JP7696743B2 - Packaging film and packaging material - Google Patents

Description

The present invention relates to a film for packaging and a packaging body.

Gas barrier films that have the ability to block oxygen and water vapor are known and are widely used as packaging materials. It is known that ultraviolet light and oxygen can cause a deterioration in the quality of contents such as food and medicine. For example, fats and oils are strongly affected by ultraviolet light, and oxidative deterioration progresses. Many natural pigments are unstable when exposed to ultraviolet light, and there is a risk of discoloration.

In response to these problems, for example, Patent Document 1 proposes a barrier laminate film that includes a gas barrier coating film provided on an unstretched polyolefin resin film and an aluminum vapor-deposited layer provided on the gas barrier coating film. The invention of Patent Document 1 has oxygen barrier properties, water vapor barrier properties, light blocking properties, and gloss properties equivalent to those of aluminum vapor-deposited polyethylene terephthalate (aluminum vapor-deposited PET), and also has improved adhesion and heat sealability.

JP 2013-22918 A

However, the invention in Patent Document 1 has the problem that recycling is difficult because it combines multiple materials with different properties to impart various functions.

The present invention was made in consideration of the above circumstances, and aims to provide a packaging film and packaging body that have oxygen barrier properties, water vapor barrier properties, light blocking properties, and impact resistance, and that can be easily recycled.

As a result of extensive investigations, 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 film for packaging comprising: a substrate having a coating layer containing 0.5 to 5.0 g/ ^m2 of titanium dioxide formed on the surface of a base layer made of a biaxially oriented polypropylene film; a sealant material located on one side of the substrate and having an aluminum vapor-deposited layer formed on one side of a sealant layer made of a non-oriented polypropylene film; and an adhesive layer located between the substrate and the sealant material, wherein the aluminum vapor-deposited layer faces the substrate and has a thickness of 20 to 100 nm, 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, the isocyanate-based adhesive containing an oxygen absorber, and the content of the oxygen absorber is 1 mass% or more relative to the total mass of the isocyanate-based adhesive.
[2] A film for packaging comprising: a substrate which is a biaxially oriented polypropylene film; a sealant material which is located on one side of the substrate and which has an aluminum vapor-deposited layer formed on one side of a sealant layer made of a non-oriented polypropylene film; and an adhesive layer which is located between the substrate and the sealant material, wherein the substrate contains titanium dioxide, and the titanium dioxide content is more than 5% by mass and less than 50% by mass with respect to the total mass of the substrate; the aluminum vapor-deposited layer faces the substrate and has a thickness of 20 to 100 nm; the adhesive layer is a cured product of an isocyanate-based adhesive which contains a polyester polyol having a carbon-carbon double bond and a compound having an isocyanate group; the isocyanate-based adhesive contains an oxygen absorber, and the content of the oxygen absorber is 1% by mass or more with respect to the total mass of the isocyanate-based adhesive.
[3] The film for packaging according to [1] or [2], wherein the oxygen absorber is at least one selected from the group consisting of a conjugated diene polymer cyclized product and a transition metal salt.
[4] A packaging body produced using the packaging film according to any one of [1] to [3].

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

1 is a cross-sectional view of a packaging film according to a first embodiment of the present invention. FIG. 3 is a cross-sectional view of a packaging film according to a second embodiment of the present invention.

The packaging film of the present invention comprises a substrate having a base layer made of a biaxially oriented polypropylene film and a coating layer containing titanium dioxide formed thereon, and a sealant material located on one side of the substrate and having a sealant layer made of a non-oriented polypropylene film and an aluminum vapor deposition layer formed thereon.
In the packaging film of the present invention, the resin of the substrate and the resin of the sealant are the same type (polypropylene), so that when the packaging film of the present invention is collected, it is not necessary to collect the substrate and the sealant separately, and the film can be easily recycled.

[First embodiment]
<Packaging film>
The packaging film according to the first embodiment of the present invention will be described with reference to the drawings.
1 is formed by laminating a substrate 10, an adhesive layer 30, and a sealant material 20 in this order. That is, the film 1 for packaging includes the substrate 10 having a coating layer 14 formed on the surface of a base layer 12, the sealant material 20 located on one side of the substrate 10, and the adhesive layer 30 located between the substrate 10 and the sealant material 20. The sealant material 20 is formed by forming an aluminum vapor deposition layer 24 on one side of a sealant layer 22. The surface of the coating layer 14 of the substrate 10 faces the surface of the aluminum vapor deposition layer 24 of the sealant material 20.

The oxygen permeability of the film for packaging 1 is preferably 4.0 mL/( ^m2 ·day) or less, more preferably 2.0 mL/( ^m2 ·day) or less, and even more preferably 1.0 mL/( ^m2 ·day) or less. When the oxygen permeability of the film for packaging 1 is equal to or less than the upper limit, the film has excellent oxygen barrier properties. The smaller the oxygen permeability of the film for packaging 1, the more preferable, and the lower limit of the oxygen permeability is preferably 0 mL/( ^m2 ·day).
The oxygen permeability of the packaging film 1 can be measured in accordance with the test method for oxygen gas permeability using an electrolytic sensor method described in Appendix A of JIS K7126-2:2006.
The oxygen permeability of the packaging film 1 can be adjusted by the material and thickness of the substrate 10, the material and thickness of the sealant material 20, the thickness of the aluminum vapor deposition layer 24, the type and content of the oxygen absorbent, and combinations of these.

The light transmittance of the film 1 for packaging bodies for visible light having a wavelength of 450 nm (hereinafter also simply referred to as "light transmittance") is preferably 20% or less, more preferably 10% or less, and even more preferably 4% or less. When the light transmittance of the film 1 for packaging bodies is equal to or less than the above upper limit, the film 1 for packaging bodies has excellent light blocking properties. The smaller the light transmittance of the film 1 for packaging bodies, the more preferable it is, and the lower limit of the light transmittance is preferably 0%.
The light transmittance of the packaging film 1 can be measured, for example, by using an ultraviolet-visible spectrophotometer.
The light transmittance of the packaging film 1 can be adjusted by the material and thickness of the coating layer 14, the content of the light-blocking inorganic substance, the thickness of the aluminum vapor deposition layer 24 described below, and a combination of these.

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, and even more preferably 50 to 150 μm. When the thickness _T1 is equal to or greater than the lower limit, the strength of the packaging film 1 is increased. When the thickness _T1 is equal to or less than the upper limit, the flexibility of the packaging film 1 is increased, making it easier to handle.
The thickness _T1 of the packaging film 1 can be measured, for example, by a thickness gauge.

