Solid fuel

Abstract

To provide a solid fuel which does not solidify during heating and mixing, can be suitably prepared, and can sufficiently maintain its shape during combustion.SOLUTION: The solid fuel contains at least one compound (A) selected from the group consisting of a polyalkylene glycol having a ≤ 4 c alkylene group, an alkyl ether of a (poly) alkylene glycol having a ≤ 4 c alkylene group and an aryl ether of a (poly) alkylene glycol having a ≤ 4 c alkylene group.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a solid fuel. [Background technology]

[0002] Solid fuels, which consist of a cylindrical or prismatic solid fuel body sealed in a resin film and wrapped in an outer material such as aluminum foil, are known as fuels for heating cooked food. Solid fuels are primarily used for single-person hotpots and are widely used in tourist inns and, in recent years, in beef bowl chain restaurants and Japanese restaurants. Solid fuels can also be used as ignition agents for charcoal (wood charcoal) in barbecues.

[0003] For example, Patent Document 1 discloses a solid fuel containing 50 to 90 mass% of a specified monohydric alcohol (A), a specified polyhydric alcohol and / or water (B), and 3 to 20 mass% of a specified fatty acid salt (C), and discloses that the solid fuel has excellent storage stability and can be suitably used as a solid fuel. Patent Document 2 also discloses a solid fuel containing an alcohol (A) and a fatty acid (salt) (B), which has an alkali index of -2.0 to 1.0, a monohydric alcohol content of less than 85 mass%, and in which the total mass proportion of the fatty acid (salt) (B) consisting of the mass proportion of the fatty acid and the mass proportion of the fatty acid salt converted to fatty acid is 9 mass% or more, and which contains a fatty acid (salt) (B-1) having 18 or more carbon atoms and a fatty acid (salt) (B-2) having 17 or less carbon atoms, and the molar ratio of (B-1) / (B-2) is 0.01 or more and 70 or less, and which discloses that the solid fuel has basic properties such as ignition ability and flame force, as well as high hardness. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2023-065055 [Patent Document 2] Patent No. 7410604 Summary of the Invention [Problem to be solved by the invention]

[0005] Solid fuel is typically produced by heating in a mixing tank, mixing and neutralizing its components, and then cooling to solidify. However, it is required that the solid fuel does not solidify during heating and mixing. It is also required that the solid fuel maintain its shape during combustion. For example, even if solid fuel is burned after a certain period of time has passed since preparation without packaging, it must be able to sufficiently prevent the solid fuel itself from melting and spreading the fire. In other words, it is required that the two properties of not solidifying during heating and mixing and being able to sufficiently maintain the shape of the solid fuel during combustion are balanced.

[0006] The present invention has been made to solve the above problems, and aims to provide a solid fuel that does not solidify when heated and mixed, can be conveniently prepared, and can sufficiently maintain its shape when burned. [Means for solving the problem]

[0007] In order to achieve the above object, the present invention (1) is a solid fuel characterized by containing at least one compound (A) selected from the group consisting of polyalkylene glycols having an alkylene group with 4 or less carbon atoms, alkyl ethers of (poly)alkylene glycols having an alkylene group with 4 or less carbon atoms, and aryl ethers of (poly)alkylene glycols having an alkylene group with 4 or less carbon atoms. The (poly)alkylene glycol is at least one selected from the group consisting of alkylene glycol, dialkylene glycol, and polyalkylene glycol.

[0008] The solid fuel of the present invention does not solidify when heated and mixed, can be suitably prepared, and can adequately maintain its shape when burned. The solid fuel of the present invention can also adequately maintain its shape when burned, even when a certain period of time has passed since preparation and the solid fuel is burned without being packaged in an outer packaging material. While the reason why the solid fuel of the present invention does not solidify when heated and mixed, can be suitably prepared, and can adequately maintain its shape when burned is unclear, it is thought that the use of an alkylene group with a small number of carbon atoms and an ether group as component (A) allows for suitable adjustment of the solidification temperature, etc.

[0009] In this specification, the term "solid" refers to the properties of a solid, and is a concept that also includes a gel state.

