Method for producing seamless capsule

Abstract

The method for manufacturing the seamless capsule (50) includes a forming step of dripping a liquid droplet from a tip (1a) of a nozzle (1) to a cooling liquid (49) in a flow path forming a tube (10), and forming a seamless wet capsule (50w) from the liquid droplet. The nozzle (1) is provided with an inclined part (25) which inclines towards the inner side of the nozzle (1) from the midway of the nozzle (1) to the tail end (1a). The distance (Z) between the upper end (10a) of the forming pipe (10) and the apex (27) of a space surrounded by an imaginary plane (26) formed by extending the outer surface (25a) of the inclined part (25) toward the lower side of the tail end (1a) is within the range of-10 mm < = Z < = 6 mm. At Zlt; in the case of zero, the apex (27) is located below the upper end (10a) of the forming tube (10). At Zgt; in the case of zero, the apex (27) is positioned above the upper end (10a) of the forming tube (10).

Description

Technical Field

[0001] This invention relates to a method for manufacturing seamless capsules. Background Technology

[0002] Patent Document 1 discloses a method for manufacturing a seamless spherical capsule formed by covering a filling material with a film material. In this method, droplets are allowed to flow downwards from the end of a nozzle into a coolant (hardening liquid) within a flow path of a forming tube. The nozzle tapers from its middle section towards its end. At the end of the nozzle, an end face with an opening for droplet flow is provided. The end face is orthogonal to the central axis of the nozzle and faces horizontally. Furthermore, for this manufacturing method, a so-called air-nozzle method is applicable, in which the end face of the nozzle is positioned above the surface of the coolant. When the outer diameter of the manufactured seamless capsule is d, the distance between the end face of the nozzle and the liquid surface is set in the range of 0.5d to 3d.

[0003] Prior art literature Patent documents Patent document 1: Japanese Patent Application Publication No. 2002-136576. Summary of the Invention

[0004] The problem that the invention aims to solve However, there is still room for improvement in the manufacturing method of seamless capsules, particularly in the stable production of high-quality, seamless capsules, such as capsules without membrane rupture.

[0005] The objective of this invention is to stably manufacture high-quality seamless capsules.

[0006] Solution for solving the problem One aspect of the present invention provides a method for manufacturing a seamless capsule, which includes a step of dripping a droplet from the end of a nozzle into a flow path of a forming tube to form a coolant, and forming a seamless wet capsule from the droplet. The nozzle has an inclined portion that slopes inward toward the end of the nozzle from its middle. The distance Z between the vertex of the space surrounded by an imaginary surface formed by extending the outer surface of the inclined portion toward the lower end of the nozzle and the upper end of the forming tube is in the range of -10 mm ≤ Z ≤ 6 mm. When Z < 0, the vertex is located lower than the upper end of the forming tube, and when Z > 0, the vertex is located higher than the upper end of the forming tube.

[0007] The effects of the invention According to the present invention, high-quality seamless capsules can be manufactured stably. Attached Figure Description

[0008] Figure 1This is a schematic diagram of a manufacturing apparatus for implementing the method of manufacturing a seamless capsule according to the embodiments.

[0009] Figure 2 It is Figure 1 The diagram shows an enlarged view of the nozzle and forming tube of the manufacturing apparatus.

[0010] Figure 3 It is along Figure 2 The horizontal cross-sectional view of the nozzle is shown by line III-III.

[0011] Figure 4 This diagram illustrates the distance between the imaginary apex of the nozzle and the upper end of the forming tube.

[0012] Figure 5 The figure shows an enlarged view of the nozzle and forming tube involved in the first modified example.

[0013] Figure 6A This is a horizontal cross-sectional view of the nozzle involved in the second variation.

[0014] Figure 6B This is a horizontal cross-sectional view of the nozzle involved in the third variation.

[0015] Figure 7 This is the front view of the nozzle involved in the fourth variation.

[0016] Figure 8A This is the front view of the nozzle involved in the fifth variation.

[0017] Figure 8B This is the front view of the nozzle involved in the sixth variation. Detailed Implementation

[0018] Hereinafter, embodiments will be described with reference to the accompanying drawings. Furthermore, the same or corresponding elements are labeled with the same reference numerals in all figures, and repetition of detailed descriptions is omitted.

[0019] Figure 1 The manufacturing apparatus shown manufactures a seamless capsule 50 using the manufacturing method described in this embodiment. The manufacturing apparatus includes a nozzle 1, a contents tank 2, a contents supply pipe 2a, a film liquid tank 3, a film liquid supply pipe 3a, a coolant reservoir 6, a coolant tank 7, a coolant supply pipe 8, a cooling device 9, a forming pipe 10, pumps 11 to 13, a screen 14, and a dryer 15.

[0020] Nozzle 1 is connected to content fluid tank 2 via content fluid supply pipe 2a and to film fluid tank 3 via film fluid supply pipe 3a. Content fluid tank 2 stores content fluid 41. Content fluid 41 is pumped from content fluid tank 2 to nozzle 1 via content fluid supply pipe 2a by pump 11. Content fluid 41 is also referred to as filling fluid, and if it is filled into the interior of seamless capsule 50, it becomes content 51, described later. Film fluid tank 3 stores film fluid 42. Film fluid 42 is pumped from film fluid tank 3 to nozzle 1 via film fluid supply pipe 3a by pump 12.

