JP2023119675A - Barrier film, packaging film, packaging container, and packaging product - Google Patents

Abstract

To provide a barrier film which can suppress lowering of a barrier property while reducing environmental loads, a packaging film, a packaging container, and a packaging product.SOLUTION: A barrier film includes a base material layer and an inorganic layer, wherein the base material layer is composed of a resin containing biopolypropylene, and a resin composition containing inorganic particles. The barrier film has at least the inorganic layer formed on the base material layer, the base material layer is obtained by reaction of a raw material containing biopropylene in the presence of the inorganic particles, and the inorganic particles may contain at least one of metal and a metal oxide.SELECTED DRAWING: Figure 1

Description

The present disclosure relates to barrier films, packaging films, packaging containers and packaging products.

In packaging containers such as packaging bags used for packaging food, pharmaceuticals, etc., it is necessary to suppress deterioration and putrefaction of the contents, and to maintain the functions and properties of the contents, it is necessary to prevent moisture, oxygen, and other contents from deteriorating. It is required to have a gas barrier property to block the intrusion of the gas that causes it. Therefore, conventionally, barrier films are used in these packaging containers. A barrier film generally includes a substrate layer, an inorganic layer, and a gas barrier coating layer, and a polypropylene film is sometimes used as the substrate layer. For example, Patent Document 1 below discloses a transparent laminate obtained by laminating a thin film layer made of an inorganic compound and a gas barrier coating in this order on a substrate made of a transparent polypropylene film or the like.

JP-A-10-264292

By the way, in recent years, plastic polymers using biomass-derived raw materials have been attracting attention as plastic polymers with low environmental impact, and as for polypropylene, the use of biomass-derived polypropylene (bio-polypropylene) is being studied.

However, in the transparent laminate described in Patent Document 1, when bio-polypropylene is used for the polypropylene of the base material layer, it is possible to reduce the environmental load, but there is room for improvement in terms of suppressing the deterioration of barrier properties. had

The present disclosure has been made in view of the above problems, and aims to provide a barrier film, a packaging film, a packaging container, and a packaging product that can suppress deterioration of barrier properties while reducing environmental load. do.

The present inventors have investigated the cause of the above problems. First, the present inventors have noticed that bio-polypropylene tends to increase the amount of low-molecular-weight components when the propylene in the base material layer is replaced by bio-polypropylene. Therefore, this low molecular weight component bleeds out to the surface of the base material layer and appears on the surface, and the inorganic layer peels off from the base material layer due to this low molecular weight component, resulting in a decrease in barrier properties. The inventors thought As a result of further studies, the inventors of the present invention have found that the above problems can be solved by the following inventions.

That is, one aspect of the present disclosure is a barrier film comprising a substrate layer and an inorganic layer, wherein the substrate layer is a barrier film made of a resin composition containing a resin containing bio-polypropylene and inorganic particles. be.

According to the barrier film of the present disclosure, when the base material layer contains the low-molecular-weight component of bio-polypropylene, the low-molecular-weight component reaches the surface of the base material layer due to the inclusion of inorganic particles in the base material layer. It becomes necessary to avoid inorganic particles before passing. Therefore, the low-molecular-weight component bleeds out and takes a long path to reach the surface of the substrate layer. As a result, low-molecular-weight components are less likely to appear on the surface of the base material layer, the inorganic layer is less likely to separate from the base material layer, the formation of gaps between the inorganic layer and the base material layer is suppressed, and barrier properties are reduced. is suppressed. The barrier film also includes bio-polypropylene in the base layer. Therefore, according to the barrier film of the present disclosure, deterioration of barrier properties can be suppressed while reducing environmental load.

The barrier film is formed by forming at least the inorganic layer on the substrate layer, and the substrate layer is obtained by reacting a raw material containing biopropylene in the presence of the inorganic particles. , the inorganic particles preferably contain at least one of a metal and a metal oxide.

なお、金属に代えて金属酸化物が用いられる場合、金属酸化物は、酸素を介在した電子移動により、金属と同様に作用すると考えられる。 In this case, when the inorganic particles are at least one of metals and metal oxides, the metals and metal oxides are better catalysts than acid or base catalysts in the reaction to form bio-polypropylene from raw materials comprising bio-propylene. Acts as, promotes high molecular weight bio-polypropylene. Therefore, when raw materials containing biopropylene are reacted in the presence of inorganic particles, the reaction is effectively carried out and the amount of low molecular weight components of biopolypropylene is reduced. That is, the amount of low-molecular-weight components appearing on the surface of the substrate layer due to bleeding out is reduced. As a result, the inorganic layer is easily formed on the substrate layer, a dense inorganic layer is formed, and the deterioration of the barrier properties is further suppressed.
For example, when the inorganic particles are metal, first, as shown in the following formula (1), two biopropylenes (first propylene) having double bonds are adsorbed to the metal (Metal), and then, Electron transfer to the double bond of the first propylene combines the metal and the first propylene to form a conjugate. At this time, the metal in the bond is in a state where free electrons work and the reaction easily proceeds. Next, as shown in the following formula (2), when another biopropylene (second propylene) approaches the combined body, the bond between the metal and the first propylene is cut, and then the second propylene adsorbs to the metal. As a result, electrons move from the metal to the second propylene, and the first propylene with the broken bond bonds to the second propylene. In this way, as shown in the following formula (3), a new conjugate is formed in which the second propylene is bonded to the conjugate to form a high-molecular-weight bio-polypropylene. In the following (1) to (3), for biopropylene, only the portion having a double bond (-C=C-) is shown before bonding, and after bonding, the double bond is changed to a single bond. is shown.

