JP5640603B2 - Packaging material for pressure and heat sterilization - Google Patents

Description

  The present invention relates to a packaging material for heat sterilization having high oxygen and water vapor barrier properties.

Food packaging materials, such as pouch materials for retort foods, are laminated packaging materials in which a plastic film as a base material, an aluminum foil as an oxygen and water vapor barrier layer, and a thermoplastic resin film for heat sealing are sequentially laminated. What has been printed on the entire surface of the bag to enhance the decorative effect has been widely used. However, a material in which a conventional aluminum foil is laminated cannot be used for a microwave oven. Therefore, in recent years, with the widespread use of microwave ovens in the home, the market for food packaging materials using packaging films made of flexible plastic films that have barrier properties that can be applied to microwave ovens is possible. doing.
The properties required for food packaging films include:
1. Excellent gas barrier properties such as moisture prevention, incense retention, oxidation prevention,
2. Sufficient strength and flexibility;
3. Heat and pressure sterilization can be applied,
and so on.
Conventionally, as a material that satisfies the above characteristics, a flexible plastic film is used as a base material, and metal oxides such as aluminum oxide, magnesium oxide, and silicon oxide are vapor-deposited on this surface, and another film is laminated on the vapor-deposited surface. JP-A-58-148759, JP-A-1-206036, JP-A-1-267036, and JP-A-2-34330 have proposed films.

  Recently, laminated packaging materials with ceramic layers, such as light-transmitting aluminum oxide vapor-deposited layers or silicon oxide vapor-deposited layers as oxygen and water vapor barrier films, have been used as materials for retort foods, and have excellent disposal and contents. It is used for packaging materials such as foods such as confectionery and pharmaceuticals other than materials for retort foods, taking advantage of the fact that it can be confirmed from the outside.

In order to realize a plastic film having gas barrier properties, physical film formation methods (PVD methods) such as induction heating method, resistance heating method, electron beam evaporation method, sputtering method, etc. Since it is easy to develop, it has been studied and put to practical use as a system that can be expected to exhibit high gas barrier properties using these methods. The PVD method is roughly divided into an evaporation method such as an induction heating method, a resistance heating method, and an electron beam evaporation method, and a sputtering method. The evaporation method has a high film formation speed but a dense film having a high gas barrier property. On the other hand, the sputtering method has a slow film formation rate, but can provide a dense film with high gas barrier properties. For this reason, in general, gas barrier films for flexible packaging materials often use vapor deposition, and large-area film formation using sputtering is often used for optical film applications that require precise film thickness control. The price per m ² is higher than the vapor deposition method. However, in recent years, there is a high demand for quality even in gas barrier films for soft packaging materials used for packaging materials for heat sterilization, and higher barrier properties have been demanded.

  Regarding the problem of incompatibility between the productivity and the gas barrier property, a pressure gradient type plasma gun is used as a material evaporation method as a means of taking the productivity between the vapor deposition method and the sputtering method and the gas barrier property between the vapor deposition method and the sputtering method. The vapor deposition method used as the above has been devised (Patent Document 1). In this method, the plasma emitted from the plasma gun is focused to the material by converging it using a magnetic field, etc., and the material is heated and evaporated. At the same time, the atoms and molecules being evaporated are emitted from the plasma gun. It is a method that can be activated by passing, and can enter a substrate with a higher kinetic energy than that at the time of evaporation to obtain a denser film than a normal vapor deposition method.

JP 2005-34831 A

  However, this method is less complicated because the material can be evaporated and activated by plasma at the same time, and it is advantageous in terms of apparatus cost. On the other hand, the material evaporation rate and the plasma density are uniquely determined. There is a problem that the evaporation rate and the plasma density for activation cannot be determined freely. For this reason, there is a problem that it is difficult to freely set the gas barrier property with respect to the film formation rate.

  In view of the above problems, the present invention can freely set the evaporation rate and plasma density of the material, can freely set the gas barrier property with respect to the film formation rate, and has excellent oxygen barrier property and water vapor barrier property, or is transparent. An object is to provide a packaging material for heat sterilization using a translucent gas barrier film.

In order to solve this problem, the invention described in claim 1 is a packaging material for pressure and heat sterilization in which a gas barrier film, an adhesive layer, a nylon film, an adhesive layer, and a heat-sealable resin film are laminated in this order. ,
The gas barrier film has a ceramic layer formed on a plastic film as an evaporation means by an electron beam evaporation method . In this case, any one of ICP plasma, helicon wave plasma, and holo cathode discharge is combined with the evaporation means. It is a packaging material for pressurization heating sterilization characterized by using.
According to a second aspect of the invention, between said ceramic layer and the nylon film, a packaging material for pressurizing and heating sterilization according to claim 1, characterized in that by forming an overcoat layer.
According to a third aspect of the present invention, the ceramic layer is made of any one of a silicon oxide film, a silicon nitride film, a silicon oxynitride film, an aluminum oxide film, an aluminum nitride film, an aluminum oxynitride film, and a magnesium oxide film. It is a packaging material for pressurization heating sterilization of Claim 1 or 2 .

  The packaging material for heat and pressure sterilization according to the present invention comprises a gas barrier film, an adhesive layer, a nylon film, an adhesive layer and a heat sealable resin laminated in this order, and the gas barrier film is vapor-deposited on the plastic film using vapor deposition means. A ceramic layer is formed by the above method, and in that case, a means for generating a high-density plasma is used in addition to the vapor deposition means, so that the evaporation rate of the material and the plasma density can be freely set. In addition, the gas barrier property with respect to the deposition rate can be set freely, and the oxygen barrier property and the water vapor barrier property are also excellent.

It is the block diagram which showed one Embodiment of the packaging material for pressurization heat sterilization of this invention. It is a schematic diagram of the film-forming apparatus used in order to produce the packaging material for pressurization heat sterilization of this invention.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a configuration diagram (cross-sectional view) showing an embodiment of a packaging material for heat sterilization of the present invention.
A ceramic layer 11 and an overcoat layer 12 are formed on the plastic film substrate 10, and a nylon film 14 is laminated on the overcoat layer 12 side via an adhesive layer 13. The heat-sealable resin film 16 is laminated through the adhesive layer 15.

  The plastic film substrate 10 is not particularly limited, and a known one can be used. For example, polyolefin (polyethylene, polypropylene, etc.), polyester (polyethylene terephthalate, polyethylene naphthalate, etc.), polyamide (nylon-6, nylon-66, etc.), polystyrene, ethylene vinyl alcohol, polyvinyl chloride, polyimide, polyvinyl alcohol, Polycarbonate, polyethersulfone, acrylic, cellulose-based (triacetyl cellulose, diacetyl cellulose, etc.) and the like are exemplified, but not particularly limited. In practice, it is desirable to select appropriately depending on the application and required physical properties, but it is not a limited example, but polyethylene terephthalate, polypropylene, nylon, etc. are easy to use for packaging medical supplies, drugs, foods, etc. . Moreover, although the base film thickness is not limited, about 6 to 200 μm is easy to use depending on the application.

  In addition, the surface of the plastic film substrate for barrier film production should be an anchor coat layer based on a resin material that improves adhesion and barrier degree, or a substrate that has been surface treated with plasma. Also good.

Examples of the ceramic layer 11 include a silicon oxide film, a silicon nitride film, a silicon oxynitride film, an aluminum oxide film, an aluminum nitride film, an aluminum oxynitride film, and a magnesium oxide film. The vapor deposition material used when vapor-depositing these is not particularly limited, and known materials can be used. For example, in the case of a silicon oxide film, silicon (Si), silicon monoxide (SiO), silicon dioxide (SiO ₂ ), or a mixture thereof can be used, but not limited thereto. Alternatively, a silicon oxide film may be obtained by using a reactive gas such as oxygen in combination with the deposition of the above materials.

  The overcoat layer 12 formed on the ceramic layer 11 is at least one metal represented by R1 (M-OR2) (where R1 and R2 are organic groups having 1 to 8 carbon atoms, and M is a metal atom). It is desirable to laminate a coating film containing a composition using alkoxide as a raw material on the ceramic layer 11. M is preferably Si, Al, Ti, etc., and particularly Si. Other water-soluble polymers may be mixed.

  The nylon film 14 may be a uniaxially stretched nylon film stretched in the tear direction, or a biaxially stretched nylon film of a polymer blend with an aromatic polyamide or the like.

  The heat-sealable resin film 16 can be composed of the same material as that conventionally used as a sealant for packaging materials, and uses polyethylene, polypropylene, ethylene-vinyl acetate copolymer, ionomer, or the like. I can do it.

  The plastic film substrate 10 having a water vapor and oxygen barrier property and the nylon film 14 are laminated through the adhesive layer 13, but it is preferable to use a urethane-based adhesive as the adhesive of the adhesive layer 13, and laminate it. As a method, lamination is preferably performed by a dry lamination method, a non-solvent lamination method, an extrusion lamination method, a knee lamb lamination method, or the like.

  The heat seal resin film 16 and the nylon film 14 are laminated through the adhesive layer 15, and it is preferable to use a urethane-based adhesive as the adhesive of the adhesive layer 15. Lamination is preferably performed by a solvent lamination method, an extrusion lamination method, a knee lamb lamination method, or the like.

  FIG. 2 is an example of a schematic view of a film forming apparatus for producing a gas barrier film retaining water vapor and oxygen barrier properties in the packaging material for heat sterilization of the present invention. In the vacuum chamber 20, the plastic film 21 is set on the unwinding roller 22, passes through the main drum 23 from the unwinding roller 22, and is wound on the winding roller 24. At this time, a ceramic layer is formed on the plastic film 21 in the main drum 23. The crucible 25 is filled with a material 26 for forming a ceramic layer. Further, a straight electron beam gun 27 is installed as a vapor deposition means. A reactive gas introduction pipe 30 is installed in the film forming chamber as a means for introducing the reactive gas. The material 26 heated by the electron beam becomes vapor and is deposited on the plastic film. The vapor at this time is indicated by vapor deposition particles 28, and high-density plasma for ion plating the vapor deposition particles is indicated by plasma 29.

  In FIG. 2, a straight electron beam gun 27 is installed as a means for heating the vapor deposition material 26 and the electron beam vapor deposition method is shown. As the vapor deposition means, a resistance heating method or The material may be evaporated by heating using a high frequency induction heating method or the like. The electron beam evaporation method may be a straight electron beam gun or a deflected electron beam gun, but a Pierce type flat cathode electron gun capable of supplying a large amount of electric power in order to develop a high film forming speed. However, it is not limited to this. The resistance heating method may be a method of directly resistance heating a crucible filled with a material, or may be a resistance heating method of feeding a metal wire to the resistance heating part. Both methods are required to have an apparatus configuration capable of exhibiting a high film formation rate.

  When depositing the material, a plasma is generated from a plasma source. When depositing at a high deposition rate, the number of vapor deposition particles is very large, so if it is not a method that can express a high plasma density, the number of particles that are converted into plasma is smaller than vapor deposition particles, and the film quality is improved. It is difficult to express changes to be made. For this reason, it is optimal to use any one of the ICP plasma method, the helicon wave plasma method, the microwave plasma method, and the holocathode discharge method as means for developing a high plasma density.

The packaging material for heat and pressure sterilization of the present invention preferably has a water vapor permeability of 1 g / m ² / day or less. Since the packaging material for pressure heat sterilization of this invention is comprised using the plastic film which formed the ceramic layer into a film using the high-density plasma, it is excellent in water vapor | steam barrier property.

Furthermore, the packaging material for heat and pressure sterilization of the present invention preferably has an oxygen permeability of 1 cc / m ² / day or less. Since the packaging material for pressure heat sterilization of this invention is comprised using the plastic film which formed the ceramic layer into a film using the high-density plasma, it is excellent in water vapor | steam barrier property.

Specific examples of the present invention are shown below. The following Example 3 is a reference example.

<Example 1>
Using the film forming apparatus shown in FIG. 2, an aluminum lump as material 26 is packed in a crucible 25, a straight electron beam gun 27 is used as a heating means, evaporated at a film forming rate of 100 nm / sec, and oxygen gas is supplied from a gas pipe 30. Then, an aluminum oxide thin film is deposited on the plastic film 21 by reactive vapor deposition. At this time, a PET film having a thickness of 12 μm was used as the plastic film 21 flowing from the unwinding roller 22 toward the winding roller 14, and a physical film thickness of 20 nm was formed. At this time, ion plating was performed using a holocathode arc discharge simultaneously with electron beam evaporation. The holocathode pipe of the holocathode discharge source was subjected to 70 sccm of argon to generate a discharge of 10 kW and ion plating. On the ceramic layer of the plastic film on which the ceramic layer was formed, an overcoat layer was formed by a microgravure method to produce a water vapor and oxygen barrier plastic film. This plastic film and a 70 μm thick nylon film were laminated by a dry lamination method using a urethane adhesive. Further, a propylene film having a thickness of 100 μm as a heat seal resin was laminated on the nylon film side by a dry lamination method using a urethane-based adhesive to produce a packaging material for pressure and heat sterilization.

<Example 2>
Using the film forming apparatus shown in FIG. 2, an aluminum lump as material 26 is packed in a crucible 25, a straight electron beam gun 27 is used as a heating means, evaporated at a film forming rate of 100 nm / sec, and oxygen gas is supplied from a gas pipe 30. Then, an aluminum oxide thin film is deposited on the plastic film 21 by reactive vapor deposition. At this time, a PET film having a thickness of 12 μm was used as the plastic film 21 flowing from the unwinding roller 22 toward the winding roller 14, and a physical film thickness of 20 nm was formed. At this time, ion plating was performed using ICP plasma simultaneously with electron beam evaporation. 10kW was applied to the 13.56 MHz power source that generated the ICP plasma, and the plasma was generated for ion plating. On the ceramic layer of the plastic film on which the ceramic layer was formed, an overcoat layer was formed by a microgravure method to produce a water vapor and oxygen barrier plastic film. This plastic film and a 70 μm thick nylon film were laminated by a dry lamination method using a urethane adhesive. Further, a propylene film having a thickness of 100 μm as a heat seal resin was laminated on the nylon film side by a dry lamination method using a urethane-based adhesive to produce a packaging material for pressure and heat sterilization.

<Example 3>
Using the film forming apparatus shown in FIG. 2, an aluminum lump as material 26 is packed in a crucible 25, a straight electron beam gun 27 is used as a heating means, evaporated at a film forming rate of 100 nm / sec, and oxygen gas is supplied from a gas pipe 30. Then, an aluminum oxide thin film is deposited on the plastic film 21 by reactive vapor deposition. At this time, a PET film having a thickness of 12 μm was used as the plastic film 21 flowing from the unwinding roller 22 toward the winding roller 14, and a physical film thickness of 20 nm was formed. At this time, ion plating was performed using microwave plasma simultaneously with electron beam evaporation. In generating the microwave plasma, 6 kW was applied to the 2.45 GHz microwave power source to generate the plasma. On the ceramic layer of the plastic film on which the ceramic layer was formed, an overcoat layer was formed by a microgravure method to produce a water vapor and oxygen barrier plastic film. This plastic film and a 70 μm thick nylon film were laminated by a dry lamination method using a urethane adhesive. Further, a propylene film having a thickness of 100 μm as a heat seal resin was laminated on the nylon film side by a dry lamination method using a urethane-based adhesive to produce a packaging material for pressure and heat sterilization.

<Comparative Example 1>
Using the film forming apparatus shown in FIG. 2, an aluminum lump as material 26 is packed in a crucible 25, a straight electron beam gun 27 is used as a heating means, evaporated at a film forming rate of 100 nm / sec, and oxygen gas is supplied from a gas pipe 30. Then, an aluminum oxide thin film is deposited on the plastic film 21 by reactive vapor deposition. At this time, a PET film having a thickness of 12 μm was used as the plastic film 21 flowing from the unwinding roller 22 toward the winding roller 14, and a physical film thickness of 20 nm was formed. On the ceramic layer of the plastic film on which the ceramic layer was formed, an overcoat layer was formed by a microgravure method to produce a water vapor and oxygen barrier plastic film. This plastic film and a 70 μm thick nylon film were laminated by a dry lamination method using a urethane adhesive. Further, a propylene film having a thickness of 100 μm as a heat seal resin was laminated on the nylon film side by a dry lamination method using a urethane-based adhesive to produce a packaging material for pressure and heat sterilization.

  About the created sample, water vapor permeability and oxygen permeability were measured by the following methods.

(Evaluation method)
The water vapor transmission rate (WVTR) was measured by the MOCON method. The measuring instrument used was MOCON PERMATRAN 3/33, which was measured at 40 ° C. and 90% Rh, and the oxygen permeability (OTR) was measured at 23 ° C. and 0% Rh by MOCON OX-TRAN 2/20.

  Table 1 shows the water vapor permeability and oxygen permeability of the samples prepared in Example 1, Example 2, Example 3, and Comparative Example 1.

  From the results in Table 1, the packaging material for pressure and heat sterilization produced using a plastic film in which a ceramic layer is formed using high-density plasma separately from the vapor deposition method at the time of vapor deposition is a plastic film that does not use high-density plasma. In comparison, results with high gas barrier properties were obtained.

  The packaging material for pressure and heat sterilization of the present invention has high transparency and high oxygen and water vapor barrier properties, and is optimal as, for example, a food packaging film.

DESCRIPTION OF SYMBOLS 10 ... Plastic film 11 ... Ceramic layer 12 ... Overcoat layer 13 ... Adhesive layer 14 ... Nylon film 15 ... Adhesive layer 16 ... Heat-sealable resin film 20 ... Vacuum chamber 21 ... Plastic film 22 ... Unwinding roller 23 ... Main drum 24 ... Winding roller 25 ... Crucible 26 ... Deposition material 27 ... Linear electron beam gun 28 ... -Vapor deposition particles 29 ... Plasma 30 ... Reactive gas introduction pipe

Claims (3)

A gas barrier film, an adhesive layer, a nylon film, an adhesive layer, and a heat-sealable resin film are laminated in this order for pressure and heat sterilization packaging materials,
The gas barrier film has a ceramic layer formed on a plastic film as an evaporation means by an electron beam evaporation method . In this case, any one of ICP plasma, helicon wave plasma, and holo cathode discharge is combined with the evaporation means. A packaging material for pressure and heat sterilization characterized by being used. The packaging material for heat and pressure sterilization according to claim 1 , wherein an overcoat layer is formed between the ceramic layer and the nylon film. 3. The additive according to claim 1, wherein the ceramic layer is formed of any one of a silicon oxide film, a silicon nitride film, a silicon oxynitride film, an aluminum oxide film, an aluminum nitride film, an aluminum oxynitride film, and a magnesium oxide film. Packaging material for pressure heat sterilization.

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