JPH07251874A - Bag for retprt pack - Google Patents

Abstract

PURPOSE:To provide high gas-barriering capacity and to provide recovery properties of oxygen gas-barriering after retort sterilization. CONSTITUTION:In a laminated material composed of an external layer A 1, an internal layer B 3 and an intermediate layer C 2, the intermediate layer C 2 is made of a composition composed of an inorganic lamellar compound in particle size of 5mum or below and aspect ratio of 50 to 5000 and a high hydrogen-bonding resin. Water vapor permeability ratio A/B of the layer A 1 to the layer B 3 is set as 2 or above.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a retort packaging bag having excellent gas barrier properties and oxygen barrier recovery properties after retort sterilization.

[0002]

BACKGROUND OF THE INVENTION Although various functions are required for packaging, various gas barrier properties for protecting contents are important properties that affect the storability of foods. Distribution forms, diversification of packaging technology, regulation of additives However, due to changes in tastes and the like, the need for it is increasing.

The resin can be formed into a film and processed into a bag because of its easy moldability. Resin packaging bags are being largely replaced with conventional packaging containers such as metal cans, glass bottles, and ceramics because of their advantages such as light weight, flexibility, and transparency of contents. On the other hand, the weak point of the resinous packaging bag is that it has a low barrier property against oxygen, water, and low-molecular-weight substances contained in the contents, which are weaknesses of alteration of the contents.

As a resin material, improvement of gas barrier property has been studied, and a packaging bag in which a transparent plastic material having a small gas barrier property is compounded is known.
A packaging bag having at least one layer made of polyvinyl alcohol, a polyethylene vinyl alcohol copolymer, a polyvinylidene chloride resin, etc. is known. However, the packaging bags obtained by these techniques are not yet satisfactory in gas barrier properties, and it cannot be said that they are necessarily satisfactory for protecting the contents.

Further, due to recent changes in eating habits, the demand for retort foods such as curry is rapidly expanding. However, since this retort pouch food is subjected to high temperature and high pressure sterilization, water entering the barrier layer at that time remarkably deteriorates the oxygen barrier property, which causes problems such as delay in recovery of the barrier property and peeling (derami) of the outer layer. Particularly, in the ethylene-vinyl alcohol copolymer-based barrier film, the problem of temporary deterioration of the oxygen barrier property is remarkable, and EV water due to invading water is also a problem.
The cloudiness of the OH layer is another problem. Film delamination has become a problem in the polyvinylidene chloride system.

[0006]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a retort packaging bag having a high level of oxygen gas barrier property and excellent oxygen barrier property after retort sterilization. .

[0007]

Means for Solving the Problems As a result of intensive studies for solving the above problems, the present inventors have found that in a mixed composition comprising an inorganic layered compound of an intermediate layer C and a high hydrogen bonding resin, the inorganic layered compound It was found that remarkably excellent gas barrier properties are exhibited by making the aspect ratio extremely large, and as a result of further studies, the mixed composition was used as the intermediate layer C, and the moisture permeability ratio of the outer layer A and the inner layer B was increased. A / B
It was found that the oxygen barrier property after retort sterilization was excellent when the value was 2 or more, and the present invention was accomplished.

That is, the present invention comprises an outer layer A, an inner layer B, and an intermediate layer C, and the C layer is a composition comprising an inorganic layered compound having a particle size of 5 μm or less and an aspect ratio of 50 to 5000 and a high hydrogen-bonding resin. Consists of layers A and B
The present invention relates to a retort packaging bag, wherein the layer has a moisture permeability ratio A / B of 2 or more.