In addition, when a metal oxide is used instead of a metal, it is considered that the metal oxide acts in the same manner as a metal due to electron transfer mediated by oxygen.

In the barrier film, the inorganic particles preferably contain the metal oxide.

In this case, it is possible to effectively suppress the deterioration of the barrier properties of the barrier film.

In the barrier film, the metal oxide is preferably zeolite.

In this case, deterioration of the barrier properties can be more effectively suppressed as compared with the case where the metal oxide is a metal oxide other than zeolite.

In the above barrier film, it is preferable that the base material layer has a biomass degree of 50% or more.

In this case, compared with the case where the biomass degree of the base material layer is less than 50%, the deterioration of the barrier properties can be suppressed more effectively.

Preferably, the barrier film further includes an anchor coat layer between the base material layer and the inorganic layer, and the anchor coat layer contains an organic material.

In this case, the adhesion between the substrate layer and the inorganic layer is further improved by the anchor coat layer.

Preferably, the barrier film further comprises a gas barrier coating layer that covers the inorganic layer, and the gas barrier coating layer contains Si and C.

In this case, since the gas-barrier coating layer contains Si, the adhesion between the gas-barrier coating layer and the inorganic layer is further improved, and since the gas-barrier coating layer contains C, the flexibility of the gas-barrier coating layer is improved. In addition, cracks can be suppressed even when excessive bending stress is applied to the barrier film.

Another aspect of the present disclosure is a packaging film including the barrier film described above and a sealant layer provided on the inorganic layer side of the barrier film.

Since this packaging film has the above-described barrier film, it is possible to suppress deterioration of barrier properties while reducing environmental load.

Yet another aspect of the present disclosure is a packaging container obtained using the packaging film described above.

Since this packaging container is obtained using the packaging film described above, it is possible to suppress deterioration of the barrier property while reducing the environmental load. Therefore, even if the contents are enclosed in the packaging container, deterioration of the quality of the contents can be suppressed for a long period of time.

Another aspect of the present disclosure is a packaged product comprising the packaging container described above and a content enclosed in the packaging container.

Since this packaged product is obtained using the packaging container described above, it is possible to suppress deterioration of the barrier property while reducing the environmental load. Therefore, according to the packaging product of the present disclosure, deterioration of the quality of the contents can be suppressed over a long period of time.

According to the present disclosure, a barrier film, a packaging film, a packaging container, and a packaging product are provided that can suppress deterioration of barrier properties while reducing environmental load.

1 is a cross-sectional view of one embodiment of a barrier film of the present disclosure; FIG. 1 is a cross-sectional view showing one embodiment of a packaging film of the present disclosure; FIG. 1 is a side view of one embodiment of a packaged product of the present disclosure; FIG.

Hereinafter, embodiments of the present disclosure will be described in detail.

<Barrier film>
First, one embodiment of the barrier film of the present disclosure will be described with reference to FIG. FIG. 1 is a cross-sectional view showing one embodiment of the barrier film of the present disclosure. As shown in FIG. 1, the barrier film 10 includes a substrate layer 1, an inorganic layer 3, and a gas barrier coating layer 4 in this order. Here, the substrate layer 1 is made of a resin composition containing a bio-polypropylene-containing resin and inorganic particles. In addition, the barrier film 10 may further have an anchor coat layer 2 between the base layer 1 and the inorganic layer 3 .

According to this barrier film 10, when the base material layer 1 contains low-molecular weight components of bio-polypropylene, the inorganic particles are contained in the base material layer 1, so that the low-molecular-weight components are present on the surface of the base material layer 1. It becomes necessary to avoid inorganic particles before reaching . Therefore, the low-molecular-weight component bleeds out to reach the surface of the substrate layer 1, and the path length becomes longer. As a result, the low-molecular-weight components are less likely to appear on the surface of the substrate layer 1, the inorganic layer 3 is less likely to separate from the substrate layer 1, and the formation of a gap between the inorganic layer 3 and the substrate layer 1 is suppressed. , a decrease in barrier properties is suppressed. Also, the barrier film 10 contains bio-polypropylene in the base material layer 1 . Therefore, according to the barrier film 10, it is possible to suppress the deterioration of the barrier property while reducing the environmental load.

The base material layer 1, the anchor coat layer 2, the inorganic layer 3 and the gas barrier coating layer 4 are described in detail below.

(Base material layer)
The base material layer 1 is a layer that serves as a support for the anchor coat layer 2, the inorganic layer 3, and the gas barrier coating layer 4, and is made of a resin composition containing a bio-polypropylene-containing resin and inorganic particles.

