WO2020196226A1

WO2020196226A1 - Heat-resistant packaging bag and method for manufacturing same

Info

Publication number: WO2020196226A1
Application number: PCT/JP2020/012208
Authority: WO
Inventors: 廣田　宗久; 山田　俊樹; 源英畠; 連松▲崎▼; 村上　恵喜; 厚深堀
Original assignee: 東洋製罐株式会社
Priority date: 2019-03-25
Filing date: 2020-03-19
Publication date: 2020-10-01
Also published as: JPWO2020196226A1

Abstract

The heat-resistant packaging bag according to the present invention comprises a multilayer film having at least a substrate layer formed of a polyester resin, and a polyester resin-based functional resin layer adjacent to the substrate layer, each of the substrate layer and the functional resin layer being formed of a co-extruded laminate film, to thus include a layer having properties required from a packaging bag. The present invention also reduces the number of laminates, to lead to excellent productivity, economic efficiency, and flavors.

Description

Heat-resistant packaging bag and its manufacturing method

The present invention relates to a heat-resistant packaging bag and a method for manufacturing the same. More specifically, the present invention comprises a multilayer film having a small number of laminating times and a reduced amount of adhesive used, and is excellent in productivity and flavor. The packaging bag and its manufacturing method.

Packaging bags containing food and drink have heat resistance that can be used for heat sterilization such as boil sterilization and retort sterilization, or heat cooking such as water bath and microwave oven heating, and impact resistance that can withstand drop impacts. Alternatively, it is formed of a multilayer film (laminated body) formed by laminating layers made of various materials in order to satisfy required performance such as barrier properties.
For example, Patent Document 1 below describes biaxially stretched polyethylene terephthalate (hereinafter, may be referred to as “PET”)-based film and polybutylene terephthalate (hereinafter, “PET”) in order from the outer surface in order to prevent holes due to microwave heating. A packaging bag made of a laminate made of a film (sometimes called PBT) and a thermosetting resin layer has been proposed.

Further, Patent Document 2 below includes a laminate including an outer surface and an inner surface, and a sealing portion for joining the inner surfaces of the laminate, and the laminate is a base material / adhesive in order from the outer surface side to the inner surface side. Layer / sealant layer, substrate / printing layer / adhesive layer / sealant layer, substrate / transparent gas barrier layer / printing layer / adhesive layer / sealant layer, or substrate / transparent gas barrier layer / adhesive layer / sealant layer, The base material comprises 51% by mass or more of polybutylene terephthalate, the adhesive layer contains a cured product of a polyol and an aliphatic isocyanate compound, and the aliphatic isocyanate with respect to the hydroxy group of the polyol. Bags have been proposed in which the isocyanate group of the compound has a molar ratio of 3.5 or more.

Japanese Unexamined Patent Publication No. 2006-143223 Japanese Unexamined Patent Publication No. 2018-58357

In the invention described in Patent Document 1, a laminated body mainly composed of PET film and PBT film having excellent heat resistance is used, but since it is laminated via an adhesive layer, it is a thermosetting resin. Two laminating steps are required to form a three-layered laminate including the layers. Further, as the number of layers of the laminated body increases, the number of laminations increases, such as providing a barrier layer to improve the barrier property of the packaging bag. Therefore, the laminating method by film laminating using an adhesive is inferior in productivity and economy. .. Further, as the number of adhesive layers increases, the amount of adhesive used also increases, so that not only the problems of productivity and economy but also the influence on the flavor of the contents are concerned.

Further, in the case of a bag having a print layer as in Patent Document 2, the print layer is formed inside the laminate in order to protect the print layer, but the print layer is an inner layer (sealant layer). If it is close to, the printing ink may impair the flavor of the contents. In order to solve such a problem, it is conceivable to form a barrier layer between the printing layer and the inner layer (sealant layer), but as described above, as the number of layers increases, the number of laminations increases, and so on. In terms of productivity and economy, we are still not fully satisfied.

Therefore, an object of the present invention is to provide a layer having the performance required for a packaging bag and to use a multilayer film having a layer structure capable of reducing the number of times of laminating, which has excellent heat resistance in productivity, economy and flavor. To provide a packaging bag.
Another object of the present invention is to provide a manufacturing method for efficiently manufacturing a multilayer film having a layer having a performance required for a packaging bag with a small number of laminating times to obtain a packaging bag.

According to the present invention, the base material comprises a base material layer made of a polyester resin, a functional resin layer based on a polyester resin adjacent to the base material layer, a printing layer, and a multilayer film having at least a top coat layer. Provided is a heat-resistant packaging bag characterized in that the layer and the functional resin layer are laminated films by coextrusion.

In the heat-resistant packaging bag of the present invention,
1. 1. That the multilayer film has a printing layer,
2. 2. The functional resin layer is at least one layer of a barrier resin layer, a heat-sealing resin layer, an oxygen-absorbing resin layer, an easily-openable resin layer, and an impact-resistant resin layer.
3. 3. The functional resin layer is a thermosetting resin layer, and a barrier layer composed of a vapor-deposited layer or a coating layer is formed on the base material layer.
4. The functional resin layer is a barrier resin layer composed of a polyester resin layer having a barrier layer composed of a vapor deposition layer or a coating layer, and the base material layer and the polyester resin layer are laminated films by coextrusion.
5. The heat-sealable resin layer is formed on one surface of the base material layer, and any one of the oxygen-absorbing resin layer, the easily-openable resin layer, and the impact-resistant resin layer is formed on the other surface. The three layers of the heat-sealing resin layer, the base material layer, the oxygen-absorbing resin layer, the easily-openable resin layer, and the impact-resistant resin layer are coextruded. Being a laminated film,
6. The functional resin layer is any one of the barrier resin layer, the oxygen absorbing resin layer, the easily openable resin layer, and the impact resistant resin layer, and the functional resin of the base material layer. A thermosetting layer made of polyolefin is formed via an adhesive on the surface opposite to the surface adjacent to the layers.
7. The print layer is formed on the outer surface side of the base material layer, and the top coat layer is formed on the outer surface side of the print layer.
Is preferable.

