JP2019177518A - Laminate for heat sterilization treatment, packaging material for heat sterilization treatment and package for heat sterilization treatment - Google Patents

Abstract

To provide a laminate for a heat sterilization treatment, which exhibits excellent odor adsorption property even when subjected to a heat sterilization treatment and can be used for a packaging container for sealing and packing foods and drinks, and a packaging material and a package using the laminate.SOLUTION: The laminate for a heat sterilization treatment comprises at least a base material layer, and a sealant layer in an outermost layer on one side, in which the heat sterilization treatment is performed at a treatment temperature of 100°C or higher and 140°C or lower. The base material layer has a thermoplastic resin layer, and a metal oxide vapor deposition film layer formed on the thermoplastic resin layer. The sealant layer comprises a heat-sealing resin and a hydrophobic zeolite having a SiO/AlOmolar ratio of 30/1 to 8000/1. The content percentage of the hydrophobic zeolite in the sealant layer is 0.1 mass% or more and 15 mass% or less. The heat-sealing resin has a softening point of 110°C or higher and 175°C or lower.SELECTED DRAWING: Figure 1

Description

  The present invention is excellent in adsorbing odors, particularly sulfur-based odor adsorbing, heat-sealing, and gas barrier properties, especially for retort foods and beverages, and a laminate for heat sterilization treatment, and a packaging material and packaging using the same It is about the body.

A retort food or drink packaged with a packaging material may generate a denatured odor from the packaging material and contents by heat sterilization.
The sources of modified odors in the contents are carbohydrates, fats and oils, proteins, etc. Among them, protein-modified odors, particularly sulfur-based odors, are often problematic.

As a packaging material, a packaging material containing an odor adsorbent that adsorbs an odor has been proposed (Patent Document 1). In such a packaging material, an odor adsorbent such as synthetic zeolite or activated carbon is kneaded into the resin material.
However, since such a packaging material has a problem of adsorbing not only odor but also moisture in the atmosphere and desorbing the odor once adsorbed, a sufficient odor adsorption effect can be obtained. Not.

  A packaging material containing an odor adsorbent formed by supporting an organic chemical adsorbent on an inorganic porous material is also known (Patent Document 2), but the main adsorption target adsorbs an odor component having a specific functional group. However, in a situation where a resin material is not selected, the amount of organic matter not having a functional group cannot be suppressed, and the odor component cannot be sufficiently adsorbed. Furthermore, the organic chemical adsorbent is weak at high temperature and the adsorption ability is impaired by the heat sterilization treatment, so that the sufficient adsorption effect cannot be exhibited.

Japanese Patent No. 2538487 JP 2014-233408 A

  In view of the above circumstances, an object of the present invention is to provide a laminate for heat sterilization treatment that exhibits excellent odor adsorbability even after being subjected to heat sterilization treatment, and a packaging material and packaging body using the laminate. To do.

  The present inventors have found that a laminate including a specific base material layer and a specific sealant layer achieves the above object, and has completed the present invention.

The present invention is characterized by the following points.
1. A laminate for heat sterilization treatment, comprising at least a base material layer and a sealant layer on the outermost layer on one side,
The treatment temperature of the heat sterilization treatment is 100 ° C. or more and 140 ° C. or less,
The base material layer has a thermoplastic resin layer and a metal oxide vapor deposition film layer formed on the thermoplastic resin layer,
The sealant layer includes a heat-sealable resin and a hydrophobic zeolite having a SiO ₂ / Al ₂ O ₃ molar ratio of 30/1 to 8000/1,
The content of the hydrophobic zeolite in the sealant layer is 0.1% by mass or more and 15% by mass or less,
The laminated body for heat sterilization treatment whose softening point of the said heat sealable resin is 110 degreeC or more and 175 degrees C or less.
2. The laminate for heat sterilization treatment according to 1 above, wherein the metal oxide vapor deposition film layer includes an aluminum oxide vapor deposition film or a silicon oxide vapor deposition film.
3. The laminate for heat sterilization treatment according to 1 or 2 above, wherein the base material layer further includes a barrier coat resin layer formed on the metal vapor deposition film layer.
4). The laminate for heat sterilization treatment according to any one of the above 1 to 3, wherein the barrier coat resin layer is made of a water-soluble polymer.
5. The laminate for heat sterilization treatment according to any one of the above 1 to 4, wherein the heat sealable resin is a polypropylene resin.
6). A packaging material for heat sterilization treatment produced using the laminate for heat sterilization treatment according to any one of 1 to 5 above.
7). A package for heat sterilization treatment, produced using the packaging material for heat sterilization treatment described in 6 above.

According to the present invention, even if the package and contents are subjected to heat sterilization, the laminate for heat sterilization that exhibits excellent odor adsorbability, and further exhibits excellent gas barrier properties, and A packaging material and a package using the same can be obtained.
In addition, it can be sterilized at a high temperature to prevent the entry of oxygen and water vapor gas from the outside, and it can prevent the leakage of odors from the inside and the evaporation of moisture, enabling long-term storage of the contents. And

It is sectional drawing which shows one example of the laminated body for heat sterilization processes of this invention. It is sectional drawing which shows one example of another aspect of the laminated body for heat sterilization treatment of this invention. It is sectional drawing which shows one example of another aspect of the laminated body for heat sterilization processes of this invention.