Bio-propylene may be a homopolymer of bio-propylene or a copolymer of bio-propylene and other polymerizable monomers. Other polymerizable monomers may be biomass-derived or petroleum-derived monomers. Bio-polypropylene can be obtained by polymerizing raw materials containing bio-propylene. Biopropylene can be obtained, for example, by reacting at least one of bioethanol and bioethylene as raw materials. Bioethanol can be obtained by using biomass-derived polysaccharides (for example, corn and sugar cane) as a raw material and fermenting this raw material. Bioethylene can be obtained by dehydrating bioethanol.

The resin may further contain a resin other than bio-polypropylene, if necessary. Examples of such resins include petroleum-derived polypropylene and olefins such as polyethylene. Olefins may be petroleum-derived or biomass-derived.

The inorganic particles are not particularly limited as long as they are composed of inorganic substances, and examples of the inorganic particles include metals, metal oxides, silica, and glass. These can be used individually or in mixture of 2 or more types, respectively. The reason why the inorganic particles are used is to prevent passage of low-molecular-weight components of the bio-polypropylene.

However, the inorganic particles preferably contain metal oxides. In this case, in the barrier film 10, deterioration of barrier properties can be effectively suppressed.

The metal is not particularly limited and may be a transition metal, a non-transition metal, or a mixture thereof, but preferably contains a transition metal. Examples of transition metals include nickel, platinum, and silver. These can be used individually or in mixture of 2 or more types, respectively. Zinc etc. are mentioned as a non-transition metal.

In the metal oxide, metals similar to the above metals can be used. Metal oxides include nickel oxide, zinc oxide, manganese dioxide, alumina, zeolite and iridium nitrate. These can be used individually or in mixture of 2 or more types, respectively. Among them, the metal oxide is preferably zeolite. In this case, deterioration of the barrier properties can be more effectively suppressed as compared with the case where the metal oxide is a metal oxide other than zeolite.

The inorganic particles may further contain phosphorus and potassium as needed.

Although the average particle size of the inorganic particles is not particularly limited, it is preferably 0.005 to 1000 μm. In this case, compared to the case where the average particle diameter of the inorganic particles is less than 0.005 μm, the low-molecular-weight component bleeds out and has a longer path length to reach the surface of the substrate layer, resulting in a decrease in barrier properties. can be effectively suppressed. In addition, when the average particle diameter of the inorganic particles is within the above range, the smoothness of the surface of the substrate layer 1 is further improved and the thickness of the inorganic layer 3 is improved as compared with the case where the average particle diameter of the inorganic particles exceeds 1000 μm. Since the uniformity of the thickness is further improved, the uniformity of the barrier properties of the inorganic layer 3 is further improved.

The amount of the inorganic particles is not particularly limited, but is preferably 0.01 parts by mass or more, more preferably 0.05 parts by mass or more, and particularly preferably 0.1 parts by mass with respect to 100 parts by mass of the resin. Department or above. In this case, compared with the case where the amount of the inorganic particles is less than 0.01 parts by mass with respect to 100 parts by mass of the resin, it is possible to effectively suppress the deterioration of the barrier properties. However, the amount of the inorganic particles to be blended is preferably 1 part by mass or less, more preferably 0.5 parts by mass or less with respect to 100 parts by mass of the resin. In this case, compared to the case where the amount of the inorganic particles exceeds 1 part by mass with respect to 100 parts by mass of the resin, the amount of the inorganic particles is less. is more suppressed.

Although the biomass degree of the base layer 1 is not particularly limited, it is preferably 50% or more, more preferably 70% or more. When the biomass degree of the base material layer 1 is 50% or more, the deterioration of the barrier properties of the barrier film 10 can be suppressed more effectively than when the biomass degree of the base material layer 1 is less than 50%. can. However, from the viewpoint of further suppressing deterioration of the barrier properties of the barrier film 10, it is preferably 98% or less, more preferably 95% or less.

The “biomass degree” is the biomass-derived carbon concentration in the biomass polypropylene film, and is a value obtained by measuring the biomass-derived carbon content by radiocarbon (C ¹⁴ ) measurement. By measuring the ratio of ^C14 contained in the total carbon atoms in the substrate layer 1, the ratio of biomass-derived carbon can be calculated. In the present disclosure, the degree of biomass when the content of ^C14 in the substrate layer 1 is A can be calculated based on the following formula.
Biomass degree (%) = A/105.5 x 100

The resin composition may further contain ethylene, butene, etc. when obtaining a copolymer or terpolymer. In addition, if necessary, the resin composition may contain a tackifier, a heat stabilizer, a weather stabilizer, an antioxidant, an ultraviolet absorber, a lubricant, a slip agent, a nucleating agent, an antiblocking agent, an antistatic agent, an antistatic agent, Various additives such as clouding agents, pigments, dyes, inorganic or organic fillers, etc. may be further included as long as the objects of the present disclosure are not impaired.