The inorganic layered compound used in the present invention is
An inorganic compound in which unit crystal layers are stacked on each other to have a layered structure. In other words, "layered compound" means
A compound or substance having a layered structure, and a "layered structure" is a structure in which atoms are strongly bonded by covalent bonds or the like and the densely arranged faces are stacked in parallel by weak bonding forces such as van der Waals forces. Say. The “inorganic layered compound” that can be used in the present invention has an aspect ratio of 50 or more and 5000 or less and a particle size of 5 μm as measured by the method described below.
The following are not particularly limited. From the viewpoint of gas barrier properties, the aspect ratio is preferably 100 or more (particularly 200 or more). When the aspect ratio is less than 50, the gas barrier property is insufficiently expressed. On the other hand, it is technically difficult to obtain an inorganic layered compound having an aspect ratio of more than 5,000, and it is expensive in terms of cost or economy. From the viewpoint of ease of manufacturing, the aspect ratio is preferably 2000 or less (further 1500 or less). From the viewpoint of the balance between gas barrier properties and easiness of production, the aspect ratio is more preferably in the range of 200 to 3000. From the viewpoint of film formability or moldability when formed into a film, the “particle size” measured by the method described below is preferably 5 μm or less. If the particle size exceeds 5 μm, the film-forming property or moldability of the resin composition tends to deteriorate. From the viewpoint of transparency of the resin composition, the particle size is preferably 3 μm or less. When the film of the present invention is used for applications where transparency is important (for example, food applications), it is particularly preferable that the particle size is 1 μm or less. Also, this transparency is
The total light transmittance at a wavelength of 500 nm is preferably about 80% or more (more preferably 85% or more). Such transparency can be suitably measured with, for example, a commercially available spectrophotometer (manufactured by Hitachi, Ltd., self-recording spectrophotometer Model 330). Specific examples of the inorganic layered compound include graphite, phosphate-based derivative-type compounds (zirconium phosphate-based compounds), chalcogenides [Group IV (Ti, Zr,
Hf), group V (V, Nb, Ta) and group VI (Mo,
W) is a dichalcogenide and is represented by the formula MX ₂ . Here, X represents chalcogen (S, Se, Te). ], Clay-based minerals and the like can be mentioned. The inorganic layered compound of the intermediate layer C used in the present invention is an inorganic compound in which unit crystal layers are stacked on each other to have a layered structure, and has a particle size of 5 μm or less and an aspect ratio of 50 or more and 5000 or less. Then, it is not particularly limited. Regarding gas barrier properties, the aspect ratio is 200-300
The range of 0 is more preferable. If the aspect ratio is less than 50, the gas barrier property is not sufficiently exhibited, and if it is more than 5000, it is technically difficult and economically expensive. Further, when the particle size is 3 μm or less, the transparency is better, and when the particle size is 1 μm or less, the transparency is more preferable for applications where importance is attached to the transparency. Specific examples of the inorganic layered compound include graphite, phosphate-based derivative type compounds (zirconium phosphate-based compounds), chalcogenides [I
It is a dichalcogenide of group V (Ti, Zr, Hf), group V (V, Nb, Ta) and group VI (Mo, W), and is represented by the formula MX2. Where X is chalcogen (S, S
e, Te). ], Clay-based minerals and the like can be mentioned.

The particle size of the inorganic layered compound used in the present invention means the particle size determined by the dynamic light scattering method in a solvent.
It is extremely difficult to measure the true particle size in the resin composition, but when the resin is swelled sufficiently with the same solvent as the solvent used in the dynamic light scattering method to form a composite with the resin, the inorganic layered compound in the resin is used. The particle size of can be considered to be close to the particle size in the solvent.

The aspect ratio (Z) of the inorganic layered compound used in the present invention is represented by the relationship Z = L / a.
[L is a particle size obtained by a dynamic light scattering method in a solvent, and a is a unit thickness of the inorganic layered compound (unit thickness a is a measurement of the inorganic layered compound alone by a powder X-ray diffraction method or the like. It is a value determined by.)]. However, Z = L / a
, The interplanar spacing d obtained from powder X-ray diffraction of the composition
Exists and satisfies the relationship of a <d. Here, it is necessary that the value of da is larger than the width of the resin single chain in the composition. Z cannot necessarily be said to be the true aspect ratio of the inorganic layered compound in the resin composition, but is considerably appropriate for the following reasons.

Direct measurement of the aspect ratio of the inorganic layered compound in the resin composition is extremely difficult. Composition powder X
Between the interplanar spacing d obtained by the line diffraction method and the unit thickness a determined by the powder X-ray diffraction measurement of the inorganic layered compound alone, a <d
If the value of da is equal to or more than the width of the resin single chain in the composition, it means that the resin is inserted between the layers of the inorganic layered compound in the resin composition. It is clear that the thickness of the layered compound is the unit thickness a. In addition, it is extremely difficult to measure the true particle size in the resin composition, but in the case of swelling sufficiently with a solvent of the same kind as the solvent used in the dynamic light scattering method to form a composite with the resin, It can be considered that the particle size of the inorganic layered compound in is very close to that in the solvent (however, the particle size L determined by the dynamic light scattering method is the major axis Lma of the inorganic layered compound).
Since it is considered that x does not exceed x, the true aspect ratio Lmax / a cannot theoretically fall below the definition Z of the aspect ratio in the present invention. ). From the above two points, the definition of the aspect ratio of the present invention is considered to be relatively valid. In the present invention, the aspect ratio or particle size means the aspect ratio and particle size defined above. For details of how to obtain a and d, refer to, for example, Shu Iwao et al., Encyclopedia of Clay, pages 35 and below and pages 271 and below, 1985, Asakura Shoten Co., Ltd. 3-9). Further, the width of the resin single chain in the composition can be obtained by simulation calculation or the like (for example, Okamura et al.
(Introduction to Polymer Chemistry, pp. 103-110, 1981, Kagaku Dojin), in the case of polyvinyl alcohol 4 ~
It is 5 angstroms (2 to 3 angstroms for water molecules). Thus, the integrated intensity of the diffraction peak (corresponding to the interplanar spacing d) observed in the powder X-ray diffraction of the resin composition is 2 or more in a relative ratio to the integral intensity of the reference diffraction peak (corresponding to the interplanar spacing a). (More preferably 10 or more) is preferable. FIG. 3 is a graph schematically showing the relationship between the X-ray diffraction peak of the inorganic layered compound and the unit thickness a of the compound. FIG. 4 is a graph schematically showing the relationship between the X-ray diffraction peak of a resin composition containing an inorganic layered compound and the plane spacing d of the composition. FIG. 5 shows the relationship between the X-ray diffraction peak of the resin composition and the interplanar spacing d of the composition when the peak corresponding to the interplanar spacing d overlaps with the halo (or background) and is difficult to detect. It is a graph which shows typically. In this figure, the area of the portion excluding the base line on the lower angle side than 2θd is the peak corresponding to the surface spacing d (θd is the “unit thickness a +
The diffraction angle corresponds to the "width of the resin single chain"). Figure 6
3 is a graph showing an X-ray diffraction peak of a polyvinyl alcohol PVA117H / Kunipia F composition and a graph showing an X-ray diffraction peak of Kunipia F (montmorillonite). FIG. 7 is a graph showing the X-ray diffraction peaks (pattern of FIG. 4) of the composition with the interplanar spacing d = 19.62 angstroms. FIG. 8 is a graph showing the X-ray diffraction peaks (patterns in FIGS. 4 and 5) of the composition with the interplanar spacing d = 32.94 Å. In FIG. 9, the surface spacing d is 44.
It is a graph which shows the X-ray-diffraction peak (pattern of FIG. 5) of a composition of 13 angstroms or more.

