Method for producing solid particles

Abstract

To provide a method for producing solid particles which suppresses adhesion of fine particles.SOLUTION: There is provided a method for producing solid particles which comprises the following steps 1 to 3: a step 1 of heating a raw material composition comprising an oily component to impart fluidity, a step 2 of discharging and granulating the raw material composition to which fluidity is imparted to form a granular raw material and a step 3 of dropping the granular raw material into a powder to coat the surface of the granular raw material with the powder, wherein in the step 2, when the raw material composition is discharged and granulated in advance, the maximum length of the raw material composition to be elongated is measured and the ratio of the length of the dropping distance of the granular raw material to the maximum length elongated during granulation is set to be more than 0 and 9 or less.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a method for producing solid particles. [Background technology]

[0002] Solid particles such as solid cosmetics that have been known up until now have generally been in the form of powders compressed and molded into a shallow tray, such as foundation, or compositions that are solid at room temperature molded into a specific shape, such as lipstick. In addition to solid cosmetics in such forms, solid cosmetics in granular form (granular solid cosmetics) have been proposed in recent years.

[0003] For example, Patent Document 1 describes a method for producing a granular solid cosmetic product, in which cosmetic raw materials are granulated and a powder is adhered to the surface of the granulated cosmetic raw materials. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent Publication No. 2021-109850 Summary of the Invention [Problem to be solved by the invention]

[0005] The granular solid cosmetic described in Patent Document 1 had a problem in that when the raw materials of the cosmetic were granulated, fine particles were formed in addition to the desired granulated cosmetic, and the fine particles adhered to the granular solid cosmetic.

[0006] The present invention relates to a method for producing solid particles in which adhesion of fine particles is suppressed. [Means for solving the problem]

[0007] The inventors have discovered that when a granular raw material is formed by granulating a raw material composition containing an oily component that has been given fluidity by heating, the granular raw material is dropped into a powder to coat the surface of the granular raw material with powder, and when the raw material composition is dropped from the nozzle outlet in the process of forming the granular raw material, solid particles free of attached fine particles can be obtained in a high yield by determining the length of the dropping distance based on the maximum length that the raw material composition extends from the outlet. The present invention relates to the following [1]. [1] A method for producing solid particles comprising the following steps 1 to 3: Step 1: A step of heating a raw material composition containing an oily component to impart fluidity; Step 2: A step of discharging the raw material composition having been given fluidity to granulate the raw material composition to form a granular raw material; Step 3: dropping the granular raw material into a powder to coat the surface of the granular raw material with the powder; In the step 2, the raw material composition is discharged in advance, a maximum length that the raw material composition extends during granulation is measured, and a ratio of a dropping distance of the granular raw material to the maximum length that the raw material composition extends during granulation is set to be greater than 0 and not greater than 9. Effect of the Invention

[0008] According to the production method of the present invention, it is possible to provide solid particles free of fine particles adhering thereto. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is a schematic diagram showing the mechanism by which fine particles adhere to solid particles. [Diagram 2] FIG. 2 is a schematic diagram showing one embodiment of the production method of the present invention. [Diagram 3] FIG. 3 is a schematic diagram showing one embodiment of the production method of the present invention using a vibrating feeder. [Figure 4] FIG. 4 is a schematic diagram showing a solid particle with no fine particles attached. [Diagram 5]FIG. 5 is a schematic diagram showing a solid particle having fine particles attached thereto. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] BRIEF DESCRIPTION OF THE DRAWINGS The present invention relates to a method for producing solid particles.

[0011] [Method of manufacturing solid particles] The method for producing solid particles of the present invention includes the following steps 1 to 3: Step 1: A step of heating a raw material composition containing an oily component to impart fluidity; Step 2: A step of discharging the raw material composition having been given fluidity to granulate the raw material composition to form a granular raw material; Step 3: dropping the granular raw material into a powder to coat the surface of the granular raw material with the powder; In step 2, the raw material composition is discharged in advance, and the maximum length that the raw material composition extends during granulation is measured, and the length of the dripping distance of the granular raw material is set so that the ratio of the dripping distance to the maximum length that the raw material composition extends during granulation is greater than 0 and less than or equal to 9. In this specification, the term "raw material" in "raw material composition" and "granular raw material" refers to the raw material of solid particles that are the product, and does not limit the material, etc.

[0012] The method for producing solid particles of the present invention has the effect of producing solid particles free of fine particles with high yield. The reason for this effect is believed to be as follows. The inventors have found that when a raw material composition containing an oily component that has been given fluidity by heating is discharged to form granular raw material, and the granular raw material is dropped into a powder, the raw material composition extends to form a liquid column, and when the granular raw material is cut off and separated from the liquid column, fine particles are formed in addition to the granular raw material. It is believed that these fine particles fall in the same trajectory as the granular raw material, and adhere to the granular raw material when dropped into the powder, resulting in solid particles with fine particles attached (hereinafter also referred to as "fine-particle-attached solid particles").

[0013] The mechanism by which the fine particle-adhered solid particles are generated and the effects of the present invention will be described in detail below with reference to FIG. 1. A raw material composition 10, which is made fluid by heating the raw material composition, is sent using a pump 11 or the like and discharged from the tip of a nozzle 12. When the raw material composition is dropped, it is stretched and cut, and granulated, forming a granular raw material 13 and fine particles 14. The granular raw material 13 and the fine particles 14 have the same falling trajectory, but the fine particles 14 fall later than the granular raw material. The present inventors have found that when the granular raw material 13 is dropped into a powder 15, the granular raw material 13 is rapidly cooled, and the fine particles 14 that fall later land at a position slightly offset from the center of the cooled granular raw material 13 in the vertical direction, they do not coalesce with the granular raw material 13, and the fine particles 2 attached to the granular raw material 13 are obtained. When the fine particles 14 land at a position almost identical to the center of the granular raw material 13 in the vertical direction, the fine particles 14 are united with the granular raw material 13 to form one granular raw material 13, and when the fine particles 14 fall at a position shifted from the center of the granular raw material 13 by a distance greater than the radius, the surfaces of the dropped granular raw material 13 and the fine particles 14 are covered with powder 15 (hereinafter, the granular raw material 13 and the fine particles 14 covered with powder are referred to as "solid particles 1" and "satellite particles 3", respectively), so that the two particles do not adhere to each other. It was also found that when the dropping distance from the tip of the nozzle 12 to the surface of the powder 15 is short to a certain extent, the fine particles 14 are not produced as a by-product.

[0014] Based on the above findings, various studies were conducted and it was found that by measuring in advance the maximum length that extends when the raw material composition is granulated by ejecting it, and setting the length of the dripping distance of the granular raw material so that the ratio to the maximum length that extends when granulated is within a specific range, fine particles 14 are not produced as a by-product as described above, or even if fine particles 14 are produced as a by-product, the fine particles 14 will impact the granular raw material 13 directly in the vertical direction before the granular raw material 13 is cooled, thereby causing the granular raw material 13 and the fine particles 14 to coalesce, and spherical solid particles without any fine particles adhering thereto can be obtained in a high yield.

[0015] In the present invention, the term "fine particles" refers to particles that are generated by-products during the formation of a granular raw material and have a smaller particle size than the granular raw material. Specifically, fine particles are particles whose diameter is less than one-third the diameter of the granular raw material. In addition, in this specification, "coalescence", such as when the granular raw material 13 and the fine particles 14 coalesce, means that the fine particles 14 are taken up into the granular raw material 13 and become indistinguishable in appearance, and "adhesion", such as when the fine particles 14 adhere to the granular raw material 13, means that the fine particles 14 and the granular raw material 13 form a single particle in a state in which the part derived from the fine particles 14 and the part derived from the granular raw material 13 are distinguishable in appearance.

