JP2020040059A - Suction type fine particle coating method and device - Google Patents

Abstract

To provide a technique that a tubular workpiece is coated with a plurality of fine particles and the plurality of fine particles are easily fixed in a state of being dispersed without unevenness on the coat surface of the workpiece.SOLUTION: A tubular workpiece 14 is placed so that at least a first opening end 18 out of the first opening end 18 and a second opening end 19 of the workpiece 14 is positioned in a container (not illustrated). A solution (not illustrated) where a plurality of fine particles are mixed in a volatile solvent in a dispersion state is sprayed by a sprayer 26 with a compressed gas 20 and mist is injected into the container. A part of the mist introduced into a cavity 12 of the workpiece 14 is suctioned from the second opening end 19 of the workpiece 14 by a suction device 70. The mist is accelerated to be stuck on the inner surface of the workpiece 14 by a turbulence flow generator 300 or a reciprocated flow generator 400.SELECTED DRAWING: Figure 8

Description

  The present invention relates to a technique for coating a work having cavities open at both ends with a plurality of fine particles, and in particular, the plurality of fine particles are uniformly distributed on a coated surface (a coated surface or a coated surface of the work) of the work. The present invention relates to a technology that facilitates being fixed in a state.

  Techniques for coating the surface of a workpiece with a plurality of particles already exist.

  To explain this in detail, Patent Literature 1 discloses a technique of coating the surface of a medical device such as a stent, a catheter, or a graft with a copolymer. Specifically, the coating method includes immersion and spraying. It discloses that there exist a coating method, a spin coating method and a mixed solution impregnated sponge coating method. This Patent Document 1 further discloses that when a coat layer is formed on a thin and narrow inner surface of a catheter or the like, the catheter is immersed in a coating solution, and the inside of the system is depressurized and defoamed. .

  Patent Document 2 discloses depositing silver nanoparticles as an antibacterial substance on the outer surface of a tubular catheter having an outer surface, an inner surface and a lumen defined by the inner surface, Also discloses depositing silver nanoparticles.

  This patent document further discloses a method of embedding silver nanoparticles in a material constituting a catheter, and alternatively and / or additionally immersing the catheter in a solution containing silver chloride, Discloses a method for attaching silver particles to the inner and outer surfaces of a catheter.

  This patent further discloses that silver particles are evenly distributed on both the inner and outer surfaces of the catheter over the entire length of the catheter.

  Patent Literature 3 discloses that a metal oxide or the like is vapor-deposited on an inner surface, an outer surface, or an inner and outer surface of a container-shaped or bag-shaped work, and then the vapor-deposited surface is polymer-coated, thereby reducing the gas barrier property of the work. It discloses a method for improving it.

  Patent Literature 4 discloses a technique in which an electrostatic atomizer is used, and pharmaceutical particles are sprayed through a deflector of the atomizer and applied to the surface of a stent.

  Patent Document 5 discloses a method of coating a stent by an electrostatic spray method using a compressed gas. Specifically, according to this method, a plurality of microdroplets are sprayed into a closed space under an electric field, each microdroplet is charged, and when each microdroplet evaporates, the electric charge of each microdroplet becomes an active ingredient. A concentrated spray of charged particles results. Each charged particle is moved toward and adheres to the stent by the electric field.

  Patent Literature 6 discloses a method for simultaneously coating the outer surface and the inner surface of a medical device such as a stent. Specifically, according to this method, while the medical device is supported and rotated by the roller, the liquid polymer is simultaneously sprayed, dropped, immersed or injected on the inner surface and the outer surface of the lumen of the medical device. Applied. An applicator is inserted into the stent to apply the luminal surface.

  Patent Document 7 discloses a method of spraying and applying a plurality of particles to a target surface. The method includes a solution heating step of heating a volatile spray liquid in which the plurality of particles are mixed in a dispersed state, a gas heating step of heating a compressed gas, and the heated compressed gas. Is supplied to a spray gun together with the heated spray liquid, thereby atomizing the spray liquid using the compressed gas and spraying the spray liquid from the spray gun. I have.

  The solution heating step and the gas heating step include a step in which the spray liquid is vaporized substantially entirely before the spray liquid ejected from the spray gun reaches the target surface. And heating the spray liquid and the compressed gas to a temperature that is realized by the gas heating step in cooperation with each other.

JP-A-2006-63846 JP-T-2009-505792 JP 2002-145346 A JP 2004-532665A JP 2006-511259 A Japanese Patent No. 5014433 JP 2015-171687 A

  However, with the technology described in Patent Documents 1 to 7, it is impossible to uniformly coat the entire inner surface of a work having a thin and long lumen with a plurality of fine particles.

  In the context of the circumstances described above, the present invention is a technique for coating a work having a cavity that is open at both ends with a plurality of fine particles, wherein the plurality of fine particles are uniformly dispersed on the coated surface of the work. It is an object of the present invention to provide something that can be easily fixed.

  The following aspects are obtained by the present invention. Each mode is divided into sections, each section is numbered, and if necessary, is described in a form in which the numbers of other sections are cited. This is to facilitate understanding of some of the technical features that can be adopted by the present invention and combinations thereof, and the technical features and the combinations thereof that can be adopted by the present invention are limited to the following aspects. Should not be interpreted as That is, it should be construed that it is not hampered that technical features not described in the following embodiments but described in the present specification are appropriately extracted and adopted as technical features of the present invention.

  Furthermore, listing each section in a form that quotes the number of the other section does not necessarily prevent the technical features described in each section from being separated from and independent of the technical features described in the other sections. It is to be construed that the technical features described in the respective sections can be appropriately made independent according to their properties.