As the inorganic layered compound having a large aspect ratio, an inorganic layered compound which swells and cleaves in a solvent is preferably used. The degree of "swelling / cleavage" of the inorganic layered compound used in the present invention in a solvent is as follows.
It can be evaluated by the "cleavage" test. The swelling property of the inorganic layered compound is preferably about 5 or more (more preferably about 20 or more) in the following swelling test.
On the other hand, the cleavage property of the inorganic layered compound is preferably about 5 or more (more preferably about 20 or more) in the following cleavage property test. In these cases, a solvent having a density lower than that of the inorganic layered compound is used as the solvent. When the inorganic layered compound is a natural swelling clay mineral, it is preferable to use water as the solvent. <Swelling test>: Inorganic layered compound 2 g, solvent 100 mL
Slowly add to the container (contain a 100 mL graduated cylinder). After shaking and standing, the volume of the former (inorganic layered compound dispersed layer) is read from the scale of the interface between the inorganic layered compound dispersed layer and the supernatant after 24 hours at 23 ° C. The larger this value, the higher the swelling property. <Cleavability test>: 30 g of the inorganic layered compound is used as the solvent 150
Add slowly to 0 mL, disperser (manufactured by Asada Tekko KK, Despar MH-L, blade diameter 52 mm, rotation speed 3100 rp)
m, container volume 3 L, bottom-blade distance 28 mm), and dispersed at a peripheral speed of 8.5 m / sec for 90 minutes (23
℃), take 100 mL of the dispersion liquid, put it in a 100 mL graduated cylinder and let stand for 60 minutes, then read the volume of the inorganic layered compound dispersion layer from the scale of the interface with the supernatant. The larger this value, the higher the cleavability. As the inorganic layered compound that swells and cleaves in a solvent, a clay mineral that has a swelling and cleaving property in a solvent can be preferably used. Clay-based minerals are generally
A type having a two-layer structure having an octahedron layer having a central metal such as aluminum or magnesium on a tetrahedral layer of silica, and a tetrahedral layer of silica having an octahedron layer having a central metal such as aluminum or magnesium. It is classified as a type consisting of a three-layer structure in which is sandwiched from both sides. Examples of the former include kaolinites and antigorites, and examples of the latter include smectites, vermiculites and mica depending on the number of interlayer cations. Specifically, kaolinite, dickite,
Nacrite, halloysite, antigorite, chrysotile, pyrophyllite, montmorillonite, hectorite, tetrasilylic mica, sodium teniolite, muscovite, margarite, talc, vermiculite, phlogopite, xanthophyllite, chlorite, etc. be able to.

The solvent for swelling the inorganic layered compound is
For example, in the case of a natural swelling clay mineral, water, alcohols such as methanol, ethanol, propanol, isopropanol, ethylene glycol, diethylene glycol, dimethylformamide, dimethylsulfoxide, acetone and the like can be used, but not limited to water and water. Alcohols such as methanol are more preferred.