According to the present invention, a laminated film composed of a base material layer made of a polyester resin and a functional resin layer based on a polyester resin is formed by coextrusion lamination, and an adhesive is applied to the base material layer side of the laminated film. A multilayer film formed by forming a heat-sealing layer made of polyolefin, forming a printing layer on the functional resin layer side of the laminated film, and then forming a top coat layer on the printing layer. Provided is a method for producing a heat-resistant packaging bag, which comprises superimposing and heat-sealing heat-sealing layers made of polyolefin so as to be on the inner surface.
According to the present invention, a laminated film composed of a heat-sealing resin layer made of a polyester resin, a base material layer made of a polyester resin, and a functional resin layer based on a polyester resin is further formed by coextrusion laminating, and the laminated film is formed. After forming a print layer on the functional resin layer side of the film, a multilayer film formed by forming a top coat layer on the print layer is laminated so that the heat-sealable resin layers are on the inner surface. Provided is a method for producing a heat-resistant packaging bag, which comprises making a bag by heat-sealing.

In the method for producing a heat-resistant packaging bag of the present invention, the functional resin layer is a barrier resin layer composed of a polyester resin layer having a barrier layer composed of a vapor deposition layer or a coating layer, and the vapor deposition layer or the coating layer is used. It is preferable to form a barrier layer by forming it on the laminated film.

In the heat-resistant packaging bag of the present invention, the amount of adhesive used is reduced by using a multilayer film in which the functional resin layer required for the packaging bag is efficiently laminated, and productivity, economy and flavor are achieved. Is excellent.
Further, according to the method for producing a packaging bag of the present invention, the functional resin layer can be efficiently laminated by coextrusion, which is excellent in productivity and economy.

It is a figure which shows an example of the layer structure of the multilayer film used for the packaging bag of this invention. It is a figure which shows another example of the layer structure of the multilayer film used for the packaging bag of this invention. It is a figure which shows another example of the layer structure of the multilayer film used for the packaging bag of this invention. It is a figure which shows another example of the layer structure of the multilayer film used for the packaging bag of this invention. It is a figure which shows another example of the layer structure of the multilayer film used for the packaging bag of this invention.

(Heat-resistant packaging bag)
The heat-resistant packaging bag of the present invention is made of a multilayer film having at least a base material layer made of a polyester resin and a functional resin layer based on a polyester resin adjacent to the base material layer, and the base material layer and the functionality. An important feature is that the resin layer is a laminated film produced by coextrusion.
That is, since the base resin of the base material layer and the functional resin layer is made of polyester resin, the packaging bag of the present invention has heat resistance that can be used for retort sterilization and the like. Further, since the base resin of the base material layer and the functional resin layer are both made of polyester resin, they can be laminated without using an adhesive, so that they can be produced as one laminated film by coextrusion. is there. Therefore, in the present invention, it is possible to reduce the number of times of laminating the multilayer film constituting the package.
The number of times of laminating in the present specification means the number of times of laminating by a film laminating method in which films are bonded to each other using an adhesive such as dry laminating, and excludes coextruded laminating or extruded laminating in which films are formed and laminated at the same time. Is what you do.

[Base material layer]
As the polyester resin constituting the base material layer, the polyester resin conventionally used for the heat-resistant packaging bag can be used without limitation, but in particular, the polyester resin mainly composed of ethylene terephthalate unit and / or butylene terephthalate is mainly used. The polyester to be used can be preferably used.
A polyester mainly composed of an ethylene terephthalate unit is a polyester in which 50 mol% or more of a carboxylic acid component is composed of a terephthalic acid component and 50% or more of an alcohol component is an ethylene glycol component, and a polyester mainly composed of a butylene terephthalate unit. The resin is a polyester in which 50 mol% or more of the dicarboxylic acid component is composed of terephthalic acid and 50 mol% or more of the alcohol component is 1,4-butanediol, and these polyesters may be homopolyesters or copolymerized polyesters. Alternatively, it may be a blend of two or more of these.

Examples of the carboxylic acid component other than the terephthalic acid component include isophthalic acid, naphthalenedicarboxylic acid, p-β-oxyethoxybenzoic acid, biphenyl-4,4'-dicarboxylic acid, diphenoxyethane-4,4'-dicarboxylic acid, and 5 -Sodium sulfoisophthalic acid, hexahydroterephthalic acid, adipic acid, sebacic acid, trimellitic acid, pyromellitic acid and the like can be mentioned.
On the other hand, as alcohol components other than ethylene glycol and 1,4-butanediol, propylene glycol, neopentyl glycol, 1,6-hexylene glycol, diethylene glycol, triethylene glycol, cyclohexanedimethanol, bisphenol A ethylene oxide adduct, etc. Alcohol components such as glycerol, trimethylolpropane, pentaerythritol, dipentaerythritol, and sorbitan can be mentioned.
In addition to the above, polyethylene naphthalate, polybutylene naphthalate and the like can also be preferably used as the polyester resin constituting the base material layer.

