JP2008110507A - Packaging material for retort sterilization and its package - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a packaging material for retort sterilization which is used in a packaging field including food, non-food, medical supplies, and medical equipment, its packaging bag, in detail, especially, a retort-sterilizable packaging bag which is excellent in unsealing properties and impact resistance, inexpensive, and can be produced stably, and an applied film drying apparatus which dries the film applied/formed on a substrate being conveyed continuously. <P>SOLUTION: In the packaging material for retort sterilization, a gas-barrier base film and a coextrusion laminated film in which three layers made of surface and back polypropylene resin layers via an intermediate layer are laminated by a coextrusion shaping method are laminated through an adhesive. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a packaging material for retort sterilization used in the packaging field of foods, non-foods, pharmaceuticals, medical devices and the like, and a package thereof. In particular, the present invention relates to a packaging material for retort sterilization, which is not only excellent in openability and impact resistance, but also less likely to curl, can be efficiently and stably produced, and can be manufactured at low cost, and its package.

  Conventionally, packaging materials used for packaging foods, non-foods, pharmaceuticals, etc. have altered the contents of oxygen, water vapor, and other contents that permeate the packaging material in order to suppress the alteration of the contents and maintain their functions and properties. It is necessary to prevent the influence of the gas to be generated, and it is required to have a gas barrier property for blocking these gases (gases).

  In order to prevent the contents from being altered, retort sterilization or the like is performed in which the contents are hermetically packaged with a packaging material and then heated or heated and pressurized.

  The packaging material constituting the packaging bag for sterilization of retort is mainly composed of a plastic film and includes metal foil. For example, from the outside, polyethylene terephthalate (PET) / aluminum foil (Al foil) / unstretched polypropylene (CPP) ); Stretched polypropylene (OPP) / Al foil / CPP; stretched nylon (ONy) / Al foil / CPP; PET / Al foil / nylon (Ny) / CPP; OPP / Al foil / Ny / CPP; ONy / Al foil / A structure such as Ny / CPP is in practical use. A two-component curable urethane adhesive is used for laminating each layer.

  The packaging material uses unstretched polypropylene (CPP) as a sealant to withstand the wet heat of the retort. This unstretched polypropylene (CPP) is usually excellent in terms of heat resistance and strength. The unstretched polypropylene (CPP) had a shrinkage ratio of 1 to 5% in the longitudinal direction and / or the transverse direction when heated at 120 ° C. for 20 minutes.

  The aluminum foil used in the above conventional packaging material is excellent as a barrier layer that does not allow gas such as oxygen and water vapor to permeate, and the conventional packaging material uses aluminum foil for the purpose of this barrier property. Yes. However, since aluminum foil is a metal, there is a problem that it is not transparent and the contents of the pouch cannot be seen through. Moreover, since it was metal foil, there existed a problem that a pouch could not be heated with a microwave oven.

  Many materials have been proposed in which a thin film of an inorganic substance is formed on a plastic film as a material that does not allow gas such as oxygen and water vapor to pass through while allowing such contents to be seen through or heated by a microwave oven. For example, a barrier material in which silicon oxide is formed to a thickness of 1000 mm on a film such as polyethylene terephthalate or polypropylene by vacuum deposition is shown.

  Further, many retort sterilization packaging materials and packaging bags in which a two-layer two-layer coextruded film is laminated on a barrier material having a thin film formed by vacuum deposition have been proposed. For example, a retort sterilization packaging bag is required to have impact resistance and easy opening, and a retort sterilization packaging bag having properties of both impact resistance and easy opening has been proposed. (For example, refer to Patent Document 1).

This packaging bag is a packaging bag capable of retort sterilization comprising a laminated film in which a base material layer, an intermediate layer, and a sealant layer are sequentially laminated. And the base material layer and the intermediate | middle layer are laminated | stacked by the coextrusion molding method, and are laminated | stacked with the sealant layer through the adhesive agent. In addition, an unstretched polypropylene film made of an ethylene / propylene / block copolymer resin is used for the sealant layer.

  In addition, the retort sterilization packaging material that includes a plastic film with a thin film layer of inorganic material and a sealant layer does not cause cracks in the thin film of inorganic material, and does not cause whitening and has excellent transparency, for retort sterilization Packaging materials are also known. (For example, refer to Patent Document 2).

