JP2019014043A - Laminate and packaging bag using the same - Google Patents

Abstract

To provide a laminate for liquid small bag package which has good piercing strength and gas barrier property, has good filling suitability of a liquid seasoning and the like, and prevents lowering of the gas barrier property before treatment even when subjected to treatments such as boiling sterilization or heating/pressurizing sterilization.SOLUTION: A heat-sealable laminate 40 has a transparent gas barrier film 10 and a heat adhesive resin layer 21, where the transparent gas barrier film has at least a base material film 1 containing a polyester resin containing a butylene terephthalate unit as a main constitutional unit, an inorganic oxide layer 2 and a gas barrier coating layer 3 in this order, the heat adhesive resin layer is a heat adhesive resin layer which is laminated on the gas barrier coating layer and has a thickness of 20-60 μm, and a thermal shrinkage after heated at 150°C for 30 minutes represented by the expression (1) is 1.0 or more and less than 3.0%. Expression (1): (length before heating-length after heating)/length before heating×100(%).SELECTED DRAWING: Figure 1

Description

  The present invention relates to a heat-sealable laminate and a packaging bag for a liquid sachet package using the laminate.

  Conventionally, liquid-packaging sachets for filling and packaging seasonings made of liquid or viscous materials, etc., have been developed and proposed in various forms, but the most common of them. A polyethylene terephthalate film or nylon film as a base film, a resin film coated with an aluminum foil or a polyvinylidene chloride resin composition as a barrier material, and polyethylene as a heat-adhesive resin layer There is known a sachet formed by making a wrapping laminated film obtained by sequentially laminating a series of resin layers.

  These are, when filled and packaged with liquid seasonings such as soy sauce, sauce, etc., excellent in oxygen gas barrier properties, water vapor barrier properties, etc., and excellent in flavor retention, chemical resistance, and other properties, Even when stored and stored for a long period of time, the liquid sachet has excellent characteristics without impairing the flavor and taste of the contents.

  However, in the liquid-filled packaging sachets as described above, due to the recent increase in awareness of environmental problems, for example, when discarded as waste after use and incinerated, Problems such as generation of harmful gases are pointed out, and in packaging materials including aluminum foil, problems such as damage to the incinerator are pointed out. It was inevitable that there would be concerns about the impact on

  In order to solve the above problems, in a liquid-filled packaging sachet, for example, as a material having a barrier property, a polyamide resin or a resin made of a saponified ethylene-vinyl acetate copolymer or the like is used. Packaging bags made of laminated materials using these films have been proposed, but these cases also have the above-mentioned problems due to lack of barrier properties or high humidity dependency. The reality is that it has not yet been resolved.

  Furthermore, in recent years, in liquid-filled packaging sachets, as a material having a barrier property, for example, a silicon oxide, an oxide is formed on one surface of a base film made of a resin film such as a polyester resin or a polyamide resin. It has been proposed to use a barrier film in which a deposited film of an inorganic oxide such as aluminum is provided by vacuum deposition (for example, Patent Documents 1 and 2).

However, in the gas barrier film of Patent Document 1, since the polyethylene terephthalate film is used as a base material, the puncture strength is not sufficient and there is a problem in pinhole resistance.
In addition, since the gas barrier film of Patent Document 2 uses a nylon film as a base material, in contrast to the polyethylene terephthalate film, it exhibits sufficient physical properties for puncture strength, but particularly for the water vapor barrier property, the polyethylene terephthalate film. Inferior. Furthermore, the nylon film has a problem that the suitability for filling a liquid seasoning or the like is inferior due to the difference in slipping property compared to polyethylene terephthalate.

JP 2005-88431 A JP 2009-262992 A JP 2002-179892 A

  The present invention has been made in view of the above-mentioned problems, has good puncture strength and gas barrier properties, and has good filling suitability such as liquid seasonings, such as boiling sterilization and heating / pressure sterilization. It is an object of the present invention to provide a laminated body for a packaging bag for a liquid sachet packaging body and a packaging bag produced using the laminated body, which does not deteriorate the gas barrier property that it had before the treatment even if the treatment is performed. .

As means for solving the above problems, the invention according to claim 1 of the present invention is a heat-sealable laminate,
A transparent gas barrier film and a heat-adhesive resin layer;
The transparent gas barrier film comprises at least a base film containing a polyester resin mainly composed of a butylene terephthalate unit, one or more inorganic oxide layers, and a gas barrier coating layer in this order.
The thermal adhesive resin layer is a thermal adhesive resin layer having a thickness of 20 μm or more and 60 μm or less laminated on the gas barrier coating layer.
In at least one direction, the laminate is characterized in that the thermal shrinkage represented by the following formula (1) after heating at 150 ° C. for 30 minutes is 1.0 or more and less than 3.0%.
(Length before heating−length after heating) / length before heating × 100 (%) (1)

  The invention according to claim 2 is the laminate according to claim 1, wherein at least one of Al and Si is contained in at least one of the inorganic oxide layers.

  The invention according to claim 3 is the laminate according to claim 1 or 2, wherein the gas barrier coating layer is a layer containing a water-soluble polymer and an inorganic oxide.