As the polyester resin that can be used for the base material layer, recycled polyester or biomass polyester can also be used in addition to the above polyester resin.
Recycled polyester is polyester recycled by mechanical recycling, and is generally recycled by crushing and cleaning the recovered polyester bottle. This polyester contains ethylene glycol and carboxylic acid as alcohol components. It contains terephthalic acid and isophthalic acid as components.
The recycled polyester may contain virgin polyester together with the recycled polyester.

Biomass polyester is a polyester generally made of biomass ethanol-derived ethylene glycol produced from sugar cane, corn, or the like as a diol component, and the above-mentioned fossil fuel-derived dicarboxylic acid as a dicarboxylic acid component.
The biomass polyester may contain virgin polyester together with the biomass polyester.

Conventionally known compounding agents for resins such as lubricants, antiblocking agents, fillers, antioxidants, coloring agents, and antistatic agents can be blended in the base material layer with a known formulation.
The polyester resin should have a molecular weight capable of forming a film, and the intrinsic viscosity measured using a phenol / tetrachloroethane mixed solvent as a solvent is 0.5 dL / g or more, particularly in the range of 0.6 to 1.5 dL / g. It is preferable from the viewpoint of mechanical strength.
The thickness of the base material layer is preferably in the range of 5 to 50 μm, particularly 10 to 30 μm, from the viewpoint of the mechanical strength of the packaging bag and the like. If the thickness of the base material layer is thinner than the above range, the mechanical strength and crack resistance are inferior to those in the above range, while if it is thicker than the above range, the tear is torn as compared to the case in the above range. It becomes inferior in sex and economy.

[Functional resin layer]
The functional resin provided in the packaging bag of the present invention is based on a polyester resin that can be laminated by coextrusion with the base material layer, and is not limited to the barrier resin layer, the thermosetting resin layer, and the like. Examples thereof include an oxygen-absorbing resin layer, an easily-openable resin layer, an impact-resistant resin layer, a chemical-resistant layer, a puncture-resistant layer, and a heat-resistant layer. In the present invention, a barrier resin layer and a heat-sealing property are particularly exemplified. It is preferably at least one layer of a resin layer, an oxygen-absorbing resin layer, an easily-openable resin layer, and an impact-resistant resin layer.
As the base resin of the functional resin layer, the polyester resin exemplified as the polyester resin that can be used for the base material layer can be used, and recycled polyester and biomass polyester can also be used.
The polyester resin that is the base of the functional resin layer should also have a molecular weight capable of forming a film like the polyester resin of the base material layer, and preferably has an intrinsic viscosity in the above range.

<Barrier resin layer>
As the barrier resin layer, the polyester resin exemplified for the above-mentioned base material layer is used as a base film, and this polyester resin is coextruded with the polyester resin constituting the base material layer to form a laminated film, which is formed on the laminated film (base). The following barrier layer is formed on the inside or outside of the material layer. Further, as the barrier resin layer, a base film layer, an impact resistant resin layer for improving strength described later, or the like can be used as a base film.
As the barrier layer, a metal oxide vapor deposition layer such as aluminum oxide, an inorganic oxide vapor deposition layer represented by a silicon oxide vapor deposition layer, or an inorganic vapor deposition layer represented by a hydrocarbon-based vapor deposition layer such as diamond-like carbon is used. An inorganic vapor deposition film having a coating agent, a coating agent made of a compound having a metalloxane bond with a hydrolyzed compound such as a metal alkoxide or a metal halogen compound, or a coating agent made of a gas barrier resin such as a polyvinyl alcohol-based polymer or a polycarboxylic acid-based polymer. The coated coating barrier layer can be exemplified.
The thickness of the base film for forming the barrier layer is preferably in the range of 5 to 50 μm, particularly 10 to 30 μm. If the thickness of the base film is thinner than the above range, the mechanical strength and crack resistance are inferior to those in the above range, while if it is thicker than the above range, the tearability is lower than that in the above range. And it becomes inferior in economy.

<Heat-sealable polyester resin layer>
As the resin constituting the heat-sealable polyester resin layer that can be co-extruded with the base material layer, a known heat-sealable polyester resin can be used. For example, an amorphous polyester such as PETG, a low melting point polyester resin such as an ethylene terephthalate / isophthalate copolymer, or a polyester resin having a high glass transition temperature (Tg) and a low glass transition temperature (Tg) are blended. A polyester resin made of a polyester resin or a polyester-based thermoplastic elastomer such as polytetramethylene glycol-modified polybutylene terephthalate (PBT-PTMG) can be used.
The thickness of the heat seal layer is preferably in the range of 15 to 150 μm, particularly 40 to 80 μm. If the thickness of the heat seal layer is thinner than the above range, the drop strength and heat sealability will be inferior to those in the above range, while if it is thicker than the above range, it will be inferior to the above range. It becomes inferior in tearability and economy.

<Oxygen absorbing resin layer>
As the resin composition constituting the oxygen-absorbing resin layer that can be co-extruded with the base material layer, a known oxygen-absorbing resin composition containing the above-mentioned polyester resin as a matrix resin, an oxidizing organic component, and a transition metal catalyst. Can be used.
The thickness of the oxygen absorbing resin layer is preferably in the range of 5 to 50 μm, particularly 10 to 20 μm. If the thickness of the oxygen-absorbing resin layer is thinner than the above range, the mechanical strength and crack resistance are inferior to those in the above range, while if it is thicker than the above range, it is inferior to the above range. It becomes inferior in tearability and economy.

