Persulfate particle composition having particle surface coated with non-combustible material and production method of the same

Abstract

To provide a non-combustible persulfate particle composition having particle surfaces coated with a non-combustible material, and a production method of the same.SOLUTION: A persulfate powder composition according to the present invention is a persulfate particle composition having particle surfaces coated with a non-combustible material, characterized in that the non-combustible material is contained in an amount of 1.55 wt.% to 2.00 wt.% based on a weight of the persulfate particle composition. This makes it possible to provide a non-combustible persulfate particle composition that does not correspond to Class 1 dangerous goods (oxidizing solid) under the Japanese Fire Service Act.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention provides a persulfate particle composition in which the particle surface is coated with a non-combustible material, and a method for producing the same.

Background Art

[0002] Persulfates represented by ammonium persulfate are oxidizing solids that are widely used industrially mainly as polymerization initiators for emulsion polymerization, oxidative bleaching agents, copper etching agents, etc. Such oxidizing solids are regulated in handling by the Fire Service Act of Japan, and when determined as Class 1 Dangerous Goods (oxidizing solids) under the Fire Service Act, they are subject to strict legal restrictions in manufacturing, transportation, storage, etc. Especially when handling in a factory, it is necessary to install fire prevention or explosion-proof equipment and secure open spaces, etc., which is disadvantageous in terms of cost.

[0003] In the determination of Class 1 dangerous goods (oxidizing solids) under the Japanese Fire Service Act mentioned above, a combustion test and a falling ball impact sensitivity test are conducted. In the combustion test, a mixture of the test article and wood powder is burned, and the combustion time is compared with the combustion time when a mixture of a reference substance (potassium bromate, potassium perchlorate) and wood powder is burned, and it is classified into Rank 1 to Rank 3. Specifically, when the combustion time of the mixture of the test article and wood powder is less than or equal to the combustion time of the mixture of potassium bromate and wood powder, it is Rank 1; when it exceeds the combustion time of the mixture of potassium bromate and wood powder and is less than or equal to the combustion time of the mixture of potassium perchlorate and wood powder, it is Rank 2; when it exceeds the combustion time of the mixture of potassium perchlorate and wood powder, or when the mixture of the test article and wood powder is non-combustible, it is Rank 3. Also, in the falling ball impact sensitivity test, the probability of explosion when a steel ball is dropped onto a mixture of the test article and red phosphorus is compared with the probability of explosion when a steel ball is dropped onto a mixture of a reference substance (potassium chlorate, potassium nitrate) and red phosphorus, and it is classified into Rank 1 to Rank 3. Specifically, when the probability of explosion of the mixture of the test article and red phosphorus is 1 / 2 or more of the probability of explosion of the mixture of potassium chlorate and red phosphorus, it is Rank 1; when it is less than 1 / 2 of the probability of explosion of the mixture of potassium chlorate and red phosphorus and 1 / 2 or more of the probability of explosion of the mixture of potassium nitrate and red phosphorus, it is Rank 2; when it is less than 1 / 2 of the probability of explosion of the mixture of potassium nitrate and red phosphorus, it is Rank 3. Then, based on the results of these combustion test and falling ball impact sensitivity test, it is evaluated which of Class 1 oxidizing solid, Class 2 oxidizing solid, Class 3 oxidizing solid, and non-dangerous goods it corresponds to. If it is Rank 1 in the combustion test and Rank 3 in the falling ball impact sensitivity test, it is determined to be a Class 1 oxidizing solid; if it is Rank 3 in both the combustion test and the falling ball impact sensitivity test, it is determined to be a non-dangerous good.

[0004] For example, ammonium persulfate is classified as a Class 1 dangerous good (oxidizing solid) under the Fire Service Act in Non-Patent Document 1. On the other hand, Non-Patent Document 2 states that it is non-flammable and does not fall under Class 1 dangerous goods (oxidizing solid) of the Fire Service Act. However, for commonly available ammonium persulfate (manufactured by Fuji Film Wako Pure Chemical Corporation, Mitsubishi Gas Chemical Company, Inc., and ADEKA Corporation), the inventors and multiple analytical institutions conducted the above-mentioned combustion test and falling ball impact sensitivity test respectively. As a result, all ammonium persulfate samples were ranked 1 in the combustion test and 3 in the falling ball impact sensitivity test, and were classified as Class 1 oxidizing solids.

