JP2022155922A - Film for package and package - Google Patents

Abstract

To provide a film for a package and a package which have oxygen barrier property, water vapor barrier property, rigidity, light shielding property and impact resistance and can be easily recycled.SOLUTION: There is provided a film for a package 1 which comprises a base material 10 composed of a biaxially oriented polypropylene film having a specific tensile modulus of elasticity and a specific water vapor permeability, a sealant material 20 which is positioned on one surface of the base material 10 in which an aluminum vapor deposition layer having a specific thickness 24 is formed on a sealant layer 22 composed of a non-stretched polypropylene film containing a specific amount of a light-shielding inorganic material and an adhesive layer 30 which is positioned between the base material 10 and the sealant material 20 and contains a specific amount of an oxygen absorber, wherein the oxygen permeability is 4.0 mL/(m2 day) or less and the transmissivity of visible light at a wavelength of 450 nm is 20% or less.SELECTED DRAWING: Figure 1

Description

TECHNICAL FIELD The present invention relates to a package film and a package.

A gas barrier film having a function of shielding oxygen and water vapor is known and widely used as a packaging material. Contents such as foods and medicines are known to deteriorate in quality due to ultraviolet rays and oxygen. For example, oils and fats are strongly affected by ultraviolet rays, and oxidative deterioration progresses. Many natural pigments are unstable against ultraviolet rays and may discolor.

In order to address such problems, for example, Patent Document 1 discloses a barrier laminate film comprising a gas barrier coating film provided on an unstretched polyolefin resin film and an aluminum deposition layer provided on the gas barrier coating film. is proposed. The invention of Patent Document 1 has oxygen barrier properties, water vapor barrier properties, light shielding properties and gloss properties equivalent to those of aluminum vapor-deposited polyethylene terephthalate (aluminum vapor-deposited PET), and attempts to improve adhesion and heat sealing properties.

JP 2013-22918 A

However, in the invention of Patent Document 1, various functions are imparted by combining a plurality of materials with different properties, so there is a problem that recycling is difficult.
In addition, packaging films are required to have rigidity that allows them to maintain a certain shape.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an easily recyclable packaging film and packaging which have oxygen barrier properties, water vapor barrier properties, rigidity, light shielding properties and impact resistance. .

As a result of intensive studies, the present inventors have found that a packaging film having the following configuration can solve the above problems.
That is, the packaging film of the present invention has the following configuration.
[1] A substrate made of a biaxially stretched polypropylene film, a sealant material in which an aluminum vapor deposition layer is formed on a sealant layer made of an unstretched polypropylene film located on one side of the substrate, the substrate and the and an adhesive layer positioned between the base material and the sealant material, wherein the base material has a tensile modulus in the MD direction of 1.8 GPa or more, and the base material has a tensile modulus in the TD direction of 3.6 GPa or more. wherein the base material has a water vapor permeability of 4.0 g/(m ² ·day) or less, the aluminum vapor deposition layer faces the base material, and the aluminum vapor deposition layer has a thickness of 20 to 100 nm. , the sealant layer contains a light-shielding inorganic substance, the content of the light-shielding inorganic substance is more than 5% by mass and less than 50% by mass with respect to the total mass of the sealant layer, and the adhesive layer is A cured product of an isocyanate-based adhesive containing a polyester polyol having a carbon-carbon double bond and a compound having an isocyanate group, wherein the isocyanate-based adhesive contains an oxygen absorber and contains the oxygen absorber. The amount is 1% by mass or more with respect to the total mass of the isocyanate adhesive, the oxygen permeability is 4.0 mL/(m ² ·day) or less, and the light transmittance of visible light with a wavelength of 450 nm is 20 % or less, film for packaging.
[2] The film for packaging according to [1], wherein the light-shielding inorganic substance is one or more selected from titanium dioxide, zinc oxide, calcium carbonate, and hydrated magnesium silicate.
[3] The film for packaging according to [1] or [2], wherein the oxygen absorber is one or more selected from conjugated diene polymer cyclized products and transition metal salts.
[4] A package in which the package film according to any one of [1] to [3] is formed into a bag.

The packaging film of the present invention has oxygen barrier properties, water vapor barrier properties, rigidity, light shielding properties and impact resistance, and can be easily recycled.

1 is a cross-sectional view of a packaging film according to an embodiment of the present invention; FIG.

[Packaging film]
The packaging film of the present invention comprises a base material made of a biaxially oriented polypropylene film, and a sealant material which is located on one side of the base material and has an aluminum deposition layer formed on a sealant layer made of a non-stretched polypropylene film. Prepare.
In the packaging film of the present invention, the substrate resin and the sealant resin are of the same type (polypropylene). Therefore, when collecting the film for packaging of the present invention, it is not necessary to collect the base material and the sealant material separately, and the film can be easily recycled.

A packaging film according to an embodiment of the present invention will be described with reference to the drawings.
The packaging film 1 shown in FIG. 1 is formed by laminating a substrate 10, a printed layer 40, an adhesive layer 30, and a sealant material 20 in this order. That is, the packaging film 1 includes a substrate 10 , a sealant material 20 located on one side of the substrate 10 , and an adhesive layer 30 located between the substrate 10 and the sealant material 20 .