<Base material>
The substrate 10 is formed by forming a coating layer 14 on one side of a base layer 12 made of a biaxially oriented polypropylene film. The coating layer 14 is located between the base layer 12 and a sealant material 20. That is, the coating layer 14 is formed on the surface of the base layer 12 facing the sealant material 20.

The thickness _T10 of the substrate 10 is determined taking into consideration the material, configuration, etc., and is, for example, 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 of the packaging film 1 is increased. 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 packaging film 1 is improved. When the thickness _T10 of the substrate 10 is equal to or less than the above upper limit, the flexibility of the packaging film 1 is increased, making it easier to handle.
The thickness _T10 of the substrate 10 can be measured, for example, by a thickness gauge.

(base layer)
The base layer 12 is made of a biaxially oriented polypropylene film. By using a biaxially oriented polypropylene film as the base layer 12, it is possible to improve the water vapor barrier property of the packaging film 1. This is thought to be because the crystallinity of polypropylene can be increased by stretching the polypropylene film.
Examples of the polypropylene in the base layer 12 include homopolypropylene, a copolymer of polypropylene and polyethylene containing about 10% by mass of polyethylene, block polypropylene, etc. The base layer 12 may contain 50% by mass or more of polypropylene.
The base layer 12 may be a single layer, or may be a multi-layer in which two or more layers are laminated.

The orientation degree α of the base layer 12 in the MD direction (the flow direction when the film is manufactured) is preferably 0.5 to 2.5, more preferably 0.7 to 2.0, and even more preferably 1.0 to 1.5. When the orientation degree α is equal to or greater than the above-mentioned lower limit, the packaging film 1 has better water vapor barrier properties. When the orientation degree α is equal to or less than the above-mentioned upper limit, the impact resistance of a package produced from the packaging film 1 can be further improved.
The orientation degree β of the base layer 12 in the TD direction (direction perpendicular to the MD direction) is preferably 0.2 to 2.5, more preferably 0.5 to 2.0, and even more preferably 0.7 to 1.5. When the orientation degree β is equal to or greater than the above lower limit, the packaging film 1 has better water vapor barrier properties. When the orientation degree β is equal to or less than the above upper limit, the impact resistance of a package produced from the packaging film 1 can be further improved.
The ratio of the orientation degree α/the orientation degree β is preferably from 0.5 to 2.0, and more preferably from 0.5 to 1.5.

The orientation degree α and the orientation degree β are calculated from values measured by an infrared dichroism method.
The degree of orientation is measured by a transmission method using linearly polarized light, in which the electric field of the light oscillates only in a fixed direction, in an infrared spectrophotometer.
The measurement method is as follows: first, a BKG (background) measurement is performed with the polarizer set at an angle of 0° (the electric field is oriented vertically), then the sample is stretched in the vertical direction and the absorbance is measured (the polarization direction and the stretch axis are parallel at this time). The obtained value is taken as the absorbance "A//".
Next, the sample is rotated by 90°, and the absorbance is measured with the stretch axis of the sample perpendicular to the polarization direction. The obtained value is taken as the absorbance "A⊥".
The ratio of two absorbances, A// and A⊥, obtained with polarized light parallel and perpendicular to the stretching axis of the sample, is taken as the degree of orientation.
The measurement wave number in the infrared dichroism method is appropriately selected depending on the material of the object to be measured (see Kobayashi Yasuji, "Molecular Orientation by Infrared Dichroism Method", Polymer Journal, Vol. 15, No. 175, pp. 877-883).
The degree of orientation can be easily determined from the tensile modulus measured in accordance with JIS K7127:1999.

The water vapor permeability of the base layer 12 is preferably 4.0 g/( ^m2 ·day) or less, more preferably 2.0 g/( ^m2 ·day) or less, and even more preferably 1.0 g/( ^m2 ·day) or less. When the water vapor permeability of the base layer 12 is equal to or less than the above upper limit, the packaging film 1 has excellent water vapor barrier properties. The smaller the water vapor permeability of the base layer 12, the more preferable, and the lower limit of the water vapor permeability is preferably 0 g/( ^m2 ·day).
The water vapor permeability of the base layer 12 can be measured under test condition 1 described in Table A.1 in accordance with the test method described in the moisture sensor method of JIS K7129:2008.
The water vapor permeability of the base layer 12 can be adjusted by the material and thickness of the base layer 12, or a combination thereof.

The thickness _T12 of the base layer 12 is determined taking into consideration the material, configuration, etc., and is, for example, preferably 4.5 to 95 μm, more preferably 9.5 to 45 μm. When the thickness _T12 of the base layer 12 is equal to or greater than the above lower limit, the strength of the packaging film 1 is increased. In addition, when the thickness _T12 of the base layer 12 is equal to or greater than the above lower limit, the water vapor barrier property of the packaging film 1 is improved. When the thickness _T12 of the base layer 12 is equal to or less than the above upper limit, the flexibility of the packaging film 1 is increased, making it easier to handle.
The thickness _T12 of the base layer 12 can be measured, for example, by a thickness gauge.

(Coating Layer)
The coating layer 14 is provided on one surface of the base layer 12. The coating layer 14 contains titanium dioxide as a light-blocking inorganic material. The packaging film 1 has an excellent light-blocking property due to the inclusion of the coating layer 14.
The content of titanium dioxide is 0.5 to 5.0 g/ ^m2 per unit area of the coating layer 14, preferably 1.0 to 4.0 g/ ^m2 , and more preferably 1.5 to 3.0 g/ ^m2 . When the content of titanium dioxide is equal to or more than the lower limit, the light-shielding property of the film for packaging 1 can be further improved. When the content of titanium dioxide is equal to or less than the upper limit, the cohesive failure of the coating layer 14 is suppressed, and delamination (delamination) is easily suppressed. 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 produced by making a bag from the film for packaging 1 decreases. Therefore, when the content of titanium dioxide is equal to or less than the upper limit, the decrease in light-shielding property and the decrease in impact resistance can be suppressed.
The content of titanium dioxide in the coating layer 14 can be calculated from the content of titanium dioxide contained in the coating agent that forms the coating layer 14 and the amount of the coating agent applied.