[0016] An example of the method for producing solid particles of the present invention will be described below with reference to FIG. 2. Step 1 is a step of heating the raw material composition to obtain a raw material composition 10 having fluidity. Step 2 is a step of granulating the raw material composition 10 having fluidity to form a granular raw material 13. In FIG. 2, the raw material composition 10 having fluidity is pumped using a pump 11 and discharged from the tip of a nozzle 12, where the raw material composition 10 is stretched and cut to form the granular raw material 13. Step 3 is a step of dropping the granular raw material 13 into a powder 15, and in some cases, fine particles 14 produced as a by-product by the stretching and cutting of the raw material composition 10 are united with the granular raw material 13, and the powder 15 is attached to the granular raw material 13 to cover the surface of the granular raw material 13 with the powder 15, thereby obtaining solid particles 1. In the manufacturing method of the present invention, coating the surface of the granular raw material 13 with the powder 15 means not only that the entire surface of the granular raw material 13 is coated with the powder 15, but also that at least a portion of the surface of the granular raw material 13 is coated with the powder 15. From the viewpoint of improving adhesion resistance and transport durability, it is preferable that the entire surface of the granular raw material 13 is coated with the powder 15.

[0017] [Process 1] Step 1 is a step of heating a raw material composition containing an oily component to impart fluidity. By heating to a temperature equal to or higher than the melting point of at least one substance contained in the raw material composition, a raw material composition 10 imparted with fluidity can be obtained. In addition, it is preferable to heat to a temperature equal to or higher than the melting point of the raw material composition. The temperature for imparting fluidity to the raw material composition in step 3 is preferably 60° C. or higher, more preferably 70° C. or higher, even more preferably 80° C. or higher, and even more preferably 85° C. or higher, from the viewpoint of delaying solidification of the granular raw material 13 and promoting adhesion of the powder 15. In addition, from the viewpoint of preventing deterioration of the raw material composition due to heat, the temperature is preferably 150° C. or lower, more preferably 130° C. or lower, even more preferably 120° C. or lower, and even more preferably 115° C. or lower. In particular, the temperature for imparting fluidity to the raw material composition is preferably 60° C. or higher and 150° C. or lower, more preferably 70° C. or higher and 130° C. or lower, even more preferably 80° C. or higher and 120° C. or lower, and even more preferably 85° C. or higher and 115° C. or lower.

[0018] [Process 2] Step 2 is a step of granulating the raw material composition 10 to which fluidity has been imparted to form granular raw material 13. When the raw material composition 10 to which fluidity has been imparted as shown in Fig. 2 is a liquid obtained by heating the raw material composition to a melting point or higher, the raw material composition 10 sent by the pump 11 is discharged from the tip of the nozzle 12, and the raw material composition 10 is stretched and cut to form the granular raw material 13 as droplets. In addition, the device for forming the granular raw material 13 from the raw material composition 10 to which fluidity has been imparted is not limited to the device shown in Fig. 2, and a known droplet manufacturing device or the like can be used.

[0019] The maximum length of the raw material composition 10 to which fluidity has been imparted is measured in advance when the raw material composition 10 is granulated by being discharged. This maximum length is affected not only by the raw material composition 10 but also by conditions such as the discharge temperature and flow rate in step 2, and is specific to each manufacturing condition, so it is necessary to measure it before carrying out the present invention. In step 2, if the length of the dripping distance of the granular raw material 13 is set so that the ratio to the maximum length of the raw material composition 10 to be granulated is greater than 0 and less than 9, when the ratio is greater than 0 and less than 1, fine particles 14 are difficult to form, depending on the viscosity of the raw material composition 10, and when the ratio is greater than 1 or more and less than 9, fine particles 14 are formed, but when the granular raw material 13 is dripped into the powder 15 in step 3, the granular raw material 13 and the fine particles 14 are united, so that solid particles without fine particles attached can be obtained in high yield. The ratio of the length of the dripping distance of granular raw material 13 to the maximum length extended when raw material composition 10 is granulated is preferably 0.1 or more, and more preferably 0.2 or more, from the viewpoint of stably obtaining granular raw material 13 of uniform size, and is preferably 8.5 or less, more preferably 8 or less, even more preferably 6 or less, and even more preferably 5.5 or less, from the viewpoint of making it difficult to produce fine particles 14 as a by-product or of uniting the by-produced fine particles 14 with granular raw material 13 to obtain solid particles 13 without fine particles 14 adhering thereto. The distance over which the granular raw material 13 is dropped, i.e., the distance between the tip of the nozzle 12 and the outermost surface of the layer of powder 15, is preferably 200 mm or less, more preferably 170 mm or less, even more preferably 150 mm or less, still more preferably 120 mm or less, and even more preferably 90 mm or less, from the viewpoint of mitigating the impact of the dropped granular raw material 13 coming into contact with the powder 15, preventing deformation, suppressing cooling of the granular raw material 13 during dropping, and coalescing the granular raw material 13 with the fine particles 14. The dropping distance is longer than 0 mm, i.e., it is sufficient that the powder 15 and the nozzle 12 are not in contact, and is preferably 2 mm or more, more preferably 3 mm or more, and even more preferably 4 mm or more, from the viewpoint of forming the granular raw material 13 into a spherical shape. The maximum length that the raw material composition 10 extends when granulated is the distance between the tip of the nozzle 12 and the lower end of a droplet (hereinafter also referred to as "mother particle") formed at the tip of the extended raw material composition 10 just before the extended raw material composition 10 is cut at any point to form the granular raw material 13 when the raw material composition 10 is liquefied and discharged from the nozzle 12 with a sufficiently long dripping distance. The distance at which the granular raw material 13 is dripped in the present invention depends on the maximum length that the raw material composition 10 extends as described above, and the length is affected by the outer diameter of the nozzle 12, the composition and temperature of the raw material composition 10, and the flow rate at which the raw material composition 10 is discharged from the nozzle 12. Therefore, if the above conditions for producing the granular raw material 13 change, the distance needs to be reset each time. The timing of "just before" is determined by the method described in the examples. The maximum length that the raw material composition 10 extends when granulated is preferably 25 mm or less, more preferably 20 mm or less, and even more preferably 18 mm or less, from the viewpoint of obtaining solid particles without fine particles attached by combining the granular raw material with the fine particles. Note that there is no lower limit because the problem of the present invention does not occur if the raw material composition 10 does not extend when granulated. Usually, if the length that the raw material composition 10 extends when granulated is 2 mm or more, solid particles with fine particles attached may be generated. The maximum length that the raw material composition 10 extends when it is granulated can be measured by the method described in the Examples.

