Microwave-induced heat release composition, microwave-induced heat release layer, microwave-induced heat release film, microwave-induced heat release package, and method for preparing microwave-induced heat release film

Abstract

A microwave-induced exothermic composition includes an electrically conductive polymer and a resin. The resin is at least one selected from the group consisting of a styrene-butadiene copolymer, an acrylonitrile-butadiene copolymer, a vinyl acetate resin, and a silicone resin.

Description

TECHNICAL FIELD

[0001] The disclosure herein relates generally to a microwave-induced exothermic composition, a microwave-induced exothermic layer, a microwave-induced exothermic film, a microwave-induced exothermic package, and a method of producing a microwave-induced exothermic film. BACKGROUND

[0002] A package for containing food to be heated and cooked with a microwave oven, in which the food is sealed inside the package. Therefore, a microwave-induced exothermic composition is used as a microwave-induced exothermic material that generates heat upon microwave irradiation and is placed at a heat-sealed portion or a printed portion of the package. The use of the microwave-induced exothermic material helps release water vapor generated by heating the food from the package to impart water vapor permeability to the package.

[0003] As a microwave-induced exothermic composition for a package, for example, it is disclosed that a microwave-induced exothermic composition including a conductive organic compound, a dopant, and a resin is used in a coating layer forming a microwave-induced exothermic package film (see, for example, PTL 1).

[0004] A package having an exothermic printed layer formed by using a microwave-induced exothermic composition available in the related art has a problem such that when the exothermic printed layer comes into contact with another object or an impact is applied to the exothermic printed layer during production, the exothermic printed layer thus generated is easily peeled off from the package. If the exothermic printed layer is peeled off from the package, the water vapor permeability of the package can be impaired, or the food inside the package can be contaminated by the peeled exothermic printed layer. For example, the exothermic printed layer can be peeled off from the package when the exothermic printed layer comes into contact with a carton or another package for transportation, when a jam occurs inside a package roll, or when an impact is applied to the exothermic printed layer while forming an opening for releasing water vapor.

[0005] In addition, a package including an exothermic printed layer formed by a microwave-induced exothermic composition available in the related art has a property such that the exothermic printed layer is more easily peeled off from the package, particularly when the exothermic printed layer comes into contact with water. For example, the exothermic printed layer can be peeled off from the package due to water vapor generated by microwave-heated food, moisture in a refrigerator storage environment, or moisture generated by condensation.

[0006] One embodiment of the present disclosure aims to provide a microwave-induced exothermic composition that achieves excellent adhesion to a substrate and excellent water resistance, as well as high water vapor permeability, when the microwave-induced exothermic composition is used in a microwave-induced exothermic film or a microwave-induced exothermic package.

[0007] LIST OF CITATIONS PATENT LITERATURE PTL 1: Japanese Patent No. 6713797 SUMMARY

[0008] In one embodiment, the microwave-induced exothermic composition includes an electrically conductive polymer and a resin. The resin is at least one selected from the group consisting of a styrene-butadiene copolymer, an acrylonitrile-butadiene copolymer, a vinyl acetate resin, and a silicone resin.

[0009] One embodiment of the present disclosure can provide a microwave-induced exothermic composition that achieves excellent adhesion to a substrate and excellent water resistance, as well as high water vapor permeability, when the microwave-induced exothermic composition is used in a microwave-induced exothermic film or a microwave-induced exothermic package. BRIEF DESCRIPTION OF DRAWINGS

[0010] [ Figure 1 ] Figure 1 is a schematic cross-sectional view illustrating one example of a microwave-induced exothermic film of one embodiment of the present disclosure.

[0011] [ Figure 2 ] Figure 2 is a schematic cross-sectional view illustrating another example of a microwave-induced exothermic film of the present embodiment.

[0012] [ Figure 3 ] Figure 3 is a schematic cross-sectional view illustrating still another example of a microwave-induced exothermic film of the present embodiment.

[0013] [ Figure 4 ] Figure 4 is a schematic cross-sectional view illustrating still another example of a microwave-induced exothermic film of the present embodiment.

[0014] [ Figure 5 ] Figure 5 is a schematic cross-sectional view illustrating still another example of a microwave-induced exothermic film of the present embodiment.

[0015] [ Figure 6 ] Figure 6 is a perspective view illustrating an example of a microwave-induced exothermic package of one embodiment of the present disclosure.

[0016] [ Figure 7 ] Figure 7 is a perspective view illustrating another example of a microwave-induced exothermic package of the present embodiment. DETAILED DESCRIPTION

[0017] Embodiments of the present application will be described below with reference to the accompanying drawings. Furthermore, the present application is not limited to these embodiments, but various changes and modifications can be made thereto without departing from the scope of the present application. In the present specification, unless otherwise specified, a numerical value range designated includes the upper limit and lower limit of the range described.

[0018] <microwave-induced exothermic composition> Embodiments of the microwave-induced exothermic composition of the present disclosure will be described below.

[0019] According to one embodiment of the present disclosure, the microwave-induced exothermic composition includes an electrically conductive polymer and a resin, the resin being at least one selected from the group consisting of a styrene-butadiene copolymer, an acrylonitrile-butadiene copolymer, a vinyl acetate resin, and a silicone resin. When the above microwave-induced exothermic composition is used for a microwave-induced exothermic film or a microwave-induced exothermic package, excellent adhesion to a substrate and excellent water resistance are achieved. Furthermore, during microwave heating, heat is generated by microwave irradiation to easily form an opening, thereby also achieving high water vapor permeability.

[0020] According to one embodiment of the present disclosure, the microwave-induced exothermic composition includes an electrically conductive polymer and a resin. The microwave-induced exothermic composition can further include other components.

[0021] <electrically conductive polymer> The electrically conductive polymer preferably includes at least one selected from the group consisting of polyaniline, polypyrrole, polythiophene, polyacetylene, polyisothianaphthene, polyethylene vinylene, poly(p-phenylene), polyphenylene vinylene, polyfluorene, polycarbazole, polyacene, polythiazyl, polyethylene vinylene, polyphenylene sulfide, polyperinaphthalene, polyacrylonitrile, polyoxadiazole, polyindole, polyazulene, polyfuran, phthalocyanine and phthalocyanine derivatives, polysilane, polygermane, porphyrin and porphyrin derivatives, graphene and graphene derivatives, perylene derivatives, tetrathiafulvalene derivatives, sulfur-containing heterocyclic compounds, oxygen-containing heterocyclic compounds, nitrogen-containing heterocyclic compounds, tetracyanoquinodimethane derivatives, fullerene, carbon nanotubes, and quinone.

[0022] Among the above-listed examples, more preferable are π-conjugated electrically conductive polymer compounds including a π-conjugated main chain, such as polythiophene, polypyrrole, polyaniline, polyacetylene, polyphenylene, polyphenylene vinylene, polyacene, and polythiophene vinylene. In view of ease of polymerization and stability in air, polythiophene, polypyrrole, and polyaniline are still more preferable.

[0023] Examples of polyaniline include polyaniline, poly(2-methylaniline), poly(3-methylaniline), poly(2-ethylaniline), poly(3-ethylaniline), poly(2-methoxyaniline), poly(3-methoxyaniline), poly(2-ethoxyaniline), poly(3-ethoxyaniline), poly(N-methylaniline), poly(N-propylaniline), poly(N-phenyl-1-naphthyl aniline), poly(8-anilino-1-naphthalenesulfonic acid), and poly(7-anilino-4-hydroxy-2-naphthalenesulfonic acid).

[0024] Examples of polyazoles include polyazoles, poly(1 -methylazole), poly(3- methylazole), poly(1 -ethylazole), poly(3-ethylazole), poly(1 -methoxyazole), poly(3- methoxyazole), poly(1 -ethoxyazole), and poly(3-ethoxyazole).

[0025] Examples of polythiophenes include polythiophene, polyisothiophene, polyethylene dioxythiophene (PEDOT), polyisoperylenethiophene, polydodecylthiophene, poly(3- methylthiophene), poly(3-hexylthiophene), poly(3-methoxythiophene), poly(3- ethoxythiophene), poly(3-hexylthiophene-2,5-diyl) (P3HT), poly(3-octylthiophene-2,5- diyl) (P3OT), poly(3-dodecylthiophene-2,5-diyl) (P3DDT), poly(3-(2- methoxyethyloxy)ethoxymethylthiophene-2,5-diyl), poly[(N-dodecyldioxopyrrolothiophene)-alt-(thiophene)] (PDT), poly(3-undecyl-2,2'-bithiophene), and poly(4- undecyl-2,2'-bithiophene).

[0026] Examples of polyacetylenes include polyacetylene and polydiacetylene.

[0027] Examples of polyisothianaphthalenes include polyisothianaphthalene.

[0028] Examples of poly(thienylenevinylene) include poly(thienylenevinylene). Examples of polyparaphenylene include polyparaphenylene and poly(2,5- dimethoxyphenylene).

[0029] Examples of polyphenylenevinylene include polyparaphenylenevinylene, poly(2,5- dimethoxyphenylenevinylene), and polynaphthalenevinylene.

[0030] Examples of polyfluorenes include polyfluorene and poly(C1-C20 alkylfluorene).

[0031] Examples of polycarbazoles include polycarbazole.

[0032] Examples of polyacenes include tetracene, pentacene, hexacene, heptacene, dipentacene, quaterrylene, perylene, chrysene, coronene, terrylenes, ovalenes, benzoperylene (quaterrylene), circulene, and derivatives of the foregoing.