The light-shielding inorganic substance contained in the coating layer 14 is titanium dioxide (titanium(IV) oxide). When calcium carbonate, for example, is used as the light-shielding inorganic substance, it is difficult to form a uniform coating film on one side of the base layer 12. For this reason, a coating layer using calcium carbonate as the light-shielding inorganic substance is prone to delamination, resulting in reduced light-shielding properties. In addition, when zinc oxide, for example, is used as the light-shielding inorganic substance, it is difficult to obtain sufficient scattering strength, and the light-shielding properties cannot be improved.

The average primary particle size of titanium dioxide contained in the coating layer 14 is preferably 100 to 500 nm, and more preferably 200 to 400 nm. When the average primary particle size of titanium dioxide is equal to or greater than the above lower limit, visible light is easily scattered, and light blocking properties are easily improved. When the average primary particle size of titanium dioxide is equal to or less than the above upper limit, the coating layer 14 is easily formed into a uniform coating film.
The average primary particle size of titanium dioxide can be determined, for example, by analyzing images taken using a transmission electron microscope.

The thickness _T14 of the coating layer 14 is, for example, preferably 0.5 to 5.0 μm, more preferably 1.0 to 4.0 μm, and even more preferably 1.5 to 3.0 μm. When the thickness _T14 of the coating layer 14 is equal to or greater than the above lower limit, the light blocking property of the packaging film 1 can be further improved. When the thickness _T14 of the coating layer 14 is equal to or less than the above upper limit, cohesive failure of the coating layer 14 can be further suppressed.
The thickness _T14 of the coating layer 14 can be measured, for example, by observing a cross section obtained by cutting the packaging film 1 in the thickness direction with a microscope or the like.

<Adhesive layer>
The adhesive layer 30 is provided on the surface of the coating layer 14 of the substrate 10. In other words, the adhesive layer 30 is located between the substrate 10 and the sealant material 20. The adhesive layer 30 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.
The adhesive layer 30 has oxygen absorbing properties because the isocyanate-based adhesive contains a carbon-carbon double bond. In addition, the isocyanate-based adhesive of the present embodiment contains an oxygen absorber, so that the adhesive layer 30 absorbs oxygen and can suppress the oxygen from passing through the packaging film 1. Therefore, the packaging film 1 can have improved oxygen barrier properties by having the adhesive layer 30.

The isocyanate-based adhesive of the present embodiment is a urethane-based adhesive containing a base agent and a curing agent, and a polyester polyol having a carbon-carbon double bond is a base agent and a compound having an isocyanate group is a curing agent.
The polyester polyol may be, for example, an unsaturated polyester made of a polycarboxylic acid component containing at least one aromatic dicarboxylic acid or anhydride thereof. As the aromatic dicarboxylic acid or anhydride thereof, phthalic anhydride is preferred.
Examples of the curing agent for the isocyanate-based adhesive of this embodiment include toluene diisocyanate (TDI), diphenylmethane diisocyanate (MDI), hexamethylene diisocyanate (HDI), and isophorone diisocyanate (IPDI, 3-isocyanatomethyl-3,5,5-trimethylcyclohexyl isocyanate).
As the curing agent, IPDI is preferred from the viewpoints of low environmental impact and excellent adhesive strength.

The oxygen absorber may be at least one selected from the group consisting of conjugated diene polymer cyclized products and transition metal salts.
Examples of the conjugated diene polymer cyclized product 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, and polyterpenes obtained by cyclizing these compounds, such as poly(α-pinene), poly(β-pinene), and poly(dipentene). As the conjugated diene polymer cyclized product, a polyisoprene cyclized product is preferable.

Examples of the transition metal salt include salts of transition metal elements and organic acids.
Examples of the transition metal element include iron, nickel, copper, manganese, cobalt, rhodium, titanium, chromium, vanadium, ruthenium, etc. As the transition metal element, iron, nickel, copper, manganese, and cobalt are preferable, manganese and cobalt are more preferable, and cobalt is further preferable.
Examples of the organic acid include acetic acid, stearic acid, dimethyldithiocarbamic acid, palmitic acid, 2-ethylhexanoic acid, neodecanoic acid, linoleic acid, tallic acid, oleic acid, resin acid, capric acid, naphthenic acid, etc. Preferred organic acids are stearic acid, palmitic acid, neodecanoic acid, linoleic acid, and oleic acid, and more preferred are neodecanoic acid and oleic acid.
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 even more preferably 4 to 6% by mass, relative to the total mass of the isocyanate-based adhesive. When the content of the oxygen absorber is equal to or greater than the above lower limit, the oxygen barrier properties of the packaging film 1 can be further improved. When the content of the oxygen absorber is equal to or less than the above upper limit, the adhesion between the substrate 10 and the sealant material 20 can be further improved. In addition, when the content of the oxygen absorber is equal to or less than the above upper limit, it is advantageous in terms of cost.

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

The content of unreacted isocyanate groups in the adhesive layer 30 is preferably 3 to 30 mol %, more preferably 3 to 20 mol %, and even more preferably 5 to 10 mol %, based on the content of the generated urethane groups. When the content of unreacted isocyanate groups is equal to or greater than the above lower limit, the unreacted isocyanate groups absorb water vapor, thereby further improving the water vapor barrier property of the packaging film 1. When the content of unreacted isocyanate groups is equal to or less than the above upper limit, the adhesion between the substrate 10 and the sealant material 20 is further improved, which is also advantageous in terms of cost.
The content of unreacted isocyanate groups can be measured by a Fourier transform infrared spectrophotometer (FTIR).
Specifically, infrared light is irradiated onto the packaging film 1, and a 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) to determine the ratio of the peak height of the urethane group to the peak height of the isocyanate group in the adhesive layer 30, thereby making it possible to determine the content of unreacted isocyanate groups relative to the content of urethane groups.

The isocyanate adhesive may be a one-liquid adhesive or a two-liquid adhesive. As the isocyanate adhesive, a two-liquid adhesive consisting of a base agent and a curing agent is preferable from the viewpoint of a fast curing speed and excellent adhesive strength.
The isocyanate-based adhesive may contain other components in addition to the base agent, the curing agent, and the oxygen absorber. Examples of the other components include additives and organic solvents that are generally used in adhesives. The content of the other components is preferably 0 to 20% by mass relative to the total mass of the isocyanate-based adhesive.