The highly hydrogen-bonding resin used in the present invention is one having a weight percentage of hydrogen-bonding groups or ionic groups per unit weight of resin of 20% to 60%. A more preferable example is one in which the weight percentage of hydrogen-bonding groups or ionic groups per unit weight of the resin of the high hydrogen-bonding resin satisfies the ratio of 30% to 50%. Among the hydrogen-bonding groups or ionic groups of the high hydrogen-bonding resin, more preferable ones are a hydroxyl group, an amino group, a thiol group, a carboxyl group, a sulfonic acid group,
A phosphoric acid group, etc., a carboxylate group as the ionic group,
Sulfonate ion group, phosphate ion group, ammonium group,
Examples include phosphonium groups. Specific examples include, for example, polyvinyl alcohol and vinyl alcohol having a fraction of 4
1 mol% or more of ethylene-vinyl alcohol copolymer,
Polysaccharides such as hydroxymethyl cellulose, hydroxyethyl cellulose, carboxymethyl cellulose, amylose, amylopectin, pullulan, curdlan, xanthan, chitin, chitosan, cellulose, pullulan, chitosan, polyacrylic acid, sodium polyacrylate, polybenzenesulfonic acid, Examples thereof include sodium polybenzenesulfonate, polyethyleneimine, polyallylamine, ammonium thiols thereof, polyvinylthiol, polyglycerin, and the like.

Further preferable examples of the high hydrogen bond resin include polyvinyl alcohol and polysaccharides.
The polyvinyl alcohol used in the layer containing the inorganic layered compound of the present invention is a polymer having a monomer unit of vinyl alcohol as a main component. Examples of such "polyvinyl alcohol" include, for example, a polymer obtained by hydrolyzing or transesterifying (saponifying) the acetic ester portion of a vinyl acetate polymer (precisely, it is a copolymer of vinyl alcohol and vinyl acetate). And a polymer obtained by saponifying a trifluorovinyl acetate polymer, a vinyl formate polymer, a vinyl pivalate polymer, a t-butyl vinyl ether polymer, a trimethylsilyl vinyl ether polymer (“polyvinyl alcohol”).
For more details, refer to, for example, "The World of PVA", edited by Poval Society, 1992, Polymer Publishing Co., Ltd .; Nagano et al., Poval, 1981, Polymer Publishing Co., Ltd.) . The degree of "saponification" in polyvinyl alcohol is preferably 70% or more in terms of molar percentage, and 85
% Or more, more preferably 98% or more, a so-called completely saponified product. The degree of polymerization is 100.
It is preferably 5,000 or more and 5,000 or less, more preferably 200 or more and 3,000 or less.

The term "polysaccharide" as used herein refers to a biopolymer synthesized in a biological system by polycondensation of various monosaccharides, and includes those chemically modified based on these. For example, cellulose and cellulose derivatives such as hydroxymethyl cellulose, hydroxyethyl cellulose, carboxymethyl cellulose, amylose, amylopectin, pullulan, curdlan, xanthan, chitin,
Examples include chitosan.

In the C layer used in the present invention, a hydrogen bonding group-crosslinking agent can be used for the purpose of improving its water resistance (meaning the barrier property after a water resistance environment test).

The crosslinking agent for hydrogen-bonding group is not particularly limited, but examples thereof include titanium coupling agents, silane coupling agents, melamine coupling agents, epoxy coupling agents, isocyanate coupling agents,
A copper compound, a zirconia compound, etc. are mentioned, More preferably, a zirconia compound is mentioned.

Specific examples of the zirconia compound include zirconium oxychloride, zirconium hydroxychloride, zirconium tetrachloride, zirconium halides such as zirconium bromide, zirconium sulfate, basic zirconium sulfate, zirconium nitrate and other mineral acids. Zirconium salts of organic acids such as salts, zirconium formate, zirconium acetate, zirconium propionate, zirconium caprylate, zirconium stearate, ammonium zirconium carbonate, sodium zirconium sulfate, ammonium zirconium acetate, sodium zirconium oxalate, sodium zirconium citrate, citric acid Zirconium complex salts such as zirconium ammonium,
And so on.

The amount of the cross-linking agent for hydrogen-bonding groups added is the ratio (K) of the number of moles (CN) of cross-linking groups of the cross-linking agent to the number of moles (HN) of hydrogen-bonding groups of the high hydrogen-bonding resin. That is, K = C
N / HN] is not particularly limited as long as it is in the range of 0.001 or more and 10 or less, but is preferably in the range of 0.01 or more and 1 or less.

The composition ratio (volume ratio) of the inorganic layered compound and the resin of the intermediate layer C used in the present invention is not particularly limited, but generally, the volume ratio of (inorganic layered compound / resin) is 5 / 95-90 / 10 range, volume ratio 5 / 95-50 / 5
The range of 0 is more preferable. In addition, when the volume ratio of (inorganic layered compound / resin) is in the range of 5/95 to 30/70, the flexibility of the film is good, and in the range of 7/93 to 17/83, the deterioration of the barrier property due to bending is small. In addition, the peel strength is increased. Further, when the volume fraction of the inorganic layered compound is smaller than 5/95, the barrier performance is not sufficient,
If it is larger than 90/10, the film forming property is not good.

