JPH10249979A - Laminated film for packaging miso - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent generation of chlorine gas by preventing discoloring of miso or fermented soybean paste, preventing dissipation or transfer of aroma via a packaging material, further suppressing foam or thermal discoloring of the miso near a seal in a packaging step, and sufficiently appealing excellent transparency and freshness of the miso. SOLUTION: This film comprises a base material layer (A) formed of thermoplastic resin having a melting point or Vicat softening point of 180 deg.C or higher, and a gas barrier resin layer (B) provided at least on one surface of the layer (A) and formed by heat treating a film formed of at least one type of mixture selected from a group consisting of poly(meth)acrylate polymer, polyvinyl alcohol and sugar and the like. Further, a sealable resin layer (C) made of thermoplastic resin having a melting point of 110 deg.C or lower is provided on either one surface.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laminated film for packaging miso, and more particularly, to preventing discoloration of miso in the course of distribution of packaged products and prevention of dissipation and transfer of aroma components through packaging materials. The present invention relates to a transparent laminated film that can suppress foaming and thermal discoloration of miso in the vicinity of a seal portion in a packaging process and is particularly suitable for miso packaging.

[0002]

2. Description of the Related Art Today, many types of miso are packaged in a hermetically sealed package. However, the hermetically sealed package has a new problem that has not been seen in the days of barrel packing and weighing. The main ones are the swelling and browning phenomena in the distribution process of the packaged products, and in addition to these, dissipation and perfume of aroma components through the packaging material, foaming of miso near the seal part in the packaging process And thermal discoloration problems. Miso packaging may swell due to internal gas pressure or, in severe cases, cause the container to burst. The swelling in the distribution process of the miso package is mainly due to the re-fermentation of the remaining yeast. Many yeasts still remain in the aged miso, and when these grow and proliferate again, carbon dioxide is generated. Therefore, the problem of swelling is that the yeast is heat-sterilized before or after sealed packaging, or the yeast is sufficiently aged in the miso manufacturing process to reduce the number of yeasts, or heat-sterilized, and then sorbic acid is used as a spring inhibitor. Or add alcohol,
This can be solved by bacteriostasis.

However, problems such as browning and fragrance are
The situation has not yet been fully resolved.
The surface turns brown when miso is stored. This browning phenomenon gradually extends to the inside of the miso, and eventually the entire body turns black-brown. The browning of miso is mainly caused by the amino-carbonyl reaction between sugar and amino acids. Soybeans, rice, wheat, and the like, which are the raw materials for miso, are partially hydrolyzed by koji enzymes to produce sugars, amino acids, phenols, and carbonyl compounds. These components contained in the miso
It undergoes an amino-carbonyl reaction to produce 3-deoxyglucosone, which, through a more complex reaction pathway, eventually turns into a brown pigment called melanoidin (Maillard reaction). In this way, the browning of the miso gradually proceeds after preparation, throughout fermentation, aging, and storage. The browning reaction of miso proceeds without oxygen, but the presence of oxygen significantly promotes browning. Moreover, since browning is a chemical reaction, it is accelerated as the temperature increases. Miso has little coloring when the pH is around 4.5, but tends to be colored on the alkaline side or strong acidity. Metal ions such as copper ions and iron ions promote browning.

[0004] After fermentation and aging, miso is usually blended to adjust the quality, and then packaged and shipped. Even after packaging, a browning reaction occurs for the reasons described above.
If the miso browns during the distribution process, the commercial value of the package will be impaired. Further, as the discoloration of the miso progresses, the scent also changes to a roasted odor, and umami is lost and the quality is reduced. In order to prevent browning of the miso, the pH of the miso can be adjusted or the contamination of metal ions in the manufacturing process can be prevented to eliminate the coloring factor. There is a limit and the quality of miso may be impaired. As an effective method for preventing browning, a method of adding a sulfite is known, but since this is a bleaching agent, it is not preferable as a technique for maintaining the quality of miso.

Therefore, conventionally, after the miso is packaged, the miso is sealed with a non-breathable packaging material so as to prevent contact with oxygen as much as possible to prevent discoloration. Specifically, as a gas barrier layer, an ethylene-vinyl alcohol copolymer (EVOH) film or polyvinyl alcohol (P
VA) Polyvinylidene chloride (PVD) on both sides of the film
C) is used as a packaging material for miso (“Functional Food Packaging Technology Handbook”, Science Forum, 1
Published September 20, 989, pp. 76-92). The laminated film is usually composed of an outermost layer / gas barrier layer / seal layer, and typical examples thereof are OPP / EVOH
/ EVA, ONy / OV / PE. here,
OPP is a biaxially oriented polypropylene film,
VA is an ethylene-vinyl acetate copolymer film, ONy is a biaxially stretched nylon film, and PE
Is a polyethylene film. As the packaging form,
Pillow type packaging, three-side seal packaging, four-side seal packaging,
Gusset-type four-side seal packaging is available.