The oxygen permeability of the packaging film 1 is 4.0 mL/(m ² ·day) or less, preferably 2.0 mL/(m ² ·day) or less, and 1.0 mL/(m ² ·day) or less. is more preferred. When the oxygen permeability of the film for packaging 1 is equal to or less than the above upper limit, the oxygen barrier property is excellent. The smaller the oxygen permeability of the film 1 for packaging, the better, and the lower limit of the oxygen permeability is preferably 0 mL/(m ² ·day).
The oxygen permeability of the film for packaging 1 can be measured according to the oxygen gas permeability test method by the electrolytic sensor method described in Appendix A of JIS K7126-2:2006.
The oxygen permeability of the packaging film 1 depends on the material and thickness of the base material 10, the material and thickness of the sealant material 20, the thickness of the aluminum deposition layer 24 described later, the type and content of the oxygen absorber, and these can be adjusted by a combination of

The light transmittance of visible light with a wavelength of 450 nm (hereinafter also simply referred to as "light transmittance") of the film for packaging 1 is 20% or less, preferably 10% or less, and more preferably 4% or less. When the light transmittance of the film for packaging 1 is equal to or less than the above upper limit value, the light shielding property is excellent. The smaller the light transmittance of the packaging film 1, the better, and the lower limit of the light transmittance is preferably 0%.
The light transmittance of the packaging film 1 can be measured using, for example, an ultraviolet-visible spectrophotometer.
The light transmittance of the packaging film 1 can be adjusted by the material and thickness of the sealant material 20, the thickness of the aluminum deposition layer 24 described later, the type and content of the light-shielding inorganic substance, and combinations thereof.

The thickness T1 of the packaging film ₁ is not particularly limited, but is preferably 35 to 250 μm, more preferably 40 to 200 μm, even more preferably 50 to 150 μm. When the thickness T1 is at _least the above lower limit, the strength and rigidity of the packaging film 1 are enhanced. When the thickness T1 is equal to or less than the above upper limit, the flexibility of the packaging film ₁ is enhanced, and handling becomes easy.
The thickness T1 of the packaging film ₁ can be measured, for example, with a thickness gauge or the like.

≪Base material≫
The substrate 10 consists of a biaxially oriented polypropylene film. By using a biaxially stretched polypropylene film as the base material 10, the water vapor barrier property of the film 1 for packaging can be improved. This is considered to be because the crystallinity of polypropylene can be increased by stretching the polypropylene film.
Examples of the polypropylene resin in the base material 10 include homopolypropylene, a copolymer of polypropylene and polyethylene containing about 10% by mass of polyethylene, block polypropylene, and the like. The base material 10 should just contain 50 mass % or more of polypropylene.
The base material 10 may be a single layer, or may be a multilayer in which two or more layers are laminated.

The tensile elastic modulus of the substrate 10 in the MD direction (extrusion direction when producing the film) is 1.8 GPa or more, preferably 1.9 GPa or more, and more preferably 2.0 GPa or more. When the tensile modulus of elasticity in the MD direction of the base material 10 is at least the above lower limit, the film for packaging 1 is excellent in water vapor barrier properties and rigidity. Although the upper limit of the tensile modulus of elasticity in the MD direction of the substrate 10 is not particularly limited, it is, for example, 5.0 GPa.
The tensile modulus of elasticity in the MD direction of the substrate 10 can be measured according to the test method described in JIS K7127:1999.
The tensile modulus of elasticity in the MD direction of the base material 10 can be adjusted by the material and thickness of the base material 10, molding conditions (temperature during molding, cooling time, extrusion speed), and the like.

The tensile elastic modulus of the substrate 10 in the TD direction (direction perpendicular to the MD direction) is 3.6 GPa or more, preferably 3.7 GPa or more, and more preferably 3.8 GPa or more. When the tensile modulus of elasticity in the TD direction of the base material 10 is equal to or higher than the above lower limit, the film for packaging 1 is excellent in water vapor barrier properties and rigidity. The upper limit of the tensile modulus of elasticity in the TD direction of the substrate 10 is not particularly limited, but is, for example, 7.0 GPa.
The tensile modulus of elasticity in the TD direction of the base material 10 can be measured by the same method as the tensile modulus of elasticity in the MD direction of the base material 10 .
The tensile modulus of elasticity in the TD direction of the base material 10 can be adjusted by the material and thickness of the base material 10, molding conditions (temperature during molding, cooling time, extrusion speed), and the like.

The tensile elastic modulus of the base material 10 in the TD direction is preferably greater than the tensile elastic modulus of the base material 10 in the MD direction. When the tensile elastic modulus of the base material 10 in the TD direction is higher than the tensile elastic modulus of the base material 10 in the MD direction, the water vapor barrier property and rigidity of the packaging film 1 can be further enhanced.
The tensile elastic modulus of the base material 10 in the TD direction may be the same as the tensile elastic modulus of the base material 10 in the MD direction, or may be smaller than the tensile elastic modulus of the base material 10 in the MD direction.

The water vapor permeability of the substrate 10 is 4.0 g/(m ² ·day) or less, preferably 2.0 g/(m ² ·day) or less, and more preferably 1.0 g/(m ² ·day) or less. preferable. When the water vapor transmission rate of the substrate 10 is equal to or less than the above upper limit, the film for packaging 1 is excellent in water vapor barrier properties. It is preferable that the water vapor permeability of the substrate 10 is as small as possible, and the lower limit of the water vapor permeability is preferably 0 g/(m ² ·day).
The water vapor transmission rate of the base material 10 is measured according to the test method described in JIS K7129:2008 moisture sensor method, and is shown in Table A.1. It can be measured under the test conditions 1 described in 1.
The water vapor transmission rate of the base material 10 can be adjusted by the material and thickness of the base material 10, the tensile modulus in the MD direction, the tensile modulus in the TD direction, and combinations thereof.