<Easy-opening resin layer>
The polyester-based resin composition constituting the easily-openable resin layer that can be co-extruded with the base material layer comprises a blend of polybutylene terephthalate and polyethylene terephthalate containing a polytetramethylene glycol unit, and polyethylene terephthalate and a polyester elastomer. , A polyester-based resin composition having linear tearability, such as a blend in which a polyester elastomer is dispersed in polyethylene terephthalate, can be preferably used.
The thickness of the easy-to-open resin layer is preferably in the range of 5 to 50 μm, particularly 10 to 20 μm. If the thickness of the easy-to-open resin layer is thinner than the above range, the mechanical strength and crack resistance are inferior to those in the above range, while if it is thicker than the above range, it is inferior to the case in the above range. It becomes inferior in tearability and economy.

<Impact resistant resin layer>
The impact-resistant resin layer that can be co-extruded with the base material layer improves puncture resistance, drop impact resistance, and the like. Examples of the polyester resin capable of exhibiting such a function include polyesters mainly composed of butylene terephthalate units, and in particular, homopolybutylene terephthalate can be preferably used. Nylon is generally used as the impact-resistant resin layer, but by using a polyester-based resin, it is possible to impart a moisture barrier property that can be used for retort sterilization, water bathing, and the like.
The thickness of the impact-resistant resin layer is preferably in the range of 5 to 50 μm, particularly 10 to 20 μm. If the thickness of the impact-resistant resin layer is thinner than the above range, the piercing strength and drop strength are inferior. On the other hand, if the thickness is thicker than the above range, the film is too hard to handle at the time of bag making and filling of contents. It becomes inferior in economic efficiency.

[Print layer]
The packaging bag of the present invention has a printed layer on the outside and / or inside of the base material layer, but in the present invention, it is particularly preferable that the printed layer is formed on the outside of the base material layer. .. That is, when the print layer is formed on the outside of the base material layer, it is possible to effectively prevent the flavor of the contents from being lowered due to the influence of the printing ink, and the print layer and the top coat layer are formed at the same time after the laminated film is formed. Since this can be done, it is possible to prevent scratches on the print layer. When the printing layer is formed inside the base material layer, it is preferable to form the barrier layer inside the printing layer from the viewpoint of the flavor property of the contents.

As the base material (printing base material) to be printed to form the printing layer, a resin layer such as the above-mentioned base material layer or functional resin layer is used. The resin layer used as the printing base material is subjected to surface treatment such as corona treatment, plasma treatment, flame treatment, etc. to improve the known adhesiveness, and the adhesiveness of polyurethane resin, modified polyester resin, etc. is improved. Therefore, it is also possible to provide an anchor coat layer. Further, a compounding agent for a film, for example, an antiblocking agent such as amorphous silica, various antistatic agents, a lubricant, an antioxidant, an ultraviolet absorber, and the like are blended in a resin layer to be a printing base material according to a known formulation. be able to.

The printing layer uses conventionally known printing inks such as ultraviolet curable type, electron beam curable type, and solvent type, and conventional gravure printing method, inkjet printing, electrophotographic printing, flexo printing method, offset printing method, screen printing method, and the like. A known printing method can be appropriately selected. In particular, when it is desired to print beautiful characters and patterns with rich color tones using a large number of colors, it is preferable to form a print layer by gravure printing.
As the printing layer, a plurality of printing inks of a single color or a plurality of colors (for example, 2 to 10 colors) are used on one side of the resin layer serving as the printing base material, using a printing roller and a printing means such as gravure. In the case of color, it can be formed by repeating printing in sequence.
Further, the printing layer may have a two-layer structure consisting of a solid printing layer and a pattern layer.
As the printing ink, it is preferable to use an ink using a heat-curable urethane resin or the like as a binder, but the printing ink is not limited to this, and is not limited to this, but is limited to acrylic resin, polyester resin, salt vinegar resin, and polyamide resin. Ink using a resin, an epoxy resin, a nitrocellulose resin, a chlorinated polypropylene resin or the like as a binder can also be used. Further, as a binder, an ink used by blending a plurality of the above resins can also be used. Further, a polyisocyanate resin, an amino resin, or the like can be added as an ink curing agent.

[Top coat layer]
When the print layer is formed on the outer surface side, it is preferable to form a top coat layer for protecting the print layer.
As the top coat layer, a coating composed of a conventionally known coating composition such as a thermosetting coating material, an ultraviolet curing type coating material, and an electron beam curing type coating material using an unsaturated polyester resin, an epoxy resin, a curable acrylic resin or the like. A film or a resin layer made of a single or blended nitrocellulose resin, acrylic resin, polycarbonate resin and the like can be used. Further, a polyisocyanate resin, an amino resin, or the like can be added as a curing agent for the thermosetting paint.
When the top coat layer is formed of a thermosetting paint, it is desirable to bake it at a temperature equal to or lower than the melting point of the base resin.

[Heat seal layer]
In the present invention, in addition to the above-mentioned heat-sealing resin layer made of a polyester resin that can be coextruded with the base material layer as the functional resin layer, a heat-sealing layer by film lamination or the like can be formed. That is, when the functional resin layer constituting the laminated film by coextrusion with the base material layer is a functional resin layer other than the heat-sealing layer, the heat-sealing layer is further formed on the laminated film.
As the heat-sealing layer further formed on such a laminated film, a heat-sealing layer made of polyolefin or the like conventionally used for the heat-sealing layer can be used, but from the viewpoint of heat resistance, it is preferably made of polypropylene. ..