The thickness T ₃₀ of the adhesive layer 30 is, for example, preferably 1.5 to 5.0 μm, and more preferably 2.0 to 4.0 μm. When the thickness T ₃₀ of the adhesive layer 30 is equal to or greater than the above lower limit, the adhesion between the substrate 10 and the sealant 20 can be further improved. In addition, when the thickness T ₃₀ of the adhesive layer 30 is equal to or greater than the above lower limit, the oxygen barrier property and water vapor barrier property of the packaging film 1 can be further improved. When the thickness T ₃₀ 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 cross section obtained by cutting the packaging film 1 in the thickness direction with a microscope or the like.

<Sealant material>
The sealant material 20 is formed by forming an aluminum vapor-deposited layer 24 on one side of a sealant layer 22 made of a non-stretched polypropylene film. In other words, the sealant material 20 is an aluminum vapor-deposited non-stretched polypropylene film. The surface of the aluminum vapor-deposited layer 24 of the sealant material 20 faces one side of the substrate 10.
By using an aluminum-deposited unoriented polypropylene film as the sealant material 20, the packaging film 1 has excellent oxygen barrier properties, water vapor barrier properties, light blocking properties, and impact resistance.

The thickness _T20 of the sealant 20 is determined taking into consideration the material, configuration, etc., and is, for example, 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 20 is equal to or greater than the above lower limit, the oxygen barrier property, water vapor barrier property, and light blocking property of the packaging film 1 can be further improved. When the thickness _T20 of the sealant 20 is equal to or less than the above upper limit, the flexibility of the packaging film 1 is increased, making it easier to handle.
The thickness _T20 of the sealant material 20 can be measured, for example, by a thickness gauge.

(Sealant Layer)
The sealant layer 22 is made of a non-oriented polypropylene film. Examples of polypropylene in the non-oriented polypropylene film include homopolypropylene, a copolymer of polypropylene and polyethylene containing about 10% by mass of polyethylene, block polypropylene, etc. The sealant layer 22 may contain 50% by mass or more of polypropylene.
The unstretched polypropylene film has excellent heat sealability. Therefore, by using the unstretched polypropylene film as the sealant layer 22, the sealability when sealing the packaging film 1 can be improved. As a result, the impact resistance of the packaging body produced by making a bag using the packaging film 1 can be improved.
The sealant layer 22 may be a single layer, or may be a multi-layer in which two or more layers are laminated.

The thickness _T22 of the sealant layer 22 is determined taking into consideration the material and the like, and is, for example, 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 equal to or greater than the above lower limit, the impact resistance of the packaging film 1 can be further improved. When the thickness _T22 of the sealant layer 22 is equal to or less than the above upper limit, the flexibility of the packaging film 1 is improved, making it easier to handle.
The thickness _T22 of the sealant layer 22 can be measured, for example, by a thickness gauge.

(Aluminum vapor deposition layer)
The aluminum vapor deposition layer 24 has oxygen barrier properties, water vapor barrier properties, and light blocking properties. That is, the aluminum vapor deposition layer 24 in this embodiment plays a role in suppressing the transmission of oxygen, water vapor, ultraviolet light, and visible light.
In this embodiment, the aluminum vapor deposition layer 24 is formed on the sealant layer 22, not on the substrate 10. Therefore, by providing a printed layer on the substrate 10, a predetermined appearance can be imparted to the packaging film 1 without being blocked by the aluminum vapor deposition layer 24. As a result, the appearance of the packaging film 1 can be made beautiful.
In addition, in this embodiment, by using the aluminum vapor deposition layer 24 and the coating layer 14 in combination, the light-blocking properties of the packaging film 1 can be further improved, and deterioration of the contents of the packaging body made from the packaging film 1 due to ultraviolet rays, etc. can be suppressed.

The thickness _T24 of the aluminum vapor deposition layer 24 is 20 to 100 nm, preferably 35 to 85 nm, and more preferably 50 to 70 nm. When the thickness T24 of the aluminum vapor deposition layer ₂₄ is equal to or greater than the above lower limit, the oxygen barrier property, water vapor barrier property, and light blocking property of the packaging film 1 are more easily improved. When the thickness _T24 of the aluminum vapor deposition layer 24 is equal to or less than the above upper limit, the occurrence of delamination due to cohesive failure can be suppressed. Therefore, the decrease in impact resistance of the packaging film 1 can be suppressed. In addition, when the thickness _T24 of the aluminum vapor 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 vapor deposition layer 24 can be measured, for example, by observing a cross section obtained by cutting the packaging film 1 in the thickness direction with a microscope or the like.

<Manufacturing method of packaging film>
The manufacturing method of the packaging film 1 includes a step of obtaining a base layer 12 (base layer manufacturing step), a step of providing a coating layer 14 on the surface of the base layer 12 to obtain a substrate 10 (coating step), a step of obtaining a sealant layer 22 (sealant layer manufacturing step), a step of providing an aluminum vapor deposition layer 24 on one side of the sealant layer 22 to obtain a sealant material 20 (sealant material manufacturing step), a step of laminating the substrate 10 and the sealant material 20 with an adhesive therebetween to obtain a laminate (laminate manufacturing step), and a step of subjecting the laminate to a heat treatment (heat treatment step).

<Base layer manufacturing process>
The method for obtaining the base layer 12 in the base layer manufacturing step is selected from conventionally known methods such as an inflation method, a T-die method, and a co-extrusion method depending on the material and configuration of the base layer 12 .

<Coating process>
In the coating step, the coating layer 14 is provided on one surface of the base layer 12. The coating layer 14 is obtained by applying a coating agent containing titanium dioxide to one surface of the base layer 12 and drying it.

The coating agent includes titanium dioxide and a solvent.
The content of titanium dioxide in the coating agent is preferably 10 to 50 mass %, more preferably 15 to 40 mass %, and even more preferably 20 to 30 mass %, based on the total mass of the coating agent. When the content of titanium dioxide in the coating agent is equal to or more than the above lower limit, the light blocking properties can be further improved. When the content of titanium dioxide in the coating agent is equal to or less than the above upper limit, a stable coating film is easily formed.
Examples of the solvent contained in the coating agent include propyl acetate (normal propyl acetate), ethyl acetate, isopropyl alcohol (IPA), ethanol, butyl acetate, methyl ethyl ketone, hexane, etc. Propyl acetate, ethyl acetate, and isopropyl alcohol are preferred as the solvent contained in the coating agent because they have good compatibility with titanium dioxide.
These solvents may be used alone or in combination of two or more.