However, EVOH films and PVD
In any of the C-coated PVA films, the oxygen gas barrier property is reduced under high humidity conditions, and the browning of the miso is promoted.
Moreover, these conventional gas barrier films lack the barrier properties of the fragrance components, and the fragrance components of the miso are removed from the packaging bag to lose the flavor or the smell of the miso is transferred to other foods. There is a problem. The PVDC-coated PVA film is colored by heat sealing at the time of filling,
Since coloring over time also occurs, the miso looks apparently colored, and the commercial value of the package is impaired. Further, since the PVDC-coated PVA film contains chlorine atoms, chlorine gas is generated during incineration of waste treatment. As described above, the conventional packaging materials do not have sufficient oxygen gas barrier properties, and the browning of the miso progresses with an increase in the amount of oxygen in the packaging, and the barrier properties of the aroma components of the miso are low. In addition to impairing the flavor, there is a problem that the smell is transferred to other foods, and the packaging material has a high cloudiness, so that the freshness of the miso cannot be sufficiently appealed when the packaged goods are displayed at the store.

By the way, the present inventors have proposed that a gas barrier layer formed from a mixture of poly (meth) acrylic acid or a partially neutralized product thereof and PVA, a gas barrier layer formed of poly (meth) acrylic acid or It has been found that a laminate in which a gas barrier film formed from a mixture of the partially neutralized product and a saccharide is arranged is suitable as a packaging material for meat products, beverages, pharmaceuticals, and the like, and has been previously proposed (Japanese Patent Application Laid-Open No. JP-A-7-205279, JP-A-7-251
485). However, the laminates specifically disclosed in these publications have, for example, a seal layer made of a high-melting-point resin disposed thereon, and are not necessarily optimal as a packaging material for miso. If the sealing temperature at the time of filling the miso is high, the miso near the sealing part may foam,
Coloring causes a problem that the appearance of the package is impaired.

[0008]

SUMMARY OF THE INVENTION An object of the present invention is to prevent discoloration of miso during the distribution process of a packaged product, and to prevent dissipation and transfer of aroma components through a packaging material. In addition, foaming and thermal discoloration of the miso in the vicinity of the seal portion in the packaging process can be suppressed, and the transparency is excellent, and the freshness of the miso can be sufficiently appealed. It is an object of the present invention to provide a laminated film for packaging miso that does not have any. We have:
As a result of intensive research to overcome the problems of the prior art, at least one surface of a base layer made of a heat-resistant resin was formed from a mixture of a poly (meth) acrylic acid-based polymer and PVA and / or saccharide. It has been found that the above object can be achieved by providing a gas barrier resin layer obtained by heat-treating the film and further providing a sealing resin layer made of a low melting point thermoplastic resin on one of the surfaces. When a resin layer having a higher melting point than the sealing resin is provided as the outermost layer, the effect of preventing discoloration of the miso over time and the barrier property of the fragrance component can be further improved. The present invention has been completed based on these findings.

[0009]

According to the present invention, at least one surface of a base material layer (A) formed of a thermoplastic resin having a melting point or a Vicat softening point of 180 ° C. or more is coated with a poly (meth) acrylic acid-based material. A gas barrier resin layer (B) obtained by heat-treating a film formed from a mixture of a polymer and at least one selected from the group consisting of polyvinyl alcohol and saccharides is provided, and further, on one of the surfaces, There is provided a laminated film for miso packaging, comprising a laminated film provided with a sealing resin layer (C) made of a thermoplastic resin having a melting point of 110 ° C. or less.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION In the present invention, a poly (meth) acrylic acid-based polymer is provided on one or both sides of a base layer (A) formed of a heat-resistant thermoplastic resin as a packaging material for hermetic packaging of miso. And a gas barrier resin layer (B) formed by heat-treating a film formed from a mixture of at least one selected from the group consisting of polyvinyl alcohol and saccharides, and further having a melting point on one surface. Is 11
A laminated film provided with a sealing resin layer (C) made of a thermoplastic resin having a low melting point of 0 ° C. or lower is used.

The substrate layer (A) The gas barrier resin layer (B) is usually formed by casting a solution of the mixture on the substrate layer (A), drying the solution, forming a film, And a heat treatment. Therefore, the base material layer (A) needs to have heat resistance enough not to soften or melt under heat treatment conditions. Therefore, in the present invention, the melting point or the Vicat softening point is 180 ° C.
A film or sheet formed from the above thermoplastic resin is used as the base layer (A). In addition, the base material layer (A)
Is required to have excellent interlayer adhesion with the gas barrier resin layer (B) after the heat treatment, and also to have excellent transparency to sufficiently appeal the freshness of the miso.

The thermoplastic resin forming the base material layer (A) may be, for example, polyethylene terephthalate (PET), nylon 6, nylon 66, nylon 12, nylon 6.66 copolymer, nylon 6.1
Nylon such as 2 copolymer, polyphenylene sulfide, and the like can be given. From the viewpoints of heat resistance, interlayer adhesion with the gas barrier resin layer (B), and transparency,
The thermoplastic resin forming the base material layer (A) is preferably P
ET and nylon. The base material layer (A) is made of stretched PET
Particularly preferred are films or stretched nylon films. Although the thickness of the base material layer (A) is not particularly limited, it is usually about 5 to 100 μm, preferably about 5 to 50 μm, more preferably about 8 to 30 μm from the viewpoint of strength, flexibility, transparency, economy, and the like. .

Gas barrier resin layer (B) In the present invention, the gas barrier layer is a film formed from a mixture of a poly (meth) acrylic acid polymer and at least one selected from the group consisting of polyvinyl alcohol and saccharides. Is used as the gas barrier resin layer.