  The invention according to claim 4 is the laminate according to any one of claims 1 to 3, wherein an anchor coat layer is provided between the gas barrier coating layer and the thermal adhesive resin layer. .

  The invention according to claim 5 is characterized in that the heat-adhesive resin layer is a heat-adhesive resin layer having heat sealability, and has excellent gas barrier properties according to any one of claims 1 to 4. Is the body.

  The invention described in claim 6 is a packaging bag comprising the laminate according to any one of claims 1 to 5.

  The laminate for the liquid sachet package of the present invention uses a barrier film comprising a base film, an inorganic oxide vapor-deposited film and a gas barrier film layer as a barrier material, so that oxygen gas, water vapor, etc. It has excellent gas barrier properties that prevent permeation.

  In addition, the packaging bag for the liquid sachet packaging body of the present invention constitutes a laminated material in which a heat-adhesive resin layer is laminated, and further constitutes a packaging bag by making a bag using this, The packaging bag is capable of producing liquid sachet packages having various forms that have filling suitability and excellent pinhole resistance.

It is sectional drawing which illustrates roughly one Embodiment of the laminated body which comprises the liquid pouch packaging body of this invention. It is sectional drawing which illustrates roughly one Embodiment of the liquid sachet package formed by filling and packaging a bag and the contents using the laminated body concerning this invention shown in the said FIG.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
The laminate of the present invention is a laminate that can be heat sealed.
The laminate of the present invention includes a transparent gas barrier film and a heat-adhesive resin layer.

  The transparent gas barrier film includes at least a base film containing a polyester resin mainly composed of a butylene terephthalate unit, one or more inorganic oxide layers, and a gas barrier coating layer in this order.

The heat-adhesive resin layer is a heat-adhesive resin layer having a thickness of 20 μm or more and 60 μm or less laminated on the gas barrier coating layer by an extrusion laminating method, and after heating at 150 ° C. for 30 minutes in at least one direction The thermal contraction rate represented by the following formula (1) is 1.0 or more and less than 3.0%.
(Length before heating−length after heating) / length before heating × 100 (%) (1)

  At least one of Al and Si may be contained in at least one inorganic oxide layer.

  Further, the gas barrier coating layer is formed on the vapor-deposited thin film layer made of an inorganic oxide, and the gas barrier coating layer is an aqueous solution or water containing a water-soluble polymer and one or more metal alkoxides or hydrolyzate products thereof. A layer formed by applying a coating agent mainly composed of an alcohol / alcohol solution and heat-drying may be used.

  An anchor coat layer may be provided between the gas barrier coating layer and the heat adhesive resin layer.

  Moreover, a packaging bag can be produced with the bag making machine conventionally used using the laminated body of this invention.

FIG. 1 is a cross-sectional view schematically illustrating an example of an embodiment of a laminate constituting the liquid pouch package of the present invention.
FIG. 2 schematically illustrates an embodiment of a liquid sachet package obtained by filling and packaging the contents of a bag produced by making a bag using the laminate 40 according to the present invention shown in FIG. It is sectional drawing.

<Liquid sachet packaging>
The liquid sachet package 30 (FIG. 2) of the present invention is a bag made using the laminate 40 illustrated in FIG. 1 and filled with contents.

<Laminate>
The laminate 40 includes a transparent gas barrier film 10 and an anchor coat layer 20 made of an anchor coating agent for laminating on the gas barrier coating layer 3 side of the transparent gas barrier film 10, and a thermal adhesive resin layer on the anchor coat layer 20. 21.

  Below, the structure of the laminated body 40 is demonstrated in detail.

[Transparent gas barrier film]
The transparent gas barrier film 10 includes a base film 1, an inorganic oxide layer 2, and a gas barrier coating layer 3. Note that “film” and “sheet” may be properly used depending on the thickness, but here, the term “film” is used regardless of the thickness.

(Base film)
The base film 1 contains a polyester resin whose main unit is a butylene terephthalate unit. The metal oxide layer 2 becomes a gas barrier layer.
Here, the polyester resin having a butylene terephthalate unit as a main constituent unit means that 60% by mass or more of a repeating unit formed by combining a dicarboxylic acid component and a glycol component of the resin is composed of a butylene terephthalate unit. .

  The polyester resin contained in the base film 1 is preferably polybutylene terephthalate containing 60% by mass or more of polybutylene terephthalate, or a mixed material of polybutylene terephthalate and polyethylene terephthalate. If the polybutylene terephthalate is less than 60% by mass, the impact strength and the pinhole resistance are lowered, and the film properties are not sufficient. The base film 1 may be biaxially stretched or uniaxially stretched, but biaxial stretching is more preferable in order to provide thermal stability.

  Further, by using a polyester resin which is a mixed material of polybutylene terephthalate and polyethylene terephthalate, the puncture strength is also improved. For example, according to Patent Document 3, the PET phase and the PBT phase have independent crystals while being a blend film of a polyester resin mainly containing polyethylene terephthalate (PET) and a polyester resin mainly containing polybutylene terephthalate (PBT). Thus, it is said that a polyester film having high piercing strength can be obtained by having heat resistance and also having flexibility.