  The packaging material for retort sterilization includes a barrier film in which a thin film layer of an inorganic substance is formed on a plastic film, and a sealant layer made of unstretched polypropylene having a shrinkage rate of 0.5% or less and containing no rubber component. It is the packaging material for retort sterilization laminated | stacked with the adhesive agent. It is described that silicon oxide is preferable as the inorganic substance.

Prior art documents are shown below.
JP 11-79191 A JP-A-6-179473

  By the way, the packaging bag of patent document 1 is formed from the laminated film by which the base material layer and the intermediate | middle layer are laminated | stacked by the coextrusion molding method, and the intermediate | middle layer surface and the sealant layer were bonded together through the adhesive agent. And the material of the film of each layer is laminated | stacked by the different thing altogether.

  As described above, the laminated film is formed from a coextruded laminated film in which the base material layer and the intermediate layer are composed of two types and two layers.

  For this reason, there is a problem that curling occurs in the laminated film as well as curling in the lamination with the sealant layer. And when making this laminated film with a bag making machine or the like, there is a problem that the processability is poor, the working efficiency is remarkably lowered, and at the same time, the bag formed is curled.

  Moreover, the packaging material for retort sterilization of patent document 2 is formed from the plastic film in which the printing base material layer and the thin film layer of an inorganic substance are formed, and the laminated film in which the sealant layer is bonded together through the adhesive agent. . And the thing from which all the materials of the film of each layer differ is laminated | stacked.

  Moreover, when producing the said laminated | multilayer film, it bonds together by dry lamination etc. In the case of bonding, a sealant layer is laminated after bonding a printing substrate layer and a plastic film on which a thin film layer of an inorganic substance is formed. Alternatively, after the plastic film on which the sealant layer and the thin film layer of the inorganic material are formed is bonded, the printing substrate layer is laminated. For this reason, at least two times of bonding are required.

  In addition, when performing the second bonding operation, there is a problem that curling occurs as in Patent Document 1, and curling also occurs in the laminated film. And when making this laminated film with a bag making machine or the like, there is a problem that the processability is poor, the working efficiency is remarkably lowered, and at the same time, the bag formed is curled.

  The present invention has been made in view of the above-described conventional problems, and the problem is that the bonding process is reduced and curling is prevented, and the bonding operation is stable. An object of the present invention is to provide a packaging material for retort sterilization that can be efficiently and inexpensively produced, and a packaging body thereof.

In order to solve the above problems, the invention according to claim 1 of the present invention provides:
A gas-extrusion base film and a co-extrusion laminated film in which three layers each comprising a polypropylene resin layer were laminated by a co-extrusion molding method via a polyamide resin layer (intermediate layer) were laminated via an adhesive. This is a packaging material for retort sterilization.

Next, the invention according to claim 2 of the present invention is as follows:
2. The packaging material for retort sterilization according to claim 1, wherein the coextruded laminated film has a two-layer / three-layer structure.

Next, the invention according to claim 3 of the present invention is
3. The packaging material for retort sterilization according to claim 1, wherein the gas barrier base film is made of a transparent vapor-deposited film through a base film and an adhesive.

Next, the invention according to claim 4 of the present invention is
The packaging material for retort sterilization according to claim 1 or 2, wherein the gas barrier base film is made of an aluminum foil with a base film and an adhesive interposed therebetween.

Next, the invention according to claim 5 of the present invention is
The packaging material for retort sterilization according to any one of claims 1 to 4, wherein a printed layer is formed on the back side surface of the base film.

Next, the invention according to claim 6 of the present invention is
A packaging material for retort sterilization using the packaging material for retort sterilization according to any one of claims 1 to 5 in a bag shape.

Next, the invention according to claim 7 of the present invention is
A packaging material for retort sterilization using the packaging material for retort sterilization according to any one of claims 1 to 5 in a container shape.

  Since the packaging material for retort sterilization of the present invention and the package thereof have the above-described configuration, the laminated packaging material is difficult to curl at the time of the operation process such as bonding, and the bonding operation is stable. Efficient and smooth. And production efficiency improves and manufacturing cost can be reduced.

  Furthermore, since the gas barrier substrate film and the coextruded film of 2 types and 3 layers are laminated, not only curling can be prevented but also the bonding process and the like can be reduced. And it can be manufactured inexpensively with uniform and stable quality.