The thickness T ₁₀ of the base material 10 is determined in consideration of the material, configuration, etc., and is preferably 5 to 100 μm, more preferably 10 to 50 μm. When the thickness T10 of the substrate ₁₀ is equal to or greater than the above lower limit, the strength and rigidity of the packaging film 1 are enhanced. In addition, when the thickness T10 of the substrate ₁₀ is equal to or greater than the above lower limit, the water vapor barrier property of the film 1 for packaging can be enhanced. When the thickness T10 of the substrate ₁₀ is equal to or less than the above upper limit value, the flexibility of the film for packaging 1 is enhanced, and handling becomes easy.
The thickness T10 of the base material ₁₀ can be measured, for example, with a thickness gauge or the like.

≪Print layer≫
The printed layer 40 is provided on one surface of the substrate 10 . The printed layer 40 is a layer for imparting a predetermined appearance to the film for packaging 1 and enhancing beauty.
The printed layer 40 may contain a light-shielding inorganic substance, which will be described later. However, if the printed layer 40 contains a light-shielding inorganic substance, cohesive failure is likely to occur, and delamination is likely to occur. When the film for packaging 1 causes delamination, the light transmittance increases and the light shielding property decreases. In addition, when the film for packaging 1 causes delamination, the impact resistance of the package formed by making the film for packaging 1 decreases. Therefore, it is preferable that the packaging film does not include the printed layer 40 or that the printed layer 40 does not contain a light-shielding inorganic substance.
Here, "does not contain a light-shielding inorganic substance" means that the content of the light-shielding inorganic substance in the printed layer 40 is 5% by mass or less.

Although the thickness T ₄₀ of the printing layer 40 is not particularly limited, it is preferably 0.5 to 8 μm, more preferably 1 to 5 μm. When the thickness T40 of the printed layer ₄₀ is equal to or greater than the above lower limit, the film for packaging 1 can be provided with a desired appearance. When the thickness T40 of the printed layer ₄₀ is equal to or less than the above upper limit, cohesive failure of the printed layer 40 can be further suppressed.
The thickness T40 of the printed layer ₄₀ can be measured, for example, by observing a cut surface obtained by cutting the film for packaging 1 in the thickness direction with a microscope or the like.

≪Adhesive layer≫
The adhesive layer 30 is provided on the printed layer 40 . That is, the adhesive layer 30 is positioned between the substrate 10 and the sealant material 20 . The adhesive layer 30 is a cured product of an isocyanate adhesive containing a polyester polyol having a carbon-carbon double bond and a compound having an isocyanate group.
The adhesive layer 30 has carbon-carbon double bonds in the component of the isocyanate-based adhesive, and thus has oxygen absorbability. In addition, since the isocyanate-based adhesive of the present embodiment contains an oxygen absorber, the adhesive layer 30 absorbs oxygen, and oxygen can be suppressed from permeating the packaging film 1 . Therefore, the packaging film 1 having the adhesive layer 30 can further enhance the oxygen barrier property.

The isocyanate-based adhesive of the present embodiment contains a polyester polyol having a carbon-carbon double bond as a main agent, and a compound having an isocyanate group as a curing agent. That is, the isocyanate-based adhesive of this embodiment is a urethane-based adhesive containing a main agent and a curing agent.
Examples of polyester polyols include unsaturated polyesters composed of polyvalent carboxylic acid components containing at least one aromatic dicarboxylic acid or anhydride thereof. Phthalic anhydride is preferred as the aromatic dicarboxylic acid or its anhydride.
Examples of the curing agent for the isocyanate-based adhesive of the present embodiment include toluene diisocyanate (TDI), diphenylmethane diisocyanate (MDI), hexamethylene diisocyanate (HDI), isophorone diisocyanate (IPDI, 3-isocyanatomethyl-3,5, 5-trimethylcyclohexyl isocyanate) and the like.
As the curing agent, IPDI is preferable from the viewpoints of low environmental load and excellent adhesive strength.

The oxygen absorber includes one or more selected from conjugated diene polymer cyclized products and transition metal salts.
Examples of conjugated diene polymer cyclized products include 1,3-butadiene, isoprene, 2,3-dimethyl-1,3-butadiene, 2-phenyl-1,3-butadiene, 1,3-pentadiene, 2-methyl -1,3-pentadiene, 1,3-hexadiene, 4,5-diethyl-1,3-octadiene, 3-butyl-1,3-octadiene, or poly(α-pinene) obtained by cyclizing these compounds , poly(β-pinene), and polyterpenes such as poly(dipentene). As the conjugated diene polymer cyclized product, polyisoprene cyclized product is preferable.

Transition metal salts include salts of transition metal elements and organic acids.
Examples of transition metal elements include iron, nickel, copper, manganese, cobalt, rhodium, titanium, chromium, vanadium, and ruthenium. The transition metal elements are preferably iron, nickel, copper, manganese, and cobalt, more preferably manganese and cobalt, and still more preferably cobalt.
Examples of organic acids include acetic acid, stearic acid, dimethyldithiocarbamic acid, palmitic acid, 2-ethylhexanoic acid, neodecanoic acid, linoleic acid, toric acid, oleic acid, resin acid, capric acid, naphthenic acid, and the like. . As the organic acid, stearic acid, palmitic acid, neodecanoic acid, linoleic acid and oleic acid are preferred, and neodecanoic acid and oleic acid are preferred.
As the transition metal salt, cobalt neodecanoate and cobalt oleate are preferred.
These oxygen absorbents may be used alone or in combination of two or more.