[0005] As such, since persulfates such as ammonium persulfate are classified as Class 1 dangerous goods (oxidizing solids) under the Fire Service Act, in order to handle them safely and at low cost on an industrial scale, it is required that they not be classified as Class 1 dangerous goods (oxidizing solids) under the Fire Service Act, that is, they be non-dangerous goods. Specifically, since the falling ball impact sensitivity test result for pure samples is at least Rank 3, if a persulfate that can be judged as non-combustible in the combustion test is manufactured, it can be judged as a non-dangerous good, which is advantageous when handling on an industrial scale.

[0006] In the combustion test, as a method for making flammable substances non-flammable, Patent Document 1 discloses a method of coating nitrates with an oxygen-blocking material such as dodecylbenzenesulfonic acid and further attaching silica. Patent Document 2 discloses a non-flammable particulate composition containing strontium nitrate and / or barium nitrate and hydrophobic silica. Patent Document 3 describes a powdery composition containing porous silica and non-porous silica in a barium compound. However, none of the documents describe the non-flammability of persulfates.

Prior Art Documents

Non-Patent Documents

[0007]

Non-Patent Document 1

Non-Patent Document 2

Patent Documents

[0008]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0009] As described above, there is no method for obtaining incombustible persulfate particles. Therefore, an object of the present invention is to provide an inexpensive and simple method for producing an incombustible persulfate particle composition in which the particle surface is coated with an incombustible material, and a method for producing the same.

Means for Solving the Problems

[0010] As a result of intensive studies, the present inventors have found that an incombustible persulfate particle composition in which the particle surface is coated with an incombustible material can be produced by mixing an incombustible material dissolved or dispersed in a solvent with persulfate particles and then removing the solvent. Furthermore, it has been found that by setting the content of the incombustible material to 1.55% by weight to 2.00% by weight based on the weight of the persulfate particle composition, an incombustible persulfate particle composition that does not fall under Class 1 Dangerous Goods (Oxidizing Solids) in the Fire Service Act of Japan can be obtained.

[0011] That is, the present invention is as follows. (1) A persulfate particle composition in which the surface of the persulfate particles is coated with a non-combustible material, wherein the non-combustible material is contained in an amount of 1.55% to 2.00% by weight based on the weight of the persulfate particle composition. (2) The persulfate particle composition according to (1), wherein the non-combustible material is at least one selected from inorganic compounds and organic compounds that are inert to persulfates. (3) The persulfate particle composition according to (1) or (2), wherein the non-combustible material is a water-soluble inorganic compound. (4) The persulfate particle composition according to any one of (1) to (3), wherein the non-combustible material is at least one selected from ammonium sulfate, sodium sulfate, potassium sulfate, ammonium chloride, potassium chloride, sodium chloride, and calcium chloride. (5) The persulfate particle composition according to any one of (1) to (4), wherein the persulfate is at least one selected from ammonium persulfate, potassium persulfate, and sodium persulfate. (6) The persulfate particle composition according to any one of (1) to (5), which does not fall under Class 1 Dangerous Goods (Oxidizing Solids) of the Fire Service Act of Japan. (7) The persulfate particle composition according to any one of (1) to (6), which does not catch fire or ignite when a heated nichrome wire is brought into contact with a mixture mixed with wood powder for 10 seconds in a combustion test, which is a test method for determining Class 1 Dangerous Goods (Oxidizing Solids) of the Fire Service Act of Japan. (8) A method for producing a persulfate particle composition, comprising mixing a non-combustible material dissolved or dispersed in a solvent and persulfate particles, and then removing the solvent. (9) The method for producing a persulfate particle composition according to (8), wherein the non-combustible material is at least one selected from inorganic compounds and organic compounds that are inert to persulfates. (10) The method for producing a persulfate particle composition according to (8) or (9), wherein the non-combustible material is at least one selected from ammonium sulfate, sodium sulfate, potassium sulfate, ammonium chloride, potassium chloride, sodium chloride, and calcium chloride. (11) The method for producing a persulfate particle composition according to any one of (8) to (10), wherein the solvent is removed by drying.

Advantages of the Invention

[0012] According to the present invention, a persulfate particle composition in which a non-combustible material is coated on the particle surface can be produced by an inexpensive and simple method. Furthermore, it is possible to produce a persulfate particle composition that is made non-combustible and does not fall under Class 1 Dangerous Goods (Oxidizing Solids) in the Fire Service Act of Japan.