  In order to obtain the said independent crystal | crystallization, it is necessary to melt | dissolve separately when producing a polyester film, and it can confirm by detecting a crystal melting peak separately with a differential scanning calorimeter (DSC). it can. A crystal peak of the PBT phase appears on the low temperature side, followed by a crystal peak of the PET phase. By using these two polyester resins, PET and PBT, crystal melting occurs individually while ensuring compatibility to the extent that the glass transition is fused, so that the advantages of the PET phase and PBT phase can be utilized.

  The thickness of the base film 1 is not particularly limited. The thicker the puncture strength, the better, but those having a thickness of about 6 μm to 200 μm can be suitably used depending on the application. The base film 1 may be provided with various pretreatments such as corona treatment, plasma treatment and frame treatment, or an anchor coat layer such as an easy adhesion layer. Separately, a flattening layer may be applied to reduce the unevenness of the base film.

(Coating agent)
Examples of the coating agent for the anchor coat layer and the flattening layer include acrylic resins, epoxy resins, acrylic urethane resins, polyester polyurethane resins, and polyether polyurethane resins. Among these coating agents, acrylic urethane resins and polyester polyurethane resins are preferable from the viewpoint of heat resistance and interlayer adhesion strength.

  As a method of coating the coating agent on the base film 1, a known coating method can be used without any particular limitation, and a dipping method (dipping method), a spray coating method, a method using various coaters, and printing. The method using a machine, the method using a brush, etc. are mentioned. In addition, the types of coaters and printing presses used in these methods and the coating methods thereof include gravure coaters such as direct gravure, reverse gravure, kiss reverse gravure, and offset gravure, reverse roll coater, and micro gravure. A coater, a coater with chamber doctor, an air knife coater, a dip coater, a bar coater, a comma coater, a die coater and the like can be mentioned.

It The coating amount of the coating agent, it is preferable that the mass per 1 m ² after drying by coating the coating agent is 0.01 to 10 g / ^{m 2,} a 0.03~5g / ^{m 2} Is more preferable. If the mass per 1 m ² after coating and drying the coating agent is less than the lower limit, film formation tends to be insufficient. On the other hand, if the upper limit is exceeded, drying is insufficient and the solvent tends to remain. Tend to be.

(Inorganic oxide layer)
The inorganic oxide layer 2 is a gas barrier transparent layer formed on the base film 1 by a vapor deposition method. As a material of the inorganic oxide layer 2, for example, silicon oxide, aluminum oxide, tin oxide, magnesium oxide, or a mixture thereof can be used, but silicon oxide or aluminum oxide is preferable. For the formation of the inorganic oxide layer 2, for example, a vacuum evaporation method, a sputtering method, an ion plating method, or a plasma vapor deposition method can be used. When the vacuum deposition method is used, for example, electron beam heating, resistance heating, or induction heating can be used as a heating means for the evaporation material. When the electron beam heating method is used, the degree of freedom in selecting the evaporation material is great. When the plasma assist method or the ion beam assist method is used at the time of vapor deposition, a denser inorganic oxide layer 2 can be formed. In addition, when reactive vapor deposition in which a gas such as oxygen is blown during vapor deposition, the inorganic oxide layer 2 having excellent transparency can be formed.

  When the thickness of the inorganic oxide layer 2 is small, it is difficult to form the inorganic oxide layer 2 as a uniform continuous film, and sufficient gas barrier properties cannot be obtained. When the thickness is thick, the flexibility is low, and there is a possibility that a crack may occur when the transparent gas barrier film 10 is bent or pulled. Further, the vapor deposition method is not suitable for forming a thick film from an economical viewpoint. The thickness of the inorganic oxide layer 2 is, for example, in the range of 5 nm to 500 nm.

(Gas barrier coating layer)
The gas barrier coating layer 3 is a transparent film formed on the inorganic oxide layer 2 and is made of a mixture containing a transparent resin and an inorganic substance such as an inorganic oxide. Although the gas barrier coating layer 3 can be omitted, when the gas barrier coating layer 3 is provided, the transparent gas barrier film 10 and the liquid pouch packaging 30 having higher gas barrier properties can be obtained. The gas barrier coating layer 3 is made of, for example, a coating solution mainly composed of an aqueous solution or a water / alcohol mixed solution containing a water-soluble polymer and one or more metal alkoxides or hydrolysis products thereof on the inorganic oxide layer 2. It can be obtained by coating and drying.

  As the water-soluble polymer, for example, polyvinyl alcohol (PVA), polyvinyl pyrrolidone, starch, methyl cellulose, carboxymethyl cellulose, sodium alginate, or a mixture thereof can be used. In particular, when PVA is used, the gas barrier coating layer 3 having the most excellent gas barrier properties can be formed. In addition, PVA here is typically obtained by saponifying polyvinyl acetate. As this PVA, various saponified PVA can be used from partially saponified PVA in which several tens% of acetyl groups remain to complete PVA in which only several% of acetyl groups remain. There is no restriction | limiting in the molecular weight of PVA, For example, what has a polymerization degree in the range of 300 to several thousand can be used. In general, high molecular weight PVA having a high degree of saponification and a high degree of polymerization can provide excellent water resistance.