The method of blending the composition comprising the inorganic layered compound and the resin is not particularly limited, but, for example, a solution in which the resin is dissolved and a dispersion in which the inorganic layered compound is swollen and cleaved in advance are mixed with a solvent. Method of removing, a method of adding a dispersion liquid obtained by swelling and cleaving an inorganic layered compound to a resin to remove the solvent, a method of adding an inorganic layered compound to a solution in which a resin is dissolved, and making a dispersion liquid of the swollen and cleaved, and removing a solvent Moreover, the method of heat-kneading a resin and an inorganic layered compound, etc. are mentioned. In particular, the former three methods are preferably used as a method for easily obtaining a large aspect ratio.

In the above-mentioned three methods, the solvent is removed from the system and then heat-aged at 110 ° C. or higher and 220 ° C. or lower to improve the water resistance of the film (meaning the barrier property after the water resistance environment test). To do. Although the aging time is not limited, it is necessary that the film reaches at least the set temperature, and in the case of a method using a heating medium contact such as a hot air dryer, it is preferably 1 second or more and 100 minutes or less. The heat source is also not particularly limited, and includes heat roll contact, heat medium contact (air, oil, etc.), infrared heating, microwave heating,
Various other types can be applied. Further, the water resistance effect here is remarkably high when the inorganic layered compound is a clay mineral having a swelling property.

The outer layer A and the inner layer B of the packaging bag of the present invention
Are not particularly limited, and include resin, paper, aluminum foil, wood, cloth,
Examples include general base materials such as non-woven fabrics. The base resin used for the outer layer A and the inner layer B is polyethylene (low density, high density), ethylene-propylene copolymer, ethylene-butene copolymer, ethylene-hexene copolymer, ethylene-octene copolymer. , Polypropylene, ethylene-vinyl acetate copolymer, ethylene-methyl methacrylate copolymer, polyolefin resin such as ionomer resin, polyester resin such as polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, nylon-6, nylon-6 , 6, methaxylenediamine-adipic acid condensation polymer, amide resin such as polymethylmethacrylimide, acrylic resin such as polymethylmethacrylate, polystyrene, styrene-acrylonitrile copolymer, styrene-acrylonitril -Butadiene copolymer, styrene such as polyacrylonitrile, acrylonitrile resin, cellulose triacetate, hydrophobic cellulose resin such as cellulose diacetate, polyvinyl chloride, polyvinylidene chloride, polyvinylidene fluoride, halogen-containing resin such as Teflon, Hydrogen bonding resin such as polyvinyl alcohol, ethylene-vinyl alcohol copolymer, cellulose derivative, polycarbonate resin, polysulfone resin, polyether sulfone resin, polyether ether ketone resin, polyphenylene oxide resin, polymethylene oxide resin, liquid crystal resin, etc. The engineering plastic resins of

Of these, the outer layer A may be a single layer or a laminated film, and the outermost layer is preferably biaxially oriented polyethylene terephthalate. Further, a laminate of biaxially stretched polyethylene terephthalate and biaxially stretched nylon, etc. are preferably arranged. As the inner layer B,
It may be a single layer or a laminated film, and since the innermost layer of the bag generally has good heat-sealing property, it is a polyolefin resin such as polyethylene (low density, high density) or ethylene-propylene copolymer. Polymer, ethylene-butene copolymer, ethylene-hexene copolymer, ethylene-octene copolymer, polypropylene, ethylene-vinyl acetate copolymer, ethylene-methyl methacrylate copolymer, ethylene-ethyl acrylate, ionomer and the like are preferable. Used.

The moisture permeability ratio A / B of the outer layer A and the inner layer B is 2 or more, more preferably 3 or more. On the other hand, when it is less than 2, the oxygen barrier property after retort sterilization is poor, which is not preferable.

The method for laminating the intermediate layer C of the present invention on the substrate is not particularly limited. When the substrate is, for example, a film or sheet, a coating method of applying a coating liquid of the composition on the surface of the substrate, drying and heat treatment, a method of laminating the composition film afterwards, and the like are preferable. On the contrary, a method of extrusion laminating the A layer, the B layer and the like on the C layer is also preferably used. Further, the interface between the both may be treated with corona treatment or anchor coating agent.
As a coating method, a direct gravure method, a reverse gravure method, a micro gravure method, a roll coating method such as a two roll beat coating method, a bottom feed three reverse coating method, a doctor knife method, a die coating method, a dip coating method, and a bar coating method. Examples thereof include a coating method and a coating method combining these methods.