The coating agent may contain various resins in addition to titanium dioxide and a solvent. Examples of the various resins include chlorinated polypropylene (chlorinated PP), chlorinated polyolefin (chlorinated PO), nitrocellulose, etc. By containing various resins, the coating agent can further increase the stability of the coating film.
The coating agent may be used as printing ink to impart a predetermined appearance to the packaging film 1. The printing ink contains the above-mentioned various resins and pigments of various colors. When the coating agent is used as printing ink, the coating layer 14 also serves as a printing layer.

The amount of the coating agent applied in the application step is, for example, preferably 1 to 30 g/m ² , more preferably 2 to 25 g/m ² , and even more preferably 3 to 20 g/m ^2. When the amount of the coating agent applied is within the above numerical range, it is easy to control the titanium dioxide content of the coating layer 14 to a desired range.

The method for applying the coating agent to the base layer 12 is not particularly limited, and may be, for example, applied using a brush or a spray.

The temperature at which the coating agent is dried after being applied to the base layer 12 is not particularly limited, and is, for example, preferably 30 to 60° C., more preferably 35 to 50° C. When the drying temperature is equal to or higher than the above lower limit, it is easy to improve the stability of the coating film of the coating layer 14. When the drying temperature is equal to or lower than the above upper limit, it is easy to make the thickness _T14 of the coating layer 14 uniform.
The substrate 10 is obtained by providing a coating layer 14 on one side of a base layer 12 .

<Sealant layer manufacturing process>
The method for obtaining the sealant layer 22 in the sealant layer manufacturing process is selected from conventionally known methods such as an inflation method, a T-die method, and a co-extrusion method depending on the material and configuration of the sealant layer 22 .

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

<Laminate manufacturing process>
In the laminate manufacturing process, a laminate is manufactured of the substrate 10 and the sealant material 20. The method for laminating the substrate 10 and the sealant material 20 in the laminate manufacturing process is selected from conventionally known methods such as, for example, a dry lamination method.
In the dry lamination method, for example, an adhesive is applied to the surface of the aluminum vapor deposition layer 24 of the sealant material 20 to be laminated, the substrate 10 and the sealant material 20 are laminated via the adhesive, and each layer is pressure-bonded and dried to obtain a laminate. The obtained laminate is, for example, wound into a roll.
The adhesive may be applied to the coating layer 14 of the substrate 10 .

<Heat treatment step>
After the laminate is manufactured as described above, the laminate is subjected to a heat treatment in the heat treatment step, which promotes the curing of the adhesive.

The temperature of the heat treatment is, for example, preferably 30 to 60°C, and more preferably 35 to 50°C.
When the heat treatment temperature is equal to or higher than the lower limit, curing of the adhesive is sufficiently promoted, and the adhesion between the substrate 10 and the sealant material 20 can be further increased. When the heat treatment temperature is equal to or lower than the upper limit, damage to each layer constituting the laminate due to heat can be suppressed, and deterioration of the oxygen barrier property and water vapor barrier property of the packaging film 1 can be further suppressed.

The heat treatment time is, for example, preferably 5 hours or more, more preferably 5 to 96 hours, and even more preferably 12 to 48 hours. When the heat treatment time is equal to or more than the above lower limit, the curing of the adhesive is sufficiently promoted, and the adhesion between the substrate 10 and the sealant 20 can be further improved. When the heat treatment time is equal to or less than the above upper limit, the productivity of the packaging film 1 can be improved.
The heat treatment of the laminate can be carried out in a conventionally known thermostatic chamber or the like.
The laminate that has been subjected to the heat treatment can be distinguished from the laminate that has not been subjected to the heat treatment, for example, by analyzing the cured state of the adhesive of both of them by FTIR or nuclear magnetic resonance (NMR) spectroscopy.

In addition to the steps described above, the method for producing a packaging film may also include a printing step of providing a printed layer (not shown) on the substrate 10 for the purpose of imparting a predetermined appearance to the packaging film.
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 used.

≪Packaging body≫
The packaging body of the present embodiment is a bag made from the packaging film 1 of the present embodiment. An example of the packaging body is a bag made by heat-sealing the sealant layers 22 of the packaging film 1 together.
Examples of the form of the package include a palm-sealed bag, a three-side sealed bag, a four-side sealed bag, a gusseted bag, a stand-up bag, and bags with zippers of these.
Further, for example, the packaging body may be a container comprising a container body having an opening and a lid body made of the packaging film 1, in which the sealant layer 22 is abutted against the periphery of the opening of the container body, and the packaging film 1 is heat-sealed to the container body. In this case, polypropylene is preferable as the material for the container body from the viewpoint of easy recycling.

As described above, the packaging film 1 of this embodiment includes the substrate 10 having the coating layer 14 containing titanium dioxide formed on the base layer 12, and therefore has excellent water vapor barrier properties and light blocking properties.
The packaging film 1 of this embodiment includes the sealant material 20 in which the aluminum vapor deposition layer 24 is formed on the sealant layer 22, and therefore has excellent oxygen barrier properties, water vapor barrier properties, and light blocking 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 therefore has excellent oxygen absorption properties and therefore excellent oxygen barrier properties.
The packaging film 1 of the present embodiment has excellent oxygen absorbing properties because the adhesive layer 30 contains an oxygen absorbent, and therefore the packaging film 1 of the present embodiment has excellent oxygen barrier properties.
In the packaging film 1 of this embodiment, both the resin of the base material 10 and the resin of the sealant 20 are polypropylene. In this way, the packaging film 1 of this embodiment is a mono-material, and therefore can be easily recycled.
A package produced using the film for packaging 1 of this embodiment has excellent heat sealability of the sealant layer 22, and therefore can maintain its seal strength and has excellent impact resistance.
In a package produced using the packaging film 1 of this embodiment, the coating layer 14 can also serve as a printing layer, so that a desired appearance can be imparted, resulting in a beautiful appearance.
The packaging material produced using the packaging film 1 of this embodiment is a mono-material, and therefore can be easily recycled.

[Second embodiment]
<Packaging film>
A packaging film according to a second embodiment of the present invention will be described with reference to the drawings. The same components as those in the first embodiment are denoted by the same reference numerals, and the description thereof will be omitted.
2 is formed by laminating, in this order, a substrate 16, an adhesive layer 30, and a sealant 20. That is, the film 2 for packaging includes the substrate 16, the sealant 20 located on one side of the substrate 16, and the adhesive layer 30 located between the substrate 16 and the sealant 20.

