JPWO2014156875A1 - Solid oxygen generating composition - Google Patents

Abstract

To provide an oxygen generating composition capable of obtaining a sufficient oxygen release amount and maintaining a stable water quality environment even if the calcium peroxide content is small, and a method for producing the same. An oxygen generating composition comprising a molded body containing 2 to 20% calcium peroxide, 2 to 30% calcium carbonate, 2 to 30% calcium hydroxide, and 30 to 80% calcium dihydrogen phosphate, the phosphoric acid Calcium dihydrogen is a particle having an average particle diameter of 150 × 10 −6 to 800 × 10 −6 m, and calcium dihydrogen phosphate particles having a maximum particle diameter of less than 106 × 10 −6 m are based on the weight of calcium dihydrogen phosphate. It is an oxygen generating composition and its manufacturing method characterized by containing 10 to 40% of range.

Description

  The present invention provides an ornamental aquatic organism that gradually releases oxygen by contact with water in an aquarium such as an aquarium for appreciation fish, an aquarium for fish, an aquarium for transporting live fish, etc. The present invention relates to an oxygen generating composition for maintaining a water quality environment suitable for rearing fish and transporting live fish, and a method for producing the same.

  Conventionally, a solid oxygen generating composition containing calcium peroxide has been used to increase the oxygen concentration in water for the purpose of maintaining a water quality environment suitable for nurturing ornamental aquatic organisms such as ornamental fish and transporting live fish. (Patent Document 1). This solid oxygen generating composition further contains calcium dihydrogen phosphate for the purpose of maintaining the pH at the time of charging into water from neutral to acidic.

JP-A-8-301605

Patent Document 1 describes mixing calcium dihydrogen phosphate prepared with a particle size of 0.1 to 1 mm as a raw material powder with respect to the particle size of calcium dihydrogen phosphate. The adjustment method is not described.
However, if the average particle size of the calcium dihydrogen phosphate is simply set to 0.1 to 1 mm, the dispersion of calcium dihydrogen phosphate will vary when it is poured into water. In the case of calcium dihydrogen phosphate containing a lot of coarse particles, it is difficult for dissolution to proceed in water and obstructs the contact between the calcium peroxide component in the solid oxygen generating composition and water. The amount is not obtained. Therefore, if the calcium peroxide content is increased in order to obtain a desired oxygen release amount, the pH in water tends to change abruptly this time, and is particularly suitable for medaka, freshwater shrimp, etc. that dislike rapid changes in water quality such as pH. There wasn't.

  An object of the present invention is to solve the above-mentioned problems, and an oxygen generating composition capable of obtaining a sufficient oxygen release amount and maintaining a stable water quality environment even when the calcium peroxide content is small. Product and a method for manufacturing the same.

In order to solve the above problems, the present inventor has made various studies, and as a result, calcium peroxide 2 to 20%, calcium carbonate 2 to 30%, calcium hydroxide 2 to 30%, and calcium dihydrogen phosphate 30. An oxygen generating composition comprising a molded body containing ˜80%, wherein the calcium dihydrogen phosphate is a particle having an average particle size of 150 × 10 ^{−6 to} 800 × 10 ⁻⁶ m and a maximum particle size of 106 An oxygen generating composition comprising calcium dihydrogen phosphate particles of less than × 10 ⁻⁶ m in a range of 10 to 40% based on the weight of calcium dihydrogen phosphate is more effective than conventional calcium peroxide. The reaction of water and water progresses, and even when the calcium peroxide content is small, a sufficient oxygen release amount can be obtained and a stable water quality environment can be maintained, and the present invention is completed. It led to.

That is, according to the present invention,
[1] An oxygen generating composition comprising a molded body containing 2 to 20% calcium peroxide, 2 to 30% calcium carbonate, 2 to 30% calcium hydroxide, and 30 to 80% calcium dihydrogen phosphate, The calcium dihydrogen phosphate is a particle having an average particle diameter of 150 × 10 ^{−6 to} 800 × 10 ⁻⁶ m, and the calcium dihydrogen phosphate particles having a maximum particle diameter of less than 106 × 10 ⁻⁶ m An oxygen generating composition characterized by containing in the range of 10 to 40% based on the weight of calcium hydrogen;
[2] The calcium dihydrogen phosphate contains 95% or more of calcium dihydrogen phosphate particles having a maximum particle size of less than 1000 × 10 ⁻⁶ m, based on the weight of calcium dihydrogen phosphate. The oxygen generating composition according to claim 1,
[3] The calcium dihydrogen phosphate is a calcium dihydrogen phosphate particle having a maximum particle size of less than 106 × 10 ⁻⁶ m, a minimum particle size of 106 × 10 ⁻⁶ m or more, and an average particle size of 200 × 10. The oxygen according to [1] or [2], wherein ^{-6 to} 800 × 10 ⁻⁶ m of calcium dihydrogen phosphate particles are contained in a ratio of 10:90 to 40:60 on a weight basis. Generating composition,
[4] A method for producing an oxygen generating composition,
Calcium dihydrogen phosphate particles having an average particle diameter of 150 × 10 ^{−6 to} 800 × 10 ⁻⁶ m and a maximum particle diameter of less than 106 × 10 ⁻⁶ m are 10 to 40 based on the weight of calcium dihydrogen phosphate. Preparation step (A) for preparing calcium dihydrogen phosphate containing in the range of%
Calcium peroxide 2 to 20% by weight, calcium carbonate 2 to 30% by weight, calcium hydroxide 2 to 30% by weight, and calcium dihydrogen phosphate 30 to 80% by weight obtained in the preparation step (A) are mixed. Then, a mixing step (B) for obtaining a mixture, and a molding step (C) for molding the mixture obtained in the mixing step to obtain an oxygen generating composition comprising a molded body
A method for producing an oxygen generating composition, comprising:
[5] The preparation step (A)
i) Step of preparing calcium dihydrogen phosphate particles having a maximum particle size of less than 106 × 10 ⁻⁶ m as a first powder ii) The minimum particle size is 106 × 10 ⁻⁶ m or more and the average particle size is 200 × 10 ⁻ A step of preparing ^{6 to} 800 × 10 ⁻⁶ m of calcium dihydrogen phosphate particles as a second powder, and iii) the first powder and the second powder on a weight basis of 10:90 to 40:60. A method for producing the oxygen generating composition according to [4], comprising a step of mixing at a ratio of
[6] The calcium dihydrogen phosphate obtained in the preparation step (A) contains 95% or more of calcium dihydrogen phosphate particles having a maximum particle diameter of less than 1000 × 10 ⁻⁶ m based on the weight of calcium dihydrogen phosphate. The method for producing an oxygen generating composition according to [4] or [5],
About.