<Poly (meth) acrylic acid-based polymer> The poly (meth) acrylic acid-based polymer is at least one selected from the group consisting of poly (meth) acrylic acid and partially neutralized poly (meth) acrylic acid. One polymer is used. The poly (meth) acrylic acid used in the present invention is a compound containing two or more carboxyl groups, and specifically, polyacrylic acid, polymethacrylic acid,
It is a copolymer of acrylic acid and methacrylic acid, or a mixture of two or more of these. Suitable examples include homopolymers of acrylic acid or methacrylic acid and copolymers of both. Although the number average molecular weight of the poly (meth) acrylic acid is not particularly limited,
A range from 000 to 250,000 is preferred.

The partial neutralization is desirably carried out using a poly (meth) acrylic acid-based polymer at least one selected from the group consisting of sodium hydroxide, potassium hydroxide and ammonium hydroxide. In such an embodiment, the degree of neutralization is more than 0 and 20% or less (furthermore, 0%
Over 18%). Here, the “degree of neutralization” is obtained by the following equation. Degree of neutralization = (X / Y) × 100 (%) X: Total number of moles of neutralized carboxyl groups in 1 g of partially neutralized poly (meth) acrylic acid-based polymer. Y: the total number of carboxyl groups before partial neutralization in 1 g of the poly (meth) acrylic acid-based polymer to be partially neutralized.

Further, a metal salt may be added to the poly (meth) acrylic acid-based polymer for the purpose of improving the oxygen barrier property of the obtained heat-treated film. The metal salt is desirably performed using at least one selected from the group consisting of monovalent metal salts and hypophosphites. The amount of metal salt added
Both the monovalent metal salt and the hypophosphite are preferably in the range of 1.0 × 10 ^{−5 to} 3.0 × 10 ⁻³ mol / g based on the weight of the heat-treated film.

<Polyvinyl Alcohol> The polyvinyl alcohol (PVA) used in the present invention has a degree of saponification of usually 95% or more, preferably 98% or more, and an average degree of polymerization of usually 300 to 2500, preferably 300 to 1500. It is. A mixed system of PVA having a high degree of saponification and a poly (meth) acrylic acid-based polymer is excellent in compatibility, and for example, a uniform mixed solution can be obtained when it is made into an aqueous solution.

<Saccharides> As saccharides, biopolymers synthesized in ecosystems by condensation polymerization of various monosaccharides, and those obtained by chemically modifying them can be used. Specific examples of such saccharides include, for example, monosaccharides, oligosaccharides, sugar alcohols, and polysaccharides. Sorbitol, dextrin, water-soluble starch, etc. can be suitably used from the viewpoint of the oxygen gas barrier property of the obtained heat-treated film.

<Formation of Gas Barrier Resin Layer (B)> A mixture of a poly (meth) acrylic acid-based polymer and at least one selected from the group consisting of PVA and saccharides is obtained by dissolving each component in water. A method of mixing, a method of mixing an aqueous solution of each component, a method of polymerizing a (meth) acrylic acid monomer in an aqueous solution of PVA and / or a saccharide, and a method of PVA.
And / or a method in which (meth) acrylic acid monomer is polymerized in an aqueous solution of a saccharide, and then partially neutralized with an alkali. When these mixtures are used as an aqueous solution, a uniform solution can be obtained. The mixture may be prepared using a solvent such as alcohol or a mixture of alcohol and water in addition to water. The mixing ratio of each component is usually 10 to 9 poly (meth) acrylic acid-based polymer.
5 parts by weight, and 5 to 90 parts by weight of at least one selected from the group consisting of PVA and saccharides. When a mixture of a poly (meth) acrylic acid-based polymer and PVA is used, the blending ratio (weight ratio) is preferably 90:10 to 1
0:90, more preferably 80:20 to 20:80. When a mixture of a poly (meth) acrylic acid-based polymer and a saccharide is used, the mixing ratio (weight ratio) is preferably 90:10 to 20:80, and more preferably 90: 1.
0-40: 60, most preferably 85: 15-50: 5
0.

In order to form a film (film) from these mixtures, a method of casting an aqueous solution of the mixture on the base material layer (A) and drying to form a film (solution casting method) is employed. Is preferable because a dried film excellent in transparency can be easily obtained. When the solution casting method is employed, the polymer concentration is usually 0.5 to 60% by weight, preferably about 5 to 30% by weight. When preparing an aqueous solution, a solvent other than water, such as alcohol, a softener, or the like may be appropriately added, if desired. The thickness of the dry film is not particularly limited, but is usually 0.5 to 50 μm, preferably 0.5 to 50 μm, from the viewpoint of balance between gas barrier properties and transparency.
To 30 μm, more preferably about 0.5 to 10 μm.