[Adhesive layer]
As described above, in the present invention, when the base material layer and the functional resin layer are coextruded to form a laminated film and another resin layer is further laminated on the laminated film, film lamination or extrusion is performed as described later. It can be laminated by laminating, and a known adhesive depending on the laminating method can be used.
For example, in dry lamination, polyurethane-based, polyacrylic-based, polyester-based, epoxy-based, and polyvinyl acetate-based adhesives can be used, and in hot melt lamination, ethylene-vinyl acetate copolymer (EVA) and the like can be used. Hot melt adhesives can be used.
In the present invention, it is particularly desirable to use a solvent-free urethane-based adhesive in order to reduce the influence of the solvent in the adhesive on the flavor of the contents.

(Layer structure)
The multilayer film used for the packaging bag of the present invention will be described with reference to the accompanying drawings.
In the multilayer film shown in FIG. 1, a functional resin layer 2 is formed on one surface of the base material layer 1, and a printing layer 3 is formed on the side of the base material layer 1 opposite to the functional resin layer 2. There is. A top coat layer 4 for protecting the print layer is formed on the print layer 3.
In this embodiment, the base material layer 1 and the functional resin layer 2 are formed as a laminated film 10 by coextrusion, and printing is applied to the base material layer side of the laminated film 10 and a top coat layer is formed. There is. In this embodiment, the number of laminations is zero.
In this aspect, when the functional resin layer is a heat-sealing layer, the packaging bag can be manufactured by superimposing the multilayer films shown in FIG. 1 so that the heat-sealing layers face each other and heat-sealing.
When the functional resin layer is other than the heat-sealing layer, a film made of a heat-sealing resin such as polypropylene is laminated on the functional resin layer side with a film laminate or a molten resin extruded and laminated via an adhesive. As a result, a multilayer film is formed.

The multilayer film shown in FIG. 2 is a multilayer film in which a barrier resin layer 5 having a barrier layer 5b formed on a base film 5a made of a polyester resin is formed as a functional resin layer. The base film 5a of the base film layer 1 and the barrier resin layer 5 is formed as a laminated film 10 by coextrusion, and the barrier layer 5b is formed on the base film 5a side of the laminated film 10.
In this embodiment, the printing layer 3 and the top coat layer 4 are formed on the base material layer 1 side as in FIG. 1, and the heat seal layer 7 is laminated on the barrier layer 5b side via the adhesive layer 8. The result is a multilayer film used for packaging bags. In this embodiment, the number of times of laminating is one.

In the multilayer film shown in FIG. 3, a vapor deposition layer 5b and a vapor deposition layer are formed on the side of the substrate layer 1 of the laminated film 10 in which a heat seal layer 2 made of polyester resin as a functional resin layer is coextruded with the substrate layer 1. It is a multilayer film in which a printing layer 3 and a top coat layer are formed on 5b. In this embodiment, the number of laminations is zero.

In the multilayer film shown in FIG. 4,

functional resin layers

2a and 2b are formed as laminated films by coextrusion on both surfaces of the base material layer 1, and a heat seal layer 2a made of polyester resin is formed as the functional resin layer 2a. Then, an impact-resistant resin layer, an easily-openable resin layer, or the like can be formed as the functional resin layer 2b on the other side. A printing layer 3 and a top coat layer 4 are formed on the functional resin layer 2b. In this embodiment, the number of laminations is zero.

In the multilayer film shown in FIG. 5, a base material layer 1 and a functional resin layer 2 such as an impact resistant resin layer or an easily openable resin layer are formed as a laminated film by coextrusion, and a printing layer is formed on the functional resin layer 2. 3 and the top coat layer 4 are formed, and a heat seal layer 7 made of a heat sealable resin such as a polypropylene film is laminated on the base material layer 1 via an adhesive layer 8. In this embodiment, the number of times of laminating is one. Further, in the figure, the base material layer 1 is located inside, but of course, the functional resin layer 2 and the base material layer 1 can be reversed.

The multilayer film constituting the packaging bag of the present invention is not limited to the above-mentioned layer structure, and can take various aspects. For example, when the printing layer is formed inside, the base material layer and the functional resin layer are co-extruded to form a laminated film, the printing layer is formed on the inner surface side of the laminated film, and the barrier layer is formed on the printing layer. By forming and laminating this with a heat seal layer, it is possible to prevent the flavor property from being impaired (coextrusion laminated film of base material layer / functional resin layer / printing layer / barrier layer / adhesive layer / heat seal). layer).
Further, at least one type of functional resin layer may be provided depending on the intended use of the packaging bag, and all functional resin layers may be provided.

(Manufacturing method of multilayer film)
In the present invention, when producing a multilayer film used for manufacturing a packaging bag, a laminated film in which a base material layer made of polyester resin and at least one functional resin layer based on polyester resin are laminated by coextrusion is used. Manufactured in advance.
The production of the laminated film by coextrusion can be performed by a conventionally known method. Using an extruder corresponding to each type of resin layer, melts of each resin are superposed in a multilayer multiplex die, and this is die orifice. It is done by extruding from. This film material is preliminarily formed as a laminated film by a T-die method, an inflation film forming method, or the like.
The laminated film can be either an unstretched film or a stretched film, but a stretched film is desirable from the viewpoint of mechanical strength and the like.

When the formed laminated film does not have a heat-sealing layer as a functional resin layer, the film is laminated with an adhesive to the film made of a heat-resistant heat-sealing resin such as polypropylene described above. ..
The heat seal layer can be bonded to the laminated film by conventionally known methods such as dry lamination, non-solvent dry lamination, and hot melt lamination.

