solid fuels

Abstract

To provide a solid fuel excellent in storage stability and suitably usable as the solid fuel.SOLUTION: A solid fuel comprises: at least one monohydric alcohol (A) selected from a group consisting of methanol, ethanol, and propanol; at least one polyhydric alcohol selected from the group consisting of ethylene glycol, diethylene glycol, propylene glycol, and glycerin, and / or water (B); and a fatty acid salt (C) having 12 to 22 carbon atoms, wherein content of the monohydric alcohol (A) is 50 to 90 mass%, and the content of the fatty acid salt (C) is 3 to 20 mass%.SELECTED DRAWING: None

Description

[Technical Field]

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

[0002] BACKGROUND ART As a fuel for heating cooked food and the like, a solid fuel is known in which a cylindrical or prismatic solid fuel body is sealed in a resin film and packaged in an outer packaging material.

[0003] For example, Patent Document 1 discloses that the volatilization of fuel components can be suppressed by covering the surface of solid fuel with polyethylene, while Patent Document 2 discloses that the volatilization of fuel components can be suppressed and storage stability can be improved by blending a fatty acid ester of a polyhydric alcohol with the solid fuel without covering its surface. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 1-267133 [Patent Document 2] Japanese Patent Application Publication No. 8-231970 Summary of the Invention [Problem to be solved by the invention]

[0005] As a result of intensive research by the present inventors, it was found that in a method of covering the surface of a solid fuel with a protective layer such as polyethylene, the protective layer may be damaged or peeled off during storage, etc., and that there is room for improvement in storage stability. It was also found that in a method of blending a fatty acid ester of a polyhydric alcohol without covering the surface of the solid fuel, there is also room for improvement in storage stability.

[0006] The present invention has been made to solve the above problems, and an object of the present invention is to provide a solid fuel that has excellent storage stability and can be suitably used as a solid fuel. [Means for solving the problem]

[0007] In order to achieve the above object, the solid fuel of the present invention comprises at least one monohydric alcohol (A) selected from the group consisting of methanol, ethanol, and propanol, at least one polyhydric alcohol and / or water (B) selected from the group consisting of ethylene glycol, diethylene glycol, propylene glycol, and glycerin, and a fatty acid salt (C) having 12 to 22 carbon atoms, wherein the content of the monohydric alcohol (A) is 50 to 90 mass %, and the content of the fatty acid salt (C) is 3 to 20 mass %. The solid fuel of the present invention has excellent storage stability and can be suitably used as a solid fuel. The reason why such effects are obtained in the present invention is not clear, but is presumed to be as follows. If the content of the monohydric alcohol (A) is reduced to the above-mentioned specific amount, the required flame intensity for a solid fuel is usually not obtained, or good solidification properties are not obtained, causing the solid fuel to liquefy during combustion and spread to unintended areas, or it is not possible to solidify it at all. However, by reducing the content of the monohydric alcohol (A) and blending the polyhydric alcohol and / or water (B), excellent storage stability is achieved, and the required flame intensity for a solid fuel and good solidification properties are also obtained. Furthermore, by containing a specific amount of the monohydric alcohol (A), the polyhydric alcohol and / or water (B), and a specific amount of the fatty acid salt (C), a suitable solid fuel can be obtained even when the content of the monohydric alcohol (A) is low. Furthermore, in the present invention, compared to the method of blending a fatty acid ester of a polyhydric alcohol, fuel evaporation can be more effectively suppressed, improving storage stability, while at the same time maintaining the performance of a solid fuel, such as ignition ability and solidification ability. In this specification, the term "solid" refers to the properties of a solid, and is a concept that also includes a gel state.

[0008] The solid fuel of the present invention preferably has a polyhydric alcohol content of 1 to 40 mass %. This makes the effect of the present invention more pronounced.

[0009] The solid fuel of the present invention preferably has a water content of 1 to 40 mass %. This makes the effect of the present invention more pronounced.

[0010] The solid fuel of the present invention preferably contains a thickener, and more preferably the thickener contains a polysaccharide. This also helps prevent powder from scattering during combustion.

[0011] The surface of the solid fuel of the present invention is preferably covered with paraffin, and the thickness of the paraffin is more preferably 0.1 to 2.0 mm. This more effectively prevents the vaporization of fuel components, making the effects of the present invention more pronounced. In addition, the solid fuel has the ignition properties required for a fuel, while preventing unintentional ignition, making it a safer solid fuel.

