JP7720580B2 - Fire-extinguishing film and its manufacturing method, fire-extinguishing composition, fire-extinguishing sheet, and fire-extinguishing molded product - Google Patents

Description

The present invention relates to a fire-extinguishing film and its manufacturing method, a fire-extinguishing composition, a fire-extinguishing sheet, and a fire-extinguishing molded product.

In recent years, technological advances have made our lives more comfortable, but at the same time, large amounts of energy are required to create that comfort. High levels of safety are required when handling energy in each of the following situations: when large amounts of energy are densely packed and stored, transported, and used.

Taking automobiles as an example, there is a risk of fire when mining fossil fuels, refining gasoline from fossil fuels, transporting gasoline, and burning gasoline in the engine. Taking electronics as an example, there is a similar risk of fire when electrical energy is transferred through power lines, when electrical energy is regulated in substations and transformers, when electrical energy is used in electrical equipment in homes and factories, or when it is temporarily stored in batteries.

To address the problem of ignition and fire, Patent Document 1 proposes the use of fire extinguishing liquid and a fire extinguisher. Patent Document 2 proposes an automatic fire extinguishing device dropped from a helicopter. Patent Document 3 proposes an aerosol fire extinguishing device.

Japanese Patent Application Publication No. 9-276440 Japanese Patent Application Laid-Open No. 2015-6302 JP 2017-080023 A

All of the prior art proposes methods for dealing with fires after a certain amount of time has passed. However, from the perspective of minimizing damage caused by fires, it is desirable to carry out some kind of fire-fighting operation (initial fire extinguishing) shortly after the fire has started.

One possible solution is to place the components of a fire extinguishing agent disclosed in prior art near an object at risk of ignition. This would allow the fire to be extinguished by the components of the fire extinguishing agent before a human can sense the fire starting in the object. However, it is necessary to address the problem of fire extinguishing agents placed in open spaces deteriorating over time. In addition, it is obviously not realistic to simply spray the fire extinguishing agent near the object; it is necessary to place the agent near the object in a form that is reasonably easy to handle.

The present invention was made in consideration of the above circumstances and provides a fire-extinguishing film that can be easily installed in areas where there is a risk of fire and that is highly effective in extinguishing a fire in its early stages, as well as a method for efficiently producing the same. The present invention also provides a fire-extinguishing composition, a fire-extinguishing sheet, and a fire-extinguishing molded product that have excellent fire-extinguishing performance.

A method for producing a fire-extinguishing film according to one aspect of the present invention includes (A) a step of kneading a thermoplastic resin with a slurry or powder containing a fire-extinguishing agent component that generates an aerosol upon combustion to obtain a kneaded mixture of a fire-extinguishing composition, and (B) a step of molding the kneaded mixture.

By forming a layer made of the kneaded material by extrusion molding in step (B), a fire-extinguishing film with excellent fire-extinguishing performance can be efficiently produced. According to the inventors' studies, by preparing a kneaded material in step (A) in which the components are sufficiently uniformly mixed, a fire-extinguishing film that stably exhibits excellent fire-extinguishing performance can be produced. Specifically, it is preferable to form a 100 μm-thick layer made of the fire-extinguishing composition, and to knead the slurry and thermoplastic resin in step (A) so that the standard deviation of the 15 haze measurements obtained from 15 locations within an area of 150 mm length x 150 mm width is 2.0 or less.

A fire-extinguishing composition according to one aspect of the present invention comprises a fire-extinguishing agent component that generates an aerosol upon combustion and a thermoplastic resin, and forms a 100 μm-thick layer of the fire-extinguishing composition. The haze is measured at 15 locations within an area of 150 mm length x 150 mm width, and the standard deviation of the 15 measurements is 2.0 or less. A standard deviation of 2.0 or less for the haze measurements at 15 locations means that the components contained in the fire-extinguishing composition are sufficiently uniformly mixed.

The extinguishing agent component in the fire-extinguishing composition contains, for example, at least an inorganic oxidizing agent that burns with the thermoplastic resin to generate thermal energy, and a radical generator, and the decomposition starting temperature of the radical generator is in the range of 90°C to 260°C. Such a fire-extinguishing agent component has excellent fire-extinguishing performance. The fire-extinguishing agent component contains, for example, at least one of a potassium salt and a sodium salt as the radical generator.