[0021] Reference Figure 1 and Figure 2 The coolant reservoir 6 is connected to the coolant tank 7 via a coolant supply pipe 8. The coolant tank 7 stores coolant 49. Coolant 49 is also referred to as a solidified liquid or curing liquid. The coolant 49 is pumped from the coolant tank 7 to the coolant reservoir 6 via the coolant supply pipe 8 by a pump 13, and is cooled by the cooling device 9 in the process. The coolant 49 is contained within the internal space of the coolant reservoir 6. With a portion of the nozzle 1 (the inclined portion 25 described later) and the upper end of the forming pipe 25 positioned within the internal space of the coolant reservoir 6, the coolant 49 flowing into the forming pipe 10 is stored within the internal space. The coolant reservoir 6 has a hollow structure, and the inner surface of the coolant reservoir 6 defines the internal space. Specifically, the coolant reservoir 6 has a bottom wall 6a, an upper wall 6b, and a peripheral wall 6c, which define the internal space. The bottom wall 6a and the upper wall 6b are substantially horizontal and separated from each other in the vertical direction. The peripheral wall 6c is erected vertically upwards from the periphery of the bottom wall 6a. The periphery of the upper wall 6b is located above the peripheral wall 6c, and a spacer 6e is provided between the periphery of the upper wall 6b and the upper end of the peripheral wall 6c. The spacer 6e is a component that determines the distance between the upper wall 6b and the peripheral wall 6c and is replaceable. The coolant reservoir 6 is provided with a coolant inlet port 6d for allowing coolant 49 to flow into the internal space. The downstream end of the coolant supply pipe 8 is connected to the coolant inlet port 6d. The upper wall 6b is configured such that the space above the surface 49L of the coolant 49 is open to the atmosphere. The coolant 49 returns from the coolant reservoir 6 to the coolant tank 7 via a forming pipe 10. The forming pipe 10 is open at both ends, forming a flow path for the coolant 49 to circulate. Figure 1 and Figure 2 In the example, coolant 49 flows through the flow path of forming pipe 10 under water head pressure. In a variation of this embodiment, the pump 13 can also be used to make coolant 49 flow through the flow path of forming pipe 10. In such a variation, a coolant reservoir 6 with its internal space sealed can be used.

[0022] The spacer 6e only needs to be able to separate the upper wall 6b from the peripheral wall 6c, and the material or shape of the spacer 6e can be arbitrarily selected according to the purpose of manufacturing. Examples of materials for the spacer 6e include resin, metal, natural rubber, or synthetic rubber. In a top view viewed vertically, the shape of the spacer 6e can be an integral shape covering the portion of the peripheral edge of the upper wall 6b facing the peripheral wall 6c, or a discontinuous shape covering a portion of the portion facing the peripheral wall 6c.

[0023] The upper end 10a (upstream end) of the forming tube 10 opens into the internal space of the coolant reservoir 6. The central axis of the forming tube 10 is vertically oriented at its upper end, while the upper end 10a is horizontal. The cross-section of the forming tube 10 is typically circular. The forming tube 10 extends downward from its upper end 10a, penetrates the bottom wall 6a of the coolant reservoir 6, briefly bends upward, then bends downward again, and terminates. Furthermore, the distance H between the upper end 10a and the inner surface of the bottom wall 6a can be varied. A seal 6f is provided between the forming tube 10 and the bottom wall 6a to prevent the coolant 49 from flowing out. The opening at the other end (downstream end) of the forming tube 10 is located above the coolant tank 7 and faces downward. Coolant 49 is released from the opening at the other end of the forming tube 10 and contained in the coolant tank 7. The upper end of the forming tube 10 is the portion of the forming tube 10 that protrudes upward from the lower inner surface of the inner surface of the coolant tank 7, which defines the internal space. The lower inner surface of the coolant tank 7 is the inner surface of the bottom wall 6a.

[0024] The seal 6f only needs to prevent the coolant 49 from leaking out, and the material of the seal 6f can be arbitrarily selected according to the purpose of manufacturing. Examples of materials for the seal 6f include resin, metal, natural rubber, or synthetic rubber.

[0025] Reference Figure 2 The nozzle 1 is cylindrical as a whole. The central axis A of the nozzle 1 faces vertically. At the middle part of the nozzle 1 in the axial direction, there is a plate-shaped flange 1b that protrudes in the radial direction. The flange 1b is supported on the outer surface (upper surface) of the upper wall 6b of the coolant reservoir 6. The nozzle 1 protrudes upward from the upper wall 6b at its axial base end side. At this base end side, there is a content liquid inflow port 1c for the content liquid 41 to flow into the nozzle 1 and a film liquid inflow port 1d for the film liquid 42 to flow into the nozzle 1. The nozzle 1 passes through the upper wall 6b from above and enters the internal space of the coolant reservoir 6 at its axial end side.

[0026] The flange 1b is a component fixed to the nozzle 1 and is replaceable. When fixing the flange 1b to the nozzle 1, screws or other fasteners can be used. As described above, the flange 1b is supported on the upper surface of the upper wall 6b, thus the position of the nozzle 1 can be adjusted by utilizing the thickness of the flange 1b in the vertical direction. The material of the flange 1b can be arbitrarily selected according to the manufacturing purpose. Examples of materials for the flange 1b include resin, metal, natural rubber, or synthetic rubber. Furthermore, the shape of the flange 1b is not particularly limited as long as it allows the nozzle 1 to be mounted on the upper wall 6b; for example, it can be circular, elliptical, or polygonal when viewed from above in the vertical direction.