(1) A method of coating at least the inner surface of the inner and outer surfaces of a work having a cavity opened at both ends with a plurality of fine particles,
A mist generating step of spraying a solution formed by mixing the plurality of fine particles in a dispersed state in a volatile solvent with a compressed gas to generate a mist,
Applying the generated mist to a first opening end of the work;
A suction step of sucking a part of the mist introduced into the cavity of the work from a second opening end of the work.

(2) the suction step is performed by applying a suction device to a second opening end of the work;
The suction-type fine particles according to item (1), wherein the suction device is a contact type that performs the suction by contacting the second opening end or a non-contact type that performs the suction without contacting the second opening end. Coating method.

(3) In the suction step, a part of the mist that is discharged from the second opening end of the work by the suction is returned to the first opening end or a vicinity thereof (for example, a container that stores the work). The method of coating fine particles according to item (1) or (2), which comprises a step.

(4) The method further includes a speed adjusting step of adjusting a speed at which the mist passes through the cavity of the work, thereby controlling a characteristic of the plurality of fine particles contacting and adhering to the inner surface of the work. Or the suction type fine particle coating method according to any one of items (3) to (3).

(5) In the speed adjusting step, the pressure (for example, a container for accommodating the work) at or near the first opening end and the pressure at or near the second opening end (communicating with the gas outlet or the atmosphere of the suction device). (4) The suction type fine particle coating method according to the above mode (4), comprising a step of adjusting the speed by adjusting a pressure difference between the pressure and the pressure of the mouth.

(6)
The suction type fine particle coating method according to any one of (1) to (5), further comprising a heating step of heating the compressed gas prior to the formation of the mist.

(7) Further, prior to applying the mist to the work, a base paint functioning as a binder is applied to a target coating surface of the inner and outer surfaces of the work which is to be coated with the plurality of fine particles. A pre-treatment step of forming an uncured coating and thereby pre-treating said target coating surface;
The suction-type fine particle coating method according to any one of (1) to (6), wherein the target coating surface is brought into contact with the mist in a state where the base paint is uncured.

(8) The work is a medical cylindrical stent or catheter,
The plurality of fine particles each act as an antimicrobial agent,
The suction-type fine particle coating method according to any one of (1) to (7), wherein the method is performed to perform antibacterial processing in which both inner and outer surfaces of the work are coated with the plurality of fine particles at once.

(9) The suction-type fine particle coating method according to any one of (1) to (8), wherein the inner surface of the work has a cross section represented by a circle having a diameter of 2 mm or less in a free state of the work.

(10) An apparatus for coating the inner surface of a tubular work having cavities open at both ends with a plurality of fine particles, or for coating the inner and outer surfaces of the work with a plurality of fine particles at once,
A container,
A holder for holding the work so that at least the first open end of the first open end and the second open end of the work is located in the container;
A sprayer for spraying a mist into the container by spraying a solution formed by mixing the plurality of fine particles in a volatile solvent in a dispersed state together with a compressed gas,
A suction device applied to a second open end of the work, the suction device sucking a portion of the mist introduced into the cavity of the work from the second open end.

(11) The suction device according to (10), wherein the suction device generates a jet, and jets the jet in a direction crossing the second opening end while contacting the second opening end of the work. Suction type fine particle coating equipment.

(12) A method of coating an inner surface of a tubular work having a cavity opened at both ends with a plurality of fine particles,
A mist generating step of spraying a solution formed by mixing the plurality of fine particles in a volatile state in a volatile solvent with a heated compressed gas to generate a mist;
A pretreatment step of applying a liquid binder to the inner surface of the work in a planar shape, thereby pretreating the inner surface,
An applying step of applying the mist to a first open end of the work before the binder is cured;
A suction step of sucking a part of the mist introduced into the cavity of the work from a second opening end of the work.

(13) When the suction step is performed, the mist is sprayed on the inner surface, and when the volatile solvent evaporates in the mist, the plurality of fine particles adhere to the binder in a state where they are dispersed with each other. The suction-type fine particle coating method according to (12), wherein when the binder is cured, the plurality of fine particles are fixed on the binder in a state of being dispersed.

(14) A tubular stent to be placed and used in a vessel of a living body,
An inner surface, a lumen defined by the inner surface, and an outer surface;
Both the inner surface and the outer surface are coated with an antibacterial film by spray coating with a plurality of antibacterial fine particles,
A double-sided coated stent, wherein the diameter of the inner surface is 2 mm or less.

(15) The double-sided coated stent according to (14), which is used by being placed in the bile duct of the living body.

(16) A method of coating at least the inner surface of the inner and outer surfaces of a work having a cavity opened at both ends with a plurality of fine particles,
A holding step of holding the work so that at least the first open end of the first open end and the second open end of the work is located in the container;
A sprayer, a mist generating step of spraying a solution composed of the plurality of fine particles mixed in a volatile state in a volatile solvent together with a compressed gas to generate a mist,
Applying the generated mist to a first opening end of the work;
A suction device for sucking a part of the mist introduced into the cavity of the work from a second opening end of the work by a suction device;
An inner surface adhesion promoting step of promoting the plurality of fine particles to adhere to the inner surface of the work,
The inner surface adhesion promotion step is
A turbulence generator, which turbulences the mist generated in the mist generation step and introduces the turbulent mist into the cavity from the first opening end;
A suction type fine particle coating method for performing at least one of a reciprocating flow step of reciprocating a mist introduced into the cavity from the first opening end by a reciprocating flow generator.