The present invention will be described below with reference to the drawings. However, the present invention is not limited to these specifically exemplified forms and various specifically described structures.
In each drawing, the size and ratio of members may be changed or exaggerated for easy understanding. For ease of viewing, unnecessary parts and repeated reference numerals may be omitted for explanation.
In the present invention, a film and a sheet are collectively referred to as a film.

The present invention includes at least a base material layer, a laminate for heat sterilization treatment including a sealant layer on the outermost layer on one side, and a packaging material for heat sterilization treatment and heating produced from the laminate for heat sterilization treatment It is a package for sterilization treatment. The package for heat sterilization treatment can be used for a packaging container that hermetically fills food and drink as contents.
The treatment temperature for the heat sterilization treatment is preferably 100 ° C. or higher and 140 ° C. or lower.

The laminate for heat sterilization treatment of the present invention has a heat seal property by including a sealant layer on the outermost layer on one side, and has a SiO ₂ / Al ₂ O ₃ molar ratio of 30/1 to 8000/1. It contains a high odor adsorption effect for a wide variety of sulfur-based odor components. The odor adsorption effect is not lost by the heat sterilization treatment.

<Heat treatment>
In the present invention, examples of the heat treatment include a laminate, a packaging material, a heat treatment for producing the package, a heat treatment for the package contents, and a heat sterilization treatment for the package and contents. The heating temperature varies depending on each heat treatment, the material structure of the laminate, and the content composition.
When the heat treatment is performed at a high temperature, the resin component may be altered and the odor adsorbent may be deteriorated, and the influence of the temperature of each heat treatment must be considered.

In the present invention, the heat processing for the package contents is not particularly regarded as a problem in the present invention because the processing requiring high temperature is usually completed in the stage before filling the package.
In the film forming process, it is necessary to heat to a temperature at which the resin is sufficiently melted. The heating temperature varies depending on the resin. For example, in the case of a polyethylene resin, it is heated to 110 ° C. to 200 ° C. Is heated to 130 to 260 ° C.
Therefore, the film-forming process is easy to generate a denatured odor due to the alteration of the resin component, particularly in the heat processing for producing the laminate, the packaging material, and the package, and can be generated from the entire package. The content can be transferred.

  For example, when the resin component of the sealant layer is a polyethylene-based resin, the heat-sealing process when producing the package is heated to 90 ° C. to 200 ° C., and in the case of a polypropylene-based resin, 110 ° C. to 260 ° C. However, since the heating area is small, the heating time is short, and the contents are not in contact with each other, there is little generation of modified odor due to alteration of the resin component, and the contents There is little shift to.

  Regardless of the type of resin component of the package, the heat sterilization treatment for the package and the contents is usually performed within the range of 100 ° C. or more and 140 ° C. or less, particularly at 121 ° C. If the resin component has insufficient heat resistance, it can generate a modified odor from the resin component, and the modified odor from the resin component can be Since it can be generated from the whole body, it can shift to the contents.

<Layer structure of laminate for heat sterilization treatment>
As shown in FIG. 1, the laminate for heat sterilization treatment of the present invention includes at least a base material layer and a sealant layer, and the base material layer is formed on the thermoplastic resin layer and the thermoplastic resin layer. And a metal oxide deposited film layer.
The base material layer and the sealant layer may be bonded via an adhesive layer as necessary.

Furthermore, as shown in FIG. 2, as another aspect of the heat sterilization laminate of the present invention, the base material layer further has a barrier coat resin layer formed on the metal vapor deposition film layer.
The barrier coat resin layer and the sealant layer may be bonded via an adhesive layer as necessary.
In the laminate for heat sterilization treatment of the present invention, the sealant layer is the outermost layer on one side, and other layers can be included as needed in addition to the base material layer and the sealant layer.

<Base material layer>
The base material layer included in the laminate for heat sterilization treatment of the present invention has a thermoplastic resin layer and a metal oxide vapor deposition film layer formed on the thermoplastic resin layer.
Furthermore, the base material layer can include other layers as required in addition to the thermoplastic resin layer and the metal oxide vapor deposition film layer. For example, as shown in FIG. 2, the base material layer may further include a barrier coat resin layer formed on the metal vapor deposition film layer as another embodiment.
The thickness of the base material layer is preferably 5 to 30 μm, more preferably 10 to 30 μm.
Each of the thermoplastic resin layer and the metal oxide vapor deposition film layer may be a single layer or a multilayer of two or more layers.

In the present invention, the surface of the thermoplastic resin layer may be provided with a desired surface treatment layer in advance, if necessary, in order to improve the adhesion with the metal oxide vapor deposition film.
For example, corona discharge treatment, ozone treatment, pretreatment such as low temperature plasma treatment using oxygen gas or nitrogen gas, glow discharge treatment, oxidation treatment using chemicals, etc. is optionally performed, corona treatment layer, ozone treatment A layer, a plasma treatment layer, an oxidation treatment layer, or the like can be formed and provided.

  Alternatively, various coating agent layers such as a primer coating agent layer, an undercoat agent layer, an anchor coating agent layer, an adhesive layer, and a vapor deposition anchor coating agent layer are arbitrarily formed on the surface of the thermoplastic resin layer, and the surface treatment layer It can also be.