[0010] The present invention (2) is the solid fuel of the present invention (1), in which the mass proportion of the compound (A) is 1 to 25 mass %. When the solid fuel contains two or more types of the compound (A), the above mass ratio is the total mass ratio thereof. This makes the effect of the present invention more pronounced.

[0011] The present invention (3) is the solid fuel of the present invention (1) or (2), which contains at least one monohydric alcohol (B) selected from the group consisting of methanol, ethanol, and propanol.

[0012] The present invention (4) is the solid fuel of the present invention (3), in which the mass proportion of the monohydric alcohol (B) is 70 mass % or less. When the solid fuel contains two or more kinds of the monohydric alcohol (B), the above mass ratio is the total mass ratio thereof. When the mass proportion of the monohydric alcohol (B) is 70 mass% or less, it is generally difficult to maintain the shape sufficiently during combustion, but the solid fuel of the present invention can maintain the shape sufficiently during combustion by containing the above component (A). In other words, when the mass proportion of the monohydric alcohol (B) is 70 mass% or less, it can be said that the effect of the present invention, that the shape can be maintained sufficiently during combustion, becomes remarkable.

[0013] The present invention (5) is the solid fuel according to any one of the present inventions (1) to (4), which contains a fatty acid (salt) (C). The fatty acid (salt) is a fatty acid and / or a fatty acid salt.

[0014] The present invention (6) is the solid fuel of the present invention (5), wherein the mass proportion of the fatty acid (salt) (C) calculated as fatty acid sodium is 3 to 26 mass %. In this specification, the mass percentage of the fatty acid (salt) (C) is the mass percentage of the fatty acid (salt) converted into the same number of moles of fatty acid sodium salt in 100% by mass of the solid fuel. When the solid fuel contains two or more types of fatty acid (salt) (C), the mass percentage is the total mass percentage of the mass percentages of each type converted into the same number of moles of fatty acid sodium salt.

[0015] The present invention (7) is the solid fuel according to any one of the present inventions (1) to (6), which contains water.

[0016] The present invention (8) is the solid fuel of the present invention (7), wherein the mass proportion of the water is 1 to 35 mass %. [Effects of the Invention]

[0017] The solid fuel of the present invention can be prepared conveniently and can adequately maintain its shape during combustion. DETAILED DESCRIPTION OF THE INVENTION

[0018] The solid fuel of the present invention contains at least one compound (A) selected from the group consisting of polyalkylene glycols having an alkylene group with 4 or less carbon atoms, alkyl ethers of (poly)alkylene glycols having an alkylene group with 4 or less carbon atoms, and aryl ethers of (poly)alkylene glycols having an alkylene group with 4 or less carbon atoms. Hereinafter, at least one compound (A) selected from the group consisting of polyalkylene glycols having an alkylene group with 4 or less carbon atoms, alkyl ethers of (poly)alkylene glycols having an alkylene group with 4 or less carbon atoms, and aryl ethers of (poly)alkylene glycols having an alkylene group with 4 or less carbon atoms will also be simply referred to as compound (A). Also, at least one monohydric alcohol (B) selected from the group consisting of methanol, ethanol, and propanol will also be simply referred to as monohydric alcohol (B).

[0019] Each component of the solid fuel of the present invention will be described below. In this specification, unless otherwise specified, the mass percentage of each component is the mass percentage relative to 100% by mass of the solid fuel.

[0020] (Compound (A)) The polyalkylene glycol having an alkylene group having 4 or less carbon atoms is represented by the following formula (1): HO-(AO) m -H (1) It is expressed as: In formula (1), A's are the same or different and represent alkylene groups having 4 or less carbon atoms. In other words, each A independently represents a methylene group, an ethylene group, a propylene group, or a butylene group. A's are preferably alkylene groups having 2 or more carbon atoms. A's are preferably alkylene groups having 3 or less carbon atoms. A's are more preferably ethylene or propylene groups, and even more preferably ethylene groups.

[0021] m is an integer of 3 or more, preferably 4 or more.