Embodiments for Carrying Out the Invention

[0013] Hereinafter, the present invention will be described in more detail together with embodiments.

[0014] The persulfate particle composition according to the present invention is a persulfate particle composition in which the particle surface is coated with a non-combustible material, and is characterized in that the non-combustible material is contained in an amount of 1.55% by weight to 2.00% by weight based on the weight of the persulfate particle composition. Further, the method for producing the persulfate particle composition of the present invention is a method characterized by mixing a non-combustible material dissolved or dispersed in a solvent with persulfate particles, and then removing the solvent.

[0015] As the non-combustible material used in the present invention, there is no particular limitation as long as it is an inorganic compound or an organic compound that is inert and non-combustible to persulfate. Here, being inert to persulfate means that when in contact with persulfate, it does not react with persulfate and does not cause decomposition of persulfate or itself. A non-combustible material refers to a material that does not cause ignition or combustion upon contact with direct fire or heating above room temperature. Among them, it is preferable to use a water-soluble inorganic compound because of the simplicity of mixing the non-combustible material dissolved or dispersed in a solvent with persulfate particles and subsequent solvent removal. Also, a water-soluble inorganic compound is an inorganic compound that dissolves 10 g or more in 100 mL of water at normal temperature and pressure. Specific examples of such inorganic compounds include ammonium sulfate, potassium sulfate, sodium sulfate, ammonium chloride, potassium chloride, sodium chloride, and calcium chloride. Since persulfate is generally produced by electrolysis of ammonium sulfate, ammonium sulfate is included as an impurity in persulfate. Therefore, if the non-combustible material used is ammonium sulfate, no new impurities will increase, and it is easiest to maintain the original performance of persulfate, so it is most preferable. These non-combustible materials may be used alone or in combination of multiple types from the above substances.

[0016] Also, as the form containing the non-combustible material, there are those in which persulfate particles and the non-combustible material are dry-mixed, and those in which the surface of the persulfate particles is coated with the non-combustible material. However, in the case of those in which persulfate particles and the non-combustible material are dry-mixed, since there are more crystal faces of each exposed persulfate particle compared to those in which the surface of the persulfate particles is coated with the non-combustible material, it is easy to burn and may be determined as a dangerous substance in the determination test for Class 1 dangerous goods. Therefore, it is necessary to coat the surface of the persulfate particles with a non-combustible material to suppress the exposure of the crystal faces of each persulfate particle. Note that coating means covering the entire surface or a part of the surface of each particle of persulfate with a non-combustible material. In the present invention, it is not essential that the entire surface of each particle of persulfate is completely covered with a non-combustible material, and it is sufficient that a part of the surface of each particle of persulfate can be covered with a non-combustible material to the extent that it does not burn in the combustion test of the Fire Service Act.

[0017] Specifically, if the content of the non-combustible material in the persulfate particle composition is too low, the amount of persulfate particles with exposed crystal planes will increase, making them more likely to burn, and thus non-combustibility cannot be achieved. Conversely, if it is excessive, although non-combustibility can be achieved, the non-combustible material will inhibit the original performance of the persulfate. Therefore, the content of the non-combustible material in the persulfate is preferably 1.55% by weight or more and 5.00% by weight or less, more preferably 1.55% by weight or more and 2.00% by weight or less, and most preferably 1.65% by weight or more and 2.00% by weight or less, based on the weight of the persulfate particle composition.

[0018] The persulfate used in the present invention can be any of the commonly circulated compounds such as ammonium persulfate, potassium persulfate, and sodium persulfate. And one of the above substances can be used alone, or a plurality of them can be combined. Furthermore, these persulfates only need to be in particulate form, and various physical properties such as particle diameter are not particularly limited. However, especially when the particles are too large, there is a possibility that they cannot be uniformly mixed when mixed with the non-combustible material dissolved or dispersed in the solvent. Therefore, as the persulfate particles used in the present invention, when sieved with sieves having mesh openings of 45 μm and 2000 μm, the content of persulfate with a primary particle size of 45 μm or more and less than 2000 μm (not passing through a sieve with a mesh opening of 45 μm and passing through a sieve with a mesh opening of 2000 μm) is preferably 80% by weight or more. More preferably, it is 90% by weight or more.

[0019] The method of coating the persulfate particles with the non-combustible material is not particularly limited, but from the simplicity of the operation, a method of mixing the non-combustible material dissolved or dispersed in the solvent with the persulfate particles and then removing the solvent is preferred.

[0020] When mixing the persulfate particles and the non-combustible material by the above method, either a solution in which the non-combustible material is dissolved in the solvent or a dispersion in which it is dispersed can be used. However, since it can be uniformly mixed with the persulfate in a simple method, it is more preferable to use a solution in which the non-combustible material is dissolved in the solvent.

[0021] Here, the concentration of the non-combustible material contained in the solution or dispersion of the non-combustible material mixed with the persulfate particles is preferably high for inexpensive and efficient production, more preferably a saturated solution. Specifically, when water is used as the solvent and ammonium sulfate is used as the non-combustible material, an aqueous ammonium sulfate solution with a concentration of 30% by weight or more is preferred, more preferably an aqueous ammonium sulfate solution with a concentration of 40% by weight or more, and most preferably a saturated aqueous solution. Also, when water is used as the solvent and potassium chloride or sodium chloride is used as the non-combustible material, an aqueous potassium chloride or sodium chloride solution with a concentration of 15% by weight or more is preferred, more preferably an aqueous potassium chloride or sodium chloride solution with a concentration of 20% by weight or more, and most preferably a saturated aqueous solution.

[0022] The method of mixing the non-combustible material dissolved or dispersed in the solvent with the persulfate particles is not particularly limited as long as the components can be uniformly mixed. Specifically, methods using stirring blade types such as high-speed mixers, Henschel mixers, Nauter mixers, ribbon blenders, or rotary mixers such as V-type mixers and conical blenders, methods using grinding mixers such as jet mills, bead mills, and ball mills, and methods using kneaders such as screw feeders are available.

[0023] And the method of removing the solvent from the persulfate particle composition mixed with the non-combustible material dissolved in the solvent is not particularly limited as long as the solvent can be sufficiently removed. Specifically, methods such as filtration, centrifugation, drying by heating at normal pressure, and vacuum drying can be mentioned, but a drying method that can simply and efficiently remove the solvent is preferred. In order to suppress the alteration and decomposition of the persulfate by heating, a method by vacuum drying is more preferred. Specifically, there are methods using shelf dryers, rotary vacuum dryers such as conical dryers, fluidized bed dryers, vibration dryers, etc.

Examples

[0024] Hereinafter, the invention will be described in more detail based on examples, but the present invention is not limited by these examples.

[0025] [Contents of ammonium sulfate, potassium chloride, and sodium chloride contained in the persulfate particle composition] The weight of ammonium sulfate contained in the persulfate particle composition coated with ammonium sulfate was quantified by ion chromatography, and the amount of ammonium sulfate in the persulfate particle composition (weight % concentration of ammonium sulfate relative to the weight of the persulfate particles) was calculated using the following formula. (Content of ammonium sulfate contained in the persulfate particle composition) =(Weight of ammonium sulfate contained in the persulfate particle composition / (Weight of the persulfate particle composition) × 100

[0026] When potassium chloride or sodium chloride was used as a non-combustible material, the amount of potassium chloride or sodium chloride content in the persulfate particle composition was calculated in the same manner as in the case of the above-mentioned ammonium sulfate.

[0027] [Combustion test] In accordance with the method specified by the Fire Service Act, a combustion test was carried out in the following procedure.

[0028] A test article weighing 24 g that had passed through a wire mesh with an opening of 1.18 mm was mixed with 6 g of wood powder (particle size 250 - 500 mm) that had been dried at 105°C for 4 hours or more (weight ratio of test article to wood chips = 4:1). Subsequently, the above mixed sample was placed in a conical cup (height of cone: diameter of bottom = 1:1.75), and then this was turned over onto a heat insulating plate with a thickness of 10 mm or more to create a conical deposit. After leaving the conical deposit at the test location for 1 hour, an annular nichrome wire heated to approximately 1000°C by energization was brought into contact with the base of the conical deposit for a maximum of 10 seconds until it was clearly determined whether it completely ignited and flamed or did not ignite at all, and the combustion time was measured. At that time, if it did not ignite or flame within 10 seconds, if it extinguished after ignition and shifted to a state of charring or smoking with the carbonization of the wood powder progressing, and if the wood chips remained unburned inside the conical deposit or above the ignition position even after ignition and extinguishing, it was considered non-combustible, and if the conical deposit completely burned after ignition, it was considered combustible. The above test was conducted 5 times. If it became non-combustible even once in the 5 tests, an additional 5 tests (total of 10 tests) were conducted. And if a non-combustible result was obtained 6 times out of 10, it was determined to be non-combustible, if the combustion time was measured 5 times or more out of 10, it was determined to be combustible, and the average value was taken as the combustion time. The test was terminated when a non-combustible result was obtained 6 times or when a combustible result was obtained 5 times.

[0029] In addition, in the Fire Service Act, a mixed sample with a weight ratio of test article to wood chips = 1:1 is also prepared simultaneously, and a combustion test is conducted. Among the combustion times of the mixed samples with weight ratios of 4:1 and 1:1, the shorter combustion time is taken as the combustion time of the test article. However, for ammonium persulfate, since the combustion time of the mixed sample with a weight ratio of 4:1 is shorter, the combustion test with the test article having a weight ratio of 1:1 is not carried out in the present invention.

[0030] Example 1 In a 1000 mL Erlenmeyer flask with the bottom cut off and inverted, 400 g of ammonium persulfate (manufactured by FUJIFILM Wako Pure Chemical Industries, Ltd., purity 98.0% or higher, particle content not passing through a sieve with an opening of 45 μm and passing through a sieve with an opening of 2000 μm 99.0% by weight or more) and 11.3 g of a saturated ammonium sulfate aqueous solution as a non-combustible material solution were added. Then, stirring and mixing were carried out for 1 hour using a screw blade (left-handed, blade outer diameter 40 mm, blade inner diameter 18 mm, blade pitch 40 mm, blade thickness 5 mm). Subsequently, the wet cake of the ammonium persulfate particle composition obtained by the above operation was vacuum dried using a shelf dryer under the conditions of 40 °C and 10 Torr to obtain an ammonium persulfate particle composition with the particle surface coated with ammonium sulfate. As a result of calculating the ammonium sulfate content of the ammonium persulfate particle composition, it was 1.73% by weight. Also, as a result of conducting a combustion test, all 6 measurements were non-combustible during the 6 measurements.

[0031] Example 2 In a 1000 mL eggplant flask, 400 g of ammonium persulfate (manufactured by FUJIFILM Wako Pure Chemical Industries, Ltd., particle content not passing through a sieve with an opening of 45 μm and passing through a sieve with an opening of 2000 μm 99.0% by weight or more) and 11.3 g of a saturated ammonium sulfate aqueous solution as a non-combustible material solution were added. Then, it was rotated using an evaporator and mixed for 1 hour. Subsequently, the wet cake of the ammonium persulfate particle composition obtained by the above operation was vacuum dried using a shelf dryer under the conditions of 40 °C and 10 Torr to obtain an ammonium persulfate particle composition with the particle surface coated with ammonium sulfate. As a result of calculating the ammonium sulfate content of the ammonium persulfate particle composition, it was 1.75% by weight. Also, as a result of conducting a combustion test, all 6 measurements were non-combustible during the 6 measurements.

[0032] Example 3 The same operation as in Example 2 was carried out except that the amount of the saturated ammonium sulfate aqueous solution added as a non-combustible material solution was 9.4 g. As a result of calculating the ammonium sulfate content of the obtained ammonium persulfate particle composition, it was 1.94% by weight, and in the combustion test, all 6 measurements were non-combustible during the 6 measurements.

[0033] Example 4 400 g of ammonium persulfate (manufactured by Fuji Film Wako Pure Chemical Industries, Ltd., purity 98.0% or higher, particle content not passing through a sieve with an opening of 45 μm and passing through a sieve with an opening of 2000 μm: 99.0% by weight or higher) was added to a 1000 mL beaker, and then 9.4 g of a saturated ammonium sulfate aqueous solution as a non-combustible material solution was added. After that, stirring and mixing were carried out for 1 hour using two inclined paddle blades (3 stages, blade inclination angle 45°, blade diameter 75 mm, blade width 12.5 mm, blade pitch: 30 mm) to obtain a wet cake of the ammonium persulfate particle composition. Subsequently, the obtained wet cake was vacuum dried using a shelf dryer under the conditions of 40 °C and 10 Torr to obtain an ammonium persulfate composition in which ammonium sulfate was coated on the particle surface. As a result of calculating the ammonium sulfate content of the ammonium persulfate particle composition, it was 1.66% by weight. Also, as a result of conducting a combustion test, all 6 measurements were non-combustible during the 6 measurements.

[0034] Example 5 The same operations as in Example 1 were carried out except that the amount of the saturated ammonium sulfate aqueous solution added as the non-combustible material solution was 9.4 g. As a result of calculating the ammonium sulfate content of the obtained ammonium persulfate particle composition, it was 1.80% by weight, and in the combustion test, all 6 measurements were non-combustible during the 6 measurements.

[0035] Example 6 The same operations as in Example 2 were carried out except that the amount of the saturated ammonium sulfate aqueous solution added as the non-combustible material solution was 8.4 g. As a result of calculating the ammonium sulfate content of the obtained ammonium persulfate particle composition, it was 1.61% by weight, and in the combustion test, 6 out of 10 measurements were non-combustible and 4 were combustible.

[0036] Example 7 The same operations as in Example 1 were carried out except that the amount of the saturated ammonium sulfate aqueous solution added as the non-combustible material solution was 8.4 g. As a result of calculating the ammonium sulfate content of the obtained ammonium persulfate particle composition, it was 1.55% by weight, and in the combustion test, 6 out of 10 measurements were non-combustible and 4 were combustible.

[0037] Example 8 The same operations as in Example 2 were carried out except that 15.8 g of a saturated potassium chloride aqueous solution was added instead of the saturated ammonium sulfate aqueous solution as the non-combustible material solution, and an ammonium persulfate particle composition having the particle surface coated with potassium chloride was obtained. As a result of calculating the total value of the ammonium sulfate and potassium chloride contents of the obtained ammonium persulfate particle composition, it was 1.70% by weight, and in the combustion test, all 6 measurements were non-combustible.

[0038] Example 9 The same operations as in Example 2 were carried out except that 15.1 g of a saturated sodium chloride aqueous solution was added instead of the saturated ammonium sulfate aqueous solution as the non-combustible material solution, and an ammonium persulfate particle composition having the particle surface coated with sodium chloride was obtained. As a result of calculating the total value of the ammonium sulfate and sodium chloride contents of the obtained ammonium persulfate particle composition, it was 1.67% by weight, and in the combustion test, all 6 measurements were non-combustible.

[0039] Comparative Example 1 100 g of ammonium persulfate (manufactured by Fuji Film Wako Pure Chemical Industries, purity 98.0% or more, content of particles not passing through a 45-μm sieve and passing through a 2000-μm sieve 99.0% by weight or more) was not mixed with the non-combustible material solution, and after vacuum drying under the conditions of 40 °C and 10 Torr using a shelf dryer, a combustion test was carried out. As a result, all 5 measurements were combustible (combustion time: 29 seconds).

[0040] Comparative Example 2 100 g of ammonium persulfate (manufactured by Mitsubishi Gas Chemical, purity 98.0% or more, content of particles not passing through a 45-μm sieve and passing through a 2000-μm sieve 99.0% by weight or more) was not mixed with the non-combustible material solution, and after vacuum drying under the conditions of 40 °C and 10 Torr using a shelf dryer, a combustion test was carried out. As a result, all 5 measurements were combustible (combustion time: 40 seconds).

[0041] Comparative Example 3 100 g of ammonium persulfate (manufactured by ADEKA, purity 98.0% or higher, containing 99.0% by weight or more of particles that do not pass through a 45-μm sieve and pass through a 2000-μm sieve) was vacuum-dried under the conditions of 40°C and 10 Torr using a shelf dryer without mixing with a non-combustible material solution, and then a combustion test was conducted. As a result, all 5 measurements were combustible (combustion time: 40 seconds).

[0042] Comparative Example 4 The same operations as in Example 2 were carried out except that the amount of the saturated ammonium sulfate aqueous solution added as the non-combustible material solution was 7.5 g. As a result of calculating the ammonium sulfate content of the obtained ammonium persulfate particle composition, it was 1.52% by weight. In the combustion test, 2 out of 7 measurements were non-combustible and 5 were combustible (combustion time: 28 seconds).

[0043] Comparative Example 5 The same operations as in Example 1 were carried out except that the amount of the saturated ammonium sulfate aqueous solution added as the non-combustible material solution was 7.5 g. As a result of calculating the ammonium sulfate content of the obtained ammonium persulfate particle composition, it was 1.51% by weight. In the combustion test, 4 out of 9 measurements were non-combustible and 5 were combustible (combustion time: 30 seconds).