[0027] Inside the coolant reservoir 6, the coolant level 49L is located between the upper end 10a of the forming tube 10 and the inner surface (lower surface) of the upper wall 6b. The position of the coolant level 49L can be controlled in this way by adjusting the flow rate of the pump 13. The end 1a of the nozzle 1 is located below the coolant level 49L. That is, the end of the nozzle 1 is immersed in the coolant 49 contained in the coolant reservoir 6.

[0028] Reference Figure 2 and Figure 3 The nozzle 1 has a central nozzle 21 and an outermost nozzle 22. Both the central nozzle 21 and the outermost nozzle 22 extend axially inside the nozzle 1. The central nozzle 21 has a circular cross-section centered on the central axis A. The outermost nozzle 22 is concentric with the central nozzle 21, surrounding it from the outside, and has an annular cross-section centered on the central axis A. One end (upper end, upstream end) of the central nozzle 21 is connected to the inner liquid inlet port 1c. One end (upper end, upstream end) of the outermost nozzle 22 is connected to the film liquid inlet port 1d. The other ends (lower end, downstream end) of the central nozzle 21 and the outermost nozzle 22 open at the end 1a of the nozzle 1. The end 1a of the nozzle 1 forms a flat end face orthogonal to the central axis A. The central nozzle 21 and the outermost nozzle 22 open at this end face.

[0029] The nozzle 1 has an inclined portion 25 that slopes inward toward the end 1a from its middle section. The inclined portion 25 is located at the end side in the axial direction, which is closer to the flange portion 1b.

[0030] As from Figure 2 and Figure 4As can be seen, in the vertical section of the nozzle 1 passing through the central axis A of the nozzle 1, the outer surface 25a of the inclined portion 25 is represented by a pair of straight lines 25b. The pair of straight lines 25b connects the upper end 25c and the lower end 25d of the outer surface 25a of the inclined portion 25. The pair of straight lines 25b are inclined in a manner that they approach each other towards the end 1a. The pair of straight lines 25b are linearly symmetrical about the central axis A. The lower ends of the pair of straight lines 25b are respectively connected to the end faces represented by horizontal lines perpendicular to the central axis A. (As from...) Figure 3 As can be seen, in this embodiment, the outer surface of the inclined portion 25 is circular in the horizontal cross-section of the nozzle 1 through the central axis A of the nozzle 1.

[0031] Thus, in this embodiment, the inclined portion 25 is shaped like a frustum of a cone. A pair of straight lines 25b are the generatrices of the frustum of a cone.

[0032] Here, refer to Figure 4 Imagine an imaginary surface 26 formed by extending the outer surface 25a of the inclined portion 25 downward toward the end 1a of the nozzle 1. The imaginary surface 26, in a vertical cross-section passing through the central axis A of the nozzle 1, is represented by the downward extensions of a pair of straight lines 25b. The imaginary surface 26 becomes a point on the central axis A. That is, the downward extensions of the pair of straight lines 25b intersect on the central axis A. This intersection point is the vertex 27 of the space enclosed by the imaginary surface 26. In this embodiment, where the cross-section of the outer surface 25a of the inclined portion 25 is circular, this imaginary space is conical with the end face of the nozzle 1, where the central nozzle 21 and the outermost nozzle 22 open, as its base.

[0033] The distance Z between vertex 27 and the upper end 10a of forming tube 10 is within the range of -10 mm ≤ Z ≤ 6 mm. Distance Z refers to the interval between vertex 27 and the upper end 10a in the vertical direction, which corresponds to the orthogonal direction of the axial direction of nozzle 1, the normal direction of the end face of nozzle 1, the axial direction of forming tube 10, and the opening of the upper end 10a of forming tube 10. When vertex 27 coincides with the upper end 10a of forming tube 10, Z = 0. When Z < 0, vertex 27 is located lower than the upper end 10a of forming tube 10, i.e., within the flow path of forming tube 10. When Z > 0, vertex 27 is located higher than the upper end 10a of forming tube 10, i.e., outside the forming tube 10. Furthermore, Figure 4 The case where Z < 0 is illustrated, and further, the case where Z < 0, but the end 1a of nozzle 1 is located higher than the upper end 10a of forming tube 10 is shown. However, this is merely an example.

[0034] In this embodiment, the distance Z only needs to be within the range of -10 mm ≤ Z ≤ 6 mm. However, the distance Z can also be less than 5 mm, less than 4 mm, less than 3.5 mm, less than 3.2 mm, less than 3 mm, less than 2 mm, less than 1 mm, less than 0.5 mm, or less than 0 mm. Alternatively, the distance Z can also be greater than -9.7 mm, greater than -9 mm, greater than -8 mm, greater than -7 mm, greater than -6 mm, or greater than -5 mm.

[0035] When the distance Z between the vertex 27 and the upper end 10a of the forming tube 10 is set, in this embodiment, the thickness of the spacer 6e, the thickness of the flange 1b, and the distance H between the upper end 10a and the inner surface of the bottom wall 6a can be changed, but these three changes are not necessary. That is, changing at least one of the thickness of the spacer 6e, the thickness of the flange 1b, and the distance H between the upper end 10a and the inner surface of the bottom wall 6a is sufficient. In other words, at least one of the nozzle 1, the upper wall 6b, and the forming tube 10 can be configured in a way that allows it to move up and down along the central axis A of the nozzle 1.

[0036] Furthermore, in the vertical section of the nozzle 1 passing through the central axis A of the nozzle 1, the angle θ between the pair of straight lines 25b that connect the upper end 25c and the lower end 25d of the outer surface 25a of the inclined portion 25 is in the range of 20° to 70°.