A metal alkoxide is a compound represented by general formula M (OR) _n . Where M is Ti
, Al, Zr, or other metal or Si, and R represents an alkyl group such as a CH ₃ group or a C ₂ H ₅ group. N represents the valence of the element M.
Examples of the metal alkoxide include tetraethoxysilane [Si (OC ₂ H ₅ ) ₄ ] and triisopropoxyaluminum [Al (O-2′-C ₃ H ₇ ) ₃ ], among which tetraethoxysilane, Triisopropoxyaluminum can exist relatively stably in water-containing solutions after hydrolysis.

When alkoxysilane is used as the metal alkoxide, for example, a compound represented by Si (OR ¹ ) ₄ or R ² Si (OR ³ ) ₃ or a mixture thereof can be used as the alkoxysilane. Here, R ¹ and R ³ represent a hydrolyzable group such as a CH ₃ group, a C ₂ H ₅ group, a C ₂ H ₄ OCH ₃ group, and R ² represents an organic functional group.

  In addition, since the metal oxide film obtained by hydrolyzing and condensing a metal alkoxide is hard, cracks are likely to occur due to external force or strain due to volume reduction during condensation. Therefore, it is very difficult to form the metal oxide film with a uniform thickness without causing cracks.

  In contrast, a film formed using a coating solution containing a polymer, a metal alkoxide and / or a hydrolyzate thereof, and water is more flexible than a metal oxide film, and thus cracks are generated. It ’s hard. However, in this film, the metal oxide is not uniformly dispersed microscopically, and a high gas barrier property may not be obtained. When a water-soluble polymer is used as this polymer, a strong hydrogen bond between the hydroxyl group of the polymer and the hydroxyl group of the hydrolyzate of the metal alkoxide is used to convert the metal oxide into the polymer during condensation. Can be uniformly dispersed. Therefore, a gas barrier property close to that of a metal oxide film can be achieved. Therefore, when such a gas barrier coating layer 3 is formed on the inorganic oxide layer 2, a much higher gas barrier property can be achieved as compared with the case where they are used alone.

  Since the gas barrier coating layer 3 obtained by using the coating liquid containing the above-mentioned metal alkoxide and / or its hydrolysis product, a water-soluble polymer having a hydroxyl group, and water forms hydrogen bonds, it is severe. When used in a harsh environment, it may swell due to the ingress of water, eventually resulting in dissolution. Therefore, even if this gas barrier coating layer 3 can achieve high gas barrier properties by laminating the inorganic oxide layer 2 and the gas barrier coating layer 3, the gas barrier coating layer 3 can be used under severe conditions such as a high-temperature and high-humidity environment. Then, there is a possibility that adhesion and gas barrier properties are easily deteriorated.

For example, when an alkoxysilane represented by R ² Si (OR ³ ) ₃ is used as the metal alkoxide, it is difficult to swell even when water enters, and the gas barrier coating layer 3 having excellent water resistance can be obtained. In particular, when the organic functional group R ² is a water-insoluble functional group such as a vinyl group, an epoxy group, a methacryloxy group, a ureido group, and an isocyanate group, higher water resistance can be achieved. When the organic functional group R ² is vinyl or methacryloxy, irradiation with ionizing radiation such as ultraviolet rays or electron beams is performed in the production process. In general, water and a catalyst (acid, alkali) are used as a reaction accelerator for hydrolysis of the metal alkoxide.

For example, when a tetraalkoxysilane represented by Si (OR ¹ ) ₄ is used as the metal alkoxide, the gas barrier coating layer 3 that hardly swells even when water enters, has excellent water resistance, and has a very high barrier property. Can be obtained. In particular, when the hydrolyzable group R ¹ is a CH ₃ group or a C ₂ H ₅ group, higher water resistance and excellent barrier properties can be achieved. In general, water and a catalyst (acid, alkali) are used as a reaction accelerator for hydrolysis of the metal alkoxide.

When the metal alkoxide uses two kinds of a tetraalkoxysilane represented by the general formula Si (OR ¹ ) ₄ and a trialkoxysilane represented by the general formula R ² Si (OR ³ ) ₃ , ratio, for example, Si ^(OR _{1) 4} of SiO ₂ reduced mass and _{^{R 2 Si (OR 3) R}} 2 Si (OR 3) to the sum of the ₃ ^R 2 Si _{(OH) 3} reduced mass ₃ ^{R 2} You may set so that the ratio of Si (OH) ₃ conversion mass may be in the range of 1% to 50%. If it is smaller than 1%, the water resistance is lowered, and if it exceeds 50%, the organic functional group R ² becomes pores of the gas barrier, and the gas barrier property is lowered. The mixing ratio of the tetraalkoxysilane represented by the general formula Si (OR ¹ ) ₄ and the trialkoxysilane represented by the general formula R ² Si (OR ³ ) ₃ is such that the above ratio is 5% to 30%. You may set so that it may become in the range. In this case, the liquid content or the water-containing content can be boil sterilized or pressurized / heat sterilized, and water resistance and high barrier properties sufficient for long-term storage in a high temperature and high humidity environment can be achieved.