[0022] From the viewpoint of ensuring a suitable solidification temperature for the solid fuel, m is preferably 100 or less, more preferably 50 or less, even more preferably 30 or less, still more preferably 20 or less, even more preferably 10 or less, and particularly preferably 6 or less.

[0023] The polyalkylene glycol having an alkylene group with 4 or less carbon atoms preferably has an average molecular weight of 200 or more. The average molecular weight is preferably 2000 or less, and more preferably 1500 or less. In this specification, the average molecular weight is a number average molecular weight calculated from the hydroxyl value (KOH mg / g).

[0024] The alkyl ether of a (poly)alkylene glycol having an alkylene group having 4 or less carbon atoms may be a monoalkyl ether or a dialkyl ether of the (poly)alkylene glycol. The alkyl ether of the (poly)alkylene glycol having an alkylene group having 4 or less carbon atoms is represented by the following formula (2): R 2 O-(R 1 O) n -R 3 (2) It is expressed as:

[0025] In formula (2), R 1 are the same or different and represent an alkylene group having 4 or less carbon atoms. 1 R each independently represents a methylene group, an ethylene group, a propylene group, or a butylene group. 1 is preferably an alkylene group having two or more carbon atoms. 1 is preferably an alkylene group having 3 or less carbon atoms. 1 is more preferably an ethylene group or a propylene group, and even more preferably an ethylene group. n is an integer of 1 or greater. n is preferably 100 or less, more preferably 10 or less, even more preferably 3 or less, and even more preferably 2 or less. n is particularly preferably 1.

[0026] R 2represents a hydrogen atom or an alkyl group. The alkyl group has one or more carbon atoms. The number of carbon atoms is preferably 18 or less, more preferably 12 or less, and even more preferably 6 or less. The alkyl group is preferably, for example, a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, or a hexyl group. R 3 represents an alkyl group. The alkyl group is R 2 It is the same as the alkyl group in

[0027] The aryl ether of a (poly)alkylene glycol having an alkylene group having 4 or less carbon atoms may be a monoaryl ether or diaryl ether of the (poly)alkylene glycol. The aryl ether of the (poly)alkylene glycol having an alkylene group having 4 or less carbon atoms is represented by the following formula (3): R 5 O-(R 4 O) n -R 6 (3) It is expressed as:

[0028] In formula (3), R 4 , n are R in formula (2), 1 , similar to n. R 5 represents a hydrogen atom or an aryl group. The aryl group usually has 4 or more carbon atoms, preferably 5 or more, and more preferably 6 or more. The number of carbon atoms is preferably 18 or less, more preferably 12 or less, and even more preferably 8 or less. The aryl group is particularly preferably a phenyl group. R 6 represents an aryl group. The aryl group is R 5 The aryl group is the same as the aryl group in

[0029] Among these, the compound (A) is preferably a polyalkylene glycol having an alkylene group with 4 or less carbon atoms, or an alkyl ether of a (poly)alkylene glycol having an alkylene group with 4 or less carbon atoms, more preferably a polyalkylene glycol having an alkylene group with 4 or less carbon atoms, or an alkyl ether of an alkylene glycol having an alkylene group with 4 or less carbon atoms, and even more preferably a polyalkylene glycol having an alkylene group with 4 or less carbon atoms.

[0030] In 100% by mass of the solid fuel of the present invention, the mass proportion of the compound (A) is preferably 1% by mass or more, more preferably 2% by mass or more, and is preferably 50% by mass or less, more preferably 40% by mass or less, even more preferably 35% by mass or less, and particularly preferably 30% by mass or less. Here, the mass proportion of the compound (A) means the total mass proportion when the solid fuel contains two or more types of compound (A). The same applies to the mass proportions of other components.

[0031] (Monohydric alcohol (B)) The solid fuel of the present invention preferably contains at least one monohydric alcohol (B) selected from the group consisting of methanol, ethanol, and propanol. The monohydric alcohol (B) is preferably methanol or ethanol, and more preferably methanol. The propanol may be n-propanol or isopropanol.