The thickness of the intermediate layer C varies depending on the type of the substrate and the desired barrier performance, but the dry thickness is 10 μm.
The following is preferable, and 1 μm or less is more preferable. (When the film thickness is 1 μm or less, it is difficult to cause film whitening during retort sterilization and the retort property is excellent, and when it is 1 μm or less, the transparency of the laminate is extremely high. It is more preferable for applications requiring transparency). The lower limit is not particularly limited, but is preferably 1 nm or more in order to obtain an effective gas barrier effect.

Further, within a range that does not impair the effects of the present invention,
The bag material may be mixed with various additives such as an ultraviolet absorber, a coloring agent and an antioxidant.

The shape of the packaging bag used in the present invention is not particularly limited. For example, shapes such as a three-sided sealed packaging bag, a four-sided sealed packaging bag, a pillow packaging bag, a gusseted packaging bag, and a standing pouch are preferably used. The bag-making method is not particularly limited, and various commercially available bag-making machines can be used.

[0032]

According to the present invention, it is composed of the outer layer A, the inner layer B and the intermediate layer C, and the C layer is composed of an inorganic layered compound having a particle size of 5 μm or less and an aspect ratio of 50 to 5000 and a high hydrogen bonding resin. And a layered film characterized by having a moisture permeability ratio A / B of A layer and B layer of 2 or more, a high level of gas barrier property and oxygen barrier property after retort sterilization that has never existed before. It is possible to obtain a packaging bag for retort which is excellent in It is also suitable for boiling sterilization.

As described in Example 2, improvement in oxygen barrier recovery after retort sterilization can be expected.

Further, the retort packaging bag containing the intermediate layer C of the present invention has remarkably excellent oxygen gas barrier property after retort sterilization, as compared with the ethylene-vinyl alcohol-based retort packaging bag, and the ethylene-vinyl alcohol packaging bag. The whitening of the film, which is a particular problem with packaging bags, is not seen. In addition, the oxygen barrier property is one digit higher than that of the polyvinylidene chloride-based retort packaging bag, and no delamination is observed in the polyvinylidene chloride-based packaging bag. As described above, it has excellent properties as compared with the packaging bags for retort foods currently on the market.

As the packaging material of the present invention, it is used for food such as packed rice, curry, stew and the like for boil and retort. In addition, miso, pickles, boiled fish, konjac, chikuwa, kamaboko, other processed marine products, meatballs, hamburgers, ham / sausage, tetra packs, rice cakes, and more, as well as pet food, pesticides / fertilizers, infusion packs, semiconductor packaging, Oxidizing chemical packaging,
It is used for applications such as precision material packaging such as medical, electronic, chemical, industrial material packaging such as machinery.

[0036]

The present invention will be described in detail below with reference to examples, but the present invention is not limited thereto.

The methods for measuring various physical properties are described below. [Oxygen permeability]: Oxygen permeability measuring device (OX-TRA
N 10 / 50A, manufactured by MOCON), and temperature was 23.7 ° C. (Outer layer A side humidity 60% RH, inner layer B side humidity 100
% RH). [Thickness measurement]: 0.5 μm or more was measured with a digital thickness meter. When the thickness is less than 0.5 μm, a weight analysis method (the weight measurement value of a film having a certain area is divided by the area and further divided by the specific gravity of the composition), or in the case of a laminate of the composition of the present invention and a substrate, , Elemental analysis method (a method for obtaining the ratio of the resin composition layer of the present invention to the base material from the ratio of the specific inorganic element analysis value (derived from the composition layer) of the laminate and the specific element fraction of the inorganic layered compound alone) It was [Particle size measurement]: Measured under the conditions of ultrafine particle size analyzer (BI-90, manufactured by Brookhaven Co., Ltd.), temperature of 25 ° C., and water solvent. The central diameter determined by the photon correlation method by the dynamic light scattering method was defined as the particle diameter L. [Aspect ratio calculation]: X-ray diffractometer (XD-5A,
Diffraction measurement was performed on the inorganic layered compound alone and the resin composition by a powder method using Shimadzu Corporation. Thus, the interplanar spacing (unit thickness) a of the inorganic layered compound was determined, and it was further confirmed from the diffraction measurement of the resin composition that the interplanar spacing of the inorganic layered compound was wide. Using the particle size L obtained by the above method, the aspect ratio Z is Z = L /
It was determined by the formula a.