The content of the oxygen absorber is 1% by mass or more, preferably 1 to 10% by mass, more preferably 3 to 8% by mass, and further 4 to 6% by mass, relative to the total mass of the isocyanate adhesive. preferable. When the content of the oxygen absorbent is at least the above lower limit, the oxygen barrier property of the film for packaging 1 can be further enhanced. When the content of the oxygen absorber is equal to or less than the above upper limit, the adhesiveness between the printed layer 40 and the sealant material 20 can be further enhanced. In addition, if the content of the oxygen absorbent is equal to or less than the above upper limit, it is advantageous in terms of cost.

The mass ratio of the main agent and curing agent in the isocyanate adhesive is preferably 100:103 to 100:150, more preferably 100:103 to 100:130, even more preferably 100:105 to 100:125. When the mass ratio of the main agent and the curing agent is equal to or higher than the above lower limit, the adhesiveness between the base material 10 and the sealant material 20 can be further enhanced. When the mass ratio of the main agent and the curing agent is equal to or less than the above upper limit, the water vapor barrier property of the film 1 for packaging can be further enhanced.

The content of unreacted isocyanate groups in the adhesive layer 30 is preferably 3 to 30 mol%, more preferably 3 to 20 mol%, and more preferably 5 to 10 mol% of the content of the generated urethane groups. More preferred. When the content of the unreacted isocyanate groups is at least the above lower limit, the unreacted isocyanate groups absorb water vapor, so that the water vapor barrier properties of the packaging film 1 can be further enhanced. When the content of unreacted isocyanate groups is equal to or less than the above upper limit, the adhesiveness between the base material 10 and the sealant material 20 can be further enhanced, which is advantageous in terms of cost.
The content of unreacted isocyanate groups can be measured with a Fourier transform infrared spectrophotometer (FTIR).
Specifically, the film for packaging 1 is irradiated with infrared light, and transmission mapping measurement is performed using an infrared microscope. The spectrum obtained by the transmission mapping measurement is analyzed in the infrared wavelength range of 2,500 to 25,000 nm (2.5 to 25 μm), and the peak height of the urethane group and the isocyanate group in the adhesive layer 30 are determined. The content of unreacted isocyanate groups relative to the content of urethane groups can be determined by determining the ratio of the peak height.

The isocyanate-based adhesive may be a one-liquid type adhesive or a two-liquid type adhesive. As the isocyanate-based adhesive, a two-liquid type adhesive consisting of a main agent and a curing agent is preferable from the viewpoint of high curing speed and excellent adhesive strength.
The isocyanate-based adhesive may contain components other than the main agent, curing agent, and oxygen absorber. Other components include additives commonly used in adhesives, organic solvents, and the like. The content of other components is preferably 0 to 20% by mass with respect to the total mass of the isocyanate adhesive.

The thickness T ₃₀ of the adhesive layer 30 is, for example, preferably 1.5-5.0 μm, more preferably 2.0-4.0 μm. When the thickness T30 of the adhesive layer ₃₀ is at least the above lower limit, the adhesiveness between the base material 10 and the sealant material 20 can be further enhanced. In addition, when the thickness T30 of the adhesive layer ₃₀ is at least the above lower limit, the oxygen barrier property and water vapor barrier property of the packaging film 1 can be further enhanced. When the thickness T30 of the adhesive layer ₃₀ is equal to or less than the above upper limit, cohesive failure of the adhesive layer 30 can be suppressed.
The thickness T30 of the adhesive layer ₃₀ can be measured, for example, by observing a cut surface obtained by cutting the film for packaging 1 in the thickness direction with a microscope or the like.

≪Sealant material≫
The sealant material 20 is formed by forming an aluminum deposition layer 24 on a sealant layer 22 made of unstretched polypropylene film. That is, the sealant material 20 is an aluminum vapor-deposited unstretched polypropylene film. The aluminum deposition layer 24 faces the substrate 10 .
By using an aluminum vapor-deposited unstretched polypropylene film as the sealant material 20, the packaging film 1 is excellent in oxygen barrier properties, water vapor barrier properties, light shielding properties, and impact resistance.

The thickness T ₂₀ of the sealant material 20 is determined in consideration of the material, construction, etc., and is preferably 5 to 150 μm, more preferably 10 to 100 μm, and even more preferably 20 to 60 μm. When the thickness T20 of the sealant material ₂₀ is at least the above lower limit, the oxygen barrier properties, water vapor barrier properties, and light shielding properties of the film for packaging 1 can be further enhanced. When the thickness T20 of the sealant material ₂₀ is equal to or less than the above upper limit value, the flexibility of the packaging film 1 is enhanced, and handling is facilitated.
The thickness T20 of the sealant material ₂₀ can be measured, for example, with a thickness gauge.

<Sealant layer>
The sealant layer 22 is made of unstretched polypropylene film. Examples of the polypropylene resin in the unstretched polypropylene film include homopolypropylene, a copolymer of polypropylene and polyethylene containing about 10% by mass of polyethylene, block polypropylene, and the like. The sealant layer 22 may contain 50% by mass or more of polypropylene.
An unstretched polypropylene film is excellent in heat sealability. Therefore, by using the unstretched polypropylene film as the sealant layer 22, the sealing performance when sealing the packaging film 1 can be enhanced. As a result, the impact resistance of the package formed by bagging the film for package 1 can be enhanced.
The sealant layer 22 may be a single layer or a multilayer in which two or more layers are laminated.