  Examples of the various coating agent layers include polyester resins, polyamide resins, polyurethane resins, epoxy resins, phenol resins, (meth) acrylic resins, polyvinyl acetate resins, and polyolefins such as polyethylene and polypropylene. It is possible to use a resin composition whose main component is a vehicle resin or a copolymer or modified resin thereof, a cellulose resin, or the like.

  A film for a thermoplastic resin layer that satisfies the above requirements is also commercially available. Examples of the film suitably used in the present invention include a biaxially stretched PET film E5100 (thickness) manufactured by Toyobo Co., Ltd. 12 μm, single-sided corona treatment), biaxially stretched PET film E5200 (thickness 12 μm, double-sided corona treatment), and biaxially stretched nylon film ONBC (thickness 15 μm, double-sided corona treatment) manufactured by Unitika Ltd.

  Furthermore, a film satisfying the above requirements, in which a metal oxide vapor-deposited film is formed on a thermoplastic resin layer, is also commercially available. Examples of the film suitably used in the present invention include a PVD method. Examples include alumina vapor-deposited IB-PET-PIR (thickness 12 μm) and silica-deposited IB-ON-UB (thickness 15 μm) manufactured by Dai Nippon Printing Co., Ltd., which are PET films obtained by vapor-depositing alumina on one side.

(Thermoplastic resin)
The thermoplastic resin used for the base material layer is molded and used as a film, has excellent chemical or physical strength, and can withstand the conditions for forming a metal oxide vapor-deposited film. It is a thermoplastic resin that can be satisfactorily maintained without impairing the properties of the deposited film.

  Examples of such resins include polyolefin resins such as polyethylene resins and polypropylene resins, cyclic polyolefin resins, polystyrene resins, acrylonitrile-styrene copolymers (AS resins), and acrylonitrile-butadiene-styrene copolymers. (ABS resin), poly (meth) acrylic resin, polycarbonate resin, polyester resins such as polyethylene terephthalate and polyethylene naphthalate, polyamide resins such as various nylons, polyurethane resins, acetal resins, cellulose resins, etc. The various resin of this is mentioned.

  In the present invention, among the above resins, it is particularly preferable to use a film or sheet of a polyester resin, a polyolefin resin, or a polyamide resin.

In the present invention, the thermoplastic resin used for the base material layer can be formed into a film by various publicly known film forming methods.
For example, a method of forming a film using a film forming method such as an extrusion method, a cast molding method, a T-die method, a cutting method, an inflation method, etc., using two or more types of resins. Examples thereof include a method of forming a multilayer coextrusion film, a method of mixing two or more kinds of resins before forming a film, and forming a film by the above film forming method. Furthermore, it can be set as the film extended | stretched to the uniaxial or biaxial direction using a tenter system, a tubular llama system, etc.

In addition, when forming a thermoplastic resin into a film, for example, film processability, heat resistance, weather resistance, mechanical properties, dimensional stability, antioxidant properties, slipperiness, mold release properties, flame retardancy, Various plastic compounding agents and additives can be added for the purpose of improving and modifying antifungal properties, electrical characteristics, strength, etc. Depending on the purpose, it can be added arbitrarily.
In the above, as a general additive, for example, a lubricant, a crosslinking agent, an antioxidant, an ultraviolet absorber, a light stabilizer, a filler, a reinforcing agent, an antistatic agent, a pigment, a modifying resin, and the like are used. be able to.

(Metal oxide deposition film)
In the present invention, the vapor deposited metal oxide film can impart gas barrier properties to the laminate.
The metal oxide vapor deposition film may be a single layer or two or more layers. When there are two or more layers, each may have the same composition or a different composition.

Examples of the metal oxide forming the metal oxide vapor deposition film include aluminum (Al), silicon (Si), magnesium (Mg), calcium (Ca), potassium (K), tin (Sn), and sodium (Na). , Boron (B), titanium (Ti), lead (Pb), zirconium (Zr), yttrium (Y), and other metal oxides.
Among the above metal oxides, an oxide of aluminum (Al) or silicon (Si) is preferable, and an oxide of aluminum (Al) is more preferable.

The metal oxide is, for example, MO _x (wherein like such AlO _x, SiO _x, MgO _x, M represents a metal element, the value of x, the average of the number of oxygen atoms to one M atom Represents the value, and the range of the value varies depending on the metal element).
In the above, x = 0 is a case of non-oxidized metal, and the upper limit of the range of x is a value when it is completely oxidized.
As the range of the value of x, aluminum (Al) is 0 <x ≦ 1.5, silicon (Si) is 0 <x ≦ 2, magnesium (Mg) is 0 <x ≦ 1, and calcium (Ca) is 0. <X ≦ 1, potassium (K) 0 <x ≦ 0.5, tin (Sn) 0 <x ≦ 2, sodium (Na) 0 <x ≦ 0.5, boron (B) 0 <x ≦ 1,5, titanium (Ti) 0 <x ≦ 2, lead (Pb) 0 <x ≦ 1, zirconium (Zr) 0 <x ≦ 2, yttrium (Y) 0 <x ≦ 1.5 , Values in the range can be taken.