Of the alkoxysilanes represented by the general formula Si (OR ¹ ) ₄ , tetraethoxysilane has a hydrolysis product that can be present relatively stably in an aqueous solvent. Is relatively easy.

The alkoxysilane represented by the general formula Si (OR ¹ ) ₄ , the alkoxysilane represented by the general formula R ² Si (OR ³ ) ₃ , and water-soluble components, which are components of the coating liquid that forms the gas barrier coating layer 3. The polymers may be mixed in any order. For example, an alkoxysilane represented by the general formula Si (OR ¹ ) ₄ and an alkoxysilane represented by the general formula R ² Si (OR ³ ) ₃ were separately hydrolyzed, and then contained a water-soluble polymer. You may add these in a solution. This method is excellent in terms of dispersibility of silicon oxide and efficiency of hydrolysis.

  In the coating liquid for forming the gas barrier coating layer 3, consideration is given to improvement of wettability and adhesion to the ink or adhesive of the gas barrier coating layer 3, and prevention of cracks due to shrinkage of the gas barrier coating 3 Then, an additive may be added. As this additive, for example, clay minerals such as isocyanate compounds, colloidal silica, smectite, stabilizers, colorants, rheology modifiers, and mixtures thereof can be used.

  When the thickness of the gas barrier coating layer 3 is small, it is difficult to form the gas barrier coating layer 3 as a uniform continuous film, and sufficient gas barrier properties cannot be obtained. When the thickness is large, the film is likely to crack. The thickness of the gas barrier coating layer 3 is, for example, in the range of 0.01 μm to 50 μm.

  The coating liquid for forming the gas barrier coating layer 3 is, for example, a dipping method, a roll coating method, a gravure coating method, a reverse gravure coating method, an air knife coating method, a comma coating method, a die coating method, a screen printing method, or a spray coating method. It can be applied by a gravure offset method or the like. The coating film formed by applying this coating liquid can be dried by, for example, a hot air drying method, a hot roll drying method, a high frequency irradiation method, an infrared irradiation method, a UV irradiation method, or a combination thereof.

[Anchor coat layer]
Examples of the anchor coating agent constituting the anchor coating layer 20 formed on the gas barrier coating layer 3 when the thermoadhesive resin 21 is bonded to the transparent gas barrier film 10 by a melt extrusion lamination method include, for example, isocyanate-based (urethane Type), polyethyleneimine type, polybutadiene type, organic titanium type, and other anchor coating agents can be used.

[Thermal adhesive resin layer]
The heat-adhesive resin layer 21 formed of the melt-extruded resin in the melt-extrusion laminating method is a transparent resin layer having heat-adhesive properties. As the material of the heat-adhesive resin layer 21, resins that can be melted by heat and fused to each other can be used. Specifically, for example, low density polyethylene (LDPE), medium density polyethylene (MDPE), High density polyethylene (HDPE), linear (linear) low density polyethylene (LLDPE), polypropylene, ethylene-vinyl acetate copolymer, ionomer resin, ethylene-acrylic acid copolymer, ethylene-ethyl acrylate copolymer , Polyolefin resins such as ethylene-methacrylic acid copolymer, ethylene-methyl methacrylate copolymer, ethylene-propylene copolymer, methylpentene polymer, polybutene polymer, polyethylene or polypropylene, acrylic acid, methacrylic acid, maleic acid, Maleic anhydride, fumaric acid, itaconic acid, etc. It can be used acid-modified polyolefin resin modified with an unsaturated carboxylic acid, polyvinyl acetate resins, poly (meth) acrylic resin, polyvinyl chloride resin, a resin other like.

  An ethylene-α olefin copolymer polymerized using a metallocene catalyst (single site catalyst) can be used as the material constituting the heat-adhesive resin layer 21. As the ethylene-α-olefin copolymer polymerized using the above metallocene catalyst, for example, a catalyst using a combination of a metallocene complex and an alumoxane such as a catalyst using a combination of zirconocene dichloride and methylalumoxane, that is, a metallocene catalyst is used. Thus, an ethylene-α-olefin copolymer obtained by polymerization can be used.

  As the heat-adhesive resin layer 21, for example, one or more of the above-mentioned resins are used as a main component, and a desired additive is arbitrarily added to the resin composition to prepare a resin composition. Using the prepared resin composition, for example, a film is formed by using a molding method such as a T-die method, an inflation method, or the like, or a melt-extruded coating film is formed. Can be configured. In the above, it is preferable that the heat-adhesive resin layer 21 is excellent in low odor and scent retention etc. with respect to the contents, is excellent in strength and the like, and can improve the waist as a bag. Is.