The substrate layer 1 may be a stretched film or a non-stretched film, but is preferably a stretched film from the viewpoint of gas barrier properties. Here, the stretched film includes a uniaxially stretched film and a biaxially stretched film, but the biaxially stretched film is preferable because it improves heat resistance.

The thickness of the base material layer 1 is not particularly limited, but may be, for example, 0.1 mm or less. Above all, the thickness of the substrate layer 1 is preferably 40 μm or less, more preferably 35 μm or less, and particularly preferably 30 μm or less. When the thickness of the base material layer 1 is 40 μm or less, the flexibility of the barrier film 10 is further improved and the oxygen gas barrier property of the barrier film 10 is further improved as compared with the case where the thickness of the base material layer 1 is more than 40 μm. be able to. However, from the viewpoint of improving the strength, the thickness is preferably 10 μm or more, more preferably 12 μm or more.

(Anchor coat layer)
The anchor coat layer 2 is a layer for further improving adhesion between the substrate layer 1 and the inorganic layer 3 , and is provided between the substrate layer 1 and the inorganic layer 3 .

The material constituting the anchor coat layer 2 is not particularly limited as long as it can improve the adhesion between the base material layer 1 and the inorganic layer 3, but such materials include organic substances. preferably included. In this case, the adhesion between the substrate layer 1 and the inorganic layer 3 is further improved by the anchor coat layer 2 . Examples of organic materials include polyester resins, polyamide resins, polyurethane resins (polyester urethane, acrylic urethane, resins obtained by reacting polyols and isocyanates), epoxy resins, phenol resins, (meth)acrylic resins, polyvinyl acetate resins, ethylene- Examples thereof include vinyl alcohol copolymers, polyolefin resins such as polyethylene or polypropylene, and resins such as cellulose resins. These may be used alone or in combination of two or more.

The anchor coat layer 2 may contain Si. In this case, the anchor coat layer 2 can be obtained, for example, by curing a resin composition containing the above resin and a silane coupling agent.

The thickness of the anchor coat layer 2 is not particularly limited as long as it can improve the adhesion between the substrate layer 1 and the inorganic layer 3, but is preferably 30 nm or more. In this case, compared to the case where the thickness of the anchor coat layer 2 is less than 30 nm, it is possible to improve the smoothness of the surface of the anchor coat layer 2 more than the surface of the base material layer 1, and the thickness of the inorganic layer 3 can be made more uniform, and the gas barrier property can be further improved. Therefore, the gas barrier properties of the barrier film 10 can be further improved. The thickness of the anchor coat layer 2 is more preferably 40 nm or more, and even more preferably 50 nm or more. By increasing the thickness of the anchor coat layer 2, it is possible to further suppress the deterioration of the water vapor barrier properties when an external force such as stretching is applied. The thickness of the anchor coat layer 2 is preferably 300 nm or less. In this case, the flexibility of the barrier film 10 is further improved as compared with the case where the thickness of the anchor coat layer 2 is 300 nm or more. More preferably, the thickness of the anchor coat layer 2 is 200 μm or less.

(Inorganic layer)
The inorganic layer 3 is a barrier layer containing an inorganic substance. By having the inorganic layer 3 , the barrier film 10 can further improve gas barrier properties while suppressing the thickness of the barrier film 10 .

Inorganics include metals, metal oxides, metal nitrides and metal oxynitrides. Metals include metal aluminum (Al) and the like, and metal oxides include silicon oxide (SiOx), aluminum oxide ( _AlOx ), and the like. Examples of metal nitrides include silicon nitride (SiN), and examples of metal oxynitrides include silicon oxynitride (SiON).
From the viewpoint of transparency and barrier properties, the constituent material of the inorganic layer 3 is preferably aluminum oxide or silicon oxide. In addition, it is particularly preferable that the constituent material of the inorganic layer 3 is silicon oxide because it has excellent tensile stretchability during processing.
When a silicon oxide film is used as the inorganic layer 3, the O/Si ratio (molar ratio) is preferably 1.2 to 1.9 from the viewpoint of gas barrier properties.

The inorganic layer 3 may consist of a single layer, or may consist of multiple layers.

Although the thickness of the inorganic layer 3 is not particularly limited, it is preferably 5 nm or more. In this case, the gas barrier properties of the barrier film 10 are further improved as compared with the case where the thickness of the inorganic layer 3 is less than 5 nm. The thickness of the inorganic layer 3 is more preferably 10 nm or more, particularly preferably 20 nm or more.

Moreover, the thickness of the inorganic layer 3 is preferably 100 nm or less. In this case, compared with the case where the thickness of the inorganic layer 3 exceeds 100 nm, the occurrence of cracks due to deformation due to internal stress of the inorganic layer 3 is suppressed, and deterioration of the gas barrier property is easily suppressed. In addition, the amount of material used can be suppressed, and the cost can be easily reduced due to the shortening of the film formation time and the like. From the viewpoint of cost reduction, the thickness of the inorganic layer 3 is more preferably 50 nm or less, and particularly preferably 40 nm or less.