  In the present invention, it is particularly preferable to use aluminum oxide of 0.5 ≦ x ≦ 1.5 or silicon oxide of 1.0 ≦ x ≦ 2.0, and aluminum oxide of 0.5 ≦ x ≦ 1.5. Most preferably, is used.

In this invention, the film thickness of a metal oxide vapor deposition film can be arbitrarily selected and formed, for example in the range of 5-400 nm, Preferably, 10-100 nm.
The appropriate film thickness varies depending on the type of metal oxide used, and in the case of aluminum oxide or silicon oxide, 5 to 50 nm is preferable, and 10 to 30 nm is more preferable.
If it is thicker than the above range, the rigidity of the laminate tends to be too strong, and the production cost tends to increase because it takes a long time to form the metal oxide vapor-deposited film. It is difficult to obtain a sufficient gas barrier property.

  In the present invention, as a method for forming a metal oxide deposition film, for example, a physical vapor deposition method (Physical Vapor Deposition method, PVD method) such as a vacuum deposition method, a sputtering method, and an ion plating method, or plasma chemistry is used. Examples thereof include a chemical vapor deposition method (Chemical Vapor Deposition method, CVD method) such as a vapor deposition method, a thermal chemical vapor deposition method, and a photochemical vapor deposition method.

(Barrier coat resin layer)
The barrier coat resin layer is a layer formed on the metal oxide vapor deposition film layer in contact with the metal oxide vapor deposition film layer, and is a layer containing a resin. Moreover, the barrier coat resin layer and the sealant layer may be bonded via an adhesive layer as necessary.
The laminate for heat sterilization treatment can exhibit excellent gas barrier properties due to a synergistic effect by including a combination of a metal oxide vapor deposition film layer and a barrier coat resin layer.

  The barrier coat resin layer in the present invention is a gas barrier property obtained by hydrolyzing and polycondensing a metal alkoxide and a water-soluble polymer by the sol-gel method in the presence of a sol-gel method catalyst, acid, water and an organic solvent. It is a film formed by applying and drying the composition. In some cases, the gas barrier composition may further contain a silane coupling agent.

The metal alkoxide has a general formula R ¹ _n M (OR ² ) _m (wherein R ¹ and R ² represent an organic group having 1 to 8 carbon atoms, M represents a metal atom, n Represents an integer of 0 or more, m represents an integer of 1 or more, and n + m represents a valence of M. One or more metal alkoxides represented by Here, as the metal atom M, silicon, zirconium, titanium, aluminum or the like can be used. Specific examples of the organic group represented by R ¹ and R ² include alkyl groups such as a methyl group, an ethyl group, an n-propyl group, an i-propyl group, an n-butyl group, and an i-butyl group. Can be mentioned. In the same molecule, these alkyl groups may be the same or different. Examples of such metal alkoxides include tetramethoxysilane Si (OCH ₃ ) ₄ , tetraethoxysilane Si (OC ₂ H ₅ ) ₄ , tetrapropoxysilane Si (OC ₃ H ₇ ) ₄ , tetrabutoxysilane Si (OC ₄ H ₉ ) ₄ etc.

In addition, as the water-soluble polymer, any one or both of a polyvinyl alcohol resin and an ethylene / vinyl alcohol copolymer can be preferably used.
As the sol-gel catalyst, a tertiary amine that is substantially unnecessary in water and soluble in an organic solvent is preferably used, and N, N-dimethylbenzylamine is particularly preferable.
Examples of the acid include mineral acids such as sulfuric acid, hydrochloric acid, and nitric acid, and organic acids such as acetic acid and tartaric acid.
Furthermore, as said organic solvent, methyl alcohol, ethyl alcohol, isopropyl alcohol, n-propyl alcohol etc. can be used, for example.

  The content of the water-soluble polymer in the gas barrier composition is preferably in the range of 5 to 500 parts by mass with respect to 100 parts by mass of the total amount of the metal alkoxide. When the amount is less than the above range, a sufficient gas barrier effect is hardly exhibited. When the amount is more than the above range, brittleness of the formed barrier coat resin layer is increased, and the weather resistance and the like are not preferable.

When the above gas barrier composition is applied on the metal oxide vapor deposition film layer and heated to remove the solvent and the alcohol produced by the polycondensation reaction, the polycondensation reaction is completed, and a transparent barrier coat resin layer is formed. It is formed. Here, the hydroxyl group generated by hydrolysis and the silanol group derived from the silane coupling agent are bonded to the hydroxyl group on the surface of the metal oxide vapor-deposited film layer, so that the adhesion between the vapor-deposited film and the barrier coat resin layer is It will be good.

The barrier coat resin layer may be a single layer or a multilayer of two or more layers. When there are two or more layers, each may have the same composition or a different composition.
The thickness of the barrier coat resin layer is preferably 0.01 μm or more and 30 μm or less, and more preferably 0.1 μm or more and 10 μm or less.
If it is thinner than the above range, the gas barrier effect tends to be insufficient, and even if it is thicker than the above range, the gas barrier effect is not particularly improved, and the rigidity of the laminate tends to be too strong.

  The method for forming the barrier coat resin layer is a method of coating and drying on the metal oxide vapor deposited film layer, an extrusion coating method on the metal oxide vapor deposited film layer, and a metal film by hot-pressing the formed barrier coat resin layer. The method of sticking on the oxide vapor deposition film layer etc. can be selected suitably.