[0020] The solid particles 1, which are the object of the manufacturing method of the present invention, are composed of a core and a shell made of a layer of raw material composition incorporating powder that covers the core, and therefore the size of the solid particles 1 is approximately the same as or slightly larger than the granular raw material 13 formed in step 2. In other words, the size of the granular raw material 13 is preferably adjusted based on the average projected area, diameter, and / or weight of the solid particles 1 to be obtained when placed on a flat surface. The particle diameter of the granular raw material 13 is mainly correlated with the outer diameter of the nozzle, and the larger the outer diameter of the nozzle, the larger the particle diameter of the granular raw material 13. For this reason, for example, when the granular raw material 13 is formed as droplets by ejecting the liquid raw material composition 10 from the tip of the nozzle 12, the outer diameter of the nozzle 12 can be changed according to the particle diameter of the target solid particles. From the viewpoint of obtaining a particle diameter according to the amount of solid particles 1 used per time, the outer diameter of the nozzle 12 is preferably 0.5 mm or more, more preferably 1 mm or more, and even more preferably 1.5 mm or more. In addition, from the viewpoint of stably dripping the granular raw material 13, it is preferably 20 mm or less, more preferably 10 mm or less, and even more preferably 5 mm or less. In particular, the outer diameter of the nozzle 12 is preferably 0.5 mm or more and 20 mm or less, more preferably 1 mm or more and 10 mm or less, and even more preferably 1.5 mm or more and 5 mm or less.

[0021] [Step 3] Step 3 is a step of dropping granular raw material 13 into powder 15, uniting granular raw material 13 and fine particles 14 as necessary, and coating the surface of granular raw material 13 with powder 15. Powder 15 may be contained in container 16. When using an apparatus such as that shown in FIG. 3 described later, powder 15 falls onto sieve 24 by the operation of vibration feeder 23, and a powder supplying device may be arranged to continuously supply powder 15 on trough 21 to a constant amount in accordance with the falling speed. In this step, the "granular raw material 13" also includes the granular raw material 13 and the fine particles 14 that have been combined together. The thickness of the layer of powder 15 is preferably 50 mm or more, more preferably 60 mm or more, and even more preferably 70 mm or more from the viewpoint of promoting adhesion of powder 15 to the upper part of dropped granular raw material 13, and is preferably 250 mm or less, more preferably 230 mm or less, and even more preferably 210 mm or less from the viewpoint of avoiding the use of excessive powder. When using an apparatus such as that shown in FIG. 3 described later, the thickness of the layer of powder 15 is preferably 3 mm or more, more preferably 5 mm or more, and even more preferably 8 mm or more from the viewpoint of promoting adhesion of powder 15 to the upper part of dropped granular raw material 13, and is preferably 50 mm or less, more preferably 30 mm or less, more preferably 20 mm or less, and even more preferably 15 mm or less from the viewpoint of avoiding the use of excessive powder.

[0022] From the viewpoint of delaying solidification of the granular raw material 13 and promoting adhesion of the powder 15, the temperature of the powder 15 is preferably 5° C. or higher, more preferably 15° C. or higher, and even more preferably 20° C. or higher. Moreover, from the viewpoint of suppressing excessive adhesion of the powder 15 to the granular raw material 13, the temperature of the powder 15 is preferably 60° C. or lower, more preferably 55° C. or lower, even more preferably 50° C. or lower, and even more preferably 30° C. or lower. In particular, the temperature of the powder 15 is preferably 5° C. or higher and 60° C. or lower, more preferably 15° C. or higher and 55° C. or lower, even more preferably 20° C. or higher and 50° C. or lower, and even more preferably 20° C. to 30° C. (room temperature).

[0023] The time for covering the surface of the granular raw material 13 with the powder 15 is preferably 2 seconds or more, more preferably 3 seconds or more, and even more preferably 4 seconds or more, from the viewpoint of promoting adhesion of the powder to the surface of the granular raw material 13. Moreover, from the viewpoint of productivity, the time for covering the surface of the granular raw material 13 with the powder 15 is preferably 24 hours or less, more preferably 12 hours or less, and even more preferably 6 hours or less.

[0024] By stirring the powder 15 with the stirrer 17, the granular raw material 13 dropped into the powder 15 moves from the dropping position before the next granular raw material 13 is dropped, thereby preventing the granular raw materials 13 from adhering to each other.

[0025] The step of covering the surface of the granular raw material 13 with the powder 15 may be performed in a state in which the powder 15 is vibrated. For example, in FIG. 3, a vibration feeder 23 having a trough 21 installed on a vibration device 22 is used to apply vibration to the powder 15 on the trough 21. By dropping the granular raw material 13 onto the vibrated powder 15, the surface of the granular raw material 13 can be covered with the powder 15 in a state in which the powder 15 is vibrated. At this time, it is preferable that the powder 15 is continuously supplied onto the trough 21 by a powder supplying device (not shown). By bringing the granular raw material 13 into contact with the powder 15 while the powder 15 is being vibrated, and causing the powder 15 to adhere to the granular raw material 13 and coat the surface of the granular raw material 13 with the powder 15, the powder 15 can be incorporated to a depth of at least about 80 μm from the surface of the granular raw material 13, and solid particles with excellent adhesion resistance and transport resistance are obtained. Also, a bowl may be used instead of the trough 21 as a container for containing the powder 15. By using a bowl feeder in which a bowl is placed on a vibrating device, the granular raw material that comes into contact with the vibrated powder rises up the slope provided on the inner wall of the bowl due to the vibration while its surface is covered with the powder. When the trough 21 is used to extend the time that the granular raw material is in contact with the powder, the trough must be made longer, but when a bowl is used, it is only necessary to extend the number of turns of the spiral of the slope in the height direction, which is space efficient.

[0026] The amplitude of vibration given to the powder 15 when the surface of the granular raw material 13 is covered with the powder 15 is preferably 0.3 mm or more, more preferably 0.4 mm or more, even more preferably 0.5 mm or more, and even more preferably 0.6 mm or more, from the viewpoint of promoting adhesion of the powder 15 to the surface of the granular raw material 13. And, it is preferably 5 mm or less, more preferably 4 mm or less, even more preferably 3 mm or less, further more preferably 1.5 mm or less, further more preferably 1.4 mm or less, and even more preferably 1.3 mm or less. In particular, the amplitude of vibration is preferably 0.3 mm or more and 5 mm or less, more preferably 0.4 mm or more and 4 mm or less, further more preferably 0.5 mm or more and 4 mm or less, further more preferably 0.5 mm or more and 3 mm or less, further more preferably 0.6 mm or more and 3 mm or less, further more preferably 0.3 mm or more and 1.5 mm or less, further more preferably 0.4 mm or more and 1.4 mm or less, further more preferably 0.5 mm or more and 1.3 mm or less, and further more preferably 0.6 mm or more and 1.3 mm or less. The amplitude of the vibration applied to the powder 15 is preferably measured at a position directly above the vibration device 22 . From the viewpoint of promoting adhesion of the powder 15 to the surface of the granular raw material 13, the vibration frequency is preferably 30 Hz or more, more preferably 40 Hz or more, and even more preferably 50 Hz or more. And, it is preferably 300 Hz or less, more preferably 100 Hz or less, even more preferably 75 Hz or less, and even more preferably 60 Hz or less. In particular, the vibration frequency is preferably 30 Hz or more and 300 Hz or less, more preferably 40 Hz or more and 100 Hz or less, even more preferably 50 Hz or more and 75 Hz or less, and even more preferably 50 Hz or more and 60 Hz or less.

[0027] The time for covering the surface of the granular raw material 13 with the powder 15 in the apparatus shown in Fig. 3 is preferably 2 seconds or more, more preferably 3 seconds or more, and even more preferably 4 seconds or more, from the viewpoint of promoting adhesion of the powder to the surface of the granular raw material 13. Moreover, from the viewpoint of productivity, the time for covering the surface of the granular raw material 13 with the powder 15 is preferably 300 seconds or less, more preferably 200 seconds or less, and even more preferably 100 seconds or less. In particular, the time for covering the surface of the granular raw material 13 with the powder 15 is preferably 2 seconds or more and 300 seconds or less, more preferably 3 seconds or more and 200 seconds or less, and even more preferably 4 seconds or more and 100 seconds or less.