(Gas barrier coating layer)
The gas-barrier coating layer 4 is composed of a cured composition for forming a gas-barrier coating layer.

The gas barrier coating layer 4 preferably contains Si and C.

In this case, since the gas barrier coating layer 4 contains Si, the adhesion between the gas barrier coating layer 4 and the inorganic layer 3 is further improved. The flexibility of the barrier film 10 is improved, and even if excessive bending stress is applied to the barrier film 10, cracks can be suppressed.

Whether the gas barrier coating layer 4 contains Si and C depends on whether Si and C are detected on the surface of the gas barrier coating layer 4 by, for example, X-ray photoelectron spectroscopy (hereinafter also referred to as "XPS"). can be confirmed.
Specifically, in XPS, it is possible to confirm whether or not Si and C are detected by performing narrow analysis under the following measurement conditions using the following measurement equipment and obtaining a spectrum.
<Measuring equipment>
JPS-9030 type photoelectron spectrometer manufactured by JEOL Ltd. <Measurement conditions>
(spectrum acquisition conditions)
Incident X-ray: MgKα (monochromatic X-ray, hν=1253.6 eV)
X-ray output: 10W (10kV/10mA)
X-ray scanning area (measurement area): circular area with a diameter of 6 mm Photoelectron capture angle: 90°

Specifically, the gas-barrier coating layer 4 mainly contains a polyvinyl alcohol-based resin and a silane compound.

The polyvinyl alcohol-based resin may have a vinyl alcohol unit obtained by saponifying a vinyl ester unit. Examples of the polyvinyl alcohol-based resin include polyvinyl alcohol (PVA), ethylene-vinyl alcohol copolymer (EVOH ). From the viewpoint of versatility, solubility, etc., PVA can be preferably used.

As PVA, for example, vinyl esters such as vinyl acetate, vinyl formate, vinyl propionate, vinyl valerate, vinyl caprate, vinyl laurate, vinyl stearate, vinyl pivalate, and vinyl versatate are polymerized alone. , saponified resins can be used.

The PVA may be a copolymerized modified PVA or a post-modified modified PVA. Copolymerized modified PVA can be obtained, for example, by copolymerizing a vinyl ester and an unsaturated monomer copolymerizable with the vinyl ester, followed by saponification. The post-modified modified PVA is obtained by copolymerizing a PVA obtained by saponifying after polymerizing a vinyl ester with an unsaturated monomer in the presence of a polymerization catalyst. The amount of modification in the modified PVA may be less than 50 mol % from the viewpoint of developing sufficient gas barrier properties, and may be 10 mol % or more from the viewpoint of obtaining the effect of modification.

Examples of the unsaturated monomers include olefins such as ethylene, propylene, isobutylene, α-octene, α-dodecene and α-octadecene; hydroxy group-containing α-olefins such as 1-ol; unsaturated acids such as acrylic acid, methacrylic acid, crotonic acid, maleic acid, maleic anhydride, itaconic acid and undecylenic acid; nitriles such as acrylonitrile and methacrylonitrile; diacetone acrylamide , acrylamide, amides such as methacrylamide; olefin sulfonic acids such as ethylenesulfonic acid, allylsulfonic acid, methallylsulfonic acid; alkyl vinyl ether, dimethyl allyl vinyl ketone, N-vinyl pyrrolidone, vinyl chloride, vinyl ethylene carbonate, -Vinyl compounds such as dialkyl-4-vinyl-1,3-dioxolane, glycerin monoallyl ether, 3,4-diacetoxy-1-butene; vinylidene chloride, 1,4-diacetoxy-2-butene, vinylene carbonate, polyoxy Propylene, polyoxypropylene vinylamine and the like can be mentioned. From the viewpoint of gas barrier properties, the unsaturated monomer is preferably an olefin, particularly preferably ethylene.

Examples of polymerization catalysts include radical polymerization catalysts such as azobisisobutyronitrile, benzoyl peroxide, and lauryl peroxide. The polymerization method is not particularly limited, and bulk polymerization, emulsion polymerization, solvent polymerization and the like can be employed.

Although the degree of polymerization of PVA is not particularly limited, it is preferably from 300 to 3,000. When the degree of polymerization is 300 or more, the barrier properties are less likely to decrease, and when the degree of polymerization is 3000 or less, the viscosity does not become too high, and deterioration in coatability is easily suppressed. The degree of saponification of PVA is preferably 80 mol% or more, more preferably 90 mol% or more, even more preferably 98 mol% or more. Moreover, the degree of saponification of PVA may be 100 mol % or less or 99.9 mol % or less. The degree of polymerization and degree of saponification of PVA can be measured according to the method described in JIS K 6726 (1994).