The sealant layer 22 contains a light shielding inorganic substance. The sealant layer 22 can reduce the light transmittance of the packaging film 1 by containing a light-shielding inorganic substance. Therefore, the sealant layer 22 containing a light-shielding inorganic substance can enhance the light-shielding property of the film for packaging 1 .
A light-shielding inorganic substance is an inorganic substance that shields ultraviolet rays and visible light by scattering and reflection. Examples of light-shielding inorganic substances include titanium dioxide, zinc oxide, calcium carbonate, and talc (hydrous magnesium silicate). As the light-shielding inorganic substance, titanium dioxide is preferable because it has a high refractive index and can more easily shield ultraviolet rays and visible light.

The content of the light-shielding inorganic substance is more than 5% by mass and less than 50% by mass, preferably 10% by mass or more and 45% by mass or less, and 15% by mass or more and 40% by mass or less, relative to the total mass of the sealant layer 22. more preferred. When the content of the light-shielding inorganic substance is more than the above lower limit, the light-shielding property of the packaging film 1 can be further enhanced. When the content of the light-shielding inorganic substance is less than the above upper limit, delamination (delamination) between the sealant layer 22 and the vapor-deposited aluminum layer 24 can be suppressed, and a decrease in impact resistance of the packaging film 1 can be suppressed.

When the light-shielding inorganic substance is a powder, the average primary particle size of the light-shielding inorganic substance is, for example, preferably 100 to 500 nm, more preferably 200 to 400 nm. When the average primary particle size of the light-shielding inorganic substance is at least the above lower limit, the light-shielding property of the packaging film 1 can be further enhanced. When the average primary particle size of the light-shielding inorganic substance is equal to or less than the above upper limit, the impact resistance of the packaging film 1 can be further enhanced.
In the present specification, the average primary particle size is determined by analyzing images taken with a transmission electron microscope, for example.

The thickness T ₂₂ of the sealant layer 22 is determined in consideration of the material and the like, and is preferably 5 to 100 μm, more preferably 5 to 90 μm, and even more preferably 10 to 50 μm. When the thickness T22 of the sealant layer ₂₂ is at least the above lower limit, the impact resistance of the packaging film 1 can be further enhanced. When the thickness T22 of the sealant layer ₂₂ is equal to or less than the above upper limit value, the flexibility of the packaging film 1 is enhanced, and handling becomes easy.
The thickness T22 of the sealant layer ₂₂ can be measured, for example, with a thickness gauge.

<Aluminum deposition layer>
The aluminum deposition layer 24 has oxygen barrier properties, water vapor barrier properties, and light shielding properties. That is, the aluminum deposition layer 24 in this embodiment has a role of suppressing transmission of oxygen, water vapor, ultraviolet rays and visible light.
In this embodiment, the aluminum deposition layer 24 is formed on the sealant layer 22 instead of the base material 10 . Therefore, by providing the printed layer 40 on the substrate 10 , it is possible to impart a predetermined appearance to the packaging film 1 without being shielded by the aluminum deposition layer 24 . As a result, the appearance of the packaging film 1 can be made beautiful.
In addition, in the present embodiment, by using the vapor-deposited aluminum layer 24 and the light-shielding inorganic substance in combination, the light-shielding property of the packaging film 1 can be further enhanced, and the packaging film 1 is used to form a package. It is possible to suppress the deterioration of the contents of the container due to ultraviolet rays and the like.

The thickness T ₂₄ of the aluminum deposition layer 24 is 20 to 100 nm, preferably 35 to 85 nm, more preferably 50 to 70 nm. When the thickness T24 of the aluminum deposition layer ₂₄ is equal to or greater than the above lower limit, the oxygen barrier properties, water vapor barrier properties, and light shielding properties of the film for packaging 1 are likely to be enhanced. When the thickness T24 of the aluminum deposition layer ₂₄ is equal to or less than the above upper limit, it is possible to suppress the occurrence of delamination due to cohesive failure. Therefore, the decrease in the impact resistance of the packaging film 1 can be suppressed. In addition, if the thickness T24 of the aluminum deposition layer ₂₄ is equal to or less than the above upper limit, it is advantageous in terms of cost.
The thickness T24 of the aluminum deposition layer ₂₄ can be measured, for example, by observing a cut surface obtained by cutting the packaging film 1 in the thickness direction with a microscope or the like.

[Method for producing packaging film]
The method for manufacturing the packaging film 1 comprises a step of obtaining the base material 10 (base material manufacturing process), a process of providing the printed layer 40 on the base material 10 (printing process), and a process of obtaining the sealant layer 22 (sealant layer manufacturing process). a step of providing a sealant layer 22 with an aluminum deposition layer 24 to obtain a sealant material 20 (a sealant manufacturing step); and obtaining a laminate by laminating the base material 10 and the sealant material 20 via an adhesive. It has a step (laminate manufacturing step) and a step of subjecting the laminate to a heat treatment (heat treatment step).

≪Base material manufacturing process≫
A method for obtaining the substrate 10 in the substrate manufacturing process is selected from conventionally known methods such as an inflation method, a T-die method, a co-extrusion method, etc., depending on the material, configuration, etc. of the substrate 10 .

≪Printing process≫
The printing process is not particularly limited, and various printing methods such as offset printing, gravure printing, flexographic printing, screen printing, and inkjet printing can be employed.

≪Sealant layer manufacturing process≫
In the sealant layer manufacturing process, a light-shielding inorganic substance is added to the resin that is the raw material of the sealant layer 22 . The amount of the light-shielding inorganic substance added is more than 5% by mass and less than 50% by mass, preferably 10% by mass or more and 45% by mass or less, and 15% by mass with respect to the total mass of the resin composition containing the resin as a raw material. More preferably, the content is 40% by mass or less.
A method for obtaining the sealant layer 22 is selected from conventionally known methods such as an inflation method, a T-die method, a co-extrusion method, etc., depending on the material, configuration, and the like.