[0028] By the above-mentioned step 3, the powder 15 is adhered to the surface of the granular raw material 13, and the surface of the granular raw material 13 is covered with the powder 15, whereby the solid particles 1 can be obtained.

[0029] (cooling process) A step of cooling the granular raw material 13 may be included as an additional step simultaneously with covering the surface of the granular raw material 13 with the powder 15 and / or after step 3. By cooling, the adhesion of the powder 15 to the granular raw material 13 can be made more reliable. The cooling may be, for example, natural cooling or forced cooling. In the case of natural cooling, the solid particles 1 having the surface of the granular raw material 13 coated with the powder 15 may be allowed to stand at room temperature. In the case of forced cooling, gas may be blown onto the solid particles 1, the solid particles 1 may be placed in a refrigerator, or the solid particles 1 may be brought into contact with a refrigerant.

[0030] At the time when the surface of the granular raw material 13 is coated with the powder 15, the granular raw material 13 is softened. The granular raw material 13 whose surface is coated with the powder 15 is solidified at some subsequent stage. "Solidification" refers to the hardness of the granular raw material 13 becoming the hardness of the raw material composition before being given fluidity through cooling.

[0031] The portion of the granular raw material 13 that does not contain the powder 15 formed by solidifying the granular raw material 13 is the core of the solid particle 1. The granular raw material 13 is formed by granulating the raw material composition and is in a state before solidification. The portion inside the granular raw material 13 near the surface where the raw material composition incorporates the powder 15 is the shell of the solid particle 1.

[0032] After step 3, prior to, after, or simultaneously with cooling of the solid particles 1, it is possible to remove the powder 15 that is not adhered to the surfaces of the solid particles 1. The powder 15 that is not adhered to the surfaces of the solid particles 1 refers to powder 15 that is weakly adhered to the extent that it falls off from the solid particles 1 due to an external force such as vibration applied when the solid particles 1 are transported, or that is not adhered at all to the portions derived from the raw material composition. The powder can be removed using a sieve with openings large enough to prevent the passage of the solid particles 1. Alternatively, as shown in Fig. 3, the mixture may be transported on a trough 21, and the solid particles 1 may be separated from the powder 15 and satellite particles 3 by a sieve 24. Alternatively, the mixture of the powder 15 and the satellite particles 3 may be separated by a separate sieve, and the powder 15 may be reused.

[0033] [Solid particles] The solid particles produced by the production method of the present invention (hereinafter also referred to as "solid particles of the present invention") are solid particles having a core-shell structure, which has a core made of a granular solid raw material composition and a shell covering at least a part of the surface of the core. The shell is made of a layer of the raw material composition incorporating powder, and the powder may be multi-layered or single-layered, and there may be gaps between the particles constituting the powder.

[0034] The solid particles of the present invention have improved strength in the vicinity of the surface of the solid particles due to the adhesion of the powder and incorporation into the raw material composition, and therefore are considered to be able to suppress crushing, deformation, crushing, or collapse of the solid particles due to contact between the particles or between the particles and the container during transportation. This suppresses exposure of the core and suppresses adhesion between the solid particles, and is considered to have excellent transport resistance. Furthermore, the presence of the powder near the surface suppresses deterioration of the feeling of use. The term "solid particles" refers to particles that are solid at room temperature (25° C.) and have the property of softening or melting and becoming fluid when heated to a temperature higher than room temperature, for example, 50° C. or higher. To obtain such solid particles, for example, a raw material composition having a melting point of 50° C. or higher may be used, as described below.

[0035] [Shape of solid particles] The size of the solid particles is not particularly limited, but from the viewpoints of ease of use such as ease of handling, difficulty in rolling, ease of crushing, design, ease of manufacture, etc., the average projected area when placed on a flat surface is preferably 0.5 mm 2 More than 1mm, preferably 1mm 2 More preferably 1.5 mm 2 The solid particles preferably have an average projected area of ​​320 mm or less from the standpoint of ease of use (e.g., ease of handling), ease of crushing, and design. 2 Less than or equal to 80mm, more preferably 2 Less than 20 mm, more preferably 2 In particular, the solid particles preferably have an average projected area of ​​0.5 mm 2 More than 320mm 2 Less than 1mm, more preferably 2 More than 80mm 2 Less than 1.5 mm, more preferably 2 More than 20mm 2 The term "average projected area" refers to the number average value of the area of ​​10 randomly selected solid particles projected onto a horizontal surface when the solid particles are placed on the horizontal surface in the most stable state when exposed to light coming from directly above.

[0036] When the solid particles are spherical or nearly spherical, their diameter is preferably 0.5 mm or more, more preferably 1 mm or more, even more preferably 1.5 mm or more, and preferably 20 mm or less, more preferably 10 mm or less, even more preferably 5 mm or less. The diameter of the spherical or nearly spherical solid particles is preferably 0.5 mm or more and 20 mm or less, more preferably 1 mm or more and 10 mm or less, even more preferably 1.5 mm or more and 5 mm or less. When the solid particles are oblate or approximately oblate spheroidal, their diameter is the equivalent circle diameter determined from the above horizontal projection, and is preferably 0.5 mm or more, more preferably 1 mm or more, even more preferably 1.5 mm or more, and preferably 20 mm or less, more preferably 10 mm or less, even more preferably 5 mm or less. The diameter of the oblate or approximately oblate spheroidal solid particles is preferably 0.5 mm or more and 20 mm or less, more preferably 1 mm or more and 10 mm or less, even more preferably 1.5 mm or more and 5 mm or less. Furthermore, when the solid particles are oblate or approximately oblate spheroidal, their height is the distance between the surface in contact with the solid particles, which is horizontal to the horizontal surface on which the solid particles are placed and located at the furthest position, and the horizontal surface, and is preferably 0.4 mm or more, more preferably 0.8 mm or more, even more preferably 1.2 mm or more, and is preferably 16 mm or less, more preferably 8 mm or less, even more preferably 4 mm or less. The height of the oblate or approximately oblate spheroidal solid particles is preferably 0.4 mm or more and 16 mm or less, more preferably 0.8 mm or more and 8 mm or less, even more preferably 1.2 mm or more and 4 mm or less.

[0037] The average mass per solid particle is preferably 1 mg or more, more preferably 5 mg or more, and even more preferably 10 mg or more. The mass per solid particle is preferably 10,000 mg or less, more preferably 5,000 mg or less, and even more preferably 1,000 mg or less. The mass of the solid particle is preferably 1 mg or more and 10,000 mg or less, more preferably 5 mg or more and 5,000 mg or less, and even more preferably 10 mg or more and 1,000 mg or less. The "average mass" means the number average value of the masses of 10 randomly selected solid particles.

[0038] Although it depends on the properties of the powder and the manufacturing conditions, the thickness of the shell part of the solid particles is preferably 80 μm or more from the viewpoint of improving adhesion resistance and transport resistance, more preferably 100 μm or more, even more preferably 110 μm or more, even more preferably 120 μm or more, even more preferably 130 μm or more, and even more preferably 150 μm or more. In particular, if the thickness of the shell part is 110 μm or more, the adhesion resistance and transport resistance of the solid particles are further improved, which is preferable. In addition, from the viewpoint of suppressing deterioration of the feeling of use, it is preferably 300 μm or less, more preferably 250 μm or less, and even more preferably 200 μm or less. The thickness of the shell portion includes cases where the shell portion is made up of multiple layers of powder having a diameter smaller than the thickness, and cases where the shell portion is made up of a single layer of powder having a diameter equal to the thickness.