  In addition, since the packaging material for retort sterilization according to the present invention hardly causes curling or the like, it is easy to carry out bag making and molding, and can be stably and efficiently produced. And the package which is uniform and excellent in quality can be manufactured at low cost by a known manufacturing processing machine or the like.

  A packaging material for retort sterilization and a packaging body thereof according to the present invention will be described in detail below with reference to the drawings.

  FIG. 1 is a cross-sectional view showing a cross-section of one embodiment of the configuration of the packaging material for retort sterilization of the present invention.

  As shown in FIG. 1, in the packaging material for retort sterilization of the present invention, a coextrusion laminated film 4 and a gas barrier base film 9 are laminated via an adhesive.

The gas barrier base film 9 has a general formula R′Si (OR) ₃ (R ′: alkyl group, vinyl group, glycidoxypropyl group, R, etc.) on at least one side of the base film 5 made of a transparent plastic material. A transparent primer layer 6 composed of a trifunctional organosilane that can be represented by: an alkyl group or the like, or a hydrolyzate of the organosilane, and a composite of an acrylic polyol and an isocyanate compound, an inorganic oxide 7 having a thickness of 5 to 300 nm, An aqueous solution or a water / alcohol mixed solution containing at least one of a water-soluble polymer and (a) one or more metal alkoxides and hydrolysates thereof, or (b) tin chloride is mainly used on the inorganic oxide 7. A gas barrier coating layer 8 formed by applying a coating agent and heating and drying is sequentially laminated.

  The gas barrier coating layer 8 is not necessarily provided, and can be provided according to the required quality.

  On the other hand, the coextruded film laminate 4 is a two-type three-layer formed by laminating a polypropylene resin layer 3 (bonding side), a polyamide resin layer 2 and a polypropylene resin layer 1 (sealant side) by a coextrusion molding method. This is a coextruded laminated film 4.

  The polypropylene resin layer 1 on the sealant side of the coextruded laminated film 4 must be a heat-sealing resin layer, and of course requires hot water that can be sterilized by retort. For this reason, the unstretched polypropylene film (CPP) comprised by ethylene propylene block copolymer resin can be used conveniently. Among them, an ethylene / propylene / block copolymer resin in which the ethylene content of the crystalline polymer component constituting the block polypropylene is 5% by weight or more and the ethylene content of the rubber component is 40% by weight or more. CPP having a melting point of 140 ° C. or higher in DSC can be more preferably used.

The base film 5 of the gas barrier base film 9 is a transparent plastic material, and is preferably a transparent film in order to make use of the transparency of the deposited thin film layer. For example, polyester films such as polyethylene terephthalate and polyethylene naphthalate, polyolefin films such as polyethylene and polypropylene, polystyrene films, polyamide films, polyvinyl chloride films, polycarbonate films, polyacrylonitrile films, polyimide films, etc. Either stretching may be used, and those having mechanical strength and dimensional stability are preferred. These are processed into a film and used. In particular, polyethylene terephthalate arbitrarily stretched in the biaxial direction is preferably used.

  Further, various well-known additives and stabilizers such as antistatic agents, anti-ultraviolet agents, plasticizers, lubricants and the like may be used on the surface of the base film 5 to improve the adhesion to the thin film. Therefore, corona treatment, low temperature plasma treatment, and ion bombardment treatment may be performed as pretreatment, and chemical treatment, solvent treatment, and the like may be performed.

The thickness of the base film 5 is not particularly limited, but is suitable as a packaging material, may be laminated with other layers, a transparent primer layer 6 and an evaporated thin film layer 7 made of an inorganic oxide. In consideration of the workability when forming the gas barrier coating layer 8, it is practically in the range of 3 to 200 μm and preferably 6 to 30 μm depending on the application.

  In consideration of mass productivity, it is desirable to use a long film so that each layer can be formed continuously.

  The transparent primer layer 6 of the gas barrier base film 9 is provided on the base film 5 made of a transparent plastic material, and improves the adhesion between the base film 5 and the deposited thin film layer 7 made of an inorganic oxide. The purpose is to prevent the occurrence of delamination after boil sterilization, retort sterilization, and autoclave sterilization.

  In order to achieve the above object, a composite of trifunctional organosilane or a hydrolyzate thereof with acrylic polyol and isocyanate compound can be used as a primer resin.