[0032] The monohydric alcohol (B) functions as a combustion component, and the higher its mass proportion in the solid fuel, the more improved its ignition ability and shape stability. On the other hand, from the viewpoint of improving the weight retention of the solid fuel during storage, the mass proportion is preferably 95 mass% or less, more preferably 85 mass% or less, and even more preferably 70 mass% or less. The monohydric alcohol (B) may be used alone or in combination of two or more kinds.

[0033] The mass proportion of the monohydric alcohol (B) (particularly preferably methanol) is preferably 50 to 95 mass% of 100 mass% of the solid fuel in order to improve ignition performance. For example, from the viewpoint of improving the weight retention of the solid fuel during storage while maintaining sufficient ignition performance, the mass proportion is more preferably 50 mass% or more and 70 mass% or less. The mass proportion is further preferably 55 mass% or more, even more preferably 60 mass% or more, and particularly preferably 65 mass% or more. The above-mentioned preferred mass proportion range of the monohydric alcohol (B) can be interpreted as the preferred mass proportion range of methanol alone.

[0034] In the solid fuel of the present invention, the mass ratio ((A) / (B)) of the compound (A) to the monohydric alcohol (B) (particularly preferably methanol) is preferably 0.01 or more, more preferably 0.02 or more. Moreover, the mass ratio ((A) / (B)) is preferably 2 or less, more preferably 1 or less, and even more preferably 0.8 or less.

[0035] In 100% by mass of the solid fuel of the present invention, the total mass ratio of the compound (A) and the monohydric alcohol (B) (particularly preferably methanol) is preferably 40% by mass or more, more preferably 50% by mass or more, and even more preferably 60% by mass or more. Moreover, the total mass ratio is preferably 98% by mass or less, more preferably 95% by mass or less, and even more preferably 93% by mass or less.

[0036] (Fatty Acid (Salt) (C)) The fatty acid (salt) (C) usually has 2 or more carbon atoms, preferably 8 or more carbon atoms, and preferably 22 or less carbon atoms, more preferably 20 or less carbon atoms. In this specification, the fatty acid (salt) (C) is a fatty acid and / or a fatty acid salt, preferably a fatty acid salt. The fatty acid (salt) (C) is preferably a salt formed by, for example, a neutralization reaction between a fatty acid and an alkali. When a fatty acid is neutralized with an alkali to become a fatty acid salt, sufficient solidification properties are exhibited. The fatty acid (salt) (C) may be used alone or in combination of two or more, but it is preferable to use two or more in combination. For example, it is more preferable to use two or more fatty acids (salts) with different carbon numbers from fatty acids (salts) with 2 to 22 carbon atoms in combination, and it is even more preferable to use two or more fatty acids (salts) with different carbon numbers from fatty acids (salts) with 8 to 20 carbon atoms in combination.

[0037] The fatty acid of the fatty acid (salt) (C) is not particularly limited, but examples thereof include saturated fatty acids such as acetic acid, caprylic acid, octylic acid, capric acid, lauric acid, myristic acid, palmitic acid, stearic acid, arachidic acid, behenic acid, pentadecylic acid, and margaric acid; and unsaturated fatty acids such as palmitoleic acid, oleic acid, linoleic acid, linolenic acid, and arachidonic acid. These may be used alone, but it is preferable to use two or more of them in combination. Among these, saturated fatty acids are preferred from the viewpoint of solidification stability, and fatty acids having 8 to 22 carbon atoms are also preferred, and at least one selected from the group consisting of caprylic acid, octylic acid, capric acid, lauric acid, myristic acid, palmitic acid, stearic acid, arachidic acid, pentadecylic acid, and margaric acid is more preferred.

[0038] The salt of the fatty acid (salt) (C) is not particularly limited, but examples thereof include sodium salts and potassium salts. These may be used alone or in combination of two or more. Among these, sodium salts are preferred because of their stability in solidification.

[0039] For example, the fatty acid (salt) (C) preferably includes a fatty acid (salt) (C-1) having 18 or more carbon atoms and a fatty acid (salt) (C-2) having 17 or less carbon atoms, and the mass ratio of (C-1) in terms of fatty acid sodium salt) / (C-2) in terms of fatty acid sodium salt) is 0.1 or more and 10 or less. In this specification, the fatty acid sodium equivalent value refers to the value (mass) obtained by converting a fatty acid (salt) into the same number of moles of fatty acid sodium. The mass ratio of (C-1) in terms of fatty acid sodium content / (C-2) in terms of fatty acid sodium content is more preferably 0.2 or more. The mass ratio of (C-1) in terms of fatty acid sodium content / (C-2) in terms of fatty acid sodium content is more preferably 5 or less, and even more preferably 3 or less.

[0040] The fatty acid (salt) (C) preferably contains a fatty acid (salt) (C-1') having 18 to 22 carbon atoms and a fatty acid (salt) (C-2') having 2 to 17 carbon atoms, and the mass ratio of (C-1') in terms of fatty acid sodium salt) / (C-2') in terms of fatty acid sodium salt) is more preferably 0.1 or more and 10 or less. The preferred range of the mass ratio of ((C-1') in terms of fatty acid sodium) / ((C-2') in terms of fatty acid sodium) is the same as the preferred range of the mass ratio of ((C-1) in terms of fatty acid sodium) / ((C-2) in terms of fatty acid sodium) described above.

[0041] In one preferred embodiment of the present invention, the fatty acid (salt) (C) contains a fatty acid (salt) (C-1A') having 21 to 22 carbon atoms. It is more preferable that the fatty acid (salt) (C-1B') contains a fatty acid (salt) having 18 to 20 carbon atoms and a fatty acid (salt) (C-1A') contains a fatty acid (salt) having 21 to 22 carbon atoms. It is further preferable that the mass ratio of (C-1B') converted into fatty acid sodium content / (C-1A') converted into fatty acid sodium content) is 1 or more and 3 or less.

[0042] When the solid fuel of the present invention contains the fatty acid (salt) (C), the mass proportion of the fatty acid (salt) (C) converted to fatty acid sodium is preferably 3 to 26 mass % in 100 mass % of the solid fuel. When the mass proportion of the fatty acid (salt) (C) converted to fatty acid sodium is 26 mass% or less, the temperature at which the solid fuel solidifies can be lowered. Also, when the mass proportion of the fatty acid (salt) (C) converted to fatty acid sodium is 3 mass% or more, more sufficient solidification can be obtained, and the shape of the solid fuel during combustion tends to be better. The mass proportion of the fatty acid (salt) (C) converted to fatty acid sodium is preferably 22 mass% or less, more preferably 20 mass% or less, even more preferably 16 mass% or less, even more preferably 14 mass% or less, and particularly preferably 13 mass% or less.

[0043] The solid fuel may further contain a polyhydric alcohol. The polyhydric alcohol functions as an auxiliary component (auxiliary combustion component) of the monohydric alcohol (B). In this specification, the polyhydric alcohol refers to a dihydric or higher alcohol that is not a polymer (for example, one with a molecular weight of 300 or less). The polyhydric alcohol is preferably at least one selected from the group consisting of ethylene glycol, diethylene glycol, propylene glycol, and glycerin. The polyhydric alcohols may be used alone or in combination of two or more kinds.

[0044] The polyhydric alcohol is preferably ethylene glycol and / or diethylene glycol from the viewpoint of ignition ability and maintaining the shape of the solid fuel during combustion, and more preferably ethylene glycol from the viewpoint of reducing odor during combustion.

[0045] In terms of improving ignition performance, the mass proportion of polyhydric alcohol in 100% by mass of solid fuel is preferably 40% by mass or less, more preferably 30% by mass or less, and even more preferably 20% by mass or less. The mass proportion of polyhydric alcohol may be 0% by mass.

[0046] In another preferred embodiment of the present invention, the solid fuel of the present invention contains a monohydric alcohol (B) (particularly preferably methanol) and a polyhydric alcohol.

[0047] The mass proportion of alcohol in 100 mass% of the solid fuel is preferably 50 to 99 mass%. The alcohol is at least one selected from the group consisting of monohydric alcohol (B), monohydric alcohols other than the monohydric alcohol (B), and polyhydric alcohols. The mass proportion of the alcohol is more preferably 60 mass % or more, and even more preferably 65 mass % or more. The mass proportion of the alcohol is more preferably 90 mass % or less, and even more preferably 80 mass % or less.

[0048] The solid fuel may contain a thickener, which tends to suppress scattering of powder particles during combustion and further improve the stability of solidification. The thickeners may be used alone or in combination of two or more.

[0049] The thickener is not particularly limited, but examples thereof include polysaccharides, polyacrylamide, polyacrylic acid and its salts, polyvinyl alcohol, etc. Among these, polysaccharides are preferred because they suppress the scattering of particulate fuel during combustion. In other words, it is preferable that the thickener contains a polysaccharide.

[0050] Examples of polysaccharides include, but are not limited to, cellulose derivatives, starch, alginic acid and its salts (for example, sodium alginate), guar gum, gellan gum, gelatin, pectin, xanthan gum, and carrageenan.

[0051] The mass proportion of the thickener in 100 mass% of the solid fuel is preferably 1.0 mass% or less, more preferably 0.8 mass% or less, and even more preferably 0.5 mass% or less. The mass proportion of the thickener may be 0 mass%. The above compounds (A), alcohols such as monohydric alcohols (B), and fatty acids (salts) (C) are not included in the mass proportion of the thickener.

[0052] In addition to the above components, the solid fuel may contain additives commonly used in solid fuels. Examples of additives include flavorings, coloring powders, and stabilizers. These additives may be used alone or in combination of two or more. Furthermore, when preparing the solid fuel, a neutralizing agent such as sodium hydroxide may be used to neutralize the fatty acids.

[0053] The solid fuel preferably contains water. When the solid fuel contains water, the mass proportion of water is preferably 0.1 mass% or more, more preferably 0.2 mass% or more, and even more preferably 0.3 mass% or more, based on 100 mass% of the solid fuel. The mass proportion of water is preferably 40 mass% or less, more preferably 35 mass% or less, even more preferably 30 mass% or less, and particularly preferably 25 mass% or less. When the mass proportion of water is 30 mass% or less, the ignition ability and solidification ability tend to be better. The mass proportion of water mentioned above includes the amount of water generated by neutralization of the alkaline agent and the acid agent such as fatty acid.

[0054] The solid fuel can be produced by a conventional method, such as by mixing and neutralizing the components while heating them in a blending tank, and then cooling and solidifying them. When the solid fuel contains alcohol, the liquid alcohol is usually solidified by blending a fatty acid and an alkali into the solid fuel composition, and the fatty acid is neutralized with the alkali to form a fatty acid salt, thereby obtaining sufficient solidification properties and enabling the solid fuel composition to be made into a solid solid fuel. Note that a solid fuel in the form of a block or a tall cylinder may be formed into a predetermined shape (such as a short cylinder) by cutting or the like.

[0055] The surface of the solid fuel may be covered with paraffin. For example, the solid fuel may be sealed with paraffin. When the surface of the solid fuel is covered with paraffin, evaporation of the fuel components of the solid fuel can be prevented, and better weight retention tends to be obtained. In addition, the solid fuel tends to have the ignition ability required for a fuel, while preventing unintentional ignition of the solid fuel, resulting in a safer solid fuel. In addition, the shape of the solid fuel during combustion tends to be better.

[0056] The paraffin is not particularly limited as long as it is a hydrocarbon, and examples thereof include chain saturated hydrocarbons such as hexadecane, heptadecane, octadecane, nonadecane, icosane, henicosane, docosane, tricosane, tetracosane, pentacosane, hexacosane, heptacosane, octacosane, nonacosane, etc. These may be used alone or in combination of two or more.

[0057] The method for covering the surface of the solid fuel with paraffin is not particularly limited, but can be, for example, a method of spraying liquid paraffin onto the surface of the solid fuel, or a method of immersing the surface in heated and dissolved liquid paraffin.

[0058] The shape of the solid fuel is not particularly limited, but examples thereof include a cylindrical shape, a prismatic shape, a lump shape, a powder shape, etc. Among these, a cylindrical shape and a prismatic shape are preferred from the viewpoint of ignition stability.

[0059] The solid fuel may be packaged in an outer packaging material such as aluminum foil, or may not be packaged; however, it is preferable that the solid fuel is not packaged in an outer packaging material, as this has a significant effect of maintaining its shape during combustion. The solid fuel may be filled in a can. For example, a product form is envisioned in which the solid fuel is filled in a can, and the lid is opened while the can is still in the can to ignite the solid fuel and use it as fuel.

[0060] The solid fuel can be used for keeping food such as cooked food warm, heating it, cooking it, etc. Among these, it is preferably used for keeping food warm or heating it.

[0061] The weight of the solid fuel is not particularly limited and may be appropriately set depending on the purpose of use, etc. If it is used for keeping cooked food warm or heating it, the weight is preferably 3 to 300 g, more preferably 3 to 60 g, and even more preferably 5 to 50 g. In this specification, when the solid fuel is packaged in an outer packaging material or the surface of the solid fuel is covered with paraffin, the weight (mass) of the outer packaging material or the weight (mass) of the paraffin is not included in the weight (mass) of the solid fuel.

[0062] When burning the solid fuel, the solid fuel is placed inside the tray and ignited to burn. This type of solid fuel is suitable for keeping hot food, such as hot pot dishes, warm after cooking has already been completed. [Example]

[0063] The present invention will be specifically described based on examples, but the present invention is not limited to these examples.

[0064] The various chemicals used in the examples and comparative examples will be collectively described below. Methanol: Methanol manufactured by Yoneyama Pharmaceutical Co., Ltd. Ethanol: Ethanol (99.5) manufactured by Yoneyama Pharmaceutical Co., Ltd. Isopropanol: 2-propanol manufactured by Yoneyama Pharmaceutical Co., Ltd. Ethylene glycol: Ethylene glycol manufactured by Yoneyama Pharmaceutical Co., Ltd. Sodium stearate: Stearic acid manufactured by Tokyo Chemical Industry Co., Ltd. neutralized with liquid caustic soda (48%) manufactured by AGC Corporation Sodium palmitate: Palmitic acid manufactured by Tokyo Chemical Industry Co., Ltd. neutralized with liquid caustic soda (48%) manufactured by AGC Corporation Sodium octylate: 2-ethylhexanoic acid manufactured by Tokyo Chemical Industry Co., Ltd. neutralized with liquid caustic soda (48%) manufactured by AGC Corporation Sodium laurate: Lauric acid manufactured by Tokyo Chemical Industry Co., Ltd. neutralized with liquid caustic soda (48%) manufactured by AGC Corporation Sodium behenate: Behenic acid manufactured by Tokyo Chemical Industry Co., Ltd., neutralized with liquid caustic soda (48%) manufactured by AGC Corporation. Sodium acetate: Acetic acid manufactured by Tokyo Chemical Industry Co., Ltd. neutralized with liquid caustic soda (48%) manufactured by AGC Corporation Diethylene glycol monobutyl ether: Butycenol 20P manufactured by KH Neochem Co., Ltd. Propylene glycol methyl ether: Dowanol PM from The Dow Chemical Company 3-Methoxy-3-methyl-1-butanol: Solfit manufactured by Kuraray Co., Ltd. Methyl glycol: Nippon Nyukazai Co., Ltd. Isobutyl glycol: Nippon Nyukazai Co., Ltd. Hexyl glycol: Nippon Nyukazai Co., Ltd. Phenyl glycol: Nippon Nyukazai Co., Ltd. Diethylene glycol monophenyl ether: Nippon Nyukazai Co., Ltd. Dimethyldiglycol: Nippon Nyukazai Co., Ltd. PEG200: NOF Corporation, polyethylene glycol with an average molecular weight of 200 PEG300: NOF Corporation, polyethylene glycol with an average molecular weight of 300 PEG400: NOF Corporation, polyethylene glycol with an average molecular weight of 400 PPG250: Polypropylene glycol with an average molecular weight of 250, manufactured by NOF Corporation PPG400: Polypropylene glycol with an average molecular weight of 400, manufactured by NOF Corporation PPG700: Polypropylene glycol with an average molecular weight of 700, manufactured by NOF Corporation PBG500: Polybutylene glycol with an average molecular weight of 500, manufactured by NOF Corporation PBG700: Polybutylene glycol with an average molecular weight of 700, manufactured by NOF Corporation PEG-PPG-PEG (average molecular weight 1100): NOF Corporation PEG-PPG-PEG (average molecular weight 1300): NOF Corporation

[0065] Examples and Comparative Examples <Production of solid fuel> According to the formulations shown in Tables 1 to 4, each chemical was mixed using a hot stirrer at 55 to 70°C to obtain a solid fuel composition. Here, in each formulation, fatty acids and sodium hydroxide were blended so that the fatty acid salts had the compositions shown in Tables 1 to 4. The mass (parts by mass) of each component is the mass of the pure content. The total amount was 100 parts by mass. The resulting solid fuel composition was cooled and solidified, and then cut and molded into a cylindrical shape to obtain a solid fuel. The solid fuel obtained was subjected to the following evaluations, and the results are shown in Tables 1 to 4.

[0066] (Gel point (solidification temperature)) This is the temperature at which the mixture solidifies after being cooled and mixed under heat. A lower temperature is preferable to prevent solidification during mixing under heat. The decimal points are rounded off. The evaluation was based on the following criteria. ◎: Below 59℃ ○: 60℃~63℃ △: 64℃~66℃ ×: 67℃ or higher If it is rated as fair or better, it is considered good.

[0067] (Ignitability) The flame of an ignition lighter was applied to the top surface of the solid fuel, and the time until it ignited was measured. More highly rated. 〇: Ignition time is less than 1 second △: Ignition time is between 1 and 2 seconds ×: Does not ignite even after 2 seconds of flame exposure If it is rated as fair or better, it is considered good.

[0068] (Prevents melting during combustion) The solid fuel was ignited, solidified, and then the burning state was visually observed after the weight had decreased by 10%. Evaluation was made according to the following criteria. ◎: Burns while maintaining its shape perfectly 〇: Shape is distorted by 20% or less △: Over 20% and less than 50% of the shape is lost ×: Over 50% loss of shape If it is rated as fair or better, it is considered good.

[0069] [Table 1]

[0070] [Table 2]

[0071] [Table 3]

[0072] [Table 4]

[0073] From Tables 1 to 4, it was found that the solid fuel containing the specified compound (A) did not solidify when heated and mixed, could be suitably prepared, and could adequately maintain its shape when burned.

Claims

1. A solid fuel characterized by containing at least one compound (A) selected from the group consisting of polyalkylene glycols having an alkylene group with 4 or less carbon atoms, alkyl ethers of (poly)alkylene glycols having an alkylene group with 4 or less carbon atoms, and aryl ethers of (poly)alkylene glycols having an alkylene group with 4 or less carbon atoms.

2. 2. The solid fuel according to claim 1, wherein the mass proportion of the compound (A) is 1 to 25 mass %.

3. 3. The solid fuel according to claim 1, further comprising at least one monohydric alcohol (B) selected from the group consisting of methanol, ethanol, and propanol.

4. 4. The solid fuel according to claim 3, wherein the mass proportion of the monohydric alcohol (B) is 70 mass% or less.

5. The solid fuel according to claim 1 or 2, which contains a fatty acid (salt) (C).

6. 6. The solid fuel according to claim 5, wherein the mass ratio of the fatty acid (salt) (C) converted to fatty acid sodium is 3 to 26 mass %.

7. The solid fuel according to claim 1 or 2, which contains water.

8. 8. The solid fuel according to claim 7, wherein the mass ratio of the water is 1 to 35 mass %.

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