[0037] Reference Figure 1 and Figure 2 The method for manufacturing a seamless capsule 50 using such a manufacturing apparatus includes a formation step in which droplets are dripped from the end 1a of a nozzle 1 into a flow path of a forming tube 10 containing a coolant 49, thereby forming a seamless wet capsule 50w from the droplets. In this formation step, the end 1a of the nozzle 1 is located below the surface 49L of the coolant 49. That is, the so-called submerged method is applied to the manufacturing apparatus and method according to this embodiment.

[0038] The droplet dripping from nozzle 1 comprises: a content liquid 41 supplied from a content liquid tank 2 to nozzle 1 and ejected from a central nozzle 21; and a coating liquid 42 supplied from a coating liquid tank 3 to nozzle 1 and ejected from an outermost nozzle 22. The content liquid 41 is ejected downward from the center of the end face. The coating liquid 42 is ejected downward from the periphery of the end face, covering the content liquid 41 from the outer periphery. Thus, nozzle 1 ejects a composite jet 59 containing the content liquid 41 and the coating liquid 42 downward into coolant 49 from its end face. The composite jet 59 extends downward from the end face in coolant 49. The composite jet 59 is dropletized from its lower end by surface tension. If the droplet becomes a particle of a predetermined size and the coating liquid 42 completely covers the content liquid 41, the coating liquid 42 solidifies. Thus, a seamless capsule 50 is formed.

[0039] The seamless capsule 50 is spherical in shape as a whole, and has contents 51 and a membrane layer 52 that encloses the contents 51. The membrane layer 52 is formed by the coagulation of the membrane liquid 42 and has no seams. The contents 51 are composed of the contents liquid 41, but the contents 51 can also be in the state of liquid, semi-solid such as gel, or solid.

[0040] A composite jet 59 is ejected into the flow path of the forming tube 10, where seamless capsules 50 are formed. The formed seamless capsules 50 are carried along the forming tube 10 by the flow of coolant 49 within it. The upper opening of the coolant tank 7 is covered by a screen 14. The screen 14 allows coolant 49 from the outlet at the other end of the forming tube 10 to pass through, while preventing the seamless capsules 50 from flowing into the coolant tank 7. Seamless capsules 50 blocked by the screen 14 are recovered as wet capsules 50w.

[0041] The recovered wet capsules 50w can also be the final product. The manufacturing apparatus can also include a dryer 15 for drying the wet capsules 50w. By implementing a drying process using the dryer 15 to dry the wet capsules 50w, dry capsules 50d can be obtained. Thus, it is also possible for the wet capsules 50w to be an intermediate product of the dry capsules 50d, and for the dry capsules 50d to be the final product.

[0042] The content liquid 41 is not particularly limited and may include lipophilic or hydrophilic liquids, suspensions of such liquids with powders insoluble in such liquids, or mixtures of such liquids. Excipients, stabilizers, surfactants, auxiliaries, or foaming agents may also be appropriately incorporated into the content liquid 41.

[0043] The film-forming liquid 42 contains natural polymers and water. The natural polymers are the components that cause the film-forming liquid 42 to solidify, and are mostly water-soluble. The natural polymers are, for example, at least one selected from the group consisting of gelatin, casein, zein, pectin or its derivatives, alginate or its salts, agar, gellan gum, carrageenan, red algae gum, chitosan, cardan gum, starch, modified starch, pullulan, and mannan. The natural polymers are not limited to the above-mentioned components; any component capable of forming the film layer 52 can be used.

[0044] The film-forming liquid 42 may also contain a plasticizer. The plasticizer is a component that imparts flexibility to the film layer 52. Specifically, the plasticizer is designed to maintain sufficient flexibility in the dried material of the film layer 52 after 50 days of drying and to prevent cracking. Examples of plasticizers include glycerin and sorbitol. Any plasticizer is acceptable as long as it imparts flexibility to the film layer 52, and is not limited to the above-mentioned components.

[0045] The film liquid 42 may also contain additives such as pigments, flavoring ingredients, preservatives or fragrances, corresponding to the purpose of the seamless capsule 50.

[0046] The viscosity of the film-forming liquid 42 is preferably 30 to 350 mPa·s at 60 °C, more preferably 50 to 300 mPa·s, and even more preferably 50 to 250 mPa·s. The viscosity of the film-forming liquid 42 within the above range enables efficient production of seamless capsules based on the droplet method.

[0047] The coolant 49 is typically below 20°C, preferably 1 to 18°C. Furthermore, the temperature of the liquids ejected from the nozzle 1 is not particularly limited, but is typically 15 to 70°C, preferably 20 to 65°C.

[0048] For coolant 49, oily components such as medium-chain triglycerides (MCT), vegetable oils (coconut oil, sunflower oil, safflower oil, sesame oil, rapeseed oil, grapeseed oil, and mixtures thereof), liquid paraffin, and mixtures thereof can be used.

[0049] Reference Figure 2Coolant 49 flows from the liquid surface 49L towards the opening at the upper end 10a of the forming tube 10 within the coolant reservoir 6. The inclined portion 25 of the nozzle 1 is positioned near this opening, and the coolant 49 flows along the outer surface of the inclined portion 25 towards the opening of the forming tube 10. The flow along the outer surface continues further into the lower forming tube 10 from the end 1a of the nozzle 1, towards the radially inward side of the nozzle 1. In other words, the coolant 49 flows along an imaginary surface 26 extending downward from the outer surface of the inclined portion 25, towards the apex 27 of the space surrounded by this imaginary surface 26. Sometimes, vortices of coolant 49 form near this apex 27. If such vortices occur, the shape of the composite jet 59 flowing from the nozzle 1 becomes unstable.