The thickness of the heat-adhesive resin layer 21 is preferably about 10 μm to 100 μm, and more preferably about 20 μm to 60 μm. The heat-adhesive resin layer 21 may have a two-layer structure of a first extruded resin and a second extruded resin, or a three-layer structure in which an intermediate film layer is provided.
However, the first extruded resin directly formed on the transparent gas barrier film 10 is preferably 20 μm or less, and if the film is formed 20 μm or more, the gas barrier coating layer 3 is deteriorated and good gas barrier properties cannot be obtained. The second extruded resin is preferably 40 μm or less for the same reason.

  A printing ink layer or the like may be interposed between the transparent gas barrier film 10 and the heat-adhesive resin layer 21 depending on applications and requirements.

(Print layer)
The printed layer is formed for practical use as a packaging bag, etc., and various pigments are added to conventionally used ink binder resins such as urethane, acrylic, nitrocellulose, rubber and vinyl chloride. , A layer composed of an ink to which additives such as extender pigments, plasticizers, desiccants, stabilizers and the like are added, and characters, patterns, etc. are formed. As a forming method, for example, a known printing method such as an offset printing method, a gravure printing method, a silk screen printing method, or the like can be used. The thickness is preferably 0.1 to 2.0 μm.

<Method of manufacturing a liquid filling bag>
Next, a description will be given of a method for manufacturing the liquid filling bag by bag-making the laminated body 40 produced as described above. For example, using the laminated body 40 produced by the above-described method, The heat-adhesive resin layer 21 faces each other and is folded or overlapped, or two of them are overlapped, and the peripheral end portions thereof are heat-sealed to provide a seal portion, so that liquids having various forms A filling bag can be produced. As the bag making method, the above laminated body is folded with its inner layer faces facing each other, or two of them are overlapped, and the peripheral edge of the outer periphery is, for example, a side seal type, two-way seal Heat-sealed by seal type such as mold, three-side seal type, four-side seal type, envelope sticker seal type, jointed seal type (pillow seal type), pleated seal type, flat bottom seal type, square bottom seal type, etc. Various types of liquid filling bags according to the present invention can be manufactured. In addition, for example, a self-supporting packaging bag (standing pouch) or the like can be manufactured.

  The liquid filling bags produced as described above are, for example, soups, soups, soy sauce, sauces, soup stocks, spices, cooking liquors, etc. It can be filled and packaged with various liquid or viscous foods such as others. Furthermore, in addition to the food and drink as described above, the liquid filling bag is used for filling and packaging various articles such as chemicals such as adhesives and pressure-sensitive adhesives, cosmetics, pharmaceuticals, and the like.

  The liquid sachet package 30 constituted by the transparent gas barrier film 10 and the heat-adhesive resin layer 21 is particularly excellent in gas barrier properties and impairs the flavor and taste of the contents during storage, storage or distribution. There is nothing. Furthermore, in the present invention, the liquid filling bag prevents the generation of harmful gases such as chlorine gas even when it is disposed of as trash and subjected to combustion treatment, and is a liquid suitable for extremely excellent environmental measures. It has the advantage that a small bag package can be manufactured.

  Hereinafter, the present invention will be described in more detail with reference to examples.

<Example 1>
A transparent vapor-deposited thin film layer formed of aluminum oxide having a thickness of 30 nm is laminated on a biaxially stretched polyester film containing 60% of a polybutylene terephthalate component having a thickness of 15 μm as a base film 1 by a vacuum vapor deposition apparatus using an electron beam heating method. did. Further, a gas barrier coating solution having the following composition is applied on the transparent vapor-deposited thin film layer by a gravure coating method, heated and dried, and a gas barrier coating layer having a thickness of 0.3 μm is laminated, thereby forming a transparent gas barrier film. Got.

(Adjustment of gas barrier coating solution)
The gas barrier coating solution was prepared as follows.
(A) Tetraethoxysilane (Si (OC ₂ H ₅ ) ₄ ; hereinafter abbreviated as TEOS) 17.9 g and 10 g of methanol were added 72.1 g of 0.1N hydrochloric acid and stirred for 30 minutes to hydrolyze the solid content. 5% (weight ratio in terms of SiO ₂ ) hydrolysis solution.
(B) A 5% (weight ratio), water / methanol = 95/5 (weight ratio) solution of polyvinyl alcohol (hereinafter abbreviated as PVA).
(C) 1,3,5-tris (3-trialkoxysilylalkyl) isocyanurate in water / isopropyl alcohol = 1/1 solution to a solid content of 5% (weight ratio R ₂ Si (OH) ₃ conversion) Adjusted hydrolysis solution.
Gas barrier coating solution used in Example 1 by mixing the mixing ratios of the solutions (a) to (c) so that the ratio of liquid a / liquid b / liquid c = 70/20/10 (solid content weight ratio). Got.

Furthermore, on the gas barrier coating layer of the transparent gas barrier film, a two-pack type aromatic ester anchor coating agent (mixed so as to have a solid content of 5% by A3210 / A3075 manufactured by Mitsui Chemicals) is applied by a gravure coating method. After drying by heating, a linear low density polyethylene resin (density: 0.919 g / cm ³ , MFR: 5.1 g / 10 min.) Was obtained by extrusion extrusion laminating at an extrusion temperature of 340 ° C. A heat-adhesive resin having a total thickness of 60 μm composed of two layers of 20 μm and 40 μm was formed into a transparent gas barrier laminate.
This transparent gas barrier laminate was measured for heat shrinkage at 150 ° C. for 30 minutes and found to be 2.0% in the MD direction (flow direction).
Two sheets of the above-mentioned laminate are prepared, and the surfaces of the heat-adhesive resin layer located in the innermost layer are opposed to each other, and then the three sides of the outer periphery are heat-sealed to form a three-side seal type The liquid filling bag was manufactured, and then the water was filled from the opening, and then the opening was heat-sealed and sealed to obtain the liquid pouch package of the present invention.

<Example 2>
A transparent gas barrier film was prepared in the same manner as in Example 1 except that a linear low density polyethylene resin having a total thickness of 40 μm composed of two layers of extruded resin thicknesses of 20 μm and 20 μm was used. A transparent gas barrier laminate was obtained by elution extrusion lamination. Using the transparent gas barrier laminate, a liquid sachet package was obtained in the same manner as in Example 1.

<Example 3>
A transparent gas barrier film was prepared in the same manner as in Example 1 except that a linear low-density polyethylene resin having a total thickness of 20 μm consisting of two layers of 10 μm and 10 μm in thickness of the extruded resin of Example 1 was used. A transparent gas barrier laminate was obtained by elution extrusion lamination. Using the transparent gas barrier laminate, a liquid sachet package was obtained in the same manner as in Example 1.

<Example 4>
A transparent gas barrier film was prepared in the same manner as in Example 1 except that a biaxially stretched polyester film containing 80% of a polybutylene terephthalate component having a thickness of 15 μm was used as the base film 1. A transparent gas barrier laminate was obtained by a lamination method. Using the transparent gas barrier laminate, a liquid sachet package was obtained in the same manner as in Example 1.

<Comparative Example 1>
A transparent gas barrier film was prepared in the same manner as in Example 1 except that a polyethylene terephthalate (PET) film (Toray P60) having a thickness of 12 μm was used as the base film 1 in Example 1 and was eluted in the same manner as in Example 1. A transparent gas barrier laminate was obtained by an extrusion lamination method. Using the transparent gas barrier laminate, a liquid sachet package was obtained in the same manner as in Example 1.

<Comparative Example 2>
A transparent gas barrier film was prepared in the same manner as in Example 1 except that a polyamide film (ONM manufactured by Unitika) having a thickness of 15 μm was used as the base film 1 in Example 1, and the elution extrusion lamination method was used in the same manner as in Example 1. A transparent gas barrier laminate was obtained. Using the transparent gas barrier laminate, a liquid sachet package was obtained in the same manner as in Example 1.

<Comparative Example 3>
A transparent gas barrier film was prepared in the same manner as in Example 1 except that a linear low-density polyethylene film obtained by forming the extruded resin of Example 1 at a thickness of 60 μm at a time was used. A transparent gas barrier laminate was obtained by a lamination method. Using the transparent gas barrier laminate, a liquid sachet package was obtained in the same manner as in Example 1.

<Comparative example 4>
A transparent gas barrier film was prepared in the same manner as in Example 1 except that a linear low density polyethylene resin having a total thickness of 100 μm consisting of two layers of extruded resin thicknesses of 20 μm and 80 μm in Example 1 was used. A transparent gas barrier laminate was obtained by elution extrusion lamination. Using the transparent gas barrier laminate, a liquid sachet package was obtained in the same manner as in Example 1.

<Comparative Example 5>
A transparent gas barrier film was prepared in the same manner as in Example 1 except that a biaxially stretched polyester film containing 20% of a polybutylene terephthalate component having a thickness of 15 μm was used as the base film 1. A transparent gas barrier laminate was obtained by a lamination method. Using the transparent gas barrier laminate, a liquid sachet package was obtained in the same manner as in Example 1.

  About the liquid sachet packaging body which consists of a transparent gas barrier laminated body obtained in Examples 1-4 and Comparative Examples 1-5, it is water-cooled (20 degreeC 5 minutes after a thermal contraction rate and boiling sterilization treatment (95 degreeC 90 minutes). ), The oxygen permeability and water vapor permeability were measured, and the puncture strength was measured. Further, a filling test was carried out to confirm filling suitability, and comprehensive practicality was judged. The evaluation results are shown in Table 1.

<Measurement of thermal shrinkage>
The length of the film before and after heating was measured in at least one direction when the transparent gas barrier films obtained in Examples and Comparative Examples were heated in a thermostatic bath at 150 ° C. for 30 minutes. Shrinkage was calculated.
(Length before heating−length after heating) / length before heating × 100 (%) (1)

<Measurement of oxygen permeability>
The transparent gas barrier films obtained in Examples and Comparative Examples were measured under the conditions of 30 ° C. and 70% RH environment using Modern 2/21 made by Modern Control in accordance with JIS K-7126-2 method. It was.

<Measurement of water vapor transmission rate>
In accordance with JIS K-7129-B method, the transparent gas barrier films obtained in the examples and comparative examples were measured under the conditions of 40 ° C. and 90% RH environment using Permatran W3 / 33 manufactured by Modern Control. went.