Further, as shown in FIG. 4, when a heat-sealing resin layer made of polyester resin is formed as the functional resin layer, the heat-sealing layer made of polyester resin, the base material layer made of polyester resin, and the polyester resin A three-layer laminated film composed of a functional resin layer based on the above is formed by coextrusion lamination, and a print layer is formed on the functional resin layer side of the laminated film as described later, and then the print layer is formed. By forming the top coat layer on the top coat layer, the multilayer film can be formed with zero number of laminating without using an adhesive.

When forming a barrier layer composed of a vapor deposition layer or a coating layer, in the embodiment shown in FIG. 2, the base layer 5a made of a polyester resin as a base for forming the barrier layer 5b and the base material layer 1 are coextruded. By producing a laminated film and forming the above-mentioned vapor-deposited layer or coating layer 5b on the polyester resin layer 5a, a multilayer film having a barrier resin layer can be formed. Further, in the embodiment shown in FIG. 3, the barrier layer 5b is formed by forming the barrier layer 5b using the base material layer 1 of the laminated film 10 in which the heat-sealing polyester resin layer 2 and the base material layer 1 are co-extruded as the base layer. A multilayer film with the above can be formed.

(Manufacturing method of packaging bag)
The packaging bag of the present invention is made by superimposing and heat-sealing the above-mentioned multilayer films so that the heat-sealing layers are on the inner surface.
The shape of the packaging bag is not limited as long as it is made of the above-mentioned multilayer film, and various shapes such as a pillow type pouch, a gusset type pouch, and a standing pouch can be adopted.
In the packaging bag of the present invention, when the print layer and the top coat layer are formed on the outside of the multilayer film, it is preferable to form the print layer and the top coat layer in the state of the multilayer film, but the print layer and the top coat are formed. A packaging bag obtained by first creating a packaging bag obtained by stacking and heat-sealing a multilayer film in which necessary layers are laminated except for a layer so that the heat-sealing layers face each other is first prepared, and a printing layer and a printing layer are formed on the outer surface of the packaging bag. A top coat layer may be formed.

(Evaluation method)
1. 1. Productivity and economic efficiency evaluation In the preparation of packaging bags, the smaller the number of times of laminating with an adhesive, the higher the productivity and economic efficiency. Therefore, in the multilayer film of the heat-resistant packaging bag produced by the method described later, the case where the film is produced without laminating using the adhesive even once is ⊚, and the case where the number of times of laminating using the adhesive is once is ○. The case where the number of times of laminating using the adhesive was 2 or more was evaluated as x.

2. 2. Sensory evaluation As the sensory evaluation, a 4-point evaluation method by 12 panels and a significant difference test (risk rate 5%) using Reference Example 1 as a reference (control) were performed.
(1) A sample of Reference Example 1 below was prepared as a criterion (control) for a significant difference test (risk rate 5%) of sensory evaluation. Further, as a comparative sample of Reference Example 1, unpacked and unsterilized ultrapure water was also prepared as Reference Example 2 below.
As Reference Example 1, a printing layer was formed on the corona-treated surface of polyethylene terephthalate resin (PET film) by a gravure method. Further, the printed surface of the PET film is laminated with aluminum (AL) foil as a laminated surface, and the AL foil surface is laminated with 50 μm unstretched polypropylene (CPP film) as a laminated surface to form a multilayer film, further heat resistance. A packaging bag was prepared. This heat-resistant packaging bag was filled with 200 g of ultrapure water, sterilized and cooled by the method described later, and used as a reference sample for sensory evaluation.
In the 4-point evaluation of Reference Example 1, the average value was 1.4 and the standard deviation was 0.48. In the 4-point evaluation of Reference Example 2, the average value was 1.3 and the standard deviation was 0.55. When Reference Example 1 and Reference Example 2 are compared, the result is that there is no significant difference at a risk rate of 5%, and the heat-resistant packaging bag of Reference Example 1 has the same result as unwrapped and unsterilized ultrapure water. I understand. Therefore, the ultrapure water filled in the heat-resistant packaging bag of Reference Example 1 was used as a reference sample for sensory evaluation of Examples 1 to 5 and Comparative Example 1 described later.

(2) 200 g of ultrapure water was filled in the heat-resistant packaging bags of Examples 1 to 5 and Comparative Example 1 prepared by the method described later, and steam retort sterilization was performed at 130 ° C. for 30 minutes, and then the temperature was (25 ° C.). It was cooled to and used as a sample for sensory evaluation.
The 4-point evaluation was made by 12 panels, "(1 point) tasteless", "(2 points) slightly tasted", "(3 points) tasted", "(4 points) tasted considerably". The average value and standard deviation of each sample of Examples 1 to 5 and Comparative Example 1 were obtained.
Similarly, a significant difference test (risk rate 5%) was performed on each sample of Examples 1 to 5 and Comparative Example 1 by a panel of 12 people using Reference Example 1 as a reference (control). Those with a significant difference at a risk rate of 5% were evaluated as "yes", and those without a significant difference were evaluated as "none".

(How to make a heat-resistant packaging bag)
1. 1. Material Polyethylene terephthalate resin (PET) or polybutylene terephthalate resin (PBT) as the constituent resin of the base material layer, polyethylene terephthalate resin (PET) or polybutylene terephthalate as the barrier resin layer as the base resin of the functional resin layer. Polybutylene terephthalate resin (PBT) is used as the impact-resistant resin layer, polytetramethylene glycol-modified polybutylene terephthalate resin (PBT-PTMG) is used as the heat-sealable resin layer, and the resin (PBT) is used for various moldings. did. Each resin was dried before molding. When the heat seal layer was not formed as the functional resin layer, a non-stretched polypropylene (CPP) film having a thickness of 50 μm was used as the heat seal layer constituent film.