  The present invention provides an oxygen generating composition capable of obtaining a sufficient oxygen release amount and maintaining a stable water quality environment even when the calcium peroxide content is small, and a method for producing the same. .

  In the oxygen generating composition of the present invention, the above components are blended in the above range, and the particle size of the above calcium dihydrogen phosphate is within the above range, so that the calcium dihydrogen phosphate dissolves quickly in water. Therefore, the calcium peroxide and water react with each other efficiently and stably without releasing the contact between calcium peroxide and water in the molded body, thereby releasing oxygen bubbles and releasing a sufficient amount of oxygen. be able to.

1. Oxygen generating composition The oxygen generating composition of the present invention contains 2 to 20% by weight of calcium peroxide, 2 to 30% by weight of calcium carbonate, 2 to 30% by weight of calcium hydroxide, and 30 to 80% by weight of calcium dihydrogen phosphate. It consists of a molded body. The weight% is based on the weight when the oxygen generating composition is 100% by weight.

  The oxygen releasing component of the present invention is calcium peroxide. When calcium peroxide alone is introduced into water, it reacts rapidly with water, and the amount of dissolved oxygen in water increases rapidly, so the water quality environment changes abruptly. Then, in addition to calcium peroxide, a rapid reaction between calcium peroxide and water can be suppressed by blending calcium carbonate and calcium hydroxide so as to fall within the above range. As a result, calcium peroxide reacts stably in water and releases oxygen gradually over a long period of time, so that dissolved oxygen in water can be increased stably.

  Furthermore, by adding calcium dihydrogen phosphate with a particle size in the above range to this, the pH of the water in which the oxygen generating composition is added is maintained on the neutral to acidic side without adversely affecting the survival of animals and plants. And can maintain a stable water quality environment.

  In the present invention, calcium peroxide is blended so as to contain 2 to 20% by weight. If the calcium peroxide is less than 2% by weight, the amount of oxygen released into water is not sufficient, and if it is more than 20% by weight, it reacts rapidly with water and the water quality environment changes rapidly. In order to obtain a sufficient oxygen release amount while maintaining a stable water quality environment, 2 to 15% by weight is preferable, and 3 to 10% by weight is more preferable.

  In this invention, it mix | blends so that a calcium carbonate may contain 2-30 weight% and a calcium hydroxide 2-30 weight%. When calcium carbonate and calcium hydroxide are less than 2% by weight, calcium peroxide reacts rapidly with water, and the water quality environment changes abruptly. When the amount is more than 30% by weight, the reaction between calcium peroxide and water is excessively suppressed, and a sufficient oxygen release amount cannot be obtained. In order to enhance the effect of the present invention, 2 to 25% by weight is preferable and 3 to 20% by weight is more preferable.

  In this invention, it mix | blends so that calcium dihydrogen phosphate may be contained 30 to 80weight%. If the amount of calcium dihydrogen phosphate is less than 30% by weight, the pH in the water into which the oxygen generating composition has been added increases. If it is more than 80% by weight, the reaction between calcium peroxide and water is excessively suppressed. As a result, a sufficient oxygen release amount cannot be obtained. In order to further enhance the effect of the present invention, 35 to 75% by weight is preferable, and 40 to 70% by weight is more preferable.

In the present invention, calcium dihydrogen phosphate is a particle having an average particle diameter of 150 × 10 ^{−6 to} 800 × 10 ⁻⁶ m, and calcium dihydrogen phosphate particles having a maximum particle diameter of less than 106 × 10 ⁻⁶ m. It is contained in the range of 10 to 40% based on the weight of calcium dihydrogen phosphate.
The average particle diameter of the calcium dihydrogen phosphate of the present invention is measured by a sieving analysis method. Specifically, a low-tap type sieve shaker (manufactured by Tokyo Glass Instrument Co., Ltd., S-1 type) has a nominal opening of 3350, 2000, 1000, 850, 710, 600, 500, 425, 300, 212, JIS test sieves (JIS Z8801) of 150, 106, 75, 45 (all units are “× 10 ⁻⁶ m”) are stacked in order from the bottom of the sieve with the smallest sieve mesh, and from above, calcium dihydrogen phosphate 100 After adding ^10-6 kg and shaking for 5 minutes, the weight of calcium dihydrogen phosphate remaining on each sieve is measured. The accumulated residual rate is obtained from the residual rate in each sieve, and is subtracted from 100% to calculate the passing weight percentage. Plotting on the logarithmic probability paper with the passing weight percentage on the vertical axis and the nominal opening of the sieve on the horizontal axis, the value on the horizontal axis at which the passing weight percentage is 50% is read, and this is taken as the average particle diameter.
The particles having a maximum particle size of less than 106 × 10 ⁻⁶ m are particles that have passed through a sieve having a nominal aperture of 106 × 10 ⁻⁶ m.

By setting the average particle diameter of the calcium dihydrogen phosphate particles in the range of 150 × 10 ^{−6 to} 800 × 10 ⁻⁶ m, the calcium dihydrogen phosphate dissolves rapidly when introduced into water, and oxygen Since the calcium peroxide component in the generated composition molded body is likely to react with water, a sufficient oxygen release amount can be obtained. If the average particle size is smaller than 150 × 10 ⁻⁶ m, the fine particles aggregate and dissolution does not proceed, which is not preferable because the reaction between the calcium peroxide component contained in the molded body and water is hindered. Moreover, since the press moldability at the time of producing a molded object is deteriorated, it is not preferable. When the average particle size is larger than 800 × 10 ⁻⁶ m, the dissolution of coarse particles does not proceed and the reaction between the calcium peroxide component contained in the molded body and water is hindered, which is not preferable.