[0033] Other examples include: electrically conductive polymer compounds such as polythiafulvene, polyethylene vinylene, polyphenylene sulfide, polyperinaphthylene, polyacrylonitrile, polyoxadiazole, polynaphthalene (e.g., polynaphthalene), polypyrylium (e.g., polypyrylium), polyazulene (e.g., polyazulene), polyfuran (e.g., polyfuran and polybenzofuran), phthalocyanine (e.g., phthalocyanine, copper phthalocyanine, zinc phthalocyanine, titanium oxyphtalocyanine, and poly[iron phthalocyanine (tetraxine)]) and phthalocyanine derivatives, polysilane compounds, and polygermane compounds; and low-molecular-weight electrically conductive compounds such as porphyrin (e.g., porphyrin, tetramethylporphyrin, tetraphenylporphyrin, diazotetraphenylporphyrin, monoazo tetraphenylporphyrin, diazotetraphenylporphyrin, azidotetraphenylporphyrin, octaethylporphyrin, octaalkylthioporphyrin, octaalkylaminopyrylium, hemipyrylium, and chlorophyll) and porphyrin derivatives, graphene and graphene derivatives, perylene derivatives (e.g., bis(benzimidazole) perylene), tetrathiafulvalene derivatives (e.g., dibenzotetrathiafulvalene), sulfur-containing heterocyclic compounds, oxygen-containing heterocyclic compounds, nitrogen-containing heterocyclic compounds (e.g., carbazole), tetracyanoquinonedimethane derivatives, fullerene derivatives, carbon nanotube derivatives, cyanine dyes, cyanine dyes, and quinones (e.g., benzoquinone and naphthoquinone).

[0034] (resin) As the resin, a styrene-butadiene copolymer, an acrylonitrile-butadiene copolymer, a vinyl acetate resin, a silicone resin, or the like can be used. The above-listed resins can be used alone or in combination. Among the above-listed examples, the acrylonitrile-butadiene copolymer and the silicone resin are preferable because they have excellent adhesion to the substrate and the formed image has excellent durability. Specific examples of the resin are listed, but the resin is not limited to the following listed resins.

[0035] Examples of the styrene-butadiene copolymer include the Nipol series (available from Zeon Corporation), the SBL series (available from ENEOS Materials Corporation), the Nalstar SBR / MBR series (available from NIPPON A&L Co., Ltd.), the LACSTAR series (available from DIC Corporation), and the SB Latex series (available from Asahi Kasei Corporation).

[0036] Examples of the acrylonitrile-butadiene copolymer include the Cyatex NBR series (available from NIPPON A&L Co., Ltd.) and the Nipol series (available from Zeon Corporation).

[0037] Examples of the vinyl acetate resin include the VINYLAN series (available from Nisshin Chemical Co., Ltd.), the CEVIAN-A series (available from Daicel Miraizu Co., Ltd.), and the Polysol series (available from Resonac Holdings Co., Ltd.).

[0038] Examples of the silicone resin include the DOWSIL series (available from Dow Toray Co., Ltd.) and the POLON series (available from Shin-Etsu Chemical Co., Ltd.).

[0039] In order to achieve the desired adhesion to the substrate, the glass transition temperature Tg of the resin is preferably -20 degrees Celsius or higher, more preferably -15 degrees Celsius or higher, and still more preferably 20 degrees Celsius or higher. When the glass transition temperature Tg of the resin is -20 degrees Celsius or higher, the desired adhesion to the substrate can be achieved. The upper limit of the glass transition temperature Tg of the resin is not particularly limited as long as the desired adhesion to the substrate is achieved. The upper limit of the glass transition temperature Tg of the resin can be lower than 25 degrees Celsius.

[0040] The amount of the resin is preferably 10 to 90 mass%, more preferably 20 to 80 mass%, and still more preferably 30 to 70 mass%, with respect to the solid content of the microwave-induced heat-releasing composition. When the amount of the resin is within the above range, the desired water resistance and water vapor permeability can be achieved.

[0041] (Other components) ((Dopant)) The dopant is not particularly limited as long as the dopant has a structure that functions as an acceptor or a donor with respect to the conductive polymer. The acceptor is a structure that can accept an electron, and the donor is a structure that can provide an electron.

[0042] The conductive polymer is doped with some functional groups included in the dopant, so that the dopant contributes to the conductivity of the conductive polymer. Examples of the functional groups included in the dopant include a carboxyl group, a hydroxyl group, a mercapto group, an amino group, a sulfinyl group, and a sulfonium group.

[0043] The carboxyl group-containing dopant is preferably a carboxylic acid aromatic compound or a carboxylic acid condensed aromatic compound that includes an aromatic ring or a condensed aromatic ring within the molecular structure. The aromatic ring or the condensed aromatic compound has many resonance structures, and inhibits a hydrolysis reaction. Due to the use of the carboxylic acid aromatic compound or the carboxylic acid condensed aromatic compound, a microwave-induced heat-releasing composition having improved water resistance can be obtained.

[0044] The carboxylic aromatic compound or carboxylic condensed ring aromatic compound is not particularly limited. Examples of the carboxylic aromatic compound and carboxylic condensed ring compound include: carboxylic aromatic compounds such as phthalic acid, trimellitic acid, trimesic acid, hemimellitic acid, benzene pentacarboxylic acid, and benzene hexacarboxylic acid; carboxylic aromatic compound derivatives such as 4-sulfophthalic acid; carboxylic aromatic condensation compounds such as compounds obtained by substituting naphthalene with only a carboxylic acid (e.g., 1,4-naphthalene dicarboxylic acid, 2,3-naphthalene dicarboxylic acid, 2,6-naphthalene dicarboxylic acid, and 1,8-naphthalene dicarboxylic anhydride) and derivatives thereof; carboxylic condensation compounds (e.g., 4-chloro-1,8-naphthalene dicarboxylic anhydride, 4-sulfo-1,8-naphthalene dicarboxylic anhydride, and naphthalene-1,4,5,8-tetracarboxylic acid) and derivatives thereof; anthracene ring-containing compounds such as 2,3-anthracene dicarboxylic anhydride; and carboxylated polycyclic aromatic hydrocarbons (e.g., tetracene, pentacene, benzpyrene, chrysene, coronene, pyrene, triphenylene, corannulene, buckminsterfullerene, and ovalene) and derivatives of the carboxylated polycyclic aromatic hydrocarbons.

[0045] Examples of the hydroxyl group-containing dopant include salicylic acid, m-hydroxybenzoic acid, p-hydroxybenzoic acid, 4-hydroxyphthalic acid, 3-hydroxyphthalic anhydride, 3,6-dihydroxyphthalic acid, phenol sulfonic acid, 3-hydroxy-2,7-naphthalene dicarboxylic acid, and derivatives of the above.

[0046] Examples of the sulfhydryl group-containing dopant include mercaptoacetic acid, mercaptosuccinic acid, 2-mercaptobutyric acid, 4-mercaptobutyric acid, 2-mercaptoethanol, 2-mercaptobenzoic acid, 3-mercaptobenzoic acid, 4-mercaptobenzoic acid, o-aminobenzenethiol, m-aminobenzenethiol, p-aminobenzenethiol, 2-hydroxybenzenethiol, 3-hydroxybenzenethiol, 4-hydroxybenzenethiol, and derivatives of the above.

[0047] Examples of the amino group-containing dopant include aminomethanesulfonic acid, 1-amino-2-naphthol-4-sulfonic acid, 2-amino-5-naphthol-7-sulfonic acid, 3-aminopropanesulfonic acid, N-cyclohexyl-3-aminopropanesulfonic acid, o-aminobenzenesulfonic acid, m-aminobenzenesulfonic acid, p-aminobenzenesulfonic acid, 4-amino-2-chlorotoluene-5-sulfonic acid, 4-amino-3-methylbenzene-1-sulfonic acid, 4-amino-5-methoxy-2-methylbenzenesulfonic acid, 2-amino-5-methylbenzene-1-sulfonic acid, 4-amino-2-methylbenzene-1-sulfonic acid, polycarboxylic acids (e.g., polyacrylic acid, polymethacrylic acid, and polymaleic acid), and derivatives of the above.

[0048] Examples of the sulfino group-containing dopant include derivatives of methylsulfinic acid, ethylsulfinic acid, isopropylsulfinic acid, phenylsulfinic acid, p-toluenesulfinic acid, cyclopropanesulfinic acid, p-chlorobenzenesulfinic acid, hydroxymethylsulfinic acid, L-cysteine sulfinic acid, 2-aminoethylsulfinic acid, and derivatives of the above.

[0049] Examples of the dopant containing a sulfonium group include low-molecular-weight sulfonic acids and salts of low-molecular-weight sulfonic acids, and high-molecular-weight acids containing a sulfonic acid group and salts of high-molecular-weight acids containing a sulfonic acid group.

[0050] Examples of the low-molecular-weight sulfonic acid include alkyl sulfonic acids, benzene sulfonic acids, naphthalene sulfonic acids, anthraquinone sulfonic acids, camphor sulfonic acids, and derivatives of the above. The low-molecular-weight sulfonic acid is particularly preferably a low-molecular-weight organic acid having a molecular weight of 1000 or less.

[0051] Examples of the alkyl sulfonic acid include 2-acrylamido-2-methylpropane sulfonic acid, dodecylbenzene sulfonic acid, and derivatives of the above.

[0052] Examples of the benzene sulfonic acid include toluene sulfonic acid, styrene sulfonic acid, and derivatives of the above.

[0053] Examples of the naphthalene sulfonic acid include 1-naphthalene sulfonic acid, 2-naphthalene sulfonic acid, 1,3-naphthalene disulfonic acid, 1,3,6-naphthalene trisulfonic acid, 6-ethyl-1-naphthalene sulfonic acid, and derivatives of the above.

[0054] Examples of the anthraquinone sulfonic acid include anthraquinone-1-sulfonic acid, anthraquinone-2-sulfonic acid, anthraquinone-2,6-disulfonic acid, 2-methylanthraquinone-6-sulfonic acid, and derivatives of the above.

