JP5026630B2 - Granulated powder, method for producing the same and compression molded solid - Google Patents

Description

【００７０】
【表２】

【００７１】
【表３】

【００７２】
【表４】

【００７３】
【表５】

【００７４】
【発明の効果】
以上説明したように、本発明によれば、粉体と、コーティング剤とをコーティング剤の融点未満の温度で加熱混合することにより、実質的に問題となるような凝集体を形成することなく、粉体の各粒子表面がコーティング剤による被膜で被覆された造粒粉体を得ることができる。その結果、被膜形成効率及び収率が高くなり、再現性もよく、また、温度コントロ−ルも容易となって、連続生産が可能となる。
【００７５】
さらに、混合温度が低いため、消費熱量が小さく、また粒子固化のための冷却に要する時間やエネルギ−が少ないか若しくは必要でなくなり、安価に被膜形成できる。
【００７６】
また、得られた造粒粉体は、粒子同士の凝集がほとんど見られず、粒子表面全体がコーティング剤により均一に被覆された状態となっていることから、圧縮成形用として好適な原料となる。
【００７７】
また、上記造粒粉体を原料として圧縮成形して得られた圧縮成形固形物は、強度が高く、かつ長期保存性に優れるという効果を奏する。
【図面の簡単な説明】
【図１】 図１は、走査型電子顕微鏡写真の模写図であり、（Ａ）はクエン酸粒子を、（Ｂ）はＰＥＧ膜被覆クエン酸粒子を、（Ｃ）は重炭酸ナトリウムが付着したＰＥＧ膜被覆クエン酸粒子をそれぞれ示す。
【図２】 図２は、本発明の被膜形成方法の実施に用いる混合装置の内部構造を示す。
【図３】 図３は、ＰＥＧ膜被覆粒子を固化するための流動層乾燥装置の概略を示す。
【符号の説明】
１・・・ 混合容器、２・・・ メインブレ−ド、
３・・・ クロススクリュ−、４・・・ 混合容器蓋部、
５・・・ 排出孔、６・・・ 点検窓、７・・・ 排気部、
１１・・・ 空気流、１２・・・ 粒子[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a granulated powder in which a film of a coating agent is formed on the particle surface of the powder and a method for producing the same, and to a compression molded solid using the granulated powder as a raw material. In particular, in the production of organic acid particles coated with a nonionic surfactant such as polyethylene glycol (hereinafter referred to as PEG), a method for producing a granulated powder with which a desired product can be obtained with good yield and reproducibility. It is about.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, there are known cleaning agents, bathing agents, and the like in which organic acid particle surfaces are coated with PEG and this PEG is compression molded using a binder of an organic acid and sodium carbonate or sodium bicarbonate. These detergents and bathing agents prevent contact between organic acids and sodium bicarbonate, etc., and allow them to be stored in the presence of them, while when used in water, the components react to generate carbon dioxide. However, since it dissolves quickly, it has the effect of improving the cleaning effect and giving the consumer a comfortable feeling of use.
[0003]
As a method for producing the foamable cleaning agent, etc., a powder composed of an organic acid and PEG are heated and melt mixed at 60 ° C. to 100 ° C., and then cooled and powdered to obtain PEG-coated organic acid particles. There is known a method (Japanese Patent Publication No. 2-10126) in which sodium bicarbonate, sodium carbonate, and the like are added to the product and compression molded.
[0004]
[Problems to be solved by the invention]
However, in the above production method, the organic acid and PEG are heated to a temperature higher than the melting point of PEG (60 to 100 ° C.) and mixed in the mixing container. A large amount adheres in a highly viscous state containing organic acids.
[0005]
As a result, the formation efficiency of the PEG film on the particle surface of the organic acid is poor, the reproducibility of the production yield is poor, the heat consumption is large due to the high mixing temperature, and time and energy are required for cooling, etc. There were difficulties.
[0006]
In addition, since the processed organic acid particles are bonded to each other by molten PEG to form a lump aggregate, when used as a raw material for a compression-molded solid, a step of powdering the aggregate is necessary. In addition, a part of the surface of the organic acid particles is exposed in the step of powdering the agglomerates, resulting in a difficulty in affecting the long-term stability as a compression molded solid.
[0007]
Therefore, in the present invention, a coating agent film such as PEG is formed on the particle surface of the powder composed of citric acid and the like, and a granulated powder excellent in long-term stability and a method for producing the same are provided. An object of the present invention is to provide a compression-molded solid material having excellent characteristics using a powder.
[0008]
[Means for Solving the Problems]
As a result of diligent research to achieve this object, PEG and organic acids or salts thereof (hereinafter referred to as “organic”) have been thought to be uncoated unless heated and melted to a temperature higher than the melting point. It is found that a PEG film is formed on the particle surface of an organic acid or the like even if the heating temperature is lower than the melting point of PEG if the particles comprising the acid or the like are sufficiently mixed. It came to complete.
[0009]
That is, the granulated powder according to the present invention comprises a powder comprising an organic acid or a salt thereof and a solid coating agent having a melting point lower than that of the powder, 5% to 50% lower than the melting point of the coating agent. heating It is characterized in that it is heated and mixed at a temperature to form a coating agent film on the particle surface of the powder.
[0010]
If comprised as mentioned above, although the heating temperature is the temperature below melting | fusing point of a coating agent, the granulated powder by which the coating agent film was formed on the particle | grain surface of a powder will be obtained. When an organic acid such as citric acid is used as the powder and PEG is used as the coating agent, the state of the film formation is observed. Under conditions where the heating temperature is lower than the melting point of PEG, citric acid particles The PEG is selectively melted only at the portion in contact with the substrate and a PEG film is formed on the particle surface, but the PEG does not melt at the portion not in contact with the particle.
[0011]
Further, it has been clarified that even if the particles once formed with the PEG coating are in contact with each other, since the temperature is lower than the melting point, the viscosity of PEG is low and aggregates are not easily formed.
[0012]
Although the above mechanism is unknown, it is completely different from the state where PEG is totally melted by heating above the melting point. To distinguish from this state, only the coating agent in contact with the powder particles is used. In the present specification, a state where the smelting is melted is referred to as a “selectively melted” state.
[0013]
The “selectively melted” state is considered to be manifested when a powder having excellent stability (thermal stability, crystal structural stability, etc.) is used. When inferior sodium bicarbonate or sodium sulfate that is structurally brittle under dry conditions is used as a powder, PEG does not melt.
[0014]
In addition, when organic acid or the like is used as a powder and sodium bicarbonate or sodium sulfate is mixed therewith, selective melting of PEG occurs on the particle surface of the organic acid or the like, but sodium bicarbonate or sodium sulfate. No melting of PEG occurs on the particle surface. If mixing is continued as it is, a film of PEG is finally formed on the surface of particles of organic acid or the like, and particles having a structure in which sodium bicarbonate or sodium sulfate adheres on the film are formed. That is, an organic acid or the like and sodium bicarbonate or sodium sulfate are not in direct contact with each other, and a granulated powder having excellent long-term storage stability can be obtained.
[0015]
As described above, according to the present invention, the viscosity of the coating agent is smaller than in the conventional case of coating at a high temperature above the melting point, and the contents (powder and coating agent) adhere to the inner wall of the mixing container. The amount is drastically reduced, with little or no deposits.
[0016]
Therefore, the coating efficiency of the coating agent and the yield of the product are increased, the reproducibility is good, and there is almost no deposit on the inner wall of the container, so that the temperature control is facilitated and continuous production is possible. Furthermore, since the mixing temperature is low, the amount of heat consumed is small, and the time and energy required for cooling to stabilize the coating are little or unnecessary, and the coating can be formed at low cost.
[0017]
Here, the temperature at “the heating temperature is less than the melting point of the coating agent” refers to a temperature measured by bringing a temperature sensor directly into contact with the contents charged in the mixing apparatus. That is, not only the temperature of the mixing apparatus is not higher than the melting point of the coating agent, but also the temperature of the contents is required to be lower than the melting point of the coating agent even when the frictional heat generated by mixing is taken into account. The temperature for heating the contents is preferably 5% to 50% lower than the melting point of the coating agent.
[0018]
The powder means an aggregate of powdery or granular particles, and as described above, organic acids such as citric acid, malic acid, succinic acid, fumaric acid, tartaric acid, and salts thereof having excellent stability are preferably used. Can be used. The shape of the powder particles is not particularly limited, and may be spherical or flake as well as amorphous particles.
[0019]
Further, in this specification, “granulated powder” means that a coating film is formed on the surface of each particle constituting the powder, and does not substantially contain aggregates that cause problems during compression molding. It means a powder, which is different from the conventional surface-coated powder in which an agglomerate is inevitably produced because the organic acid and PEG are mixed by heating to the melting point of PEG or higher. .
[0020]
The size of the powder particles includes powder to granular materials, but usually 1 to 1000 μm. Among them, it is preferable to use those having a thickness of 100 to 700 μm, and it is more preferable to use those having a thickness of 300 to 500 μm. If the particle size is less than 1 μm, the PEG-coated particles tend to agglomerate. If the particle size exceeds 1000 μm, the particles are pulverized by shearing force due to mixing, and the yield of the desired particle size is reduced. This is because it tends to occur and thereby partly aggregates. In addition, a powder may be used individually by 1 type and it is also possible to use 2 or more types together.
[0021]
The coating agent is not particularly limited as long as it is solid at room temperature and can be melted by heating. For example, solid wax or the like can be used.
[0022]
As described above, when used as a raw material for a drug dissolved in water such as a cleaning agent or a bathing agent, it is represented by, for example, PEG, polyoxyethylene alkyl ether, and polyoxyethylene polyoxypropylene block polymer. A water-soluble material such as a nonionic surfactant may be used as the coating agent.
[0023]
Among them, PEG is preferable in that it has abundant grades and is excellent in solubility in water. Particularly, those having an average molecular weight of 2000 to 20000 can form a film in a preferable temperature range of 35 ° C. to 55 ° C. The effects such as efficiency, reproducibility of yield, continuous production, and low cost can be achieved more reliably and more effectively. In addition, a coating agent may be used individually by 1 type and can also be used together 2 or more types.
[0024]
The shape of the coating agent is not particularly limited, and various shapes such as a granular shape, a block shape, and a flake shape can be used. In addition, since the amount of coating agent used varies depending on the specific surface area of the powder and the like, it may be appropriately adjusted according to the powder actually used. By blending -100 parts by weight, preferably 3-50 parts by weight, more preferably 5-20 parts by weight, a substantially uniform coating film of the coating agent can be formed on the particle surface of the powder.
[0025]
When mixing the powder and the coating agent, the powder may be put in the mixing device in advance, and the PEG may be blended while mixing the powder or while the mixing is interrupted. The body and PEG can be added and mixed at the same time, but the latter has a certain amount of PEG from the beginning together with the citric acid particles, so the coating thickness is more uniform by adjusting the mixing speed Tend to be.
[0026]
The means for mixing the powder and the coating agent can be used without any particular limitation. For example, a stirring mixer such as a vertical granulator or a Henschel mixer or a kneader such as a kneader is used. be able to.
[0027]
The granulated powder having a film formed as described above is cooled while being mixed in a mixing apparatus or a fluidized bed dryer, and then taken out. The obtained granulated powder is hardly aggregated between particles, and the entire surface is uniformly coated with a coating agent, so that it can be used as a raw material for compression molding solids such as molding agents. It can be preferably used.
[0028]
That is, in order to exhibit sufficient strength and function as a compression-molded solid, it is necessary that the components in the solid are uniform, but the powder obtained by the conventional manufacturing method is in a lump shape. In order to form the agglomerates, a step of powdering the agglomerates is required, and a part of the powder is exposed by the powdering step, so that the storage stability as a compression-molded solid has been a problem. On the other hand, the surface-coated powder according to the present invention does not substantially generate an agglomerate that is a problem as a raw material for compression molding, and the entire particle surface is uniformly coated with a coating agent. It can be suitably used as a raw material for use.
[0029]
The granulated powder is compression-molded alone or mixed with other compounding agents as necessary. For example, when used as a foaming cleaning agent, bathing agent, bath water cleaning agent or pool disinfectant as described above, as a compounding agent, carbonates such as sodium carbonate, bicarbonates such as sodium bicarbonate, etc. In addition to salt and other substances such as fragrances, pigments, surfactants, mirabilite, sodium sesquicarbonate, various bound phosphates, inorganic salts such as sodium chloride, hydrogen peroxide such as perborate, percarbonate, persulfate Adducts, bactericides, anti-inflammatory agents, pharmaceutical extracts, cellulose derivatives, carbohydrates such as starch, and the like can be used.
[0030]
In addition, these compounding agents may be applied to the film forming step together with the powder, or may be added after the film forming step. In any case, as described above, since the coating agent is selectively melted on the particle surface of the powder to form a film, the compounding agent is finally added on the film formed on the particle surface. A powder having an attached particle structure is obtained.
[0031]
Furthermore, if the amount of the coating agent and the heating and mixing conditions (mixing time, heating temperature, etc.) are appropriately adjusted, it is possible to obtain a powder having a particle structure in which even the compounding agent is coated with the coating agent. Therefore, as a compounding agent, a highly volatile product such as a fragrance, a disinfectant, a deodorant, an antiseptic, an insect repellent and a repellent, a product having poor stability in air, specifically menthol and menthol derivatives Or long-term storage such as lactic acid menthyl becomes possible.
[0032]
Further, if at least a part of the compounding agent is blended as a cooling substance after completion of the film forming step, the formed film can be stabilized by lowering the product temperature of the powder. It is possible to effectively prevent the agglomeration.
[0033]
The cooling substance is not particularly limited as long as it can lower the temperature of the coating film formed on the particle surface of the powder when added, but it is preferable to use a substance having a large specific heat in order to enhance the cooling effect. Furthermore, in order to obtain a uniform cooling effect as a whole, it is preferable to use a powdery or granular material. As such a cooling substance, inorganic salts such as carbonates and mirabilite are particularly preferably used among the above compounding agents.
[0034]
Furthermore, since the powdery or granular cooling substance acts in the same manner as the dusting at the time of noodle making, the surface-coated particles are reattached by their own weight when taken out from the mixing device after the coating is formed. It is possible to prevent the cooling time in the mixing apparatus.
[0035]
In the present invention, there are many advantages when blending other compounding agents. For example, when blending a fragrance, the mixing temperature is low, so loss due to volatilization can be suppressed. Since the difference between the conventional mixing temperature and the mixing temperature in the present invention is large, the loss suppressing effect of such a volatile compounding agent is high.
[0036]
As described above, the granulated powder obtained by the present invention does not substantially generate an agglomerate which is a problem as a raw material for compression molding, and the entire particle surface is uniformly coated with a coating agent. Therefore, the compression molded solid obtained by compression molding using this as a raw material has the effect of high strength and excellent long-term storage stability.
[0037]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described. However, the present invention is not limited to the film forming method shown in this embodiment and the method for producing a compression-molded solid using particles produced by this method. .
[0038]
In this embodiment, citric acid having a particle size of 100 to 700 μm is used as the powder, and PEG (melting point: 55 to 60 ° C.) 3 having an average molecular weight of 4000 to 10,000 as a coating agent with respect to 100 parts by weight of citric acid. ˜50 parts by weight in a mixing vessel of a stirring and mixing device, and mixed at a temperature lower than the melting point of PEG (35 to 55 ° C.), whereby a granulated powder having a PEG film formed on the particle surface of citric acid powder The body is obtained.
[0039]
In this case, the mixing may be performed after the entire amount of citric acid particles and PEG is charged into the mixing container, or firstly mixed after the citric acid particles are charged, and then the PEG is charged while mixing or while mixing is interrupted. Further, mixing may be continued. Next, when sodium carbonate, sodium bicarbonate, or the like is added according to the purpose, a granulated powder having a structure in which these are attached to the citric acid particles via the PEG coating is obtained.
[0040]
In addition, since the heating temperature is lower than the melting point of PEG and the mixture is stirred and mixed at a low temperature of 35 ° C. to 55 ° C., the stickiness of PEG after film formation is small, and the contents on the inner wall of the container are almost not added even when sodium carbonate or the like is added. Does not adhere. Therefore, almost all of the contents can be granulated without agglomeration, and granulated powder can be produced efficiently, and continuous production is possible if the produced granulated powder is discharged from the container and then the raw materials are charged continuously. It becomes.
[0041]
Moreover, sodium carbonate, sodium bicarbonate, etc. are mentioned as the cooling substance added at the end. Since these have the effect | action which cools granulated powder, the stable granulated powder of the shape which does not reattach after discharge | emission from a container can be manufactured by adding these. In addition, when this granulated powder is poured into water, citric acid and sodium bicarbonate react with each other to quickly dissolve while generating carbon dioxide gas, so that it can be used for foaming detergents, bathing agents, etc. .
[0042]
If the above granulated powder (citric acid particles coated only with PEG film or those with sodium carbonate etc. attached thereto) is tableted using a tableting machine, a compression-molded solid with a predetermined shape is easy. Can be manufactured.
[0043]
【Example】
EXAMPLES Hereinafter, although this invention is demonstrated further more concretely using an Example, this invention is not limited to these Examples.
[0044]
[Example 1]
FIG. 2 is a diagram showing an internal structure of the stirring and mixing apparatus (FM-VG-25 type manufactured by Paulec Co., Ltd.) used in this example. This stirring and mixing device includes a main blade 2 that rotates horizontally at the bottom of a cylindrical mixing container 1 and a cross screw 3 that rotates at high speed in the vertical direction at the top of the side wall of the container. The powder is given a centrifugal force and a rotational force by the main blade 2, and rises along the wall surface of the container 1 and falls toward the center, thereby rotating in the container 1 while repeating rolling and compaction movements. However, a shearing force is locally applied so that the cross screw 3 shears vertically during the rolling.
[0045]
When 4 kg of citric acid (average particle size: 500 μm) is introduced into the mixing container 1 (internal volume; 25 liters) as a first stage and mixed with the main blade 2 and the cross screw 3, the contents are as shown in Table 1. The temperature of the product gradually rises, and after 5.5 minutes, the temperature of the contents approaches the jacket temperature, and mixing is stopped at this point.
[0046]
Here, as a second stage, when 0.6 kg of PEG (average molecular weight: 6000, melting point: 58-60 ° C.) is charged and mixing is resumed, PEG starts to selectively melt, and all of PEG selectively melts. After mixing (1 minute after resuming mixing), when the temperature rises and becomes substantially equal to the jacket temperature (4.5 minutes after resuming mixing), mixing is stopped and a part of the product is taken out. Here, as a third stage, 4 kg of sodium bicarbonate was added to resume mixing, and when the temperature drop became substantially constant (1.5 minutes after resuming mixing), the discharge hole 5 was opened and the resulting structure was obtained. Remove the granular powder.
[0047]
The operating conditions of the device are as follows.
Jacket set temperature: 50 ° C,
Rotation speed of main blade 2; 180 rpm,
Rotational speed of the cross screw 3; 1800 rpm,
Measuring the temperature of the contents; Measuring the temperature sensor in contact with the contents.
[0048]
In the case of this example, despite the use of PEG having a melting point of 58-60 ° C., all PEG is selectively melted at a temperature of about 45 ° C. to coat the citric acid particles. FIG. 1 is a copy of a scanning electron micrograph, wherein (A) shows citric acid particles, (B) shows PEG film-coated citric acid particles after completion of the second stage, and (C) shows after completion of the third stage. Of sodium bicarbonate attached PEG film coated citric acid particles. In the stage (A), many irregularities are observed on the surface of the citric acid particles, but in the stage (B), the surface becomes smooth and it can be seen that the citric acid particles are covered with the PEG film. Furthermore, many particles of deposits are observed in the stage (C), which indicates that fine particles of sodium bicarbonate are attached to the citric acid particles through the PEG film. In this example, the adhesion of the contents to the inner wall of the mixing container was hardly observed, and a granulated powder was obtained with a high yield (99% or more).
[0049]
Since the PEG film-coated citric acid particles after completion of the second stage may be taken out in a heated state and left to stand, the particles may adhere to each other and partially agglomerate. For example, using a fluidized bed dryer as shown in FIG. When the particles 12 are blown up with the air stream 11 and cooled while being separated, the PEG film on the particle surfaces is solidified, and a granulated powder having a stable shape and substantially free from aggregation is obtained.
[0050]
[Example 2]
In a mixing container 1 (internal volume: 40 liters) of the apparatus shown in FIG. 2 (FM-VG-25, manufactured by Paulec Co., Ltd.), 5 kg of citric acid (average particle diameter: 500 μm) and sodium bicarbonate ( 4 kg) (average particle size: 100 μm) and mixed with the main blade 2 and the cross screw 3, the contents gradually increased in temperature as shown in Table 2, and 7 minutes after the addition, the temperature of the contents And jacket temperature are almost equal.
[0051]
At this point, mixing is stopped, and as a second stage, when 0.75 kg of PEG (average molecular weight: 6000, melting point: 58-60 ° C.) is charged and mixing is resumed, PEG begins to selectively melt, Since the temperature drop is almost constant at the time of melting (1.25 minutes after resuming mixing), the mixing is stopped at this point, and 1.5 kg of sodium bicarbonate is added as the third stage to mix. When the temperature dropped and the temperature drop became substantially constant (1.25 minutes after resuming mixing), the discharge hole 5 was opened and the resulting granulated powder was taken out.
[0052]
The operating conditions of the device are as follows.
Jacket set temperature: 48 ℃
Rotation speed of main blade 2; 180 rpm,
Rotational speed of the cross screw 3; 1800 rpm,
Measuring the temperature of the contents; Measuring the temperature sensor in contact with the contents.
[0053]
The particles after completion of the third stage obtained in this example are in the surface state shown in FIG. 1C, and fine particles of sodium bicarbonate are attached to the citric acid particles via the PEG film. . Also in this example, the adhesion of the contents to the inner wall of the mixing container was hardly observed, and a granulated powder was obtained with a high yield (99% or more).
[0054]
[Example 3]
In a mixing vessel (internal volume; 100 liters) of an apparatus (FM-VG-100P type manufactured by Paulec Co., Ltd.) having a volume different from those of Examples 1 and 2, 25 kg of citric acid (average particle size: 500 μm) is used as a first step. And 20 kg of sodium bicarbonate (average particle size: 100 μm) are mixed with the main blade 2 and the cross screw 3, the contents gradually rise in temperature as shown in Table 3, and the temperature of the contents is changed to the jacket. Mixing is stopped when the temperature is exceeded (5.66 minutes after charging).
[0055]
As a second step, when 3.75 kg of PEG (average molecular weight: 6000, melting point: 58-60 ° C.) was added and mixing was resumed, the PEG began to selectively melt and the temperature of the contents decreased, Since the temperature drop is almost constant at the point of time when it is selectively melted (1 minute after resuming mixing), the mixing is stopped at this point, and 7.5 kg of sodium bicarbonate is added and mixed as the third stage. Was restarted, and when the temperature drop became substantially constant (0.75 minutes after resuming mixing), the discharge holes 5 were opened, and the resulting granulated powder was taken out.
[0056]
The operating conditions of the device are as follows.
Jacket set temperature: 43 ° C,
Rotation speed of main blade 2; 140 rpm,
Rotational speed of the cross screw 3; 1800 rpm,
Measuring the temperature of the contents; Measuring the temperature sensor in contact with the contents.
[0057]
In the present embodiment, the scale is set to four times that of the second embodiment, the set temperature of the jacket is lowered, and the rotational speed of the main blade 2 is lowered so that the peripheral tip speed of the blades of the blades of the blades is reduced. It is the same as the thing.
[0058]
In this case, in the state where the set temperature of the jacket was lowered by 5 ° C. from Example 2, after about 5 minutes from the start of mixing, the temperature of the contents exceeded the temperature of the jacket. PEG selectively melted in a state where the temperature of the contents was lower than in Example 2, and the particles obtained after the completion of the third stage were in the surface state shown in FIG.
[0059]
This is because, according to the present invention, even when the scale is considerably increased and the mixing temperature is set to be considerably lower than the melting point, sodium bicarbonate adheres to the PEG film formed on the surface of the citric acid particles. It shows that a granulated powder having the above structure can be obtained with good reproducibility. In Example 3, the adhesion of the contents to the inner wall of the mixing container was hardly observed, and a granulated powder was obtained with a high yield (99% or more).
[0060]
[Example 4]
In this example, various organic acids or salts thereof, sodium sulfate, and sodium bicarbonate were used as powders, and the coating state of PEG on the particle surface was examined. Specifically, first, a mixing container (internal volume; 5 liters) of an apparatus (FM-VG-05 type manufactured by Paulec Co., Ltd.) having a capacity different from that of Example 1 is heated to each set temperature in advance. Thereto, 1.0 kg of powder is charged and mixing is continued until the temperature of the contents reaches a set temperature.
[0061]
The operating conditions for the apparatus are as follows.
Set temperature: Tests performed at 5 ° C intervals from 30 to 55 ° C
Rotation speed of main blade 2; 500 rpm
Rotational speed of cross screw 3; 1800 rpm
[0062]
Next, as the second stage, mixing was once stopped, and PEG (average molecular weight; 6000, melting point; 58 to 60 ° C.) was added in the amount shown in Table 4 to resume mixing. Whether or not the particles were selectively melted on the particle surface was observed and evaluated according to the following criteria.
(Criteria)
○ ... melts immediately (melts within 1 minute)
Δ: Melting takes time (melting takes more than 1 minute)
X: not melted (mixed for 3 minutes and not melted)
[0063]
As shown in Table 4, when organic acids and organic acid salts were used as powders, PEG was rapidly and selectively melted under heating conditions of 40 ° C. and could be coated on the particle surface. On the other hand, it was confirmed that when mirabilite and baking soda were used as the powder, PEG did not melt and was not coated even under heating conditions of 55 ° C.
[0064]
[Example 5]
In this example, the coating state of the powder on the particle surface when a pluronic-type nonionic surfactant (melting point: 60 to 65 ° C.) was used as the coating agent was examined. Specifically, the test was performed under the same test conditions as in Example 4 except that 1.0 kg of citric acid was used as the powder and the above pluronic type nonionic surfactant was used as the coating agent.
[0065]
As a result, as shown in Table 5, it was confirmed that the pluronic-type nonionic surfactant was selectively melted on the surface of the citric acid particle under the heating condition of 45 ° C. and could be coated on the particle surface. It was.
[0066]
[Comparative example]
The test was carried out under the same operating conditions as in Example 1 except that the set temperature of the jacket was 70 ° C. Specifically, as the first stage, 4 kg of citric acid is charged into the mixing container, and mixing is once stopped when the temperature of the contents approaches 70 ° C.
[0067]
As the second stage, 0.6 kg of PEG was added and mixing was resumed. Mixing was stopped in 4.5 minutes from the restart, and as the third stage, 4 kg of sodium bicarbonate was added and mixed for 1.5 minutes. The discharge hole 5 was opened and the contents were taken out.