[Example 1] Synthetic mica (tetrasilicic mica (NA-TS); manufactured by Topy Industries, Ltd.) was dispersed in ion-exchanged water (0.7 µS / cm or less) at 2.0 wt%. This is an inorganic layered compound dispersion liquid (liquid A). The particle size of the synthetic mica (NA-TS) is 977n.
m, the a value obtained from powder X-ray diffraction is 0.9557 nm, and the aspect ratio Z is 1043. In addition, polyvinyl alcohol (PVA117H; manufactured by Kuraray Co., Ltd., saponification degree; 99.6%, polymerization degree 1700) was added to ion-exchanged water (0.7 μS / cm).
The resin solution (solution B) is dissolved in the following) to a concentration of 2.0 wt%. Liquid A and liquid B were mixed so that the solid component ratio (volume ratio) of each was inorganic layered compound / resin = 3/7. Zirconium ammonium carbonate (manufactured by Daiichi Rare Elements Industry Co., Ltd .; Zircosol AC7 (15 in terms of zirconium oxide) was added to the mixed solution as a hydrogen bonding agent.
wt% aqueous solution)) was added to the mixed solution at a ratio of 1 mol of zirconium element to 15 mol of hydroxyl group of polyvinyl alcohol, and this was used as a coating liquid. Thickness 12
A μm polyethylene terephthalate (PET) film (Lumirror; manufactured by Toray Industries, Inc.), whose surface corona treatment was used as the layer A, was coated with a coating solution on this substrate film and gravure coated (test coater; Iseiki: Microgravure coating method, coating speed 2 m / min, drying temperature 10
0 ° C). The dry thickness of the coating layer was 0.7 μm. On the coating layer of the coating film, a urethane adhesive (Eunoflex J3: Sanyo Chemical Co., Ltd.) was used to dry-laminate a surface-corona-treated unstretched polypropylene film (Toray: Trefan NO: thickness 25 μm). A laminated film was obtained. A packaging bag having a width of 125 mm and a length of 180 mm was produced using the laminated film. 150 cc of pure water was inserted into the package. The heat-sealing conditions are a temperature of 208 ° C., a time of 0.5 seconds, and a width of 10 mm (heat sealer: FUJI IMPULSET230; FU).
JI MPULSE CO. LTD). A retort sterilization test of the packaging bag was performed. The retort sterilization conditions were 120 ° C., 2 kg / cm ² , and 30 min (Time oak car (high-speed hot water storage type sterilizer); manufactured by Sunplus). As a result, almost no change in appearance was observed.
(Table 1)

Example 2 The boil test of the packaging bag produced in Example 1 was conducted. The packaging bag was immersed in a water bath at 95 ° C. for 4 hours, and the change with time of the oxygen gas barrier property after boiling was measured. As a result, the oxygen permeability after 1 hour was 0.35 cc / m ² day · atm, after 2 hours was 0.26 cc / m ² · day · atm, and after 3 hours was 0.24 cc / m. ^{It was 2} · day · atm.
(Table 2)

[Comparative Example 1] EVOH-F film (15
Polyethylene terephthalate (PET) film (Lumirror; manufactured by Toray Industries, Inc.) having a thickness of 12 μm and surface-corona treated with μm and an ethylene content of 32 mol%; CPP) film (manufactured by Toray: Trefan NO: thickness 25 μm) was used as an inner layer, and a urethane adhesive (Eunoflex J3: manufactured by Sanyo Kasei) was used for dry lamination to obtain a laminated film. Horizontal 1 using the laminated film
A 25 mm × 180 mm vertical package was prepared. 150 cc of pure water was inserted into the packaging bag. Further, the heat sealing conditions are a temperature of 208 ° C., a time of 0.5 seconds, and a width of 10 mm (heat sealer: FUJI IMPULSET230; FUJ
I MPULSE CO. LTD). The retort sterilization conditions were 120 ° C., 2 kg / cm ² , and 30 min (manufactured by Time Oak Coker) (high-speed hot water storage type sterilizer); manufactured by Sunplus). As a result, the film turned white.
(Table 1)

[Comparative Example 2] Saran UB film (15 μm)
m; Asahi Kasei Co., Ltd., a surface-corona-treated polyethylene terephthalate (PET) film having a thickness of 12 μm (Lumirror; manufactured by Toray Industries, Inc.) as an outer layer, and a surface corona-treated unstretched polypropylene (CPP) film (made by Toray: A trephane NO: thickness of 25 μm) was used as an inner layer, and a urethane adhesive (Eunoflex J3: manufactured by Sanyo Kasei) was used for dry lamination to obtain a laminated film. A package having a width of 125 mm and a length of 180 mm was produced using the laminated film. 150 cc of pure water was inserted into the package. The heat-sealing conditions are a temperature of 208 ° C. and a time of 0.
5 seconds, width 10 mm (heat sealer: FUJI IMP
ULSET230; FUJI MPULSE CO. L
TD). Retort sterilization condition is 120 ℃, 2kg
/ cm ² , 30 min (time oak car (high-speed hot water storage type sterilizer); manufactured by Sunplus Co., Ltd.). As a result, the outer layer film was delaminated. (Table 1)

Comparative Example 3 The boil test of the packaging bag produced in Comparative Example 1 was conducted. The packaging bag was immersed in a water bath at 95 ° C. for 4 hours, and the change with time of oxygen barrier property after boiling was measured. As a result, the oxygen permeability after 1 hour is 2
It was 7.2 cc / m ² · day · atm, 2 hours later was 17.2 cc / m ² · day · atm, and 3 hours later was 10.7 cc / m ² · day · atm.
(Table 2)

Comparative Example 4 The packaging bag produced in Comparative Example 2 was subjected to the boil test. The packaging bag was immersed in a water bath at 95 ° C. for 4 hours, and the change with time of oxygen barrier property after boiling was measured. As a result, the oxygen permeability after 1 hour was 1.
8 cc / m ² · day · atm, and after 2 hours, 1.
8 cc / m is ² · day · atm, also after 3 hours was ^{1.8cc / m 2 · day · atm} .