Further, by containing calcium dihydrogen phosphate particles having a maximum particle size of less than 106 × 10 ⁻⁶ m in a range of 10 to 40% based on the weight of calcium dihydrogen phosphate, dihydrogen phosphate when introduced into water. Since calcium dissolves rapidly and the calcium peroxide component in the oxygen-generating composition molded body is likely to react with water, a sufficient oxygen release amount can be obtained. In addition, fine particles react rapidly in water, and a rapid increase in pH due to calcium peroxide can be suppressed to maintain water quality suitable for a living body. If the content ratio of the particles is less than 10%, the number of particles that rapidly react with water is reduced, and the effect of suppressing the increase in pH is reduced. When the content ratio of the particles is larger than 40%, the fine particles are aggregated and the dissolution does not proceed, and the reaction between the calcium peroxide component contained in the molded body and water is hindered. Moreover, since the press moldability at the time of producing a molded object is deteriorated, it is not preferable. In addition, there is no restriction ^| limiting in particular in the minimum particle diameter of the said particle | grain, You may contain the particle ^| grains less than 45 * 10 <^-6> m.

Furthermore, the calcium dihydrogen phosphate preferably contains 95% or more of calcium dihydrogen phosphate particles having a maximum particle diameter of less than 1000 × 10 ⁻⁶ m based on the weight of calcium dihydrogen phosphate. Here, the particles having a maximum particle diameter of less than 1000 × 10 ⁻⁶ m are particles that have passed through a sieve having a nominal opening of 1000 × 10 ⁻⁶ m. When the content ratio of the calcium dihydrogen phosphate particles having a maximum particle diameter of less than 1000 × 10 ⁻⁶ m is 95% or more based on the weight of calcium dihydrogen phosphate, the particles are more rapidly dissolved. As a result, the calcium peroxide component contained in the molded body is more likely to react with water. When the content of calcium dihydrogen phosphate particles having a maximum particle size of less than 1000 × 10 ⁻⁶ m is less than 95% based on the weight of calcium dihydrogen phosphate, dissolution of coarse particles does not proceed and is contained in the molded product. This is not preferable because it interferes with the reaction between the calcium peroxide component and water.

In order to obtain the above-mentioned preferable calcium dihydrogen phosphate, a commercially available product may be used as long as the particle size is in the above range, but calcium dihydrogen phosphate particles having a maximum particle size of less than 106 × 10 ⁻⁶ m are used. First powder, calcium dihydrogen phosphate particles having a minimum particle diameter of 106 × 10 ⁻⁶ m or more and an average particle diameter of 200 × 10 ^{−6 to} 800 × 10 ⁻⁶ m are used as the second powder, and The first and second powders may be calcium dihydrogen phosphate containing 10:90 to 40:60 on a weight basis. The particles having a minimum particle diameter of 106 × 10 ⁻⁶ m or more are particles that do not pass through a sieve having a nominal aperture of 106 × 10 ⁻⁶ m. When the second powder has an average particle size of 200 × 10 ^{−6 to} 800 × 10 ⁻⁶ m, the dissolution of calcium hydrogen phosphate particles proceeds more rapidly, and the calcium peroxide component contained in the molded body is more water than water. It becomes easy to react. If the average particle size of the second powder is smaller than 200 × 10 ⁻⁶ m, the fine particles aggregate and the dissolution does not proceed, preventing the reaction between the calcium peroxide component contained in the molded body and water. Therefore, it is not preferable. Moreover, since the press moldability at the time of producing a molded object is deteriorated, it is not preferable. When the average particle size of the second powder is larger than 800 × 10 ⁻⁶ m, the dissolution of coarse calcium dihydrogen phosphate particles does not proceed, and the reaction between the calcium peroxide component contained in the molded body and water occurs. It is not preferable because it interferes. The maximum particle size of the second powder is not particularly limited, but is preferably less than 2000 × 10 ⁻⁶ m.

As the first powder and the second powder, commercially available powders may be used as long as the particle size is in the above range, but the commercially available powder may be adjusted in particle size through a sieving step and a pulverizing step. Specifically, commercially available calcium dihydrogen phosphate powder having an average particle size of about 100 × 10 ^{−6 to} 2000 × 10 ⁻⁶ m is prepared, and a low-tap type sieve shaker (manufactured by Tokyo Glass Instruments Co., Ltd., S-1 type) and a sieve having a nominal mesh size of 106 × 10 ⁻⁶ m for JIS test (JIS Z8801) may be used as a first powder.
Furthermore, a commercially available calcium dihydrogen phosphate powder was prepared in the same manner as described above, and after pulverization using a ball mill or the like, the powder was sieved with a sieve having a nominal aperture of 106 × 10 ⁻⁶ m, and the average particle diameter was in the above range. The powder on the sieve may be the second powder.

The oxygen generating composition of the present invention may contain a binder as a powder binder to such an extent that the elution of the oxygen generating component is not hindered. Examples of the binder include an inorganic binder and an organic binder. Examples of the inorganic binder include sodium silicate and clay, and examples of the organic binder include ethyl cellulose and hydroxypropyl cellulose.
As the binder of the present invention, an organic binder is preferable.

  The content of the binder is preferably blended in the oxygen generating composition so as to be 0.05 to 5% by weight. If it is such content, the moldability at the time of shaping | molding will improve, without impairing oxygen generation efficiency.

  The method for obtaining the raw materials for each component of the oxygen generating composition of the present invention is not particularly limited, but as calcium peroxide, Nippon Peroxide, Otsuka Chemical, Tomita Pharmaceutical Co., Ltd., etc., as calcium hydroxide, Inoue lime Industrial, Ueda Lime Manufacturing, Adachi Lime Industry, Omi Chemical Industry, Okutama Industry, Maruo Calcium Co., etc. Kao Kogyo and Toyo Denka Kogyo Co., Ltd., as well as calcium dihydrogen phosphate, commercially available products such as Odawara Kasei, Taiyo Chemical Industry, Matsuo Pharmaceutical Industry, Onoda Chemical Industry, Taihei Chemical Industry, and Yoneyama Chemical Industry Co., Ltd. Can be used.

The average particle size of each powder raw material of the component other than calcium dihydrogen phosphate in the oxygen generating composition of the present invention is not particularly limited, but in order to elute oxygen into water efficiently, the average particle size is 100 × 10 ^−. A powder of ^{6 to} 1000 × 10 ⁻⁶ m is preferred. The average particle diameter here is measured by a sieving analysis method in the same manner as the average particle diameter of calcium dihydrogen phosphate.

The oxygen generating composition of the present invention comprises a molded body containing each of the above components, and includes an arbitrary molded body such as a press-molded molded body. The molding pressure at the time of molding is a pressure of 1 to 100 MPa and a compact density in the range of 1.20 × 10 ^{3 to} 3.00 × 10 ³ kg / m ³ in order to elute oxygen components into water efficiently. A molded body is preferred. The molding pressure is more preferably 5 to 80 MPa, and even more preferably 10 to 50 MPa. The compact density is more preferably 1.40 × 10 ^{3 to} 2.50 × 10 ³ kg / m ³ , and even more preferably 1.50 × 10 ^{3 to} 2.00 × 10 ³ kg / m ³ .

  In addition, examples of the shape of the oxygen generating composition of the present invention include, but are not limited to, a disc shape, a cube shape, a rectangular parallelepiped shape, a polyhedron shape, and a polygonal plate shape.

In the present invention, the surface area and aspect ratio of the outer shape of the molded body are not particularly limited, but the surface area is 500 × 10 ^{−6 to} 3000 × 10 ⁻⁶ m ² and the aspect ratio is 1.0 to 4.5. Is preferred. The surface area is more preferably 510 × 10 ^{−6 to} 2900 × 10 ⁻⁶ m ² , and even more preferably 520 × 10 ^{−6 to} 2800 × 10 ⁻⁶ m ² . The aspect ratio is more preferably 1.1 to 4.4, and even more preferably 1.1 to 4.3. Here, the aspect ratio means the diameter φ of the molded body divided by the thickness t of the molded body, and the diameter φ is the length of the major axis of the circular surface in the shape of a disk. In the case of a polygonal plate, the length of the longest diagonal line in the widest surface of the molded body.

2. Method for producing oxygen generating composition The method for producing the oxygen generating composition of the present invention comprises:
Preparation process (A)
Calcium dihydrogen phosphate particles having an average particle diameter of 150 × 10 ^{−6 to} 800 × 10 ⁻⁶ m and a maximum particle diameter of less than 106 × 10 ⁻⁶ m are 10 to 40 based on the weight of calcium dihydrogen phosphate. % Preparation process mixing step (B) for preparing calcium dihydrogen phosphate containing in the range
Calcium peroxide 2 to 20% by weight, calcium carbonate 2 to 30% by weight, calcium hydroxide 2 to 30% by weight, and calcium dihydrogen phosphate 30 to 80% by weight obtained in the preparation step (A) are mixed. A mixing step to obtain a mixture, and a molding step (C)
It is a manufacturing method including the shaping | molding process which shape | molds the mixture obtained at the said mixing process (B), and obtains the oxygen generating composition which consists of a molded object.

  The weight% in the mixing step of the production method of the present invention is based on the weight when the oxygen generating composition is 100% by weight.

  By the production method of the present invention, even if the calcium peroxide content is small, oxygen can be distributed in a well-balanced manner, a sufficient oxygen release amount can be obtained, and a stable water quality environment can be maintained. An oxygen generating composition can be produced.

  Hereafter, the manufacturing method of the oxygen generating composition of this invention is demonstrated in detail.

  In the production method of the present invention, examples of suitable raw materials include the compounds exemplified in the oxygen generating composition of the present invention.

  Although the acquisition method of each raw material used in the manufacturing method of this invention is not specifically limited, The commercial item illustrated in the oxygen generating composition of this invention can be used.

The average particle diameter in the production method of the present invention is measured by a sieving analysis method in the same manner as the oxygen generating composition of the present invention. The average particle diameter of the above raw materials other than calcium dihydrogen phosphate used in the production method of the present invention is not particularly limited, but powder having an average particle diameter of 100 × 10 ^{−6 to} 1000 × 10 ⁻⁶ m is preferable. In addition, you may use a sorter, a grinder, etc. so that an average particle diameter may enter into the said range.

The preparation step (A) in the production method of the present invention is particles having an average particle size of 150 × 10 ^{−6 to} 800 × 10 ⁻⁶ m, and calcium dihydrogen phosphate particles having a maximum particle size of less than 106 × 10 ⁻⁶ m. Is a preparatory step for preparing calcium dihydrogen phosphate containing 10 to 40% of calcium dihydrogen phosphate in terms of weight.

In the production method of the present invention, the preparation step (A) is specifically the preparation step (A ′).
10 to 40% of calcium dihydrogen phosphate particles having an average particle size of 150 × 10 ^{−6 to} 800 × 10 ⁻⁶ m and a maximum particle size of less than 106 × 10 ⁻⁶ m based on the weight of calcium dihydrogen phosphate. A preparation step of preparing calcium dihydrogen phosphate containing a range of
i) Step of preparing calcium dihydrogen phosphate particles having a maximum particle size of less than 106 × 10 ⁻⁶ m as a first powder ii) The minimum particle size is 106 × 10 ⁻⁶ m or more and the average particle size is 200 × 10 ⁻ A step of preparing ^{6 to} 800 × 10 ⁻⁶ m of calcium dihydrogen phosphate particles as a second powder, and iii) the first powder and the second powder on a weight basis of 10:90 to 40:60. It is good also as a process including the process mixed in the ratio.

In the step (A ′) i) ii), commercially available calcium dihydrogen phosphate may be used. For example, in the step i), commercially available calcium dihydrogen phosphate powder having an average particle size of about 100 × 10 ^{−6 to} 2000 × 10 ⁻⁶ m is obtained by using a low-tap type sieve shaker (manufactured by Tokyo Glass Instruments Co., Ltd., S-1 type) and a sieve having a nominal aperture of 106 × 10 ⁻⁶ m for JIS test (JIS Z8801) may be used as a first powder. Further, for example, in the step ii), commercially available calcium dihydrogen phosphate having an average particle diameter of 100 × 10 ^{−6 to} 2000 × 10 ⁻⁶ m is pulverized using a ball mill or the like, and then the nominal aperture is 106 × 10. ^It is good also considering the powder on the sieve made into the range of the said average particle diameter as a 2nd powder by sieving with -6m sieve. In this case, the powder having passed through the sieve of nominal opening 106 × ^{10 -6} m, the maximum particle size can be said that 106 × ^{10 -6} m below the powder, the sieve of nominal opening 106 × ^{10 -6} m The powder that does not pass can be said to be a powder having a minimum particle size of 106 × 10 ⁻⁶ m or more.

In the production method of the present invention, particles having an average particle diameter of 150 × 10 ^{−6 to} 800 × 10 ⁻⁶ m and a maximum particle diameter of less than 106 × 10 ⁻⁶ m are 10 to 40% based on the weight of calcium dihydrogen phosphate. It is desirable that the calcium dihydrogen phosphate contained in the above range contains 95% or more of particles having a maximum particle diameter of less than 1000 × 10 ⁻⁶ m based on the weight of calcium dihydrogen phosphate. In order to contain 95% or more of particles having a maximum particle size of less than 1000 × 10 ⁻⁶ m on the basis of the weight of calcium dihydrogen phosphate, for example, by easily adjusting the mixing ratio of the first powder and the second powder, Can be set. The weight percentage of particles having a maximum particle size of less than 1000 × 10 ⁻⁶ m can be measured and calculated using a sieving analysis method. In this case, the powder containing 95% or more by weight percentage of particles having passed through a sieve having a nominal aperture of 1000 × 10 ⁻⁶ m is 95% or more of particles having a maximum particle diameter of less than 1000 × 10 ⁻⁶ m. It can be said that it contains powder.

  The mixing step (B) of the present invention comprises calcium peroxide 2 to 20% by weight, calcium carbonate 2 to 30% by weight, calcium hydroxide 2 to 30% by weight, and calcium dihydrogen phosphate obtained in the preparation step A. 30 to 80% by weight is mixed to obtain a mixture.

  In the production method of the present invention, calcium peroxide, calcium carbonate, calcium hydroxide and calcium dihydrogen phosphate are contained in the oxygen generating composition in an amount of 2 to 15% by weight of calcium peroxide, 2 to 25% by weight of calcium carbonate, water. It is preferable to contain 2 to 25% by weight of calcium oxide and 35 to 75% by weight of calcium dihydrogen phosphate. Further, the oxygen generating composition contains 3 to 10% by weight of calcium peroxide, 3 to 20% by weight of calcium carbonate, 3 to 20% by weight of calcium hydroxide, and 40 to 70% by weight of calcium dihydrogen phosphate. Is more preferable.

  In the production method of the present invention, even if the purity of the raw material is not 100%, the raw materials are blended so that each compound has a content within the range of the present invention, that is, the content of the present invention is set according to the purity of the raw material. Raw materials may be added to.

  In the mixing step of the production method of the present invention, the mixing method is not particularly limited, but dry mixing is preferable. The dry mixing may be performed using a mixing stirrer such as a general dry mixer, or may be manually mixed in a predetermined container. The mixing speed, mixing time, and the like are not particularly limited, but may be mixed uniformly.

  In the mixing step, a granulation step may be included after each mixing step.

  Furthermore, in the production method of the present invention, further components can be added within a range not impairing the effects of the present invention. Additional components include, but are not limited to, binders, pigments and the like.

  In the mixing step, a binder may be added and mixed in order to stably elute active ingredients and improve moldability. Examples of the binder include the compounds exemplified as the binder in the oxygen generating composition of the present invention. In the production method of the present invention, an organic binder is preferable. When an organic binder is added and mixed, an alcohol such as ethyl alcohol may be added and mixed. In that case, it is preferable to dry after mixing.

  The binder content is preferably blended in the oxygen generating composition so as to be 0.01 to 5% by weight. If it is such content, the moldability at the time of shaping | molding will improve.

  Although there is no restriction | limiting in particular in the addition amount of alcohol in the case of using an organic binder, It is preferable that it is 0.5 weight part-10 weight part with respect to 1 weight part of binder, and it is 1 weight part-5 weight part. Is more preferable.

Although the shaping | molding method in the said shaping | molding process (C) of this invention is not restrict | limited in particular, Press molding etc. are mentioned, Arbitrary shaping | molding apparatuses and a shaping die suitable for each shaping | molding can be used. About the press molding in the production method of the present invention, the compact density is 1.20 × 10 ^{3 to} 3.00 × 10 ³ kg / m ^{3 in} a range of molding pressure of 1 to 100 MPa using a uniaxial press machine or the like. It is desirable to mold so as to be in the range. The molding pressure is more preferably 5 to 80 MPa, and even more preferably 10 to 50 MPa. The compact density is more preferably 1.40 × 10 ^{3 to} 2.50 × 10 ³ kg / m ³ , and even more preferably 1.50 × 10 ^{3 to} 2.00 × 10 ³ kg / m ³ .

The shape of the molded body in the molding step of the present invention may be any shape such as a disk shape, a cubic shape, a rectangular parallelepiped shape, a polygonal plate shape, etc., but the outer surface area of the molded body is 500 to 3000 ×. It is preferable to manufacture the molded body so that the aspect ratio is in the range of 10 ⁻⁶ m ² and 1.0 to 4.5. The surface area of the molded body is more preferably 510 × 10 ^{−6 to} 2900 × 10 ⁻⁶ m ² , and even more preferably 520 × 10 ^{−6 to} 2800 × 10 ⁻⁶ m ² . The aspect ratio of the molded body is more preferably 1.1 to 4.4, and even more preferably 1.1 to 4.3. The size and material of the mold are not particularly limited as long as the surface area and the aspect ratio can be satisfied, and examples thereof include a mold.

  By the production method of the present invention, an oxygen generating composition comprising a molded body is obtained. The oxygen generating composition obtained by the production method of the present invention is preferably the oxygen generating composition of the present invention.

  The oxygen generating composition of the present invention and the oxygen generating composition obtained by the production method of the present invention are used in water, and can be used to maintain a breeding environment for aquatic organisms such as ornamental fish. Specifically, in order to maintain a stable water quality environment, a sufficient oxygen release amount can be obtained in aquarium water such as an aquarium for appreciation fish, an aquarium for fish, and a tank for transporting live fish. it can.

  EXAMPLES The present invention will be specifically described with reference to examples, but the present invention is not limited to the following examples.

[Evaluation method]
<pH>
Measured by putting one compact sample into ion-exchanged water 2 × 10 ⁻⁴ m ³ maintained at a water temperature of 20 ° C. ± 1 ° C., pH value at the start and dissolved oxygen amount, pH value after 6 hours and dissolved The amount of oxygen was measured using a pH · DO meter (WQC-22A manufactured by Toa Denpa Kogyo Co., Ltd.).

<Cumulative oxygen release>
Five molded sample samples were put into ion-exchanged water 5 × 10 ⁻³ m ³ whose water temperature was maintained at 17 ° C. ± 3 ° C., and the volume (m ³ ) of the amount of oxygen captured until 720 hours was measured. A value obtained by dividing the cumulative value of the measured volume by the sample mass was defined as the cumulative oxygen release amount (10 ⁻⁶ m ³ / kg).

<Average particle size>
The average particle size was measured by sieving analysis. A low tap type sieve shaker (Tokyo Glass Instruments Co., Ltd., Model S-1) has a nominal opening of 3350, 2000, 1000, 850, 710, 600, 500, 425, 300, 212, 150, 106, 75. , 45 (all units are “× 10 ⁻⁶ m”), JIS test sieves (JIS Z8801) are stacked in order from the bottom of the sieve with the smallest sieve mesh, and the calcium dihydrogen phosphate powder 100 × 10 ^{−3 from above.} After adding kg and shaking for 5 minutes, the weight of the powder remaining on each sieve was measured. The accumulation residual rate was calculated | required from the residual rate in each sieve, it was subtracted from 100%, and the passage weight percentage was computed. Plotted on logarithmic probability paper with the passing weight percentage as the vertical axis and the nominal aperture of the sieve as the horizontal axis, the value on the horizontal axis at which the passing weight percentage was 50% was read, and this was taken as the average particle diameter.

<Weight-based content of particles having a maximum particle size of less than 1000 × 10 ⁻⁶ m>
The weight-based content of particles having a maximum particle size of less than 1000 × 10 ⁻⁶ m was measured by a sieving analysis method. A JIS test sieve (JIS Z8801) having a nominal mesh size of 1000 × 10 ⁻⁶ m is set on a low tap type sieve shaker (manufactured by Tokyo Glass Instrument Co., Ltd., type S-1), and two phosphoric acid phosphates are added thereon. From the weight of the calcium dihydrogen phosphate particles that had been shaken for 5 minutes after the addition of calcium hydrogen and passed through the sieve, the weight-based content of particles having a maximum particle size of less than 1000 × 10 ⁻⁶ m was calculated.

[Production method]
[Example 1]
[Preparation of calcium dihydrogen phosphate]
Commercially available calcium dihydrogen phosphate raw material powder 200 × 10 ⁻³ kg (average particle size 999 × 10 ⁻⁶ m) was prepared, and a low-tap type sieve shaker (manufactured by Tokyo Glass Instruments Co., Ltd., S-1 type) and Using a sieve for JIS test (JIS Z8801) having a nominal aperture of 106 × 10 ⁻⁶ m, the powder passed through the sieve was used as the first powder.
The raw material powder prepared in the same manner as described above was pulverized for 90 minutes using a table-top ball mill (manufactured by Tokyo Glass Instruments Co., Ltd.), and a low-tap type sieve shaker and a sieve for nominal inspection of 106 × 10 ⁻⁶ m for JIS test (JIS Z8801) was used for sieving for 5 minutes, and the resulting powder on the sieve (average particle size 403 × 10 ⁻⁶ m) was used as the second powder.
The first powder and the second powder were mixed at a ratio of 10:90 on a weight basis to obtain a mixed calcium dihydrogen phosphate powder. The mixed calcium dihydrogen phosphate powder had an average particle size of 371 × 10 ⁻⁶ m, and the passing rate of a sieve having a nominal aperture of 1000 × 10 ⁻⁶ m was 98.2%.
[Production of molded body]
Mixed calcium dihydrogen phosphate powder 55.5 × 10 ⁻³ kg, calcium peroxide 9.7 × 10 ⁻³ kg, calcium carbonate 17.9 × 10 ⁻³ kg, calcium hydroxide 14.7 × 10 ⁻³ blended well and mixed so kg and ethylcellulose 0.5 × ¹⁰ -3 kg is contained, after obtaining the mixture, and mixed well again added ethyl alcohol 0.5 × ¹⁰ -3 kg, dried To obtain a mixture. The obtained mixture was put into a mold having a diameter of 13.2 × 10 ⁻³ m (bottom surface is circular) and press-molded (at a pressure of 25 MPa) using a rotary press molding machine (manufactured by Ebara Seiki). A molded body was produced. The obtained disk-shaped molded product had a diameter of 13.2 × 10 ⁻³ m and a thickness of 11.5 × 10 ⁻³ m. The compact density was 1.62 × 10 ³ kg / m ³ .

[Example 2]
The first powder and the second powder of Example 1 are mixed at a ratio of 15:85 on a weight basis, and have an average particle size of 353 × 10 ⁻⁶ m and a nominal aperture of 1000 × 10 ⁻⁶ m. A molded body was produced in the same manner as in Example 1, except that the mixed calcium dihydrogen phosphate powder had a pass rate of 98.3%.

[Example 3]
The first powder and the second powder of Example 1 are mixed at a ratio of 20:80 on a weight basis, and have an average particle size of 335 × 10 ⁻⁶ m and a nominal aperture of 1000 × 10 ⁻⁶ m. A molded body was produced in the same manner as in Example 1 except that the mixed calcium dihydrogen phosphate powder had a pass rate of 98.4%.

[Example 4]
The first powder and the second powder of Example 1 are mixed at a ratio of 30:70 on a weight basis, and have an average particle diameter of 300 × 10 ⁻⁶ m and a nominal aperture of 1000 × 10 ⁻⁶ m. A molded body was produced in the same manner as in Example 1, except that the mixed calcium dihydrogen phosphate powder had a pass rate of 98.7%.

[Example 5]
The first powder and the second powder of Example 1 are mixed at a ratio of 40:60 on a weight basis, and have an average particle diameter of 265 × 10 ⁻⁶ m and a nominal aperture of 1000 × 10 ⁻⁶ m. A molded body was produced in the same manner as in Example 1, except that the mixed calcium dihydrogen phosphate powder had a passage rate of 99.0%.

[Example 6]
A first powder was obtained in the same manner as in Example 1.
The raw material powder prepared in the same manner as in Example 1 was pulverized for 120 minutes using a ball mill, and a JIS test sieve (JIS Z8801) with a low tap type sieve shaker and a nominal aperture of 106 × 10 ⁻⁶ m was used. Sifting was performed for 5 minutes, and the obtained powder on the sieve (average particle size 261 × 10 ⁻⁶ m) was used as the second powder.
The first powder and the second powder are mixed at a ratio of 15:85 on a weight basis, and the average particle size is 232 × 10 ⁻⁶ m, and the sieve has a nominal aperture of 1000 × 10 ⁻⁶ m. Was a mixed calcium dihydrogen phosphate powder with 99.4%, and a molded body was produced in the same manner as in Example 1.

[Example 7]
The first powder and the second powder of Example 6 are mixed at a ratio of 30:70 on a weight basis, and have an average particle diameter of 201 × 10 ⁻⁶ m and a nominal aperture of 1000 × 10 ⁻⁶ m. A molded body was produced in the same manner as in Example 6 except that a mixed calcium dihydrogen phosphate powder having a pass rate of 99.5% was used.

[Example 8]
A first powder was obtained in the same manner as in Example 1.
The raw material powder prepared in the same manner as in Example 1 was pulverized for 60 minutes using a ball mill, and a low-tap type sieve shaker and a sieve for a JIS test having a nominal aperture of 106 × 10 ⁻⁶ m (JIS Z8801). Sifting was performed for 5 minutes, and the obtained powder on the sieve (average particle size 600 × 10 ⁻⁶ m) was used as the second powder.
The first powder and the second powder are mixed at a ratio of 15:85 on a weight basis, and the average particle size is 521 × 10 ⁻⁶ m, and the sieve has a nominal aperture of 1000 × 10 ⁻⁶ m. Was a mixed calcium dihydrogen phosphate powder with 97.1%, and a molded body was produced in the same manner as in Example 1.

[Example 9]
The first powder and the second powder of Example 8 are mixed at a ratio of 30:70 on a weight basis, and have an average particle size of 438 × 10 ⁻⁶ m and a nominal aperture of 1000 × 10 ⁻⁶ m. A molded body was produced in the same manner as in Example 8 except that the mixed calcium dihydrogen phosphate powder had a pass rate of 97.5%.

[Example 10]
A first powder was obtained in the same manner as in Example 1.
The raw material powder prepared in the same manner as in Example 1 was pulverized for 30 minutes using a ball mill, and using a low-tap sieve shaker and a sieve for JIS test (JIS Z8801) having a nominal aperture of 106 × 10 ⁻⁶ m. Sifting was performed for 5 minutes, and the obtained powder on the sieve (average particle diameter 797 × 10 ⁻⁶ m) was used as the second powder.
The first powder and the second powder are mixed at a ratio of 15:85 on a weight basis, and the passing rate of a sieve having an average particle diameter of 688 × 10 ⁻⁶ m and a nominal aperture of 1000 × 10 ⁻⁶ m. Was a mixed calcium dihydrogen phosphate powder of 95.8%, and a molded body was produced in the same manner as in Example 1.

[Example 11]
The first powder and the second powder of Example 10 are mixed in a ratio of 30:70 on a weight basis, and have an average particle size of 576 × 10 ⁻⁶ m and a nominal aperture of 1000 × 10 ⁻⁶ m. A molded body was produced in the same manner as in Example 10 except that the mixed calcium dihydrogen phosphate powder had a pass rate of 96.0%.

[Example 12]
A first powder was obtained in the same manner as in Example 1.
The raw material powder prepared in the same manner as in Example 1 was pulverized for 20 minutes using a ball mill, and using a low-tap type sieve shaker and a sieve for nominal opening 106 × 10 ⁻⁶ m for JIS test (JIS Z8801). Sifting was performed for 5 minutes, and the obtained powder on the sieve (average particle diameter 850 × 10 ⁻⁶ m) was used as the second powder.
The first powder and the second powder are mixed at a ratio of 10:90 on a weight basis, and the passing rate of a sieve having an average particle diameter of 773 × 10 ⁻⁶ m and a nominal aperture of 1000 × 10 ⁻⁶ m. Was a mixed calcium dihydrogen phosphate powder of 92.0%, and a molded body was produced in the same manner as in Example 1.

[Comparative Example 1]
A first powder was obtained in the same manner as in Example 1.
The raw material powder prepared in the same manner as in Example 1 was pulverized for 180 minutes using a ball mill, and a JIS test sieve (JIS Z8801) with a low tap type sieve shaker and a nominal mesh size of 106 × 10 ⁻⁶ m was used. Sifting was performed for 5 minutes, and the obtained powder on the sieve (average particle size 110 × 10 ⁻⁶ m) was used as the second powder.
The first powder and the second powder are mixed at a ratio of 5:95 on a weight basis, the average particle diameter is 108 × 10 ⁻⁶ m, and the passing rate of a sieve having a nominal aperture of 1000 × 10 ⁻⁶ m. Was a mixed calcium dihydrogen phosphate powder of 99.7%, and a molded body was produced in the same manner as in Example 1.

[Comparative Example 2]
The first powder and the second powder of Comparative Example 1 are mixed at a ratio of 45:55 on a weight basis, and have an average particle diameter of 89 × 10 ⁻⁶ m and a nominal aperture of 1000 × 10 ⁻⁶ m. A molded body was produced in the same manner as in Comparative Example 1 except that the mixed calcium dihydrogen phosphate powder had a 99.9% pass rate.

[Comparative Example 3]
The first powder and the second powder of Comparative Example 1 are mixed at a ratio of 15:85 on a weight basis, and have an average particle size of 107 × 10 ⁻⁶ m and a nominal aperture of 1000 × 10 ⁻⁶ m. A molded body was produced in the same manner as in Comparative Example 1 except that a mixed calcium dihydrogen phosphate powder having a pass rate of 99.8% was used.

[Comparative Example 4]
A first powder was obtained in the same manner as in Example 1.
The raw material powder prepared in the same manner as in Example 1 was pulverized for 10 minutes using a ball mill, and using a low-tap type sieve shaker and a sieve for nominal inspection of 106 × 10 ⁻⁶ m for JIS test (JIS Z8801). Sifting was performed for 5 minutes, and the resulting powder on the sieve (average particle size 950 × 10 ⁻⁶ m) was used as the second powder.
The first powder and the second powder are mixed at a ratio of 5:95 on a weight basis, the average particle diameter is 908 × 10 ⁻⁶ m, and the sieve has a nominal aperture of 1000 × 10 ⁻⁶ m. Was 88.0% of mixed calcium dihydrogen phosphate powder, and a molded body was produced in the same manner as in Example 1.

[Comparative Example 5]
The first powder and the second powder of Comparative Example 4 are mixed at a ratio of 45:55 on a weight basis, and have an average particle diameter of 540 × 10 ⁻⁶ m and a nominal aperture of 1000 × 10 ⁻⁶ m. A compact was produced in the same manner as in Comparative Example 4 except that the mixed calcium dihydrogen phosphate powder had a 97.0% pass rate.

[Comparative Example 6]
The first powder and the second powder of Comparative Example 4 are mixed at a ratio of 15:85 on a weight basis, and have an average particle diameter of 810 × 10 ⁻⁶ m and a nominal aperture of 1000 × 10 ⁻⁶ m. A molded body was produced in the same manner as in Comparative Example 4 except that a mixed calcium dihydrogen phosphate powder having a pass rate of 90.0% was used.

