JP5933309B2 - Straight cut gas barrier package - Google Patents

Description

  The present invention relates to a package having excellent oxygen barrier properties, linear cut properties and laminate strength.

In order to prevent food deterioration and store for a long period of time, it is essential to use a package having excellent gas barrier properties for the packaging. As a material for packaging food, plastic films are generally used. However, plastic films that have insufficient gas barrier performance by themselves can be laminated with other films that have been provided with gas barrier performance. A package is produced by making a package or by bonding it with a film having high gas barrier performance.
However, a package obtained by laminating a plastic film may not be opened by tearing linearly, and may leak if the contents are liquid when opened obliquely.

  For this reason, a biaxially stretched polyamide film (Patent Document 1) and a biaxially stretched polyester film (Patent Document 2) have been proposed as films having improved tearability. Although the opening of the package is improved by using these films, since these films themselves do not have gas barrier properties, it is necessary to laminate them with a film having gas barrier properties when used in a package. There was a problem of cost increase. In addition, there is a problem that the lamination strength is reduced during lamination, delamination occurs during tearing, and tear resistance increases.

JP-A-10-230540 Japanese Patent Laid-Open No. 10-168293

  An object of the present invention is to solve the above-mentioned problems, and to provide a package that is excellent in oxygen barrier properties, linear cut properties, and laminate strength.

As a result of intensive studies to solve the above problems, the present inventors have laminated the gas barrier layer having a specific composition on a biaxially stretched film having a specific resin composition and a linear cut property. The inventors have found that the problem is solved and have reached the present invention.
That is, the gist of the present invention is as follows.
(1) A biaxially stretched film (I) having a linear cut property in the longitudinal direction of the film, a gas barrier layer (II), a laminate adhesive layer (III), and a sealant layer (IV) are laminated in this order. The biaxially stretched film (I) contains nylon 6 and poly (metaxylylene adipamide), and their mass ratio [nylon 6 / poly (metaxylylene adipamide)] is The film is 80/20 to 95/5, or the biaxially stretched film (I) contains polyethylene terephthalate (PET) and modified polybutylene terephthalate (modified PBT), and their mass ratio [PET / modified PBT] is 70/30 to 95/5, and the modified PBT contains 5 to 20% by mass of a polytetramethylene glycol unit having a molecular weight of 600 to 4000. The gas barrier layer (II) contains the inorganic layered compound (A) and the resin (B), and the volume ratio [inorganic layered compound (A) / resin (B)] is 3 / 97-7 / 93 is a straight-cut gas barrier package.
(2) In the laminate including the biaxially stretched film (I) and the gas barrier layer (II), the oxygen permeability converted per 1 μm thickness of the gas barrier layer (II) is 2 ml at 20 ° C. and 65% RH. The linear-cutting gas barrier package according to (1), which is / m ² · day · MPa or less.
(3) The straight-cut gas barrier package according to (1) or (2), wherein the thickness of the gas barrier layer (II) is 0.1 to 1 μm.
(4) The linear cut gas barrier package according to any one of (1) to (3), wherein the laminate has a laminate strength of 3.5 N / cm or more.
(5) The straight-cut gas barrier packaging according to any one of (1) to (4), wherein the inorganic layered compound (A) has an average particle size of 5 μm or less and an aspect ratio of 50 to 5000. body.
(6) The straight cut gas barrier package according to any one of (1) to (5), wherein the resin (B) is a high hydrogen bond resin.
(7) The straight-cut gas barrier package according to (6), wherein the high hydrogen bonding resin is polyvinyl alcohol.

Since the biaxially stretched film (I) which consists of a specific resin composition is laminated | stacked, the package of this invention is excellent in the linear cut property of a film longitudinal direction. Further, the gas barrier layer (II) laminated on the package of the present invention contains the inorganic layered compound (A) and the resin (B) at a specific volume ratio. And has bending resistance, so that when the package is torn, delamination does not occur in the package.
Therefore, the package of the present invention is excellent in gas barrier properties and can prevent deterioration of the contents, and when opened, it can be easily torn apart and no delamination occurs.
In addition, since the packaging body of the present invention has a specific composition for the film constituting the laminate, it is not necessary to invest in equipment or increase the labor of processing, and the problem of cost increase due to these can be avoided. .

Hereinafter, the present invention will be described in detail.
The package of the present invention comprises a biaxially stretched film (I) having a linear cut property in the longitudinal direction of the film, a gas barrier layer (II), a laminate adhesive layer (III), and a sealant layer (IV). It is the laminated body laminated | stacked in order.

[Biaxially stretched film (I) having linear cut property in the longitudinal direction of the film]
In the package of the present invention, the biaxially stretched film (I) having a linear cut property in the longitudinal direction of the film is a biaxially stretched polyamide film having a linear cut property in the longitudinal direction from the viewpoint of strength as a package. Alternatively, a biaxially stretched polyester film can be used.
In addition, in this invention, a longitudinal direction means the direction perpendicular | vertical to the width direction (TD) of a film, ie, the direction (MD) of the production line at the time of film forming. The biaxially stretched film (I) in the present invention is easy to tear linearly in the MD direction.

The biaxially stretched polyamide film having a linear cut property in the longitudinal direction in the present invention needs to be a biaxially stretched polyamide film containing nylon 6 and poly (metaxylylene adipamide) (MXD6). .
The mass ratio of nylon 6 and MXD6 in the biaxially stretched polyamide film needs to be nylon 6 / MXD6 = 80/20 to 95/5. When MXD6 is more than 20% by mass, operational problems such as fluctuations in film thickness are likely to occur, and when MXD6 is less than 5% by mass, the film cannot have a linear cut property.

  The nylon 6 constituting the biaxially stretched polyamide film preferably has a relative viscosity of 2.5 to 4.0, and more preferably 2.9 to 3.3. When the relative viscosity is less than 2.5, the dispersed particle size of MXD6 increases, and the linear cut property of the resulting film decreases. When the relative viscosity is greater than 4.0, the film is formed by extrusion. Sex is reduced.

The poly (metaxylylene adipamide) (MXD6) constituting the biaxially stretched polyamide film preferably has a relative viscosity of 2.0 to 3.0, and preferably 2.3 to 2.5. More preferred. When the relative viscosity is less than 2.0, the formation of dispersed particles of MXD6 in nylon 6 is hindered, the linear cut property of the resulting film is lowered, and when the relative viscosity is greater than 3.0. In this case, the dispersed particle size of MXD6 is increased, and the linear cut property is lowered.
Note that MXD6 may contain a paraxylylene adipamide component of about 5% by mass or less as long as the effects of the present invention are not impaired.