Since the dried film is soluble in cold or boiling water and has insufficient gas barrier properties, it is subjected to a heat treatment. In the heat treatment, the base material layer (A) having a dry film formed from the mixture is kept at a predetermined temperature for a predetermined time under a dry heat atmosphere such as hot air or a heating furnace, or in contact with a heating body such as a hot roll. It is done by doing. The heat treatment temperature (T) is usually 373 to 623K (100 to 350K).
° C), preferably 433-573K (160-300K).
C), more preferably 453-523K (180-25
0 ° C). The heat treatment time (t) is usually 1 second to 2 seconds.
0 hour, preferably 1 second to 30 minutes, more preferably 3 to 120 seconds. Generally, the heat treatment conditions are as follows:
When the heat treatment temperature is low, heat treatment is performed for a long time, and as the heat treatment temperature increases, the heat treatment time is shortened. It is difficult to obtain a film having high gas barrier properties and water resistance by a heat treatment at a low temperature for a short time, and a heat treatment at a high temperature for a long time causes discoloration or decomposition of the film. More specifically, the following heat treatment conditions are preferred.

The oxygen permeability of the packaging material for miso is 3
20 ml (STP) at 0 ° C and 80% relative humidity (RH)
/ M ² · day · atm. The oxygen-permeability of the heat-treated film of the present invention varies depending on the heat-treating conditions.
The oxygen permeability in H is 20 ml (STP) / m ² · d
The condition of ay · atm or less can be determined by the following equation. (A) logt ≧ −0.0253 × T + 11.2 (b) 373 ≦ T ≦ 623 [where T is a heat treatment temperature (K) and t is a heat treatment time (minute)]. ] More preferred thickness of the heat-treated film is 2 µm, 30 ° C, 80
% RH is 10 ml (STP) / m
^{It is 2} * day * atm or less, and the heat treatment condition at that time can be determined by the following equation. (C) logt ≧ −0.0344 × T + 15.9 (b) 373 ≦ T ≦ 623 [where T is a heat treatment temperature (K) and t is a heat treatment time (minute)]. ] Particularly preferred thickness of the heat-treated film is 2 μm, 30 ° C., 80%
The oxygen permeability at RH is 1 ml (STP) / m ² ·
day · atm or less, and the heat treatment conditions at that time are as follows:
It can be determined by the following equation. (D) logt ≧ −0.0643 × T + 31.6 (b) 373 ≦ T ≦ 623 [where T is a heat treatment temperature (K), and t is a heat treatment time (minute)]. ]

By these heat treatments, the dried film formed from the above mixture is provided with a high degree of gas barrier property and can obtain water resistance, and is insoluble in not only cold water but also boiling water. Become. The heat-treated film does not dissolve even when immersed in boiling water at 95 ° C. for 10 minutes. The thickness of the heat-treated film is almost the same as the thickness of the dried film. By impregnating the above-mentioned heat-treated film with polyvalent metal ions such as calcium and magnesium, the oxygen gas barrier property can be further improved. Specifically, there is a method of immersing the heat-treated film in a medium containing the metal ions, for example, water. More specifically, the heat-treated film is placed in an aqueous solution containing a polyvalent metal compound (eg, chloride, hydroxide) at a concentration of 0.1 to 100 g / liter.
A method of immersing at a temperature of 100 to 100 ° C, preferably 30 to 100 ° C, more preferably 50 to 100 ° C for 10 seconds to 4 hours, preferably 1 to 60 minutes. The presence of the metal in the heat-treated film can be confirmed by an infrared absorption spectrum. That is, when metal ions are present in the heat-treated film, the intensity ratio of the absorption at 1560 cm ^-1 derived from the carboxylate to the absorption at 1560 cm ^-1 derived from the carboxyl group of the polyacrylic acid-based polymer (Abs 1560) / Abs1700).

The gas barrier resin layer (B) may be formed as a film on a support different from the substrate layer (A), and may be laminated on the substrate layer (A). In this case, as a lamination method, a dry lamination method of both films and an extrusion coating method of a base material layer are employed. However, the above-described laminating method by the solution casting method is preferable because a laminated film having excellent interlayer adhesion can be easily obtained. The gas barrier resin layer (B) is usually provided on one surface of the base material layer (A), but may be provided on both surfaces of the base material layer (A) when a high degree of gas barrier property is desired. . The total thickness of the two layers is preferably 5 to 50 μm, more preferably 5 to 40 μm, and particularly preferably about 10 to 30 μm in terms of balance between strength, gas barrier properties, transparency, flexibility, and economy. It is desirable.

Sealing Resin Layer (C) In the present invention, on one side (one side) of a laminated film of a substrate layer (A) and a gas barrier resin layer (B)
Is provided with a sealing resin layer (C). The layer configuration in this case includes A / B / C, B / A / C, and B / A / B /
C can be mentioned. As the thermoplastic resin forming the sealing resin layer (C), a low melting point thermoplastic resin having a melting point of 110 ° C. or less is used. In the field of packaging materials using plastic films, the heat sealing method is generally adopted, but miso is a hydrated material. Impair. In addition, since browning of miso is more likely to occur as the temperature increases, if the heat sealing temperature is too high, the miso in the vicinity of the sealed part of the package may be more discolored than other parts. Therefore, in order to use the laminated film for hermetic packaging of miso, it is necessary to form a sealing resin layer with a thermoplastic resin having a low melting point.