≪Sealant manufacturing process≫
In the sealant manufacturing process, an aluminum deposition layer 24 is provided on the sealant layer 22 . The method of providing the aluminum deposition layer 24 on the sealant layer 22 is not particularly limited, and a conventionally known vacuum deposition method can be applied (vapor deposition operation).
In the vapor deposition operation, the degree of vacuum in the vapor deposition chamber is preferably 0.1 to 0.5 Pa, for example.
In the vapor deposition operation, the conveying speed of the unstretched polypropylene film is preferably, for example, 100 to 400 m/min.
Through the vapor deposition operation, the sealant material 20 in which the aluminum vapor deposition layer 24 is formed on the sealant layer 22 is obtained.

≪Laminate production process≫
In the laminate manufacturing process, a laminate of the base material 10 and the sealant material 20 is manufactured. A method for laminating the base material 10 and the sealant material 20 in the laminate manufacturing process is selected from conventionally known methods such as a dry lamination method, for example.
In the dry lamination method, for example, an adhesive is applied to the aluminum deposition layer 24 of the sealant material 20 to be laminated, the base material 10 and the sealant material 20 are laminated via the adhesive, and each layer is pressed and dried. A laminate is thus obtained. The obtained laminate is wound into a roll, for example.

≪Heat treatment process≫
After manufacturing the laminate as described above, the laminate is subjected to heat treatment in the heat treatment step. Curing of the adhesive is accelerated by heat-treating the laminate.

The temperature of the heat treatment is, for example, preferably 30 to 60°C, more preferably 35 to 50°C.
When the temperature of the heat treatment is equal to or higher than the above lower limit, the curing of the adhesive is sufficiently accelerated, and the adhesiveness between the base material 10 and the sealant material 20 can be further enhanced. When the temperature of the heat treatment is equal to or lower than the above upper limit, it is possible to suppress thermal damage to each layer constituting the laminate, and to further suppress deterioration of the oxygen barrier properties and water vapor barrier properties of the packaging film 1 .

The heat treatment time is, for example, preferably 5 hours or longer, more preferably 5 to 96 hours, and even more preferably 12 to 48 hours. When the heat treatment time is equal to or longer than the above lower limit, the curing of the adhesive is sufficiently promoted, and the adhesiveness between the base material 10 and the sealant material 20 can be further enhanced. Productivity of the film 1 for packaging can be improved as the time of heat processing is below the said upper limit.
The heat treatment of the laminate can be performed in a conventionally known constant temperature room or the like.
Note that the heat-treated laminate and the unheated laminate can be distinguished by, for example, analyzing the curing state of the adhesives of both by FTIR or nuclear magnetic resonance (NMR).

≪Package≫
The package of this embodiment is produced by bagging the film for package 1 of this embodiment. As the package, for example, a bag made by heat-sealing the sealant layers 22 of the film for package 1 can be used.
Examples of the form of the package include a folded bag, a three-sided sealed bag, a four-sided sealed bag, a gusset bag, a stand bag, and these bags with zippers.
Further, for example, the package includes a container body having an opening and a lid made of the package film 1, and the sealant layer 22 is in contact with the periphery of the opening of the container body. is heat-sealed to the container body. As the material of the container body in this case, polypropylene is preferable from the viewpoint of easy recycling.

As described above, in the packaging film 1 of the present embodiment, the tensile modulus of elasticity of the substrate 10 in the MD direction is 1.8 GPa or more, and the tensile elasticity modulus of the substrate 10 in the TD direction is 3.6 GPa or more. Therefore, it has excellent water vapor barrier properties and rigidity.
Since the film for packaging 1 of the present embodiment includes the sealant material 20 in which the aluminum deposition layer 24 is formed on the sealant layer 22, it has excellent oxygen barrier properties, water vapor barrier properties, and light shielding properties.
Since the sealant layer 22 of the packaging film 1 of the present embodiment contains a light-shielding inorganic substance, it has excellent light-shielding properties.
The packaging film 1 of the present embodiment uses an isocyanate-based adhesive containing a polyester polyol having a carbon-carbon double bond and a compound having an isocyanate group, and thus has excellent oxygen absorbability. Therefore, the film for packaging 1 of the present embodiment has excellent oxygen barrier properties.
Since the isocyanate-based adhesive contains an oxygen absorbent, the packaging film 1 of the present embodiment is excellent in oxygen absorbability. Therefore, the film for packaging 1 of the present embodiment has excellent oxygen barrier properties.
In the packaging film 1 of the present embodiment, the base material 10 and the sealant material 20 are both made of polypropylene. As described above, the packaging film 1 of the present embodiment is a monomaterial (single material), and therefore can be easily recycled.
A package formed by bagging the film 1 for packaging of the present embodiment uses the substrate 10 having a specific tensile elastic modulus, and therefore has excellent water vapor barrier properties.
A package formed by bagging the film 1 for packaging of the present embodiment has excellent rigidity because the substrate 10 having a specific tensile modulus is used. Therefore, the package of the present embodiment can maintain a constant shape, and can be suitably used as a gusset bag or a stand bag that requires self-standing (standing property).
Since the sealant layer 22 is used as the sealant layer, the package obtained by making the package film 1 of the present embodiment is excellent in impact resistance.
Since the package formed by bagging the film for package 1 of the present embodiment includes the printed layer 40, it can be provided with a predetermined appearance, and the appearance can be made beautiful.
A package obtained by bagging the film for package 1 of the present embodiment is a monomaterial, and therefore can be easily recycled.