2. 2. Molding (1) Molding of cast film A multi-layer coextruded cast film was formed using a lab plast mill (manufactured by Toyo Seiki Seisakusho Co., Ltd.) equipped with a 3-layer multilayer T-die. The resins extruded from the first, second, and third extruders were merged with a T-die to form a three-kind three-layer film laminated in the order of 1st, 2nd, and 3rd. The temperature settings of all T-dies were set to 280 ° C., and the temperature settings of the extruder were changed depending on the supplied resin.

(2) Molding of stretched film Using the cast film as the original fabric before stretching, biaxial stretching and molding was performed with a biaxial stretching test device (x6HS: Toyo Seiki Seisakusho Co., Ltd.), and the vertical axis was 3.5 times and the horizontal axis. A stretched film was formed at a stretching ratio of 3.5 times.

(3) Formation of Barrier Layer An inorganic oxide vapor deposition film was formed on one side of the base film by a vacuum vapor deposition method using alumina as an evaporation source to form a barrier layer.

(4) Formation of Print Layer A print layer was formed on the vapor-deposited surface or the non-deposited surface of the base film on which the barrier layer was formed by a gravure method. When the printing layer is the outermost layer, a coating composition using epoxy as a base resin is used, and an amount of ² mg / m ² is applied by a gravure method and baked at 130 ° C. to form a top coat layer. ..

(5) Molding of Laminated Body / Laminated Bag A CPP film as a heat-sealing layer is dry-laminated using a urethane-based adhesive (3 μm) on a stretched film that does not form a heat-sealing layer as a functional resin layer. A multilayer film was molded. Next, this multilayer film was made into a bag with a three-way seal to prepare a heat-resistant packaging bag having a width of 130 mm and a length of 175 mm.

(Example 1)
According to the casting film molding method, PET is supplied to the first and third extruders (set temperature 280 ° C.) and PBT is supplied to the second extruder (set temperature 250 ° C.), and PET / PBT / is formed as a layer structure. A cast film to be PET was molded. The total layer thickness of this film was 200 μm, and the ratio of each layer thickness was PET / PBT / PET = 0.5 / 1 / 0.5.
Using this cast film as the original fabric before stretching, the stretched film was molded according to the method for molding the stretched film. This film had a total layer thickness of 19 μm.
Then, by the method described above, a barrier layer made of an alumina vapor deposition film is formed on one side of the stretched film, and a print layer is formed on the barrier layer by a gravure method, and then the print layer forming surface is used as a laminate surface to form a urethane adhesive. Using (3 μm), a multilayer film was formed by dry laminating with a CPP film as a heat seal layer. The layer structure is shown in Table 1.
A heat-resistant packaging bag was produced by superimposing the CPP film surfaces of the obtained multilayer film on each other and heat-sealing them.
The results of productivity and economic evaluation and sensory evaluation are shown in Table 1.

(Example 2)
According to the casting film molding method, PBT is supplied to the first and third extruders (set temperature 250 ° C.) and PET is supplied to the second extruder (set temperature 280 ° C.), and PBT / PET / is formed as a layer structure. A cast film to be PBT was molded. The total layer thickness of this film was 170 μm, and the ratio of each layer thickness was PET / PBT / PET = 0.3 / 1 / 0.4.
Using this cast film as the original fabric before stretching, the stretched film was molded according to the method for molding the stretched film. This film had a total layer thickness of 17 μm.
Next, a barrier layer, a printing layer, and a CPP film were laminated on this stretched film in the same manner as in Example 1 to form a multilayer film, and a heat-resistant packaging bag was further produced.
Table 1 shows the results of the layer composition, productivity and economic efficiency evaluation, and sensory evaluation of the multilayer film.

(Example 3)
According to the casting film molding method, PET is used in the first extruder (set temperature 280 ° C.), PBT is used in the second extruder (set temperature 250 ° C.), and PBT is used in the third extruder (set temperature 250 ° C.). A dry blend of PBT-PTMG / PBT = 8/2 (weight ratio) was supplied, and a cast film having a layer structure of PET / PBT / PBT-PTMG was formed. The total layer thickness of this film was 200 μm, and the ratio of each layer thickness was PET / PBT / PBT-PTMG = 1/1/1.
Using this cast film as the original fabric before stretching, the stretched film was molded according to the method for molding the stretched film. This film had a total layer thickness of 17 μm.
Next, a barrier layer made of an alumina-deposited film was formed on the PET surface of this stretched film, and a printing layer was formed on the barrier layer to form a multilayer film, and a heat-resistant packaging bag was further produced.
Table 1 shows the results of the layer composition, productivity and economic efficiency evaluation, and sensory evaluation of the multilayer film.

(Example 4)
According to the casting film molding method, PET is supplied to the first and third extruders (set temperature 280 ° C.) and PBT is supplied to the second extruder (set temperature 250 ° C.), and PET / PBT / is formed as a layer structure. A cast film to be PET was molded. The total layer thickness of this film was 200 μm, and the ratio of each layer thickness was PET / PBT / PET = 0.5 / 1 / 0.5.
Using this cast film as the original fabric before stretching, the stretched film was molded according to the method for molding the stretched film. This film had a total layer thickness of 19 μm.
Next, a barrier layer made of an alumina vapor deposition film was formed on one side of the stretched film, and a top coat layer was formed on the printed layer and the printed layer by a gravure method on the surface without the barrier layer. Further, in the same manner as in Example 1, the barrier layer side of the stretched film was used as a laminating surface, and the film was laminated with a CPP film to form a multilayer film, and a heat-resistant packaging bag was further produced.
Table 1 shows the results of the layer composition, productivity and economic efficiency evaluation, and sensory evaluation of the multilayer film.