[0039] The content of the powder in the solid particles is preferably 5.0% by mass or more, more preferably 7.0% by mass or more, even more preferably 7.5% by mass or more, and even more preferably 8.0% by mass or more, in terms of improving adhesion resistance and transport resistance, and is preferably 30% by mass or less, more preferably 20% by mass or less, even more preferably 15% by mass or less, even more preferably 13% by mass or less, and even more preferably 12% by mass or less, in terms of not affecting the feeling of use.

[0040] The average strength per solid particle is preferably 0.14N or more, more preferably 0.16N or more, from the viewpoint of transport resistance. The average strength per solid particle is preferably 3N or less, more preferably 1N or less, from the viewpoint of usability. The average strength of the solid particles is preferably 0.14N or more and 3N or less, more preferably 0.16N or more and 1N or less. "Average strength" means the number average value of the strength of 10 randomly selected solid particles. The strength of the solid particles is measured by the method described in the Examples.

[0041] [Solid particle raw materials] [Raw material composition] The raw material composition is solid at room temperature (25°C), and has a melting point of preferably 50°C or higher, more preferably 55°C or higher, and even more preferably 60°C or higher. Since the granular raw material obtained by granulating the raw material composition becomes the core of the solid particles, the raw material composition having a melting point of this temperature or higher can improve the feel when used as a cosmetic product when the solid particles are used. In addition, from the viewpoint of ease of production, the raw material composition has a melting point of preferably 150°C or lower, more preferably 120°C or lower, and even more preferably 110°C or lower. In addition, the raw material composition having a melting point of this temperature or lower can also improve the feel when used as a cosmetic product. In particular, the melting point of the raw material composition is preferably 50°C or higher and 150°C or lower, more preferably 55°C or higher and 120°C or lower, and even more preferably 60°C or higher and 110°C or lower.

[0042] The raw material composition usually contains multiple substances. In this case, the melting point of the raw material composition is measured by either method 1, 2, or 3 of the general test method for quasi-drug raw materials. The method to be used is mainly selected depending on the melting point of the raw material composition. When the melting point is high, such as over 75°C, method 1 can be used, when the melting point is between 50°C and 75°C, method 2 can be used, and when the melting point is below 50°C, method 3 can be used.

[0043] The raw material composition is preferably a cosmetic raw material composition, from the viewpoint that the solid particles of the present invention are preferably used as cosmetics. The feed composition preferably has a continuous phase comprised of one or more oil-based components, and optionally includes a powder component, such as a pigment, dispersed in the continuous phase. Examples of the oily component include hydrocarbon oil, ester oil, ether oil, fatty acid, alcohol, silicone oil, fluorine oil, etc. The number of carbon atoms in the oily component is preferably 6 or more, more preferably 10 or more, and is preferably 50 or less, more preferably 30 or less. Specifically, mineral waxes such as ozokerite and ceresin; petroleum waxes such as paraffin and microcrystalline wax; synthetic hydrocarbons such as Fischer-Tropsch wax, polyethylene wax, and synthetic wax; plant waxes such as carnauba wax, candelilla wax, rice wax, sunflower wax, hydrogenated jojoba oil, and Japan wax; animal waxes such as beeswax and spermaceti; synthetic waxes such as silicone wax, synthetic beeswax, and synthetic Japan wax; oil-based gelling agents such as dextrin palmitate, sucrose fatty acid esters, inulin stearate, 12-hydroxystearic acid, dibutyl lauroyl glutamide, dibutyl ethylhexanoyl glutamide, and polyamide resins; petrolatum, vinyl leather wax, dipentaerythrityl hexa(behenate / benzoate / ethylhexanoate), cholesteryl hydroxystearate, dipentaerythrityl tetra(hydroxystearate / isostearate), water Additive palm oil, dipentaerythrityl hexahydroxystearate, tri(caprylic acid / capric acid / myristic acid / stearic acid)glyceryl, dipentaerythrityl hexa(hydroxystearate / stearic acid / rosin acid), phytosteryl oleate, glyceryl (ethylhexanoate / stearic acid / adipic acid), di(octyldodecyl / phytosteryl / behenyl) lauroyl glutamate, phytosteryl / isostearyl dimer dilinoleate Paste oils such as bis(cetyl / stearyl / behenyl), dimer dilinoleyl dimer dilinoleate bis(behenyl / isostearyl / phytosteryl), hard lanolin, reduced lanolin, bis-diglyceryl polyacyladipate-2, etc.; linear or branched hydrocarbon oils such as liquid paraffin, light liquid isoparaffin, heavy liquid isoparaffin, mineral oil, squalane, α-olefin oligomer, polyisobutylene, polybutene, hydrogenated polyisobutene, hydrogenated polydecene, etc.;Isononyl isononanoate, isodecyl isononanoate, isotridecyl isononanoate, tricyclodecane methyl isononanoate, ethyl isostearate, isobutyl isostearate, isopropyl isostearate, 2-hexyldecyl isostearate, di-2-ethylhexyl succinate, bis-ethoxydiglycol succinate, hexyl laurate, dicaprylic / capric acid propanediol, neopentyl glycol diisononanoate, neopentyl glycol dicaprate, glyceryl diisostearate, polyglyceryl diisostearate , Propanediol diisostearate, Trimethylolpropane triisostearate, Glyceryl triisostearate, Diglyceryl triisostearate, Diglyceryl tetraisostearate, Diisostearyl malate, Octyldodecyl malate, Glycerin fatty acid ester, Jojoba oil, Di(phytosteryl / octyldodecyl) lauroyl glutamate, Octyldodecyl myristate, Isopropyl myristate, 2-ethylhexyl palmitate, Isopropyl palmitate, Cetyl 2-ethylhexanoate, Tri-2-ethylhexyl Trimethylolpropane Phosphate, Glyceryl Tri-2-Ethylhexanoate, Octyldodecyl Myristate, 2-Hexyldecyl Myristate, 2-Hexyldecyl 2-Ethylhexanoate, Neopentyl Glycol Di-2-Ethylhexanoate, Ethylhexyl Hydroxystearate, Caprylic / Capric Triglyceride, Glyceryl Trioctanoate, Neopentyl Glycol Dioctanoate, Tridecyl Trimellitate, Dipentaerythrityl Tetraisostearate, Pentaerythrityl Tetraisostearate, Octyl Methoxycinnamate, Panthenol Ester oils such as 2-ethylhexyl methoxycinnamate, diisopropyl dimerate, and propylene carbonate; higher alcohols such as lauryl alcohol, oleyl alcohol, isostearyl alcohol, behenyl alcohol, and octyldodecanol; silicone oils such as dimethylpolysiloxane, dimethylcyclopolysiloxane, methylphenylpolysiloxane, trimethylpentaphenyltrisiloxane, methylhydrogenpolysiloxane, higher alcohol-modified organopolysiloxane, and bisalkyl (C16-18) glycerin undecyl dimethicone;Examples of the oily components include fluoro oils such as fluoropolyether, perfluoroalkyl ether silicone, and fluorine-modified silicone; tocopherol, dipropylene glycol, and phenoxyethanol. These oily components may be used alone or in combination of two or more.