(17) A method of coating at least an inner surface of both inner and outer surfaces of a work having a cavity opened at both ends with a plurality of fine particles,
A holding step of holding the work so that at least the first open end of the first open end and the second open end of the work is located in the container;
A sprayer, a mist generating step of spraying a solution composed of the plurality of fine particles mixed in a volatile state in a volatile solvent together with a compressed gas to generate a mist,
Applying the generated mist to a first opening end of the work;
A suction device for sucking a part of the mist introduced into the cavity of the work from a second opening end of the work by a suction device;
When the pressure of the mist in the container is to exceed a preset relief pressure, a pressure regulating step of opening a relief valve and allowing a part of the mist to flow out of the container,
In order to coat the inner and outer surfaces of the work at once, by installing the relief valve in the container at a position closer to the second opening end than the first opening end, in the container, to the mist, An outer surface adhesion promoting step of generating a flow from the first opening end toward the second opening end along the outer surface of the work, thereby promoting the plurality of fine particles to adhere to the outer surface of the work. Suction type fine particle coating method including.

(18) An apparatus for coating an inner surface of a tubular work having a cavity opened at both ends with a plurality of fine particles, or for coating both inner and outer surfaces of the work with a plurality of fine particles at once,
A container,
A holder for holding the work so that at least the first open end of the first open end and the second open end of the work is located in the container;
A sprayer for spraying a mist into the container by spraying a solution formed by mixing the plurality of fine particles in a volatile solvent in a dispersed state together with a compressed gas,
A suction device that is applied to a second opening end of the work and suctions a part of the mist introduced into the cavity of the work from the second opening end;
An inner surface adhesion promoting device that promotes the plurality of fine particles to adhere to the inner surface of the work,
The inner surface adhesion promotion device is
A turbulence generator that turbulates the mist generated by the sprayer and introduces the turbulent mist into the cavity from the first opening end;
A reciprocating flow generator configured to reciprocate the mist introduced into the cavity from the first opening end.

(19) An apparatus for coating an inner surface of a tubular work having a cavity opened at both ends with a plurality of fine particles, or for coating both inner and outer surfaces of the work with a plurality of fine particles at once,
A container,
A holder for holding the work so that at least the first open end of the first open end and the second open end of the work is located in the container;
A sprayer for spraying a mist into the container by spraying a solution formed by mixing the plurality of fine particles in a volatile solvent in a dispersed state together with a compressed gas,
A suction device that is applied to a second opening end of the work and suctions a part of the mist introduced into the cavity of the work from the second opening end;
A relief valve that opens when the pressure of the mist in the container attempts to exceed a preset relief pressure to allow a portion of the mist to flow out of the container,
The relief valve is disposed on the container at a position closer to the second opening end than the first opening end, whereby the mist is provided in the container along the outer surface of the work in the mist. A suction type fine particle coating apparatus in which a flow is generated from an end toward the second opening end, thereby promoting adhesion of the plurality of fine particles to an outer surface of the work.

FIG. 1 is a side view schematically showing an overall configuration of a suction-type fine particle coating apparatus according to an exemplary embodiment of the present invention. FIG. 2 is a side view showing a portion in a region surrounded by a circle in FIG. 1 in an enlarged manner. FIG. 3 is a side sectional view showing an example of the suction device shown in FIG. 1 in an enlarged manner. FIG. 4 is a side sectional view showing another example of the suction device shown in FIG. 1 in an enlarged manner. FIG. 5 is a process chart for explaining an example of a suction-type fine particle coating method using the suction-type fine particle coating apparatus shown in FIG. FIG. 6 is a side cross-sectional view showing another example of the suction device shown in FIG. 1 in an enlarged manner. FIG. 7 schematically shows an entire configuration of a suction-type fine particle coating apparatus according to another exemplary embodiment of the present invention, and also exemplifies a flow of mist in a container of the suction-type fine particle coating apparatus. FIG. FIG. 8A is a side view for explaining a first specific example of a method for sucking mist in a work cavity in a container of a suction-type fine particle coating apparatus according to some of the above embodiments, and FIG. 8) is a side view for explaining a second specific example of the mist suction method, and FIG. 8C is a side view for explaining a third specific example of the mist suction method.

  Hereinafter, some of the more specific exemplary embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 schematically shows an entire configuration of an example of a suction-type fine particle coating apparatus (hereinafter, simply referred to as “coating apparatus”) 10 used for performing a suction-type fine particle coating method according to an exemplary embodiment of the present invention. It is shown in a side view.

  As shown in FIGS. 1 and 2, the coating method is to coat an inner surface 16 of a work 14 having a cavity 12 opened at both ends with a plurality of fine particles (particles, nanoparticles, etc.) , 17 are coated at once with a plurality of fine particles. The work 14 has a first open end 18 located on the right side in the figure and a second open end 19 located on the left side in the figure.

  Since the first open end 18 and the second open end 19 are located on the upstream side and the downstream side with respect to the flow of the mist described later in the cavity 12 of the work 14, respectively, the first open end 18 and the second open end Reference numerals 19 are also an upstream open end and a downstream open end, respectively.

  As shown in FIG. 2, in this coating method, a plurality of fine particles are transferred to a target of the workpiece 14 by a wet method (a plurality of fine particles are adhered and fixed on the surface of an uncured coating film described later) and by suction (suction). It is applied to the front surface (in some cases, only the inner surface 16 is selected, and in other cases, both the inner and outer surfaces 16, 17 are selected).

  As shown in FIG. 1, the coating apparatus 10 includes an air pressure source 20 that pressurizes air and stores the air under pressure, a plurality of hoses 22, and a heater 24 that heats compressed air supplied from the air pressure source 20. , A sprayer 26, a tank 28, and a container 30 having a closed space 29.

  To explain these components individually, the air pressure source 20 contains compressed air, which is an example of compressed gas. The air pressure source 20 includes, for example, an electric compressor (not shown), and further optionally, supplies a gas that has been subjected to a specific process (for example, a sterilization process, a process for obtaining medical-grade air). It has a tank (not shown) for housing.