More specifically, for miso packaging, if a low melting point thermoplastic resin having a melting point of 110 ° C. or less is used,
It was found that no foaming or discoloration occurred. The melting point of the thermoplastic resin is preferably 60 to 110 ° C, more preferably 6 to 110 ° C.
The temperature is 0 to 105 ° C, particularly preferably 60 to 100 ° C.
In order to obtain a transparent laminated film, it is preferable to use a thermoplastic resin having excellent transparency for the sealing resin layer (C). Examples of thermoplastic resins which can be heat-sealed and have good transparency include, for example, ethylene / vinyl acetate copolymer, ethylene / acrylic acid copolymer, ethylene / methacrylic acid copolymer, ethylene / acrylic acid salt Copolymers, ethylene / methacrylate copolymers, ethylene / ethyl acrylate copolymers, ethylene / ethyl methacrylate copolymers and the like having a melting point of 110 ° C. or lower can be given.

The sealing resin layer (C) is adjacent to the base material layer (A) or the gas barrier resin layer (B) by a dry laminating method or an extrusion coating method, with or without an adhesive layer. Laminate. The thickness of the sealing resin layer (C) is not particularly limited, but is preferably 10 μm or more from the viewpoint of sealing strength, and preferably 200 μm or less from the viewpoint of flexibility, transparency, and economy. This thickness is more preferably from 10 to 150 μm, particularly preferably from 10 to 100 μm. As the adhesive, various adhesives such as urethane, acrylic, and polyester generally used for dry lamination of various films can be used.

Outer Layer (D) The laminated film of the present invention may have, if desired, a heat-resistant material having a higher melting point than the thermoplastic resin forming the sealable resin layer on the surface opposite to the sealable resin layer (C). An outer layer (D) made of a plastic resin can be provided. By providing the outer layer (D), the strength can be increased or the water vapor barrier property can be imparted. The thermoplastic resin for forming the outer layer (D) is formed of, for example, a heat-sealing bar using a heat-sealing bar so that the heat-sealing can be easily performed by the sealing resin layer (B). Use a thermoplastic resin having a higher melting point than the thermoplastic resin to be formed. The thermoplastic resin used for the outer layer preferably has excellent transparency from the viewpoint of the transparency of the laminated film.

Examples of the thermoplastic resin forming the outer layer (D) include PET, nylon, and polypropylene. The outer layer (D) is preferably an oriented polypropylene film (OPP) for imparting water vapor barrier property, and is preferably an oriented nylon film (OPP) for imparting strength.
Ny) is preferred. The outer layer (D) is laminated adjacent to the base material layer (A) or the gas barrier resin layer (B) by a dry laminating method or an extrusion coating method with or without an adhesive layer. The thickness of the outer layer (D) is 10 μm or more from the viewpoint of strength and water vapor barrier property, and 100 μm from the viewpoint of transparency, flexibility, and economy.
The following is preferable. This thickness is more preferably from 10 to 50 μm.

Laminated Film The laminated film of the present invention may be, for example, A / B / C, B
/ A / C, B / A / B / C, D / A / B / C, D
/ B / A / C and D / B / A / B / C are multilayer films (adhesive layer is omitted). The essential requirement of the laminated film of the present invention is that the sealing resin layer (C) is provided as the innermost layer, and the base material layer (A) and the gas barrier resin layer (B) are provided adjacent to each other. However, various intermediate layers and additional layers may be present as necessary within a range that does not impair the object of the present invention. The outer layer (D) generally preferably forms the outermost layer. Various additives such as an antioxidant, a lubricant, an ultraviolet absorber, a pigment, a filler and an antistatic agent can be added to each layer of the laminated film of the present invention, if desired. Also, gloss,
Various films, coating layers, and the like may be provided in order to impart functions such as anti-fogging property and ultraviolet ray blocking property. To seal and package miso using the laminated film of the present invention, a bag-like container is formed by pillow type packaging, three-side seal packaging, four-side seal packaging, gusset-type four-side seal packaging, and filling with miso. Is preferred. Various sealing methods such as heat sealing, impulse sealing, high-frequency sealing, and ultrasonic sealing can be adopted as the sealing method.

[0031]

In the conventional sealed packaging of miso, the oxygen gas barrier property is not sufficient, and the browning of the miso progressed with an increase in the amount of oxygen inside the packaged product over time. Also, in conventional sealed packaging, the barrier properties of the flavor components of miso are low,
There is a problem that not only does the flavor of the miso deteriorate, but also the smell of the miso is transferred to other foods. Furthermore, the packaging material has a high cloudiness, so that there is a problem that the freshness of the miso cannot be appealed at the time of display at the store. When a resin having a high melting point is used as the sealing layer, the sealing temperature is high, so that the miso near the periphery of the sealing foams and, in some cases, causes a problem of coloring.

On the other hand, in the present invention, by adopting the above-mentioned constitution, the oxygen gas barrier property higher than that of the conventional packaging material can be exhibited not only under the low humidity condition but also under the high humidity condition. Browning can be suppressed more effectively. Further, since the laminated film of the present invention is excellent in the barrier property of the fragrance component, the flavor of the miso is maintained, the flavor is not transferred to other foods, and the quality is maintained for a long time. The laminated film of the present invention is excellent in transparency and has no coloring due to heat sealing, so that the original color and freshness of the miso can be accurately appealed and the commercial value can be increased. In the laminated film of the present invention, foaming and discoloration of the miso in the vicinity of the seal portion are prevented, and the appearance of the miso package is not impaired. Further, since the laminated film of the present invention does not contain chlorine atoms, it does not generate chlorine gas during incineration, and is environmentally friendly.