[0044] From the viewpoint of the feeling of use of the solid particles, the raw material composition contains an oil component of preferably 40% by mass or more, more preferably 50% by mass or more, even more preferably 60% by mass or more, even more preferably 70% by mass or more, and even more preferably 75% by mass or more. From the same viewpoint, the raw material composition contains an oil component of preferably 100% by mass or less, more preferably 99% by mass or less, even more preferably 98% by mass or less, even more preferably 97% by mass or less, and even more preferably 95% by mass or less. In particular, the raw material composition contains an oil component of preferably 40% by mass or more and 100% by mass or less, more preferably 50% by mass or more and 99% by mass or less, even more preferably 60% by mass or more and 98% by mass or less, even more preferably 70% by mass or more and 97% by mass or less, and even more preferably 75% by mass or more and 95% by mass or less.

[0045] The raw material composition preferably contains an oil component (e.g., the above-mentioned wax) that is solid at 20°C (having a melting point exceeding 20°C) from the viewpoint of enhancing the shape retention of the solid particles. The raw material composition preferably contains 5% by mass or more, more preferably 7% by mass or more of the oil component that is solid at 20°C from the viewpoint of the shape retention of the solid particles. The raw material composition preferably contains 30% by mass or less, more preferably 10% by mass or less of the oil component that is solid at 20°C from the viewpoint of the feeling of use of the solid particles. In particular, the raw material composition preferably contains 5% by mass or more and 30% by mass or less, more preferably 7% by mass or more and 10% by mass or less of the oil component that is solid at 20°C. In addition, the raw material composition preferably contains an oil component that is liquid at 20°C (having a melting point of 20°C or less) from the viewpoint of enhancing the feeling of use of the solid particles. From this viewpoint, the raw material composition preferably contains 18% by mass or more, more preferably 25% by mass or more, and even more preferably 35% by mass or more of the oil component that is liquid at 20°C. From the same viewpoint, the raw material composition contains preferably 95% by mass or less, more preferably 93% by mass or less, and even more preferably 90% by mass or less of an oil component that is liquid at 20° C. In particular, the raw material composition contains preferably 18% by mass or more and 95% by mass or less, more preferably 25% by mass or more and 93% by mass or less, and even more preferably 35% by mass or more and 90% by mass or less of an oil component that is liquid at 20° C.

[0046] Whether an oily component is liquid at 20°C can be determined by the contents described in the safety data sheet (SDS) and physical state of each component. If the raw material composition contains an oily component that is liquid at 20°C in the above-mentioned range, the oily component will be present on the surface of the core part of the solid particles after production, which makes the core part more likely to bond with other substances. In contrast, the solid particles produced by the production method of the present invention have a core part whose surface is covered with a shell part, which suppresses unintended bonding between the solid particles themselves or with other substances, and has adhesion resistance.

[0047] As the powder component contained in the raw material composition, various powders conventionally used in cosmetics can be used without any particular limitation. The powder component may be an inorganic powder or an organic powder. Inorganic powder and organic powder may be used in combination. The shape of the particles constituting the powder component is not particularly limited, and may be, for example, spherical, polyhedral, flake-like, spindle-like, fibrous, amorphous, or a combination thereof.

[0048] As the powder component contained in the raw material composition, for example, pigments such as color pigments, luster pigments and extender pigments can be used, and inorganic powder pigments are preferred. Examples of color pigments include metal oxides such as titanium oxide, zinc oxide, yellow iron oxide, red iron oxide, black iron oxide, Prussian blue, ultramarine blue, chromium oxide, and chromium hydroxide; metal complexes such as manganese violet and cobalt titanate; inorganic pigments such as carbon black; synthetic organic pigments such as Red No. 3, Red No. 104, Red No. 106, Red No. 201, Red No. 202, Red No. 204, Red No. 205, Red No. 220, Red No. 226, Red No. 227, Red No. 228, Red No. 230, Red No. 401, Red No. 405, Red No. 505, Orange No. 203, Orange No. 204, Orange No. 205, Yellow No. 4, Yellow No. 5, Yellow No. 401, Blue No. 1, and Blue 404; and natural organic pigments such as β-carotene, caramel, and paprika color. Examples of luster pigments include those obtained by coating the surface of plate-like powders such as mica, synthetic fluorophlogopite, glass, silica, alumina, talc, etc. with colorants such as titanium oxide, iron oxide, silicon oxide, Prussian blue, chromium oxide, tin oxide, chromium hydroxide, gold, silver, carmine, organic pigments such as Red No. 202 and Yellow No. 4, and original film rolls such as polyethylene terephthalate-polymethyl methacrylate laminated powder, polyethylene terephthalate-aluminum vapor-deposited powder, and polyethylene terephthalate-gold vapor-deposited laminated powder, cut into any desired shape. Examples of extender pigments include inorganic powders such as silica, mica, synthetic fluorophlogopite, glass powder, barium sulfate, kaolin, bentonite, hectorite, zeolite, bismuth oxychloride, zirconium oxide, magnesium oxide, aluminum oxide, calcium sulfate, barium sulfate, magnesium sulfate, calcium carbonate, magnesium carbonate, and talc. Further examples include silicone elastomers such as nylon, polyethylene, (vinyl dimethicone / methicone silsesquioxane) crosspolymer, polymethyl methacrylate, lauroyl lysine, silk powder, cellulose powder, dispersants such as polyvalent metal salts of long-chain fatty acids, and organic powders such as various wax powders.

[0049] The proportion of the powder component in the raw material composition is preferably 0.01% by mass or more, more preferably 0.1% by mass or more, even more preferably 1% by mass or more, even more preferably 3% by mass or more, and even more preferably 5% by mass or more. The proportion of the powder component in the raw material composition is preferably 60% by mass or less, more preferably 50% by mass or less, even more preferably 45% by mass or less, even more preferably 30% by mass or less, and even more preferably 20% by mass or less. In particular, the proportion of the powder component in the raw material composition is preferably 0.01% by mass or more and 60% by mass or less, more preferably 0.1% by mass or more and 50% by mass or less, even more preferably 1% by mass or more and 45% by mass or less, even more preferably 3% by mass or more and 30% by mass or less, and even more preferably 5% by mass or more and 25% by mass or less.

[0050] The hardness of the core is one of the factors that affect the feeling of use of solid particles. From this viewpoint, the hardness of the raw material composition is preferably 500g or less, more preferably 350g or less, even more preferably 250g or less, and even more preferably 150g or less. On the other hand, by making the hardness of the raw material composition preferably 0.5g or more, more preferably 5g or more, and even more preferably 15g or more, it is possible to suppress unintended bonding of the raw material composition with other substances. From these viewpoints, the hardness of the raw material composition is preferably 0.5g or more and 500g or less, more preferably 5g or more and 350g or less, even more preferably 15g or more and 250g or less, and even more preferably 15g or more and 150g or less. The hardness of the raw material composition is measured by the method described in the Examples.

[0051] 〔powder〕 The ratio of the powder used in step 3 to the mass of solid particles (powder adhesion rate) is preferably 4.0% by mass or more, more preferably 4.5% by mass or more, even more preferably 5.0% by mass or more, and even more preferably 6.0% by mass or more, from the viewpoints of adhesion resistance and transport resistance. Also, from the viewpoint of not affecting the feeling of use, it is preferably 30% by mass or less, more preferably 20% by mass or less, even more preferably 15% by mass or less, even more preferably 13% by mass or less, and even more preferably 12% by mass or less.