(Example 5)
According to the casting film molding method, PBT is supplied to the first and third extruders (set temperature 250 ° C.) and PET is supplied to the second extruder (set temperature 280 ° C.), and PBT / PET / is formed as a layer structure. A cast film to be PBT was molded. The total layer thickness of this film was 170 μm, and the ratio of each layer thickness was PBT / PET / PBT = 0.3 / 1 / 0.4.
Using this cast film as the original fabric before stretching, the stretched film was molded according to the method for molding the stretched film. This film had a total layer thickness of 17 μm.
Next, a barrier layer made of an alumina vapor deposition film was formed on one side of the stretched film, and a top coat layer was formed on the printed layer and the printed layer by a gravure method on the surface without the barrier layer. Further, in the same manner as in Example 1, the barrier layer side of the stretched film was used as a laminating surface, and the film was laminated with a CPP film to form a multilayer film, and a heat-resistant packaging bag was further produced.
Table 1 shows the results of the layer composition, productivity and economic efficiency evaluation, and sensory evaluation of the multilayer film.

(Comparative Example 1)
A barrier layer made of an alumina-deposited film was formed on one side of the PET film, and a printing layer was formed on the barrier layer by a gravure method. Further, according to the above description, the print layer forming surface of the PET film is laminated with a nylon (NY) film as a laminating surface, and the NY film surface is laminated with a CPP film as a laminating surface to form a three-layer multilayer film. A heat-resistant packaging bag was produced.
Table 1 shows the results of the layer composition, productivity and economic efficiency evaluation, and sensory evaluation of the multilayer film.

The packaging bag of the present invention has the performance required for a packaging bag such as heat resistance and barrier properties, and is made of a multilayer film in which the number of times of lamination is small and the amount of adhesive used is reduced, so that productivity and economy are economical. It has excellent flavor and can be suitably used for food applications.

1 base material layer, 2 functional resin layer, 3 printing layer, 4 top coat layer, 5 barrier resin layer, 7 heat seal layer, 8 adhesive layer.

Claims

A laminated film composed of a base material layer made of polyester resin and a multilayer film having at least a functional resin layer based on polyester resin adjacent to the base material layer, and the base material layer and the functional resin layer are coextruded. A heat-resistant packaging bag characterized by being present.
The heat-resistant packaging bag according to claim 1, wherein the multilayer film has a printing layer.
The heat resistance according to claim 1 or 2, wherein the functional resin layer is at least one layer of a barrier resin layer, a heat-sealing resin layer, an oxygen-absorbing resin layer, an easily-openable resin layer, and an impact-resistant resin layer. Packaging bag.
The heat-resistant packaging bag according to any one of claims 1 to 3, wherein the functional resin layer is a heat-sealing resin layer, and a barrier layer composed of a vapor-deposited layer or a coating layer is formed on the base material layer.
3. The functional resin layer is a barrier resin layer made of a polyester resin layer having a barrier layer made of a vapor deposition layer or a coating layer, and the base material layer and the polyester resin layer are laminated films by coextrusion. Described heat resistant packaging bag.
The heat-sealable resin layer is formed on one surface of the base material layer, and any one of the oxygen-absorbing resin layer, the easily-openable resin layer, and the impact-resistant resin layer is formed on the other surface. The three layers of the heat-sealing resin layer, the base material layer, the oxygen-absorbing resin layer, the easily-openable resin layer, and the impact-resistant resin layer are coextruded. The heat-resistant packaging bag according to claim 3, which is a laminated film.
The functional resin layer is any one of the barrier resin layer, the oxygen absorbing resin layer, the easily openable resin layer, and the impact resistant resin layer, and the functional resin of the base material layer. The heat-resistant packaging bag according to claim 3, wherein a thermosetting layer made of polyolefin is formed via an adhesive on the surface opposite to the surface adjacent to the layers.
The heat-resistant packaging bag according to any one of claims 2 to 7, wherein the printing layer is formed on the outer surface side of the base material layer, and the top coat layer is formed on the outer surface side of the printing layer.
A laminated film composed of a base material layer made of polyester resin and a functional resin layer based on polyester resin is formed by coextrusion lamination, and heat made of polyolefin is provided on the base material layer side of the laminated film via an adhesive. A multilayer film formed by forming a sealing layer, forming a printing layer on the functional resin layer side of the laminated film, and then forming a top coat layer on the printing layer is formed by heat-sealing layers made of the polyolefin. A method for producing a heat-resistant packaging bag, which comprises making a bag by superimposing and heat-sealing the film so that the surface is on the inner surface.
A laminated film composed of a heat-sealable resin layer made of polyester resin, a base material layer made of polyester resin, and a functional resin layer based on polyester resin is formed by coextrusion lamination, and the functional resin layer of the laminated film is formed. After forming a printing layer on the side, a multilayer film formed by forming a top coat layer on the printing layer is overlapped so that the heat-sealing resin layers are on the inner surface, and heat-sealed. A method for manufacturing a heat-resistant packaging bag.
The functional resin layer is a barrier resin layer composed of a polyester resin layer having a barrier layer composed of a vapor deposition layer or a coating layer, and the barrier layer is formed by forming the vapor deposition layer or the coating layer on the laminated film. The method for producing a heat-resistant packaging bag according to claim 9 or 10.