[0033]

The present invention will be described more specifically below with reference to examples and comparative examples. The evaluation methods of various physical properties are as follows. (1) Temporal change of color tone of miso A pouch (10 cm x 20 cm) was prepared from a laminated film, and 300 g of miso was vacuum-packaged. After storing this miso-filled pouch in an atmosphere of 30 ° C. and 90% RH for 20 days,
The surface color of the miso was measured and compared with that before storage. The measurement was taken out of the packaging and the color difference of the miso itself was measured. Nippon Denshoku Industries Co., Ltd. $ 80 COLOR MEA
Using a SURING SYSTEM (color difference meter), the ΔY value was measured by the following equation. ΔY value = (Y value of miso after 20 days) − (Y value of miso before filling) (2) Aroma component barrier property As described above, a pouch (10 cm × 10 5
cm) and filled with 5 g of miso. The pouch was placed in an air collecting bottle (500 cm ³ ) and left at 23 ° C. in an atmosphere of 60% RH for 3 days.
The barrier property was measured using a portable type odor sensor XP-329 manufactured by KK. The numerical value indicates that the larger the value, the higher the permeability of the fragrance component. (3) State of appearance by sealing temperature The state of appearance of miso by sealing temperature was observed. The sealing time was 5 seconds and the sealing pressure was 1 kg / cm ² . The appearance near the seal portion was observed and evaluated according to the following criteria. ：: Neither foaming nor discoloration of the miso near the seal portion is observed. ×: Foaming of the miso near the seal portion is observed. (4) Measurement of the intensity ratio (Abs1560 / Abs1700) of the infrared absorption derived from the carboxyl group of the polyacrylic acid-based polymer and the infrared absorption derived from the carboxylate salt. The infrared absorption spectrum is FT- manufactured by Perkin-Elmer.
Using IR1710, the measurement method was the ATR method (total reflection spectrum of the surface). Using the obtained straight line connecting 1800 cm ^-1 and 1500 cm ^-1 in the infrared absorption spectrum chart as a baseline, the absorption intensity of the carboxyl group of the polyacrylic acid-based polymer at 1700 cm ^{-1 and} the absorption of the carboxylate at 1560 cm ^-1 . The strength was determined and the latter was divided by the former.

Example 1 (1) Polyacrylic acid [Toa Gosei Co., Ltd .; molecular weight: 15]
000] and starch (primary grade, manufactured by Wako Pure Chemical Industries, Ltd.) in 15% by weight, respectively, and their weight ratio was 70:30.
And mixed so that Further, 1.3 × 10 ⁻³ mol / g of sodium hypophosphite [manufactured by Wako Pure Chemical Industries, Ltd.] based on the weight of the mixed resin solids was added. This mixed aqueous solution was applied on a stretched PET film (thickness: 12 μm) and dried to obtain a dry film having a thickness of 2 μm. This dried film was heat-treated with hot air (at 230 ° C. for 15 seconds). Thus, the dried film is made water-resistant and has an oxygen gas permeability of 1 ml (STP) / m ² · day · atm (30
(80 ° C., 80% RH) to form a gas barrier resin layer having a high oxygen gas barrier property. Hereinafter, this gas barrier resin layer is referred to as resin (b). (2) Ethylene / vinyl acetate copolymer [Evatate manufactured by Sumitomo Chemical Co., Ltd .; vinyl acetate content: 5% by weight, melting point: 104] on the resin (b) surface of the PET / resin (b) laminated film prepared above. [Deg.] C.] with an adhesive [Adcoat AD353 manufactured by Toyo Morton Co., Ltd.]
A, and dry-laminated via a curing agent CAT-10]. Using the laminated film thus obtained,
Physical properties were measured. Table 1 shows the results.

[Examples 2 to 6] In Example 1, an ethylene / vinyl acetate copolymer (Evatate manufactured by Sumitomo Chemical Co., Ltd .; vinyl acetate content: 5% by weight, melting point: 104 ° C.) forming a sealing resin layer was used. Ethylene-vinyl acetate copolymer [Evatate manufactured by Sumitomo Chemical Co., Ltd .; vinyl acetate content: 10% by weight, melting point: 95 ° C.] (Example 2), ethylene-acrylic acid copolymer [Escol manufactured by Exxon Chemical Co., Ltd.] Acrylic acid content 6% by weight, melting point 103 ° C.) (Example 3), ethylene / ethyl acrylate copolymer [Lexlon manufactured by Nippon Petrochemical; ethyl acrylate content 5% by weight, melting point 109 ° C.] (Example 4) ), An ethylene / methacrylic acid copolymer [nuclel manufactured by Mitsui / DuPont Chemical Co., Ltd .; methacrylic acid content: 9% by weight, melting point: 98 ° C.] (Example 5); A laminated film was prepared in the same manner as in Example 1 except that a len-methacrylate copolymer (Sumitomo Chemical Co., Ltd., Aklift; methacrylate content: 10% by weight, melting point: 100 ° C.) (Example 6) was used. It was evaluated similarly. Table 1 shows the results.

