may contain other components in trace amounts (up to 3% at most with respect to all components) within a range in which properties are not impaired.

Examples of components other than "main components" include compounds such as titanium oxide, magnesium oxide, zirconium oxide, cerium oxide, and zinc oxide, and mixtures thereof.

The thickness of the inorganic thin film layer is not particularly limited, but is preferably 5 to 500 nm, more preferably 10 to 200 nm, still more preferably 15 to 50 nm, from the viewpoint of gas barrier properties and flexibility. If the film thickness of the thin film layer is less than 5 nm, there is a risk that satisfactory gas barrier properties may not be obtained. On the other hand, even if it exceeds 500 nm, the effect of improving the gas barrier properties corresponding thereto is not obtained, and the bending resistance and manufacturing cost points It becomes rather disadvantageous in

[Laminated polypropylene film]

The laminated polypropylene film of the present invention is particularly characterized by physical properties of the laminated film. The laminated polypropylene film of the present invention exhibits the following film properties. In addition, each physical property below is measured and evaluated by the method mentioned later in an Example.

(thermal shrinkage rate)

The laminated polypropylene film of the present invention is a stretched film mainly composed of a polypropylene resin, and it is required that the heat shrinkage rate in the machine direction at 150°C is 7% or less. Here, the vertical direction is the flow direction of the film (sometimes referred to as the longitudinal direction or the long side direction), and the transverse direction is the direction perpendicular to the flow direction of the film (sometimes referred to as the transverse direction or width direction). In conventional laminated polypropylene films, the 150°C thermal shrinkage in the machine direction is 9% or more.

The upper limit of the 150°C thermal shrinkage in the machine direction of the laminated polypropylene film of the present invention is preferably 6%, more preferably 5%, still more preferably 4%. When the upper limit of the 150°C thermal contraction rate in the longitudinal direction is within the above range, the gas barrier properties are better.

When an inorganic compound is deposited on a polypropylene film substrate, the film using the propylene-based polymer causes shrinkage due to the thermal energy of the inorganic compound molecules used in the deposition material or radiant heat from the sensor that receives the inorganic compound, but the inorganic thin film layer When the degree of shrinkage of such a polypropylene film base material at the time of formation is small, it is estimated that it becomes difficult for gas to pass through. As a reason, it can be considered that when shrinkage of the polypropylene film base material occurs during formation of the inorganic thin film layer, the inorganic thin film layer is destroyed due to elevation of the surface of the base material or the like, or it becomes difficult to form a dense inorganic thin film layer.

The lower limit of the 150°C thermal shrinkage in the longitudinal direction is preferably 0.2%, more preferably 0.3%, still more preferably 0.5%, particularly preferably 0.7%, and most preferably 1.0%. The lower limit of the thermal shrinkage rate at 150°C in the machine direction makes realistic production easier in terms of the above range, cost, and the like, or thickness unevenness may be reduced.

The upper limit of the 150°C thermal shrinkage in the transverse direction of the laminated polypropylene film of the present invention is preferably 7%, more preferably 6%, still more preferably 5%, and particularly preferably 4%. If the upper limit of the 150°C heat shrinkage rate in the transverse direction is within the above range, when the laminated polypropylene film or the laminated film using the same is further heat-sealed, the adhesive strength (heat-seal strength) is improved by setting the heat-seal temperature high. , it becomes possible to increase the line speed in bagging processing, etc., and productivity improves. In addition, the amount of deformation of the bag can be suppressed even when performing high-temperature treatment such as retort after unloading.

The lower limit of the 150°C heat shrinkage in the transverse direction is preferably 0.2%, more preferably 0.3%, still more preferably 0.5%, particularly preferably 0.7%, and most preferably 1.0%. The lower limit of the 150°C heat shrinkage rate in the transverse direction may make realistic production easier or reduce thickness unevenness in terms of the above range, cost, and the like.

(Oxygen permeability)

In the present invention, the upper limit of the oxygen permeability of the laminated polypropylene film at a temperature of 23°C and a relative humidity of 65% needs to be 150 mL/m ² /day/MPa or less. More preferably, it is 130 mL/m ² /day/MPa or less, still more preferably 120 mL/m ² /day/MPa or less, still more preferably 100 mL/m ² /day/MPa or less, and particularly preferably is 90 mL/m ² /day/MPa or less. When the upper limit of the oxygen permeability exceeds 150 mL/m ² /day/MPa, the preservability of substances or foods deteriorated by oxygen becomes poor. The lower limit of the oxygen permeability of the laminated polypropylene film at a temperature of 23°C and a humidity of 65% is not particularly limited, but is preferably 0.1 mL/m ² /day/MPa or more. In addition, from a manufacturing viewpoint, it is considered that 0.1 mL/m ² /day/MPa is the lower limit.

(Haze)

The upper limit of the haze of the laminated polypropylene film of the present invention is preferably 6%, more preferably 5%, even more preferably 4.5%, even more preferably 4%, and particularly preferably 3.5%. %am. If the upper limit of the haze is within the above range, it can be easily used for applications requiring transparency. In order to make the haze 6% or less, it is preferable that the inorganic thin film layer is transparent.

The lower limit of the haze of the laminated polypropylene film of the present invention is, as a realistic value, preferably 0.1%, more preferably 0.2%, still more preferably 0.3%, and particularly preferably 0.4%.

[Polypropylene film substrate]

The polypropylene film base material used in the laminated polypropylene film of the present invention is particularly characterized by film properties. The stretched polypropylene film of the present invention exhibits the following film properties. In addition, each physical property below is set as the value measured and evaluated by the method mentioned later in an Example, for example.

(thermal shrinkage rate)

The polypropylene film substrate used in the present invention is a stretched film mainly composed of a polypropylene resin, and the upper limit of the thermal contraction rate in the machine direction at 150°C is preferably 10%, more preferably 9%. , more preferably 7%, particularly preferably 5%. In conventional polypropylene films, the 150°C thermal shrinkage in the machine direction is 11% or more. By setting the thermal contraction rate of the polypropylene film substrate to 10% or less, the thermal shrinkage rate in the machine direction at 150°C of the laminated polypropylene film of the present invention can be 7% or less.

In addition, the polypropylene film base material used in the present invention is a stretched film mainly composed of a polypropylene resin, and preferably has a heat shrinkage rate in the transverse direction at 150 ° C. of 15% or less, more preferably 9%, More preferably, it is 7%, and particularly preferably, it is 7%. In conventional polypropylene films, the 150°C heat shrinkage in the transverse direction is 16% or more. By setting the thermal contraction rate of the polypropylene film substrate to 10% or less, the thermal shrinkage rate in the transverse direction at 150°C of the laminated polypropylene film of the present invention can be 7% or less.

Here, the vertical direction is the flow direction of the film (sometimes referred to as the longitudinal direction), and the transverse direction is the direction perpendicular to the flow direction of the film (sometimes referred to as the width direction).

The lower limit of the 150°C heat shrinkage of the polypropylene film base material used in the machine direction and transverse direction is preferably 0.2%, more preferably 0.3%, still more preferably 0.5%, particularly preferably. is 0.7%, most preferably 1.0%. In terms of the 150°C thermal shrinkage rate, in terms of the above range, cost, etc., realistic production may be facilitated, or thickness unevenness may be reduced.

In addition, if the 150°C heat shrinkage rate is up to about 1.5%, it is possible by adjusting the stretching conditions and heat setting conditions of the film to increase the low molecular weight component of polypropylene in the film substrate, for example, but in order to drop it to 1.5% or less , it is preferable to perform the annealing treatment offline.

(Haze)

The lower limit of the haze of the polypropylene film base material used in the present invention is, as a practical value, preferably 0.1%, more preferably 0.2%, still more preferably 0.3%, and particularly preferably 0.4%. The upper limit of the haze is preferably 6%, more preferably 5%, still more preferably 4.5%, particularly preferably 4%, and most preferably 3.5%. When the haze is within the above range, it can be easily used for applications requiring transparency. Haze tends to deteriorate, for example, when the stretching temperature and heat setting temperature are too high, when the cooling roll (CR) temperature is high and the cooling rate of the stretched raw sheet is slow, and when the low molecular weight is too high, and these are adjusted By doing so, it can be controlled within the above range.

(thickness)

The lower limit of the thickness of the polypropylene film substrate used in the present invention is 3 μm, preferably 4 μm, and more preferably 8 μm.

When the lower limit of the thickness of the film is less than 3 μm, the laminated polypropylene film tends to curl, and the gas barrier property tends to decrease.

From the viewpoint of workability of the film thickness, the upper limit is preferably 300 μm, more preferably 250 μm, even more preferably 200 μm, even more preferably 150 μm, particularly preferably 100 μm, and the most Preferably it is 50 micrometers.

(impact resistance)

The lower limit of the impact resistance (23°C) of the polypropylene film substrate used in the present invention is preferably 0.6 J, more preferably 0.7 J. When the impact resistance is within the above range, the film has sufficient toughness and is not broken during handling. From a practical point of view, the upper limit of the impact resistance is preferably 2J, more preferably 1.8J, even more preferably 1.6J, and particularly preferably 1.5J. For example, when the low molecular weight component of the polypropylene in the film substrate is large, when the overall molecular weight is low, when the high molecular weight component of the polypropylene in the film substrate is small, and when the molecular weight of the high molecular weight component is low, the impact resistance is improved. Since it tends to decrease, impact resistance can be controlled within the above range by adjusting these factors according to the application.

(Young's modulus)

When the polypropylene film substrate used in the present invention is a biaxially stretched film, the lower limit of the Young's modulus in the machine direction (23°C) is preferably 2 GPa, more preferably 2.1 GPa, still more preferably 2.2 GPa. , particularly preferably 2.3 GPa, most preferably 2.4 GPa. The upper limit of the Young's modulus in the machine direction is preferably 4 GPa, more preferably 3.7 GPa, still more preferably 3.5 GPa, particularly preferably 3.4 GPa, and most preferably 3.3 GPa. When the Young's modulus in the longitudinal direction is within the above range, realistic production is easy and the vertical-horizontal balance is good in some cases.

When the polypropylene film used for the substrate of the present invention is a biaxially stretched film, the lower limit of the Young's modulus in the transverse direction (23°C) is preferably 3.8 GPa, more preferably 4 GPa, still more preferably 4.1 GPa. , and is particularly preferably 4.2 GPa. The upper limit of the Young's modulus in the transverse direction is preferably 8 GPa, more preferably 7.5 GPa, still more preferably 7 GPa, and particularly preferably 6.5 GPa. When the Young's modulus in the transverse direction is within the above range, realistic production is easy, and the Young's modulus balance between the longitudinal and lateral directions may be good in some cases. Note that the Young's modulus in the machine direction and the transverse direction can be increased, for example, by increasing the draw ratio in each direction. In addition, when transverse stretching is performed after stretching in the machine direction, the longitudinal stretch ratio is set slightly lower and the transverse stretch is performed. The Young's modulus in the lateral direction can be increased by setting the magnification to a high level or the like.

(thickness uniformity)

The lower limit of the thickness uniformity of the polypropylene film substrate used in the present invention is preferably 0%, more preferably 0.1%, still more preferably 0.5%, and particularly preferably 1%. The upper limit of the thickness uniformity is preferably 20%, more preferably 17%, still more preferably 15%, particularly preferably 12%, and most preferably 10%. If the uniformity of the thickness is within the above range, it is difficult to cause defects during subsequent processing such as coating or printing, and it is easy to use for applications requiring precision.

(film density)

The lower limit of the density of the polypropylene film substrate used in the present invention is preferably 0.910 g/cm ³ , more preferably 0.911 g/cm ³ , still more preferably 0.912 g/cm ³ , and particularly preferably is 0.913 g/cm ³ . When the film density is within the above range, the crystallinity is high and the thermal shrinkage rate may be small. The upper limit of the film density is preferably 0.930 g/cm ³ , more preferably 0.928 g/cm ³ , still more preferably 0.926 g/cm ³ , and particularly preferably 0.925 g/cm ³ . When the film density exceeds the above upper limit, production may become difficult in reality. The film density can be increased by increasing the stretching ratio or the stretching temperature, increasing the heat setting temperature, and further annealing off-line.

(refractive index)

The lower limit of the refractive index (Nx) in the machine direction of the polypropylene film substrate used in the present invention is preferably 1.502, more preferably 1.503, still more preferably 1.504. The upper limit of Nx is preferably 1.520, more preferably 1.517, still more preferably 1.515.

The lower limit of the transverse refractive index (Ny) of the polypropylene film substrate used in the present invention is preferably 1.523, more preferably 1.525. The upper limit of Ny is preferably 1.535, more preferably 1.532.

The lower limit of the refractive index (Nz) in the thickness direction of the polypropylene film substrate used in the present invention is preferably 1.480, more preferably 1.489, still more preferably 1.500. The upper limit of Nz is preferably 1.510, more preferably 1.507, still more preferably 1.505.

(plane orientation factor)

The lower limit of the plane orientation coefficient of the polypropylene film used for the substrate of the present invention is preferably 0.0125, more preferably 0.0126, still more preferably 0.0127, and particularly preferably 0.0128. The upper limit of the plane orientation coefficient is, as a practical value, preferably 0.0155, more preferably 0.0150, still more preferably 0.0148, and particularly preferably 0.0145. The plane orientation coefficient can be within a range by adjusting the draw ratio. When the plane orientation coefficient is within this range, the thickness nonuniformity of the film also tends to be good.

(orientation of film)

A polypropylene film substrate generally has a crystal orientation, and the direction or extent thereof has a great influence on the physical properties of the film. The degree of crystal orientation changes depending on the molecular structure of the polypropylene used and the process and conditions in film production. In addition, the orientation direction of the stretched polypropylene film can be determined by a wide-angle X-ray diffraction method by injecting X-rays perpendicularly to the film surface and measuring the azimuthal dependence of the crystal-derived scattering peak. In detail, the stretched polypropylene film typically has a monoclinic α-type crystal structure. When the azimuthal dependence of the scattering intensity of 110 planes (plane spacing: 6.65 angstroms) is measured by the wide-angle X-ray diffraction method, the α-type crystal has a strong orientation mainly in one axis. That is, when the scattering intensity derived from plane 110 of the α-type crystal is plotted against the azimuth angle, the strongest peak is observed in the direction perpendicular to the orientation of the molecular axes. In the present invention, the degree of orientation is defined by the half-value width of this maximum peak.

Fig. 1 shows a typical pattern of the azimuthal dependence of scattering originating from the 110 plane of the α-type crystal of polypropylene. Further, in Fig. 1, half-value widths of the main peaks (maximum peaks, azimuth angles of 180° and 360°) of the azimuthal angle dependence of 110 planes are shown.

In the polypropylene film used for the substrate of the present invention, it is preferable that the half width of the maximum peak when the scattering intensity of 110 planes measured by the wide-angle X-ray scattering method is plotted against the azimuth angle is 30 degrees or less. The upper limit of this half value width is more preferably 29 degrees, still more preferably 28 degrees. When the half-value width of the azimuthal dependence of the scattering intensity derived from the 110 plane is larger than the above range, the orientation is not sufficient, and the heat resistance and rigidity are not sufficient. The lower limit of the half-value width of the azimuthal angle dependence of the scattering intensity derived from 110 planes is preferably 5 degrees, more preferably 7 degrees, still more preferably 8 degrees. When the half-value width of 110 planes is smaller than the above range, a decrease in impact resistance or orientation cracking may occur.

(Wide-angle X-ray diffractometer)

The half-value width specified above is preferably measured using X-rays with high parallelism, and synchrotron radiation is preferably used.

The X-ray generation source used in the wide-angle X-ray diffraction measurement may be a general apparatus such as a tube type or rotary type used in a laboratory, but it is preferable to use a high-luminance light source capable of irradiating high-intensity radiation with high parallelism. In synchrotron radiation, since X-rays are difficult to spread and the luminance is high, measurement can be performed with high accuracy and in a short time. Since high-precision measurement is possible, detailed crystal orientation evaluation is possible. On the other hand, with X-rays with low luminance, when measuring a film sample with a thickness of several tens of micrometers, it takes a long time to measure unless multiple sheets are overlapped. The peak when the scattering intensity is plotted with respect to the azimuth angle tends to become broad, and the value of the obtained full width at half maximum tends to increase.

Examples of facilities capable of irradiating high-intensity synchrotron radiation with high parallelism include large synchrotron radiation facilities such as SPring-8. It is preferred to measure the full width at half maximum of the present invention.

(Long period structure, small angle X-ray scattering (SAXS))

In the polypropylene film substrate used in the present invention, it is preferable that the long period size is large. In general, crystalline polymers have a regular layered structure (periodic structure) including repetitions of crystals and amorphous. Here, the size of a repeating unit including crystals and non-crystals is referred to as a long period size. The long period size can be obtained from the scattering peak angle derived from the long period structure in the main orientation direction measured by the small-angle X-ray scattering method.

As for the long-period scattering peak of the polypropylene film used for the substrate of the present invention by small-angle X-ray scattering measurement, it is preferable that the peak is clearly observed in the main orientation direction. Here, the main orientation direction indicates a direction in which scattering due to a long period of a polymer crystal is seen more strongly in a two-dimensional X-ray scattering pattern. In the case of uniaxial stretching, the main orientation direction coincides with the stretching direction in many cases, and in the case of sequential biaxial stretching of longitudinal stretching and transverse stretching, the main orientation direction is the transverse stretching direction, although it varies depending on the respective stretching ratio. This often coincides with The clearer the long-period peak resulting from the polymer crystal is observed, the more highly ordered the long-period structure is formed.

In the polypropylene film used for the substrate of the present invention, it is preferable that the long period size obtained from the long period scattering peak is 40 nm or more. The lower limit of the long period size is more preferably 41 nm, and even more preferably 43 nm. When the long period size is smaller than the above range, the melting peak temperature tends to be low, and thus the heat resistance tends to decrease. The upper limit of the long period size is preferably 100 nm, more preferably 90 nm, still more preferably 80 nm. When the long period size is larger than the above range, practical production tends to be difficult because crystallization or heat treatment takes a long time.

(Small-angle X-ray diffractometer)

The X-ray source used in the small-angle X-ray scattering measurement is not particularly limited, and a general device such as a tube type or rotary type used in a laboratory can be used. , it is preferable to use a high-brightness light source capable of irradiating high-brightness radiation. In particular, when the polypropylene film base material used in the present invention has a large long period, X-ray scattering derived from the long period structure is more in the small angle area. Therefore, it is difficult to measure with an X-ray apparatus in a laboratory with a large X-ray beam diameter and a short camera length, so that X-rays are difficult to spread, the beam diameter can be narrowed to a few hundred micrometers or less, and the luminance is high. It is preferable to measure the ultra-small angle area based on a long camera length using . At this time, the length of the camera is preferably 7 m or more.

[Polypropylene resin]

The polypropylene resin used in the polypropylene film substrate of the present invention is not particularly limited, and for example, a homopolymer of propylene, a copolymer of ethylene and/or an α-olefin having 4 or more carbon atoms, or a mixture thereof can be used. there is.

As the polypropylene resin constituting the film, a propylene homopolymer substantially free of a comonomer is preferable, and even when a comonomer is included, the amount of the comonomer is preferably 0.5 mol% or less. The upper limit of the amount of comonomer is preferably 0.3 mol%, more preferably 0.1 mol%. Within the above range, crystallinity may be improved and thermal shrinkage at high temperatures may be reduced. In addition, a comonomer may be contained as long as it is in a trace amount within the range which does not significantly reduce crystallinity.

It is more preferable that the polypropylene resin constituting the film is a propylene homopolymer obtained only from propylene monomers, and even if it is a propylene homopolymer, it is most preferable that it does not contain a heterogeneous bond such as a head-head bond.

(Stereoregularity of polypropylene resin)

The lower limit of the mesopentad fraction measured by 13 C-NMR, which is a stereoregular index of the polypropylene resin constituting the film, is preferably 96%. The lower limit of the mesopentad fraction is preferably 96.5%, more preferably 97%. In the above range, crystallinity may be improved and thermal shrinkage at high temperatures may be lowered. The upper limit of the mesopentad fraction is preferably 99.8%, more preferably 99.6%, still more preferably 99.5%. In the above range, practical manufacturing may be facilitated.

The lower limit of the meso-average chain length of the polypropylene resin constituting the film is preferably 100, more preferably 120, still more preferably 130. In the above range, crystallinity may be improved and thermal shrinkage at high temperatures may be reduced. The upper limit of the meso average chain length is preferably 5000 from a practical point of view.

The lower limit of the xylene-soluble content of the polypropylene resin constituting the film is preferably 0.1% by mass from a realistic point of view. The upper limit of the xylene soluble content is preferably 7% by mass, more preferably 6% by mass, still more preferably 5% by mass. In the above range, crystallinity may be improved and thermal shrinkage at high temperatures may be reduced.

(Melt flow rate of polypropylene resin)

The lower limit of the melt flow rate (MFR) (230°C, 2.16 kgf) of the polypropylene resin is 0.5 g/10 min. The lower limit of the MFR is preferably 1.0 g/10 min, more preferably 1.3 g/10 min, still more preferably 1.5 g/10 min, still more preferably 2.0 g/10 min, and particularly preferably 4.0 g. /10 min, preferably 6.0 g/10 min. In the above range, the mechanical load is small, and extrusion or stretching may be facilitated. The upper limit of MFR is 20 g/10 min, preferably 17 g/10 min, more preferably 16 g/10 min, still more preferably 15 g/10 min. In the above range, the thermal contraction rate may be lowered because the stretching becomes easier, the thickness unevenness decreases, or the stretching temperature or the heat setting temperature is easily increased.

(Molecular weight of polypropylene resin)

The lower limit of the number average molecular weight (Mn) measured by gel permeation chromatography (GPC) of the polypropylene resin constituting the film is preferably 20000, more preferably 22000, still more preferably 24000, Especially preferably, it is 26000, and it is 27000 most preferably. In the above range, advantages such as easy stretching, small thickness non-uniformity, high stretching temperature or heat setting temperature, and low thermal shrinkage can be produced. The upper limit of Mn is preferably 200000, more preferably 170000, still more preferably 160000, and particularly preferably 150000. In the above range, the effect of the present application, such as low thermal shrinkage at high temperature of the polypropylene film base material, which is the effect of the low molecular weight material of the polypropylene resin, may be easily obtained, or stretching may be facilitated.

The lower limit of the mass average molecular weight (Mw) measured by GPC of the polypropylene resin constituting the film is preferably 180000, more preferably 200000, still more preferably 230000, still more preferably 240000 , particularly preferably 250000, most preferably 270000. In the above range, advantages such as easy stretching, small thickness non-uniformity, high stretching temperature or heat setting temperature, and low thermal shrinkage can be produced. The upper limit of Mw is preferably 500000, more preferably 450000, still more preferably 420000, particularly preferably 410000, and most preferably 400000. In the above range, the mechanical load is small, and extrusion or stretching may be facilitated.

(Molecular weight distribution of polypropylene resin)

The polypropylene resin used in the present invention preferably has the following characteristics. That is, when the gel permeation chromatography (GPC) integration curve of the polypropylene resin constituting the film 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 38% by mass. %, more preferably 40% by mass, particularly preferably 41% by mass, and most preferably 42% by mass. In the above range, the effect of the present application, such as a low thermal shrinkage at high temperature, which is an effect of a low molecular weight material, may be easily obtained, or stretching may be facilitated. The upper limit of the amount of the component having a molecular weight of 100,000 or less in the GPC integration curve is preferably 65% by mass, more preferably 60% by mass, still more preferably 58% by mass, and particularly preferably 56% by mass. , most preferably 55% by mass. In the above range, stretching may be facilitated, thickness non-uniformity may be reduced, or stretching temperature or heat setting temperature may be easily increased, and thus thermal shrinkage may be reduced.

The lower limit of the mass average molecular weight (Mw)/number average molecular weight (Mn) of the polypropylene resin used in the present invention, which is an index of the breadth of the molecular weight distribution, is preferably 4, more preferably 4.5, and still more preferably It is preferably 5, particularly preferably 5.5, and most preferably 6. The upper limit of Mw/Mn is preferably 30, more preferably 25, still more preferably 22, particularly preferably 21, and most preferably 20. When Mw/Mn is within the above range, realistic production is easy.

In addition, the molecular weight distribution of polypropylene can be determined by polymerizing components of different molecular weights in multiple stages in a series of plants, by blending components of different molecular weights offline with a kneader, or by blending and polymerizing catalysts having different performances, or by obtaining a desired molecular weight distribution. It is possible to adjust by using or using a catalyst that can be realized.

(Method for producing polypropylene resin)

The polypropylene resin is obtained by polymerizing propylene as a raw material using a known catalyst such as a Ziegler-Natta catalyst or a metallocene catalyst. In particular, in order to eliminate heterogeneous bonds, it is preferable to use a catalyst capable of polymerization with high stereoregularity among Ziegler-Natta catalysts.

As the polymerization method of propylene, a known method may be employed, for example, polymerization in an inert solvent such as hexane, heptane, toluene, xylene, or the like, polymerization in a liquid monomer, addition of a catalyst to a gaseous monomer, A method of polymerization in a gaseous state or a method of polymerization in combination thereof, and the like are exemplified.

(additive)

An additive or other resin may be added to the polypropylene film base material used in the present invention, if necessary. Examples of additives include antioxidants, ultraviolet absorbers, antistatic agents, lubricants, nucleating agents, adhesives, antifogging agents, flame retardants, antiblocking agents, inorganic or organic fillers, and the like. Examples of other resins include polypropylene resins other than the polypropylene resins used in the present invention, random copolymers that are copolymers of propylene and ethylene and/or C4 or more α-olefin, and various elastomers. These are sequentially polymerized using a multi-stage reactor, blended with a polypropylene resin with a Henschel mixer, diluted with polypropylene to a predetermined concentration of master pellets prepared in advance using a melt kneader, or melted in advance You can use it by kneading it.

(Method for producing stretched polypropylene film)

The polypropylene film used for the base material of the present invention may be a uniaxially stretched film in the longitudinal direction (longitudinal direction) or in the transverse direction (widthwise direction), but is preferably a biaxially stretched film. In the case of biaxial stretching, sequential biaxial stretching or simultaneous biaxial stretching may be employed.

Hereinafter, a method for producing a sequential biaxially stretched film of longitudinal stretching and transverse stretching, which is the most preferable example, will be described.

First, a polypropylene-based resin is heated and melted with a single-screw or twin-screw extruder and extruded onto a cooling roll to obtain an unstretched sheet. As the melt extrusion conditions, the resin temperature is set to 200 to 280°C, the resin is extruded into a sheet shape by a T die, and solidified by cooling with a cooling roll at a temperature of 10 to 100°C. Subsequently, the film is stretched 3 to 8 times, preferably 3 to 7 times in the longitudinal (longitudinal) direction with a stretching roll at 120 to 165°C, and then stretched at 155°C to 175°C, preferably 158°C to 175°C in the transverse direction. Stretching is performed at a temperature of 170 DEG C by 4 to 20 times, preferably 6 to 12 times. Additionally, heat treatment is performed at an ambient temperature of 165 to 175°C, preferably 166 to 173°C, allowing a relaxation of 1 to 15%. A roll sample can be obtained by winding up with a winder, after giving corona discharge treatment to the polypropylene film obtained in this way on at least one side|surface as needed.

The lower limit of the stretching ratio in the machine direction is preferably 3 times, more preferably 3.5 times. If the stretching ratio in the machine direction is less than the above, the film thickness may be uneven. The upper limit of the stretching ratio in the machine direction is preferably 8 times, more preferably 7 times. When the stretching ratio in the machine direction exceeds the above, subsequent transverse stretching may become difficult.

The lower limit of the stretching temperature in the machine direction is preferably 120°C, more preferably 125°C, still more preferably 130°C. If the stretching temperature in the machine direction is lower than the above, mechanical load may increase, thickness unevenness may increase, or surface roughness of the film may occur. The upper limit of the stretching temperature in the machine direction is preferably 165°C, more preferably 160°C, even more preferably 155°C, and particularly preferably 150°C. A higher stretching temperature is preferable for lowering the thermal shrinkage, but it may adhere to the roll, making it impossible to stretch, or surface roughness may occur.

The lower limit of the horizontal stretch ratio is preferably 4 times, more preferably 5 times, still more preferably 6 times. If the transverse draw ratio is less than the above, thickness nonuniformity may occur. The upper limit of the transverse stretch ratio is preferably 20 times, more preferably 17 times, still more preferably 15 times, and particularly preferably 12 times. If the horizontal stretch ratio exceeds the above, the heat shrinkage rate may increase or breakage may occur during stretching.

The preheating temperature in transverse stretching is preferably set 5 to 15° C. higher than the stretching temperature in order to quickly raise the film temperature to around the stretching temperature.

Horizontal stretching is preferably performed at a temperature 3 to 5°C higher than that of conventional stretched polypropylene films. The lower limit of the TD stretching temperature is preferably 155°C, more preferably 157°C, still more preferably 158°C. If the transverse stretching temperature is lower than the above, it may not be sufficiently softened and broken, or the thermal shrinkage rate may be increased. The upper limit of the transverse stretching temperature is preferably 175°C, more preferably 170°C, still more preferably 168°C. In order to lower the thermal shrinkage rate, the transverse stretching temperature is preferably higher, but if it exceeds the above, the low molecular weight component melts and recrystallizes, not only the orientation decreases, but also the surface roughness and whitening of the film may occur.

The film after extending|stretching is usually heat-set. In the present invention, it is possible to perform heat setting at a temperature 3 to 10° C. higher than that of conventional oriented polypropylene films. The lower limit of the heat setting temperature is preferably 165°C, more preferably 166°C. If the heat setting temperature is less than the above, the heat shrinkage rate may be increased. In addition, long-term processing is required to lower the thermal shrinkage rate, which may lower productivity. The upper limit of the heat setting temperature is preferably 175°C, more preferably 173°C. If the heat setting temperature exceeds the above, the low molecular weight component may melt and recrystallize, resulting in whitening of the surface roughness or film.

It is preferable to relax (relieve) at the time of heat setting. The lower limit of relaxation is preferably 1%, more preferably 2%, still more preferably 3%. In a relaxation less than the above, the thermal contraction rate may increase. The upper limit of relaxation is preferably 10%, more preferably 8%. In relaxation exceeding the above, thickness nonuniformity may increase.

In addition, in order to reduce the thermal shrinkage rate, the film manufactured in the above process may be once wound up in a roll shape and then annealed off-line. The lower limit of the off-line annealing temperature is preferably 160°C, more preferably 162°C, still more preferably 163°C. If the off-line annealing temperature is less than the above, the effect of annealing may not be obtained. The upper limit of the off-line annealing temperature is preferably 175°C, more preferably 174°C, still more preferably 173°C. When the off-line annealing temperature exceeds the above, transparency may decrease or thickness unevenness may increase.

The lower limit of the off-line annealing time is preferably 0.1 minute, more preferably 0.5 minute, still more preferably 1 minute. If the offline annealing time is less than the above, the effect of annealing may not be obtained. The upper limit of the offline annealing time is preferably 30 minutes, more preferably 25 minutes, still more preferably 20 minutes. If the off-line annealing time exceeds the above, productivity may decrease.

In addition, if the 150 ° C. thermal shrinkage rate is up to about 1.5%, it is possible, for example, by adjusting the stretching conditions or heat setting conditions to increase the low molecular weight component, but in order to lower it to 1.5% or less, annealing treatment off-line is required. it is desirable

Haze tends to deteriorate, for example, when the stretching temperature and the heat setting temperature are too high, when the cooling roll (CR) temperature is high and the cooling rate of the stretched raw sheet is slow, and when the low molecular weight is too high, adjusting these By doing so, it can be controlled within the above range.

The stretched polypropylene film obtained in this way is usually formed into a film with a width of about 2000 to 12000 mm and a length of about 1000 to 50000 m, and is wound into a roll shape. In addition, it is slit according to each application and provided as a slit roll with a width of 300 to 2000 mm and a length of about 500 to 5000 m.

(Method of manufacturing inorganic thin film layer)

For production of the inorganic thin film layer, well-known manufacturing methods such as PVD methods (physical vapor deposition) such as vacuum deposition, sputtering, and ion plating, or CVD (chemical vapor deposition) are appropriately used, but physical vapor deposition is preferred. Vacuum deposition method is more preferable. For example, in the vacuum deposition method, a mixture of Al ₂ O 3 and SiO ₂ or a mixture of Al and SiO ₂ is used as a deposition source material, and resistance heating, high frequency induction heating, electron beam heating, etc. can be used as a heating method. there is. In addition, oxygen, nitrogen, water vapor, etc. may be introduced as a reactive gas, or reactive deposition using means such as ozone addition or ion assist may be used. In addition, the production conditions may be changed as long as the object of the present invention is not impaired, such as adding a bias or the like to the film substrate or raising or lowering the temperature of the film substrate. The same applies to other manufacturing methods such as the spatter method and the CVD method.

At this time, a coating layer may be provided between the polypropylene film substrate and the inorganic thin film layer, or a coating layer may be provided on the inorganic thin film layer.

[Usage]

The laminated polypropylene film of the present invention has the above excellent properties not found in the prior art. When used as a packaging film, not only can it be used as an alternative to polypropylene film coated with polyvinylidene chloride because of its excellent gas barrier properties, but also it can be reduced in thickness because it has higher rigidity than that, and further cost reduction and weight reduction are possible. do.

In addition, since the laminated polypropylene film of the present invention has high heat resistance, processing at high temperatures during coating or printing is possible, and production efficiency can be improved or coating agents, inks, laminate adhesives, etc. that have been difficult to use in the past can be used.

Further, the laminated polypropylene film of the present invention is not limited to packaging, and can also be used as an insulating film for capacitors and motors, and a base film for solar cell back sheets.

(Manufacturing method of laminated body)

Food and beverages, pharmaceuticals, detergents, shampoos, oils, toothpaste, adhesives, adhesives, cosmetics, and other various articles A packaging container having excellent filling and packaging aptitude, storage aptitude, and the like can be manufactured.

As the polyolefin-based resin layer having heat-sealing properties, a film or sheet of a resin that can be melted by heat and fused to each other can be used. Specifically, for example, low-density polyethylene, medium-density polyethylene, high-density polyethylene, linear (linear) ) Low-density polyethylene, polypropylene, ethylene-vinyl acetate copolymer, ionomer-resin, ethylene-acrylic acid copolymer, ethylene-ethyl acrylate copolymer, ethylene-methacrylic acid copolymer, ethylene-methyl methacrylate copolymer, ethylene -Acids modified by unsaturated carboxylic acids such as acrylic acid, methacrylic acid, maleic acid, maleic anhydride, fumaric acid, itaconic acid, etc. from polyolefinic resins such as propylene copolymer, methylpentene polymer, polybutene polymer, polyethylene or polypropylene Modified polyolefin resins, polyvinyl acetate-based resins, poly(meth)acrylic-based resins, polyvinyl chloride-based resins, and various other resin films or sheets can be used. A typical example is a film or sheet made of linear (linear) low-density polyethylene or polypropylene.

The upper limit of the oxygen permeability of the laminated body at a temperature of 23°C and a relative humidity of 65% is preferably 50 mL/m ² /day/MPa, more preferably 30 mL/m ² /day/MPa, still more preferably It is 20 mL/m ² /day/MPa, and particularly preferably 15 mL/m ² /day/MPa. When the upper limit of the oxygen permeability is 50 mL/m ² /day/MPa, the preservability of substances and foods deteriorated by oxygen is excellent. The lower limit of the oxygen permeability of the laminated polypropylene film at a temperature of 23°C and a humidity of 65% is not particularly limited, but is preferably 0.1 mL/m ² /day/MPa. In addition, from a manufacturing viewpoint, it is considered that 0.1 mL/m ² /day/MPa is the lower limit.

The lower limit of the laminate strength in the longitudinal direction of the laminated body is preferably 1.1 N/15 mm, more preferably 1.2 N/15 mm, still more preferably 1.2 N/15 mm. When the lower limit of the laminate strength in the longitudinal direction is 1.1 N/15 mm, the strength of the packaging container is excellent. The upper limit of the laminate strength in the longitudinal direction is not particularly limited, but is preferably 3.0 N/15 mm. Moreover, it is considered that 3.0 N/15 mm is an upper limit from a manufacturing viewpoint.

[Example]

The present invention will be described in detail below based on examples, but the present invention is not limited to these examples. The method for measuring physical properties in Examples is as follows.

1) Stereoregularity

The mesopentad fraction ([mmmm]%) and meso average chain length were measured using 13 C-NMR as follows.

The mesopentad fraction was calculated according to the method described in "Zambelli et al., Macromolecules, Vol. 6, p. 925 (1973)".

The meso average chain length is found in “J.C. It was calculated according to the method described in “Polymer Sequence Distribution” by Randall, Chapter 2 (1977) (Academic Press, New York).

13 C-NMR measurement was performed at 110°C after dissolving 200 mg of the sample in an 8:2 (volume ratio) mixture of o-dichlorobenzene and heavy benzene at 135°C using "AVANCE500" manufactured by BRUKER.

2) Xylene soluble content (unit: mass %)

After dissolving 1 g of polypropylene sample in 200 mL of boiling xylene, allowing it to cool, recrystallizing it in a constant temperature water bath at 20 ° C. for 1 hour. It was called.

3) Melt flow rate (MFR, unit: g/10 min)

MFR was measured at a temperature of 230°C and a load of 2.16 kgf in accordance with JIS K7210-1:2014.

4) molecular weight and molecular weight distribution

Molecular weight and molecular weight distribution were determined by monodisperse polystyrene standards using gel permeation chromatography (GPC). The measurement conditions, such as the column used in a GPC measurement and a solvent, are as follows.

Solvent: 1,2,4-trichlorobenzene

Column: TSKgel GMHHR-H(20)HT×3

Flow: 1.0ml/min

Detector: RI

Measurement temperature: 140℃

The number average molecular weight (Mn), mass average molecular weight (Mw), and Z+1 average molecular weight (Mz+1) are the number of molecules (Ni) of the molecular weight (Mi) at each elution position in the GPC curve obtained through the molecular weight calibration curve, respectively. is defined by the following formula:

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

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

Z+1 average molecular weight: Mz+1=Σ(Ni·Mi ⁴ )/Σ(Ni·Mi ³ )

Molecular Weight Distribution: Mw/Mn

In addition, the molecular weight of the peak position of the GPC curve was set to Mp.

When the base line was not clear, it was decided to set the base line in the range from the lowest position of the region 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.

5) Wide-angle X-ray diffraction

In the embodiment of the present invention, in the second hatch of the beam line BL03XU owned by the Frontier Soft Matter Development Industry-University Alliance (FSBL) in the large-scale radiation facility SPring-8, the angle formed by the X-ray source direction and the film plane is perpendicular to the measurement The film was set and wide-angle X-ray (WAXS) measurement was performed. Measurement conditions are shown below.

The X-ray wavelength was 0.1 nm, an imaging plate (RIGAKU RAXIS VII) or a CCD camera (Hamamatsu Photonics V7739P+ORCA R2) equipped with an image intensifier was used as a detector, and the transmittance was determined from the value of the ion chamber set before and after the sample. was calculated. The obtained two-dimensional image was subjected to air scattering correction in consideration of dark current (dark noise) and transmittance. For the measurement of the camera length, cerium oxide (CeO ₂ ) was used, and Fit2D (Software from European Synchrotron Radiation Facility [http://www.esrf.eu/computing/scientific/FIT2D/]) was used to (110) plane. The azimuth profile of was calculated.

6) Long period size by small-angle X-ray scattering method

In the second hatch of the beam line BL03XU owned by the Frontier Soft Matter Development Industry-University Alliance (FSBL) in the large synchrotron radiation facility SPring-8, the vertical direction of the film is called up and down, and the horizontal direction is left and right, and the direction of the X-ray source and the film plane are The measurement film was set so that the angle formed was perpendicular, and small-angle X-ray (SAXS) measurement was performed. Measurement conditions are shown below.

The X-ray wavelength was 0.2 nm, the camera length was about 7.7 m, and an imaging plate (RIGAKU R-AXIS VII) was used as a detector to obtain a scattering image of scattering vector q in the range of 0.01 to 0.5 (nm-1). . Here, the scattering vector q is calculated by the equation q=4πsinθ/λ, where θ is half the scattering angle 2θ, π is the circumferential rate, and λ is the wavelength of the X-ray. The obtained scattering image was subjected to air scattering correction in consideration of dark current (dark noise) and transmittance in the same manner as in the WAXS measurement, and collagen separately calibrated with silver behenate was used for accurate measurement of the camera length. A profile in the width direction of the sample was calculated using the Fit2d software described above, and the scattering vector q (nm-1) was plotted on the abscissa axis and the common logarithm of intensity I (q) on the ordinate axis. Here, the calculated range of the profile was ±5 degrees from the width direction.

7) Differential Scanning Calorimetry (DSC)

Thermal measurement was performed using a differential scanning calorimeter ("DSC-60" manufactured by Shimadzu Corporation). About 5 mg was cut out from the sample film and sealed in an aluminum pan for measurement. The temperature was raised from room temperature to 230°C at a rate of 20°C/min, and the melting endothermic peak temperature and melting endothermic peak area (total heat of fusion) of the sample were measured. Here, the baseline was set so that the curves were smoothly connected at temperatures before and after melting, from the start of the endothermic peak to the end of the peak. In addition, the area of the part of 150 degreeC or less of the melting endothermic peak area was made into 150 degreeC heat of fusion.

8) Thermal shrinkage rate (unit: %)

Based on JIS Z 1712:2009, it was measured by the following method. The film substrate and the laminated film were each cut to a size of 20 mm in width and 200 mm in length in the longitudinal direction and in the transverse direction, respectively, and hung in a hot air oven at 150 ° C. and heated for 15 minutes. After heating, the length was measured on the marked line at intervals of about 50 mm, and the ratio (percentage) of the contracted length to the original length was taken as the heat shrinkage rate.

9) Young's modulus (Unit: GPa)

Based on JIS K 7127:1999, the Young's modulus of the film substrate and the laminated film in the machine direction and the transverse direction was measured at 23°C. The film base material and the laminated film were cut to a size of 15 mm in width and 200 mm in length, respectively, in the longitudinal direction and in the transverse direction, respectively, 5 pieces each, 200 mm/min. At the tensile rate, the tensile strength at the time of the tensile test was measured.

10) Impact resistance (Unit: J)

It measured at 23 degreeC using the "film impact tester (impact head: 12.7 mm)" by Toyo Seki Co., Ltd. The film substrate was cut into 5 pieces each having a size of width (horizontal direction): 105 mm and length (vertical direction): 297 mm, and impact strength was measured.

11) Thickness uniformity (thickness unevenness) (Unit: %)

A square sample having a length of 1 m was cut out from the wound film roll, and 100 samples for measurement were prepared by dividing each into 10 equal parts in the longitudinal direction and the transverse direction. The thickness of the approximately central portion of the sample for measurement was measured with a contact-type film thickness meter. The average value A of the obtained 100 points of data was calculated|required, and the difference (absolute value) B of the minimum value and maximum value was calculated|required, and the value calculated using the formula of (B/A)x100 was made into the thickness unevenness of a film.

12) Haze (unit: %)

Film substrates were measured according to JIS K7136:1999.

13) Film density (unit: g/cm ³ )

The density of the film substrate was measured by the density gradient tube method according to JIS K7112:1999.

14) Refractive index (Nx, Ny, Nz)

Using an Abbe refractometer (manufactured by Atago Co., Ltd.), the film substrate was measured at 23°C, 65% humidity, benzyl alcohol as the measurement solution, and 589 nm (sodium D line) as the measurement wavelength. The refractive indices along the vertical and horizontal directions were respectively Nx and Ny, and the refractive index in the thickness direction was Nz.

15) Plane orientation factor P

Using Nx, Ny, and Nz measured in 14) above, it was calculated from the formula: P=[(Nx+Ny)/2]-Nz.

(Composition/film thickness of inorganic thin film layer)

The compositional film thickness of the inorganic compound was measured using a fluorescence X-ray analyzer (ZSX100e manufactured by Rigaku Co., Ltd.) using a calibration curve prepared in advance. In addition, the conditions of the excitation X-ray tube were 50 kV and 70 mA.

The calibration curve was obtained in the following procedure.

Several types of films having inorganic compound thin films containing aluminum oxide and silicon oxide were produced, and the respective adhesion amounts of aluminum oxide and silicon oxide were determined by an inductively coupled plasma emission method (ICP method). Next, each film whose adhesion amount was determined was analyzed with a fluorescence X-ray analyzer (Rigaku Co., Ltd. ZSX100e, excitation X-ray tube conditions: 50 kv, 70 mA) to determine the fluorescence X-ray intensity of aluminum oxide and silicon oxide of each sample. Then, a calibration curve was prepared by determining the relationship between the fluorescence X-ray intensity and the amount of adhesion determined by ICP.

Since the adhesion amount calculated|required by ICP is basically a mass, it was converted as follows in order to make this into a film thickness composition.

The film thickness was calculated on the assumption that the density of the inorganic oxide thin film was 80% of the bulk density, and that aluminum oxide and silicon oxide each maintained their volume even in a mixed state.

The aluminum oxide content wa (mass %) in the film and the silicon oxide content ws (mass %) in the film indicate the amount of aluminum oxide deposited per unit area as Ma (g/cm ² ) and the amount of silicon oxide deposited per unit area as Ms If it is (g/cm ² ), it is obtained by the following formulas (1) and (2), respectively.

wa=100×[Ma/(Ma+Ms)] (1)

ws=100-wa (2)

That is, the adhesion amount per unit area of aluminum oxide is Ma (g/cm ² ), the bulk density thereof is ρa (3.97g/cm ³ ), the adhesion amount per unit area of silicon oxide is Ms (g/cm ² ), If the bulk density thereof is ρs (2.65 g/cm ³ ), the film thickness t (nm) is obtained by the following formula (3).

t=((Ma/(ρa×0.8)+Ms/(ρs×0.8))×10 ⁷ …Equation (3)

The value of the film thickness measured by fluorescent X-rays was close to the film thickness actually measured using a transmission electron microscope (TEM).

16) Oxygen transmission rate (mL/m ² /day/MPa)

Using an oxygen permeability measuring device (OX-TRAN2/21 manufactured by MOCON), the polypropylene film substrate, the laminated polypropylene film, and the laminated laminate were measured under conditions of a temperature of 23°C and a relative humidity of 65%. The surface on the opposite side to the inorganic thin film layer was made to be the moisture control side.

17) Moisture vapor transmission rate (g/m ² ·day)

The water vapor permeability was measured using a water vapor permeability measuring device (PERMATRAN-W3/33 manufactured by MOCON) at a temperature of 37.8 ° C. and a relative humidity of 90%. of was measured. The surface on the opposite side to the inorganic thin film layer was made to be the high humidity side.

18) Laminate Strength

Laminate strength was measured in the following procedure.

1) Production of laminated body with sealant film

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

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

In addition, the adhesive used the ether type adhesive obtained by mixing 17.9 mass % of main material (made by Toyo Morton, TM329), 17.9 mass % of curing agents (made by Toyo Morton, CAT8B), and 64.2 mass % of ethyl acetate, and the sealant film made by Toyobo Co., Ltd. A stretched polypropylene film (Pylen (registered trademark) CT P1128, thickness 30 μm) was used.

2) Measurement of laminate strength

The laminated laminate obtained above was cut into a rectangle (length 200 mm, width 15 mm) having long sides in the longitudinal direction of the 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 performed at a tensile speed of 200 mm/min under the environment was measured. The measurement was performed three times, and the average value was used as the laminate strength.

(Example 1)

As the polypropylene resin, a propylene homopolymer having Mw/Mn = 7.7, Mz + 1/Mn = 140, MFR = 5.0 g/10 min, and mesopentad fraction [mmmm] = 97.3% (manufactured by Nippon Polypro Co., Ltd.) "Novatech (registered trademark) PP SA4L": the amount of copolymerization monomer was 0 mol%; hereinafter abbreviated as "PP-1") was used.

This polypropylene-based resin is extruded into a sheet form with a T die at 250°C using a 60 mm single screw extruder, cooled and solidified with a cooling roll at 30°C, and then multiplied by 4.5 times in the longitudinal direction (longitudinal direction) at 135°C. Longitudinal stretching, then clamped at both ends, guided into a hot air oven, preheated at 170°C, and then transversely stretched 8.2 times in the transverse direction (transverse direction) at 160°C, followed by 6.7% relaxation while giving 168 It was heat treated at °C. Thereafter, corona treatment was performed on one side of the film, and it was wound up with a winder to obtain a stretched polypropylene film used as a base material of the present invention.

The thickness of the obtained film was 20 micrometers. Table 1 shows the characteristics of the polypropylene constituting the film, and Table 2 shows the film forming conditions. The physical properties of the obtained film are as shown in Table 3, and the thermal shrinkage rate was low and the Young's modulus was high. Moreover, the chart obtained by the differential scanning calorimetry (DSC) of this film is shown in FIG.

As a deposition source, particulate Al ₂ O ₃ (purity 99.5%) and SiO ₂ (purity 99.9%) having a size of about 3 to 5 mm were used, and Al ₂ O ₃ and SiO 2 were deposited on the stretched polypropylene film by an electron beam evaporation method. SiO ₂ was deposited simultaneously to form an Al2O3-SiO2 based thin film layer. As the evaporation material, a circular persimmon with a diameter of 40 mm was divided into two pieces with a carbon plate, and granular Al ₂ O ₃ and granular SiO ₂ were added to each without mixing. Using one electron gun as a heating source, each of Al2O3 and SiO2 was heated by irradiation with an electron beam in a time-division manner, heated and vaporized on the surface of the polypropylene film, and Al ₂ O ₃ and SiO ₂ were mixed and deposited. At that time, the emission current of the electron gun was 205 mA, the acceleration voltage was 6 kV, and power equivalent to 160 mA × 6 kV was supplied to the aluminum oxide and 45 mA × 6 kV to the silicon oxide. The vacuum pressure at the time of vapor deposition was 1.1×10 ^-4 Pa, and the temperature of the roll supporting the film was 23°C. The thickness of the thin film layer was deposited to be 20 nm using a crystal oscillator type film thickness meter by changing the film forming speed, and a laminated polypropylene film was obtained. The obtained film properties are shown in Table 3.

(Example 2)

As the polypropylene resin, Mw/Mn = 8.9, Mz + 1/Mn = 110, MFR = 3.0 g/10 min, [mmmm] = 97.1% propylene homopolymer ("HU300" manufactured by Samsung Total Co., Ltd.: copolymerization) Monomer amount is 0 mol%; hereinafter abbreviated as "PP-2"), except that the preheating temperature for transverse stretching is 171°C, the transverse stretching temperature is 161°C, and the heat treatment temperature after transverse stretching is 170°C. In the same manner as in Example 1, a stretched polypropylene film serving as the substrate of the present invention was obtained.

The thickness of the obtained film was 20 micrometers. Table 1 shows the structure of the polypropylene constituting the film, and Table 2 shows the film forming conditions. Physical properties of the obtained film are as shown in Table 3.

In the same manner as in Example 1, an inorganic thin film layer was deposited on the stretched polypropylene film. The obtained film properties are shown in Table 3.

(Example 3)

With respect to 90 parts by mass of the propylene homopolymer (PP-1) used in Example 1, 10 parts by mass of low molecular weight propylene having a molecular weight of 10000 (high wax “NP105” manufactured by Mitsui Chemicals Co., Ltd.: copolymerization monomer amount is 0 mol%) Added to make a total of 100 parts by mass, melt-kneaded with a 30 mm twin screw extruder, Mw / Mn = 11, Mz + 1 / Mn = 146, MFR = 7.0 g / 10 minutes, [mmmm] = 96.5% A mixture of propylene polymers ( Hereafter abbreviated as "PP-3") was obtained. A stretched polypropylene film used for the substrate of the present invention was obtained in the same manner as in Example 1 except that the pellets were used as the polypropylene resin.

The thickness of the obtained film was 20 micrometers. Table 1 shows the structure of the polypropylene constituting the film, and Table 2 shows the film forming conditions. Physical properties of the obtained film are as shown in Table 3.

In the same manner as in Example 1, an inorganic thin film layer was deposited on the stretched polypropylene film. The obtained film properties are shown in Table 3.

(Example 4)

A stretched polypropylene film used for the substrate of the present invention was obtained in the same manner as in Example 3 except that the film was stretched 5.5 times in the longitudinal direction and 12 times in the transverse direction.

The thickness of the obtained film was 20 micrometers. Table 1 shows the characteristics of the polypropylene constituting the film, and Table 2 shows the film forming conditions. Physical properties of the obtained film are as shown in Table 3.

In the same manner as in Example 1, an inorganic thin film layer was deposited on the stretched polypropylene film. The obtained film properties are shown in Table 3.

(Example 5)

The stretched polypropylene film produced in Example 1 was clipped at both ends in the film width direction in a tenter, and heat treatment was performed at 170°C for 5 minutes to obtain a stretched polypropylene film of the present invention.

The thickness of the obtained film was 20 micrometers. Table 1 shows the characteristics of the polypropylene constituting the film, and Table 2 shows the film forming conditions. Physical properties of the obtained film are as shown in Table 3.

In the same manner as in Example 1, an inorganic thin film layer was deposited on the stretched polypropylene film. The obtained film properties are shown in Table 3.

(Example 6)

As the polypropylene resin, a propylene homopolymer having Mw/Mn = 4.0, Mz + 1/Mn = 23, MFR = 6.0 g/10 min, and [mmmm] = 98.7% (amount of copolymerization monomer is 0 mol%; hereinafter "PP- Abbreviated as "4"), the stretched polypropylene film used for the base material of the present invention was obtained in the same manner as in Example 1 except for using.

The thickness of the obtained film was 20 micrometers. Table 1 shows the structure of the polypropylene constituting the film, and Table 2 shows the film forming conditions. Physical properties of the obtained film are as shown in Table 3.

In the same manner as in Example 1, an inorganic thin film layer was deposited on the stretched polypropylene film. The obtained film properties are shown in Table 3.

(Example 7)

It is a laminated film (layer B / layer A / layer B) in which layer B is laminated on both sides of layer A. Polypropylene homopolymer PP-4 shown in Table 1 is used for layer A, and the polypropylene shown in Table 1 is used for layer B. What blended 0.15 mass % of silica as an anti-blocking agent with propylene homopolymer PP-8 was used. By laminating the B layer, the lamination strength can be improved. Layer A was extruded into a sheet form from a T die at 250°C using a 60 mm extruder and layer B was a 65 mm extruder, cooled and solidified with a cooling roll at 30°C, and then stretched 4.5 times in the machine direction at 135°C. Next, in the tenter, both ends of the film in the width direction were clipped, preheated at 170°C, stretched 8.2 times in the width direction at 160°C, and heat-set at 168°C with a relaxation of 6.7%. A biaxially stretched laminated polypropylene film in which A layer and B layer were laminated one by one was obtained. Corona treatment was performed on the layer B side of the laminated polypropylene film, and it was wound up with a winder. The thickness of the obtained film was 20 micrometers. Table 1 shows the structure of the polypropylene resin raw material, and Table 2 shows the film forming conditions. Physical properties of the obtained film are as shown in Table 3.

In the same manner as in Example 1, an inorganic thin film layer was deposited on the stretched polypropylene film. The obtained film properties are shown in Table 3.

(Comparative Example 1)

As the polypropylene resin, a propylene-ethylene copolymer (Sumitomo Chemical Co., Ltd. "Sumitomo Noblen (registered trademark) FS2011DG3": 0.6 mol% of copolymerization monomer; hereinafter abbreviated as "PP-5") was used, the longitudinal stretching temperature was 125°C, the preheating temperature in transverse stretching was 168°C, and transverse stretching A stretched polypropylene film was obtained in the same manner as in Example 1, except that the temperature was 155°C and the heat treatment temperature after transverse stretching was 163°C.

The thickness of the obtained film was 20 micrometers. Table 1 shows the characteristics of the polypropylene constituting the film, and Table 2 shows the film forming conditions. Physical properties of the obtained film are as shown in Table 4.

In the same manner as in Example 1, an inorganic thin film layer was deposited on the stretched polypropylene film. The obtained film properties are shown in Table 4.

(Comparative Example 2)

A stretched polypropylene film was obtained in the same manner as in Comparative Example 1 except that the preheating temperature in transverse stretching was 171°C, the transverse stretching temperature was 160°C, and the heat treatment temperature after transverse stretching was 165°C.

The thickness of the obtained film was 20 micrometers. Table 1 shows the characteristics of the polypropylene constituting the film, and Table 2 shows the film forming conditions. Physical properties of the obtained film are as shown in Table 4.

In the same manner as in Example 1, an inorganic thin film layer was deposited on the stretched polypropylene film. The obtained film properties are shown in Table 4.

(Comparative Example 3)

As the polypropylene resin, a propylene homopolymer having Mw/Mn = 4.3, Mz + 1/Mn = 28, MFR = 0.5 g/10 min, and [mmmm] = 97.0% (copolymerization monomer amount is 0 mol%; hereinafter "PP- 6”) was used, and a stretched polypropylene film was obtained in the same manner as in Comparative Example 2.

In the same manner as in Example 1, an inorganic thin film layer was deposited on the stretched polypropylene film. The obtained film properties are shown in Table 4.

The thickness of the obtained film was 20 micrometers. Table 1 shows the structure of the polypropylene constituting the film, and Table 2 shows the film forming conditions. Physical properties of the obtained film are as shown in Table 4.

(Comparative Example 4)

As the polypropylene resin, Mw/Mn = 2.8, Mz + 1 / Mn = 9.2, MFR = 30 g / 10 min, [mmmm] = 97.9% of the polypropylene polymer (manufactured by Nippon Polypro Co., Ltd. "Novatech ( Registered trademark) PP SA03": copolymerization monomer amount is 0 mol%; hereinafter abbreviated as "PP-7"), but an attempt was made to obtain a stretched polypropylene film in the same manner as in Example 1, but the film was This fractured, and biaxial stretching could not be performed. The reason for the fracture is that orientation in the longitudinal direction progresses during stretching in the flow direction, and cracks occur during stretching in the vertical direction.

(Comparative Example 5)

Stretched polypropylene film in the same manner as in Example 1 except that the longitudinal stretching temperature was 125 ° C, the preheating temperature in transverse stretching was 168 ° C, the transverse stretching temperature was 155 ° C, and the heat treatment temperature after transverse stretching was 163 ° C. got

The thickness of the obtained film was 20 micrometers. Table 1 shows the characteristics of the polypropylene constituting the film, and Table 2 shows the film forming conditions. Physical properties of the obtained film are as shown in Table 4.

In the same manner as in Example 1, an inorganic thin film layer was deposited on the stretched polypropylene film. The obtained film properties are shown in Table 4.

The laminated polypropylene film of the present invention can be widely used for packaging applications, industrial applications, etc., and in particular, because of its excellent gas barrier properties, it is possible to reduce the thickness and achieve cost reduction and weight reduction. In addition, since the laminated polypropylene film of the present invention has high heat resistance, processing at high temperatures during coating or printing is possible, and production efficiency can be improved or coating agents, inks, laminate adhesives, etc. that have been difficult to use in the past can be used. Furthermore, the polypropylene film of the present invention is also suitable for insulating films for capacitors and motors, back sheets for solar cells, and base films for transparent conductive films such as ITO.

Claims (4)

A laminated polypropylene film comprising a polypropylene film substrate using a polypropylene resin and an inorganic thin layer containing at least one of aluminum oxide and silicon oxide or a composite oxide thereof as a main component, wherein the polypropylene resin has a molecular weight of 100,000. The amount of the following components is 35% by mass or more, the thermal shrinkage rate in the machine direction at 150°C of the laminated polypropylene film is 7% or less, and the oxygen permeability is 150 mL/m ² /day/MPa or less. Laminated polypropylene film; and
As a laminate comprising a; polyolefin film,
A laminate having an oxygen permeability of 50 mL/m ² /day/MPa or less at a temperature of 23°C and a relative humidity of 65%. The laminate according to claim 1, wherein the haze of the laminated polypropylene film is 6% or less. The laminate according to claim 1 or 2, wherein the thermal shrinkage of the laminated polypropylene film in the transverse direction at 150°C is 7% or less. delete

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