  The biaxially stretched polyamide film may be blended with other polyamides within the range not impairing the effects of the present invention, or may be blended with various inorganic and organic additives usually used for polyamide resins. Inorganic additives include lubricants such as talc, silica, alumina, magnesia, calcium carbonate, and antioxidants such as copper halides, and organic additives include crystal nuclei such as ε-capramide dimer and graphite. Examples thereof include an antioxidant, an aromatic amine, an antioxidant such as hindered phenol, and a film modifier such as a modified polyolefin.

  In order to produce a biaxially stretched polyamide film having a linear cut property in the longitudinal direction, for example, a mixture of nylon 6 and MXD6 is put into an extruder, heated and melted, and then extruded into a film form from a T die. An unstretched film is produced. Next, the film extruded from the T-die is cooled by tightly winding and cooling a cooling drum that is rotated by a known casting method such as an air knife casting method or an electrostatic application casting method, at a stretching temperature of 160 to 190 ° C. It is obtained by stretching at a magnification of about 2.8 to 3.8 times in the vertical and horizontal directions, and further heat-treating at a temperature of 150 to 220 ° C. The biaxial stretching method is not particularly limited, and any of a tenter simultaneous biaxial stretching method and a sequential biaxial stretching method using a roll and a tenter may be used. Moreover, you may manufacture a biaxially stretched film with a tubular method.

In the present invention, as the biaxially stretched film (I) having a linear cut property in the longitudinal direction of the film, a biaxially stretched polyester film can be used in addition to the biaxially stretched polyamide film.
In the present invention, the biaxially stretched polyester film having a linear cut property in the longitudinal direction needs to be a biaxially stretched polyester film containing polyethylene terephthalate (PET) and polybutylene terephthalate (modified PBT).
And the mass ratio of PET and modified PBT in the biaxially stretched polyester film needs to be PET / modified PBT = 70/30 to 95/5, preferably 80/20 to 90/10, 85 More preferably, it is / 15 to 90/10. When the amount of the modified PBT is more than 30% by mass, not only the thickness fluctuation of the film becomes large and the linear cut property of the obtained film is lowered, but also the performance such as mechanical strength, dimensional stability and haze is lowered. Problems arise in practical performance. Moreover, when there is less modified | denatured PBT than 5 mass%, a linear cut property is not acquired on a film.

PET constituting the biaxially stretched polyester film is obtained by a known production method, that is, after obtaining an oligomer by a transesterification method from dimethyl terephthalate and ethylene glycol or a direct esterification method from terephthalic acid and ethylene glycol. , Obtained by melt polymerization or further solid phase polymerization, and may be obtained by copolymerization of other components.
Other copolymer components include isophthalic acid, phthalic acid, 2,6-naphthalenedicarboxylic acid, 5-sodium sulfoisophthalic acid, succinic acid, adipic acid, sebacic acid, dodecanedioic acid, dimer acid, maleic anhydride, maleic acid Acids, fumaric acid, itaconic acid, citraconic acid, mesaconic acid, dicarboxylic acids such as cyclohexanedicarboxylic acid, 4-hydroxybenzoic acid, ε-caprolactone, oxycarboxylic acids such as lactic acid, 1,3-propanediol, 1,6- Examples thereof include glycols such as hexanediol and cyclohexanedimethanol, and polyfunctional compounds such as trimellitic acid, trimesic acid, pyromellitic acid, trimethylolpropane, glycerin, and pentaerythritol.

  The modified PBT constituting the biaxially stretched polyester film needs to be polybutylene terephthalate containing 5 to 20% by mass of a polytetramethylene glycol (PTMG) unit having a molecular weight of 600 to 4000.

  The molecular weight of PTMG needs to be 600 to 4000, preferably 1000 to 3000, and more preferably 1000 to 2000. When the molecular weight of PTMG is less than 600, the linear cut property cannot be obtained, and when the molecular weight exceeds 4000, the performance such as mechanical strength, dimensional stability, haze, etc. is lowered, and a stable film straight line is obtained. Cutability does not appear.

  The content of the PTMG unit in the modified PBT needs to be 5 to 20% by mass, preferably 10 to 20% by mass, and more preferably 10 to 15% by mass. When the content of PTMG is less than 5% by mass, the resulting film does not exhibit linear cutability, and when the content exceeds 20% by mass, the mechanical strength of the resulting film, dimensional stability, Performance such as haze decreases, and it becomes difficult to obtain a stable linear cut property of the film. In addition, when the content of PTMG exceeds 20% by mass, a phenomenon in which the film pulsates during extrusion (so-called ballast phenomenon) may occur, particularly when produced on a mass production scale. A problem occurs.

  Modified PBT can be obtained by polycondensation by adding PTMG in the PBT polymerization step, but as a simpler method, it can also be obtained by melt-kneading PBT and PTMG with an extruder.

  In the present invention, the biaxially stretched polyester film is a known various additives such as other polymers, lubricants, inorganic particles, organic particles, antioxidants, antistatic agents, as long as the effects of the present invention are not impaired. An ultraviolet absorber, a surfactant, a pigment, a fluorescent brightening agent, and the like may be included. Examples of other polymers include polyethylene naphthalate, polycyclohexylene dimethylene terephthalate, and the like, as the lubricant, inactive particles having an average particle diameter of 0.1 to 4 μm from the viewpoint of anti-blocking property and transparency of the film, For example, silica or the like is added in an amount of 0.005 to 1.0% by mass, preferably 0.01 to 0.5% by mass, and inorganic particles include silica, calcium carbonate, titanium oxide, and the like. Examples of the particles include acrylic and styrene.

  In order to produce a biaxially stretched polyester film having a linear cut property in the longitudinal direction, for example, a mixture of PET and modified PBT is put into an extruder, heated and melted, and then extruded from a T die into a film shape. An unstretched film is produced. Next, the film extruded from the T-die is tightly wound around a rotating drum that is rotated by a known casting method such as an air knife casting method or an electrostatic application casting method, and is cooled. Each is stretched at a magnification of 3.0 to 5.0 times, and further heat treated at a temperature of 210 to 245 ° C. The biaxial stretching method is not particularly limited, and any of a tenter simultaneous biaxial stretching method and a sequential biaxial stretching method using a roll and a tenter may be used. Moreover, you may manufacture a biaxially stretched film with a tubular method.

  The thickness of the biaxially stretched film (I) such as the biaxially stretched polyamide film or the biaxially stretched polyester film is not particularly limited, but is suitable as a packaging material and may be laminated with other layers. Considering this, it is preferably 3 to 200 μm for practical use, and preferably 6 to 30 μm depending on the application.

[Anchor coat layer]
In the package of the present invention, the gas barrier layer (II) is laminated on the biaxially stretched film (I), but the gas barrier layer (II) is formed after the anchor coat layer is formed on the biaxially stretched film (I). It may be laminated. By interposing the anchor coat layer, the adhesion between the biaxially stretched film (I) and the gas barrier layer (II) can be improved.

  A method for forming the anchor coat layer on the biaxially stretched film (I) is not particularly limited, but a coating method using an anchor coat agent that is a solution in which a material for forming the anchor coat layer is dispersed or dissolved in a solvent. It is preferable to form by.

As the anchor coating agent, known ones can be used without any particular limitation, and examples thereof include isocyanate, polyurethane, polyester, polyethyleneimine, polybutadiene, polyolefin, and alkyl titanate. Among these, in view of the effects of the present invention, an isocyanate-based, polyurethane-based, or polyester-based anchor coating agent is preferable, and a mixture of one or more of isocyanate compounds, polyurethanes, and urethane prepolymers, and reaction products, polyesters. It is preferably a mixture and reaction product of one or more of polyol and polyether and isocyanate and a solution or dispersion thereof.
Solvents constituting the anchor coating agent include water, alcohols such as methanol, ethanol and isopropanol, cellosolves such as butyl cellosolve, toluene, MEK, cyclohexanone, sorbeso, isophorone, xylene, MIBK, ethyl acetate, propyl acetate, butyl acetate And organic solvents such as

  Roll coating methods such as direct gravure method, reverse gravure method, micro gravure method, two roll beat coat method, bottom feed three reverse coat method, etc. are applied as methods for applying the anchor coating agent on the biaxially stretched film (I). And a doctor knife method, a die coating method, a dip coating method, a bar coating method, and a coating method combining these methods. Although it does not specifically limit as a method of drying after application | coating, The method of using dryers, such as the method of drying in oven and various dryers, is mentioned, As drying conditions, 30-260 degreeC, 0.5-60 Minutes.

  Although the application | coating thickness of an anchor coating agent is not specifically limited, It is preferable that dry thickness is 0.02-0.2 micrometer, and it is more preferable that it is 0.04-0.1 micrometer.

[Gas barrier layer (II)]
The gas barrier layer (II) in the present invention needs to contain the inorganic layered compound (A) and the resin (B), and the volume ratio of the inorganic layered compound (A) to the resin (B) [inorganic layered compound ( A) / resin (B)] is required to be 3/97 to 7/93, preferably 3/97 to 5/95, and more preferably 4/96 to 5/95. .
The greater the volume ratio of the inorganic layered compound (A), the better the oxygen barrier property of the gas barrier layer (II). However, when the volume ratio of the inorganic stratiform compound (A) in the gas barrier layer (II) exceeds 7% by volume, the gas barrier layer (II) becomes hard and brittle, resulting in lower flex resistance. As a result, the packaging body in which the laminate adhesive layer (III) and the sealant layer (IV) are sequentially laminated on the gas barrier layer (II) is delaminated when tearing and cannot be easily torn. . In the present invention, by setting the volume ratio of the inorganic layered compound (A) in the gas barrier layer (II) to 7% by volume or less, the laminate strength (X) of the resulting package can be set to 3.5 N / cm or more. Preferably 3.55 N / cm or more, more preferably 3.6 N / cm or more. When the laminated strength (X) of the package is 3.5 N / cm or more, delamination or unsuccessful opening is unlikely to occur when the packaging bag is opened, and the packaging bag is formed and filled with the contents. No delamination or bag breakage occurs during subsequent sterilization or transport.
On the other hand, if the volume ratio of the inorganic layered compound (A) is less than 3% by volume, high oxygen barrier properties cannot be obtained even if the thickness of the gas barrier layer (II) is increased. That is, in the laminate including the biaxially stretched film (I) and the gas barrier layer (II), the oxygen permeability converted per 1 μm thickness of the gas barrier layer (II) is 2 ml / min at 20 ° C. and 65% RH. It may not be less than m ² · day · MPa, and the high oxygen barrier property that is a feature of the present invention cannot be obtained. In order to preserve food for a long period of time, the oxygen permeability is preferably ² ml / m ² · day · MPa or less.

The thickness of the gas barrier layer (II) is not particularly defined, but is preferably 0.1 to 1 μm, more preferably 0.2 to 0.7 μm, and more preferably 0.25 to 0. More preferably, it is 5 μm. If the thickness of the gas barrier layer (II) is less than 0.1 μm, the expression of gas barrier properties may be insufficient. If the thickness exceeds 1 μm, the required transparency cannot be obtained depending on the application, In addition, the manufacturing cost is not preferable.
The number of gas barrier layers (II) may be increased as necessary.

  Further, the gas barrier layer (II) may be mixed with various additives such as an ultraviolet absorber, a colorant, and an antioxidant as long as the effects of the present invention are not impaired.

<Inorganic layered compound (A)>
The “inorganic layered compound” constituting the gas barrier layer (II) refers to an inorganic compound in which unit crystal layers are stacked to form a layered structure. In other words, the “layered compound” is a compound or substance having a layered structure, and the “layered structure” is a van der Waals surface in which atoms are strongly bonded by covalent bonds or the like and closely arranged. A structure that is stacked in parallel by weak binding force such as force.

  As the inorganic layered compound (A), a clay mineral having a swelling property and a cleavage property in a solvent can be particularly preferably used. Such clay minerals include kaolinite, dickite, nacrite, halloysite, antigolite, chrysotile, pyrophyllite, montmorillonite, beidellite, bentonite, nontronite, saponite, sauconite, stevensite, hectorite, tetrasilic mica. Sodium teniolite, muscovite, margarite, talc, vermiculite, phlogopite, xanthophyllite, chlorite and the like. Among these, smectite group, vermiculite group, and mica group clay minerals are preferable, and the smectite group is particularly preferable. Examples of the smectite group include montmorillonite, beidellite, nontronite, saponite, soconite, stevensite, and hectorite. However, it is not particularly limited. In addition, those obtained by treating these clay minerals with an organic substance such as ion exchange to improve dispersibility can also be used as the inorganic layered compound. When the inorganic layered compound (A) is a clay mineral having swelling properties, it is excellent in water resistance (barrier properties after a water-resistant environmental test).

The inorganic layered compound (A) preferably has an average particle size of 5 μm or less from the viewpoints of gas barrier properties, transparency, and film forming properties. Particularly in applications where transparency is required, the average particle size is more preferably 1 μm or less.
The aspect ratio of the inorganic layered compound (A) is preferably 50 to 5000, and more preferably 200 to 3000. If the aspect ratio is less than 50, the gas barrier property is not sufficiently developed. On the other hand, an inorganic layered compound having an aspect ratio of more than 5000 is technically difficult to obtain, and is costly and economically expensive. Therefore, from the viewpoint of ease of manufacture, this aspect ratio is preferably 3000 or less.

<Resin (B)>
The resin (B) constituting the gas barrier layer (II) is not particularly limited. For example, polyvinyl alcohol (PVA), ethylene-vinyl alcohol copolymer (EVOH), polyacrylonitrile (PAN), polysaccharide, polyacrylic acid And esters thereof.

Preferred examples of the resin (B) include a resin having a hydrogen bonding group or an ionic group, and the content of the hydrogen bonding group or the ionic group is 20 to 60% by mass with respect to the resin. A hydrogen bonding resin is preferable, and the content of the hydrogen bonding group or the ionic group is more preferably 30 to 50% by mass with respect to the resin. When the resin (B) is a high hydrogen bond resin, it is excellent in water resistance (barrier property after a water resistance environment test).
The “hydrogen bonding group” refers to a group having at least one hydrogen bonded directly to an atom (hetero atom) other than carbon. The “ionic group” refers to a group having at least one “positive or negative” charge that is localized to the extent that water molecules can be hydrated in water.
Examples of the hydrogen bonding group include a hydroxyl group, an amino group, a thiol group, a carboxyl group, a sulfonic acid group, and a phosphoric acid group. Examples of the ionic group include a carboxylate group, a sulfonic acid ion group, a phosphate ion group, and an ammonium group. And phosphonium groups, and more preferable examples include a hydroxyl group, an amino group, a carboxyl group, a sulfonic acid group, a carboxylate group, a sulfonic acid ion group, and an ammonium group.

Specific examples of the high hydrogen bonding resin include, for example, polyvinyl alcohol and its analogs, vinyl alcohol resins such as ethylene-vinyl alcohol copolymer having a vinyl alcohol fraction of 40 mol% or more; cellulose, hydroxymethyl cellulose, hydroxy Cellulose derivatives such as ethyl cellulose and carboxymethyl cellulose, polysaccharides such as amylose, amylopectin, pullulan, curdlan, xanthan, chitin, chitosan and cellulose; polyacrylic acid, sodium polyacrylate, poly-2-hydroxyethyl acrylate, poly-2 -Acrylic resins such as hydroxyethyl methacrylate, polyacrylamide, ethylene-acrylic acid copolymer and salts thereof; polyaminoamides such as diethylenetriamine-adipic acid polycondensate Resin, polystyrene sulfonic acid, sodium polystyrene sulfonate, polyvinyl pyridine and its salt, polyethyleneimine and its salt, polyallylamine and its salt, polyvinyl pyrrolidone, polyvinyl sulfonic acid and its salt, polyvinyl thiol, polyethylene glycol, polypropylene glycol, polyglycerin Examples thereof include a resin having a hydrogen bonding group or an ionic group in the molecule.
The high hydrogen bonding resin is preferably polyvinyl alcohol and an ethylene-vinyl alcohol copolymer having a vinyl alcohol fraction of 40 to 80 mol%.

Polyvinyl alcohol is a polymer having a monomer unit of vinyl alcohol as a main component. As such “polyvinyl alcohol”, for example, a polymer obtained by hydrolysis or transesterification (saponification) of an acetate portion of a vinyl acetate polymer (to be exact, a copolymer of vinyl alcohol and vinyl acetate was obtained. And a polymer obtained by saponifying a vinyl trifluoroacetate polymer, a vinyl formate polymer, a vinyl pivalate polymer, a t-butyl vinyl ether polymer, a trimethylsilyl vinyl ether polymer, etc. For details, see, for example, edited by Poval Society, “World of PVA”, 1992, Kobunshi Publishing Co., Ltd .; Nagano et al., “Poval”, 1981, Kobunshi Publishing Co., Ltd. ). The degree of “saponification” in polyvinyl alcohol is preferably 70% or more, more preferably 85% or more, and more preferably 98% or more of a so-called fully saponified product in terms of mole percentage. The degree of polymerization is more preferably 100 to 5000 and 200 to 3000.
The ethylene-vinyl alcohol copolymer (EVOH) preferably has a vinyl alcohol fraction of 40 to 80 mol%, more preferably 45 to 75 mol%. The melt index of EVOH (value measured under conditions of a temperature of 190 ° C. and a load of 2160 g, hereinafter referred to as MI) is not particularly limited, but is preferably 0.1 to 50 g / 10 min. EVOH may be modified with a small amount of a copolymerization monomer as long as the object of the present invention is not impaired.
The polysaccharide is a biopolymer synthesized in a living system by the condensation polymerization of various monosaccharides as described above, and includes those chemically modified based on them.

When the resin (B) used in the present invention is a high hydrogen bonding resin, a crosslinking agent can be used for the purpose of improving its water resistance (barrier properties after a water resistance environment test).
Preferable examples of the crosslinking agent include titanium coupling agents, silane coupling agents, melamine coupling agents, epoxy coupling agents, isocyanate coupling agents, copper compounds, zirconium compounds and the like. From the viewpoint of improving water resistance, a zirconium compound is particularly preferably used. Specific examples of the zirconium compound include, for example, zirconium halides such as zirconium oxychloride, hydroxyzirconium chloride, zirconium tetrachloride and zirconium bromide; zirconium salts of mineral acids such as zirconium sulfate, basic zirconium sulfate and zirconium nitrate; formic acid Zirconium salts of organic acids such as zirconium, zirconium acetate, zirconium propionate, zirconium caprylate, zirconium stearate; ammonium zirconium carbonate, sodium zirconium sulfate, ammonium zirconium acetate, sodium zirconium oxalate, sodium zirconium citrate, zirconium ammonium citrate, etc. And the like.
The addition amount of the cross-linking agent is not particularly limited, but the ratio (K = CN / HN) of the number of moles of cross-linking groups (CN) of the cross-linking agent to the number of moles of hydrogen bonding groups (HN) of the resin is 0. It is preferably used so as to be in the range of 001 to 10, and more preferably used so as to be in the range of 0.01 to 1.

<Gas barrier layer forming paint (C)>
As a method of laminating the gas barrier layer (II) containing the inorganic layered compound (A) and the resin (B) on the biaxially stretched film (I), the inorganic layered compound (A) and the resin (B) are used. The method of apply | coating the coating material (C) for gas barrier layer containing to the surface of a biaxially stretched film (I), and heat-processing is mentioned.

  The method for preparing the gas barrier layer-forming coating material (C) by blending the inorganic layered compound (A) and the resin (B) is not particularly limited. From the point of uniformity or ease of operation at the time of blending, for example, the dispersion obtained by previously swelling and cleaving the inorganic layered compound (A) and the liquid in which the resin (B) is dissolved are mixed, and then the solvent is removed. Method (Method 1), Method (Method 2) of removing the solvent by swelling and cleaving the dispersion of the inorganic layered compound (A) to the resin (B), and removing the solvent (Inorganic layered in the solution in which the resin (B) is dissolved) A method of removing a solvent (method 3) by adding a compound (A) and swelling and cleaving it, or a method of thermally kneading an inorganic layered compound (A) and a resin (B) (method 4) can be used. It is. From the viewpoint of easily obtaining a large aspect ratio of the inorganic layered compound (A), the former three are preferably used. In addition, the volume ratio of the inorganic layered compound (A) and the resin (B) in the gas barrier layer-forming coating material (C) is adjusted according to the volume ratio in the formed gas barrier layer (II).

  Examples of the dispersion medium for swelling and cleaving the inorganic layered compound (A) include water, alcohols (such as methanol, ethanol, propanol, isopropanol, ethylene glycol, and diethylene glycol), dimethylformamide, dimethyl sulfoxide, and acetone. In particular, water, alcohol, and a water-alcohol mixture are preferable.

  A known device such as a homogenizer can be used for mixing the inorganic layered compound (A) and the resin (B). From the viewpoint of dispersibility of the inorganic layered compound (A), it is preferable to perform high pressure dispersion treatment using a high pressure dispersion device.

  From the viewpoint of coating properties, the gas barrier layer-forming coating material (C) has a Zahn cup viscosity [Co., Ltd .: Zankup viscosity: No. 3)] is preferably adjusted to be in the range of 20 to 50S, and more preferably adjusted to be in the range of 25 to 45S. If it is less than 20S, the paint (C) may become undried depending on the length of the drying furnace. If it exceeds 50S, there is a problem in coating properties such as lowering the leveling properties of the liquid during coating. Prone to occur.

  In addition, the solid content concentration of the gas barrier layer-forming coating material (C) can be appropriately changed depending on the specifications of the coating apparatus, the drying and heating apparatus, but it is sufficient to exhibit gas barrier properties in an extremely dilute solution. It becomes difficult to apply a layer having a thickness, and a problem that a long time is required in the subsequent drying process tends to occur. On the other hand, when the concentration of the coating material (C) is too high, it is difficult to obtain a uniform coating material, which tends to cause problems in coating properties. From such a viewpoint, the solid content concentration of the paint (C) is preferably 4 to 8% by mass, and more preferably 5 to 7% by mass.

The gas barrier layer-forming coating material (C) prepared in the above methods 1 to 3 is obtained by using a direct gravure method, a reverse gravure method, a micro gravure method, a two-roll beat coat method, a bottom feed three-reverse coat method, etc. A roll coating method, a doctor knife method, a die coating method, a dip coating method, a bar coating method, a coating method combining these, and the like, a method of drying in an oven after applying to a biaxially stretched film (I), various dryers, etc. The gas barrier layer (II) can be formed by removing the solvent under the conditions of 30 to 260 ° C. and 0.5 to 60 minutes by the method using the dryer.
In addition, after removing the solvent from the system, heat aging is preferably performed at 110 to 220 ° C., so that water resistance (barrier properties after a water resistance environment test) can be improved. There is no limitation on the aging time, but it is necessary to reach a set temperature. For example, in the case of a method using a heat medium contact such as a hot air dryer, 1 second to 100 minutes is preferable. The heat source is not particularly limited, and various methods such as hot roll contact, heat medium contact (air, oil, etc.), infrared heating, microwave heating, and the like can be applied.

[Laminate adhesive layer (III)]
In the package of the present invention, the gas barrier layer (II) and the sealant layer (IV) laminated on the biaxially stretched film (I) are laminated via the laminate adhesive layer (III). .

  As the coating agent used when the laminated adhesive layer (III) is formed on the gas barrier layer (II), known coating agents are used. Examples of the coating agent include isocyanate, polyurethane, polyester, polyethyleneimine, polybutadiene, polyolefin, and alkyl titanate. Among these, in consideration of effects such as adhesion, heat resistance, and water resistance, an isocyanate-based, polyurethane-based, or polyester-based coating agent is preferable, and a mixture of one or more of isocyanate compounds, polyurethanes, and urethane prepolymers. And a reaction product, a mixture of one or more of polyester, polyol and polyether with isocyanate and a reaction product, or a solution or dispersion thereof.

  The method for applying the coating agent to the gas barrier layer (II) is not particularly limited, and usual methods such as gravure roll coating, reverse roll coating, wire bar coating, and air knife coating can be used. Although it does not specifically limit as a method of drying after application | coating, The method of using dryers, such as the method of drying in oven and various dryers, is mentioned, As drying conditions, 30-260 degreeC, 0.5-60 Minutes.

The thickness of the laminate adhesive layer (III) is preferably 0.05 to 10 g / m ² in terms of dry thickness in order to sufficiently improve the adhesion with the sealant layer (IV), and is preferably 0.1 to 5 g / m ^2. m ² is more preferable, and 0.5 to 3 g / m ² is even more preferable. Dry thickness or exceed 10 g / ^{m 2,} is less than 0.05 g / ^{m 2,} it is impossible to obtain sufficient adhesion.

[Sealant layer (IV)]
The sealant layer (IV) is provided as a heat bonding layer when forming a bag-shaped packaging bag or the like, and a material capable of heat sealing, high frequency sealing, or the like is used. For example, low density polyethylene (LDPE), linear low density polyethylene (LLDPE), high density polyethylene (HDPE), ethylene-vinyl acetate copolymer (EVA), polypropylene (PP), ethylene-acrylic acid copolymer (EAA) ), Ethylene-acrylate copolymer, ethylene-acrylate copolymer, and the like. The thickness is determined according to the purpose, but is generally 15 to 200 μm.

  As a method for laminating the sealant layer (IV) on the laminate adhesive layer (III), a known method is used. For example, lamination methods such as dry lamination method, wet lamination method, solvent-free dry lamination method, extrusion lamination method, co-extrusion method in which two or more resin layers are simultaneously extruded and laminated, coating method in which a film is formed with a coater, etc. However, the dry lamination method is preferable in view of adhesion, heat resistance, water resistance, and the like.

[Packaging]
The package of the present invention is a biaxially stretched film (I), a gas barrier layer (II), a laminate adhesive layer (III), and a sealant layer (IV) laminated in this order. It has a layer structure of (I) (II) (III) (IV) and a layer structure of (I) (II) (II) (III) (IV). Further, in some cases, a functional layer such as a primer layer or an antistatic layer may be laminated between the gas barrier layer (II) and the laminate adhesive layer (III). In addition, the gas barrier layer (II) and the laminate adhesive layer (III) may be subjected to surface treatment such as corona treatment or ozone treatment in order to improve the adhesion between them. Furthermore, printing can be performed by a known method as necessary on the gas barrier layer (II) surface or the biaxially stretched film (I) surface on which the gas barrier layer (II) or the like is not laminated.

  The package of the present invention is particularly suitable for the food field because it can be applied to various fields that require oxygen barrier properties and laminate strength and is excellent in straight-cut properties.

  EXAMPLES The present invention will be specifically described below with reference to examples and comparative examples, but the present invention is not limited to only these examples.

The physical property measurement method and evaluation method are described below.
[Thickness measurement]
The thickness of 0.5 μm or more was measured with a commercially available digital thickness gauge (contact thickness gauge, trade name: ultra-high precision deci-micro head MH-15M, manufactured by Nippon Optical Co., Ltd.). On the other hand, the thickness of less than 0.5 μm was determined by gravimetric analysis (the weight measured value of a certain area of film was divided by the area and further divided by the specific gravity of the composition).

[Particle size of inorganic layered compound]
Using a laser diffraction / scattering particle size distribution analyzer (LA910, manufactured by Horiba, Ltd.), the volume standard of particles considered to be inorganic layered compounds in gas barrier layer forming coating solution C-1 containing polyvinyl alcohol and inorganic layered compounds The median diameter was measured with a flow cell method at an optical path length of 4 mm.

[Aspect ratio of inorganic layered compound]
Using an X-ray diffractometer (manufactured by Shimadzu Corporation, XD-5A), diffraction measurement by powder method for an inorganic layered compound alone and a dried gas barrier layer forming coating solution containing polyvinyl alcohol and an inorganic layered compound The unit thickness a of the inorganic layered compound was determined. Using the particle diameter L obtained by the above method, the aspect ratio Z was calculated by the equation Z = L / a. In addition, from the diffraction measurement about what dried the coating liquid for gas barrier layer formation, it confirmed that there existed the part which the surface interval of an inorganic layered compound has spread.

[Oxygen barrier properties]
A biaxially stretched film (I) and a gas barrier layer in an atmosphere of a temperature of 20 ° C. and a relative humidity of 65% based on JIS K7126-2 method using an oxygen barrier measuring device (OX-TRAN 2 / 20MH) manufactured by Mocon The oxygen permeability of the laminate containing (II) was measured.

[Strong laminate]
A test piece having a length of 100 mm and a width of 15 mm was prepared from the obtained package in an atmosphere of a temperature of 23 ° C. and a relative humidity of 50%, and the gap between the biaxially stretched film (I) and the sealant layer (IV) was prepared. A non-adhesive part is prepared by peeling a length of 30 mm or more in the MD direction with tweezers, and the non-adhesive part is used as a grip, and a tensile tester (Autograph AG-1S manufactured by Shimadzu Corporation) is used to obtain 300 mm / The average peel strength when a T-type peel of 50 mm length in the MD direction at a min peel rate was measured for 5 samples, and the average value was defined as the laminate strength.

[Straight line evaluation]
From the obtained package, a three-sided side bag with an MD direction of 200 mm, a TD direction of 300 mm, and a seal width of 10 mm was produced. A 5mm cut (notch) is provided in the seal part in the TD direction, and the width of the package on the front and back sides of the three-side bag is measured when the three-side bag is torn in the right and left front directions in the MD direction. did. This operation was repeated 5 times, and the average value of the deviation widths was calculated, and when the right and left front deviation widths were less than 2 mm, the case of ◯ and 2 mm or more was marked as x.

[Evaluation of delamination on opening]
In the straight-cut property evaluation using a three-sided bag produced from a package, the presence or absence of delamination at the time of opening was evaluated. The case where delamination did not occur at the time of opening was evaluated as ◯, and the case where delamination occurred was evaluated as x.

The materials used for the production of the package are as follows.
[Biaxially stretched polyamide film]
Using a raw material in which nylon 6 and MXD6 are mixed at a ratio of nylon 6 / MXD6 = 85/15, 80/20, 95/5, 97/3, 75/25 or 100/0 (mass ratio), the resin temperature After extruding at 260 ° C., closely adhering to a cooling drum at 15 ° C., and simultaneously biaxially stretching 3 × 3.3 times in the longitudinal and transverse directions at a stretching temperature of 185 ° C. with a tenter simultaneous biaxial stretching machine, A biaxially stretched polyamide film having a thickness of 15 μm produced by heat treatment at 4 ° C. for 4 seconds was used.

[Biaxially stretched polyester film]
Extruded at a resin temperature of 280 ° C. using raw materials in which PET and modified PBT are mixed at a ratio of PET / modified PBT = 87/13, 70/30, 95/5, 60/40 or 100/0 (mass ratio). , The film was closely cooled to a cooling drum at 20 ° C., stretched 3.5 times at 90 ° C. with a roll longitudinal stretching machine and 4.5 times at 120 ° C. with a tenter transverse stretching machine, and then heat treated at 235 ° C. for 4 seconds. The produced biaxially stretched polyester film with a thickness of 12 μm was used.

[Anchor coating agent]
Toyo Morton EL-510-1-17K, CAT-87RT (EL-510-1-17K / CAT-87RT = 5/1 (mass ratio)) and solvent (toluene / MEK / MIBK = 5/4 / 1 (mass ratio)) and an anchor coating agent adjusted to a concentration of 4% by mass was used.

[Gas barrier layer forming paint (C)]
[Coating fluid C-1]
Ion-exchanged water (0.7 μS / cm or less) and polyvinyl alcohol (PVA-117H manufactured by Kuraray Co., Ltd., saponification degree 99.6%, polymerization degree 1700) are charged into the dispersion kettle, and low-speed stirring (800 rpm, peripheral The temperature was raised to 95 ° C. under a speed of 2 m / min) and stirred for 30 minutes at the same temperature to dissolve the polyvinyl alcohol, and then cooled to 60 ° C. to obtain a 9.0 mass% polyvinyl alcohol aqueous solution. To this polyvinyl alcohol aqueous solution, an alcohol aqueous solution in which ion exchange water and 2-propanol are mixed (ion exchange water / 2-propanol = 4/1 (mass ratio)) is added over 10 minutes, and high speed stirring (1600 rpm, peripheral speed) is added. 4 m / min) and stirred for 20 minutes to obtain a 6% by mass aqueous polyvinyl alcohol solution.
To the obtained aqueous polyvinyl alcohol solution, an inorganic layered compound (montmorillonite, Kunipia RG manufactured by Kunimine Industries Co., Ltd.) was gradually added, and after completion of addition, high-speed stirring (1600 rpm, peripheral speed 4 m / min) was continued at 60 ° C. for 60 minutes. Thereafter, 2-propanol was further added over 10 minutes, and the mixture was cooled to room temperature to obtain a C-1 preparation solution.
0.1 parts by mass of a nonionic surfactant (SH3746 manufactured by Toray Dow Corning Co., Ltd.) is added to 0.01 parts by mass of this preparation liquid, and a high-pressure dispersion apparatus (ultra-high pressure homogenizer manufactured by Microfluidizer) is used. And 1000 kgf / cm ² . Subsequently, an alcohol aqueous solution (ion-exchanged water / 2-propanol = 1 / 1.2 (mass ratio)) in which ion-exchanged water and 2-propanol are mixed so that the final solid content concentration is 5.8% by mass is 10. The mixture was added over a period of 20 minutes and stirred at a high speed for 20 minutes (1600 rpm, peripheral speed 4 m / min) to obtain a coating liquid C-1.
In the obtained coating liquid C-1, the volume ratio of the inorganic layered compound to the resin (inorganic layered compound / resin) is 5/95. The average particle diameter of the cleaved inorganic layered compound (montmorillonite) was 560 nm, the unit thickness obtained from powder X-ray diffraction, that is, the a value was 1.2156 nm, and the aspect ratio was 460.

[Coating fluid C-2]
The amount of inorganic layered compound added is changed so that the volume ratio (inorganic layered compound / resin) becomes 3/97, and the amount of alcohol aqueous solution added is changed so that the final solid content concentration becomes 6% by mass. A coating solution C-2 was produced in the same manner as in the coating solution C-1 except for the above.

[Coating fluid C-3]
The addition amount of the inorganic stratiform compound is changed so that the volume ratio (inorganic stratiform compound / resin) is 7/93, and the addition amount of the alcohol aqueous solution is changed so that the final solid content concentration is 5.6% by mass. A coating solution C-3 was prepared in the same manner as the coating solution C-1 except that the coating solution C-1 was prepared.

[Coating fluid C-4]
The addition amount of the inorganic stratiform compound is changed so that the volume ratio (inorganic stratiform compound / resin) is 10/90, and the addition amount of the alcohol aqueous solution is changed so that the final solid content concentration is 5.4% by mass. A coating solution C-4 was prepared in the same manner as the coating solution C-1 except that the coating solution C-1 was prepared.

[Coating fluid C-5]
The addition amount of the inorganic layered compound is changed so that the volume ratio (inorganic layered compound / resin) is 20/80, and the addition amount of the aqueous alcohol solution is changed so that the final solid content concentration is 4.9% by mass. A coating solution C-5 was prepared in the same manner as the coating solution C-1 except that the coating solution C-1 was prepared.

[Coating fluid C-6]
The addition amount of the inorganic stratiform compound is changed so that the volume ratio (inorganic stratiform compound / resin) becomes 2/98, and the addition amount of the alcohol aqueous solution is changed so that the final solid content concentration is 6.2% by mass. A coating solution C-6 was produced in the same manner as the coating solution C-1 except that the coating solution C-1 was prepared.

Example 1
As biaxially stretched film (I), nylon 6 / MXD6 is 85/15 (mass ratio), single-sided corona-treated biaxially stretched polyamide film is used, anchor coat agent is used on the treated surface, and bar coater No. 3 is used. And then dried with a hot air dryer at 80 ° C. for 1 minute to form an anchor coat layer. The dry thickness of this anchor coat layer was 0.07 μm.
On the anchor coat layer, a gas barrier layer forming coating (coating liquid C-1) is gravure coated (test coater manufactured by Hirano Techseed Co., Ltd., micro gravure coating method, coating speed 5 m / min, drying temperature 80 ° C.). A gas barrier layer (II) was obtained. The film thickness (dry thickness) of the gas barrier layer (II) was 0.3 μm. Table 1 shows the results of measuring the oxygen permeability of the obtained laminate including the biaxially stretched film (I) and the gas barrier layer (II).
Next, a coating agent for forming a laminate adhesive layer (III) (TM-329 / CAT-8B manufactured by Toyo Morton Co., Ltd.) was applied onto the gas barrier laminate (II) so that the dry film thickness was 2 g / m ^2. Then, it was dried for 10 seconds with a hot air dryer at 80 ° C. to form a laminate adhesive layer (III).
A film for sealant layer (IV) (LLDPE-40 μm TUX-FCS corona surface side manufactured by Mitsui Chemicals, Inc.) was bonded to the formed laminate adhesive layer (III) surface by a nip roll (nip condition 80 ° C.). The laminate was cured at 40 ° C. for 3 days to cure the laminate adhesive layer (III), thereby obtaining a package body laminated in the order of (I) (II) (III) (IV).
Table 1 shows the measurement results of the laminate strength of the obtained package, and the evaluation results of the straight cut property and the occurrence of delamination at the time of opening.

Examples 2-3
Example 1 except that the gas barrier layer-forming coating material was changed to coating solution C-2 (Example 2) and coating solution C-3 (Example 3), and the thickness of the gas barrier layer (II) was changed. In the same manner, a laminate and a package were obtained.

Examples 4-5
Biaxially stretched film (I) is a biaxially stretched polyamide film (Example 4) in which nylon 6 / MXD6 is 80/20 (mass ratio), and biaxially stretched polyamide film (implemented in 95/5 (mass ratio)). Except having changed to Example 5), it carried out similarly to Example 1, and obtained the laminated body and the package.

Example 6
A laminate and a package were obtained in the same manner as in Example 1 except that the biaxially stretched film (I) was changed to a biaxially stretched polyester film having a PET / modified PBT of 87/13.

Examples 7-8
Example 6 except that the gas barrier layer-forming coating material was changed to coating liquid C-2 (Example 7) and coating liquid C-3 (Example 8), and the thickness of the gas barrier layer (II) was changed. In the same manner, a laminate and a package were obtained.

Examples 9-10
Biaxially stretched film (I), biaxially stretched polyester film (Example 9) with PET / modified PBT of 70/30 (mass ratio), biaxially stretched polyester film with 95/5 (mass ratio) Except having changed into Example 10), it carried out similarly to Example 6, and obtained the laminated body and the package.

Comparative Examples 1-2
Biaxially stretched film (I), biaxially stretched polyester film having a PET / modified PBT of 60/40 (mass ratio) (Comparative Example 1) and 100/0 (mass ratio) (comparative) A laminate and a package were obtained in the same manner as in Example 6 except for changing to Example 2).

Comparative Examples 3-4
Biaxially stretched film (I) is a biaxially stretched polyamide film (comparative example 3) in which nylon 6 / MXD6 is 97/3 (mass ratio), biaxially stretched polyamide film (comparative) Except having changed to Example 4), it carried out similarly to Example 1, and obtained the laminated body and the package.

Comparative Examples 5-7
The gas barrier layer-forming coating material was changed to coating liquid C-4 (Comparative Example 5), coating liquid C-5 (Comparative Example 6), and coating liquid C-6 (Comparative Example 7). A laminate and a package were obtained in the same manner as in Example 1 except that the thickness of II) was changed.

Comparative Example 8
As a biaxially stretched film (I), an attempt was made to produce a biaxially stretched polyamide film using a raw material in which nylon 6 / MXD6 was mixed at a ratio of 75/25 (mass ratio). Since it was difficult to adjust the thickness, the film could not be collected.

  Table 1 shows the results of measuring the oxygen permeability of the laminates obtained in the Examples and Comparative Examples, the measurement results of the laminate strength of the package, and the evaluation results of the linear cut property and the occurrence of delamination at the time of opening.

In Examples 1 to 10, the gas barrier layer had an excellent oxygen barrier property, and the package had excellent linear cut properties and laminate strength, and no delamination occurred during opening.
Although Comparative Examples 1 and 2 have excellent laminate strength and oxygen barrier properties, the content of the modified PBT constituting the biaxially stretched film (I) exceeds the range specified in the present invention, and thus linear cut properties are obtained. I couldn't.
Comparative Examples 3 and 4 have excellent laminate strength and oxygen barrier properties, but the content of MXD6 constituting the biaxially stretched film (I) is less than the amount specified in the present invention, so that linear cut properties are obtained. I could not.
Comparative Examples 5 to 6 have excellent oxygen barrier properties and linear cut properties, but the volume ratio in the gas barrier layer (II) [inorganic layered compound (A) / resin (B)] is outside the range specified in the present invention. As a result, the laminate strength decreased, and delamination occurred during opening.
Since Comparative Example 7 has excellent linear cut property and laminate strength, the volume ratio [inorganic layered compound (A) / resin (B)] in the gas barrier layer (II) is outside the range specified in the present invention. Sufficient oxygen barrier property was not obtained.
In Comparative Example 8, since the content of MXD6 in the resin constituting the biaxially stretched polyamide film was larger than the amount specified in the present invention, the biaxially stretched polyamide film itself could not be collected and was not evaluated.

Claims (7)

  A package in which a biaxially stretched film (I) having a linear cut property in the longitudinal direction of the film, a gas barrier layer (II), a laminate adhesive layer (III), and a sealant layer (IV) are laminated in this order. The biaxially stretched film (I) contains nylon 6 and poly (metaxylylene adipamide), and their mass ratio [nylon 6 / poly (metaxylylene adipamide)] is 80/20. The biaxially stretched film (I) contains polyethylene terephthalate (PET) and modified polybutylene terephthalate (modified PBT), and the mass ratio [PET / modified PBT] is Polybutylene terephthalate which is 70/30 to 95/5 and whose modified PBT contains 5 to 20% by mass of a polytetramethylene glycol unit having a molecular weight of 600 to 4000 The gas barrier layer (II) contains the inorganic layered compound (A) and the resin (B), and the volume ratio [inorganic layered compound (A) / resin (B)] is 3/97 to A linear-cutting gas barrier package characterized by being 7/93. In the laminate including the biaxially stretched film (I) and the gas barrier layer (II), the oxygen permeability converted per 1 μm thickness of the gas barrier layer (II) is 2 ml / m ² at 20 ° C. and 65% RH. The linear-cutting gas barrier package according to claim 1, which is not more than day · MPa.   The linear barrier gas barrier package according to claim 1 or 2, wherein the gas barrier layer (II) has a thickness of 0.1 to 1 µm.   4. The linear cut gas barrier package according to any one of claims 1 to 3, wherein the laminate has a laminate strength of 3.5 N / cm or more.   The linear cut gas barrier package according to any one of claims 1 to 4, wherein the inorganic layered compound (A) has an average particle size of 5 µm or less and an aspect ratio of 50 to 5,000.   Resin (B) is high hydrogen bond resin, The linear cut gas barrier package in any one of Claims 1-5 characterized by the above-mentioned. 7. The straight-cut gas barrier package according to claim 6, wherein the high hydrogen bonding resin is polyvinyl alcohol.