[0044] Comparative Example 6 400 g of ammonium persulfate powder (manufactured by FUJIFILM Wako Pure Chemical Corporation, purity 98.0% or higher, containing 99.0% by weight or more of particles that do not pass through a 45-μm sieve and pass through a 2000-μm sieve) and 4.0 g of ammonium sulfate as a non-combustible material were added to a 1000-mL Erlenmeyer flask with a stopper, inverted with the bottom cut off. Then, stirring and mixing were carried out for 1 hour using a screw blade (left-handed, blade outer diameter 40 mm, blade inner diameter 18 mm, blade pitch 40 mm, blade thickness 5 mm). The obtained mixture was vacuum-dried under the conditions of 40°C and 10 Torr using a shelf dryer to obtain a mixture of ammonium persulfate and ammonium sulfate. As a result of calculating the ammonium sulfate content of the obtained mixture of ammonium persulfate and ammonium sulfate, it was 1.92% by weight. In the combustion test, all 5 measurements were combustible (combustion time: 29 seconds).

[0045] Comparative Example 7 400 g of ammonium persulfate powder (manufactured by FUJIFILM Wako Pure Chemical Industries, Ltd., purity 98.0% or higher, particle content not passing through a sieve with an opening of 45 μm and passing through a sieve with an opening of 2000 μm 99.0% by weight or higher) and 4.0 g of ammonium sulfate as a non-combustible material were added to a 1000 mL eggplant flask, and then rotated using an evaporator for 1 hour of mixing. The obtained mixture was vacuum dried using a shelf dryer under the conditions of 40°C and 10 Torr to obtain a mixture of ammonium persulfate and ammonium sulfate. As a result of calculating the ammonium sulfate content of the obtained mixture of ammonium persulfate and ammonium sulfate, it was 1.91% by weight, and in the combustion test, all 5 measurements were combustible (combustion time: 29 seconds) out of 5 measurements.

Industrial Applicability

[0046] According to the present invention, a persulfate particle composition having a particle surface coated with a non-combustible material can be produced. This persulfate particle composition is non-combustible, does not fall under Class 1 (oxidizing solid) of the Fire Service Act of Japan, and is easy to handle in production, transportation, storage, and use.

Claims

1. A persulfate particle composition in which the surface of the persulfate particles is coated with a non-combustible material, the non-combustible material being contained in an amount of 1.55% to 2.00% by weight based on the weight of the persulfate particle composition.

2. The persulfate particle composition according to claim 1, wherein the non-combustible material is at least one selected from inorganic compounds and organic compounds that are inert to persulfates.

3. The persulfate particle composition according to claim 1, wherein the non-combustible material is a water-soluble inorganic compound.

4. The persulfate particle composition according to claim 3, wherein the non-combustible material is at least one selected from ammonium sulfate, sodium sulfate, potassium sulfate, ammonium chloride, potassium chloride, sodium chloride, and calcium chloride.

5. The persulfate particle composition according to claim 1, wherein the persulfate is at least one selected from ammonium persulfate, potassium persulfate, and sodium persulfate.

6. The persulfate particle composition according to claim 1, which does not fall under Class 1 Dangerous Goods (Oxidizing Solids) of the Fire Service Act of Japan.

7. The persulfate particle composition according to claim 1, which does not catch fire or ignite when a heated nichrome wire is brought into contact with a mixture mixed with wood powder for 10 seconds in a combustion test, which is a determination test method for Class 1 Dangerous Goods (Oxidizing Solids) of the Fire Service Act of Japan.

8. A method for producing a persulfate particle composition, comprising mixing a non-combustible material dissolved or dispersed in a solvent and persulfate particles, and then removing the solvent.

9. The method for producing a persulfate particle composition according to claim 8, wherein the non-combustible material is at least one selected from inorganic compounds and organic compounds that are inert to persulfates.

10. The method for producing a persulfate particle composition according to claim 9, wherein the non-combustible material is at least one selected from ammonium sulfate, sodium sulfate, potassium sulfate, ammonium chloride, potassium chloride, sodium chloride, and calcium chloride.

11. The method for producing a persulfate particle composition according to claim 8, wherein the solvent is removed by drying.