[Other embodiments]
Although the printing layer is provided in the above-described embodiments, the present invention is not limited to this, and the printing layer may be omitted. However, from the viewpoint of making the appearance of the package more beautiful, the package film preferably has a printed layer.
In the above-described embodiment, the substrate 10 is a single layer, but the present invention is not limited to this, and may be a multilayer substrate.
In the embodiment described above, the sealant layer 22 is a single layer, but the present invention is not limited to this, and may be a multiple layer sealant layer.

EXAMPLES The present invention will be described below with reference to examples, but the present invention is not limited to the following examples.
The materials and test conditions used in this example are as follows.

[Materials used]
≪Base material≫
· OPP1: Biaxially oriented polypropylene film, Pyrene (registered trademark) film-OT (trade name), manufactured by Toyobo Co., Ltd., thickness 30 μm, tensile modulus (MD direction 2.1 GPa / TD direction 3.9 GPa).
· OPP2: Biaxially oriented polypropylene film, Pyrene (registered trademark) film-OT (trade name), manufactured by Toyobo Co., Ltd., thickness 20 μm, tensile modulus (MD direction 1.8 GPa / TD direction 3.6 GPa).
OPP3: Biaxially oriented polypropylene film, Torayfan (registered trademark) BO (trade name), manufactured by Toray Advanced Film Co., Ltd., thickness 20 μm, tensile modulus (MD direction 1.5 GPa/TD direction 3.2 GPa).

≪Sealant material≫
<Sealant layer>
· CPP1: Unstretched polypropylene film, Taiko (registered trademark) FC (trade name), manufactured by Futamura Chemical Co., Ltd., thickness 30 µm.
- CPP2: Unstretched polypropylene film, Taiko (registered trademark) FC (trade name), manufactured by Futamura Chemical Co., Ltd., 30 μm thick (coextruded layer in which three layers of CPP with a thickness of 10 μm are laminated, a light-shielding inorganic substance in the intermediate layer ).
<Light-shielding inorganic substance>
- Titanium dioxide: Titanium oxide (trade name), manufactured by Sakai Chemical Industry Co., Ltd., average primary particle size (average particle size of 100 primary particles) of 200 nm.
Zinc oxide: Type 1 (trade name), manufactured by Sakai Chemical Industry Co., Ltd., average primary particle size (average particle size of 100 primary particles) 750 nm.
· Calcium carbonate: Neolite (trade name), manufactured by Takehara Chemical Industry Co., Ltd., average primary particle size (average particle size of 100 primary particles) 80 nm.
<Comparison component of light shielding inorganic substance>
· Triazole: Sumisorb (registered trademark) (trade name), manufactured by Sumika Chemtex Co., Ltd.
<Aluminum evaporation layer>
(Vapor deposition conditions)
・Vapor deposition device name: Winding type vacuum deposition device EWA series (trade name), manufactured by ULVAC, Inc.
Evaporation source: aluminum.
- Degree of vacuum in the vapor deposition chamber: 0.2 Pa.
- Film transport speed: 200 m/min.

≪Adhesive layer≫
<Main agent>
・Saturated polyester: manufactured by Nippon Synthetic Chemical Co., Ltd.
・Phthalic anhydride: manufactured by Junsei Chemical Co., Ltd.
<Curing agent>
IPDI: Isophorone diisocyanate, Takenate (registered trademark), manufactured by Mitsui Chemicals, Inc.
- TDI: Toluene diisocyanate, Takenate (registered trademark), manufactured by Mitsui Chemicals, Inc.
<Oxygen absorber>
- Conjugated diene: a conjugated diene polymer cyclized product (polyisoprene cyclized product).
- Transition metal: transition metal salt, cobalt neodecanoate, manufactured by Nippon Kagaku Sangyo Co., Ltd.

[Examples 1 to 9, Comparative Examples 1 to 8]
A printed layer is provided on the substrate shown in Table 1, and an adhesive containing an oxygen absorber shown in Table 1 is applied to the aluminum vapor deposited layer of the sealant material formed with an aluminum vapor deposited layer having a thickness shown in Table 1 and laminated. to obtain a laminate. This laminate was heat-treated at 40° C. for 72 hours to produce films for packaging according to the structures of Examples 1-9 and Comparative Examples 1-8. "//" in the laminate structure indicates that the printed layer and the adhesive layer are provided between the substrate and the sealant material.
In addition, "-" in the table indicates that the material is not included.

[Evaluation method]
<Evaluation of water vapor barrier property>
For the substrate of each example, according to the test method described in JIS K7129:2008 moisture sensor method, Table A. The water vapor transmission rate was measured under the test conditions 1 described in 1, and the water vapor barrier property was evaluated based on the following evaluation criteria. Tables 1 and 2 show the results.
"Evaluation criteria"
A: Water vapor permeability of 2.0 g/(m ² ·day) or less.
◯: water vapor permeability more than 2.0 g/(m ² ·day) and 4.0 g/(m ² ·day) or less.
x: More than 4.0 g/(m ² ·day) of water vapor permeability.

<Evaluation of oxygen barrier properties>
For the film for packaging obtained in each example, the oxygen permeability was measured according to the oxygen gas permeability test method by the electrolytic sensor method described in Annex A of JIS K7126-2: 2006, and the following evaluation criteria were used. The oxygen barrier properties were evaluated based on the results. Table 2 shows the results.
"Evaluation criteria"
A: Oxygen permeability of 2.0 mL/(m ² ·day) or less.
◯: Oxygen permeability more than 2.0 mL/(m ² ·day) and 4.0 mL/(m ² ·day) or less.
x: More than 4.0 mL/(m< ² >*day) of oxygen permeability.

<Evaluation of light shielding>
For the packaging film obtained in each example, an ultraviolet-visible spectrophotometer (manufactured by Shimadzu Corporation, UV-2600i) was used to measure the light transmittance of visible light at a wavelength of 450 nm. evaluated the sex. Table 2 shows the results.
"Evaluation criteria"
A: Light transmittance of 4% or less.
◯: Light transmittance of more than 4% and 10% or less.
Δ: Light transmittance more than 10% and 20% or less.
x: More than 20% of light transmittance.

<Evaluation of impact resistance>
The sealant layer of the packaging film obtained in each example was heat-sealed (sealing temperature: 180°C, sealing time: 1 second, sealing pressure: 3.5 kg/cm ² , sealing width: 10 mm) to obtain a 130 mm × 170 mm layer. A three-sided seal bag (flat bag) was produced. This flat bag was filled with 180 mL of water, and the opening was heat-sealed under the same conditions as above to obtain an evaluation sample. This evaluation sample was vertically dropped from a height of 1.2 m onto a concrete surface, and this operation was repeated three times (drop strength test). Among the 10 samples for evaluation, the number of samples in which leakage of the contents was observed (the number of broken bags) was counted, and the impact resistance was evaluated based on the following evaluation criteria. Table 2 shows the results.
"Evaluation criteria"
A: The number of broken bags is 0.
○: The number of broken bags is 1 or 2.
x: The number of broken bags is 3 or more.

<Comprehensive evaluation>
Based on the evaluation results of the above-described evaluation of water vapor barrier properties, evaluation of oxygen barrier properties, evaluation of light shielding properties, and evaluation of impact resistance, the films for packaging of each example were comprehensively evaluated according to the following evaluation criteria. Those with a comprehensive evaluation of "⊚" or "◯" were regarded as acceptable.
"Evaluation criteria"
(double-circle): All the evaluation results are "(double-circle)."
◯: One or more “◯” evaluation results and no “X” evaluation results.
x: There is one or more "x" in the evaluation result.

As shown in Tables 1 and 2, the packaging films and packages of Examples 1 to 9 to which the present invention is applied have an overall evaluation of "◎" or "○", oxygen barrier properties, water vapor barrier properties, and rigidity. , It was confirmed that the light shielding property and the impact resistance are excellent.
On the other hand, Comparative Example 1 using a base material having a tensile modulus outside the range of the present invention was poor in rigidity, had a high water vapor permeability, and was evaluated as "poor" in water vapor barrier properties. Comparative Example 2, in which the adhesive layer did not contain an oxygen absorber, had a high oxygen permeability and an evaluation of "x" for the oxygen barrier property. Comparative Example 3, in which the content of the light-shielding inorganic substance was outside the range of the present invention, had a high light transmittance and was evaluated as "poor" in light-shielding properties. In Comparative Example 4, in which the content of the light-shielding inorganic substance was outside the range of the present invention, the number of broken bags was large and the evaluation of impact resistance was "x". Comparative Example 5, in which the film thickness of the vapor-deposited aluminum layer was outside the range of the present invention, had a high oxygen permeability and was evaluated as "poor" in terms of oxygen barrier properties. Comparative Example 6, in which the printed layer contained a light-shielding inorganic substance and the sealant layer (sealant material) did not contain a light-shielding inorganic substance, caused delamination, and the light-shielding property evaluation and impact resistance evaluation were "x". . Comparative Example 7, which contained triazole instead of the light-shielding inorganic substance, had a high light transmittance and was evaluated as "x" for light-shielding properties. In Comparative Example 8, in which the film thickness of the vapor-deposited aluminum layer was outside the range of the present invention, the number of broken bags was large, and the evaluation of impact resistance was "x".

From the above results, it was confirmed that by applying the present invention, excellent oxygen barrier properties, water vapor barrier properties, rigidity, light shielding properties and impact resistance are obtained.

1 packaging film 10 base material 20 sealant material 22 sealant layer 24 aluminum deposition layer 30 adhesive layer 40 printed layer

Claims (4)

A substrate made of a biaxially oriented polypropylene film,
A sealant material in which an aluminum deposition layer is formed on a sealant layer made of an unstretched polypropylene film, located on one side of the base material;
an adhesive layer positioned between the substrate and the sealant material;
The base material has a tensile modulus in the MD direction of 1.8 GPa or more,
The base material has a tensile modulus in the TD direction of 3.6 GPa or more,
The water vapor permeability of the base material is 4.0 g/(m ² ·day) or less,
The aluminum deposition layer faces the base material,
The aluminum deposition layer has a thickness of 20 to 100 nm,
The sealant layer contains a light-shielding inorganic substance,
The content of the light-shielding inorganic substance is more than 5% by mass and less than 50% by mass with respect to the total mass of the sealant layer,
The adhesive layer is a cured product of an isocyanate adhesive containing a polyester polyol having a carbon-carbon double bond and a compound having an isocyanate group,
The isocyanate adhesive contains an oxygen absorber,
The content of the oxygen absorber is 1% by mass or more with respect to the total mass of the isocyanate adhesive,
Oxygen permeability is 4.0 mL / (m ² day) or less,
A packaging film having a light transmittance of 20% or less for visible light having a wavelength of 450 nm. 2. The packaging film according to claim 1, wherein said light-shielding inorganic substance is one or more selected from titanium dioxide, zinc oxide, calcium carbonate and hydrated magnesium silicate. The packaging film according to claim 1 or 2, wherein the oxygen absorbent is one or more selected from conjugated diene polymer cyclized products and transition metal salts. A package formed from the package film according to any one of claims 1 to 3.

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