[0055] Examples of the camphor sulfonic acid include (+)-10-camphor sulfonic acid, (-)-10-camphor sulfonic acid, and derivatives of the above. In addition, the camphor sulfonic acid can be a racemate.

[0056] Among the above-listed examples, benzene sulfonic acid, toluene sulfonic acid, and naphthalene sulfonic acid are preferred. The above-listed examples can be used alone or in combination.

[0057] In the case where the low-molecular-weight sulfonic acid is an alkyl sulfonic acid, a benzene sulfonic acid, a naphthalene sulfonic acid, an anthraquinone sulfonic acid, a camphor sulfonic acid, or a derivative of a low-molecular-weight sulfonic acid, the low-molecular-weight sulfonic acid can be a salt of a low-molecular-weight organic acid. Examples of the salt of a low-molecular-weight organic acid include ammonium salts and sodium salts.

[0058] Examples of the high-molecular-weight acid of the high-molecular-weight acid containing a sulfonic acid group include polycarboxylic acids such as polyacrylic acid, polymethacrylic acid, and polymaleic acid; polysulfonic acids such as polyvinyl sulfonate and polystyrene sulfonate; and copolymers including any of the above as a structural unit. Among the above-listed examples, polystyrene sulfonate (PSS) is preferred. The above-listed high-molecular-weight acids can be used alone or in combination.

[0059] The weight average molecular weight (Mw) of the high-molecular-weight acid is preferably 2000 to 500000, and more preferably 10000 to 200000.

[0060] The amount of the dopant in the microwave-induced exothermic composition is preferably 20 parts by mass to 3000 parts by mass, and more preferably 30 parts by mass to 1000 parts by mass, relative to 100 parts by mass of the electrically conductive polymer.

[0061] As the dopant, a single dopant can be used, or two or more kinds of dopants can be used in combination.

[0062] (Solvent) The solvent is not particularly limited as long as the solvent can maintain the electrically conductive polymer in a dissolved and dispersed state. The solvent can be a single solvent, or a mixture of two or more kinds of solvents. The solvent can be appropriately selected from a protic polar solvent (for example, water, methanol, ethanol, propanol, and acetic acid) and an aprotic nonpolar solvent. The above examples can be used alone or in combination.

[0063] As the solvent, a high-boiling-point solvent having a melting point of 100 degrees Celsius to 350 degrees Celsius is preferably used.

[0064] The high-boiling-point solvent is not particularly limited as long as the high-boiling-point solvent is a solvent having a melting point of 100 degrees Celsius to 350 degrees Celsius. The high-boiling-point solvent can be a single solvent, or a mixture of two or more kinds of solvents. Examples of the high-boiling-point solvent include, but are not limited to, ethylene glycol, diethylene glycol, diethylene glycol monobutyl ether, dibutylene glycol monoethyl ether, diethylene glycol monoethyl ether acetate, diethylene glycol monomethyl ether, DMSO, formamide, glycerol, propylene glycol, 1,3-butanediol, and dipropylene glycol. Among the above-listed examples, ethylene glycol, diethylene glycol, DMSO, glycerol, propylene glycol, 1,3-butanediol, and dipropylene glycol are preferably used.

[0065] The amount of the solvent in the microwave-induced exothermic composition is preferably 0.01% to 50% by mass, and more preferably 1% to 10% by mass. The amount of the solvent in the microwave-induced exothermic composition is 0.01% to 50% by mass, which can improve the exothermic effect, and can improve the drying speed of the microwave-induced exothermic composition to improve the productivity.

[0066] The microwave-induced exothermic composition is preferably in a dissolved or stably dispersed state. The microwave-induced exothermic composition can be in a temporarily dispersed state by mechanical stirring.

[0067] To improve the design, applicability, required physical properties (for example, hue), ink stability, and printability, the microwave-induced exothermic composition of the present disclosure can include a colorant, a solvent, water, a wax, a pigment dispersant, a resin, a crosslinking agent, an inorganic filler, an organic filler, an antifoaming agent, a leveling agent, an anticaking agent, an antistatic agent, a pH adjustor, a slip aid additive, a plasticizer, an adhesion promoter, and the like. The above-listed components can be appropriately selected as long as the used components do not adversely affect the properties of the microwave-induced exothermic composition.

[0068] ((coloring agent)) As the coloring agent, a pigment, a dye, or a mixture of the above can be added.

[0069] Examples of the pigment include: inorganic pigments such as titanium oxide, red iron oxide, barium sulfate, calcium carbonate, silica, zinc oxide, zinc sulfide, mica, talc, pearl, aluminum, and carbon black; organic pigments such as phthalocyanine pigments, insoluble azo pigments, condensed azo pigments, dioxazine pigments, anthraquinone pigments, quinacridone pigments, perylene pigments, pyromethene pigments, and thioindigo pigments; and various other fluorescent pigments, metal powder pigments, and filler pigments. The pigments listed above can be used alone or in combination.

[0070] The dye is preferably a dye that is dissolved or dispersed in a solvent. As the dye, a single dye can be used, or two or more dyes can be used in combination. Among the coloring agent examples listed above, a pigment is preferably used in view of durability. The use of a coloring agent in the microwave-induced exothermic composition is very effective in view of color variation and design.

[0071] ((solvent)) The microwave-induced exothermic composition can include a solvent for imparting appropriate fluidity or adjusting the viscosity in the printing process. The solvent is not particularly limited as long as the solvent can dissolve or disperse the constituent components of the microwave-induced exothermic composition, and can maintain the fluidity of the microwave-induced exothermic composition. The solvent is suitably selected from commonly used organic solvents and water.

[0072] Examples of the organic solvent include aromatic hydrocarbon-based solvents (e.g., toluene and xylene), aliphatic hydrocarbon-based solvents (e.g., hexane, cyclohexane, methylcyclohexane, and ethylcyclohexane), alcohol-based solvents (e.g., methanol, ethanol, isopropyl alcohol (IPA), n-propanol, 1-butanol, 2-butanol, isobutyl alcohol, and t-butyl alcohol), ester-based solvents (e.g., ethyl acetate, n-propyl acetate, isopropyl acetate, butyl acetate, isobutyl acetate, sec-butyl acetate, and t-butyl acetate), ketone-based solvents (e.g., acetone, methyl ethyl ketone (MEK), methyl isobutyl ketone, and cyclohexanone), glycol ether-based solvents (e.g., ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol dimethyl ether, ethylene glycol monobutyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monopropyl ether, and propylene glycol monobutyl ether), and esterified (e.g., acetylated) products of the glycol ether-based solvents (e.g., ethylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate, ethylene glycol monobutyl ether acetate, diethylene glycol monoethyl ether acetate, diethylene glycol monobutyl ether acetate, propylene glycol monomethyl ether acetate, and propylene glycol monoethyl ether acetate). Among the above-listed examples, toluene, ethyl acetate, n-propyl acetate, n-propanol, isopropyl alcohol, methyl ethyl ketone, and water are more preferable in terms of printability and availability. The above-listed examples can be used alone or in combination.

[0073] The amount of the solvent in the microwave-induced exothermic composition is preferably 30 to 99.99% by mass, and more preferably 40 to 99.9% by mass.

[0074] ((wax)) The wax is not particularly limited, and can be appropriately selected depending on the intended purpose. The wax can be selected from waxes and monomeric organic hydrophobic materials. Examples of the wax include canawa wax, beeswax, montan wax, paraffin wax, and synthetic wax. Examples of the monomeric organic hydrophobic material include biphenyl, o-terphenyl, naphthalene, and anthracene. The above-listed examples can be used alone or in combination.

[0075] ((pigment dispersant)) The pigment dispersant is not particularly limited, and can be appropriately selected depending on the intended purpose. Examples of the pigment dispersant include anionic surfactants, cationic surfactants, and nonionic surfactants. The above-listed examples can be used alone or in combination.

[0076] ((other resin)) As the other resin, a resin other than the above-described styrene-diene copolymer, acrylonitrile-diene copolymer, vinyl acetate resin, and silicone resin can be used.

[0077] ((crosslinking agent)) The crosslinking agent is not particularly limited, and can be appropriately selected depending on the intended purpose. Examples of the crosslinking agent include hydrazide-based crosslinking agents, isocyanate-based crosslinking agents, epoxy-based crosslinking agents, carbodiimide-based crosslinking agents, silane coupling-based crosslinking agents, oxazoline-based crosslinking agents, aziridine-based crosslinking agents, imine-based crosslinking agents, metal chelate-based crosslinking agents, glyoxal-based crosslinking agents, and methylol-based crosslinking agents. The above-listed examples can be used alone or in combination. Among the above-listed examples, preferred are isocyanate-based crosslinking agents, carbodiimide-based crosslinking agents, epoxy-based crosslinking agents, and aziridine-based crosslinking agents.

[0078] As described above, the microwave-induced exothermic composition of the present disclosure includes an electrically conductive polymer and a resin, the resin being at least one selected from the group consisting of a styrene-butadiene copolymer, an acrylonitrile-butadiene copolymer, a vinyl acetate resin, and a silicone resin. The microwave-induced exothermic layer formed using the microwave-induced exothermic composition of the present disclosure easily generates heat by microwave irradiation to achieve high water vapor permeability. Thus, when the microwave-induced exothermic layer is disposed to overlap with a heat-sealed portion of a microwave-induced exothermic film, an opening is easily formed in the heat-sealed portion due to melting or shrinkage of the film. When the microwave-induced exothermic layer is disposed at a central portion of a microwave-induced exothermic film, an opening is easily formed at the central portion due to rupture of the microwave-induced exothermic film.

[0079] When the microwave-induced exothermic composition is used for a microwave-induced exothermic layer of a microwave-induced exothermic film or a microwave-induced exothermic package, the microwave-induced exothermic composition has excellent adhesion to a substrate, the resulting microwave-induced exothermic film or microwave-induced exothermic package has excellent water resistance, and the resulting microwave-induced exothermic layer is not easily peeled even when the microwave-induced exothermic layer is in contact with water. Thus, using the microwave-induced exothermic composition of the present disclosure can minimize rupture of the microwave-induced exothermic layer of the microwave-induced exothermic film or microwave-induced exothermic package, as well as heat generation failure and contamination of food.

[0080] The resin in the microwave-induced exothermic composition of the present disclosure can have a glass transition temperature Tg of -20 degrees Celsius or higher. The microwave-induced exothermic composition of the present disclosure including the above-described resin can maintain flexibility of the resin and enhance adhesion to a substrate. Thus, when the microwave-induced exothermic composition of the present disclosure is used for a microwave-induced exothermic layer of a microwave-induced exothermic film or a microwave-induced exothermic package, adhesion of the microwave-induced exothermic layer to a substrate can be further improved.

[0081] In the microwave-induced heat releasing composition of the present disclosure, the amount of the resin can be 10 to 90 mass% with respect to the solid content of the microwave-induced heat releasing composition. The use of the microwave-induced heat releasing composition of the present disclosure can improve high water resistance without causing the microwave-induced heat releasing layer to peel off upon contact with water. Thus, when the microwave-induced heat releasing composition of the present disclosure is used for the microwave-induced heat releasing layer of a microwave-induced heat releasing film or a microwave-induced heat releasing package, high water vapor permeability is easily achieved, and water resistance can be improved.

[0082] The microwave-induced heat releasing composition of the present disclosure can further include a dopant. Thus, the electrically conductive polymer doped with the dopant can be safely incorporated into the microwave-induced heat releasing composition so that heat is easily generated by microwave irradiation. When the microwave-induced heat releasing composition of the present disclosure is used for the microwave-induced heat releasing layer of a microwave-induced heat releasing film or a microwave-induced heat releasing package, an opening is easily formed in the microwave-induced heat releasing layer to achieve high water vapor permeability, and water resistance can be improved.

[0083] The microwave-induced heat releasing composition of the present disclosure can further include a high-boiling point solvent having a boiling point of 100 to 350 degrees Celsius. Since the high-boiling point solvent is included in the microwave-induced heat releasing composition of the present disclosure, the electrically conductive polymer is more uniformly arranged within the microwave-induced heat releasing composition during the drying process of the microwave-induced heat releasing composition. Thus, when the microwave-induced heat releasing composition is used for the microwave-induced heat releasing layer of a microwave-induced heat releasing film or a microwave-induced heat releasing package, high water vapor permeability can be safely achieved, and water resistance can be ensured.

[0084] <microwave-induced heat releasing layer> According to one embodiment of the present disclosure, the microwave-induced heat releasing layer is a layer (coating layer) formed by using the microwave-induced heat releasing composition of the present disclosure. Specifically, the microwave-induced heat releasing layer includes an electrically conductive polymer and a resin, wherein the resin is at least one selected from the group consisting of a styrene-butadiene copolymer, an acrylonitrile-butadiene copolymer, a vinyl acetate resin, and a silicone resin.

[0085] According to the above-described embodiment of the present disclosure, a microwave-induced heat releasing layer having excellent adhesion to a substrate and excellent water resistance as well as high water vapor permeability can be provided.

[0086] The microwave-induced heat releasing layer of the present disclosure can be formed on at least one face of a substrate, for example, by coating.

[0087] The substrate is not particularly limited. As the substrate, the same substrate as that of the microwave-induced heat releasing film can be used.

[0088] The coating method is not particularly limited and can be selected from conventional coating methods.

[0089] The thickness of the microwave-induced heat releasing layer of the present disclosure is preferably 0.01 μm (micrometer) to 10 μm (micrometer), and more preferably 0.05 μm (micrometer) to 3 μm (micrometer). When the film thickness of the microwave-induced heat releasing layer is 0.01 μm (micrometer) to 10 μm (micrometer), heat is sufficiently generated, and proper barrier properties are achieved.

[0090] The microwave-induced heat releasing layer of the present disclosure is a coating layer formed by using the microwave-induced heat releasing composition of the present disclosure. Therefore, the microwave-induced heat releasing layer generates heat by microwave irradiation during microwave heating, making it easy to form an opening in a microwave-induced heat releasing film or a microwave-induced heat releasing package to achieve high water vapor permeability, as well as to achieve excellent adhesion to a substrate and excellent water resistance.

[0091] <microwave-induced heat releasing film> According to one embodiment of the present disclosure, the microwave-induced heat releasing film includes a substrate and a microwave-induced heat releasing layer, and can further include a sealant and an adhesive layer as needed. The microwave-induced heat releasing layer is the above-described microwave-induced heat releasing layer of the present disclosure.

[0092] According to the above-described embodiment of the present disclosure, a microwave-induced heat releasing film achieving excellent adhesion to a substrate and excellent water resistance, as well as high water vapor permeability, can be provided.

[0093] The substrate is preferably at least one selected from the group consisting of paper, a plastic film or sheet, and a laminated material imparting sealability. Examples of the plastic film or sheet include a polyester film (e.g., polyethylene terephthalate (PET) and polyethylene naphthalate (PEN)), a polyolefin film (e.g., polyethylene, polypropylene, ethylene-vinyl acetate), a polystyrene film, an alcohol-based film (e.g., ethylene-vinyl alcohol and polyvinyl alcohol), a polyamide film, a barrier polyamide film provided with a barrier layer between polyamide films, glassine paper, moisture-proof glassine paper, a transparent vapor-deposited polyester film or a transparent vapor-deposited polyamide film (in which a vapor-deposited layer of aluminum oxide or silicon dioxide is deposited on a PET film or a polyamide film), and various coating films obtained by coating a polyvinylidene chloride resin, a polyvinyl alcohol resin, a polyacrylic acid resin, an anchor coating resin, and the like. The above-listed examples can be a uniaxially oriented film or a cast film. The substrate can have a laminated structure of one or more layers selected from the above-listed films. The substrate is appropriately selected in consideration of the required mechanical strength or dimensional stability.

[0094] Further, a corona treatment, a low-temperature plasma treatment, frame processing, solvent treatment, or coating can be performed on the coated surface of the substrate to improve adhesion to the microwave-induced heat releasing composition. Alternatively, the substrate can be selected from a surface-treated film that has been subjected to any one of the above-listed treatments.

[0095] The substrate can be a laminate in which a thermoplastic resin film or sheet is stacked by dry lamination, non-solvent lamination, or extrusion lamination, or a laminate in which films or sheets are stacked together via an adhesive, or any combination of the foregoing. The substrate can be a monoaxially oriented film, a readily cuttable film, a stretchable film, or a shrinkable film.

[0096] Further, the substrate can be a laminate imparted with sealability. Examples of methods for imparting sealability include: a method of combining a sealant film or sheet available in the relevant field to the substrate; and a method of coating the substrate with a resin by extrusion lamination. A layer imparted with sealability by the above-listed methods is referred to as a sealant.

[0097] Further, the substrate can be subjected to a blast in advance.

[0098] The thickness of the substrate is not particularly limited, provided that the thickness of the substrate is within a range that does not adversely affect printability and winding suitability. The thickness of the substrate is preferably 5 μm (micrometers) to 300 μm (micrometers), and more preferably 6 μm (micrometers) to 250 μm (micrometers).

[0099] The microwave-induced heat releasing film according to one embodiment of the present disclosure can preferably include a sealant as needed.

[0100] The sealant is preferably a layer including a resin having sealability. Examples of the resin used in the sealant include thermoplastic resins such as polyethylene resins (e.g., LDPE, LLDPE, HDPE, and metallocene polyethylene), polypropylene resins, ethylene-vinyl acetate copolymers, ionomer resins, ethylene-acrylic acid copolymers, ethylene-ethyl acrylate copolymers, ethylene-methyl acrylate copolymers, ethylene-methacrylic acid copolymers, ethylene-methyl methacrylate copolymers, ethylene-propylene copolymers, methylcyclohexane polymers, acid-modified polyolefin resins (e.g., polyethylene or polypropylene modified with maleic acid or fumaric acid), and polystyrene resins. The above-listed resins can be used alone or in combination.

[0101] A film including any one of the above-listed resins or a laminate including two or more films including any one of the above-listed resins can be formed by lamination (e.g., dry lamination, wet lamination, non-solvent lamination, and thermal lamination), resin coating (e.g., extrusion lamination), thermal sealant coating, or by hot melt adhesive bonding. The film or laminate including the above-listed resins does not necessarily have to be formed on the entire surface of the microwave-induced heat releasing film, but can be formed on a seal region.

[0102] Examples of the film include polyolefin films such as polyethylene, polypropylene, mixed resins of polyethylene and polypropylene, ethylene-vinyl acetate copolymer resins, ethylene-(meth)acrylic acid copolymer resins, ethylene-(meth)acrylic acid methyl ester copolymer resins, ethylene-(meth)acrylic acid ethyl ester copolymer resins, and ethylene-vinyl alcohol copolymer resins.

[0103] Examples of the resin for the resin coating or the resin for the hot melt adhesive for extrusion lamination include thermoplastic resins such as polyethylene resins (e.g., LDPE, LLDPE, and HDPE), polypropylene resins, ethylene-vinyl acetate copolymers, ionomer resins, ethylene-acrylic acid copolymers, ethylene-ethyl acrylate copolymers, ethylene-methyl acrylate copolymers, ethylene-methacrylic acid copolymers, ethylene-methacrylic acid methyl ester copolymers, ethylene-propylene copolymers, methylterepolymer, acid-modified polyolefin resins (e.g., polyethylene or polypropylene modified with maleic acid or fumaric acid), and polystyrene resins. The above-listed resins can be used alone or in combination.

[0104] The thickness of the sealant is not particularly limited. In consideration of the sealability, cost, and productivity, the thickness of the film as the sealant is preferably 2 μm (micrometers) to 200 μm (micrometers), the thickness of the extrusion lamination resin coating as the sealant is preferably 1 μm (micrometers) to 100 μm (micrometers), the thickness of the coated hot sealant as the sealant is preferably 0.1 μm (micrometers) to 10 μm (micrometers), and the thickness of the coated hot melt adhesive as the sealant is preferably 1 μm (micrometers) to 50 μm (micrometers).

[0105] The microwave-induced heat releasing film of the present disclosure can further include an adhesive layer. For example, the adhesive layer is disposed between the substrate and another substrate, or between the substrate and the sealant. The adhesive layer is configured to adhere two layers together using an adhesive or a pressure-sensitive adhesive including wax and a hot melt adhesive.

[0106] Examples of the resin for forming the adhesive layer include resins having sealability for forming the above-described sealant, urethane resins, butadiene resins, polyvinyl acrylimide resins, isocyanate resins, and chelates. As the resin for forming the adhesive layer, commercially available adhesives can be used. In addition, the adhesive can be a one-component adhesive in which a main component and a curing agent are mixed, or a two-component adhesive in which a main component and a curing agent are included separately. In the case where the resin for forming the adhesive layer is a two-component adhesive, the mixing ratio of the main component and the curing agent is appropriately adjusted to mix the main component with the curing agent.

[0107] The microwave-induced heat releasing film of the present disclosure can further include a finishing layer on the microwave-induced heat releasing layer.

[0108] The microwave-induced heat releasing film according to one embodiment of the present disclosure can further include other layers. Examples of the other layers include an OPP film, an ONY film, a PET film, an EVOH film, a PVA film, a glassine film, a barrier nylon film, an oriented polyethylene film, a (modified) polyacrylic acid coating film, a PVA coating film, a transparent vapor deposition film in which an inorganic oxide (e.g., aluminum oxide and silicon oxide) is deposited on an oriented polyethylene terephthalate film through vapor deposition, a transparent barrier film (K coating) in which a base film (e.g., OPP, ONY, PET, and glassine) is coated with polyvinylidene chloride (PVDC), and a barrier film in which an OPP film or an NY film is laminated with an ethylene-vinyl alcohol copolymer resin. The films listed above can be provided on the side of the base opposite to the side on which the coating film is provided.

[0109] The microwave-induced heat releasing film of the present disclosure can include a printed ink layer provided between predetermined layers. Any typical printed ink is used for the printed ink layer. The printed ink is appropriately selected depending on the base. The printed ink is preferably a gravure ink, which includes a resin such as urethane resin, vinyl chloride-vinyl acetate copolymer resin, nitrocellulose, polyamide resin, acrylic resin, chlorinated polypropylene resin, and polyester resin, in view of printability and availability. The gravure ink can include one or two or more of the resins listed above. In the case where two or more color gravure inks are used, the inks used can not include the same resin, and inks including mutually different resins can be appropriately used in combination.

[0110] The microwave-induced heat releasing film of the present disclosure can include an anchor coating layer between the base and the microwave-induced heat releasing layer. The anchor coating layer can be transparent. Alternatively, the anchor coating layer can be formed by using an anchor coating agent including a colorant, thereby achieving many different color variations and color designs.

[0111] Examples of the microwave-induced heat releasing film of the present disclosure are shown in Figures 1 to 5 FIGS. 1A to 1C.

[0112] As shown in Figure 1 FIG. 1A, the microwave-induced heat releasing film 1A includes a base 11, a microwave-induced heat releasing layer 12, and a sealant 13, in which the sealant 13, the base 11, and the microwave-induced heat releasing layer 12 are stacked in this order. The microwave-induced heat releasing film 1A includes the microwave-induced heat releasing layer 12 provided on at least a portion of one face of the base 11, and the sealant 13 can be provided on the entire area of the other face of the base 11. The microwave-induced heat releasing layer 12 can be provided on the entire area of one face of the base 11, and the sealant 13 can be provided on at least a portion of the other face of the base 11.

[0113] As shown in Figure 2As shown in FIG. 1, the microwave-induced heat releasing film 1A includes the base 11, the microwave-induced heat releasing layer 12, and the sealant 13, in which the sealant 13, the microwave-induced heat releasing layer 12, and the base 11 are stacked in this order. Figure 1 As shown in FIG. 1, the microwave-induced heat releasing film 1A includes the base 11, the microwave-induced heat releasing layer 12, and the sealant 13, in which the sealant 13, the microwave-induced heat releasing layer 12, and the base 11 are stacked in this order.

[0114] As shown in FIG. 1, the microwave-induced heat releasing film 1A includes the base 11, the microwave-induced heat releasing layer 12, and the sealant 13, in which the sealant 13, the microwave-induced heat releasing layer 12, and the base 11 are stacked in this order. Figure 3 As shown in FIG. 1, the microwave-induced heat releasing film 1A includes the base 11, the microwave-induced heat releasing layer 12, and the sealant 13, in which the sealant 13, the microwave-induced heat releasing layer 12, and the base 11 are stacked in this order. Figure 1 As shown in FIG. 1, the microwave-induced heat releasing film 1A includes the base 11, the microwave-induced heat releasing layer 12, and the sealant 13, in which the sealant 13, the microwave-induced heat releasing layer 12, and the base 11 are stacked in this order.

[0115] As shown in FIG. 1, the microwave-induced heat releasing film 1A includes the base 11, the microwave-induced heat releasing layer 12, and the sealant 13, in which the sealant 13, the microwave-induced heat releasing layer 12, and the base 11 are stacked in this order. Figure 4 As shown in FIG. 1, the microwave-induced heat releasing film 1A includes the base 11, the microwave-induced heat releasing layer 12, and the sealant 13, in which the sealant 13, the microwave-induced heat releasing layer 12, and the base 11 are stacked in this order.

[0116] As shown in FIG. 1, the microwave-induced heat releasing film 1A includes the base 11, the microwave-induced heat releasing layer 12, and the sealant 13, in which the sealant 13, the microwave-induced heat releasing layer 12, and the base 11 are stacked in this order. Figure 5 As shown in FIG. 1, the microwave-induced heat releasing film 1A includes the base 11, the microwave-induced heat releasing layer 12, and the sealant 13, in which the sealant 13, the microwave-induced heat releasing layer 12, and the base 11 are stacked in this order. Figure 1 As shown in FIG. 1, the microwave-induced heat releasing film 1A includes the base 11, the microwave-induced heat releasing layer 12, and the sealant 13, in which the sealant 13, the microwave-induced heat releasing layer 12, and the base 11 are stacked in this order.

[0117] <Method for producing microwave-induced heat releasing film> The method for producing a microwave-induced heat releasing film according to one embodiment of the present disclosure includes forming a microwave-induced heat releasing layer including a microwave-induced heat releasing composition on at least one face of a base (formation of microwave-induced heat releasing layer).

[0118] According to the above-described embodiments of the present disclosure, it is possible to provide a method for producing a microwave-induced heat releasing film that achieves excellent adhesion to a base and excellent water resistance and high water vapor permeability.

[0119] The formation of the microwave-induced heat releasing layer is preferably printing to form the microwave-induced heat releasing composition on the substrate. The printing is preferably at least one selected from the group consisting of screen printing, gravure printing, offset printing, flexographic printing, roll coating, brush coating, spray coating, knife coating, and inkjet printing. Among the above-listed examples, in view of high quality and high productivity, it is preferable to be gravure printing, flexographic printing, inkjet printing, or screen printing, more preferable to be gravure printing, and particularly even more preferable to be gravure printing using a multi-color gravure printing machine. Since printing is used, the coating layer can be provided in two or more regions, and the coating layers can be superimposed. Thus, it is easy to form water vapor-permeable openings, and it is easy to control heat generation.

[0120] After forming the substrate in which one or more films are laminated by the above-described lamination method, the microwave-induced heat releasing layer can be formed on one face of the substrate by any one of various printing methods (superimposed printing of the microwave-induced heat releasing composition). After forming the microwave-induced heat releasing layer on the face of the substrate by the printing method, another substrate can be formed on the other face of the substrate by any one of the above-described lamination methods. Furthermore, the microwave-induced heat releasing layer can be formed on both faces of the substrate.

[0121] In the case where a finish layer is provided on the microwave-induced heat releasing layer, the finish layer can be formed with a finish agent, a finish varnish, or an overprint varnish.

[0122] According to the method for producing a microwave-induced heat releasing film of the present disclosure, the printing performed for forming the microwave-induced heat releasing layer, the printing ink layer, and the anchor coating layer can be gravure printing by one or more units of a multi-color gravure printing machine. The use of gravure printing enables sequential formation of the microwave-induced heat releasing layer, the printing ink layer, the anchor coating layer, and the like on a substrate in one production line, enabling easy production of the microwave-induced heat releasing film in a sequential process flow (single pass) at low cost. Furthermore, it is easy to form water vapor-permeable openings or control heat generation. When the above-described layers cannot be sequentially formed on one production line due to the specifications of the gravure printing machine, the printing environment, or the facilities used, the above-described layers can be produced off-line (offline).

[0123] In the case where the microwave-induced heat releasing layer is formed by gravure printing, if heat is excessively generated with a dot area percentage of 100%, or depending on the easiness of formation of water vapor-permeable openings desired, by reducing the dot area percentage, adjusting the plate depth, or adjusting the dilution rate of the microwave-induced heat releasing composition, it is easy to control the easiness of openings or heat generation.

[0124] The microwave-induced exothermic layer can be formed only in the area where the opening is desired to be formed. Alternatively, the microwave-induced exothermic layer can be formed on the entire surface. Further, different coating patterns of the microwave-induced exothermic layer, such as a graphic pattern and design, can be formed according to the desired shape of the opening through which water vapor passes or the expected ease of opening.

[0125] Further, the printing is preferably intaglio printing using one or more color intaglio printing inks, so that a predetermined printing ink layer can be formed on the face of the substrate opposite to the face provided with the microwave-induced exothermic layer, or between the substrate and the microwave-induced exothermic layer, or between the microwave-induced exothermic layer and the anchor coating layer.

[0126] Further, the printing is preferably intaglio printing by a multi-color intaglio printing press. The microwave-induced exothermic layer is substantially colorless and transparent. Since the printing ink layer can be formed simultaneously by intaglio printing in one production line (on-line) without hindering other information, such as a graphic pattern, various colors or color designs can be imparted to the microwave-induced exothermic layer. For example, the design of the package can be imparted to enhance the appeal to consumers, or information about the opening area, opening method, or matters to be noted can be displayed, or information such as a company name, a logo, a product name, a mascot illustration, contents, ingredients, a notice of promotion, or a method of application, a method of alleviation or use, a date, a place of production, and a lottery number can be imparted.

[0127] Further, the method can further include forming an intermediate layer, an anchor coating layer, or a finish layer. The formation of the above-listed layers is not particularly limited except for using any formation method available in the related art, such as bonding and coating.

[0128] Each composition, such as the microwave-induced exothermic composition, the printing ink, and the anchor coating agent, can be prepared by uniformly dissolving or dispersing an electrically conductive organic compound, a resin, a pigment, a sealable resin, various additives, and the like in a solvent according to any method available in the related art. For the dissolution or dispersion, various stirrers or dispersers, such as a dissolver, a roll mill, a ball mill, a bead mill, a sand mill, a grinder, a paint shaker, a blender, a HENSCHEL mixer, a colloid mill, a pearl mill, an ultrasonic homogenizer, a wet jet mill, a kneader, and a homogenizer, can be used. The above-listed stirrers or dispersers can be used alone or in combination. In the case where bubbles or coarse particles are included in the composition, these bubbles or coarse particles can impair the printing performance or printing quality of the composition. Therefore, it is preferable to remove the bubbles or coarse particles from the composition using a filter device or a centrifuge available in the related art.

[0129] The viscosity of the above composition is not particularly limited, as long as the printing of the composition can be performed without any problems. The viscosity of the composition at 25 degrees Celsius is preferably 10 millipascal seconds to 1000 millipascal seconds, in view of the workability of the preparation and handling of the composition. In the case where the composition is used as a gravure printing ink, the viscosity of the composition is more preferably 10 millipascal seconds to 500 millipascal seconds.

[0130] The viscosity can be measured by a commercially available viscometer, such as a Brookfield viscometer.

[0131] The microwave-induced heat releasing film of the present disclosure includes a microwave-induced heat releasing layer, wherein the microwave-induced heat releasing layer includes the above microwave-induced heat releasing composition of the present disclosure. When the microwave-induced heat releasing film is arranged in such a manner that the microwave-induced heat releasing layer overlaps with the heat-sealed portion, the microwave-induced heat releasing layer generates heat by microwave irradiation, so that an opening is formed in the heat-sealed portion due to the shrinkage of the film. When the microwave-induced heat releasing layer is arranged at the center portion of the microwave-induced heat releasing film, an opening is easily formed at the center portion due to the rupture of the microwave-induced heat releasing film. Thus, the microwave-induced heat releasing film of the present disclosure achieves excellent adhesion to a substrate and water resistance. Since the microwave-induced heat releasing film of the present disclosure is capable of generating heat by microwave irradiation during microwave heating, an opening is easily formed in the microwave-induced heat releasing film, and thus high water vapor permeability can be achieved.

[0132] Since the microwave-induced heat releasing film of the present disclosure has the above properties, the microwave-induced heat releasing film is suitable for use as a microwave-induced heat releasing film for packaging, and can be particularly effectively used as a microwave-induced heat releasing film for water vapor permeable packaging.

[0133] <microwave-induced heat releasing package> The microwave-induced heat releasing package of the present disclosure includes the above microwave-induced heat releasing film of the present disclosure, wherein a microwave-induced heat releasing layer is formed on at least a portion of the microwave-induced heat releasing film. The microwave-induced heat releasing film can constitute the entire portion of the package body of the microwave-induced heat releasing package, or only a portion of the package body of the microwave-induced heat releasing package.

[0134] The microwave-induced heat releasing package can be selected from the embodiments commonly used for microwave-induced heat releasing sheets. The package body of the microwave-induced heat releasing package can be a double-sealed bag, a three-sealed bag, a four-sealed bag, a pillow-sealed bag, a stand-up pouch, a lap-sealed bag, an accordion bag, a heat-sealable package, a tube, a toffee bag, an overwrap package, a fin-sealed package, a dumpling package, a twist-end package, a clip-end package, a Tetra Pak (registered trademark), a gable-top package, a brick carton, a vacuum package, a cup, a tray, a bottle, a container, a box, a case, a food tray, a cover, a lid, a cap, a cover material, a label, or a paper.

[0135] The method of preparing a microwave-induced exothermic package preferably comprises forming the package using a microwave-induced exothermic film.

[0136] Forming can include shaping the microwave-induced exothermic film into a package. A sheet of microwave-induced exothermic film can be folded in half, and two edges of the folded film can be sealed to form a bag. In addition, two sheets of microwave-induced exothermic film can be stacked so that the microwave-induced exothermic layers face each other, and two edges of the stacked films can be sealed to form a bag.

[0137] Additionally, forming may include covering the container with a microwave-induced exothermic film to form a package.

[0138] For forming, any method for forming typical packaging can be used, such as double-side sealed bags, three-side sealed bags, four-side sealed bags, pillow-sealed bags, stand-up bags, lap-sealed bags, gusseted bags, melt-sealable packages, tubes, toffee packages, clip packages, fin-seal packages, dumpling packages, twist-end packages, clip-end packages, Tetra Pak (registered trademark), slant-top packages, brick cartons, vacuum packages, cups, trays, bottles, containers, boxes, cases, food trays, covers, lids, caps, covering materials, labels or papers.

[0139] Figure 6 and Figure 7 An example of the structure of the microwave-induced heat release package of the present disclosure is shown in FIG.

[0140] like Figure 6 As shown, the microwave-induced heat release package 2A comprises a lid 21 and a container 22. The microwave-induced heat release package 2A is a packaging container in which the lid 21 is sealed to a heat-sealed portion 221 of the container 22 by heat sealing.

[0141] The cover 21 may be any one of the microwave-induced heat-releasing films 1A to 1E of the present disclosure. The cover 21 may be formed such that a portion of the microwave-induced heat-releasing layer 12 is located on the heat-sealed portion 221 .

[0142] The microwave-induced heat-releasing layer 12 is arranged linearly on the lid 21, but the arrangement of the microwave-induced heat-releasing layer 12 can be adjusted according to the contents of the container 22, the internal volume of the container 22, or the shape of the container 22. The microwave-induced heat-releasing layer 12 can be circular or rectangular in shape, and the microwave-induced heat-releasing layer 12 can be provided in two or more areas of the lid 21.

[0143] The microwave-induced heat-releasing layer 12 is provided substantially at the center of the upper edge of the short side of the container 22, but the microwave-induced heat-releasing layer 12 may be provided at any portion of the heat-sealed portion.

[0144] The container 22 is essentially an inverted truncated rectangular pyramid, but may have other shapes, such as a cylinder, a cube, and a triangular prism, depending on the contents or intended use.

[0145] The container 22 has a heat-sealing portion 221 at an upper portion of the container 22. The heat-sealing portion 221 is formed as a flat surface in contact with the lid 21. The lid 21 and the container 22 are joined together at the heat-sealing portion 221.

[0146] When the microwave-induced heat-releasing package 2A is irradiated with microwaves, the microwave-induced heat-releasing layer 12 generates heat to soften the heat-sealed portion 221. As a result, an opening may be formed between the lid 21 and the container 22 due to an increase in internal pressure caused by water vapor generated by the contents including moisture. The water vapor is released from the opening.

[0147] like Figure 7 As shown, the microwave-induced heat release package 2B is a packaging container having the same structure as that of the microwave-induced heat release package 2A, except that the position of the microwave-induced heat release layer 12 is changed to a position that does not overlap with the heat-sealed portion 221 of the container 22. The microwave-induced heat release layer 12 may be disposed substantially at the center of the cover 21 along the longitudinal direction of the cover 21.

[0148] When the microwave-induced heat-releasing package 2B is irradiated with microwaves, the microwave-induced heat-releasing layer 12 generates heat, so that the portion of the lid 21 provided with the microwave-induced heat-releasing layer 12 is ruptured or softened to such an extent that the lid 21 can be ruptured by steam pressure. As a result, an opening is formed, from which water vapor generated by the contents including the mixture is released.

[0149] The microwave-induced exothermic packaging of the present disclosure includes a microwave-induced exothermic layer, wherein the microwave-induced exothermic layer includes the above-mentioned microwave-induced exothermic composition of the present disclosure. Therefore, the microwave-induced exothermic layer of the microwave-induced exothermic packaging of the present disclosure generates heat by microwave irradiation. When the microwave-induced exothermic layer is arranged to overlap with the heat-sealed portion of the microwave-induced exothermic packaging, an opening is easily formed in the heat-sealed portion because the film is shrunk by the heat generated by the microwave-induced exothermic layer. When the microwave-induced exothermic layer is arranged in the central portion of the microwave-induced exothermic packaging, an opening is easily formed in the central portion because the microwave-induced exothermic film is damaged or torn by the heat generated by the microwave-induced exothermic layer. Since heat is generated by microwave irradiation during microwave heating, openings are easily formed in the microwave-induced exothermic packaging of the present disclosure to achieve high water vapor permeability, as well as excellent adhesion to the substrate and excellent water resistance.

[0150] Since the microwave-induced heat-releasing package of the present disclosure has the above-mentioned characteristics, the microwave-induced heat-releasing package is suitable for use as a microwave-assisted heat-releasing package, such as a package for microwave heating.

[0151] Since the microwave-induced exothermic packaging of the present disclosure has excellent adhesion to a substrate and excellent water resistance as well as high water vapor permeability, the microwave-induced exothermic packaging is suitable for use in packaging in which a through-hole is formed by microwave irradiation. Further, for example, the microwave-induced exothermic packaging of the present disclosure is suitable for use in a cooking sheet in which a food is browned by microwave irradiation.

[0152] As described above, the various embodiments of the present application have been described. These embodiments are described only as examples, and the present application is not limited to these embodiments. The embodiments can be executed in various combinations, and can be omitted, replaced, or modified in the embodiments without departing from the scope of the present application. The embodiments and the modified embodiments are within the scope of the present application, and within the scope defined by the claims of the present application, and equivalents thereto.

[0153] Example Hereinafter, the present disclosure will be described by way of examples and comparative examples. The examples should not be construed as limiting the scope of the present disclosure.

[0154] <Preparation of Microwave-Induced Exothermic Composition> (Preparation Example 1) 100 parts by mass of a PEDOT:PSS solution (ORGACON S315, available from AGFA Materials Japan Co., Ltd.) including PEDOT serving as a conductive polymer and PSS serving as a dopant, 1.5 parts by mass of a styrene-butadiene copolymer (SR102, available from NIPPON A&L Co., Ltd., glass transition temperature (Tg): 21 degrees Celsius), and 30 parts by mass of ethanol were mixed, and the resulting mixture was stirred for 30 minutes to prepare a microwave-induced exothermic composition 1 in which the amount of the resin was 50 mass% with respect to the solid content of the microwave-induced exothermic composition.

[0155] (Preparation Example 2) A microwave-induced exothermic composition 2 was prepared in the same manner as in Preparation Example 1 except that 1.5 parts by mass of the styrene-butadiene copolymer (SR102, available from NIPPON A&L Co., Ltd., glass transition temperature (Tg): 21 degrees Celsius) was replaced with 1.8 parts by mass of a styrene-butadiene copolymer (LX432M, available from Zeon Co., Ltd., glass transition temperature (Tg): -58 degrees Celsius). In the microwave-induced exothermic composition 2, the amount of the resin was 50 mass% with respect to the solid content of the microwave-induced exothermic composition.

[0156] (Preparation Example 3) A microwave-induced heat-releasing composition 3 was produced in the same manner as in Production Example 1 except that 1.6 parts by mass of a styrene-butadiene copolymer (SR107, available from NIPPON A&L Co., Ltd., glass transition temperature (Tg): -15 degrees Celsius) was used instead of 1.5 parts by mass of a styrene-butadiene copolymer (SR102, available from NIPPON A&L Co., Ltd., glass transition temperature (Tg): 21 degrees Celsius). In the microwave-induced heat-releasing composition 3, the amount of the resin was 50% by mass relative to the solid content of the microwave-induced heat-releasing composition.

[0157] (Production Example 4) A microwave-induced heat-releasing composition 4 was produced in the same manner as in Production Example 1 except that the amount of the styrene-butadiene copolymer (SR102, available from NIPPON A&L Co., Ltd., glass transition temperature (Tg): 21 degrees Celsius) was changed from 1.5 parts by mass to 0.1 parts by mass. In the microwave-induced heat-releasing composition 4, the amount of the resin was 5% by mass relative to the solid content of the microwave-induced heat-releasing composition.

[0158] (Production Example 5) A microwave-induced heat-releasing composition 5 was produced in the same manner as in Production Example 1 except that the amount of the styrene-butadiene copolymer (SR102, available from NIPPON A&L Co., Ltd., glass transition temperature (Tg): 21 degrees Celsius) was changed from 1.5 parts by mass to 0.2 parts by mass. In the microwave-induced heat-releasing composition 5, the amount of the resin was 10% by mass relative to the solid content of the microwave-induced heat-releasing composition.

[0159] (Production Example 6) A microwave-induced heat-releasing composition 6 was produced in the same manner as in Production Example 1 except that the amount of the styrene-butadiene copolymer (SR102, available from NIPPON A&L Co., Ltd., glass transition temperature (Tg): 21 degrees Celsius) was changed from 1.5 parts by mass to 13.9 parts by mass. In the microwave-induced heat-releasing composition 6, the amount of the resin was 90% by mass relative to the solid content of the microwave-induced heat-releasing composition.

[0160] (Production Example 7) A microwave-induced heat-releasing composition 7 was produced in the same manner as in Production Example 1 except that the amount of the styrene-butadiene copolymer (SR102, available from NIPPON A&L Co., Ltd., glass transition temperature (Tg): 21 degrees Celsius) was changed from 1.5 parts by mass to 29.3 parts by mass. In the microwave-induced heat-releasing composition 7, the amount of the resin was 95% by mass relative to the solid content of the microwave-induced heat-releasing composition.

[0161] (Production Example 8) Microwave-induced heat releasing composition 8 was prepared in the same manner as in Production Example 1 except that a solution of polyaniline doped with 100 parts by mass of dodecylbenzenesulfonate salt (available from Sigma-Aldrich) was used instead of the PEDOT:PSS solution. In the microwave-induced heat releasing composition 8, the amount of the resin was 50 mass% relative to the solid content of the microwave-induced heat releasing composition.

[0162] (Production Example 9) Microwave-induced heat releasing composition 9 was prepared in the same manner as in Production Example 1 except that 1.5 parts by mass of a styrene-butadiene copolymer (SR102, available from NIPPON A&L Co., Ltd., glass transition temperature (Tg): 21 degrees Celsius) was replaced with 1.7 parts by mass of an acrylonitrile-butadiene copolymer (1571C2, available from Zeon Corporation, glass transition temperature (Tg): -16 degrees Celsius). In the microwave-induced heat releasing composition 9, the amount of the resin was 50 mass% relative to the solid content of the microwave-induced heat releasing composition.

[0163] (Production Example 10) Microwave-induced heat releasing composition 10 was prepared in the same manner as in Production Example 1 except that 1.5 parts by mass of a styrene-butadiene copolymer (SR102, available from NIPPON A&L Co., Ltd., glass transition temperature (Tg): 21 degrees Celsius) was replaced with 1.6 parts by mass of a vinyl acetate resin (MI-17, available from Nishin Chemical Co., Ltd., glass transition temperature (Tg): 35 degrees Celsius). In the microwave-induced heat releasing composition 10, the amount of the resin was 50 mass% relative to the solid content of the microwave-induced heat releasing composition.

[0164] (Production Example 11) Microwave-induced heat releasing composition 11 was prepared in the same manner as in Production Example 1 except that 1.5 parts by mass of a styrene-butadiene copolymer (SR102, available from NIPPON A&L Co., Ltd., glass transition temperature (Tg): 21 degrees Celsius) was replaced with 1.8 parts by mass of a silicone resin (DOWSIL RSN-0255, available from Dow Toray Co., Ltd., glass transition temperature (Tg): 56 degrees Celsius). In the microwave-induced heat releasing composition 11, the amount of the resin was 50 mass% relative to the solid content of the microwave-induced heat releasing composition.

[0165] (Production Example 12) A microwave-induced heat releasing composition 12 was prepared in the same manner as in Production Example 1 except that 1.5 parts by mass of a styrene-butadiene copolymer (SR102, available from NIPPON A&L Co., Ltd., glass transition temperature (Tg): 21 degrees Celsius) was replaced with 2.5 parts by mass of an acrylic resin (63J, available from BASF, glass transition temperature (Tg): 73 degrees Celsius). In the microwave-induced heat releasing composition 12, the amount of the resin was 50% by mass relative to the solid content of the microwave-induced heat releasing composition.

[0166] (Production Example 13) A microwave-induced heat releasing composition 13 was prepared in the same manner as in Production Example 1 except that 1.5 parts by mass of a styrene-butadiene copolymer (SR102, available from NIPPON A&L Co., Ltd., glass transition temperature (Tg): 21 degrees Celsius) was replaced with 1.5 parts by mass of a urethane resin (6820, available from Japan Coating Resin Corporation, glass transition temperature (Tg): 25 degrees Celsius). In the microwave-induced heat releasing composition 13, the amount of the resin was 50% by mass relative to the solid content of the microwave-induced heat releasing composition.

[0167] (Production Example 14) A microwave-induced heat releasing composition 14 was prepared by mixing 100 parts by mass of a PEDOT:PSS solution (ORGACON S315, available from AGFA Materials Japan Co., Ltd.) with 30 parts by mass of ethanol and stirring the resulting mixture for 30 minutes.

[0168] The conductive polymer, the dopant, and the resin included in the microwave-induced heat releasing composition of each production example are listed in Table 1.

[0169] [Table 1] <Production of Microwave-Induced Heat Releasing Film> (Examples 1 to 18 and Comparative Examples 1 to 6) A microwave-induced heat releasing composition of each production example was applied on a predetermined region of a heat-sealable PET film as a substrate. The predetermined region was a “heat-sealable portion” or a “center portion” having a predetermined size. The applied microwave-induced heat releasing composition was dried at 90 degrees Celsius for 5 minutes and then stored at 25 degrees Celsius for 24 hours, thereby producing a microwave-induced heat releasing film in which a microwave-induced heat releasing layer (coating film or coating layer) was formed on the heat-sealable PET film.

[0170] In the case where the coated area is the "heat-seal portion" of the heat-seal PET film, the microwave-induced heat-releasing composition was applied in a size of 5 cm in length and 5 cm in width when viewed horizontally, and heat-sealing was performed by arranging the microwave-induced heat-releasing layer so that the length direction (long side) of the microwave-induced heat-releasing layer overlapped with the seal portion and was perpendicular to the seal portion.

[0171] In the case where the coated area is the "center portion" of the heat-seal PET film, the microwave-induced heat-releasing composition was applied in a size of 10 cm in length and 1 cm in width when viewed horizontally, and heat-sealing was performed by arranging the microwave-induced heat-releasing layer in the center portion of the container.

[0172] Sealing was performed in the following manner. A paper towel (KIM TOWER, available from NIPPON PAPER CRECIA Co., Ltd.) soaked with 50 g of water was placed in the container formed of PP, and the container and the film to which the microwave-induced heat-releasing composition was applied were sealed together by heat-sealing at 180 degrees Celsius for 1 second.

[0173] The microwave-induced heat-releasing composition in the microwave-induced heat-releasing film used for each of the examples and comparative examples, and the area of the heat-seal PET film to which the microwave-induced heat-releasing composition was applied in each of the examples and comparative examples are listed in Table 2.

[0174] [Table 2] [Evaluation] As the evaluation of the microwave-induced heat-releasing film of each of the examples and comparative examples, the water resistance, the adhesion to the substrate, and the water vapor permeability were measured and evaluated in the following manner.

[0175] (Water Resistance) After immersing the microwave-induced heat-releasing film in water for 1 hour, and after taking the microwave-induced heat-releasing film out of the water, the surface of the microwave-induced heat-releasing layer of the microwave-induced heat-releasing film of each of the examples and comparative examples was tested by touching with a finger. The results were evaluated based on the following evaluation criteria.

[0176] ((Evaluation Criteria)) A: After immersing the microwave-induced heat-releasing film in water and taking it out of the water, when touched with a finger, the microwave-induced heat-releasing layer did not peel off from the substrate.

[0177] B: When the microwave-induced heat-releasing film was immersed in water, the microwave-induced heat-releasing layer did not peel off from the substrate, but when touched with a finger, less than 30% of the microwave-induced heat-releasing layer peeled off from the substrate with respect to the total area of the microwave-induced heat-releasing layer.

[0178] C: When the microwave-induced heat-releasing film is immersed in water, the microwave-induced heat-releasing layer does not peel off from the base, but 30% or more of the microwave-induced heat-releasing layer peels off from the base with respect to the total area of the microwave-induced heat-releasing layer when touched with a finger.

[0179] D: While the microwave-induced heat-releasing film is immersed in water, the microwave-induced heat-releasing layer peels off from the base.

[0180] (Adhesion to the base) A piece of Cellotape (registered trademark) (CT405AP-18, available from NICHIBAN Co., Ltd.) was adhered to the microwave-induced heat-releasing layer of the microwave-induced heat-releasing film of each of the examples and comparative examples. Then, the adhered Cellotape was peeled off in the following three stages to evaluate whether or not the microwave-induced heat-releasing layer peeled off based on the following evaluation criteria.

[0181] ((Peeling stage)) First: The Cellotape (registered trademark) was slowly peeled off at an angle of 180 degrees with respect to the sample.

[0182] Second: The Cellotape (registered trademark) was quickly peeled off at an angle of 180 degrees with respect to the sample.

[0183] Third: The Cellotape (registered trademark) was quickly peeled off at an angle of 90 degrees with respect to the sample.

[0184] ((Evaluation criteria)) A: In the third stage, the microwave-induced heat-releasing layer did not peel off.

[0185] B: In the third stage, the microwave-induced heat-releasing layer peeled off.

[0186] C: In the second stage, the microwave-induced heat-releasing layer peeled off.

[0187] D: In the first stage, the microwave-induced heat-releasing layer peeled off.

[0188] (Water vapor permeability) The container and the film sealed by heat sealing were heated in a microwave (RE-7500, available from Sharp Corporation) at 500 W for 120 seconds, and the water vapor permeability was evaluated based on the following evaluation criteria.

[0189] ((Evaluation criteria)) A: Steam was released from the area coated with the microwave-induced heat-releasing layer.

[0190] B: Steam was released from an area other than the area coated with the microwave-induced heat-releasing layer.

[0191] The results of evaluation of water resistance, adhesion to a substrate, and water vapor permeability of the microwave-induced exothermic layer are given in Table 3.

[0192] [Table 3] As can be seen from the results of Table 3, the microwave-induced exothermic layer of Examples 1 to 18 generates heat by microwave irradiation to form openings, so that high permeability is achieved, and excellent adhesion to a substrate and excellent water resistance are achieved, compared to the microwave-induced exothermic layers of Comparative Examples 1 to 6.

[0193] As demonstrated above, when a microwave-induced exothermic layer is formed by using a microwave-induced exothermic composition including a conductive polymer and a resin including a styrene-diene copolymer, an acrylonitrile-diene copolymer, a vinyl acetate resin, or a silicone resin, a microwave-induced exothermic film or a microwave-induced exothermic package including the microwave-induced exothermic layer can achieve excellent water resistance and excellent adhesion to a substrate, while achieving high water vapor permeability.

[0194] For example, embodiments of the present disclosure are as follows.

[0195] <1> A microwave-induced exothermic composition, comprising: a conductive polymer; and a resin selected from at least one of the group consisting of a styrene-diene copolymer, an acrylonitrile-diene copolymer, a vinyl acetate resin, and a silicone resin.

[0196] <2> A microwave-induced exothermic composition, comprising: a conductive polymer; and a resin selected from at least one of the group consisting of an acrylonitrile-diene copolymer and a silicone resin.

[0197] <3> A microwave-induced exothermic composition, comprising: a conductive polymer; and a resin selected from at least one of the group consisting of a styrene-diene copolymer, an acrylonitrile-diene copolymer, a vinyl acetate resin, and a silicone resin, wherein the glass transition temperature of the resin is -20 degrees Celsius or higher.

[0198] <4> The microwave-induced exothermic composition according to <1> or <2>, wherein the glass transition temperature of the resin is -20 degrees Celsius or higher.

[0199] <5> The microwave-induced exothermic composition according to any one of <1> to <4>, wherein the amount of the resin is 10 to 90 mass% with respect to the solid content of the microwave-induced heat releasing composition.

[0200] <6> The microwave-induced heat releasing composition according to any one of <1> to <5>, further comprising a dopant.

[0201] <7> The microwave-induced heat releasing composition according to any one of <1> to <6>, further comprising a high-boiling solvent having a boiling point of 100 to 350 degrees Celsius.

[0202] <8> A microwave-induced heat releasing layer, comprising: a conductive polymer; and a resin selected from at least one of the group consisting of a styrene-butadiene copolymer, an acrylonitrile-butadiene copolymer, a vinyl acetate resin, and a silicone resin, wherein the thickness of the microwave-induced heat releasing layer is 0.01 to 10 micrometers.

[0203] <9> A microwave-induced heat releasing film, comprising: a substrate; and a microwave-induced heat releasing layer according to <8> on at least one face of the substrate.

[0204] <10> A microwave-induced heat releasing package, comprising: a package main body comprising a microwave-induced heat releasing film according to <9>, the microwave-induced heat releasing film constituting the entire portion or a part of the package main body.

[0205] <11> A method of producing a microwave-induced heat releasing film, the method comprising: forming a microwave-induced heat releasing layer on at least one face of a substrate, the microwave-induced heat releasing layer comprising a microwave-induced heat releasing composition, and the microwave-induced heat releasing composition comprising a conductive polymer and a resin, the resin being at least one selected from the group consisting of a styrene-butadiene copolymer, an acrylonitrile-butadiene copolymer, a vinyl acetate resin, and a silicone resin.

[0206] This application is based on Japanese Patent Application No. 2023-041347 filed with Japan Patent Office on March 15, 2023, and claims priority thereto, the entire contents of which are incorporated herein by reference.

[0207] Description of Reference Numerals 1A to 1E Microwave-induced heat releasing film 11 Substrate 12 Microwave-induced heat releasing layer 13 Sealing agent 14 Sealable substrate 2A, 2B Microwave induced exothermic package 21 lid 22 container 221 heat seal portion

Claims

1. A microwave-induced exothermic composition comprising: Conductive polymers; and A resin selected from at least one member of the group consisting of styrene-butadiene copolymer, acrylonitrile-butadiene copolymer, vinyl acetate resin, and silicone resin.

2. The microwave-induced exothermic composition according to claim 1, The glass transition temperature of the resin is -20 degrees Celsius or higher.

3. The microwave-induced exothermic composition according to claim 1, The amount of the resin is 10% to 90% by mass relative to the solid content of the microwave-induced exothermic composition.

4. The microwave-induced exothermic composition according to claim 1, further comprising: dopant.

5. The microwave-induced exothermic composition according to claim 1, further comprising: A high boiling point solvent with a boiling point of 100°C to 350°C.

6. A microwave-induced heat release layer comprising: Conductive polymers; and a resin selected from at least one of the group consisting of styrene-butadiene copolymers, acrylonitrile-butadiene copolymers, vinyl acetate resins, and silicone resins, The thickness of the microwave-induced exothermic layer is 0.01 micrometers to 10 micrometers.

7. A microwave-induced exothermic film comprising: substrate; and The microwave-induced heat-releasing layer according to claim 6, which is provided on at least one surface of the substrate.

8. A microwave-induced heat release package comprising: A packaging body comprising the microwave-induced heat-releasing film according to claim 7, wherein the microwave-induced heat-releasing film constitutes the entire portion or a portion of the packaging body.

9. A method for preparing a microwave-induced exothermic film, the method comprising: forming a microwave-induced heat release layer on at least one surface of the substrate, The microwave-induced exothermic layer includes a microwave-induced exothermic composition, and The microwave-induced exothermic composition includes a conductive polymer and a resin, wherein the resin is at least one selected from the group consisting of styrene-butadiene copolymer, acrylonitrile-butadiene copolymer, vinyl acetate resin, and silicone resin.

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