[0050] If the apex 27 moves excessively upwards from the upper end 10a, turbulence may occur in the flow of coolant 49 near the opening of the forming tube 10, differing from the apex 27. This turbulence affects the composite jet 59, hindering the stable formation of the film layer 52, making it prone to rupture, and increasing the deviation in the particle size of the wet capsules 50w. If the apex 27 extends excessively into the forming tube 10, controlling the flow rate of coolant 49 becomes difficult as it passes through the narrow space surrounded by the forming tube 10 and the nozzle 1. Therefore, the shear force generated by the flow of coolant 49 as it flows through the forming tube 10 becomes unstable, and the deviation in the particle size of the wet capsules 50w easily increases.

[0051] In contrast, in this embodiment, the distance Z between the vertex 27 and the upper end 10a of the forming tube 10 is within the range of -10 mm ≤ Z ≤ 6 mm. Thus, by adjusting the position of this hypothetical vertex 27 instead of the end face of the nozzle 1, the flow of coolant 49 into the forming tube 10 can be easily controlled using the inclined portion 25, resulting in the stable formation of the film layer 52 and reducing the particle size deviation of the wet capsule 50w. Therefore, it is possible to manufacture a high-quality seamless capsule 50 with suppressed film rupture.

[0052] If the angle θ between the two straight lines 25b connecting the upper end 25c and lower end 25d of the outer surface 25a of the inclined portion 25 is small, the position of the vertex 27 moves downward from the end face. As a result, the flow of coolant 49 is prone to turbulence near the lower end of the composite jet 59, and the deviation in the particle size of the generated seamless capsule 50 tends to increase. On the other hand, if the angle θ is large, the position of the vertex 27 moves closer to the end face. Therefore, the composite jet 59 is easily affected by the vortex of coolant 49 immediately after being ejected. The shape of the composite jet 59 becomes unstable, and the particle size of the generated seamless capsule 50 becomes unstable. In this embodiment, the angle θ is in the range of 20° to 70°. Therefore, the particle size of the seamless capsule 50 is stable, and particle size deviation can be suppressed. The lower limit of angle θ is preferably 30° or more. Furthermore, the upper limit of angle θ is preferably 60° or less.

[0053] Through the above, the coefficient of variation of the particle size of the wet capsule 50w becomes less than 0.1. When dry capsules 50d are obtained from such wet capsules 50w, the coefficient of variation of the particle size of the dry capsules 50d becomes less than 0.1. Thus, high-quality seamless capsules 50 can be consistently manufactured. Furthermore, the coefficient of variation is a dimensionless statistical value obtained by dividing the standard deviation of multiple samples related to a certain indicator value by their mean.

[0054] The implementation method has been described so far, but the above configuration is merely an example and can be appropriately modified within the scope of the spirit of the present invention.

[0055] Figure 5 The first variation is shown. For example... Figure 5 As shown, a seamless capsule 50 with a three-layer structure can also be manufactured. In this case, the nozzle 1 also has an intermediate nozzle 23 formed radially between the central nozzle 21 and the outermost nozzle 22. The intermediate nozzle 23 is concentric with the central nozzle 21 and the outermost nozzle 22, has an annular cross-section, and extends axially. The upper end of the intermediate nozzle 23 is connected to an intermediate liquid inflow port 1e for the intermediate liquid 43 supplied from an intermediate liquid tank (not shown). The lower end of the intermediate nozzle 23 is open at its end face. The composite jet 59 contains the intermediate liquid 43 between the contents 41 and the film liquid 42. Through the dropletization of the composite jet 59, a seamless capsule 50 containing the contents 51, the intermediate layer 53, and the film layer 52 is generated within the forming tube 10.

[0056] Figure 6A The second variation is shown. Figure 6B The third variation is shown. The horizontal cross-section of the outer surface of the inclined portion 25 of the nozzle 1 is not limited to a circular shape. For example... Figure 6A As shown, the horizontal cross-section can also be an ellipse. For example... Figure 6B As shown, the horizontal cross-section can also be a polygon. Figure 6B In this example, the polygon is a square, but it can also be a quadrilateral other than a square. Furthermore, the number of angles or sides of a polygon is not limited to four.

[0057] Figure 7 The fourth variation is shown. The nozzle 1 may also consist of a cylindrical nozzle body 31 and a cap 32 covering the end of the nozzle body 31 (refer to the dotted line). The cap 32 has an inclined portion 25 and an end 1a, so that it can be attached and detached relative to the nozzle body 31. Multiple caps 32 with different angles θ may also be prepared for one nozzle body 31, and one cap 32 selected from the multiple caps 32 may be attached to the nozzle body 31. Thus, a cap 32 of appropriate size can be selected according to the content liquid and the film liquid.

[0058] Figure 8A The fifth variation is shown. Figure 8B The sixth variation is shown. In the vertical section of nozzle 1 passing through the central axis A of nozzle 1, in Figure 2 and Figure 7 In the example shown, the outline of the outer surface 25b of the inclined portion 25 is a straight line, but the outline is not limited to a single straight line. Figure 8A In the fifth variation, the outline of the outer surface 25b can also be a wavy line or a line similar to a wavy line. When the outline of the outer surface 25b is a wavy line or the like, the intersection point of the downward extensions of a pair of straight lines 25b on the central axis A and the vertex 27 of the space surrounded by the imaginary surface 26 may not be the same.