EVOH is generally a copolymer of ethylene and an acid vinyl ester such as vinyl acetate, vinyl formate, vinyl propionate, vinyl valerate, vinyl caprate, vinyl laurate, vinyl stearate, vinyl pivalate, and vinyl versatate. obtained by saponifying the

The ethylene unit content of EVOH is not particularly limited, but is preferably 10 mol% or more, more preferably 15 mol% or more, still more preferably 20 mol% or more, and particularly preferably greater than 35 mol%. The ethylene unit content of EVOH is preferably 65 mol% or less, more preferably 55 mol% or less, and even more preferably less than 50 mol%. When the ethylene unit content is 10 mol % or more, good gas barrier properties or dimensional stability under high humidity can be maintained. On the other hand, when the ethylene unit content is 65 mol% or less, gas barrier properties can be enhanced.

The ethylene unit content of EVOH can be determined by the NMR method.

Saponification can be performed with an alkali or an acid, and an alkali can be used from the viewpoint of the saponification rate. Alkali include alkali metal hydroxides such as sodium hydroxide and potassium hydroxide, and alkali metal alkoxides such as sodium ethylate, potassium ethylate and lithium methylate.

Examples of silane compounds include tetraalkoxysilanes such as tetramethoxysilane and tetraethoxysilane, and silazanes such as hexamethyldisilazane. As the silane compound, a compound generally used as a silane coupling agent or a polysiloxane compound having a siloxane bond may be used. Among silane compounds, silane coupling agents are preferred. By using the silane coupling agent, the strength in the gas barrier coating layer 4 is further improved, and the barrier properties and water resistance are easily improved.

Silane coupling agents include, for example, epoxysilane (glycidoxypropyltrimethoxysilane, glycidoxypropyltriethoxysilane, etc.), (meth)acrylsilane (acryloxypropyltrimethoxysilane, etc.), aminosilane, ureidosilane, Examples include isocyanate silane, isocyanurate silane (tris(3-trialkoxysilylpropyl) isocyanurate, etc.), mercaptosilane, and the like.

When forming the gas-barrier coating layer 4, the amount of the silane compound is adjusted from the viewpoint of maintaining the adhesion between the gas-barrier coating layer 4 and the inorganic layer 3 and the gas-barrier properties of the gas-barrier coating layer 4. Preferably 0.1 to 5.0 parts by mass, more preferably 0.3 to 5.0 parts by mass, still more preferably 0.4 to 4.5 parts by mass, relative to 1 part by mass, Particularly preferably, it is 0.5 to 4.0 parts by mass.

Although the thickness of the gas barrier coating layer 4 is not particularly limited, it is preferably 50 nm or more.

In this case, the gas barrier properties of the barrier film 10 are further improved as compared with the case where the gas barrier coating layer 4 has a thickness of less than 50 nm.

From the viewpoint of improving gas barrier properties, the thickness of the gas barrier coating layer 4 is more preferably 100 nm or more, and particularly preferably 200 nm or more.

On the other hand, the thickness of the gas barrier coating layer 4 is preferably 700 nm or less. The flexibility of the barrier film 10 is further improved as compared with the case where the thickness of the gas barrier coating layer 4 exceeds 700 nm.

From the viewpoint of further improving the flexibility of the barrier film 10, the thickness of the gas barrier coating layer 4 is more preferably 500 nm or less, particularly preferably 400 nm or less.

The barrier film 10 is formed by forming an inorganic layer 3 and a gas-barrier coating layer 4 on a base material layer 1. The base material layer 1 is made of a raw material containing biopropylene in the presence of the inorganic particles. It is obtained by a reaction, and the inorganic particles preferably contain at least one of the metal and the metal oxide. In this case, when the inorganic particles are at least one of metals and metal oxides, the metals and metal oxides are better catalysts than acid or base catalysts in the reaction to form bio-polypropylene from raw materials comprising bio-propylene. Acts as, promotes high molecular weight bio-polypropylene. Therefore, when raw materials containing biopropylene are reacted in the presence of inorganic particles, the reaction is effectively carried out and the amount of low molecular weight components of biopolypropylene is reduced. That is, the amount of low-molecular-weight components appearing on the surface of the substrate layer 1 due to bleeding out is reduced. As a result, the inorganic layer 3 is easily formed on the substrate layer 1, the dense inorganic layer 3 is formed, and the deterioration of barrier properties is further suppressed.

The content of biopropylene in the raw material is not particularly limited as long as it is greater than 0% by mass, preferably 50% by mass or more, more preferably 70% by mass or more.

The raw material may further contain petroleum-derived ethylene or ethanol in addition to biopropylene, if necessary. As ethylene, ethylene produced by known production methods such as ethylene produced by catalytic cracking or steam cracking, or ethylene obtained by Fischer-Tropsch synthesis of coal can be used. Ethanol may be used that can be produced from the hydration reaction of ethylene or from synthesis gas. Syngas is gasified hydrocarbons such as coal, natural gas, and biomass.

The reaction temperature may be, for example, 300-700°C. The method of bringing the raw material into contact with the inorganic particles is not particularly limited, but examples thereof include a method of introducing the raw material into a reactor filled with inorganic particles. Examples of reactors include fixed bed reactors, fluidized bed reactors, batch reactors, semi-batch reactors, and the like. Bed reactors are preferred, and fixed bed reactors are more preferred.