[0068]
In this comparative example, a large amount of contents adhered to the inner wall of the mixing container, and the yield was as low as 70%. Moreover, since the taken-out contents were agglomerated by aggregation of powders, they were pulverized with a rotary granulator. When the obtained powder was observed with an electron microscope, it was confirmed that portions where citric acid was exposed were scattered.
[0069]
[Table 1]

[0070]
[Table 2]

[0071]
[Table 3]

[0072]
[Table 4]

[0073]
[Table 5]

[0074]
【Effect of the invention】
As described above, according to the present invention, by heating and mixing the powder and the coating agent at a temperature lower than the melting point of the coating agent, without forming an aggregate that is substantially problematic, A granulated powder in which the surface of each particle of the powder is coated with a coating with a coating agent can be obtained. As a result, film formation efficiency and yield are increased, reproducibility is good, temperature control is facilitated, and continuous production is possible.
[0075]
Furthermore, since the mixing temperature is low, the amount of heat consumed is small, and the time and energy required for cooling for solidifying the particles are little or unnecessary, and a coating can be formed at low cost.
[0076]
Further, the obtained granulated powder hardly aggregates between the particles, and the entire particle surface is uniformly coated with the coating agent, so that it is a suitable raw material for compression molding. .
[0077]
In addition, a compression molded solid obtained by compression molding using the granulated powder as a raw material has an effect of high strength and excellent long-term storage stability.
[Brief description of the drawings]
FIG. 1 is a copy of a scanning electron micrograph showing (A) citric acid particles, (B) PEG film-coated citric acid particles, and (C) sodium bicarbonate. Each of the PEG film-coated citric acid particles is shown.
FIG. 2 shows an internal structure of a mixing apparatus used for carrying out the film forming method of the present invention.
FIG. 3 schematically shows a fluidized bed drying apparatus for solidifying PEG film-coated particles.
[Explanation of symbols]
1 ... mixing container, 2 ... main blade,
3 ... Cross screw, 4 ... Mixing container lid,
5 ... discharge hole, 6 ... inspection window, 7 ... exhaust part,
11 ... Air flow, 12 ... Particles

Claims (10)

A powder comprising an organic acid or a salt thereof and a solid coating agent having a melting point lower than that of the powder are heated and mixed at a heating temperature 5% to 50% lower than the melting point of the coating agent. A granulated powder in which a film made of the coating agent is formed on the particle surface.   The granulated powder according to claim 1, wherein the coating agent is a nonionic surfactant.   The granulated powder according to claim 2, wherein the coating agent is polyethylene glycol.   The granulated powder according to claim 3, wherein the polyethylene glycol has an average molecular weight of 2000 to 20000.   The granulated powder according to claim 3 or 4, wherein 1 to 100 parts by weight of polyethylene glycol is blended with 100 parts by weight of the powder.   A compression-molded solid material obtained by compression-molding the granulated powder according to any one of claims 1 to 5 with another compounding agent as required. A powder comprising an organic acid or a salt thereof and a solid coating agent having a melting point lower than that of the powder are heated and mixed at a heating temperature 5% to 50% lower than the melting point of the coating agent. A method for producing a granulated powder, which comprises forming a film with a coating agent on the particle surface. An organic acid or powder consisting of a salt thereof, and a solid coating agent having a lower melting point than the powder, and other compounding agents, heating and mixing with 5% to 50% lower heating temperature than the melting point of the coating agent And forming a film with a coating agent on the particle surface of the powder.   The method for producing a granulated powder according to claim 8, wherein at least one of menthol, menthol derivative, and menthyl lactate is used as a compounding agent.   10. The structure according to claim 7, 8 or 9, wherein after forming a film with a coating agent on the particle surface of the powder, a cooling substance for reducing the temperature of the coating agent film is added and mixed as a compounding agent. Production method of granular powder.

Images