One aspect of the present invention provides various articles comprising at least one layer made from the fire-extinguishing composition. Examples of such articles include fire-extinguishing films and fire-extinguishing sheets. Further specific examples of fire-extinguishing films include shrink films (films obtained by biaxially or uniaxially stretching a fire-extinguishing sheet or fire-extinguishing film) and stretch films (films obtained by processing a fire-extinguishing film into a thin film). From the perspective of ease of installation in locations where there is a risk of fire, fire-extinguishing films and fire-extinguishing sheets may further comprise a pressure-sensitive adhesive layer or adhesive layer on at least one surface of the layer made from the fire-extinguishing composition. One aspect of the present invention provides a fire-extinguishing molded product made from the fire-extinguishing composition.

The present invention provides a fire-extinguishing film that can be easily installed in areas where there is a risk of fire and that is highly effective in extinguishing a fire in its early stages, as well as a method for efficiently producing the same. The present invention also provides a fire-extinguishing composition, a fire-extinguishing sheet, and a fire-extinguishing molded product that have excellent fire-extinguishing performance.

FIG. 1 is a cross-sectional view schematically showing one embodiment of the fire extinguishing film according to the present invention. FIG. 2 is a cross-sectional view schematically showing the fire extinguishing film shown in FIG. 1 in use. FIG. 3 is a cross-sectional view schematically showing another embodiment of the fire extinguishing film according to the present invention. FIG. 4 is a cross-sectional view schematically showing the fire extinguishing film shown in FIG. 3 in use. 5(a) and 5(b) are cross-sectional views schematically showing other embodiments of the fire extinguishing film according to the present invention. FIG. 6 is a cross-sectional view schematically showing another embodiment of the fire extinguishing film according to the present invention. FIG. 7 is a plan view schematically showing one embodiment of the fire-extinguishing molded product according to the present invention. FIG. 8 is a plan view schematically showing an example of a location where haze is measured on a sample of a fire extinguishing film (150 mm long x 150 mm wide).

Embodiments of the present invention are described in detail below. However, the present invention is not limited to the following embodiments. In the following embodiments, a fire-extinguishing film (wherein the thickness of the fire-extinguishing agent-containing layer is, for example, 1 mm or less) is exemplified as an article having at least one fire-extinguishing agent-containing layer (a layer made of a fire-extinguishing composition).

<Fire extinguishing film>
1 is a schematic cross-sectional view of a fire-extinguishing film according to this embodiment. The fire-extinguishing film 10 is a single-layer film consisting of a fire-extinguishing agent-containing layer 1. The fire-extinguishing film 10 is a film produced by cast molding, inflation molding, calendar molding, or the like.

Figure 2 is a schematic cross-sectional view showing how the fire-extinguishing film 10 is used. As shown in Figure 2, the fire-extinguishing film 10 is used in a position facing an object X that may ignite. If a fire breaks out at object X, the pre-installed fire-extinguishing film 10 will initially extinguish the fire. The object X is not particularly limited as long as it is flammable and has a surface (flat or curved) on which the fire-extinguishing film 10 can be placed. Examples of objects include electrical wires, distribution boards, control panels, storage batteries (lithium-ion batteries, etc.), recycling boxes, trash cans, automotive-related components, and electrical outlets. The fire-extinguishing film 10 can also be used as a shrink film or stretch film by selecting a thermoplastic resin and processing it (e.g., by stretching or thinning).

The fire extinguishing agent-containing layer 1 is a layer containing a fire extinguishing agent component and a thermoplastic resin. The fire extinguishing agent component generates an aerosol upon combustion. The fire extinguishing agent component contains, for example, at least an inorganic oxidizing agent and a radical generator. The radical generator has the effect of stabilizing combustion radicals and suppressing the combustion chain reaction (negative catalytic action).

The thickness of the extinguishing agent-containing layer 1 can be set appropriately depending on the fire to be extinguished, the installation location, and the amount of extinguishing agent components to be blended. The thickness of the extinguishing agent-containing layer 1 may be, for example, 1 mm or less, and may be 20 to 800 μm, or 50 to 400 μm.