The packaging film 2 of this embodiment comprises a substrate 16 which is a biaxially oriented polypropylene film, and a sealant material 20 which is located on one side of the substrate 16 and has an aluminum vapor deposition layer 24 formed on one side of a sealant layer 22 made of unoriented polypropylene film.
In the packaging film 2 of this embodiment, the resin of the base material 16 and the resin of the sealant 20 are the same type (polypropylene). Therefore, when collecting the packaging film 2 of this embodiment, it is not necessary to collect the base material 16 and the sealant 20 separately, and the packaging film 2 can be easily recycled.
The film for packaging 2 of this embodiment differs from the film for packaging 1 of the first embodiment in that the substrate does not include a coating layer.

The oxygen permeability of the packaging film 2 is similar to that of the packaging film 1 of the first embodiment.
The light transmittance of the film for packaging 2 is similar to that of the film for packaging 1 of the first embodiment.
The light transmittance of the packaging film 2 can be adjusted by the material and thickness of the substrate 16, the content of the light-shielding inorganic substance, the thickness of the aluminum vapor deposition layer 24, and a combination of these.
The thickness _T2 of the film 2 for a package is similar to the thickness _T1 of the film 1 for a package in the first embodiment.

<Base material>
The substrate 16 is a biaxially oriented polypropylene film. The substrate 16 contains polypropylene and titanium dioxide. By using a biaxially oriented polypropylene film as the substrate 16, the water vapor barrier property of the packaging film 2 can be improved. This is believed to be because the crystallinity of polypropylene can be increased by stretching the polypropylene film. Furthermore, polypropylene has superior dispersibility of titanium dioxide compared to other resins such as polyethylene terephthalate. This allows the light blocking property of the packaging film 2 to be further improved.
Examples of the polypropylene in the base material 16 include homopolypropylene, a copolymer of polypropylene and polyethylene containing about 10% by mass of polyethylene, block polypropylene, etc. The base material 16 may contain 50% by mass or more of polypropylene.
The substrate 16 may be a single layer, or may be a multi-layer in which two or more layers are laminated.

The substrate 16 contains titanium dioxide as a light-shielding inorganic material. The packaging film 2 has the substrate 16 and is therefore excellent in light-shielding properties.
The content of titanium dioxide in the substrate 16 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 more preferably 15% by mass or more and 40% by mass or less, relative to the total mass of the substrate 16. When the content of titanium dioxide is above the lower limit, the light blocking property of the packaging film 2 can be further improved. When the content of titanium dioxide is less than the upper limit, the strength of the substrate 16 can be further increased, and a decrease in the impact resistance of the packaging film 2 can be suppressed.

The light-shielding inorganic substance contained in the base material 16 is titanium dioxide. If, for example, calcium carbonate or zinc oxide is used as the light-shielding inorganic substance, it is difficult to obtain sufficient scattering strength, and the light-shielding properties cannot be improved.

The average primary particle size of the titanium dioxide contained in the substrate 16 is the same as the average primary particle size of the titanium dioxide contained in the coating layer 14 in the first embodiment.

<Manufacturing method of packaging film>
The manufacturing method of the packaging film 2 includes a step of obtaining a substrate 16 (substrate manufacturing step), a step of obtaining a sealant layer 22 (sealant layer manufacturing step), a step of providing an aluminum vapor deposition layer 24 on one side of the sealant layer 22 to obtain a sealant material 20 (sealant material manufacturing step), a step of laminating the substrate 16 and the sealant material 20 with an adhesive therebetween to obtain a laminate (laminate manufacturing step), and a step of subjecting the laminate to a heat treatment (heat treatment step).

<Base material manufacturing process>
In the substrate manufacturing process, a substrate 16 containing titanium dioxide is obtained.
The resin composition that is the raw material of the substrate 16 is molded by a conventionally known method such as an inflation method, a T-die method, a co-extrusion method, etc. At this time, the substrate 16 is obtained by molding the resin composition while stretching it in the MD direction and the TD direction.
The resin composition includes polypropylene and titanium dioxide. Examples of the polypropylene in the resin composition include homopolypropylene, a copolymer of polypropylene and polyethylene containing about 10% by mass of polyethylene, and block polypropylene. The resin composition may contain 50% by mass or more of polypropylene.

The content of titanium dioxide in the resin composition is more than 5% by mass and less than 50% by mass, preferably 10% by mass to 45% by mass, and more preferably 15% by mass to 40% by mass, based on the total mass of the resin composition. When the content of titanium dioxide is above the lower limit, the light blocking properties of the packaging film 2 can be further improved. When the content of titanium dioxide is less than the upper limit, the strength of the substrate 12 can be further increased, and a decrease in the impact resistance of the packaging film 2 can be suppressed.

The resin composition may contain other components in addition to polypropylene and titanium dioxide. Examples of other components include additives such as nucleating agents, flame retardants, and lubricants that are commonly used in polypropylene films.

The sealant layer manufacturing process, sealant material manufacturing process, laminate manufacturing process, and heat treatment process are the same as the manufacturing method of the packaging film 1 in the first embodiment.

≪Packaging body≫
The packaging body of the present embodiment is a bag made from the packaging film 2 of the present embodiment. An example of the packaging body is a bag made by heat-sealing the sealant layers 22 of the packaging film 2 to each other.
Examples of the form of the package include a palm-sealed bag, a three-side sealed bag, a four-side sealed bag, a gusseted bag, a stand-up bag, and bags with zippers of these.
Further, for example, the packaging body may be a container comprising a container body having an opening and a lid body made of a packaging film 2, in which a sealant layer 22 is abutted against the periphery of the opening of the container body, and the packaging film 2 is heat-sealed to the container body. In this case, polypropylene is preferable as the material for the container body from the viewpoint of easy recycling.

As described above, the packaging film 2 of this embodiment has excellent water vapor barrier properties and light blocking properties because it includes the substrate 16 containing titanium dioxide.
In the packaging film 2 of this embodiment, both the base material 16 and the sealant 20 are made of polypropylene resin. In this way, the packaging film 2 of this embodiment is a mono-material, and therefore can be easily recycled.
A package produced by making a bag using the film for packaging 2 of this embodiment may have a printed layer on the base material 16. This allows a desired appearance to be imparted, making the appearance beautiful.
The packaging material produced using the packaging film 2 of this embodiment is a mono-material, and therefore can be easily recycled.