[0059] exist Figure 8B In the sixth variation, the outline of the outer surface 25b can also be a bend or a curve. When the outline of the outer surface 25b is a curve or the like, the main body of the inclined portion 25 is the part of the inclined portion 25 that is largely related to the control of the coolant flow, the straight line connecting the upper and lower ends of the outer surface of the main body is the straight line 25b, and the imaginary surface 26 is the imaginary surface formed by extending the outer surface of the inclined portion 25 downward.

[0060] Although detailed illustrations are omitted, the second or third modification can also be applied to the first modification, and the fourth modification can also be applied to the first modification. The second or third modification and the fourth modification can also be applied simultaneously to the above-described embodiments or the first modification. The second or third modification and the fifth or sixth modification can also be applied simultaneously to the above-described embodiments or the first modification.

[0061] The present invention will now be described in more detail through examples and comparative examples (experiments 1 to 28), but the invention is not limited thereto. Furthermore, in the following description, "parts" and "%" are used as mass standards unless otherwise specified.

[0062] (Experiment Category 1) The contents of 80 parts of MCT (manufactured by Kao) were prepared. A film-forming solution was prepared using 16 parts gelatin (manufactured by PB Leiner Argentina), 4 parts sorbitol (manufactured by Roquette China Co. Ltd.), and 300 parts purified water. The Bloom value of the gelatin was 240, and the viscosity of the film-forming solution was 50 mPa·s at 60 °C. A 100% coolant for MCT (manufactured by Kao) was prepared. The preparation of these liquids was the same in other experimental categories 2 to 28.

[0063] Use with such Figure 1 The seamless capsule manufacturing machine (manufactured by Morishita Jintan) illustrated here simultaneously dispenses the contents from a central nozzle and the film liquid from an outermost nozzle into a coolant, creating a seamless capsule with a two-layer structure. Next, the resulting seamless capsule is air-dried to evaporate the moisture contained in the film layer, yielding a dry capsule. The mass of the film layer is 30% of the total mass of the dry capsule. The method for manufacturing the dry capsule and the mass ratio of the film layer described here are the same in other experimental categories 2 to 28.

[0064] As shown in Table 1, a first nozzle (1-60) with an inclined portion is used as the nozzle having a central nozzle and an outermost nozzle. This first nozzle (1-60) is formed so that the particle size of the dry capsules to be generated is approximately 1 mm, and the angle between the outline of the inclined portion (hereinafter referred to as "angle θ") is 60°. Furthermore, in order to obtain the desired particle size, the flow rates of the inner liquid, the film liquid, and the coolant are adjusted by dividing the flow path cross-sectional area of ​​the forming tube as shown in Table 1.

[0065] The position of the nozzle relative to the forming tube is adjusted so that the distance between the apex of the space surrounded by the imaginary surface formed by extending the outer surface of the inclined portion and the upper end of the forming tube (hereinafter referred to as "distance Z") is -10.1 mm. The end of the nozzle is positioned lower than the surface of the coolant, and the composite jet is ejected into the coolant.

[0066] (Experiments 2 to 4) As shown in Table 1, in Experiment Classes 2 to 4, except for the point where the distance Z changes from Experiment Class 1, the first nozzle is used to generate seamless capsules, just like in Experiment Class 1.

[0067] In Experiment Class 2, the distance Z was adjusted to -1.8 mm. In Experiment Class 3, the distance Z was adjusted to 3.2 mm. In Experiment Class 4, the distance Z was adjusted to 13.2 mm.

[0068] (Experiments 5 to 8) As shown in Table 1, in experimental categories 5 to 8, a second nozzle (1-30) with an inclined section was used as the nozzle having a central nozzle and an outermost nozzle. This second nozzle (1-30), like the first nozzle (1-60), was shaped to produce dry capsules with a particle size of approximately 1 mm, and the angle θ was 30°. The flow rates of the inner liquid, the film liquid, and the coolant were adjusted by dividing the cross-sectional area of ​​the flow path of the forming tube as shown in Table 1.

[0069] In experiment category 5, the distance Z was adjusted to -14.9 mm. In experiment category 6, the distance Z was adjusted to -4.5 mm. In experiment category 7, the distance Z was adjusted to 0.5 mm. In experiment category 8, the distance Z was adjusted to 10.6 mm.

[0070] (Experiments 9 to 12) As shown in Table 2, in experimental categories 9 to 12, a third nozzle (5-60) with an inclined section was used as the nozzle having a central nozzle and an outermost nozzle. This third nozzle (5-60) was shaped to produce dry capsules with a particle size of approximately 5 mm, and the angle θ was 60°. The flow rates of the inner liquid, the film liquid, and the coolant were adjusted by dividing the cross-sectional area of ​​the flow path of the forming tube as shown in Table 2.

[0071] In experiment category 9, the distance Z was adjusted to -19 mm. In experiment category 10, the distance Z was adjusted to -5.7 mm. In experiment category 11, the distance Z was adjusted to -0.7 mm. In experiment category 12, the distance Z was adjusted to 9.3 mm.