The content of the extinguishing agent component in the extinguishing agent-containing layer 1 (based on the mass of the extinguishing agent-containing layer 1) is, for example, 30 to 80 mass%, preferably 40 to 75 mass%, and more preferably 50 to 70 mass%. A content of the extinguishing agent component of 30 mass% or more can achieve excellent fire extinguishing performance, while a content of 80 mass% or less can achieve film formability. The amount of the extinguishing agent component per unit area can be set depending on the target to be extinguished. For example, for a small fire such as a cigarette, 15 g/m2 or ^more is sufficient. For a fire with 1 g of solid fuel, 30 g/ ^m2 or more is sufficient. For a large fire or a large fire such as a fire from a lithium-ion battery, 250 g/ ^m2 or more is preferable.

[Fire extinguishing agent components]
As described above, the extinguishing agent-containing layer 1 contains an inorganic oxidizing agent and a radical generator as extinguishing agent components. These components will be described below.

The inorganic oxidizing agent (hereinafter sometimes referred to as "component (A)") is a component that burns together with the thermoplastic resin to generate thermal energy. Examples of inorganic oxidizing agents include potassium chlorate, sodium chlorate, strontium chlorate, ammonium chlorate, and magnesium chlorate. One of these may be used alone, or two or more may be used in combination.

The radical generator (hereinafter sometimes referred to as "component (B)") is a component that generates aerosols (radicals) using the thermal energy generated by the combustion of the thermoplastic resin and inorganic oxidizer. It is preferable to use a radical generator with a decomposition onset temperature between 90°C and 260°C. Examples of radical generators include potassium salts and sodium salts. Potassium salts include potassium acetate, potassium propionate, monopotassium citrate, dipotassium citrate, tripotassium citrate, monopotassium trihydrogen ethylenediaminetetraacetate, dipotassium dihydrogen ethylenediaminetetraacetate, tripotassium monohydrogen ethylenediaminetetraacetate, tetrapotassium ethylenediaminetetraacetate, potassium hydrogen phthalate, dipotassium phthalate, potassium hydrogen oxalate, dipotassium oxalate, and potassium bicarbonate. Examples of sodium salts include sodium acetate, sodium citrate, and sodium bicarbonate. These may be used alone or in combination.

The content of component (A) is, for example, 10 to 60 parts by mass, preferably 25 to 55 parts by mass, and more preferably 30 to 50 parts by mass, per 100 parts by mass of the combined total of components (A) and (B). The content of component (B) is, for example, 40 to 90 parts by mass, preferably 45 to 75 parts by mass, and more preferably 50 to 70 parts by mass, per 100 parts by mass of the combined total of components (A) and (B).

Commercially available fire extinguishing agents may be used as the fire extinguishing agent components incorporated into the fire extinguishing agent-containing layer 1. An example of a commercially available fire extinguishing agent is Aerosol Fire Extinguisher K-1 manufactured by Yamato Protec Co., Ltd.

[Thermoplastic resin]
The thermoplastic resin in the fire-extinguishing agent-containing layer 1 burns together with the inorganic oxidizer. Examples of the thermoplastic resin include polyolefin resins such as polypropylene resins, polyethylene resins, poly(1-)butene resins, and polypentene resins, polystyrene resins, acrylonitrile-butadiene-styrene resins, methyl methacrylate-butadiene-styrene resins, ethylene-vinyl acetate resins, ethylene-propylene resins, polycarbonate resins, polyphenylene ether resins, acrylic resins, polyamide resins, polyvinyl chloride resins, and fluorine-based resins.

The thermoplastic resin content of the extinguishing agent-containing layer 1 (based on the mass of the extinguishing agent-containing layer 1) is, for example, 20 to 70 mass%, preferably 25 to 60 mass%, and more preferably 30 to 50 mass%. A thermoplastic resin content of 20 mass% or more enables film formability, while a content of 70 mass% or less enables excellent fire extinguishing performance.

[Other ingredients]
Examples of other components that may be blended into the fire extinguishant-containing layer 1 include dispersants, solvents, colorants, ultraviolet absorbers, antioxidants, inorganic fillers, and adhesives. These components may be appropriately selected depending on the composition of the fire extinguishant-containing layer 1 and the type of thermoplastic resin. The content of other components in the fire extinguishant-containing layer 1 (based on the mass of the fire extinguishant-containing layer 1) is, for example, 10 mass% or less.

<Fire extinguishing film manufacturing method>
The method for manufacturing the fire extinguishing film 10 includes the following steps.
(A) a step of kneading a slurry or powder containing a fire extinguishing agent component that generates an aerosol upon combustion with a thermoplastic resin to obtain a kneaded product of a fire extinguishing composition; (B) a step of molding a layer made of the kneaded product.

By preparing a mixture in step (A) in which the components contained in the fire extinguishing agent are sufficiently uniformly mixed, a fire extinguishing film 10 that stably exhibits excellent fire extinguishing performance can be produced. Whether the components contained in the fire extinguishing agent are sufficiently uniformly mixed can be evaluated by forming a 100 μm-thick layer of the fire extinguishing composition, measuring the haze at 15 locations within an area of 150 mm length x 150 mm width, and calculating the standard deviation of the 15 measurements. According to the inventors' studies, a fire extinguishing agent-containing layer 1 that stably exhibits excellent fire extinguishing performance can be produced by ensuring that the standard deviation of the 15 haze measurements is 2.0 or less. In other words, it is preferable to thoroughly knead the slurry and thermoplastic resin in step (A) so that the standard deviation of the 15 haze measurements is 2.0 or less. Examples of dispersion media used to prepare the slurry include ethyl acetate, butyl acetate, ethyl methyl ketone, methyl isobutyl ketone, methanol, ethanol, and isopropanol.

Steps (A) and (B) may be carried out using an extruder. That is, it is preferable to prepare the mixture using an extruder (more preferably a twin-screw extruder) having a kneading section for kneading the fire-extinguishing composition. The fire-extinguishing film 10 according to this embodiment is a single-layer film consisting of the fire-extinguishing agent-containing layer 1, and can be cast-molded, for example, by T-die extrusion.

The manufacturing method according to this embodiment allows for efficient production of the fire extinguishing film 10 by extrusion molding. The fire extinguishing film 10 can be easily installed in areas where there is a risk of fire and is highly effective in extinguishing a fire in its early stages. This makes it useful in preventing the spread of fire.

Although the embodiments of the present invention have been described in detail above, the present invention is not limited to the above embodiments. For example, in the above embodiments, a single-layer film (extruded film) consisting of a fire-extinguishing agent-containing layer 1 was exemplified as the fire-extinguishing film, but the fire-extinguishing film may also be a multilayer film including a fire-extinguishing agent-containing layer 1. The fire-extinguishing film 20 shown in Figure 3 comprises a fire-extinguishing agent-containing layer 1 and a substrate 3, in this order. The fire-extinguishing agent-containing layer 1 may be provided on at least a portion of one surface 3a of the substrate 3, but may also be provided on the entire surface 3a, as shown in Figure 3.

A transparent resin substrate can be selected for the substrate 3. Examples of resin substrate materials include polyolefins (LLDPE, PP, COP, CPP, etc.), polyesters (PET, etc.), fluororesins (PTFE, ETFE, EFEP, PFA, FEP, PCTFE, etc.), PVC, PVA, acrylic resins, epoxy resins, polyamides, and polyimides. Among these, the resin substrate may contain at least one selected from the group consisting of HDPE, LDPE, OPP, PVC, PVDC, PET, PBT, PAN, PCTFE, and COP, which have low water vapor permeability and facilitate suppression of deterioration of the fire extinguishing agent components. Furthermore, selecting a highly transparent material facilitates visual inspection of the fire extinguishing film 20 and confirmation of its replacement timing. The substrate 3 may be made of metals such as aluminum and stainless steel, or may be non-combustible paper or glass cloth. The substrate 3 may also contain a fire extinguishing agent.

The thickness and breaking strength of the substrate 3 can be selected appropriately depending on the amount of heat generated during a fire, the impact, the allowable space, and other factors. For example, a thick resin substrate makes it easier to suppress water vapor transmission, provides strength and rigidity, and allows for a highly flat form, making it easier to handle. Furthermore, a thin substrate allows the fire-extinguishing film to be installed in a narrow space. The thickness of the substrate 3 can be, for example, 10 to 150 μm, and may be 20 to 50 μm. The substrate 3 may also be a laminate of multiple resin films.

The substrate 3 may be a resin substrate (high-strength, heat-resistant resin substrate) that is heat-resistant and impact-resistant. A high-strength, heat-resistant substrate preferably has at least one of a tensile strength of 20 N/cm or more and a melting point of 500°C or more. The resin substrate may contain reinforcing materials such as carbon, glass, stainless steel, aluminum, and ceramic, particularly woven fabrics (cloths) made of fibers made from these materials. The heat- and impact-resistant properties of the resin substrate can prevent holes from being created in the resin substrate due to heat or impact during ignition. This prevents the fire extinguishing agent from being sprayed in the opposite direction from the target X (see Figure 4).

The substrate 3 preferably has water vapor barrier properties to the extent that the properties of the fire extinguishing agent component contained in the fire extinguishing agent-containing layer 1 do not change significantly, regardless of the installation location or usage environment of the fire extinguishing film 20. The water vapor permeability of the substrate 3 (under conditions of 40°C/90% RH in accordance with JIS K 7129) is not particularly limited as it can be designed depending on the type of fire extinguishing agent component, but can be 2 x ¹⁰² g/ ^m2 /day or less, and may be 1 x ¹⁰² g/ ^m2 /day or less. From the viewpoint of adjusting the water vapor permeability, the substrate 3 may be provided with a vapor-deposited layer (alumina vapor-deposited layer or silica vapor-deposited layer) having water vapor barrier properties.

The fire-extinguishing film may further comprise a pressure-sensitive adhesive layer or an adhesive layer. Fire-extinguishing film 30A shown in FIG. 5(a) is composed of a fire-extinguishing agent-containing layer 1, a pressure-sensitive adhesive layer 4 provided on one side of the fire-extinguishing agent-containing layer 1, and a release film 5 provided to cover the pressure-sensitive adhesive layer 4. Fire-extinguishing film 30B shown in FIG. 5(b) is composed of a substrate 3, a fire-extinguishing agent-containing layer 1, a pressure-sensitive adhesive layer 4 provided on one side of the fire-extinguishing agent-containing layer 1, and a release film 5 provided to cover the pressure-sensitive adhesive layer 4. Release film 5 is peeled off when using fire-extinguishing films 30A and 30B, and may be made of resin or paper. Having a pressure-sensitive adhesive layer 4 or an adhesive layer in the fire-extinguishing film makes it even easier to install the fire-extinguishing film in areas where there is a risk of fire.

The fire-extinguishing film may have a configuration in which the fire-extinguishing agent-containing layer 1 is sandwiched between other layers. The fire-extinguishing film 40 shown in Figure 6 comprises the fire-extinguishing agent-containing layer 1 and surface layers 6a and 6b arranged to sandwich the fire-extinguishing agent-containing layer 1. For example, the surface layers 6a and 6b can be made of the same resin substrate as the substrate 3. By providing the surface layers 6a and 6b, the durability and design of the fire-extinguishing agent-containing layer 1 can be improved, and a fire-extinguishing film 40 with high strength can be obtained.

In the above embodiment, a fire-extinguishing film having a fire-extinguishing agent-containing layer 1 with a thickness of 1 mm or less was exemplified, but a fire-extinguishing sheet (not shown) having a fire-extinguishing agent-containing layer with a thickness of more than 1 mm may also be produced. The thickness of the fire-extinguishing agent-containing layer may be set appropriately depending on the intended use of the fire-extinguishing sheet, and may be, for example, 1 to 5 mm or 1 to 3 mm.

In the above embodiment, the extinguishing agent-containing layer 1 is made of a fire-extinguishing composition in which the components are sufficiently uniformly mixed. However, this fire-extinguishing composition may be used for various purposes. For example, a molded product may be made using the fire-extinguishing composition. Figure 7 is a schematic plan view of an outlet cover made of the fire-extinguishing composition, which is an example of a molded product. The outlet cover 50 shown in Figure 7 has a substantially rectangular shape in plan view and is provided with multiple openings 50a corresponding to the shape of the plug. By making the outlet cover 50 out of the fire-extinguishing composition, it is possible to prevent the spread of fire even if the plug breaks out. The fire-extinguishing composition can be made by injection molding, blow molding, vacuum molding, or the like.

The present invention will be described in more detail by the following examples, but the present invention is not limited to these examples.

Example 1
The following materials were prepared:
Fire extinguishing agent component: Slurry of potassium chlorate (inorganic oxidizer) and tripotassium citrate (potassium salt) dispersed in ethyl acetate solvent (product name: K-1, manufactured by Yamato Protec Co., Ltd.)
Thermoplastic resin: polyethylene pellets (product name: LC600A, manufactured by Japan Polyethylene Co., Ltd.)