[0052] The powder may be the same as those generally used in cosmetics without any particular limitation, and may be an inorganic powder, and the inorganic powder may be a pigment or an organic powder. Although an inorganic powder and an organic powder may be used in combination, it is preferable to contain an inorganic powder, and silica is more preferable. Specifically, the same powder components as those contained in the above-mentioned raw material composition can be used.

[0053] The powder to be used is preferably one having a size that effectively prevents the solid particles, which are the object of the manufacturing method of the present invention, from adhering to other objects during the manufacturing process. For example, the size of the particles constituting the powder can be determined by measuring the volume cumulative particle size D at 50% cumulative volume by a laser diffraction scattering type particle size distribution measurement method. 50 When expressed as D50 is preferably 0.01 μm or more, more preferably 0.1 μm or more, even more preferably 1 μm or more, even more preferably 5 μm or more, and even more preferably 10 μm or more. By using powder of this size, the powder removal operation can be easily performed. 50 is preferably 500 μm or less, more preferably 300 μm or less, even more preferably 160 μm or less, even more preferably 100 μm or less, and even more preferably 30 μm or less. By using powder with this size, the powder can be easily attached to the surface of the granular raw material. In particular, D 50 is preferably 0.01 μm or more and 500 μm or less, more preferably 0.1 μm or more and 300 μm or less, even more preferably 1 μm or more and 160 μm or less, even more preferably 5 μm or more and 100 μm or less, and even more preferably 10 μm or more and 30 μm or less.

[0054] From the viewpoint of effectively preventing adhesion to other objects during the production process of solid particles, the oil absorption of the powder is preferably 5 mL / 100 g or more, more preferably 15 mL / 100 g or more, and even more preferably 20 mL / 100 g or more. Also, from the viewpoint of preventing the oily components contained in the granular raw material from being excessively absorbed by the powder, the oil absorption of the powder is preferably 500 mL / 100 g or less, more preferably 400 mL / 100 g or less, and even more preferably 350 mL / 100 g or less. The oil absorption is measured in accordance with JIS K5101-13-1:2004.

[0055] The amount of powder in the solid particles can be determined and measured by various methods. For example, when the powder is inorganic, it can be quantified by burning the organic matter in the solid particles and measuring the residual ratio using a thermogravimetric and differential thermal analyzer as shown below. The amount of inorganic powder is measured by the method described in the examples.

[0056] If the powder is organic, all the components of the solid particles are dissolved in a solvent to prepare a sample. 1 The amount of powder attached to the core can be quantified by measurements such as H-NMR and laser desorption ionization mass spectrometry (LDI-MS).

[0057] The solid particles produced by the production method of the present invention are preferably used as cosmetics. For example, they can be used in a makeup method in which the solid particles are crushed and applied to the human body for beauty purposes. Specifically, the solid particles can be placed on a cosmetics palette, crushed with a makeup brush, and then applied to the lips using the makeup brush like lipstick. Alternatively, the solid particles can be crushed on the back of the hand and applied to the cheek with the fingers like blush or concealer. Alternatively, the solid particles can be crushed on the back of the hand and applied to the fingers or the back of the hand with the fingers like hand cream. Furthermore, the solid particles can be crushed by hand and used like oil cleansing. Furthermore, the solid particles can be crushed by hand or a tool and applied to the hair, and used like a treatment or hair wax.

[0058] Although the present invention has been described based on the preferred embodiment, the present invention is not limited to the above embodiment. EXAMPLES

[0059] The present invention will be described in more detail below with reference to examples, but the scope of the present invention is not limited to these examples. [Preparation of raw material composition] The compositions of the lipstick raw material compositions are shown in Table 1 below, and the compositions of the eyeshadow raw material compositions are shown in Table 2 below. For both raw material compositions, the base raw material was heated and dissolved at 110°C for 30 minutes, and then uniformly mixed using a disperser. Next, a color pigment, a glittering pigment, and an extender pigment, or a color pigment, a glittering pigment, and a dispersant, were added to the base raw material, and the mixture was uniformly mixed for another 15 minutes. After degassing, the mixture was allowed to solidify by natural cooling to prepare the raw material compositions. The melting points of the prepared raw material compositions were measured according to the general test method for raw materials for quasi-drugs, and were found to be 68°C for the lipstick raw material composition and 81°C for the eyeshadow raw material composition.

[0060] The lipstick raw material composition prepared above was heated and melted at 115°C and filled into a resin ointment bottle (diameter 30 mm, height 14 mm) to a height of 10 mm, then cooled and solidified at 20°C for 2 hours. After leaving to stand at 30°C for at least 6 hours, the hardness of the lipstick raw material composition was measured using a rheometer manufactured by Rheotec Corporation by reading the maximum load when a jig with a diameter of φ2 mm was inserted to a depth of 2 mm at a table speed of 2 mm / s. The hardness of the lipstick raw material composition was 35 g. When the eye shadow raw material composition prepared above was measured under the same conditions, the hardness was 41 g.

[0061] [Table 1]

[0062] [Table 2]

[0063] As shown in Table 1, the amount of oily components in the lipstick raw material composition was 89.4% by mass, which is the amount of components shown as base materials, and the amount of powdery components was 10.6% by mass, which is the total amount of color pigments, luster pigments, and extender pigments. In addition, the amount of oily components in the lipstick raw material composition with a melting point above 20°C (solid at 20°C) was 8% by mass, which is the total amount of paraffin, polyethylene wax, and microcrystalline wax, and the amount of oily components with a melting point of 20°C or lower (liquid at 20°C or lower) was 81.4% by mass, which is the total amount of other components. As shown in Table 2, the amount of oily components in the eye shadow raw material composition was 79.45% by mass, which is the amount of the components shown as the base material, and the amount of powdery components was 20.55% by mass, which is the total amount of color pigments, glittering pigments, and dispersants. The amount of oily components in the eye shadow raw material composition having a melting point of more than 20°C (solid at 20°C) was 9.0% by mass, which is the total amount of paraffin, synthetic wax, and microcrystalline wax, and the amount of oily components having a melting point of 20°C or lower (liquid at 20°C or lower) was 70.45% by mass, which is the total amount of other components.

[0064] [Measurement of maximum extension length of raw material composition when granulated] The lipstick raw material composition and eye shadow raw material composition prepared according to Tables 1 and 2 were discharged from the nozzle 12 at the dripping temperature and dripping flow rate shown in Table 3 and granulated, and the maximum length of extension of each raw material composition dripping from the nozzle 12 was measured. The maximum extension length was observed using a high-speed camera (chronos 1.4 manufactured by Kron Technologies, frame rate: 500 fps) and was taken as the distance from the tip of the nozzle 12 to the bottom end of the base particle in the frame immediately before each extended raw material composition was cut at any point. The maximum extension length was measured three times for each, and the average was 13.8 mm for the lipstick raw material composition and 17.1 mm for the eye shadow raw material composition.

[0065] [Example 1] Steps 1 and 2 (production of granular raw materials) A plurality of granular raw materials 13 were formed from the lipstick raw material composition using the device shown in Fig. 3. That is, lipstick raw material composition 10, which had been given fluidity by heating and melting the raw material composition at 90°C, was pumped at 5.2 mL / min using pump 11 and discharged from the tip of nozzle 12 having an inner diameter of 2.0 mm and an outer diameter of 3.2 mm at the dropping temperature and dropping distance shown in Table 3, thereby forming granular raw material 13 as droplets. The dropping distance is the distance between the tip of nozzle 12 and the outermost surface of the layer of powder 15, and the dropping temperature is the temperature of raw material composition 10 when it is discharged from nozzle 12.