[Comparative Example 7]
A first powder was obtained in the same manner as in Example 1.
The raw material powder prepared in the same manner as in Example 1 was pulverized for 60 minutes using a ball mill, and a low-tap type sieve shaker and a sieve for a JIS test having a nominal aperture of 106 × 10 ⁻⁶ m (JIS Z8801). Sifting was performed for 5 minutes, and the obtained powder on the sieve (average particle size 600 × 10 ⁻⁶ m) was used as the second powder.
The first powder and the second powder are mixed at a ratio of 5:95 on a weight basis, and have a mean particle diameter of 569 × 10 ⁻⁶ m and a passing rate of a sieve having a nominal aperture of 1000 × 10 ⁻⁶ m. Was a mixed calcium dihydrogen phosphate powder of 96.5%, and a molded body was produced in the same manner as in Example 1.

[Comparative Example 8]
The first powder and the second powder of Comparative Example 7 are mixed at a ratio of 45:55 on a weight basis, and have an average particle diameter of 359 × 10 ⁻⁶ m and a nominal aperture of 1000 × 10 ⁻⁶ m. A molded body was produced in the same manner as in Comparative Example 7 except that a mixed calcium dihydrogen phosphate powder having a pass rate of 98.2% was used.

[Comparative Example 9]
A first powder was obtained in the same manner as in Example 1.
The raw material powder prepared in the same manner as in Example 1 was pulverized for 90 minutes using a ball mill, and a JIS test sieve (JIS Z8801) with a low-tap type sieve shaker and a nominal aperture of 106 × 10 ⁻⁶ m was used. Sifting was performed for 5 minutes, and the obtained powder on the sieve (average particle size 403 × 10 ⁻⁶ m) was used as the second powder.
The first powder and the second powder are mixed at a ratio of 5:95 on a weight basis, and the average particle diameter is 391 × 10 ⁻⁶ m, and the sieve has a nominal aperture of 1000 × 10 ⁻⁶ m. Was a mixed calcium dihydrogen phosphate powder of 98.0%, and a molded body was produced in the same manner as in Example 1.

[Comparative Example 10]
The first powder and the second powder of Comparative Example 9 are mixed at a ratio of 45:55 on a weight basis, and have an average particle diameter of 250 × 10 ⁻⁶ m and a nominal aperture of 1000 × 10 ⁻⁶ m. A molded body was produced in the same manner as in Comparative Example 9 except that the mixed calcium dihydrogen phosphate powder had a 99.2% pass rate.

  Tables 1 and 2 show the evaluation results regarding the molded bodies obtained in the above Examples and Comparative Examples, respectively.

  The oxygen generating compositions of the examples all showed a good oxygen release amount without causing a sudden change in water quality.

  The oxygen generating composition of the present invention and the oxygen generating composition obtained by the production method of the present invention are used in water, and are useful for maintaining a culture environment for aquatic organisms such as ornamental fish. Specifically, a sufficient amount of oxygen can be released and stable even in small amounts of calcium peroxide in aquarium water such as aquarium for appreciation fish, fish tanks, and fish tanks for transporting live fish. It is useful for maintaining a typical water quality environment. It is particularly useful for maintaining an environment suitable for breeding ornamental fish such as medaka and freshwater shrimp that dislike water quality changes and transporting live fish.

Claims (6)

An oxygen generating composition comprising a molded body containing 2 to 20% calcium peroxide, 2 to 30% calcium carbonate, 2 to 30% calcium hydroxide, and 30 to 80% calcium dihydrogen phosphate, Calcium hydride is a particle having an average particle diameter of 150 × 10 ^{−6 to} 800 × 10 ⁻⁶ m, and calcium dihydrogen phosphate particles having a maximum particle diameter of less than 106 × 10 ⁻⁶ m are based on the weight of calcium dihydrogen phosphate. An oxygen generating composition characterized by containing in a range of 10 to 40%. The calcium dihydrogen phosphate contains 95% or more of calcium dihydrogen phosphate particles having a maximum particle diameter of less than 1000 × 10 ⁻⁶ m based on the weight of calcium dihydrogen phosphate. Oxygen generating composition. The calcium dihydrogen phosphate is a calcium dihydrogen phosphate particle having a maximum particle size of less than 106 × 10 ⁻⁶ m and a minimum particle size of 106 × 10 ⁻⁶ m or more and an average particle size of 200 × 10 ⁻⁶ to 3. The oxygen generating composition according to claim 1, comprising 800 × 10 ⁻⁶ m calcium dihydrogen phosphate particles in a ratio of 10:90 to 40:60 on a weight basis. A method for producing an oxygen generating composition comprising:
10 to 40% of calcium dihydrogen phosphate particles having an average particle diameter of 150 × 10 ^{−6 to} 800 × 10 ⁻⁶ m and a maximum particle diameter of less than 106 × 10 ⁻⁶ m based on the weight of calcium dihydrogen phosphate. Preparatory step for preparing calcium dihydrogen phosphate containing range (A)
Calcium peroxide 2 to 20% by weight, calcium carbonate 2 to 30% by weight, calcium hydroxide 2 to 30% by weight, and calcium dihydrogen phosphate 30 to 80% by weight obtained in the preparation step (A) are mixed. Then, a mixing step (B) for obtaining a mixture, and a molding step (C) for molding the mixture obtained in the mixing step to obtain an oxygen generating composition comprising a molded body
A method for producing an oxygen generating composition comprising: The preparation step (A)
i) Step of preparing calcium dihydrogen phosphate particles having a maximum particle size of less than 106 × 10 ⁻⁶ m as a first powder ii) The minimum particle size is 106 × 10 ⁻⁶ m or more and the average particle size is 200 × 10 ⁻ A step of preparing ^{6 to} 800 × 10 ⁻⁶ m of calcium dihydrogen phosphate particles as a second powder, and iii) the first powder and the second powder on a weight basis of 10:90 to 40:60. The manufacturing method of the oxygen generating composition of Claim 4 including the process mixed in the ratio of these. The calcium dihydrogen phosphate obtained in the preparation step (A) contains 95% or more of calcium dihydrogen phosphate particles having a maximum particle diameter of less than 1000 × 10 ⁻⁶ m based on the weight of calcium dihydrogen phosphate. The method for producing an oxygen generating composition according to claim 4 or 5.