The inorganic particles may be composed of at least one of the above metals and metal oxides, and may be a metal only, a metal catalyst only, or a mixture of a metal and a metal oxide. However, the inorganic particles preferably contain metal oxides. In this case, in the barrier film 10, deterioration of barrier properties can be effectively suppressed.

The inorganic particles may be used as they are, or may be used after being blended in a binder.

The average particle size of the inorganic particles is not particularly limited because it varies depending on the conditions for synthesizing the inorganic particles, but it is preferably 0.01 to 500 μm, more preferably 0.05 to 300 μm. In this case, compared to the case where the average particle size of the inorganic particles is less than 0.01 μm, the inorganic particles are less likely to partially aggregate, and handling properties are improved. Further, when the average particle size of the inorganic particles is within the above range, the specific surface area is increased and the catalytic activity is improved as compared with the case where the average particle size of the inorganic particles exceeds 500 μm.

The amount of the inorganic particles used is not particularly limited, but is preferably 0.00000002 to 0.0002 parts by mass with respect to 100 parts by mass of the raw material. The feed rate of the raw material is also not particularly limited, but may be, for example, 0.002 to 200 tons/h, more preferably 0.02 to 20 tons/h, per 1 ton of inorganic particles. The contact time between the inorganic particles and the raw material is not particularly limited, and is, for example, 0.001 second to 1 hour, preferably 0.1 second to 1 minute.

<Method for producing barrier film>
Next, a method for manufacturing the barrier film 10 will be described.

First, the base material layer 1 is prepared. The base material layer 1 may be prepared by reacting a raw material containing biopropylene in the presence of the inorganic particles, or may be prepared by melt-kneading the biopolypropylene and the inorganic particles.

The substrate layer 1 can be obtained by single-layer extrusion molding or co-extrusion molding of the obtained resin composition containing bio-polypropylene. The molding apparatus is not particularly limited, and a multilayer T-die extruder, a multilayer inflation molding machine, or the like can be used as the molding apparatus. The number of layers constituting the base material layer 1 may be one or more, but preferably one to five layers from the viewpoint of ease of production.

Moreover, when manufacturing the base material layer 1 of non-stretching, the base material layer 1 can also be manufactured with a well-known casting apparatus.
When the stretched substrate layer 1 is produced, the substrate layer 1 may be produced by stretching a film obtained by molding using a simultaneous biaxial stretching device or a sequential biaxial stretching device. can be done.
As the stretching conditions, for example, the conditions for obtaining a known OPP film can be adopted. More specifically, in the sequential biaxial stretching method, for example, the longitudinal stretching temperature is 100° C. to 145° C., the longitudinal stretching ratio is 4.5 to 6 times, the lateral stretching temperature is 130° C. to 190° C., and the lateral stretching is Magnification may be in the range of 9 to 11 times.

Next, an anchor coat layer 2 is formed on one surface of the base material layer 1 .

Specifically, the anchor coat layer 2 is formed by applying a composition for forming the anchor coat layer 2 onto one surface of the base material layer 1 and heating and drying the composition. At this time, the heating temperature is, for example, 50 to 200° C., and the drying time is, for example, about 10 seconds to 10 minutes.

Next, an inorganic layer 3 is formed on the anchor coat layer 2 .

The inorganic layer 3 can be formed by, for example, a vacuum film forming method. Vacuum deposition methods include physical vapor deposition and chemical vapor deposition. Examples of the physical vapor deposition method include a vacuum deposition method, a sputter deposition method, an ion plating method, and the like. A vacuum vapor deposition method is particularly preferably used as the physical vapor deposition method. The vacuum deposition method includes a resistance heating vacuum deposition method, an EB (Electron Beam) heating vacuum deposition method, and an induction heating vacuum deposition method. Examples of chemical vapor deposition methods include thermal CVD, plasma CVD, and optical CVD.

Next, a gas barrier coating layer 4 is formed on the inorganic layer 3 .

The gas barrier coating layer 4 can be formed, for example, by applying a composition for forming a gas barrier coating layer onto the inorganic layer 3 and curing the composition.

As a method for applying the composition for forming a gas-barrier coating layer, a known method can be employed. Specific examples of coating methods include wet film formation methods such as gravure coating, dip coating, reverse coating, wire bar coating, and die coating.

Curing can be performed, for example, by heating.

When curing is performed by heating, the heating temperature and heating time may be set so that the solid content in the gas barrier coating layer-forming composition can be cured and the liquid such as the aqueous medium can be removed at the same time. The heating temperature may be, for example, 80 to 250° C., and the heating time may be, for example, 3 seconds to 10 minutes.

The barrier film 10 is obtained as described above.

<Packaging film>
Next, an embodiment of the packaging film of the present disclosure will be described with reference to FIG. In addition, in FIG. 2, the same components as those in FIG. 1 are denoted by the same reference numerals, and redundant explanations are omitted.

FIG. 2 is a cross-sectional view showing one embodiment of the packaging film of the present disclosure; As shown in FIG. 2 , the packaging film 20 includes a barrier film 10 and a sealant layer 21 provided on the inorganic layer 3 side of the barrier film 10 . As shown in FIG. 2 , in the barrier film 10 , the gas barrier coating layer 4 and the sealant layer 21 may be adhered with an adhesive layer 22 .