[Other embodiments]
In the first embodiment described above, the coating layer 14 is formed on the surface of the base layer 12 facing the sealant material 20, but the present invention is not limited to this, and the coating layer may be formed on the surface of the base layer opposite to the surface facing the sealant material. However, from the viewpoint of suppressing adhesion of dirt to the surface of the substrate, it is preferable that the coating layer is formed on the surface of the base layer facing the sealant material.
In the first embodiment described above, the coating layer 14 is formed on one side of the base layer 12, but the present invention is not limited to this, and the coating layer may be formed on both sides of the base layer.
In the above-described second embodiment, the substrate 16 does not include a coating layer, but the present invention is not limited to this, and the substrate 16 may be used in combination with a coating layer.

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≫
OPP: biaxially oriented polypropylene film, Pylen (registered trademark) Film-OT (product name), manufactured by Toyobo Co., Ltd., thickness 30 μm.
OPP: biaxially oriented polypropylene film, Pylen (registered trademark) Film-OT (product name), manufactured by Toyobo Co., Ltd., thickness 20 μm.
PET: polyethylene terephthalate film, Toyobo Ester Film (product name), manufactured by Toyobo Co., Ltd., thickness 38 μm.

<Coating layer>
<Light-shielding inorganic substance>
TiO ₂ : Titanium dioxide, Titanium Oxide (product name), manufactured by Sakai Chemical Industry Co., Ltd., average primary particle size (average particle size of 100 primary particles) 200 nm.
CaCO ₃ : Calcium carbonate, Neolite (product name), manufactured by Takehara Chemical Industry Co., Ltd., average primary particle size (average particle size of 100 primary particles) 80 nm.
ZnO: zinc oxide, type 1 (product name), manufactured by Sakai Chemical Industry Co., Ltd., average primary particle size (average particle size of 100 primary particles) 750 nm.

<Coating Agent>
(solvent)
Solvent A: Propyl acetate, manufactured by Sankyo Chemical Co., Ltd.
Solvent B: ethyl acetate, manufactured by Sankyo Chemical Co., Ltd.
Solvent C: isopropyl alcohol, manufactured by Sankyo Chemical Co., Ltd.
(resin)
Resin a: Chlorinated PP, Hardlen (registered trademark) (product name), manufactured by Toyobo Co., Ltd.
Resin b: chlorinated PO, Superchlorine (registered trademark) (product name), manufactured by Nippon Paper Industries Co., Ltd.
Resin c: Nitrocellulose, industrial nitrocellulose (product name), manufactured by Taihei Chemical Products Co., Ltd.
(Coating agents used in each example)
Example 1: A liquid prepared by mixing solvent D (a mixture of equal amounts of solvents A, B, and C) with 30% by mass of titanium dioxide.
Example 2: A liquid in which solvent D was mixed with 15% by mass of titanium dioxide.
Examples 3 to 6: A liquid in which solvent D, resin a, and titanium dioxide were mixed in a mass ratio of 6:2:2.
Example 7: A liquid obtained by mixing solvent D, resin b, and titanium dioxide in a mass ratio of 6:2:2.
Example 8: A liquid obtained by mixing solvent D, resin c, and titanium dioxide in a mass ratio of 6:2:2.
Comparative Example 1: A liquid in which solvent D, resin a, and calcium carbonate were mixed in a mass ratio of 6:2:2.
Comparative Example 2: A liquid in which solvent D, resin a, and zinc oxide were mixed in a mass ratio of 6:2:2.
Comparative Example 3: A liquid in which solvent D was mixed with 7% by mass of titanium dioxide.
Comparative Example 4: A liquid in which solvent D was mixed with 90% by mass of titanium dioxide.
Comparative Examples 5 to 7: Liquids in which solvent D, resin a, and titanium dioxide were mixed in a mass ratio of 6:2:2.

<Sealant material>
<Sealant Layer>
CPP: Non-oriented polypropylene film, Taiko (registered trademark) FC, manufactured by Futamura Chemical Co., Ltd., thickness 30 μm.
CPP: Unstretched polypropylene film, Pylen (registered trademark) Film-CT (product name), manufactured by Toyobo Co., Ltd., thickness 20 μm.
<Aluminum vapor deposition layer>
(Deposition conditions)
- Name of deposition equipment: Roll-type vacuum deposition equipment EWA series (product name), manufactured by ULVAC, Inc.
- Vapor deposition source: aluminum.
Vacuum level in deposition chamber: 0.2 Pa.
Film conveying speed: 200 m/min.

≪Adhesive layer≫
<Main ingredient>
- Saturated polyester: manufactured by Nippon Synthetic Chemical Industry 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: conjugated diene polymer cyclized product (polyisoprene cyclized product).
Transition metals: transition metal salts, cobalt neodecanoate, manufactured by Nippon Chemical Industries Co., Ltd.

[Examples 1 to 8, Comparative Examples 1 to 7]
The coating agent of each example was sprayed onto one side of the base layer shown in Table 1, and dried at 80°C for 1 hour to form a coating layer with the thickness shown in Table 1 to obtain a substrate. An adhesive containing an oxygen absorber shown in Table 1 was applied to the aluminum vapor-deposited layer of the sealant material having the aluminum vapor-deposited layer with the thickness shown in Table 1, and the surface of the substrate on which the coating layer had been formed was laminated to obtain a laminate. This laminate was heat-treated at 40°C for 72 hours to produce packaging films according to the configurations of Examples 1 to 8 and Comparative Examples 1 to 7. In the table, "-" indicates that no oxygen absorber was included.

[Examples 9 to 10, Comparative Examples 8 to 11]
An adhesive containing an oxygen absorber shown in Table 3 was applied to the aluminum vapor deposition layer of the sealant material having a thickness of 60 nm, and a substrate shown in Table 3 was laminated thereon to obtain a laminate. This laminate was subjected to a heat treatment at 40° C. for 72 hours to produce packaging films according to the configurations of Examples 9 to 10 and Comparative Examples 8 to 11.

[Evaluation method]
<Evaluation of oxygen barrier properties>
For the packaging films obtained in each example, the oxygen permeability was measured according to the test method for oxygen gas permeability using an electrolytic sensor method described in Appendix A of JIS K7126-2:2006, and the oxygen barrier property was evaluated based on the following evaluation criteria. The results are shown in Tables 2 and 4.
Evaluation Criteria
◎: Oxygen permeability is 2.0 mL/(m ² ·day) or less.
○: Oxygen permeability is more than 2.0 mL/(m ² ·day) and less than 4.0 mL/(m ² ·day).
×: Oxygen permeability exceeds 4.0 mL/(m ² ·day).