<Adhesive layer>
In this invention, an adhesive bond layer is a layer contained as needed.
It is preferable to use an adhesive for dry lamination, and examples thereof include a urethane adhesive, a vinyl adhesive, an acrylic adhesive, an epoxy adhesive, and an ester adhesive.

<Sealant layer>
The sealant layer of the laminate for heat sterilization treatment of the present invention contains a heat sealable resin and a hydrophobic zeolite.
The sealant layer may be a single layer or a multilayer of two or more layers. In the case of two or more layers, each may have the same composition or a different composition, and may include a layer made of only a heat-sealable resin. Furthermore, if necessary, a layer not containing a heat-sealable resin or a hydrophobic zeolite can be included.

  Furthermore, in the case of a single layer structure, as shown in FIG. 1, the single layer contains a heat-sealable resin, a hydrophobic zeolite, and an inorganic odor decomposing agent. 2 and 3, the heat-sealable resin, the hydrophobic zeolite, and the inorganic odor decomposing agent may be simultaneously contained in the same one layer or two or more layers. Each may contain one or more of the group consisting of a heat-sealable resin, a hydrophobic zeolite, and an inorganic odor decomposing agent, and even if the multiple layers have the same composition, different compositions It may be a layer.

In the case of a multilayer structure of two or more layers, a functional layer having various functions can be included as necessary. The functional layer may not contain any of heat-sealable resin, hydrophobic zeolite, and inorganic odor decomposing agent.
Furthermore, in the case of a multilayer structure of two or more layers, an adhesive layer may be present between the respective layers.

  In the present invention, a layer containing a hydrophobic zeolite and a heat-sealable resin in the sealant layer is also referred to as an odor adsorbing layer, and a layer not containing the hydrophobic zeolite is also referred to as a non-odor adsorbing layer.

  In addition, for sealant layers, antioxidants, UV absorbers, light stabilizers, antistatic agents, antiblocking agents, flame retardants, crosslinking agents, colorants, pigments, lubricants, fillers, reinforcing agents, modifiers One or more of various plastic compounding agents and additives such as resins for use can be added as appropriate. The addition amount can be arbitrarily added from a very small amount to several tens of percent depending on the purpose.

The thickness of the sealant layer is preferably 10 μm or more and 250 μm or less, 30 μm or more, 1
More preferably, it is 50 μm or less.
If it is thinner than the above range, the odor component adsorption performance tends to be insufficient, and the heat seal strength and laminate strength tend to be insufficient. When it is thicker than the above range, the rigidity of the laminate becomes too strong, and the workability and the feeling of use of the package are likely to deteriorate.

  The thickness of the odor adsorbing layer is preferably 7 μm or more and 250 μm or less, and more preferably 10 μm or more and 150 μm or less.

On the surface of each layer constituting the sealant layer or the sealant layer, a desired surface treatment layer can be provided in advance in order to improve adhesion as necessary.
For example, corona discharge treatment, ozone treatment, pretreatment such as low temperature plasma treatment using oxygen gas or nitrogen gas, glow discharge treatment, oxidation treatment using chemicals, etc. is optionally performed, corona treatment layer, ozone treatment A layer, a plasma treatment layer, an oxidation treatment layer, or the like can be formed and provided.
Alternatively, a primer coating agent layer, an undercoat agent layer, an anchor coating agent layer, an adhesive layer, a vapor deposition anchor coating agent layer, and the like can be arbitrarily formed to form a surface treatment layer.

Examples of the various coating agent layers include polyester resins, polyamide resins, polyurethane resins, epoxy resins, phenol resins, (meth) acrylic resins, polyvinyl acetate resins, and polyolefins such as polyethylene and polypropylene. It is possible to use a resin composition whose main component is a vehicle resin or a copolymer or modified resin thereof, a cellulose resin, or the like.
As a method for laminating the sealant layer, a dry laminating method, an extrusion coating method, a sand laminating method, or the like can be appropriately selected.

(Heat sealable resin)
In the present invention, the heat-sealable resin is a resin that can be melted by heat and fused to each other. The temperature of the heat sealing process varies depending on the heat sealing resin used.
Furthermore, the heat-sealable resin is a resin that can sufficiently disperse the hydrophobic zeolite.
In order to apply a heat sterilization treatment of 100 ° C. or higher and 140 ° C. or lower, the softening point of the heat-sealable resin is preferably 110 ° C. or higher and 175 ° C. or lower.

  Examples of the heat-sealable resin preferably used in the present invention include propylene homopolymer, copolymer of propylene and unsaturated carboxylic acid, copolymer of propylene and unsaturated carboxylic acid ester, propylene / α -Polypropylene resins such as olefin copolymers, random copolymers or block copolymers of ethylene-propylene copolymers.

  As said unsaturated carboxylic acid, acrylic acid, methacrylic acid, maleic anhydride, fumaric acid, etc. are mentioned, It can copolymerize using these 1 type (s) or 2 or more types.

  Examples of the unsaturated carboxylic acid ester include acrylic acid ester, methacrylic acid ester, maleic anhydride ester, and fumaric acid ester, and these can be copolymerized using one or more of them.