[0072] (Experiments 13 to 16) As shown in Table 2, in experimental categories 13 to 16, a fourth nozzle (5-40) with an inclined section was used as the nozzle having a central nozzle and an outermost nozzle. This fourth nozzle (5-40), like the third nozzle (5-60), was shaped to produce dry capsules with a particle size of approximately 5 mm, and the angle θ was 40°. The flow rates of the inner liquid, the film liquid, and the coolant were adjusted by dividing the cross-sectional area of ​​the flow path of the forming tube as shown in Table 2.

[0073] In experiment category 13, the distance Z was adjusted to -30 mm. In experiment category 14, the distance Z was adjusted to -5.8 mm. In experiment category 15, the distance Z was adjusted to -0.8 mm. In experiment category 16, the distance Z was adjusted to 9.2 mm.

[0074] (Experiments 17 to 20) As shown in Table 2, in experimental categories 17 to 20, the fifth nozzle (5-30), which has a central nozzle and an outermost nozzle, is used as the nozzle with an inclined section. This fifth nozzle (5-30), like the third nozzle (5-60), is shaped to produce dry capsules with a particle size of approximately 5 mm, and the angle θ is 30°. The flow rates of the inner liquid, the film liquid, and the coolant are adjusted by dividing the cross-sectional area of ​​the flow path of the forming tube as shown in Table 2.

[0075] In experiment category 17, the distance Z was adjusted to -36.2 mm. In experiment category 18, the distance Z was adjusted to -6 mm. In experiment category 19, the distance Z was adjusted to -1 mm. In experiment category 20, the distance Z was adjusted to 9 mm.

[0076] (Experiments 21 to 24) As shown in Table 3, in experimental categories 21 to 24, a sixth nozzle (8-60) with an inclined section was used as the nozzle having a central nozzle and an outermost nozzle. This sixth nozzle (8-60) was shaped to produce dry capsules with a particle size of approximately 8 mm, and the angle θ was 60°. The flow rates of the inner liquid, the film liquid, and the coolant were adjusted by dividing the cross-sectional area of ​​the flow path of the forming tube as shown in Table 3.

[0077] In experiment category 21, the distance Z was adjusted to -26 mm. In experiment category 22, the distance Z was adjusted to -9.5 mm. In experiment category 23, the distance Z was adjusted to -4.5 mm. In experiment category 24, the distance Z was adjusted to 6.1 mm.

[0078] (Experiments 25 to 28) As shown in Table 3, in experimental categories 25 to 28, the seventh nozzle (8-30), which has a central nozzle and an outermost nozzle, was used as the nozzle with an inclined section. This seventh nozzle (8-30), like the sixth nozzle (8-60), was shaped to produce dry capsules with a particle size of approximately 8 mm, and the angle θ was 30°. The flow rates of the inner liquid, the film liquid, and the coolant were adjusted by dividing the cross-sectional area of ​​the flow path of the forming tube as shown in Table 3.

[0079] In experiment category 25, the distance Z was adjusted to -51 mm. In experiment category 26, the distance Z was adjusted to -9.7 mm. In experiment category 27, the distance Z was adjusted to -4.7 mm. In experiment category 28, the distance Z was adjusted to 5.3 mm.

[0080] (Example / Comparative Example) Experimental categories 2, 3, 6, 7, 10, 11, 14, 15, 18, 19, 22, 23, 26, and 27 are examples where the distance Z is within the range of -10.0 mm ≤ Z ≤ 6.0 mm. Other experimental categories 1, 4, 5, 8, 9, 12, 13, 16, 17, 20, 21, 24, 25, and 28 are comparative examples where the distance Z is outside this range.

[0081] (evaluate) The following evaluation was conducted using seamless capsules obtained through various experimental classifications.

[0082] <Mean particle size and coefficient of variation> In each of the experimental categories 1 to 28, 20 wet capsules were randomly selected, and the particle size (outer diameter) of each wet capsule was measured individually using calipers. The mean and standard deviation of the wet capsule particle size were calculated based on the 20 particle size data. Then, the coefficient of variation of the wet capsule particle size was calculated by dividing the standard deviation by the mean. The same method was used for dry capsules, calculating the mean, standard deviation, and coefficient of variation of the dry capsule particle size.

[0083] In this embodiment, the average particle size of the dry capsules is equal to or close to the desired particle size. Furthermore, in this embodiment, the coefficient of variation is less than 0.1 for both wet and dry capsules to suppress particle size deviation.

[0084] <Yield rate of wet capsules> In each of the experimental categories 1 to 28, 100 objects (approximately the same size as the wet capsule) formed by the composite jet ejected from the nozzle and flowing down in the forming tube were visually identified, and the number of fragments with ruptured membranes rather than spherical shapes was counted. The yield was then calculated by substituting the number of objects and the number of fragments into the following equation (1).

[0085] Yield (%) = 1 - (number of fragments) / (number of objects) × 100 ... Equation (1) In the embodiments, even the lowest yield rate reached 97%, while in the comparative examples, even the highest yield rate was 82% in experimental category 24, which could not achieve the same high yield rate as the embodiments.

[0086] [Table 1] [Table 2] [Table 3] This disclosure may include the following solutions.

[0087] (Option 1) A method for manufacturing a seamless capsule, wherein, The process includes dripping coolant from the end of a nozzle into a flow path of a forming tube, and forming a seamless wet capsule from the aforementioned droplets. The aforementioned nozzle has an inclined portion that slopes inward from its midpoint toward its end. The distance Z between the vertex of the space surrounded by the imaginary surface formed by extending the outer surface of the aforementioned inclined portion toward the lower end of the aforementioned end and the upper end of the aforementioned forming tube is within the range of -10 mm ≤ Z ≤ 6 mm. When Z < 0, the aforementioned vertex is located lower than the upper end of the aforementioned forming tube. When Z > 0, the aforementioned vertex is located higher than the upper end of the aforementioned forming tube.