Example 7 A 15% by weight aqueous solution of each of polyacrylic acid (manufactured by Toagosei Co., Ltd .; molecular weight: 150,000) and starch (primary grade manufactured by Wako Pure Chemical Industries, Ltd.) was prepared.
Both were mixed at a weight ratio of 80:20. Further, 1.3 × 10 ⁻³ m with respect to the weight of the mixed resin solid content.
ol / g sodium hypophosphite [manufactured by Wako Pure Chemical Industries, Ltd.]
Was added. This mixed aqueous solution is applied to one side of a stretched PET film (thickness: 12 μm), dried, and
To obtain a dried film. Heat treatment of this dried film with hot air (2
(30 ° C. for 15 seconds) to make it water-resistant. Next, this heat-treated film was immersed in a magnesium hydroxide aqueous solution having a concentration of 1 g / liter at 90 ° C. for 10 minutes. The oxygen gas permeability of the heat-treated film immersed in this way is 0.1 ml (STP)
/ M ² · day · atm (30 ° C., 80% RH), and a gas barrier resin layer having a high oxygen gas barrier property was formed. Hereinafter, this gas barrier resin layer is referred to as resin (c). Hereinafter, a laminated film was prepared in the same manner as in Example 1 (2). Table 1 shows the results.

Example 8 (1) Polyacrylic acid (manufactured by Toagosei Co., Ltd .; molecular weight: 15)
000] with 10 mol% of sodium hydroxide [manufactured by Wako Pure Chemical Industries, Ltd.] and distilled water based on the carboxyl group, and a partially neutralized sodium polyacrylate having a degree of neutralization of 10 mol% ( A 15% aqueous solution of PAANA) was prepared. Separately, distilled water was added to PVA [Bhopal 105 manufactured by Kuraray Co., Ltd .; saponification degree 98.5 ± 0.5%, polymerization degree 500] to prepare a 15% aqueous solution of PVA. These partially neutralized sodium polyacrylate aqueous solution and PVA aqueous solution were mixed at a weight ratio of 70:30. This mixed aqueous solution was applied to one surface of a stretched PET film (thickness: 12 μm) and dried to obtain a dry film having a thickness of 2 μm. This dried film was heat-treated with hot air (at 230 ° C. for 15 seconds).
In this way, the dried film is made waterproof and has an oxygen gas permeability of 1 ml (STP) / m ² · day · atm.
A gas barrier resin layer having a high oxygen gas barrier property (30 ° C., 80% RH) was formed. Hereinafter, this gas barrier resin layer is referred to as resin (a). (2) On the resin (a) surface of the PET / resin (a) laminated film prepared above, an ethylene / vinyl acetate copolymer [Evatate manufactured by Sumitomo Chemical Co., Ltd .; vinyl acetate content 5% by weight, melting point 104] [Deg.] C.] with an adhesive [Adcoat AD353 manufactured by Toyo Morton Co., Ltd.]
A, via a curing agent CAT-10], and dry-laminated to form a laminated film. Table 1 shows the results.

[Embodiment 9] In the embodiment 1, the PET /
On the PET surface of the laminated film of the resin (b), a 50 μm thick film made of an ethylene / vinyl acetate copolymer was
A laminated film was prepared and evaluated in the same manner as in Example 1 except that dry lamination was performed via an adhesive. Table 1 shows the results.

Example 10 In Example 1, the stretching P
A laminated film was prepared and evaluated in the same manner as in Example 1 except that the ET film was replaced with a stretched nylon film (Toyobo Co., Ltd., Harden film; thickness: 20 μm), and the heat treatment conditions were changed to 180 ° C. for 5 hours. did. Table 1 shows the results
Shown in

[Example 11] In Example 9, the stretched nylon / resin (b) laminated film was coated on the stretched nylon surface with a thickness of 50 μm of ethylene / vinyl acetate copolymer.
A laminated film was prepared and evaluated in the same manner as in Example 1, except that the film m was dry-laminated via an adhesive. Table 1 shows the results.

[Embodiment 12] In the embodiment 1, the PET was used.
A laminated film was prepared and evaluated in the same manner as in Example 1, except that a stretched nylon film (thickness: 20 μm) was further laminated on the surface as an outermost layer via an adhesive. Table 1 shows the results.

[Thirteenth Embodiment] In the first embodiment, the PET
On the surface, as an outermost layer, a stretched polypropylene film [Pyrene film OT manufactured by Toyobo Co., Ltd .;
m], a laminated film was prepared in the same manner as in Example 1 except that dry lamination was performed via an adhesive, and the same evaluation was performed. Table 1 shows the results.

Comparative Example 1 Stretched polypropylene film (thickness: 20 μm), EVOH (thickness: 15 μm), and ethylene / vinyl acetate copolymer [Evatate manufactured by Sumitomo Chemical Co., Ltd .; vinyl acetate content: 5% by weight, melting point: 104 ° C.] Was dry-laminated via an adhesive to obtain a laminated film. Table 1 shows the results.

Comparative Example 2 Stretched polypropylene film (thickness: 20 μm), polyvinylidene chloride-coated PVA
[KPVA; Embroider OV manufactured by Unitika Ltd .; thickness 1
5 μm], and a 50 μm thick film made of an ethylene / vinyl acetate copolymer [Evatate manufactured by Sumitomo Chemical Co., Ltd .; vinyl acetate content 5% by weight, melting point 104 ° C.] is dry-laminated via an adhesive to form a laminated film. I got Table 1 shows the results.