[0066] Step 3 (Dropping granular raw material onto powder and coating with powder) The granular raw material 13 formed above was supplied with powder 15 at a temperature of 25°C to a thickness of 10 mm using a vibrating feeder 23 (a small electromagnetic feeder CF-2 manufactured by Symphonia Technology Co., Ltd.) equipped with a vibrating device 22 and a trough 21, which was vibrated with an amplitude of 0.663 mm and a frequency of 54.0 Hz.The powder 15 was then dropped onto the trough 21, placed on the trough 21, at a distance 5.5 times the maximum length that the raw material composition extends when granulated, and the granular raw material 13 and powder 15 were brought into contact with each other, thereby adhering the powder 15 to the surface of the granular raw material 13. The powder 15 has an average particle size D 50 The spherical silica used had a diameter of 15 μm and an oil absorption of 150 mL / 100 g. As a result, the powder 15 was attached to the surface of the target granular raw material 13, thereby obtaining solid particles 1 for lipstick in which the granular raw material 13 was covered with the powder 15. The amplitude value was measured using a laser displacement meter (Keyence LK-G5000) at the amplitude directly above the vibration device 22 on the top surface of the trough 21. The measurement conditions were diffuse reflection mode, sampling period 200 μs (5 kHz), and moving average 4.

[0067] (Powder removal and cooling) Thereafter, the powder 15 and the solid particles 1 were separated using a sieve 24 with 2,000 μm openings at room temperature (25° C.) to remove the powder 15 that was not attached to the solid particles 1. The mixture was naturally cooled on the sieve 24 for one minute or more, and the solid particles 1 were collected.

[0068] [Evaluation of solid particles 1] Ten solid particles 1 were randomly selected from the obtained solid particles 1 (excluding particles with fine particles 14 attached) and evaluated, and the average mass was 20.8 mg, the average diameter was 4.1 mm, the average height was 2.8 mm, and the average powder adhesion rate was 9.8 mass%.

[0069] <Powder adhesion rate> The amount (adhesion rate) of silica used as powder 15 in solid particles 1 was determined as follows. Ten solid particles 1 were randomly selected, and each was heated from 25°C to 600°C at 10°C / min under an air supply of 200mL / min using a Hitachi High-Tech Science Corporation simultaneous differential thermal thermogravimetry analyzer TG-DTA EXSTAR 6200, and the mass of the residue after combustion was measured. The powder adhesion rate was calculated from the mass of the residue when the same treatment was performed using only the raw material composition of the same mass as that used to produce solid particles 1, using the following formula. The average of the powder adhesion rates of the ten solid particles 1 was taken as the average powder adhesion rate. (Powder adhesion rate (mass%))=(mass% of solid particles 1 remaining)-[(mass% of raw material composition remaining) / [100-(mass% of raw material composition remaining)]]×[100-(mass% of solid particles 1 remaining)]

[0070] <Fine particle adhesion rate> From the obtained solid particles 1, 150 particles were randomly selected, and it was visually determined whether the surface of the granular raw material 13 was covered with powder 15 while the fine particles 14 were attached to the surface of the granular raw material 13. From all the extracted solid particles 1, solid particles 1-1 without fine particles attached (covered with powder 15 after coalescence of granular raw material 13 and fine particles 14) shown in Fig. 4 and solid particles 1-2 with fine particles attached (particles with fine particles 14 attached to the surface of granular raw material 13 covered with powder 15) shown in Fig. 5 were selected, and the fine particle attachment rate (%) was calculated by the following formula. The fine particle attachment rate of the solid particles of Example 1 was 7.6%. Fine particle adhesion rate (%) = (solid particle 1-2 (pieces) / solid particle 1 (pieces)) x 100

[0071] [Examples 2 and 3] Solid particles 1 for lipstick were produced in the same manner as in Example 1, except that the production conditions were changed as shown in Table 3. The obtained solid particles 1 were evaluated in the same manner as in Example 1, and the results are shown in Table 3.

[0072] [Examples 4 to 9] Solid particles 1 for eye shadow were produced in the same manner as in Example 1, except that the raw material composition was changed to an eye shadow raw material composition and the production conditions were changed as shown in Table 3. The obtained solid particles 1 were evaluated in the same manner as in Example 1, and the results are shown in Table 3.

[0073] [Comparative Examples 1 and 2] Solid particles 1 for lipstick were produced in the same manner as in Example 1, except that the conditions of the production method were changed as shown in Table 3. The obtained solid particles 1 were evaluated in the same manner as in Example 1, and the results are shown in Table 3. Note that under the production conditions of Comparative Example 2, the granular raw material could not be cut off from the liquid column, so that granular raw material 13 could not be produced, and solid particles 1 could not be produced.

[0074] [Table 3]

[0075] As shown in Table 3, according to the manufacturing methods of Examples 1 to 9, spherical solid particles 1 having a good appearance due to the coalescence of granular raw material 13 and fine particles 14 and then coating with powder 15 were obtained in high yield. On the other hand, the production method of Comparative Example 1 produced many solid particles with poor appearance due to fine particles adhering to the surface of the solid particles. As described above, according to the production method of the present invention, adhesion of fine particles to solid particles can be suppressed, and solid particles having good appearance can be obtained in high yield. [Explanation of symbols]

[0076] 1 solid particles 2 Solid particles with fine particles attached 3 Satellite particles 10. Fluidized raw material composition 11 Pump 12 Nozzles 13 Granular raw materials 14 Fine particles 15 Powder 16 Container 17 Mixer 21 Trough 22 Vibration device 23 Vibrating feeder 24 Sieve

Claims

1. A method for producing solid particles, comprising the following steps 1 to 3: Step 1: heating a raw material composition containing an oily component to impart fluidity; Step 2: A step of granulating the raw material composition having fluidity by discharging it to form a granular raw material; Step 3: dropping the granular raw material into a powder to coat the surface of the granular raw material with the powder; In the step 2, the raw material composition is discharged in advance, a maximum length that the raw material composition extends during granulation is measured, and a ratio of a dripping distance of the granular raw material to the maximum length that the raw material composition extends during granulation is set to be greater than 0 and not greater than 9.

2. The method for producing solid particles according to claim 1 , wherein the powder comprises silica.

3. The method for producing solid particles according to claim 1 or 2, further comprising a cooling step.

4. The method for producing solid particles according to claim 1 or 2, further comprising a step of removing the unattached powder.

5. The method for producing solid particles according to claim 1 or 2, wherein the granular raw material in step 2 is formed by heating the raw material composition to a temperature equal to or higher than the melting point of the raw material composition.

6. Average particle size D of the powder ５０ The method for producing solid particles according to claim 1 or 2, wherein the particle size is 0.01 μm or more and 500 μm or less.

7. The method for producing solid particles according to claim 1 or 2, wherein the average mass per particle of the obtained solid particles is 1 mg or more and 10,000 mg or less.

8. The method for producing solid particles according to claim 1 or 2, wherein the step of coating the surfaces of the granular raw material with the powder is carried out in a state where the powder is vibrated.

9. 9. The method for producing solid particles according to claim 8, wherein the vibration has an amplitude of 0.3 mm or more and a frequency of 30 Hz or more.

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