<Measurement of puncture strength>
The transparent gas barrier films obtained in Examples and Comparative Examples were fixed to a piercing measurement jig, and a semicircular needle having a diameter of 1.0 mm and a tip shape radius of 0.5 mm was formed on the base material surface at 50 ± 0 per minute. The needle was pierced at a speed of 5 mm, and the load until the needle penetrated was measured.

<Filling suitability evaluation>
Using the winding of the transparent gas barrier film obtained in Examples 1 to 4 and Comparative Examples 1 to 5, filling is performed with a liquid / viscous high-speed filling machine (NT-DANGANTYPE3 manufactured by Taisei Lamic Co., Ltd.), and a liquid sachet package is obtained. Was made. Filling is pouch size 120mm (length) x 90mm (width), speed 9mm / min, contents about 80g, seal temperature length 182 ° C / width 165 ° C, seal pressure length left 160kPa / length right 80kPa / width left 380kPa / width right It was performed at 350 kPa. As for the evaluation criteria, the appearance finish and the presence or absence of liquid leakage were confirmed. The case where there was no problem was marked as ◯, and the case where there was a problem in at least one was marked as x.

As can be seen from Table 1, the packaging material for liquid sachets of the present invention in Example 1 is excellent not only in oxygen permeability but also in water vapor permeability, and has excellent puncture strength properties and pinhole resistance. It was confirmed that there is. From these, when applied to liquid contents and moisture-containing contents that require high strength physical properties, there is a low possibility of occurrence of bag breakage, and a liquid pouch package satisfying the required practical performance is obtained. I was able to. In addition, when a filling test was conducted with a high-speed liquid / viscous filling machine, it was judged that there was no liquid leakage and the appearance was good.

  In Examples 2 and 3, the thickness of the extruded resin was made as thin as 40 μm and 20 μm as compared with Example 1, but it was confirmed that all had various physical properties equivalent to Example 1.

  In Example 4, the polybutylene terephthalate component, which is a base material, was increased to 80% from Example 1, and as a result, it was confirmed that the material had better puncture strength properties than Example 1.

  In contrast, in Comparative Example 1, the oxygen permeability and water vapor permeability were good, but the puncture strength was low and sufficient practical performance could not be obtained. In Comparative Example 2, sufficient puncture strength was confirmed, but the oxygen permeability and water vapor permeability were poor, and there was a concern that the contents were oxidized and changed due to moisture evaporation.

  In Comparative Example 3, since the heat-adhesive resin was extruded at 60 μm at a time, excessive heat was applied to the gas barrier coating layer to cause cracks, and the oxygen permeability and water vapor permeability deteriorated to obtain sufficient practical performance. There wasn't. In Comparative Example 4, since the second extruded resin constituting the heat-adhesive resin was formed at 80 μm, as in the comparative example, excessive heat was applied to the gas barrier coating layer, resulting in sufficient barrier performance. I couldn't.

  Further, in Comparative Example 5, the PBT component ratio was 20%, which is a ratio of half or less, the puncture strength was nearly equal to that of the PET base material, and there was a concern about pinhole resistance.

  From the above results, the liquid sachet package having excellent gas barrier properties that prevent permeation of oxygen gas, water vapor, etc. has gas barrier properties and pinhole resistance, and also has excellent liquid filling properties. I realized that it could be realized.

DESCRIPTION OF SYMBOLS 1 ... Base film 2 ... Inorganic oxide layer 3 ... Gas barrier film layer 10 ... Transparent gas barrier film 20 ... Anchor coat layer 21 ... Thermal adhesive resin layer 30 ... Liquid pouch packaging 31 ... Heat seal part 32 ... Opening part ( Heat seal part)
33 ... Contents

Claims (6)

A heat sealable laminate,
A transparent gas barrier film and a heat-adhesive resin layer;
The transparent gas barrier film comprises at least a base film containing a polyester resin mainly composed of a butylene terephthalate unit, one or more inorganic oxide layers, and a gas barrier coating layer in this order.
The thermal adhesive resin layer is a thermal adhesive resin layer having a thickness of 20 μm or more and 60 μm or less laminated on the gas barrier coating layer.
A laminate having a heat shrinkage ratio of 1.0 or more and less than 3.0% represented by the following formula (1) after heating at 150 ° C. for 30 minutes in at least one direction.
(Length before heating−length after heating) / length before heating × 100 (%) (1)   The laminate according to claim 1, wherein at least one of AL and Si is contained in at least one of the inorganic oxide layers.   The laminate according to claim 1 or 2, wherein the gas barrier coating layer is a layer containing a water-soluble polymer and an inorganic oxide.   The laminate according to any one of claims 1 to 3, wherein an anchor coat layer is provided between the gas barrier coating layer and the heat-adhesive resin layer.   The laminate having excellent gas barrier properties according to any one of claims 1 to 4, wherein the heat-adhesive resin layer is a heat-adhesive resin layer having heat sealability.   A packaging bag comprising the laminate according to any one of claims 1 to 5.