[0044]

[Table 1]

[Table 2] ・ Biaxial polyethylene terephthalate (PET) film (water vapor transmission rate 50 g / m ² day: manufactured by Toray Industries, Inc .: Lumirror:
Thickness: 12 μm ・ Non-stretched polypropylene (CPP) film (water vapor permeability 1
4 g / m ² · day: Toray Industries, Inc .: Trefan NO: Thickness 25 μm)

[Brief description of drawings]

FIG. 1 is a conceptual diagram showing a film configuration of a cross section of a film of a retort packaging bag of the present invention.

FIG. 2 is a conceptual diagram showing a film configuration of a cross section of the film of the retort packaging bag of the present invention.

FIG. 3 is a graph schematically showing the relationship between the X-ray diffraction peak of an inorganic layered compound and the unit thickness a of the compound.

FIG. 4 is a graph schematically showing the relationship between the X-ray diffraction peak of a resin composition containing an inorganic layered compound and the interplanar spacing d of the composition.

FIG. 5 is an X-ray diffraction peak of a resin composition when the peak corresponding to the interplanar spacing d overlaps with a halo (or background) and is difficult to detect, and the interplanar spacing of the composition. It is a graph which shows the relationship with d typically.

FIG. 6 shows polyvinyl alcohol PVA117.
It is a graph which shows the X-ray diffraction peak of H / Kunipia F composition, and the graph which shows the X-ray diffraction peak of Kunipia F (montmorillonite).

FIG. 7 is a graph showing an X-ray diffraction peak (pattern of FIG. 4) of a composition having a surface spacing d = 19.62 angstrom.

FIG. 8 is a graph showing X-ray diffraction peaks (patterns in FIGS. 4 and 5) of a composition having an interplanar spacing d = 32.94 angstroms.

FIG. 9 is an X-ray diffraction peak of a composition having an interplanar spacing d of 44.13 Å or more (pattern of FIG. 5).
It is a graph which shows.

[Explanation of Codes] 1 outer layer A 2 middle layer C 3 inner layer B

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display location B65D 30/02 C08L 3/00 LAT 29/04 LGM // C08K 3/10 C08L 31/04 LDL ( 72) Inventor Toshiya Kuroda 2-10-1 Tsukahara, Takatsuki City, Osaka Prefecture Sumitomo Kagaku Kogyo Co., Ltd.

Claims (11)

[Claims] 1. An outer layer A, an inner layer B, and an intermediate layer C, wherein the C layer has a grain size of 5 μm or less and an aspect ratio of 50 to 50.
It is composed of a composition comprising 5000 inorganic layered compounds and a high hydrogen-bonding resin, and has a moisture permeability ratio A / A of layer A / B.
A retort packaging bag, wherein B is 2 or more. 2. The retort packaging bag according to claim 1, wherein the inorganic layered compound swells and cleaves in a solvent. 3. The retort packaging bag according to claim 2, wherein the inorganic layered compound is a swelling clay mineral. 4. The aspect ratio of the inorganic layered compound is 200.
The packaging bag for retort according to claim 1, 2 or 3, characterized in that 5. A retort packaging bag, wherein the volume ratio of the inorganic layered compound / high hydrogen bonding resin is in the range of (5/95) to (90/10). 6. The retort according to claim 1, wherein the high hydrogen-bonding resin has a weight percentage of hydrogen-bonding groups or ionic groups per unit weight of resin of 30% or more and 50% or less. Packaging bag. 7. The retort packaging bag according to claim 1, wherein the high hydrogen-bonding resin is polyvinyl alcohol or a polysaccharide. 8. The retort packaging bag according to claim 6, wherein the layer C contains a crosslinking agent for hydrogen-bonding groups. 9. The retort packaging bag according to claim 8, wherein the hydrogen-bonding group crosslinking agent is a zirconia compound. 10. The retort packaging bag according to claim 1, wherein the outer layer A is composed of biaxially oriented polyethylene terephthalate or a laminated film of biaxially oriented polyethylene terephthalate and biaxially oriented nylon. . 11. The retort packaging bag according to claim 1, wherein the inner layer B is made of a resin selected from unstretched polypropylene, unstretched polyethylene, and unstretched ethylene vinyl acetate copolymer.