Since the packaging film 20 includes the barrier film 10 described above, it is possible to suppress deterioration of the barrier property while reducing the environmental load.

As a material for the adhesive layer 22, for example, polyester-isocyanate resin, urethane resin, polyether resin, or the like can be used.

(sealant layer)
Examples of the material for the sealant layer 21 include thermoplastic resins such as polyolefin resins and polyester resins, and polyolefin resins are generally used. Specifically, polyolefin resins include low-density polyethylene resin (LDPE), medium-density polyethylene resin (MDPE), linear low-density polyethylene resin (LLDPE), ethylene-vinyl acetate copolymer (EVA), ethylene-α Olefin copolymer, ethylene-based resin such as ethylene-(meth)acrylic acid copolymer, homopolypropylene resin (PP), propylene-ethylene random copolymer, propylene-ethylene block copolymer, propylene-α olefin copolymer Polypropylene-based resins such as coalesced, or mixtures thereof and the like can be used. The material of the sealant layer 21 can be appropriately selected from the thermoplastic resins described above depending on the intended use.

The thermoplastic resin constituting the sealant layer 21 may or may not be stretched, but from the viewpoint of lowering the melting point and facilitating heat sealing, it is preferably not stretched.

The thickness of the sealant layer 21 is appropriately determined depending on the mass of the contents, the shape of the packaging bag, etc., and is not particularly limited, but from the viewpoint of the flexibility and adhesiveness of the packaging film 20, it is 30 to 150 μm. is preferred.

<Packaging products>
An embodiment of the packaged product of the present disclosure will now be described with reference to FIG. Note that FIG. 3 is a side view showing one embodiment of the packaged product of the present disclosure. In FIG. 3, the same components as those in FIG. 1 or 2 are denoted by the same reference numerals, and overlapping descriptions are omitted.

As shown in FIG. 3 , the packaged product 40 includes a packaging container 30 and a content C enclosed within the packaging container 30 . The packaging container 30 shown in FIG. 3 is obtained by using a pair of packaging films 20 and heat-sealing the periphery of the packaging films 20 with the sealant layers 21 facing each other. 3, the adhesive layer 22 of the packaging film 20 is omitted.

This packaged product 40 is provided with the packaging container 30, and the packaging container 30 is obtained using the packaging film 20 described above. Therefore, it is possible to suppress deterioration of the barrier properties while reducing the environmental load. Therefore, according to the packaging product of the present disclosure, deterioration of the quality of the contents can be suppressed over a long period of time.

The packaging container 30 can also be obtained by folding one packaging film 20 and heat-sealing the periphery of the packaging film 20 with the sealant layers 21 facing each other.

Examples of the packaging container 30 include packaging bags, laminated tube containers, paper containers for liquids, and the like.

The content C is not particularly limited, and examples of the content C include foods, liquids, medicines, electronic parts, and the like.

The present disclosure is not limited to the above embodiments. For example, in the above-described embodiment, in the packaging film 20, the sealant layer 21 is arranged on the gas barrier coating layer 4 side of the base layer 1 of the barrier film 10. It may be arranged on the side opposite to the protective coating layer 4 .

Moreover, although the barrier film 10 includes the gas barrier coating layer 4 in the above embodiment, the barrier film 10 does not necessarily have to include the gas barrier coating layer 4 .

DESCRIPTION OF SYMBOLS 1... Base material layer, 2... Anchor-coat layer, 3... Inorganic layer, 4... Gas barrier coating layer, 10... Barrier film, 20... Packaging film, 21... Sealant layer, 30... Packaging container, 40... Packaging product.

Claims (10)

A barrier film comprising a substrate layer and an inorganic layer,
The barrier film, wherein the substrate layer is made of a resin composition containing a resin containing bio-polypropylene and inorganic particles. The barrier film is formed by forming at least the inorganic layer on the base layer,
The base material layer is obtained by reacting a raw material containing biopropylene in the presence of the inorganic particles,
2. The barrier film of claim 1, wherein the inorganic particles comprise at least one of metals and metal oxides. 2. The barrier film of claim 1, wherein said inorganic particles comprise metal oxides. 4. The barrier film of Claim 3, wherein said metal oxide is a zeolite. The barrier film according to any one of claims 1 to 4, wherein the base material layer has a biomass degree of 50% or more. further comprising an anchor coat layer between the base material layer and the inorganic layer;
The barrier film according to any one of claims 1 to 5, wherein the anchor coat layer contains an organic substance. further comprising a gas barrier coating layer covering the inorganic layer,
The barrier film according to any one of claims 1 to 6, wherein the gas barrier coating layer contains Si and C. A barrier film according to any one of claims 1 to 7;
and a sealant layer provided on the inorganic layer side of the barrier film. A packaging container obtained by using the packaging film according to claim 8. A packaged product comprising the packaging container according to claim 9 and contents enclosed in the packaging container.

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