[0088] (Option 2) The method for manufacturing seamless capsules described in Scheme 1, wherein, In the vertical section of the aforementioned nozzle passing through the central axis of the aforementioned nozzle, the angle between the two straight lines connecting the upper and lower ends of the outer surface of the aforementioned inclined portion is in the range of 20° to 70°.

[0089] (Option 3) The method for manufacturing the seamless capsule described in Scheme 1 or 2, wherein, In the horizontal cross-section of the aforementioned nozzle, which is orthogonal to the central axis of the aforementioned nozzle, the outline of the aforementioned inclined portion is a circle, an ellipse, or a polygon.

[0090] (Option 4) The manufacturing method of the seamless capsule described in any of Schemes 1 to 3, wherein the coefficient of variation of the particle size of the aforementioned wet capsule is 0.1 or less.

[0091] (Option 5) The method for manufacturing a seamless capsule as described in any of Schemes 1 to 4, wherein the aforementioned forming step includes a step of positioning the end of the nozzle below the surface of the coolant.

[0092] (Option 6) The method for manufacturing a seamless capsule as described in any of schemes 1 to 5, wherein, It also includes a drying process of drying the aforementioned wet capsules to obtain dry capsules.

[0093] (Option 7) The method for manufacturing seamless capsules described in Scheme 6, wherein, The coefficient of variation of the particle size of the aforementioned dry capsules is less than 0.1.

[0094] (Option 8) The method for manufacturing a seamless capsule as described in any of schemes 1 to 7, wherein, The coolant flowing into the aforementioned forming pipe accumulates in the cooling reservoir. The aforementioned inclined portion and the upper end of the aforementioned forming tube are disposed within the aforementioned cooling reservoir. The aforementioned coolant reservoir has a bottom wall, a top wall, and a peripheral wall. At least one of the aforementioned nozzle, the aforementioned upper wall, and the aforementioned forming tube is configured to be able to move up and down along the central axis of the aforementioned nozzle.

[0095] Explanation of reference numerals in the attached figures 1 Nozzle 1a terminal 1b Flange portion 1c Content liquid inflow port 1d film fluid inflow port 1e Intermediate liquid inflow port 2. Contents tank 2a Content fluid supply tube 3 film liquid tank 3a Film Fluid Supply Tube 6. Coolant reservoir 6a bottom wall 6b Upper wall 6c Perimeter Wall 6d Coolant inlet port 6e spacer 6f seal 7. Coolant tank 8 Coolant supply pipe 9. Cooling device 10 Forming tube 10a upper end Pumps 11 to 13 14 sieves 15 Dryer 21. Central nozzle 22 Outermost nozzle 23 Intermediate nozzle 25 Inclined section 25a Outer surface 25b Straight Line 25c upper end 25d lower end 26 Imaginary Surfaces 27 Vertex 31 Nozzle body 32 lids 41 Contents 42 membrane fluid 43 Intermediate liquid 49 Coolant 49L liquid level 50 Seamless Capsules 50w wet capsules 50-day dry capsules 51 Contents 52. Skin layer 53 Intermediate Layer 59 Composite Jet A central axis Z distance H distance θ is the angle.

Claims

1. A method for manufacturing a seamless capsule, wherein, The process includes dripping coolant from the end of a nozzle into a flow path of a forming tube, and forming a seamless wet capsule from the droplets. The nozzle has an inclined portion that slopes inward from its middle towards its end. The distance Z between the vertex of the space surrounded by the imaginary surface formed by extending the outer surface of the inclined portion toward the lower end and the upper end of the forming tube is within the range of -10 mm ≤ Z ≤ 6 mm. When Z < 0, the vertex is located lower than the upper end of the forming tube, and when Z > 0, the vertex is located higher than the upper end of the forming tube.

2. The method for manufacturing a seamless capsule according to claim 1, wherein, In the vertical section of the nozzle passing through the central axis of the nozzle, the angle between a pair of straight lines connecting the upper and lower ends of the outer surface of the inclined portion is in the range of 20° to 70°.

3. The method for manufacturing a seamless capsule according to claim 1 or 2, wherein, In a horizontal cross-section of the nozzle orthogonal to its central axis, the outline of the inclined portion is circular, elliptical, or polygonal.

4. The method for manufacturing a seamless capsule according to any one of claims 1 to 3, wherein, The coefficient of variation of the particle size of the wet capsule is less than 0.

1.

5. The method for manufacturing a seamless capsule according to any one of claims 1 to 4, wherein, The forming process includes a step of positioning the tip of the nozzle below the surface of the coolant.

6. The method for manufacturing a seamless capsule according to any one of claims 1 to 5, wherein, It also includes a drying process of drying the wet capsules to obtain dry capsules.

7. The method for manufacturing a seamless capsule according to claim 6, wherein, The coefficient of variation of the particle size of the dry capsules is less than 0.

1.

8. The method for manufacturing a seamless capsule according to any one of claims 1 to 7, wherein, The coolant flowing into the forming tube is stored in the cooling reservoir. The inclined portion and the upper end of the forming tube are disposed within the cooling reservoir. The coolant reservoir has a bottom wall, a top wall, and a peripheral wall. At least one of the nozzle, the upper wall, and the forming tube is configured to be movable up and down along the central axis of the nozzle.

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