[0012] In the solid fuel of the present invention, the fatty acid salt (C) is preferably a fatty acid salt having 16 to 20 carbon atoms. This makes it possible to more suitably obtain a solid fuel, and the effects of the present invention become more pronounced.

[0013] In the solid fuel of the present invention, the monohydric alcohol (A) is methanol, the polyhydric alcohol and / or water (B) is ethylene glycol and / or diethylene glycol, and water; the fatty acid salt (C) is a stearate, It is preferable that the composition further contains methylcellulose. This makes the effects of the present invention more pronounced, and the composition is particularly excellent in terms of solidification, flame intensity, odor during combustion, and shape during combustion. [Effects of the Invention]

[0014] The solid fuel of the present invention has excellent storage stability and can be suitably used as a solid fuel. DETAILED DESCRIPTION OF THE INVENTION

[0015] The solid fuel of the present invention comprises at least one monohydric alcohol (A) selected from the group consisting of methanol, ethanol, and propanol, at least one polyhydric alcohol (B) selected from the group consisting of ethylene glycol, diethylene glycol, propylene glycol, and glycerin and / or water, and a fatty acid salt (C) having 12 to 22 carbon atoms, wherein the content of the monohydric alcohol (A) is 50 to 90 mass %, and the content of the fatty acid salt (C) is 3 to 20 mass %. Each component will be described below.

[0016] (Monohydric alcohol (A)) The monohydric alcohol (A) is at least one alcohol selected from the group consisting of methanol, ethanol, and propanol. The monohydric alcohol (A) functions as a combustion component, and the higher the content, the better the ignition ability, flame strength, and shape stability. However, if the content exceeds 90 mass %, the storage stability decreases. The monohydric alcohol (A) may be used alone or in combination of two or more kinds.

[0017] The monohydric alcohol (A) is preferably at least one alcohol selected from the group consisting of methanol and ethanol, more preferably methanol, for reasons of shape stability during combustion and odor suppression.

[0018] The content of the monohydric alcohol (A) is 50 to 90% by mass relative to 100% by mass of the solid fuel. If it is less than 50% by mass, sufficient flame strength and ignition ability cannot be obtained, and if it exceeds 90% by mass, sufficient storage stability cannot be obtained. The content of the monohydric alcohol (A) is preferably 55% by mass or more, more preferably 60% by mass or more, even more preferably 65% ​​by mass or more, particularly preferably 68% by mass or more, and preferably 85% by mass or less, more preferably 80% by mass or less, even more preferably 75% by mass or less, particularly preferably 73% by mass or less, and most preferably less than 70% by mass. Here, the content of the monohydric alcohol (A) means the total content when two or more types of monohydric alcohol (A) are contained. The same applies to the contents of other components.

[0019] (Polyhydric alcohol and / or water (B)) The polyhydric alcohol and / or water (B) is at least one polyhydric alcohol and / or water selected from the group consisting of ethylene glycol, diethylene glycol, propylene glycol, and glycerin. By blending the polyhydric alcohol and / or water (B) with the monohydric alcohol (A), excellent storage stability is achieved and the appropriate flame intensity required for a solid fuel is also obtained. The polyhydric alcohol and / or water (B) may be used alone or in combination of two or more kinds.

[0020] As the polyhydric alcohol and / or water (B), a polyhydric alcohol is preferred because it has excellent fire strength, storage stability, and ignition properties, and it is more preferable to use a polyhydric alcohol and water in combination because it provides good solidification properties and also provides appropriate combustibility.

[0021] The polyhydric alcohol is preferably at least one alcohol selected from the group consisting of ethylene glycol and diethylene glycol, from the viewpoint of ignition ability and continuity of combustion, and more preferably ethylene glycol, from the viewpoint of reducing odor during combustion.

[0022] The content of polyhydric alcohol and / or water (B) is preferably 1% by mass or more, more preferably 3% by mass or more, even more preferably 5% by mass or more, particularly preferably 10% by mass or more, and most particularly preferably 15% by mass or more, and is preferably 40% by mass or less, more preferably 35% by mass or less, even more preferably 30% by mass or less, and particularly preferably 25% by mass or less, based on 100% by mass of the solid fuel. If it is less than 1% by mass, sufficient storage stability tends to be insufficient, and if it exceeds 40% by mass, sufficient flame force, ignition ability, and continuity of combustion tend to be insufficient.

[0023] The content of the polyhydric alcohol is preferably 1% by mass or more, more preferably 2% by mass or more, even more preferably 5% by mass or more, particularly preferably 8% by mass or more, and is preferably 40% by mass or less, more preferably 35% by mass or less, even more preferably 30% by mass or less, particularly preferably 25% by mass or less, most preferably 20% by mass or less, and most preferably 15% by mass or less, based on 100% by mass of the solid fuel. If the content is less than 1% by mass, sufficient storage stability tends to be insufficient, and if it exceeds 40% by mass, sufficient flame force, ignition ability, and continuity of combustion tend to be insufficient.

[0024] The water content is preferably 1% by mass or more, more preferably 3% by mass or more, even more preferably 5% by mass or more, particularly preferably 8% by mass or more, and is preferably 40% by mass or less, more preferably 35% by mass or less, even more preferably 30% by mass or less, particularly preferably 25% by mass or less, most preferably 20% by mass or less, and most preferably 15% by mass or less, based on 100% by mass of the solid fuel. If the water content is less than 1% by mass, sufficient storage stability tends to be insufficient, and if the water content exceeds 40% by mass, sufficient flame strength and ignition ability, and sufficient solidification ability tend to be insufficient.

[0025] (Fatty Acid Salt (C)) The fatty acid salt (C) is a fatty acid salt having 12 to 22 carbon atoms. The fatty acid salt (C) is, for example, a salt formed by the neutralization reaction between a fatty acid and an alkali, and exhibits sufficient solidification properties when the fatty acid is neutralized with an alkali to become the fatty acid salt. The fatty acid salt (C) may be used alone or in combination of two or more kinds.

[0026] The fatty acid salt has 12 to 22 carbon atoms, and preferably 16 to 20 carbon atoms.

[0027] The fatty acid of the fatty acid salt (C) is not particularly limited, but examples thereof include saturated fatty acids such as lauric acid, myristic acid, stearic acid, palmitic acid, behenic acid, pentadecylic acid, margaric acid, and arachidic acid; and unsaturated fatty acids such as palmitoleic acid, oleic acid, linoleic acid, linolenic acid, and arachidonic acid. These may be used alone or in combination of two or more. Among these, saturated fatty acids are preferred from the viewpoint of solidification stability, and at least one selected from the group consisting of lauric acid, myristic acid, stearic acid, palmitic acid, and behenic acid is more preferred, with stearic acid and palmitic acid being even more preferred, and stearic acid being particularly preferred.

[0028] 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.

[0029] The content of fatty acid salt (C) is 3 to 20% by mass based on 100% by mass of the solid fuel. If the content of fatty acid salt (C) is more than 20% by mass or less than 3% by mass, sufficient solidification properties cannot be obtained and the shape upon combustion is also poor. The content of fatty acid salt (C) is preferably 4% by mass or more, more preferably 5% by mass or more, even more preferably 6% by mass or more, particularly preferably 8% by mass or more, and preferably 18% by mass or less, more preferably 16% by mass or less, even more preferably 14% by mass or less, particularly preferably 12% by mass or less.

[0030] The solid fuel preferably contains 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.

[0031] The thickener is not particularly limited, but examples thereof include polysaccharides, polyacrylamides, polyalkylene oxides, polyacrylic acids and their salts, polyvinyl alcohols, etc. Among these, polysaccharides are preferred because they suppress the scattering of particulate fuel during combustion. In other words, it is preferred that the thickener contains a polysaccharide.

[0032] The polysaccharide is not particularly limited, but examples thereof include cellulose derivatives, starch, alginic acid and its salts (e.g., sodium alginate), guar gum, gellan gum, gelatin, pectin, xanthan gum, carrageenan, etc. Among these, cellulose derivatives are preferred because they suppress the scattering of particulate fuel during combustion. In other words, it is preferable that the thickener contains a cellulose derivative.

[0033] The cellulose derivative is not particularly limited, but examples thereof include cellulose ethers such as methyl cellulose, carboxymethyl cellulose, carboxyethyl cellulose, hydroxymethyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, and hydroxypropyl methyl cellulose. Among these, cellulose ethers are preferred, and at least one selected from the group consisting of methyl cellulose and hydroxypropyl methyl cellulose is more preferred, with methyl cellulose being even more preferred, in order to suppress the scattering of particulate fuel during combustion. In other words, it is preferable that the thickener contains methyl cellulose.

[0034] The viscosity of a 2% by mass aqueous solution of the thickener at 20°C is preferably 100 mPa·s or more and 100,000 mPa·s or less, more preferably 150 mPa·s or more and 50,000 mPa·s or less, and even more preferably 200 mPa·s or more and 10,000 mPa·s or less. In this specification, the viscosity of a 2% by mass aqueous solution of a thickener at 20°C is measured using a Brookfield rotational viscometer in accordance with JIS Z8803 (2011).

[0035] The content of the thickener is preferably 0.01 mass% or more, more preferably 0.05 mass% or more, even more preferably 0.1 mass% or more, and preferably 1.0 mass% or less, more preferably 0.8 mass% or less, even more preferably 0.5 mass% or less, based on 100 mass% of the solid fuel.

[0036] In addition to the above components, the solid fuel may contain additives commonly used in solid fuels. Examples of additives include flavorings, coloring powders, stabilizers, etc. These additives may be used alone or in combination of two or more.

[0037] In the solid fuel, the monohydric alcohol (A) is methanol, the polyhydric alcohol and / or water (B) is ethylene glycol and / or diethylene glycol, and water; the fatty acid salt (C) is a stearate, It is preferable that the composition further contains methylcellulose. In the solid fuel, the monohydric alcohol (A) is methanol, the polyhydric alcohol and / or water (B) is ethylene glycol and water, the fatty acid salt (C) is a stearate, It is more preferable that the composition further contains methylcellulose. This makes the effects of the present invention more pronounced, and the composition is particularly excellent in terms of solidification, flame intensity, odor during combustion, and shape during combustion.

[0038] 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. The solid fuel is a solid material containing alcohol as a main component. To convert liquid alcohol into a solid, a fatty acid and an alkali are typically blended into the solid fuel composition, and the fatty acid is neutralized with the alkali to form a fatty acid salt, thereby achieving sufficient solidification properties, allowing the solid fuel composition to be converted into a solid solid fuel. The solid fuel in a lump form may be formed into a predetermined shape (e.g., a cylindrical shape) by cutting or the like.

[0039] The surface of the solid fuel is preferably covered with paraffin. That is, the solid fuel is preferably 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 storage stability 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 during combustion tends to be better.

[0040] 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.

[0041] The melting point of paraffin is preferably 40°C or higher, more preferably 45°C or higher, and even more preferably 50°C or higher, and is preferably 80°C or lower, more preferably 78°C or lower, and even more preferably 75°C or lower. In this specification, the melting point of paraffin is measured using a paraffin wax melting point tester in accordance with JIS K2235 (2009).

[0042] The proportion of the surface area of ​​the solid fuel that is covered with paraffin is preferably 80% or more, more preferably 90% or more, even more preferably 95% or more, particularly preferably 98% or more, and most preferably 100%.

[0043] The thickness of the paraffin is preferably 0.1 mm or more, more preferably 0.2 mm or more, and even more preferably 0.3 mm or more, and is preferably 2.0 mm or less, more preferably 1.5 mm or less, and even more preferably 1.3 mm or less. In this specification, the thickness of the paraffin is the average value of measurements taken at five points on the cut surface using a vernier caliper.

[0044] 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.

[0045] 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 ability and stability of flame force.

[0046] 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, thereby using it as fuel.

[0047] The solid fuel can be used for keeping cooked food warm, heating it, cooking it, etc. Among these, it is preferably used for keeping cooked food warm and heating it because of its moderate flame intensity and burning time.

[0048] 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 70 g, more preferably 3 to 60 g, and even more preferably 5 to 50 g.

[0049] When burning the solid fuel, the solid fuel is placed inside the tray and ignited. This type of solid fuel is suitable for keeping hot food warm after cooking has been completed. [Example]

[0050] The present invention will be specifically described based on examples, but the present invention is not limited to these examples.

[0051] The various chemicals used in the examples and comparative examples are collectively described below. Chemicals not described below were purchased from reagent manufacturers. Methylcellulose: Metrose SM400 manufactured by Shin-Etsu Chemical Co., Ltd. (viscosity of a 2% by weight aqueous solution at 20°C: 400 mPa s) Hexaglycerin stearate triester: SY Glyster TS-5S manufactured by Sakamoto Pharmaceutical Industries Fragrance: D-Limonene manufactured by Fujifilm Wako Pure Chemical Industries Color powder: Clariant Savinyl Blue GLS Paraffin: Paraffin manufactured by Yoneyama Pharmaceutical Industry (melting point: 68-70°C)

[0052] Examples and Comparative Examples <Production of solid fuel> According to the formulation shown in Table 1, each chemical was mixed for 10 minutes at 55 to 65°C using a hot stirrer to obtain a solid fuel composition. Here, fatty acids and sodium hydroxide were blended so that the fatty acid salt had the composition shown in Table 1. In addition, the total amount in each blend 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. In Examples 8, 9, 10, 18, and 25, the solid fuel was immersed in paraffin that had been heated and melted at 80° C., so that 90% of the surface of the solid fuel was covered with paraffin (thickness of paraffin: 0.5 mm). The solid fuel obtained was subjected to the following evaluations, and the results are shown in Table 1.

[0053] (Storability) The solid fuel was left to dry for 24 hours in an environment at 25°C and 50% RH. The weight was measured before and after the test, and the weight loss rate was calculated. Evaluation was made according to the following criteria. ◎: Weight loss rate is less than 40% ○: Weight loss rate is 40% or more but less than 70% ×: Weight loss rate is 70% or more

[0054] (Solidification) Solid fuel 0.1N / mm 2 The test piece was compressed with a pressure of 1000 kJ / cm2 and observed for changes in shape and seepage of liquid. Evaluation was made according to the following criteria. ◎: The shape remains the same and no liquid seeps out. 〇: The shape remains the same and a small amount of liquid seeps out ×: The shape is distorted, liquid seeps out significantly, or the product does not solidify

[0055] (Ignitability) The flame of an ignition lighter was applied to the top surface of the solid fuel, and the time until ignition was measured. Evaluation was made according to the following criteria. 〇: Ignition time is less than 2 seconds △: Ignition time is between 2 seconds and 10 seconds ×: Does not ignite

[0056] (fire force) The solid fuel was placed on the stove and ignited, and an aluminum pot containing 300 mL of water was placed on the stove. The flame intensity during the burning of the solid fuel and the boiling state of the water were visually observed. Evaluation was based on the following criteria. ◎: The flame does not overflow from the stove and boils quickly. 〇: The fire does not overflow from the stove and boils ×: The flame overflows from the stove or does not boil.

[0057] (Odor when burning) The solid fuel was placed on the stove and ignited, and an aluminum pot containing 300 mL of water was placed on the stove. The odor was smelled from a distance of 50 cm from the stove. Evaluation was based on the following criteria. ◎: No smell 〇: There is a peculiar smell, but it is not unpleasant. ×: Unpleasant odor

[0058] (Shape when burned) The solid fuel was placed on the stove and ignited, and an aluminum pot containing 300 mL of water was placed on the stove. The state of the solid fuel during burning was visually observed. Evaluation was based on the following criteria. ◎: Almost no liquefaction during combustion 〇: Less than 30% liquefaction during combustion △: Liquefaction during combustion is 30% or more but less than 50% ×: The entire amount liquefies during combustion

[0059] [Table 1]

[0060] From Table 1, it can be seen that the solid fuels of the examples, which contain at least one monohydric alcohol (A) selected from the group consisting of methanol, ethanol, and propanol, at least one polyhydric alcohol and / or water (B) selected from the group consisting of ethylene glycol, diethylene glycol, propylene glycol, and glycerin, and a fatty acid salt (C) having 12 to 22 carbon atoms, and in which the content of the monohydric alcohol (A) is 50 to 90 mass % and the content of the fatty acid salt (C) is 3 to 20 mass %, have excellent storage stability and can be suitably used as solid fuels.

Claims

1. at least one monohydric alcohol (A) selected from the group consisting of methanol, ethanol, and propanol; At least one polyhydric alcohol (B) selected from the group consisting of ethylene glycol, diethylene glycol, propylene glycol, and glycerin; and a fatty acid salt (C) having 12 to 22 carbon atoms, A solid fuel, in which the content of the monohydric alcohol (A) is 65 to 90 mass%, the content of the polyhydric alcohol (B) is 2 to 20 mass%, and the content of the fatty acid salt (C) is 5 to 16 mass%, based on 100 mass% of the solid fuel.

2. A solid fuel as described in claim 1, which contains water and has a water content of 1 to 40 mass%.

3. The solid fuel according to claim 1 or 2, which contains a thickener.

4. The solid fuel according to claim 3 , wherein the thickener comprises a polysaccharide.

5. 5. The solid fuel according to claim 1, wherein the surface is covered with paraffin.

6. 6. The solid fuel according to claim 5, wherein the thickness of the paraffin is 0.1 to 2.0 mm.

7. 7. The solid fuel according to claim 1, wherein the fatty acid salt (C) is a fatty acid salt having 16 to 20 carbon atoms.

8. the monohydric alcohol (A) is methanol, the polyhydric alcohol (B) is ethylene glycol and / or diethylene glycol, the fatty acid salt (C) is a stearate, The solid fuel according to claim 1 , further comprising water and methylcellulose.

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