<Evaluation of Water Vapor Barrier Property>
For the substrates of each example, the water vapor permeability was measured under the test condition 1 described in Table A.1 in accordance with the test method described in the moisture sensor method of JIS K7129:2008, and the water vapor barrier property was evaluated based on the following evaluation criteria. The results are shown in Tables 2 and 4.
Evaluation Criteria
◎: Water vapor permeability of 2.0 g/(m ² ·day) or less.
○: Water vapor permeability exceeding 2.0 g/(m ² ·day) and not more than 4.0 g/(m ² ·day).
×: Water vapor permeability exceeding 4.0 g/(m ² ·day).

<Evaluation of Light Blocking Property>
The light transmittance of the packaging film obtained in each example was measured for visible light with a wavelength of 450 nm using an ultraviolet-visible spectrophotometer (Shimadzu Corporation, UV-2600i), and the light-shielding ability was evaluated based on the following evaluation criteria. The results are shown in Tables 2 and 4.
Evaluation Criteria
◎: Light transmittance 4% or less.
○: Light transmittance of more than 4% and less than 10%.
△: Light transmittance of more than 10% and less than 20%.
×: Light transmittance exceeding 20%.

<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/ ^cm2 , sealing width: 10 mm) to prepare a 130 mm x 170 mm three-sided sealed bag (flat bag). 180 mL of water was filled into this flat bag, and the opening was heat sealed under the same conditions as above to prepare an evaluation sample. This evaluation sample was dropped vertically onto a concrete surface from a height of 1.2 m, and this operation was repeated three times (drop strength test). Of the 10 evaluation samples, the number of samples in which leakage of the contents was observed (number of broken bags) was counted, and the impact resistance was evaluated based on the following evaluation criteria. The results are shown in Tables 2 and 4.
Evaluation Criteria
◎: 0 broken bags.
○: 1 or 2 broken bags.
×: 3 or more broken bags.

<Overall evaluation>
Based on the results of the oxygen barrier property evaluation, water vapor barrier property evaluation, light blocking property evaluation, and impact resistance evaluation, each example of the packaging film was comprehensively evaluated according to the following evaluation criteria. The results are shown in Tables 2 and 4. Films with a comprehensive evaluation of "◎" or "◯" were deemed to have passed.
Evaluation Criteria
◎: All evaluation results are “◎”.
○: The evaluation result includes one or more “○” marks and no “×” marks.
×: The evaluation result contains one or more "×".

As shown in Tables 1 to 4, the packaging films and packages of Examples 1 to 10 to which the present invention was applied were overall rated as "◎" or "◯," and it was confirmed that they had excellent oxygen barrier property, water vapor barrier property, light blocking property, and impact resistance.
On the other hand, Comparative Examples 1 and 2, which do not contain titanium dioxide in the coating layer, had a high light transmittance and were rated as "x" for light shielding. Comparative Examples 3 and 4, in which the content of titanium dioxide is outside the range of the present invention, had a high light transmittance and were rated as "x" for light shielding. Comparative Example 5, in which no oxygen absorber is contained in the adhesive layer, had a high oxygen transmittance and were rated as "x" for oxygen barrier properties. In addition, the number of broken bags was high and the impact resistance was rated as "x". Comparative Example 6, in which PET was used for the base layer, had a high water vapor transmittance and were rated as "x" for water vapor barrier properties. In addition, the light transmittance was high and the light shielding was rated as "x". Comparative Example 7, in which the film thickness of the aluminum vapor deposition layer was outside the range of the present invention, had a high number of broken bags and were rated as "x" for impact resistance. Comparative Example 8, in which the content of titanium dioxide is outside the range of the present invention, had a high light transmittance and were rated as "x" for light shielding. Comparative Examples 9 and 10, which did not contain titanium dioxide in the substrate, had high light transmittance and were rated as "x" in light blocking properties. Comparative Example 11, which used PET in the substrate, had high water vapor permeability and was rated as "x" in water vapor barrier properties. In addition, the light transmittance was high and the light blocking properties were rated as "x".

These results confirm that the application of the present invention provides excellent oxygen barrier properties, water vapor barrier properties, light blocking properties, and impact resistance.

1, 2 Packaging film 10, 16 Substrate 12 Base layer 14 Coating layer 20 Sealant material 22 Sealant layer 24 Aluminum vapor deposition layer 30 Adhesive layer

Claims (8)

A substrate having a coating layer containing titanium dioxide of 0.5 to 5.0 g/ ^m2 formed on the surface of a base layer made of a biaxially oriented polypropylene film;
a sealant material located on one surface of the base material, the sealant material having an aluminum vapor deposition layer formed on one surface of a sealant layer made of a non-oriented polypropylene film;
an adhesive layer located between the substrate and the sealant material;
the aluminum vapor deposition layer faces the base material,
The thickness of the aluminum vapor deposition layer is 20 to 100 nm,
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,
The isocyanate-based adhesive contains an oxygen absorber,
A packaging film, wherein the content of the oxygen absorber is 1 mass % or more based on the total mass of the isocyanate-based adhesive. A substrate which is a biaxially oriented polypropylene film;
a sealant material located on one surface of the base material, the sealant material having an aluminum vapor deposition layer formed on one surface of a sealant layer made of a non-oriented polypropylene film;
an adhesive layer located between the substrate and the sealant material;
The substrate contains titanium dioxide,
The content of the titanium dioxide is more than 5% by mass and less than 50% by mass with respect to the total mass of the substrate,
the aluminum vapor deposition layer faces the base material,
The thickness of the aluminum vapor deposition layer is 20 to 100 nm,
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,
The isocyanate-based adhesive contains an oxygen absorber,
A packaging film, wherein the content of the oxygen absorber is 1 mass % or more based on the total mass of the isocyanate-based adhesive. The packaging film according to claim 1 , wherein the coating layer faces a surface of the aluminum vapor deposition layer. 2. The packaging film according to claim 1, wherein the coating layer has a thickness of 0.5 to 5.0 μm. The film for packaging according to any one of claims 1 to 4, wherein the content of the oxygen absorber is 1 to 10 mass % based on the total mass of the isocyanate-based adhesive. The packaging film according to any one of claims 1 to 5, wherein the titanium dioxide has an average primary particle size of 100 to 500 nm. The packaging film according to any one of claims 1 to 6, wherein the oxygen absorber is at least one member selected from the group consisting of a conjugated diene polymer cyclized product and a transition metal salt. A packaging body produced by using the packaging film according to any one of claims 1 to 7 .

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