Furthermore, the composite which comprises the transparent primer layer 6 is demonstrated in detail. Examples of the trifunctional organosilane include general formula R′Si (OR) ₃ such as ethyltrimethoxysilane, vinyltrimethoxysilane, glycidoxypropyltrimethoxysilane (where R ′ is an alkyl group, vinyl group, glycidoxypropyl group, etc.) , R is an alkyl group or the like), or a hydrolyzate thereof. Of these, glycidoxytrimethoxysilane, epoxycyclohexylethyltrimethoxysilane, and the like in which an epoxy group is contained in R ′ are particularly preferable. The method for obtaining the hydrolyzate can be obtained by a known method such as a method of performing hydrolysis by directly adding an acid, alkali or the like to the trifunctional organosilane.

The thickness of the transparent primer layer 6 is not particularly limited as long as a uniform coating film can be formed, but is generally preferably in the range of 0.01 to 2 μm. When the thickness is less than 0.01 μm, it is difficult to obtain a uniform coating film, and the adhesion may be lowered. On the other hand, when the thickness exceeds 2 μm, the coating film cannot be kept flexible because it is thick, and the coating film may be cracked due to external factors, which is not preferable. Particularly preferred is a range of 0.05 to 0.5 μm.

  As a method for forming the transparent primer layer 6, for example, a known printing method such as an offset printing method, a gravure printing method, a silk screen printing method, or a known coating method such as roll coating, knife edge coating, or gravure coating is used. Can do. About drying conditions, generally used conditions may be used.

The vapor deposition thin film layer 7 made of an inorganic oxide is made of a vapor deposition film of an inorganic oxide such as aluminum oxide, silicon oxide, tin oxide, magnesium oxide, or a mixture thereof. And what is necessary is just to have transparency and gas barrier properties, such as oxygen and water vapor | steam. Among these, aluminum oxide and silicon oxide are particularly preferable. However, the vapor-deposited thin film layer 7 in the present invention is not limited to the inorganic oxide described above, and any material that meets the above conditions can be used.

  The optimum thickness of the vapor-deposited thin film layer 7 varies depending on the type and configuration of the inorganic compound to be used, but generally it is preferably in the range of 5 to 300 nm, and the value is appropriately selected. However, if the film thickness is less than 5 nm, a uniform film may not be obtained or the film thickness may not be sufficient, and the function as a gas barrier material may not be sufficiently achieved.

On the other hand, when the film thickness exceeds 300 nm, flexibility cannot be maintained in the thin film, and the thin film may be cracked due to external factors such as bending and pulling after the film formation. The thickness of the deposited thin film layer 3 is preferably in the range of 10 to 150 nm.

  There are various methods for forming the vapor-deposited thin film layer 7 made of an inorganic oxide on the transparent primer layer 6, and it can be formed by a normal vacuum vapor deposition method, but other thin film forming methods such as sputtering and ion plating. Alternatively, a plasma vapor deposition method (CVD) or the like can be used. However, considering productivity, the vacuum deposition method is the best at present.

  Moreover, as a heating means of the vacuum evaporation apparatus by the vacuum evaporation method, an electron beam heating method, a resistance heating method, and an induction heating method are preferable. In order to improve the adhesion between the thin film and the substrate and the denseness of the thin film, the plasma assist method is used. Alternatively, an ion beam assist method can be used. In addition, in order to increase the transparency of the deposited film, it is possible to carry out reactive deposition by blowing oxygen gas or the like during deposition.

  The gas barrier coating layer 8 is provided on the vapor-deposited thin film layer 7 made of an inorganic oxide in order to provide a gas barrier property as high as that of an aluminum foil depending on the required quality.

The gas barrier coating layer 8 is mainly composed of an aqueous solution or water / alcohol mixed solution containing at least one of a water-soluble polymer and (a) one or more metal alkoxides and hydrolysates or (b) tin chloride. It is formed using a coating agent. Mineralize a solution in which water-soluble polymer and tin chloride are dissolved in an aqueous (water or water / alcohol mixed) solvent, or a solution in which metal alkoxide is directly or hydrolyzed beforehand. The deposited thin film layer 7 made of oxide is formed by coating and heating and drying.

Next, the coextruded laminated film 4 used in the present invention is formed and laminated by a common T-die method or a coextrusion molding method of an inflation method. Then, although not shown in the drawing, the ethylene-propylene copolymer resin layers 1 and 3 or the polypropylene resin layers 1 and 3 are formed on the front side surface and the back side surface of the polyamide resin layer 2 through the adhesive resin layer. ing.

  Examples of the material of the ethylene-propylene copolymer resin layers 1 and 3 constituting the coextruded laminated film 4 include crystalline polypropylene resins such as ethylene-propylene block copolymers and ethylene-propylene random copolymers, and mixtures thereof. Is used. The ethylene content of the ethylene-propylene block copolymer and ethylene-propylene random copolymer is not particularly limited, but is usually 20% by weight or less. The melt flow rate (JIS K-7210, 230 ° C., 2.16 kg load) is not particularly limited, but is usually in the range of 0.01 to 100 g / 10 minutes.

  The polypropylene resin layers 1 and 3 are provided as a sealant layer as a heat bonding layer when forming a molded body such as a bag as a packaging material. The material is not particularly limited as long as it functions as a sealant. For example, a propylene homopolymer, an ethylene-propylene block copolymer, or an ethylene-propylene random copolymer is used. As thickness, the range of 10-200 micrometers is desirable. If it is less than 10 μm, sufficient strength as a packaging material cannot be obtained. If it exceeds 200 μm, it is economically disadvantageous.

  Moreover, as a raw material of the polyamide-type resin layer 2 which comprises the coextrusion laminated | multilayer film 4, if it is a polyamide-type resin, it will not specifically limit, Any of homopolyamide, a copolyamide, or these mixtures can be used.

For example, specific examples include polycaproamide (nylon 6), poly-ω-aminoheptanoic acid (nylon 7), poly-9-aminononanoic acid (nylon 9), polyundecanamide (nylon 11), polylaurin lactam ( Nylon 12), polyethylene diamine adipamide (nylon 2, 6), polytetramethylene adipamide (nylon 4, 6), polyhexamethylene didipamide (nylon 6, 6), polyhexamethylene sebacamide (nylon) 6,10), polyhexamethylene dodecamide (nylon 6,12), polyoctamethylene adipamide (nylon 8,6), polydecamethylene adipamide (nylon 10,6), polydecamethylene sebamide ( Nylon 10,10), polydodecamethylene dodecamide (nylon 12,12), metal Diamine -6 nylon (MXD6) and the like.

  In the above-mentioned base layer-constituting resin, other additives such as plasticizers, heat stabilizers, ultraviolet absorbers, antioxidants, antistatic agents, lubricants, antiblocking agents, and other resins are appropriately added as necessary. It is also possible to blend.

  Examples of the material constituting the adhesive resin layer include a vinyl acetate group, an acrylic group, a methacryl group, an acrylate group, a methyl methacrylate group, a maleic anhydride group, a glycidyl methacrylate group, and a metal ionization group of methacrylic acid. A monomer having a polar functional group that gives an adhesive function such as ethylene and propylene is copolymerized under high pressure to form a random copolymer, or ethylene, propylene, or two or more kinds of α -A polyolefin group resin having adhesive properties by using a monomer group having the above functional group in the olefin copolymer as a graft copolymer by a catalytic polymerization method or a light / radiation polymerization method is used.

Lamination of the gas barrier substrate film 9 and the coextruded laminate film 4 obtained above is performed by depositing the vapor barrier layer surface of the gas barrier substrate film 9 (when the gas barrier coating layer is provided, the gas barrier coating layer surface or when the printing layer is provided). Is a printing layer surface) and the ethylene-propylene copolymer resin layer 3 or the polypropylene resin layer 3 of the coextruded laminated film 4 are laminated via an adhesive layer 30.

As the adhesion / laminating method, for example, adhesion by a dry lamination method using a reactive curable adhesive made of polyurethane resin, acrylic resin, polyester resin, epoxy resin, or a copolymer resin of these resins. Can be stacked. The application amount of the adhesive may be applied and formed by a known application means such as a gravure coating method in the range of 1.0 to 5.0 g / m ² in terms of solid content.

  In addition, it is also possible to laminate | stack other layers, such as the printing layer 11 as shown in FIG. The printing layer 11 is formed for practical use as a package or the like, and conventionally used ink binder resins such as urethane, acrylic, nitrocellulose, rubber, and vinyl chloride. In addition, various layers such as various pigments, extender pigments and additives such as plasticizers, desiccants, stabilizers, and the like are formed, and characters, pictures, and the like are formed. As the formation method, for example, a known printing method such as an offset printing method, a gravure printing method, a flexographic printing method, a silk screen printing method, or a known coating method such as a roll coating, a knife edge coating, or a gravure coating is used. be able to. The thickness may be 0.1 to 2.0 μm.

  Next, FIG. 3 is a cross-sectional view showing a cross section of still another embodiment of the configuration of the packaging material for retort sterilization of the present invention.

  As shown in FIG. 3, in the packaging material for retort sterilization of the present invention, a coextruded laminated film 4 and a gas barrier base film 13 are laminated via an adhesive 10.

The gas barrier base film 13 is formed by laminating an aluminum foil 12 with an adhesive 10 on at least one surface of a base film 5 made of a plastic material. The thickness of the aluminum foil 12 needs to be 6 to 20 μm in order to ensure processability and prevent oxygen from entering.

  When the thickness is less than 6 μm, the aluminum foil 12 is liable to break during bonding (laminating) processing and packaging (bag making, container molding) processing, and pinholes are generated even when the foil does not break. Because it is easy, the danger of oxygen increases.

  On the other hand, when the thickness exceeds 20 μm, neither the effect of improving the breakage during processing nor the effect of preventing the occurrence of pinholes is particularly improved, so the total thickness of the laminate is simply increased, the weight increases and the cost increases. It is desirable to avoid it.

  Moreover, as a material of the aluminum foil 12, an aluminum-iron alloy (soft material) is used. It is desirable that the iron content is 0.3 to 9.0%, preferably 0.7 to 2.0%.

  When the iron content is less than 0.3%, the effect of preventing the occurrence of pinholes is not recognized, and when the iron content of the aluminum exceeds 9.0%, flexibility as aluminum is not achieved. It is obstructed and the processability of the laminate is deteriorated.

  In addition, aluminum produced by cold rolling changes its flexibility, waist strength and hardness under annealing (so-called annealing treatment) conditions, but aluminum is slightly more than the so-called hard-treated product that is not annealed. Alternatively, flexible aluminum that has been completely annealed is preferred.

  What is necessary is just to select suitably the softness | flexibility of the said aluminum, the intensity | strength of hardness, the degree of hardness, ie, the conditions of annealing, according to workability (bag making of a retort sterilization packaging body, container processing).

  For example, in order to prevent wrinkles and pinholes, it is desirable to use flexible aluminum annealed according to the degree of processing.

  Next, the retort sterilization packaging material of the present invention is usually printed with a pattern or the like. The formation position of the printing layer 11 is arbitrary, but when applied to food packaging, the printing layer 11 is formed on the inner surface of the base film 5 made of a plastic material as shown in FIG. And it is desirable that the printed layer 11 is protected by a plastic film or the like so as not to come into contact with food or other packaging.

  The printing layer 11 is formed and selected as appropriate by a gravure printing method, a flexographic printing method, a screen printing method, or the like.

  Further, the base film 5 and the aluminum foil 12 of the gas barrier base film 13 of the packaging material for retort sterilization of the present invention, the aluminum foil 12 and the coextruded laminated film 4 are formed by a known dry lamination method using a urethane-based adhesive. Laminated.

  In the packaging material for retort sterilization obtained as described above, the thermocompression bonding method, the high-frequency heating method, and the ultrasonic wave that are generally used so that the outer surface (seal side) of the coextruded laminated film 4 becomes the inner surface. A bag-like package 20 as shown in FIG. 5 is produced using a bag-making machine such as an adhesive method.

  The type of the bag-shaped package may be a bag-shaped package 20 formed by any bag-making method such as a three-side seal bag, a four-side seal bag, a pillow packaging bag, a joint seal bag, a standing bag, or a boat bottom bag. .

  Further, a container-like package 30 as shown in FIG. 6 is produced by using a vacuum molding machine, a pressure molding machine or a deep drawing machine using the packaging material for retort sterilization.

  Hereinafter, the present invention will be described in more detail with reference to specific examples, but the present invention is not limited thereto.

<Example 1>
A film having a thickness of 12 μm made of GL-ARH (manufactured by Toppan Printing Co., Ltd.) was used as the gas barrier substrate film. And the printing layer was formed in the inner surface with the urethane type gravure ink (made by Toyo Ink Manufacturing Co., Ltd.).