Comparative Example 3 In Example 1, an ethylene / vinyl acetate copolymer (Evatate manufactured by Sumitomo Chemical Co., Ltd .; vinyl acetate content: 5% by weight, melting point: 104 ° C.) was used as the sealing resin layer instead of the film. , Unstretched polypropylene film [Pyrene film CT manufactured by Toyobo Co., Ltd .;
A laminated film was prepared and evaluated in the same manner as in Example 1 except that the temperature was 50 ° C.]. Table 1 shows the results.

Comparative Example 4 In Example 1, an ethylene / vinyl acetate copolymer (Evatate manufactured by Sumitomo Chemical Co., Ltd .; vinyl acetate content: 5% by weight, melting point: 104 ° C.) was used as the sealing resin layer instead of the film. , Linear low-density polyethylene film [Sumikasen α manufactured by Sumitomo Chemical Co., Ltd .; thickness 50
μm, melting point: 120 ° C.], and a laminated film was prepared and evaluated in the same manner as in Example 1. Table 1 shows the results.

[0047]

[Table 1]

(Footnote) (1) #: thickness (unit: μm) (2) Abs1560 / Abs1700: 1700 cm derived from the carboxyl group of the polyacrylic acid-based polymer
1560 cm from carboxylate for absorption of ^-1
Represents the absorption intensity ratio of ^-1 . (3) PET: stretched polyethylene terephthalate film (thickness: 12 μm) (4) ONy: stretched nylon film (thickness: 20 μm)
[Harden film manufactured by Toyobo Co., Ltd.] (5) OPP: stretched polypropylene film (thickness: 20)
μm) [Pyrene film-OT manufactured by Toyobo Co., Ltd.] (6) Resin (a): heat-treated film of a mixture of partially neutralized sodium polyacrylate and PVA (thickness: 2 μm) (7) Resin (b): polyacryl Heat treated film of mixture of acid, starch and sodium hypophosphite (thickness 2 μm) (8) Resin (c): heat treated film containing magnesium ion in resin (b) (thickness 2 μm) (9) EVA (1) ): Ethylene / vinyl acetate copolymer [Evatate manufactured by Sumitomo Chemical Co., Ltd .; vinyl acetate content: 5% by weight, melting point: 104 ° C.] Film (thickness: 50 μm) (10) EVA (2): Ethylene / vinyl acetate copolymer [ Evatate manufactured by Sumitomo Chemical Co., Ltd .; vinyl acetate content: 10% by weight, melting point: 95 ° C.) Film (thickness: 50 μm) (11) EAA: ethylene / acrylic acid copolymer [Exxon Chemical Escol; Acrylic acid content: 6% by weight, melting point: 103 ° C.] Film (thickness: 50 μm) (12) EEA: Ethylene / ethyl acrylate copolymer [Nippon Petrochemical Co., Ltd .; Lexuron; Ethyl acrylate content: 5% by weight; Melting point 109 ° C] film (thickness 50
μm) (13) EMAA: ethylene-methacrylic acid copolymer [Nucrel manufactured by Mitsui-Dupont Chemical Co., Ltd .; methacrylic acid content 9% by weight, melting point 98 ° C.]
(14 μm) (14) EMMA: ethylene / methacrylate copolymer [Aclift manufactured by Sumitomo Chemical Co., Ltd .; methacrylate content 1
0% by weight, melting point 100 ° C.] Film (thickness: 50 μm) (15) CPP: non-stretched polypropylene film (thickness: 50 μm) [Pyrene film-CT manufactured by Toyobo Co., Ltd.] (16) LLDPE: Linear low-density polyethylene film ( (17) EVOH: ethylene / vinyl alcohol copolymer (15 μm) (18) KPVA: polyvinylidene chloride-coated polyvinyl alcohol (15 μm)

[0049]

According to the present invention, it is possible to prevent discoloration of the miso during the distribution process of the packaged product, and to prevent dissipation and transfer of aroma components through the packaging material. , Foaming and thermal discoloration of the miso in the vicinity of the sealing portion in the packaging process can be suppressed, and the transparency is excellent and the freshness of the miso can be sufficiently appealed,
Provided is a laminated film for miso packaging which has no problem of generation of chlorine gas.

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Hideaki Tanaka 18-13 Kamitamari, Tamari-mura, Niiji-gun, Ibaraki Pref.Resin Processing Technology Center, Kureha Chemical Industry Co., Ltd. (72) Inventor Tomoaki Sato 18-13 Kamitamari Kureha Chemical Industry Co., Ltd. Resin Processing Technology Center

Claims (2)

[Claims] 1. A group comprising a poly (meth) acrylic acid-based polymer, polyvinyl alcohol and a saccharide on at least one surface of a base material layer (A) formed of a thermoplastic resin having a melting point or a Vicat softening point of 180 ° C. or higher. A gas barrier resin layer (B) formed by heat-treating a film formed from a mixture with at least one selected from the group consisting of:
A laminated film for miso packaging, comprising: a laminated film having a sealing resin layer (C) made of a thermoplastic resin having a melting point of 110 ° C. or less on any one surface. 2. The laminated film comprises a sealing resin layer (C).
An outer layer (D) made of a thermoplastic resin having a higher melting point than the thermoplastic resin forming the sealing resin layer on the surface on the side opposite to
The laminated film for miso packaging according to claim 1, further comprising: