JP2006280335A - Method for preservation of article containing vinegar - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for the stable preservation of an article containing vinegar without losing the flavor of vinegar. <P>SOLUTION: A vinegar-containing article is preserved by sealing in a container made of a gas-barrier laminated material containing at least one layer of a cured epoxy resin containing ≥40 wt.% xylylenediamine skeleton structure. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a vinegar-containing article, and relates to a storage method excellent in aroma retention and oxygen barrier properties.

  Vinegar is usually made from cereals, hydrolyzed after brewing and subjected to alcoholic fermentation to convert sugar to alcohol, then seeded vinegar is added to perform acetic acid fermentation, and alcohol is converted to acetic acid to produce vinegar. Is always. The vinegar produced in this way is a seasoning that exhibits acidity and is intended for chemical action on cooking, that is, for bactericidal action or antiseptic effect by acid. For vegetables, it is used for color conservation, and recently, moromi vinegar and black vinegar containing amino acids and citric acid have many performances such as fatigue recovery and lifestyle-related diseases. It is popular as a health food. Similarly, “rice vinegar” and “oligovinegar” also contain amino acids and citric acid, and these drinking vinegars are widely used as “healthy vinegar” as soft drinks.

  In this way, vinegar is widely used in many foods, but since acetic acid, the main ingredient of vinegar, has a unique odor, vinegar-containing foods do not leak vinegar aroma into their packaging materials. Therefore, it is necessary to impart a fragrance retention property to prevent the deterioration of food due to oxygen gas by imparting an oxygen barrier property. In order to impart fragrance retention and oxygen barrier properties to such a package, conventionally lamination of aluminum foil, lamination of polyvinylidene chloride film, lamination of polyvinyl alcohol coat film and ethylene-vinyl alcohol copolymer (EVOH), Techniques such as laminating films deposited with inorganic oxides are used.

  However, aluminum foil is excellent in the storage stability of various gases, but not only cannot the product be put on a metal detector after packaging, but also has the disadvantage that aluminum residues remain during incineration. PVDC) and polyvinyl alcohol (PVA) coated films, films using ethylene-vinyl alcohol copolymer (EVOH) have good barrier properties for various gases, but the aroma retention is not practically sufficient. There is a problem that the barrier property under high humidity is inferior in the PVA coated film, and there is a concern that dioxins are generated during incineration in the PVDC coated film. When a film on which an inorganic oxide is deposited is used, care must be taken for cracks in the deposited layer due to unexpected bending or the like.

  The object of the present invention is to provide a method for storing vinegar-containing articles stably and without missing the fragrance of vinegar.

  As a result of intensive studies to solve the above problems, the present inventors filled a vinegar-containing article using a laminated material laminated using a high gas barrier adhesive mainly composed of a specific epoxy resin composition. By sealing and storing, it was found that not only can the vinegar-containing article be stably stored, but also an excellent fragrance retention property of the vinegar aroma component can be obtained, and the present invention has been completed.

  That is, according to the present invention, a vinegar-containing article is sealed and stored in a container using a gas barrier laminate material including at least one layer made of a cured epoxy resin containing 40% by weight or more of the skeleton structure of the formula (1). The present invention relates to a method for preserving vinegar-containing articles.

  ADVANTAGE OF THE INVENTION According to this invention, a vinegar containing article can be preserve | saved stably, without missing the fragrance of a vinegar.

  In the present invention, the vinegar-containing article refers to various articles containing vinegar. For example, vinegar-containing foods using rice vinegar, grain vinegar, malt vinegar, oligo vinegar, fruit vinegar, apple vinegar, grape vinegar, liquid foods such as soft drinks with vinegar, sour pork, miso, salads, potato processed products Agricultural processed products such as cooked foods such as chilled side dishes, sushi, vinegared rice, pickled vinegar, vinegared items, dressing, mayonnaise and the like.

  In the preservation method of the present invention, the vinegar-containing article is sealed in a container using a gas barrier laminate material including at least one layer made of a cured epoxy resin containing 40% by weight or more of the skeleton structure of the formula (1). It is characterized by storing. Examples of the gas barrier laminate material include a gas barrier laminate film and a gas barrier laminate sheet. Examples of the container include a bag-like container in which the film is formed, a tube, a bottle, a cup in which a sheet or film is formed, and the like. Is mentioned.

  In the storage method of the present invention, the gas barrier laminate film used when sealing the vinegar-containing article with a bag-like container is at least an outer layer (base material) made of a thermoplastic resin or paper, and an adhesive made of a cured epoxy resin. A laminate film comprising a layer and a thermoplastic resin layer (sealant layer) having heat sealability is preferred. When making a bag, the base material is used on the outer surface of the bag and the sealant layer is used on the inner surface of the bag.

Examples of the base material include polyester films such as polyethylene terephthalate and polybutylene terephthalate, polyamide films such as nylon 6, nylon 6,6, and metaxylene adipamide (N-MXD6), low density polyethylene, and high density polyethylene. , Polyolefin film such as linear low density polyethylene and polypropylene, polyacrylonitrile film, poly (meth) acrylic film, polystyrene film, polycarbonate film, ethylene-vinyl alcohol copolymer (EVOH) film, polyvinyl alcohol Polyvinylidene chloride (PVDC) resin and polyvinyl alcohol resin for plastic films such as plastic films, papers such as cartons, metal foils such as aluminum and copper, and various materials used as these substrates Disperse films coated with various polymers such as saponified ethylene-vinyl acetate copolymers and acrylic resins, films deposited with various inorganic compounds such as silica, alumina, aluminum, or metals, inorganic fillers, etc. And a film provided with an oxygen scavenging function can be used. Moreover, an inorganic filler can be disperse | distributed also about the various polymers to coat. Examples of inorganic fillers include silica, alumina, mica, talc, aluminum flakes, and glass flakes. Layered silicates such as montmorillonite are preferred, and dispersion methods thereof include, for example, extrusion kneading and mixing into resin solutions. A conventionally known method such as a dispersion method can be used. Examples of methods for imparting oxygen scavenging functions include hindered phenols, vitamin C, vitamin E, organic phosphorus compounds, gallic acid, pyrogallol and other low molecular organic compounds that react with oxygen, cobalt, manganese, nickel, iron And a method of using a composition containing a transition metal compound such as copper at least in part.
The thickness of the material such as these films is practically about 10 to 300 μm, preferably about 10 to 100 μm, and in the case of a plastic film, it may be uniaxially or biaxially stretched. Various surface treatments such as flame treatment and corona discharge treatment may be performed on the surface of the film.

  A flexible polymer film is preferably used as the sealant layer, and a polyolefin film such as a polyethylene film, a polypropylene film, or an ethylene-vinyl acetate copolymer is selected in consideration of the expression of good heat sealability. Is preferred. The thickness of these films is practically about 10 to 300 μm, preferably about 10 to 100 μm, and various surface treatments such as flame treatment and corona discharge treatment may be performed on the surface of the film.

  Further, the surface of the outer layer and the inner layer of the gas barrier laminate film may be subjected to a printing process. When printing processing is performed, general printing equipment that has been used for printing on a conventional thermoplastic resin film such as a gravure printing machine, a flexographic printing machine, and an offset printing machine can be similarly applied. Also, as for the ink forming the printing layer, conventional thermoplastic resin films formed from pigments such as azo and phthalocyanine, resins such as rosin, polyamide resin and polyurethane, solvents such as methanol, ethyl acetate and methyl ethyl ketone The inks that have been used for printing layers on can be applied as well.

  In the present invention, the adhesive application surface may form a primer (medium) layer. In that case, as long as it has adhesiveness with the substrate, primers of various chemical structures can be used for both one-part and two-part systems, preferably methanol such as methanol suitably used as the main solvent of the adhesive A polyester primer with low alcohol permeability is practical. The thickness of the primer layer is 0.01 to 20 μm, preferably 0.1 to 5 μm. When the thickness is less than 0.01 μm, sufficient adhesion is hardly exhibited, while when the thickness exceeds 20 μm, it is difficult to form a primer layer having a uniform thickness.

  The gas barrier laminated film in the storage method of the present invention is obtained by laminating an outer layer made of a thermoplastic resin, a thermoplastic resin layer having heat sealing properties, and the like. At the time of laminating each layer constituting the laminated film, at least one layer is formed. These adhesive layers are bonded with a laminating adhesive mainly composed of an epoxy resin composition comprising an epoxy resin and an epoxy resin curing agent. About adhesive layers other than the adhesive layer which uses this adhesive agent for lamination | stacking, other adhesive agents, such as a polyurethane-type adhesive agent, may be used, and resin may be welded.

  In the storage method of the present invention, the gas barrier laminate film or sheet used when sealing a vinegar-containing article with a sheet or film molded article is at least one layer comprising the cured epoxy resin. Well, the other layers can be selected from various materials used as the substrate. For example, a three-layer structure composed of polyolefin / epoxy resin cured product / polyolefin using an epoxy resin cured product as an adhesive layer is exemplified, but the invention is not limited thereto.

In the storage method of the present invention, the cured epoxy resin is obtained by curing an epoxy resin composition comprising an epoxy resin and an epoxy resin curing agent, and the skeleton structure of the above formula (1) is contained in the cured epoxy resin. Is contained in an amount of 40% by weight or more, preferably 45% by weight or more, more preferably 50% by weight or more. When the skeleton structure of the formula (1) is contained at a high level in the cured epoxy resin, a high gas barrier property is exhibited. This high gas barrier property can prevent oxygen contamination from the outside of the container and maintain the stability of the vinegar-containing article, and can prevent the fragrance component from escaping. According to the present invention, it is also possible to obtain an epoxy resin cured product having an oxygen barrier property of an oxygen permeability coefficient of 1.0 ml · mm / m ² · day · MPa (23 ° C., 60% RH) or less. Below, the epoxy resin and epoxy resin hardening | curing agent which are the main components of an epoxy resin composition are demonstrated.

  The epoxy resin in the present invention may be any of an aliphatic compound, an alicyclic compound, an aromatic compound, or a heterocyclic compound. However, in consideration of the expression of high gas barrier properties, the aromatic moiety is located in the molecule. Is preferable, and an epoxy resin including the skeleton structure of the above formula (1) in the molecule is more preferable. Specifically, an epoxy resin having a glycidylamine moiety derived from metaxylylenediamine, an epoxy resin having a glycidylamine moiety derived from 1,3-bis (aminomethyl) cyclohexane, and a glycidylamine derived from diaminodiphenylmethane An epoxy resin having a glycidylamine moiety and / or a glycidyl ether moiety derived from paraaminophenol, an epoxy resin having a glycidyl ether moiety derived from bisphenol A, and a glycidyl ether moiety derived from bisphenol F Epoxy resin having glycidyl ether moiety derived from phenol novolac, epoxy resin having glycidyl ether moiety derived from resorcinol Fats can be used, but among them, epoxy resin having glycidylamine moiety derived from metaxylylenediamine, epoxy resin having glycidylamine moiety derived from 1,3-bis (aminomethyl) cyclohexane, derived from bisphenol F Preferred are epoxy resins having a glycidyl ether moiety and epoxy resins having a glycidyl ether moiety derived from resorcinol.

  Further, it is more preferable to use an epoxy resin having a glycidyl ether moiety derived from bisphenol F or an epoxy resin having a glycidyl amine moiety derived from metaxylylenediamine as a main component, and derived from metaxylylenediamine. It is particularly preferable to use an epoxy resin having a glycidylamine moiety as a main component.

  Moreover, in order to improve various performances such as flexibility, impact resistance, and moist heat resistance, the above-mentioned various epoxy resins can be mixed and used at an appropriate ratio.

The epoxy resin in the present invention is obtained by reaction of various alcohols, phenols and amines with epihalohydrin. For example, an epoxy resin having a glycidylamine moiety derived from metaxylylenediamine can be obtained by adding epichlorohydrin to metaxylylenediamine.
Here, the glycidylamine moiety comprises a mono-, di-, tri- and / or tetra-glycidylamine moiety that can replace the four hydrogen atoms of the diamine in xylylenediamine. The ratio of mono-, di-, tri- and / or tetra-glycidylamine moieties can be varied by changing the reaction ratio of metaxylylenediamine to epichlorohydrin. For example, an epoxy resin mainly having a tetraglycidylamine moiety can be obtained by addition reaction of about 4 times mole of epichlorohydrin to metaxylylenediamine.

The epoxy resin is an excess of epihalohydrin with respect to various alcohols, phenols and amines in the presence of an alkali such as sodium hydroxide, 20 to 140 ° C., preferably 50 to 120 ° C. in the case of alcohols and phenols, amine In the case of a kind, it is synthesized by reacting at a temperature of 20 to 70 ° C. and separating the produced alkali halide.
The number average molecular weight of the produced epoxy resin varies depending on the molar ratio of epihalohydrin to various alcohols, phenols and amines, but is about 80 to 4000, preferably about 200 to 1000, preferably about 200 to 500. It is more preferable.

The epoxy resin curing agent in the present invention may be any of an aliphatic compound, an alicyclic compound, an aromatic compound, or a heterocyclic compound, such as polyamines, phenols, acid anhydrides, or carboxylic acids. Any commonly used epoxy resin curing agent can be used. These epoxy resin curing agents can be selected according to the use application of the laminate film and the required performance in the application.
Specifically, polyamines include aliphatic amines such as ethylenediamine, diethylenetriamine, triethylenetetramine and tetraethylenepentamine, aliphatic amines having an aromatic ring such as metaxylylenediamine and paraxylylenediamine, 1,3- Examples include alicyclic amines such as bis (aminomethyl) cyclohexane, isophoronediamine, norbornanediamine, and aromatic amines such as diaminodiphenylmethane and metaphenylenediamine.
Also, reaction products with epoxy resins or monoglycidyl compounds made from these polyamines, reaction products with alkylene oxides having 2 to 4 carbon atoms, reaction products with epichlorohydrin, these polyamines A reaction product with a polyfunctional compound having at least one acyl group capable of forming an amide group site by reaction with, an oligomer with an amide group site formed by reaction with these polyamines A reaction product of a polyfunctional compound having at least one acyl group and a monovalent carboxylic acid and / or a derivative thereof can be used.

Examples of phenols include multi-substituent monomers such as catechol, resorcinol and hydroquinone, and resole type phenol resins.
Acid anhydrides or carboxylic acids include aliphatic acid anhydrides such as dodecenyl succinic anhydride and polyadipic anhydride, and alicyclic acid anhydrides such as (methyl) tetrahydrophthalic anhydride and (methyl) hexahydrophthalic anhydride. Aromatic acid anhydrides such as phthalic anhydride, trimellitic anhydride, pyromellitic anhydride, and carboxylic acids thereof can be used.

In consideration of the expression of high gas barrier properties, an epoxy resin curing agent containing an aromatic moiety in the molecule is preferred, and an epoxy resin curing agent containing the skeleton structure of the above formula (1) in the molecule is more preferred.
Specifically, metaxylylenediamine or paraxylylenediamine, reaction products with epoxy resins or monoglycidyl compounds using these as raw materials, reaction products with alkylene oxides having 2 to 4 carbon atoms, epichlorohydrin Reaction products with these polyamines, reaction products with polyfunctional compounds having at least one acyl group that can form oligomers by reaction with these polyamines, and with these polyamines It is more preferable to use a reaction product of a polyfunctional compound having at least one acyl group and a monovalent carboxylic acid and / or a derivative thereof, which can form an amide group site by the reaction of preferable.

When considering high gas barrier properties and good adhesiveness, the following reaction products (A) and (B) or reactions (A), (B), and (C) are used as epoxy resin curing agents. It is particularly preferred to use the product.
(A) Metaxylylenediamine or paraxylylenediamine
(B) A polyfunctional compound having at least one acyl group capable of forming an amide group site by reaction with a polyamine to form an oligomer
(C) C1-C8 monovalent carboxylic acid and / or derivative thereof

  Examples of the polyfunctional compound having at least one acyl group that can form an amide group site by reaction with the (B) polyamine to form an oligomer include acrylic acid, methacrylic acid, maleic acid, fumaric acid, succinic acid, Carboxylic acids such as malic acid, tartaric acid, adipic acid, isophthalic acid, terephthalic acid, pyromellitic acid, trimellitic acid and their derivatives such as esters, amides, acid anhydrides, acid chlorides, etc., especially acrylic acid Methacrylic acid and derivatives thereof are preferred.

  In addition, monovalent carboxylic acids having 1 to 8 carbon atoms such as formic acid, acetic acid, propionic acid, butyric acid, lactic acid, glycolic acid, benzoic acid, and derivatives thereof such as esters, amides, acid anhydrides, acid chlorides, etc. The polyfunctional compound may be used in combination with the starting polyamine. The amide group site introduced by the reaction has a high cohesive force, and the presence of the amide group site in a high proportion in the epoxy resin curing agent provides higher oxygen barrier properties and better adhesive strength.

  The reaction molar ratio of (A) and (B) or (A), (B), and (C) is the reactive functionality contained in (B) with respect to the number of amino groups contained in (A). The ratio of the number of groups, or the ratio of the total number of reactive functional groups contained in (B) and (C) to the number of amino groups contained in (A) is in the range of 0.3 to 0.97 Is preferred. When the ratio is less than 0.3, a sufficient amount of amide groups are not generated in the epoxy resin curing agent, and a high level of gas barrier properties and adhesiveness are not exhibited. Moreover, the ratio of the volatile molecule which remains in the epoxy resin curing agent is increased, which causes odor generation from the obtained cured product. Moreover, since the ratio of the hydroxyl group produced | generated by reaction of an epoxy group and an amino group in the hardening reaction material becomes high, it becomes a factor by which oxygen barrier property in a high humidity environment falls remarkably. On the other hand, in the range higher than 0.97, the amount of amino groups reacting with the epoxy resin is reduced, and excellent impact resistance and heat resistance are not exhibited, and the solubility in various organic solvents or water is lowered. When particularly considering the high gas barrier property, high adhesion, suppression of odor generation, and high oxygen barrier property in a high humidity environment of the obtained cured product, the molar ratio of the polyfunctional compound to the polyamine component is 0.6. A range of ˜0.97 is more preferable. In consideration of the expression of a higher level of adhesiveness, it is preferable that the epoxy resin curing agent in the present invention contains at least 6% by weight of an amide group based on the total weight of the curing agent.

  The laminate film produced using the adhesive composed of the epoxy resin composition preferably has a laminate strength of 30 g / 15 mm or more immediately after lamination (before aging) at a peeling speed of 300 mm / min, 40 g / 15 mm. More preferably, it is 50 g / 15 mm or more. When the laminate strength is not sufficient, problems such as tunneling of the laminate film and winding deviation at the time of winding the film occur.

In consideration of the expression of high shear strength, for example, at least 1 that can form an amide group site by forming an amide group site by reacting an epoxy resin curing agent such as metaxylylenediamine or paraxylylenediamine with the polyamine. The reaction ratio of the reaction product with the polyfunctional compound having one acyl group is 0.6 to 0.97, preferably 0.8 to 0.97, particularly preferably molar ratio of the polyfunctional compound to the polyamine component. Is preferably in the range of 0.85 to 0.97, and it is preferable to use an epoxy resin curing agent in which the average molecular weight of the oligomer as the reaction product is increased.
A more preferred epoxy resin curing agent is a reaction product of metaxylylenediamine and acrylic acid, methacrylic acid and / or derivatives thereof. Here, the reaction molar ratio of acrylic acid, methacrylic acid and / or derivatives thereof to metaxylylenediamine is preferably in the range of 0.8 to 0.97.

About the compounding ratio of the epoxy resin and the epoxy resin curing agent which are the main components of the adhesive in the present invention, generally in the standard compounding range when producing an epoxy resin cured product by reaction of the epoxy resin and the epoxy resin curing agent. It may be. Specifically, the ratio of the number of active hydrogens in the epoxy resin curing agent to the number of epoxy groups in the epoxy resin is in the range of 0.5 to 5.0. If the range is less than 0.5, the remaining unreacted epoxy group causes the gas barrier property of the resulting cured product to decrease, and if it is greater than 5.0, the remaining unreacted amino group results in the resulting cured product. It becomes a cause of lowering the heat and heat resistance. In the case where gas barrier properties and wet heat resistance of the obtained cured product are particularly taken into consideration, the range of 0.8 to 3.0 is more preferable, and the range of 0.8 to 2.0 is particularly preferable.
In addition, when considering the expression of a high oxygen barrier property in a high humidity environment of the resulting cured product, the ratio of the number of active hydrogens in the epoxy resin curing agent to the number of epoxy groups in the epoxy resin is 0.8. A range of ˜1.6 is preferred.

  In the adhesive according to the present invention, if necessary, a thermosetting resin composition such as a polyurethane resin composition, a polyacrylic resin composition, or a polyurea resin composition may be used as long as the effects of the present invention are not impaired. You may mix.

  The adhesive in the present invention may contain a wetting agent such as silicon or an acrylic compound, if necessary, to help wet the surface of various materials during application. Suitable wetting agents include BYK331, BYK333, BYK347, BYK348, BYK354, BYK380, BYK381 available from Big Chemie. When adding these, the range of 0.01 weight%-2.0 weight% is preferable on the basis of the total weight of an epoxy resin composition.

  In the present invention, a tackifier such as a xylene resin, a terpene resin, a phenol resin, or a rosin resin may be added as necessary in order to improve the adhesiveness to various materials immediately after coating. When adding these, the range of 0.01 weight%-5.0 weight% is preferable on the basis of the total weight of an epoxy resin composition.

Moreover, in order to improve various performances such as gas barrier properties, impact resistance, and heat resistance of the adhesive layer formed by the adhesive in the present invention, silica, alumina, mica, talc, aluminum flakes, Inorganic fillers such as glass flakes may be added.
In consideration of the transparency of the film, it is preferable that such an inorganic filler has a flat plate shape. When adding these, the range of 0.01 weight%-10.0 weight% is preferable on the basis of the total weight of an epoxy resin composition.

  Moreover, you may add the compound etc. which have an oxygen capture | acquisition function to the adhesive agent in this invention as needed. Examples of the compound having an oxygen scavenging function include low molecular organic compounds that react with oxygen such as hindered phenols, vitamin C, vitamin E, organic phosphorus compounds, gallic acid, pyrogallol, cobalt, manganese, nickel, iron, Examples include transition metal compounds such as copper.

  Furthermore, in order to improve the adhesiveness of the adhesive layer formed by the adhesive in the present invention, a coupling agent such as a silane coupling agent or a titanium coupling agent may be added to the adhesive. When adding these, the range of 0.01 weight%-5.0 weight% is preferable on the basis of the total weight of an epoxy resin composition.

  The adhesive in the present invention is characterized by having high gas barrier properties in addition to suitable adhesive performance, and exhibits high gas barrier properties in a wide range from low humidity conditions to high humidity conditions. From this, the laminate film using the adhesive in the present invention is a PVDC coat layer, a polyvinyl alcohol (PVA) coat layer, an ethylene-vinyl alcohol copolymer (EVOH) film layer, a metaxylylene adipamide film layer, A very high level of gas barrier properties is exhibited without using a commonly used gas barrier material such as an inorganic vapor deposition film layer on which alumina or silica is vapor-deposited. Furthermore, the gas barrier properties of the resulting film can be significantly improved by using these conventional gas barrier materials and sealant materials together as an adhesive.

  Gas barriers such as ethylene-vinyl alcohol copolymer (EVOH) film, polyvinyl alcohol film, polyvinyl alcohol coated film, polyvinyl alcohol coated film in which inorganic filler is dispersed, metaxylene adipamide (N-MXD6) film, etc. The gas barrier film has a drawback that its gas barrier property is lowered under high humidity conditions. However, when the adhesive film of the present invention is used to produce a laminate film containing these gas barrier films, this disadvantage is solved. be able to.

  Furthermore, since the cured epoxy resin in the present invention is excellent in toughness and heat-and-moisture resistance, a gas barrier laminate film excellent in impact resistance, boiling resistance, retort resistance and the like can be obtained.

  In the case of laminating various film materials using the adhesive in the present invention, a known laminating method such as dry lamination, non-solvent laminating, extrusion laminating, etc. can be used. Is preferred.

  When the adhesive in the present invention is applied to various materials and laminated, it is carried out at a concentration and temperature of an epoxy resin composition sufficient to obtain an epoxy resin cured product that becomes an adhesive layer. It can vary depending on the choice of materials and lamination methods. That is, the concentration of the epoxy resin composition is about 5% by weight using a certain type of appropriate organic solvent and / or water from the case where no solvent is used, depending on the type and molar ratio of the selected material, the lamination method, and the like. Various states can be taken up to the case where the coating liquid is prepared by diluting to the composition concentration. As the organic solvent to be used, any solvent having solubility with an adhesive can be used. For example, water-insoluble solvents such as toluene, xylene, methyl acetate, ethyl acetate, butyl acetate, acetone, methyl ethyl ketone, 2-methoxyethanol, 2-ethoxyethanol, 2-propoxyethanol, 2-butoxyethanol, 1-methoxy-2 Glycol ethers such as 1-propanol, 1-ethoxy-2-propanol, 1-propoxy-2-propanol, alcohols such as methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, N, Examples include aprotic polar solvents such as N-dimethylformamide, N, N-dimethylacetamide, dimethyl sulfoxide, and N-methylpyrrolidone.

  The adhesive (coating solution) diluted with a solvent can be diluted at a concentration such that the Zahn cup (No. 3) viscosity is in the range of 5 to 30 seconds (25 ° C.). If the Zahn cup (No. 3) viscosity is less than 5 seconds, the adhesive is not sufficiently applied to the object to be coated, which may cause roll contamination. On the other hand, when the Zahn cup (No. 3) viscosity exceeds 30 seconds, the adhesive is not sufficiently transferred to the roll, and it becomes difficult to form a uniform adhesive layer. For example, in dry lamination, the Zahn cup (No. 3) viscosity is preferably 10 to 20 seconds (25 ° C.) during use.

  In order to suppress foaming of the coating liquid when preparing the coating liquid in the present invention, an antifoaming agent such as silicon or an acrylic compound may be added to the coating liquid. Suitable antifoaming agents include BYK019, BYK052, BYK067N, BYK070, BYK080 and the like available from Big Chemie, with BYK019 being particularly preferred. Moreover, when adding these antifoamers, the range of 0.01 weight%-3.0 weight% is preferable on the basis of the total weight of the epoxy resin composition in a coating liquid, 0.02 weight%-2 More preferred is 0.0% by weight.

  When a solvent is used, the solvent drying temperature after application of the adhesive may vary from 20 ° C. to 140 ° C., but it is close to the boiling point of the solvent and affects the object to be coated. No temperature is desirable. When the drying temperature is less than 20 ° C., the solvent remains in the laminate film, which causes poor adhesion and odor. When the drying temperature exceeds 140 ° C., it becomes difficult to obtain a laminate film having a good appearance due to softening of the polymer film. For example, when apply | coating an adhesive agent to a stretched polypropylene film, 40 to 120 degreeC is desirable.

  Any of commonly used coating formats such as roll coating, spray coating, air knife coating, dipping, and brush coating can be used as the coating format for applying the adhesive. Roll coating or spray coating is preferred. For example, the same roll coat or spray technique and equipment as when a polyurethane adhesive component is applied to a polymer film and laminated can be applied.

Next, specific operations in each laminating method will be described. In the case of the dry laminating method, the coating liquid is applied to a film material including a substrate by a roll such as a gravure roll, and then the solvent is dried and a new film material is immediately bonded to the surface by a nip roll to form a laminated film. Obtainable. The solvent for preparing the adhesive is preferably a solvent having good solubility and a relatively low boiling point and containing an alcohol having 3 or less carbon atoms. The group consisting of methanol, ethanol, isopropanol, and n-propanol The solvent which has as a main component 1 or more types chosen from is illustrated. In addition, it is a mixed solution in which a solvent having an ester group, ketone group, or aldehyde group functional group that has the effect of delaying the reaction between the epoxy resin and the polyamine and suppressing the increase in the viscosity of the adhesive to prolong the working time. Preferably there is. As a mixed liquid in which a solvent having any functional group of an ester group, a ketone group, or an aldehyde group is mixed, it is selected from the group consisting of methyl acetate, ethyl acetate, acetone, methyl ethyl ketone, acetaldehyde, and propionaldehyde having a relatively low boiling point. The liquid mixture which mixed 1 or more types is illustrated. In order to obtain a film with a small amount of solvent remaining in the obtained laminate film, the content of the solvent having any functional group of ester group, ketone group, and aldehyde group is preferably 20% by weight or less in the total solvent. Here, if there is a large amount of solvent remaining in the laminate film, it may cause a bad odor. Therefore, the amount of the remaining solvent is practically 7 mg / m ² or less, and if it is more than 7 mg / m ² , a strange odor is felt from the film. Cause. Preferably 5 mg / ^{m 2} or less in the case of strictly control the odor of the film, 3 mg / ^{m 2} or less is particularly preferred.

  In the dry laminating method, the adhesive can also be applied to the sealant layer, and applied to a polyolefin film such as a polyethylene film, a polypropylene film or an ethylene-vinyl acetate copolymer, dried, and then stretched polypropylene or a polyamide film. By laminating a base material such as a polyethylene terephthalate film, a laminate film can be produced.

  In the case of bonding by nip roll, the nip roll can be heated and bonded to 20 ° C. to 120 ° C., but 40 to 100 ° C. is desirable.

  In this case, it is desirable to complete the curing reaction by performing aging at 20 ° C. to 60 ° C. for a certain time as necessary after lamination. By performing aging for a certain period of time, a cured epoxy resin is formed with a sufficient reaction rate, and high gas barrier properties are exhibited. When the aging is 20 ° C. or less or without aging, the reaction rate of the epoxy resin composition is low, and sufficient gas barrier properties and adhesive strength cannot be obtained. Also, aging at 60 ° C. or higher can cause problems such as polymer film blocking and additive elution.

  In the case of the non-solvent laminating method, a roll such as a gravure roll in which the adhesive in the present invention, which has been heated to about 40 ° C. to 100 ° C. in advance on a film material containing a substrate, is heated to 40 ° C. to 120 ° C. After the coating, a laminate film can be obtained by pasting a new film material on the surface immediately after coating. In this case as well, as in the case of the dry laminating method, it is desirable to perform aging for a predetermined time after the lamination as necessary.

In the case of the extrusion laminating method, the epoxy resin and the epoxy resin curing agent, which are the main components of the adhesive in the present invention, are diluted with an organic solvent and / or water as an adhesive aid (anchor coating agent) for the film material including the base material. The solution is applied by a roll such as a gravure roll, and after drying and curing the solvent at 20 ° C. to 140 ° C., a laminate film can be obtained by laminating the polymer material melted by an extruder. The polymer material to be melted is preferably a polyolefin resin such as a low density polyethylene resin, a linear low density polyethylene resin, or an ethylene-vinyl acetate copolymer resin.
These laminating methods and other laminating methods that can be generally used can be combined as necessary, and the layer structure of the laminating film can be changed depending on the application and form.

  The thickness of the adhesive layer after applying, drying, bonding and heat-treating the adhesive in the present invention to various materials is 0.1 to 100 μm, preferably 0.5 to 10 μm. If the thickness is less than 0.1 μm, sufficient gas barrier properties and adhesiveness are hardly exhibited. On the other hand, if the thickness exceeds 100 μm, it is difficult to form an adhesive layer having a uniform thickness.

  The laminate film has excellent laminate strength. The laminate strength at a peeling speed of 300 mm / min after the heat treatment varies depending on the material of the base material and the sealant layer. For example, when the base material is stretched polypropylene, 80 g / 15 mm or more is preferable, and 100 g / 15 mm or more is more preferable. It is preferably 120 g / 15 mm or more. On the other hand, when the base material is stretched nylon or polyethylene terephthalate, if the sealant layer is low density polyethylene, it is preferably 600 g / 15 mm or more, more preferably 700 g / 15 mm or more, and particularly preferably 800 g / 15 mm or more. If is unstretched polypropylene, it is preferably 300 g / 15 mm or more, more preferably 400 g / 15 mm or more, and particularly preferably 500 g / 15 mm or more.

  In the preservation of vinegar-containing articles using the gas barrier laminate material produced using the adhesive in the present invention, the layer structure can be changed according to the usage form. That is, the laminate film of the present invention can be used as a gas barrier laminate material for preserving vinegar-containing articles as it is, and an oxygen absorbing layer, a thermoplastic resin film layer, a paper layer, a metal foil layer, etc. can be used as needed. The laminate film in the present invention can be further laminated. Under the present circumstances, you may laminate using the adhesive agent in this invention, and you may laminate using another adhesive agent and an anchor coat agent.

  A bag-like container for storing vinegar-containing articles manufactured using the gas barrier laminate material will be described. The bag-like container is manufactured by using the gas barrier laminate material and superimposing the surfaces of the heat-sealable resin layer facing each other, and then heat-sealing the peripheral end portion to form a seal portion. be able to. As the bag making method, for example, the gas barrier laminate material is folded or overlapped so that the inner layer faces each other, and the peripheral end thereof is, for example, a side seal type, a two-side seal type, or a three-side seal. There is a method of heat-sealing in the form of heat-sealing such as mold, four-side seal type, envelope sticker seal type, palm seal sticker type (pillow seal type), pleated seal type, flat bottom seal type, square bottom seal type, gusset type, etc. Can be mentioned. The bag-like container can take various forms depending on the use environment and use form. In addition, for example, a self-supporting packaging bag (standing pouch) is also possible. As a heat sealing method, for example, a known method such as a bar seal, a rotary roll seal, a belt seal, an impulse seal, a high frequency seal, or an ultrasonic seal can be used.

  A vinegar-containing article can be stored by filling the bag-like container with the vinegar-containing article from the opening and then heat-sealing the opening.

  Examples of the present invention are introduced below, but the present invention is not limited to these examples.

<Epoxy resin curing agent a>
A reaction vessel was charged with 1 mole of metaxylylenediamine. The temperature was raised to 60 ° C. under a nitrogen stream, and 0.93 mol of methyl acrylate was added dropwise over 1 hour. After completion of the dropwise addition, the mixture was stirred at 120 ° C. for 1 hour, and further heated to 160 ° C. in 3 hours while distilling off generated methanol. The mixture was cooled to 100 ° C., and a predetermined amount of methanol was added so that the solid content concentration became 70% by weight to obtain an epoxy resin curing agent a. The content of amide groups in the epoxy resin curing agent a was 21% by weight.

In addition, evaluation methods such as oxygen permeability and laminate strength are as follows.
<Oxygen permeability (ml / m ² · day · MPa)>
The oxygen transmission rate of the laminate film was measured under conditions of 23 ° C. and 60% relative humidity using an oxygen transmission rate measurement device (OX-TRAN 10 / 50A, manufactured by Modern Control).
<Lamination strength (g / 15mm)>
Using the method specified in JISK-6854, the laminate strength of the laminate film was measured by a T-type peel test at a peel rate of 300 mm / min.
<Incense retention test>
A laminate film of 5 cm × 5 cm size was prepared, 2 ml of rice vinegar was sealed in this bag, this sealed bag was sealed in a glass container, and stored for 1 to 14 days at a temperature of 23 ° C. and a relative humidity of 60%. . Each time, the presence or absence of odor leakage was confirmed by a sensory test. The case in which the fragrance retention of the contents was maintained was rated as ◯, the case where slight odor leakage was confirmed was evaluated as △, and the case where obvious odor leakage was confirmed was rated as ×.

<Laminated film A>
Methanol / ethyl acetate containing 9 parts by weight of epoxy resin having a glycidylamine moiety derived from metaxylylenediamine (Mitsubishi Gas Chemical Co., Ltd .; TETRAD-X) and 146 parts by weight of epoxy resin curing agent a = 9 / One solution (solid content concentration: 35% by weight) was prepared, and 0.4 parts by weight of an acrylic wetting agent (BIC Chemie; BYK381) was added thereto and stirred well to obtain a coating solution.
This coating solution was applied to a 20 μm-thick stretched polypropylene film using a bar coater No. 6 (coating amount: 3.5 g / m ² (solid content)), dried at 85 ° C. for 10 seconds, A laminated film A was obtained by laminating a 40 μm linear low density polyethylene film with a nip roll and aging at 40 ° C. for 4 days. The initial adhesive strength was 70 g / 15 mm, and the content of the skeleton structure of the formula (1) in the adhesive layer (cured epoxy resin) was 62.0% by weight.

<Laminated film B>
A laminated film B was obtained in the same manner as the laminated film A except that a stretched nylon film having a thickness of 15 μm was used instead of the stretched polypropylene film having a thickness of 20 μm. The initial adhesive strength was 70 g / 15 mm.

<Laminated film C>
Methanol / ethyl acetate containing 9 parts by weight of epoxy resin having a glycidylamine moiety derived from metaxylylenediamine (Mitsubishi Gas Chemical Co., Ltd .; TETRAD-X) and 146 parts by weight of epoxy resin curing agent a = 9 / 1 solution (solid content concentration: 35% by weight) was prepared, and 0.4 parts by weight of acrylic wetting agent (by Kick Chemie; BYK381) was added thereto and stirred well, and the Zahn cup (No. 3) viscosity was added. An adhesive of 14 seconds (25 ° C.) was obtained.
Polyester primer (AD-76H5 / CAT-10L manufactured by Toyo Morton Co., Ltd.) is diluted with a mixed solvent of toluene / methyl ethyl ketone (50 parts by weight / 50 parts by weight) to a solid content concentration of 15% by weight, and stretched with a thickness of 15 μm 6 -Nylon film (Harden N1102 manufactured by Toyobo Co., Ltd.) was coated using a bar coater No. 4 (coating amount: 1.0 g / m ² (solid content)) and dried at 85 ° C. for 10 seconds. The coating solution used in the laminated film A was applied using a bar coater No. 6 (coating amount: 3.5 g / m ² (solid content)), dried at 85 ° C. for 10 seconds, and then 40 μm in thickness. The linear low density polyethylene film was laminated by a nip roll and aged at 40 ° C. for 4 days to obtain a laminated film C. The initial adhesive strength was 70 g / 15 mm, and the content of the skeleton structure of the formula (1) in the adhesive layer (cured epoxy resin) was 62.0% by weight.

<Laminated film D>
An ethyl acetate solution containing 50 parts by weight of a main agent made of polyurethane resin (manufactured by Toyo Morton Co., Ltd .; TM-329) and 50 parts by weight of a curing agent made of polyisocyanate resin (manufactured by Toyo Morton Co., Ltd .; CAT-8B) ( (Solid content concentration: 25% by weight) was prepared and stirred well to obtain a coating solution. Using this coating solution, a 20 μm-thick polyvinylidene chloride-coated stretched polypropylene film (Senecy KOP # 6000, manufactured by Daicel Chemical Industries, Ltd.) is used in place of the 20 μm-thick stretched polypropylene film, and bar coater No. 5 is used. The laminated film D was obtained in the same manner as the laminated film A, except that it was coated (coating amount: 2.0 g / m ² (solid content)).

<Laminated film E>
A polyvinyl alcohol-coated stretched polypropylene film (AOP-BH, manufactured by Tosero Co., Ltd.) having a thickness of 20 μm was used instead of a 20 μm-thick polyvinylidene chloride-coated stretched polypropylene film (Senecy KOP # 6000, manufactured by Daicel Chemical Industries, Ltd.). A laminated film E was obtained in the same manner as the laminated film D.

<Example 1>
Two laminated films A are prepared, the surfaces of the linear low-density polyethylene film are opposed to each other, and the ends around the outer periphery are heat-sealed in three directions to form a seal portion. A side-seal type packaging bag was produced. 2 ml of rice vinegar was sealed from the opening in the produced three-side sealed packaging bag, and then the bag was sealed in a glass container. The results are shown in Table 1.

<Example 2>
Instead of using the laminated film A, the same procedure as in Example 1 was performed except that the laminated film B was used. The results are shown in Table 1.

<Example 3>
Instead of using the laminated film A, the same procedure as in Example 1 was performed except that the laminated film C was used. The results are shown in Table 1.

<Comparative Example 1>
Instead of using the laminated film A, the same procedure as in Example 1 was performed except that the laminated film D was used. The results are shown in Table 1.

<Comparative example 2>
Instead of using the laminated film A, the same procedure as in Example 1 was performed except that the laminated film E was used. The results are shown in Table 1.

Claims (3)

(1) A vinegar-containing article is sealed and stored in a container using a gas barrier laminate material including at least one layer composed of an epoxy resin cured product containing 40% by weight or more of the skeleton structure of the formula (1). A method for preserving vinegar-containing articles.

The method for preserving a vinegar-containing article according to claim 1, wherein the cured epoxy resin has an oxygen barrier property of an oxygen permeability coefficient of 1.0 ml · mm / m ² · day · MPa (23 ° C., 60% RH) or less. The container is a bag made of a gas barrier laminated film including at least an outer layer made of a thermoplastic resin or paper, an inner layer made of a thermoplastic resin having heat sealability, and an adhesive layer made of a cured epoxy resin. The preservation | save method of the vinegar containing article | item of Claim 1.