  Next, a two-kind three-layer film (manufactured by Tamapoly Co., Ltd.) having a total thickness of 100 μm and having a polypropylene resin layer formed on the front and back surfaces of the polyamide resin layer was used as a coextruded laminated film. The printed layer surface of the gas barrier substrate film and the polypropylene resin layer of the coextruded laminated film were laminated with an ester adhesive (manufactured by Mitsui Chemicals) to produce a packaging material for retort sterilization.

  Next, a three-side sealed bag-shaped package having a width of 130 mm, a height of 160 mm, and a seal width of 8 mm was produced using the retort sterilization packaging material produced above.

<Comparative Example 1>
Two types of co-extruded laminated films: a 20 μm polypropylene resin layer through a 5 μm adhesive layer on the front side of a 10 μm polyamide resin layer and a 60 μm polypropylene resin layer through a 5 μm adhesive layer on the back side A two-layer film was prepared. And the bag-shaped package body was produced like Example 1 using the film.

<Evaluation results>
The productivity, adhesive odor, retort resistance, seal strength, drop resistance, pressure resistance, and package manufacturing cost in Example 1 and Comparative Example 1 were comparatively evaluated. The results are shown in Table 1.

表１は実施例１と比較例１における生産性、接着剤臭、レトルト耐性、シール強度、落下耐性、耐圧強度、包装体製造原価を比較評価結果を示す。

Table 1 shows the results of comparative evaluation of productivity, adhesive odor, retort resistance, seal strength, drop resistance, pressure resistance, and package manufacturing cost in Example 1 and Comparative Example 1.

  The retort sterilization packaging material and the package thereof according to the present invention are less likely to curl and can be produced efficiently, and at the same time, a retort sterilization packaging material and package with excellent quality can be produced. And it is a wonderful invention that can be used for precision equipment members in the packaging field.

It is sectional drawing which shows the cross section of one Example of a structure of the packaging material for retort sterilization of this invention. It is sectional drawing which shows the cross section of another Example of the structure of the packaging material for retort sterilization of this invention. It is sectional drawing which shows the cross section of another Example of the structure of the packaging material for retort sterilization of this invention. It is sectional drawing which shows the cross section of another one Example of the structure of the packaging material for retort sterilization of this invention. It is the schematic which shows the outline of one Example of the package formed using the packaging material for retort sterilization of this invention. It is sectional drawing which shows the cross section of another Example of the package formed using the packaging material for retort sterilization of this invention. It is explanatory drawing in order to demonstrate.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Polypropylene-type resin layer or ethylene-propylene copolymer resin layer 2 ... Polyamide-type resin layer or ethylene-propylene copolymer resin layer 3 ... Polypropylene-type resin layer 4 ... Coextrusion laminated film 5 ... Base film 6 ... Transparent Primer layer 7 ... Deposition thin film layer made of inorganic oxide 8 ... Gas barrier coating layer 9 ... Gas barrier substrate film 10 ... Adhesive layer 11 ... Printing layer 12 ... Aluminum foil 13 ... Gas barrier substrate film 20 ... Bag-shaped Package 30 ... Container-shaped package

Claims (7)

  A gas-extrusion base film and a co-extrusion laminated film in which three layers each comprising a polypropylene resin layer were laminated by a co-extrusion molding method via a polyamide resin layer (intermediate layer) were laminated via an adhesive. A packaging material for retort sterilization.   The packaging material for retort sterilization according to claim 1, wherein the coextruded laminated film has a two-layer / three-layer structure.   The packaging material for retort sterilization according to claim 1 or 2, wherein the gas barrier base film is made of a transparent vapor-deposited film through a base film and an adhesive.   The packaging material for retort sterilization according to claim 1 or 2, wherein the gas barrier substrate film is made of an aluminum foil via a substrate film and an adhesive.   The packaging material for retort sterilization of any one of Claims 1 thru | or 4 by which the printing layer is formed in the back side surface of the said base film.   A packaging material for retort sterilization using the packaging material for retort sterilization according to any one of claims 1 to 5 in a bag shape.   A packaging material for retort sterilization using the packaging material for retort sterilization according to any one of claims 1 to 5 in a container shape.

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