The above slurry was added to polyethylene pellets and dry-blended. The amount of slurry added was adjusted so that the amount of fire-extinguishing agent components contained in the slurry was 50 parts by mass per 100 parts by mass of polyethylene pellets. After the slurry had soaked into the polyethylene pellets and the pellets had become smooth, a fire-extinguishing film with a 100 μm-thick fire-extinguishing agent-containing layer was produced by T-die extrusion molding using a twin-screw extruder with a kneading zone.

Example 2
A fire-extinguishing film was prepared in the same manner as in Example 1, except that the thickness of the fire-extinguishing agent-containing layer was changed to 50 μm instead of 100 μm.

Example 3
A fire-extinguishing film was prepared in the same manner as in Example 1, except that the amount of the fire-extinguishing agent component per 100 parts by mass of polyethylene pellets was adjusted to 30 parts by mass instead of 50 parts by mass.

Example 4
A fire-extinguishing film was prepared in the same manner as in Example 2, except that the amount of the fire-extinguishing agent component per 100 parts by mass of polyethylene pellets was adjusted to 30 parts by mass instead of 50 parts by mass.

<Comparative Example 1>
A fire-extinguishing film was produced in the same manner as in Example 1, except that a single-screw extruder without a kneading zone was used instead of the twin-screw extruder with a kneading zone.

<Comparative Example 2>
A fire-extinguishing film was prepared in the same manner as in Example 1, except that no slurry containing a fire-extinguishing agent component was used.

<Comparative Example 3>
A fire-extinguishing film was prepared in the same manner as in Example 2, except that no slurry containing a fire-extinguishing agent component was used.

<Haze measurement>
The haze of the fire-extinguishing films according to Examples 1 to 4 and Comparative Example 1 was measured as follows. Specifically, the prepared fire-extinguishing films were cut into 150 mm length x 150 mm width samples. Using a haze meter (NDH2000) manufactured by Nippon Denshoku Industries Co., Ltd., the haze (unit: %) was measured at 15 points (positions spaced apart at approximately equal intervals, see Figure 8) on the surface of the sample. The standard deviation (unit: %) of the 15 measured values was calculated. The results are shown in Table 1.

<Fire extinguishing test>
The fire-extinguishing films according to the examples and comparative examples were cut to 20 mm x 20 mm to obtain samples. A 1 ^cm3 solid ignition material (product name: Hi-Chucker L CK-30, made with compressed wood fiber, manufactured by Onoue Seisakusho Co., Ltd.) was measured. The ignition material was placed in a pan placed inside an aluminum container, and then ignited to generate a flame. The sample was held with tweezers and brought close to the burning ignition material to a height of 20 mm. After the sample was burned, it was observed whether the flame could be extinguished within 5 seconds. Fire extinguishing performance was evaluated based on the following criteria. The results are shown in Table 1.
A: The fire was extinguished within 5 seconds.
B: There were some areas where the fire could not be extinguished within 5 seconds.
C: The fire could not be extinguished and burned violently.

The present invention provides a fire-extinguishing film that can be easily installed in areas where there is a risk of fire and that is highly effective in extinguishing a fire in its early stages, as well as a method for efficiently producing the same. The present invention also provides a fire-extinguishing composition, a fire-extinguishing sheet, and a fire-extinguishing molded product that have excellent fire-extinguishing performance.

1...fire extinguishing agent-containing layer, 3...substrate, 3a...surface, 4...adhesive layer, 5...release film, 6a, 6b...surface layer, 10, 20, 30A, 30B, 40...fire extinguishing film, 50...outlet cover (fire extinguishing molded product), 50a...opening, X...target

Claims (1)

(A) obtaining a fire-extinguishing composition by kneading a slurry or powder containing a fire-extinguishing agent component that generates an aerosol upon combustion with a thermoplastic resin in a kneading zone of a twin-screw extruder having the kneading zone;
(B) molding the fire-extinguishing composition by T-die extrusion molding using the twin-screw extruder to obtain a fire-extinguishing film having a thickness of 20 to 800 μm;
Including,
the content of the thermoplastic resin in the fire extinguishing composition is 20 to 70 mass% based on the mass of the fire extinguishing composition;
The fire extinguishing composition has a standard deviation of 15 haze measurements of 2.0 or less,
The 15 measurement values obtained by the haze measurement are measurement values obtained by measuring the haze at 15 points within an area of 150 mm length x 150 mm width on the haze measurement film ,
the film for haze measurement is a 100 μm thick film made of the fire-extinguishing composition obtained by kneading in step (A), and is obtained by T-die extrusion molding using the twin-screw extruder .