Among the heat-sealable resins, polypropylene resins are preferably used from the viewpoint of heat resistance.
Heat seal processing means that when manufacturing a packaging container, wrap the packaging material in two or prepare two packaging materials, face each other with their sealant layers facing each other, and melt their peripheral edges And fusing each other. The heating temperature varies depending on the resin.
As a heat sealing method, for example, a known method such as a bar seal, a rotary roll seal, a belt seal, an impulse seal, a high frequency seal, or an ultrasonic seal can be used.
When a polypropylene resin is used as the heat sealable resin, the heat seal temperature is preferably 110 ° C. or higher and 260 ° C. or lower.

(Hydrophobic zeolite)
Hydrophobic zeolites of the present invention is contained in the sealant layer, and exhibits high odor adsorption capacity, in order to suppress the adsorption of water, the molar ratio of SiO ₂ / Al ₂ O ₃ is 30 / 1-8000 / One is preferred. In general, the higher the SiO ₂ / Al ₂ O ₃ molar ratio of zeolite, the higher the hydrophobicity.
The hydrophobic zeolite in the present invention does not lose its odor adsorbing ability even when the packaging material is exposed to 230 ° C. or more, and can exhibit the effect of adsorbing odor components.
Hydrophobic zeolite may have any outer shape such as a spherical shape, a rod shape, an elliptical shape, and may have any shape such as a powder shape, a lump shape, and a granular shape. From the viewpoint of uniform dispersion in the resin, kneading characteristics and the like, a powder form is preferable.

In the present invention, the average particle size of the hydrophobic zeolite can be appropriately selected from those having an average particle size depending on the application, but those having an average particle size of 0.01 μm to 10 μm are preferable. Here, the average particle diameter is a value measured by a dynamic light scattering method.
When the average particle diameter is smaller than 0.01 μm, aggregation of the hydrophobic zeolite tends to occur and the dispersibility in the sealant layer tends to be lowered. In addition, when the average particle size is larger than 10 μm, the film forming property of the sealant layer tends to be inferior, so that it is difficult to add a large amount of hydrophobic zeolite, and the surface area is further reduced. There is a possibility that the effect cannot be obtained.

The content of the hydrophobic zeolite in all the sealant layers is preferably 0.1% by mass or more and 15% by mass or less.
If it is 0.1% by mass or more, it is possible to exert a sufficient odor adsorption effect, but in order to obtain a good odor adsorption effect as a package, it is more preferably 0.3% by mass or more. More preferably, the content is 0.5% by mass or more.
On the other hand, the content is preferably 15% by mass or less and more preferably 10% by mass or less in order to obtain good film forming properties and heat sealability.

<Method for producing laminate for heat sterilization>
As a method for producing and laminating each layer constituting the laminate for heat sterilization treatment, for example, using one kind of resin composition, production methods such as an extrusion method, a cast molding method, a T-die method, a cutting method, and an inflation method are used. A method for forming a film using a film forming method, a method for forming a multi-layer coextrusion film using two or more types of resin compositions, and a method for forming the film by mixing before forming two or more types of resin compositions. The film forming method, the dry lamination method, the sand laminating method, and the like can be selected as appropriate, and film formation, lamination, or film formation and lamination can be performed simultaneously.
The same method can be applied to the case where the laminate for heat sterilization treatment of the present invention is laminated on another film layer to produce a laminate.

<Packaging materials for heat sterilization>
By using the laminate for heat sterilization treatment of the present invention, for example, surface treatment can be performed or cut as necessary to obtain a packaging material for heat sterilization treatment.

<Packaging for heat sterilization treatment>
By using the packaging material for heat sterilization treatment of the present invention, for example, a bag for heat sterilization treatment such as a packaging bag can be produced by making a bag so that the sealant layer becomes the innermost layer.
In order to manufacture a packaging bag, the above-mentioned packaging material for heat sterilization treatment is folded in half, or two packaging materials for heat sterilization treatment are prepared, the sealant layers are opposed to each other, and the peripheral edges thereof For example, standing pouch type, side seal type, two-side seal type, three-side seal type, four-side seal type, envelope-attached seal type, joint-attached seal type (pillow seal type), pleated seal type, flat bottom seal type, Various types of packaging bags can be obtained by heat-sealing by a heat-seal form such as a square-bottom seal type or a gusset type.

  In the present invention, the contents to be sealed and packed in the packaging bag include retort foods and drinks and fresh foods, for example, drinks such as liquor, fruit juice drinks, beverages such as mineral water, liquid seasonings such as soy sauce and sauces. Fresh foods such as liquid food and drink such as food, curry, stew and soup.

<Raw materials>
The main raw materials used in the examples of the present invention are as follows.
[Film for substrate layer]
IB-PET-PIR: Dai Nippon Printing Co., Ltd. PVD method aluminum oxide vapor deposition PET film with a barrier coat resin layer. It has a barrier coat resin layer containing a polyvinyl alcohol-based resin. The thickness structure is PET film (12 μm) / aluminum oxide vapor deposition layer (20 nm) / barrier coat resin layer (250 nm).
[Film for functional layer]
Nylon film 1: manufactured by Unitika, biaxially stretched nylon film, product number: emblem ONBC, film thickness: 15 μm.
[adhesive]
-Adhesive 1: DL (dry laminate) adhesive. Rock bond JRU-77T / Adlock H-7 manufactured by Rock Paint Co., Ltd .; blending ratio 10/1.
[Hydrophobic zeolite]
Hydrophobic zeolite 1: Shiruton MT100 manufactured by Mizusawa Chemical Co., Ltd. SiO ₂ / Al ₂ O ₃ molar ratio = 100/1, average particle size = 3 to 4.5 μm.
Hydrophobic zeolite 2: Shilton MT400 manufactured by Mizusawa Chemical Co., Ltd. SiO ₂ / Al ₂ O ₃ molar ratio = 400/1, average particle diameter = 5 to 7 μm.
Hydrophobic zeolite 3: Shiruton MT2000 manufactured by Mizusawa Chemical Co., Ltd. SiO ₂ / Al ₂ O ₃ molar ratio = 2000/1, average particle diameter = 2-4 μm.
Hydrophobic zeolite 4: Mizusuka Sieves EX-122 manufactured by Mizusawa Chemical Co., Ltd. SiO ₂ / Al ₂ O ₃ molar ratio = 32/1, average particle size = 2.5 to 5.5 μm.
Hydrophobic zeolite 5: Shiruton MT-8000 manufactured by Mizusawa Chemical Co., Ltd. SiO ₂ / Al ₂ O ₃ molar ratio = 8000/1, average particle diameter = 0.8 μm.
Hydrophilic zeolite 1: Mizusuka Sieves Y-420 manufactured by Mizusawa Chemical Co., Ltd. SiO ₂ / Al ₂ O ₃ molar ratio = 5/1, average particle diameter = 5 μm.
[Heat sealable resin]
Heat-sealable resin 1: Wintech WFX4M manufactured by Nippon Polypro Co., Ltd. Propylene / α containing 90% by mass or more of propylene in the raw material? Olefin copolymer. MFR 7 g / 10 min, Vicat softening point 110 ° C.
Heat-sealable resin 2: PC480A manufactured by Sun Allomer. Block-polypropylene, MFR 2 g / 10 min, melting point 165 ° C.
Heat-sealable resin 3: LDPE, LC522 manufactured by Nippon Polyethylene Co., Ltd. MFR 4 g / 10 min, Vicat softening point 96 ° C.

<Preparation of master batch for sealant layer>
[Preparation of Masterbatch 1]
The following raw materials were melt blended to obtain a master batch 1 for an odor adsorbing layer.
Hydrophobic zeolite 1 10 parts by mass Heat-sealable resin 1 90 parts by mass [Preparation of masterbatches 2-9]
According to the composition in Table 1, the same operation as in Masterbatch 1 was performed to obtain Masterbatches 2-9.

<Production and evaluation of laminate>
[Example 1]
The master batch 1 and the heat-sealable resin 1 were melt blended at the following ratio to prepare a resin composition for an odor adsorbing layer.
Masterbatch 1 50 parts by mass Heat-sealable resin 1 50 parts by mass

Using the obtained resin composition for odor adsorbing layer and heat-sealable resin 1, an inflation film was formed at 200 ° C., and non-odor adsorbing layer 1 (12 μm) / odor adsorbing layer (36 μm) / non-odor adsorbing layer An odor adsorbing film for a sealant layer having a structure of 2 (12 μm) was obtained. The hydrophobic zeolite content in the odor adsorbing film is 3% by mass.
After applying and drying the adhesive 1 on the barrier coat resin layer side of the IB-PET-PIR, the nylon film 1 is attached, and further, the adhesive 1 is applied to the nylon film 1 and dried. The odor adsorbing film for the sealant layer was pasted to obtain a film-like laminate, and various evaluations were performed. Table 2 shows the detailed configuration and evaluation results of the laminate.

(Schematic layer structure of the laminate)
IB-PET-PIR film (12 μm) / adhesive 1 layer (4 μm) / nylon film 1 (15 μm) / adhesive 1 layer (4 μm) / odor adsorbing film (60 μm) (total thickness 95 μm)

[Examples 2 to 5, Comparative Examples 3 and 4]
According to the structure of the laminated body of Table 2, the resin composition for odor adsorption layers was produced, and it operated similarly to Example 1, and obtained the odor adsorption film for sealant layers. The hydrophobic zeolite content in the odor adsorbing film is as shown in Table 2.
And like Example 1, using the obtained odor adsorption film, the film-form laminated body was obtained and various evaluation was performed. Table 2 shows the detailed configuration and evaluation results of the laminate.

[Example 6]
According to the structure of the laminated body of Table 2, the resin composition for odor adsorption layers was produced using the masterbatch 6 and the heat sealable resin 2, and the resin composition for odor adsorption layers and the heat sealable resin 2 were used. The film was cast at 230 ° C. to obtain an odor adsorbing film for a sealant layer having a structure of non-odor adsorbing layer 1 (12 μm) / odor adsorbing layer (36 μm) / non-odor adsorbing layer 2 (12 μm). The content of the hydrophobic zeolite in the odor adsorbing film is 3% by mass.
And like Example 1, using the obtained odor adsorption film, the film-form laminated body was obtained and various evaluation was performed. Table 2 shows the detailed configuration and evaluation results of the laminate.

[Examples 7 and 8, Comparative Example 2]
According to the structure of the laminated body described in Table 2, an odor adsorbing layer resin composition was prepared and formed into an inflation film at 200 ° C. to obtain an odor adsorbing film for a sealant layer consisting of only an odor adsorbing layer (60 μm). It was. The hydrophobic zeolite content in the odor adsorbing film is as shown in Table 2.
And like Example 1, using the obtained odor adsorption film, the film-form laminated body was obtained and various evaluation was performed. Table 2 shows the detailed configuration and evaluation results of the laminate.

[Comparative Example 1]
Film formation was performed at 200 ° C. using only the heat-sealable resin 1 to obtain an odor adsorbing film for a sealant layer consisting of only one heat-sealable resin layer (60 μm). The hydrophobic zeolite content in the odor adsorbing film is 0% by mass.
And like Example 1, using the obtained odor adsorption film, the film-form laminated body was obtained and various evaluation was performed. Table 2 shows the detailed configuration and evaluation results of the laminate.

[Result Summary]
Examples 1 to 8 which are laminates for heat sterilization treatment of the present invention all showed good heat resistance, heat sealability, and odor concentration reduction rate of hydrogen sulfide and dimethyl sulfide.
Comparative Examples 1 and 4 which do not contain the hydrophobic zeolite according to the present invention having a SiO ₂ / Al ₂ O ₃ molar ratio of 30/1 to 8000/1 in the sealant layer are insufficient hydrogen sulfide and / or dimethyl sulfide. Comparative Example 3 using a heat-sealable resin having a softening point of less than 110 ° C. for the sealant layer was able to produce a laminate, but was inferior in heat resistance. Canceled. Further, in Comparative Example 2 in which the content of the hydrophobic zeolite according to the present invention in the sealant layer was too much, the bag was broken in the heat resistance evaluation due to a significant decrease in the seal strength, which was unacceptable.

<Evaluation method>
[Heat-resistant]
Using the laminates obtained in the examples and comparative examples, a four-side sealed pouch (outside dimension: 13 cm × 17 cm) filled with 100 cc of water was prepared and subjected to heat sterilization treatment under the following conditions to deform the laminate components. And the presence or absence of alteration was confirmed. The presence or absence of alteration was visually observed.
Atmospheric pressure: 0.21 MPa
Temperature: 121 ° C
Treatment time: 30 minutes Criteria: A case where no wrinkles occurred on the pouch surface and no bag breakage was determined to be acceptable.

[Heat sealability]
In the heat resistance evaluation, if the seal part was not peeled off after the heat sterilization treatment, it was accepted, and if it was peeled off and the bag was broken, it was judged unacceptable.

[Density reduction rate]
Using the laminates obtained in Examples and Comparative Examples, a pouch bag (11 cm × 15 cm) heat-sealed on four sides was prepared, and the following evaluation gas was injected into the pouch bag with a syringe, After leaving at 25 ° C. for 2 days, the air in the pouch bag is collected with a syringe, the concentration of hydrogen sulfide and dimethyl sulfide is measured with GC and a detector tube, and each of hydrogen sulfide and dimethyl sulfide in the pouch bag is measured. The reduction rate of concentration was calculated.
(Evaluation gas)
Hydrogen sulfide: 25ppm
Dimethyl sulfide: 30ppm
Other ingredients: Air

1. 1. Laminate for heat sterilization treatment Base material layer 3. 3. Thermoplastic resin layer 4. Metal oxide deposition film layer Sealant layer 5a. Odor adsorbing layer (with heat-sealable resin + hydrophobic zeolite)
5b. Non-odor adsorbing layer (containing heat-sealable resin)
6). 6. Barrier coat resin layer Adhesive layer

Claims (7)

A laminate for heat sterilization treatment, comprising at least a base material layer and a sealant layer on the outermost layer on one side,
The treatment temperature of the heat sterilization treatment is 100 ° C. or more and 140 ° C. or less,
The base material layer has a thermoplastic resin layer and a metal oxide vapor deposition film layer formed on the thermoplastic resin layer,
The sealant layer includes a heat-sealable resin and a hydrophobic zeolite having a SiO ₂ / Al ₂ O ₃ molar ratio of 30/1 to 8000/1,
The content of the hydrophobic zeolite in the sealant layer is 0.1% by mass or more and 15% by mass or less,
The laminated body for heat sterilization treatment whose softening point of the said heat sealable resin is 110 degreeC or more and 175 degrees C or less.   The laminated body for heat sterilization treatment of Claim 1 in which the said metal oxide vapor deposition film layer contains an aluminum oxide vapor deposition film or a silicon oxide vapor deposition film.   The said base material layer is a laminated body for heat sterilization processes of Claim 1 or 2 containing the barrier coat resin layer formed on the said metal vapor deposition film layer further.   The laminate for heat sterilization treatment according to any one of claims 1 to 3, wherein the barrier coat resin layer is made of a water-soluble polymer.   The laminate for heat sterilization treatment according to any one of claims 1 to 4, wherein the heat sealable resin is a polypropylene resin.   The packaging material for heat sterilization processing produced using the laminated body for heat sterilization processing of any one of Claims 1-5.   A package for heat sterilization treatment, produced using the packaging material for heat sterilization treatment according to claim 6.

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