  The sprayer 26 switches between an interrupted state in which the entry of compressed air from the outside is shut off and an operation state in which the entry of compressed air from the outside is permitted, in response to an instruction from the operator or automatically. The sprayer 26 generates a mist using the compressed air discharged from the heater 24, and injects the mist into the container 30.

Specifically, the sprayer 26 sprays the solution supplied from the tank 28 together with the compressed gas supplied from the air pressure source 20 to generate a mist. The spray pressure of the sprayer 26 is about 0.5 to about 1.5 kg / cm ² . The sprayer 26 has a divergent diffuser 34 for injecting mist in a diffusive manner. The diffuser 34 is disposed in front of the first opening end 18 of the work 14, that is, at a position away from the upstream of the mist flow.

  The diffuser 34, which is the outlet of the mist from the atomizer 26, does not contact the first open end 18, but is separated from the first open end 18. As a result, the mist comes into contact with the first opening end 18 without leakage.

  An example of the heater 24 is an in-line type, specifically, a method in which a gas passage in the heater 24 is arranged in an axial direction along a path through which the compressed air flows, and the compressed air is heated in the flow process. .

  The heater 24 has a safety valve (relief valve) 36. The safety valve 36 has a function of adjusting the pressure so that the pressure of the compressed air does not exceed the upper limit pressure. The upper limit pressure can be arbitrarily set by an operator, and as a result, the pressure of the compressed air is adjusted.

  The heater 24 allows the compressed air supplied from the air pressure source 20 to escape from the heater 24 to the outside, even in a state where the compressed air is supplied to the sprayer 24 and in a state where the compressed air is cut off by the sprayer 24. A relief hole 38 is provided for forcibly air cooling the heater 24 itself. According to one example of the heater 24, the compressed air is heated and maintained at about 50 to about 70C.

  The tank 28 contains a solution in which a plurality of fine particles are mixed in a volatile solvent in a dispersed state under pressure. One example of a volatile solvent is ethyl alcohol. One example of a microparticle is a particle (eg, a nanoparticle) having a diameter of about 80 nm (eg, about 80 to about 120 nm). One example of the fine particles is antimicrobial fine particles having antibacterial properties (or antimicrobial agent fine particles). Further, an example of the fine particles has a plurality of metallic silver particles carried on the surface thereof. One example of a solution is an antimicrobial solution. One example of the antimicrobial solution contains about 0.1 to about 1.0 part by weight of antimicrobial particles per 100 parts by weight of alcohol.

  The solution in the tank 28 is supplied to the inlet of the sprayer 24 by a pressure pump (not shown). The solution in the tank 28 is heated and maintained at about 30 to about 50 ° C. by a solution heating device (not shown).

  The coating apparatus 10 further has a safety valve (relief valve) 50 mounted on the container 30. The safety valve 50 has a function of adjusting the pressure so that the pressure of the mist in the container 30 does not exceed the relief pressure of the safety valve 50, that is, the upper limit pressure. The upper limit pressure can be arbitrarily set by an operator, and as a result, the upper limit pressure of the mist in the container 30 is adjusted. When the mist pressure (positive pressure) is adjusted, the pressure difference between the mist pressure and the atmospheric pressure is adjusted. As a result, the mist is filled in the container 30 while being pressurized at a pressure higher than the atmospheric pressure.

  As a result of the operation of the atomizer 26, when the pressure of the mist in the container 30 tries to exceed the relief pressure (set pressure), the safety valve 50 opens and a part of the mist flows out of the safety valve 50 to the outside of the container 30. As a result, the mist pressure in the container 30 is prevented from exceeding the relief pressure.

  In this coating apparatus 10, at least the first open end 18 of the first open end 18 and the second open end 19 of the work 14 is located in the container 30 in a horizontal posture (the mist is the first open end 18). (Which can be introduced from the open end 18).

  In one example, only the first open end 18 of the first open end 18 and the second open end 19 of the work 14 is disposed at a position separated inward from the inner wall surface 200 of the container 30 (see FIG. 7). In another example, as shown in FIG. 1, both the first open end 18 and the second open end 19 of the work 14 are arranged at positions separated inward from the inner wall surface 200 of the container 30.

  As a result of the corresponding one of the first open end 18 and the second open end 19 being separated inward from the inner wall surface 200 of the container 30, each open end 18, 19 is exposed in the internal space of the container 30, and mist is generated. The coating is applied to each of the open ends 18 and 19 without any gap without being disturbed by the container 30.

  In the example shown in FIG. 1, the work 14 is held in the container 30 in a horizontal position, but may be held in another position, for example, a vertical position or an inclined position. When held in a posture other than the horizontal posture, gravity acts on the mist in the cavity 12 of the work 14.

  When a layout is adopted in which the first opening end 18 of the work 14 in the non-horizontal posture is located on the upper side, the second opening end 19 is located on the lower side, and the sprayer 26 is located above the first opening end 18. In the meantime, the mist in the cavity 12 of the work 14 is promoted to flow down in the cavity 12 and flow out from the second opening end 19 due to the synergistic effect of the suction by the suction device 70 described below and the fall due to its own weight. You.

  The coating apparatus 10 has a suction device 70 that is applied to the second open end 19 of the work 14 and suctions a part of the mist introduced into the cavity 12 of the work 14 from the second open end 19.

  As shown in FIG. 3, an example of the suction device 70 is a method in which the work 14 is sucked by contacting (mechanically engaging) with the work 14, and a method using a piston that performs intermittent motion. is there.

  First, the configuration will be described. The suction device 70 has a piston 72, a cylinder 74 to which the piston 72 is fitted, and a nozzle 76 extending outwardly and axially from the cylinder 74.

  The nozzle 76 is a cylindrical body having a hollow penetrating therethrough, airtightly penetrates the wall of the container 30 in the thickness direction thereof, and further extends from the second open end 19 of the work 14 into the hollow 12 of the work 14. Approach. The nozzle 76 and the work 14 are fitted by the approach or the insertion. Since the nozzle 76 is fixed to the wall of the container 30, the nozzle 76 also functions as a holder that holds the work 14 at the same position with respect to the container 30.

  Next, the operation of the suction device 70 will be described. When the rod 78 of the piston 72 is manually or mechanically retracted and the piston 72 retreats from the cylinder 74, the volume of the pressure chamber 80 in the cylinder 74 increases, Thereby, a pressure (for example, a negative pressure) lower than the pressure in the container 30 is generated in the pressure chamber 80.

  As a result, a part of the mist in the container 30 is sucked into the pressure chamber 80, and the mist flows from the first open end 18 to the second open end 19 in the cavity 12. As a result of the mist in the cavity 12 being sucked by the suction device 70, even if the cavity 12 is thin and long, the entire inner surface 16 thereof is evenly (without gaps) and uniformly (with a uniform dispersion density). A plurality of fine particles can be transported and attached.

  When this suction device 70 is used, the volume of the pressure chamber 80 needs to be larger than the volume of the cavity of one work 14. When the volume of the pressure chamber 80 is equal to or larger than the volume of one work 14 but smaller than the total volume of two works 14, every time the coating operation for one work 14 is completed, It is necessary to pull out the workpiece 14 from the nozzle 76 with the nozzle 76 left in the container 30 and remove it from the container 30, and to push the piston 72 into the cylinder 74.

  On the other hand, when the volume of the pressure chamber 80 is equal to or larger than the volume of the plurality of works 14, the nozzle 76 is left in the container 30 every time the coating operation is completed for one work 14. It is necessary to pull out the workpiece 14 from the nozzle 76 while taking it out of the container 30 and to push the piston 72 into the cylinder 74 each time the coating work on the plurality of workpieces 14 is completed.

  As shown in FIG. 4, another example of the suction device 70 is a method of sucking the work 14 by contacting (mechanically engaging) with the work 14 and using a pump that performs a continuous motion. It is also a method.

  First, to explain the configuration, the suction device 70 includes a pump 90, a suction nozzle 92 extending from a suction port of the pump 90, a discharge hose 94 extending from a discharge port of the pump 90, and a midway of the discharge hose 94. A check valve 96 provided at the end.

  The suction nozzle 92 penetrates the wall of the container 30 airtightly in the thickness direction of the container 30 in the same manner as the nozzle 76 and further partially enters the cavity 12 of the work 14 from the second open end 19 of the work 14. I do. As a result, the suction nozzle 92 and the work 14 are fitted. Since the suction nozzle 92 is fixed to the wall of the container 30, the suction nozzle 92 also functions as a holder that holds the work 14 at the same position with respect to the container 30.

  The downstream end of the discharge hose 94 airtightly penetrates the wall of the container 30 in its thickness direction, so that the mist sucked by the pump 90 and discharged by the pump 90 returns to the container 30. Let me do. The check valve 96 prevents the mist in the container 30 from flowing back toward the pump 90.

  Next, the operation of the suction device 70 will be described. When the pump 90 is continuously operated by a motor (not shown), the pressure (for example, negative pressure) in the suction nozzle 92 becomes lower than the pressure in the container 30. Become.

  As a result, a part of the mist in the container 30 is sucked into the pump 90, and the mist flows from the first open end 18 to the second open end 19 in the cavity 12. As described above, the mist in the cavity 12 is sucked by the suction device 70, so that even if the cavity 12 is thin and long, the plurality of fine particles can be uniformly and uniformly transported and adhered to the entire inner surface 16. It becomes possible.

  While the capacity of the pressure chamber 80 in the example shown in FIG. 3 is limited, when the suction device 70 shown in FIG. 4 is used, the pump corresponding to the pressure chamber 80 is used as long as the suction device 70 is continuously operated. The chamber volume is infinite.

  Therefore, every time the coating operation is completed for one work 14, the work 14 can be pulled out from the nozzle 76 and taken out of the container 30 while the suction nozzle 92 remains in the container 30.

  FIG. 5 shows a process diagram of the coating method.

  First, in step S1, of the inner surface (inner surface of the cylinder) 16 and the outer surface (outer surface of the cylinder) 17 of the work 40, the one to be subjected to antibacterial processing is selected as the target coating surface (only the inner surface 16 or the inner and outer surfaces 17, 18). . Further, the selected coating surface is uniformly and uniformly coated with a base coating material (for example, a clear coating material or a medical grade coating material) by a method such as dipping or spraying.

  As a result, as shown in FIG. 2, an uncured coating film is formed on the target coating surface of the work 14, and the uncured coating film serves as a binder for fixing the plurality of antimicrobial fine particles to the target coating surface. Function. Thereby, the pre-processing of the work 14 is completed.

  Next, in step S2, the work piece 14 to be coated fits into the container 30 and the nozzle 76 or 92 fits into the cylindrical end portion having the second open end 19 of the work piece 14 with almost no gap. Is inserted into. Thereby, the work 14 is held at a predetermined position in the container 30.

  In the example shown in FIG. 1, the holder 60 is configured to hold the workpiece 14 by grasping the central portion in the axial direction generally from the outside. On the other hand, as in another example shown in FIG. 7, the nozzle 76 (or 92) of the suction device 70 is used instead of the holder 60, and the nozzle 76 is inserted into the second opening end 19 from outside. Accordingly, the work 14 may be held in a cantilever manner at the second open end 19.

  In the example shown in FIG. 7, the nozzle 76 extends integrally or separately from a stationary member outside the container 30 and penetrates the wall of the container 30 to partially extend into the container 30 at its distal end. A part of the inner surface 16 or a part of the outer surface 17 that constitutes the second open end 19 of the work 14 to thereby form the work 14 into a cantilever shape, for example. And an example of a supporting member or a fixing member for supporting or fixing.

  Also in this example, the second opening end 19 is disposed at a position separated inward from the inner wall surface 200 of the container 30.

  Subsequently, in step S3, the antibacterial solution is turned into a mist and sprayed into the container 30 by operating the sprayer 26. By the spraying, the internal space of the container 30 is entirely filled with mist. The mist is applied to the first open end 18 of the work 14, and a part of the mist can be introduced into the first open end 18. That is, step S3 includes an example of the mist forming step and an example of the applying step.

  At this time, the internal space of the container 30 is filled with mist, and the pressure of the mist (mist pressure) at that time is higher than the atmospheric pressure and lower than the relief pressure of the safety valve 50. In the container 30, the mist is in a floating state that is generally stationary as illustrated in FIG. However, when the mist pressure attempts to exceed the relief pressure, the mist flows out of the safety valve 50.

  On the other hand, as illustrated in FIG. 1, the safety valve 50 is arranged so as to communicate with a downstream portion (a portion near the second opening end 19) of the space in the container 30. As a result, when the mist flows out of the safety valve 50, a flow of the mist from the sprayer 26 toward the second open end 19 is generated.

  The flow of the mist from the sprayer 26 toward the second open end 19 is particularly likely to be generated outside the work 14 in the container 30. As a result, due to the generation of this flow, the frequency of the new mist coming into contact with the outer surface 17 of the work 14 increases, and as a result, the time required for the density of the fine particles attached to the outer surface 17 to increase to the target value increases. There is a possibility that the particle size is reduced and the adhesion of the fine particles to the outer surface 17 is promoted as compared with the case where there is no such flow.

  Some of the mist ejected from the atomizer 26 is drawn into the cavity 12 of the work 14 and contacts the inner surface 16 owing to the suction device 70, while another part of the same mist is 14 contacts the outer surface 17 thereof. When the mist is stationary, the mist generally adheres statically to the outer surface 17, whereas, as described above, the mist moves downstream along the outer surface 17 if the mist has a flow. Attaches to outer surface 17.

  However, if the cavity 12 of the work 14 is narrow and narrow (for example, the inner diameter of the work is 2 mm or less), if the suction device 70 is not present, for example, focusing on the flow of the mist in the cross section of the work 14, The portion forms a boundary layer that is fixed to the inner surface (inner wall surface) 16, and the thickness of the boundary layer occupies the diameter of the inner surface 14. Since the boundary layer is formed on the inner surface 14, it effectively reduces the diameter dimension of the inner surface 14. Therefore, the flow resistance when the mist passes through the cavity 12 increases. As a result, the mist cannot smoothly pass through the inside of the cavity 12 and be discharged from the second opening end 19, and the mist cannot be evenly and uniformly applied to the inner surface 16.

  On the other hand, in each of the examples shown in FIGS. 1 and 7, the suction device 70 is present, and as a result, the suction by the suction device 70 overcomes the flow resistance and causes the cavity 12 ( For example, it is possible to smoothly pass through the inside of a work having an inner diameter of 2 mm or less.

  Thereafter, in step S4, by operating the suction device 70 together with, for example, the sprayer 26, the part of the mist in the container 30 introduced from the first open end 18 into the cavity 12 of the work 14 Is sucked from the second opening end 19. As a result, the mist is actively drawn into the cavity 12 from the first open end 18 of the work 14, and as a result, a flow of the mist from the first open end 18 to the second open end 19 occurs in the cavity 12. Is done.

  That is, according to the present embodiment, the mist passes through the entire inside of the cavity 12 from the first opening end 18 to the second opening end 19 by the cooperative action of the pushing of the mist by spraying and the drawing of the mist by suction. It is promoted. As in the example shown in FIG. 7, the mist ejected from the sprayer 26 is sucked into the work 14 by being accelerated by the suction device 70. In the figure, the arrows indicate the direction of the flow and the flow velocity, and the longer the arrow, the higher the flow velocity.

  In the present embodiment, a part of the same mist ejected from the same sprayer 26 directly contacts the inner surface 16 of the work 12 without passing through the outer surface 17 of the work 12, and another part is It directly contacts the outer surface 17 of the work 12 without passing through the inner surface 16 of the work 12.

  Therefore, in the present embodiment, as in the respective examples shown in FIGS. 1 and 7, a part and another part of the mist ejected from the sprayer 26 are respectively attached to the inner surface 16 and the outer surface 17 of the work 14. Each will be deposited in parallel with one another, ie simultaneously.

  In the present embodiment, for example, a boundary layer of the mist is suppressed from being formed on the inner surface (inner wall surface) 16 of the work 14 due to the mist suction action. Thereby, the mist does not stay on the inner surface 16 unnecessarily, and the smooth passage in the axial direction through the cavity 12 is promoted. Therefore, in the process in which the mist passes through the cavity 12 in the axial direction, the tendency of the plurality of droplets constituting the mist to aggregate and cluster together before adhering to the inner surface 16 is reduced. As a result, the plurality of fine droplets adhere to the inner surface 16 of the work 14 in the middle while passing in the cavity 12 in the axial direction while maintaining the dispersed state.

  In the container 30, an outer surface coating is also performed in parallel with or prior to the inner surface coating, so that the sprayed mist uniformly and uniformly adheres to the outer surface 17 of the same work 14.

  When the suction is performed, the mist is sprayed on the inner surface 16, and when the ethyl alcohol (the volatile solvent) evaporates in the mist, the plurality of antimicrobial fine particles are dispersed on each other on the uncured coating film. Adhere as the binder. When the coating film is dried and cured, the plurality of fine particles are fixed on the coating film in a state of being dispersed. Evaporation of the ethyl alcohol (the volatile solvent) is promoted by heating the compressed air and the antimicrobial solution.

  Prior to the suction, the operator controls the characteristic that the plurality of fine particles contact and adhere to the inner surface 16 of the work 14 by adjusting the speed at which the mist passes through the cavity 12 of the work 14. The speed adjustment is performed by adjusting a differential pressure between the pressure in the container 30 and the outlet pressure (for example, the atmospheric pressure) of the suction device 79.

  Thereafter, the work 14 is taken out of the container 30 in step S5.

  Incidentally, an example of the work 14 is a medical cylindrical stent or catheter.

 Stents are a type of medical device.In order to restore the function of locally stenotic or interrupted vessels such as blood vessels and bile ducts in animals such as humans, artificial passages are created in the diseased site. Is to be placed at the diseased site to form it into One example of a stent to which the present invention applies is a biliary plastic stent.

  Stents are classified into plastic and metal when classified by material. The metal stent is, for example, an elastically deformable mesh made of a steel wire. Stents are classified into straight type and pigtail type according to the shape.

  Both types of stents have a common structure that is generally tubular or cylindrical and has an inner surface 16, a lumen (internal passage, through hole) 12 defined by the inner surface 16, and an outer surface 17.

  There are plastic and metal stents. Metal stents are classified into expandable and non-expandable types. The expandable stent is, for example, an elastically deformable mesh made of steel wire. The stent is composed of a shape memory material, for example, Nitinol®, and is desirably manufactured by laser cutting the tube. The stent contracts elastically in the radial direction when a radially inward force is applied in the free or expanded state, and is deployed to the treatment site in the contracted state. When the radial force is released, the stent returns to its free state and spontaneously radially expands (expands).

  The diameter of the inner surface of the stent, that is, the inner diameter, is measured in any state for the plastic stent and the non-expandable metallic stent, both of which do not have expandability, since the inner diameter is always constant. For a metallic stent, since the inner diameter varies depending on the use state, it is measured in an expanded state, that is, a free state.

  According to the present embodiment, both the inner and outer surfaces 16, 17 (only the inner surface 16 is possible) of a work (eg, a stent) 14 having a cavity (eg, a lumen) 12 opened at both ends 18, 19 are formed of a plurality of drug fine particles. Coated. The type of the drug microparticles is selected so as to exhibit, for example, antithrombotic properties, antibacterial properties, and effects such as affinity with blood, body fluids, or living tissues.

  By the way, conventionally, there has been a problem that, after placement of a bile duct plastic stent, bacteria attached to the stent itself form a biofilm, so that the stent is obstructed early and must be replaced. On the other hand, it is already known that silver ions have an antibacterial effect. Furthermore, according to the suction type fine particle coating method developed by the present inventors, even if the inner surface of the stent is thin and narrow or long and narrow, a plurality of drug fine particles can be evenly distributed (at a uniform density). Can be coated.

  Against this background, according to the present embodiment, both the inner and outer surfaces of the biliary plastic stent are coated with a plurality of antimicrobial particles at once. Thereby, the inside and outside double-sided stent for indwelling in the bile duct is obtained.

  Here, the “antibacterial fine particles” are an example of the aforementioned “drug fine particles”, and are also an example of the photocatalytic particles. One example of “antimicrobial particles” is titanium dioxide.

  Further, it is desirable that the “antibacterial fine particles” are used in a state where a plurality of metallic silver particles (for example, silver ions) are supported on the surface thereof. This is because metal silver particles are known to have an effect of improving antibacterial action in cooperation with antibacterial fine particles.

  Some examples of the physical and chemical condition values related to the production of the antibacterial fine particles, the volatile solvent, the antibacterial agent solution and the mist are disclosed in JP-A-2015-171687 of the present applicant. The publications are incorporated herein by reference.

  As described above, the suction device 70 described with reference to FIGS. 3 and 4 is a method of performing suction by contacting (mechanically engaging) with the work 14.

  On the other hand, FIG. 6 shows a non-contact type suction device 110 adopting a method of sucking the work 14 without contacting (mechanically engaging) the work 14.

  The non-contact type suction device 110 generates a jet (jet stream of air), and jets the jet in a direction crossing the second opening end 19 while contacting the second opening end 19 of the work 14.

  Specifically, the non-contact type suction device 110 has a suction port 120 for sucking the mist in the container 30 and a jet port 122 for jetting the sucked mist as a jet.

  Further, the non-contact suction device 110 applies a jet to the second opening end 19 in a direction intersecting with the axis of the work 14, and generates a negative pressure in the second opening end 19 as a Bernoulli effect. It is a jet generator. When the jet acts on the second open end 19 so as to graze the second open end 19, a negative pressure is generated at the second open end 19, and the mist in the cavity 12 is sucked out from the second open end 19.

  According to the suction device 110, the work of contacting and attaching another mechanical component to the work 14 prior to suction is omitted, so that the work efficiency is improved, and adaptation to mass production is facilitated. Since a part of the surface of 14 is covered with the mechanical part, the problem that the antibacterial fine particles do not adhere to that part does not occur.

  According to this embodiment, unlike the case where the work 14 is immersed in the coating liquid to coat the inner surface 16, the mixture of the volatile solvent and the plurality of fine particles is mist-formed and adheres to the inner surface 16 and Is coated, the distribution of fine particles present in the final coat layer (antibacterial layer, antibacterial film) is uniformed, and the coat layer is dried and completed in a short time, shortening the work time The effect is obtained.

  As is clear from the above description, in the example of the suction device 70 shown in FIG. 3, not only the first open end 18 of the work 14 but also the second open end 19 are arranged in the container 30. Is installed outside the container 30.

  In the example of the suction device 70 shown in FIG. 4, not only the first opening end 18 of the work 14 but also the second opening end 19 are arranged in the container 30, and the suction device 70 is installed outside the container 30. The mist discharged from the pump 90 is returned to the container 30 via the external passage (external circulation).

  In the example of the suction device 110 shown in FIG. 6, not only the first opening end 18 of the work 14 but also the second opening end 19 are arranged in the container 30, and the suction device 110 is installed inside the container 30. Further, the mist is circulated in the container 30 (without passing through the external passage) (internal circulation).

  Instead of these examples, the present invention provides that the work 14 penetrates the wall of the container 30 airtightly, the second open end 19 of the work 14 is arranged outside the container 30, and the exposed second open end 19 May be implemented in a mode in which the suction device 70 is suctioned by the suction device 70 disposed outside.

  However, when this mode is adopted, the coating of the outer surface 17 of the same workpiece 14 (for example, the suction type, the normal spraying type, and the normal immersion type proposed this time) is different from the suction type coating of the inner surface 16. May be implemented in the process.

  Here, with reference to FIG. 8, the coating apparatus 10 according to some embodiments described above will be specifically described focusing on a method of sucking mist in the work cavity 12 in the container 30.

  FIG. 8A shows a first specific example of the mist suction method. In this example, it is shown that the mist flows through the cavity 12 as a general laminar flow.

  On the other hand, FIG. 8B shows a second specific example of the mist suction method. In this specific example, it is shown that the mist flows through the cavity 12 as a turbulent flow.

  A turbulence generator 300 is installed between the sprayer 26 and the first open end 18 of the workpiece 14 to turbulate the mist. The turbulence generator 300 is configured to include, for example, a tube 302 that defines an internal passage and an obstacle (typically, a plurality of obstacles) 304 installed on the inner surface of the tube 302. . When the mist collides with the obstacle 304 in the tube 302, the traveling direction of the mist changes irregularly, and as a result, the mist becomes turbulent.

  Here, the obstacle 304 can be, for example, a protrusion, a swash plate extending in a direction intersecting with the axis of the tube 302, or a swirl groove that guides the mist along a spiral path. is there.

  When the mist has a laminar flow, a boundary layer tends to be formed on the inner surface 16 of the work 14, and when the boundary layer is formed, it functions as a barrier standing inside the cavity 12. As a result, the contact of the new mist (new fine particles) with the inner surface 16 of the work 14 is hindered. As a result, the time required until the density of the fine particles attached to the inner surface 16 increases to the target value may be extended.

  On the other hand, when the mist is turbulent, no boundary layer is formed on the inner surface 16 of the work 14, and as a result, the probability that the new mist contacts the inner surface 16 of the work 14 is higher than in the case of the laminar flow. I do. As a result, the time required until the density of the fine particles attached to the inner surface 16 increases to the target value may be reduced. Thereby, the mist is promoted to adhere to the inner surface 16 of the work 14.

  FIG. 8C shows a third specific example of the mist suction method. In this specific example, it is shown that the mist flows in the cavity 12 as a generally reciprocating flow (oscillating flow). The reciprocating flow is turbulent rather than laminar.

  A reciprocating flow generator 400 is used to reciprocate the mist. The reciprocating flow generator 400 also has a function as a suction device. The reciprocating flow generator 400 includes, for example, a cylinder 402 having a shape approximating the nozzle 76, a piston 404 slidably and reciprocally fitted to the cylinder 402, and a rod 406 connected to the piston 404. It is comprised so that it may contain. The rod 406 is an example of a mechanism for converting a rotational movement of a motor (not shown) into a reciprocating movement of the piston 404.

  In FIG. 8C, in section (1), the piston 404 is located at the top dead center when the piston 404 reciprocates relatively to the cylinder 402. In section (2), the piston 404 is located at the bottom dead center when the piston 404 reciprocates relative to the cylinder 402. When the piston 404 moves from the top dead center to the bottom dead center, that is, during the expansion stroke for the cavity 12, the pressure in the cavity 12 of the work 14 increases in the container 30 within the first open end 18 of the work 12. Lower than the pressure at As a result, a forward flow from the first open end 18 to the second open end 19 is generated in the cavity 12, whereby the mist is sucked into the cavity 12 from the internal space of the container 30 and advanced. Mist is sucked by the reciprocating flow generator 400.

  In FIG. 8C, in section (3), the piston 404 is located at the top dead center when the piston 404 reciprocates relative to the cylinder 402. When the piston 404 moves from the bottom dead center to the top dead center, that is, in the compression stroke for the cavity 12, the pressure in the cavity 12 of the work 14 increases in the container 30 within the first open end 18 of the work 12. Rise above the pressure at. As a result, a backward flow from the second open end 19 toward the first open end 18 occurs in the cavity 12, whereby the mist is retreated in the cavity 12.

  In the third specific example shown in FIG. 8C, the same mist is moved forward and backward, that is, reciprocated in the cavity 12, and as a result, the total time that the same mist stays in the cavity 12 is shown in FIG. During c), as shown in sections (1) and (2), the flow of the mist is longer than in the case of a unidirectional flow instead of a reciprocating flow. Thereby, the residence time of each fine particle in the mist is also extended. As a result, the frequency of contact of each fine particle with the inner surface 16 of the work 14 increases, and, of the plurality of fine particles in the mist, the number of fine particles adhered to the inner surface 16 of the work 14 and reaching the purpose increases. As a result, it becomes easy to attach a large number of fine particles to the inner surface 16 of the work 14 for the volume of the mist used.

  In the third specific example shown in FIG. 8C, the piston 404 is located in the cavity 12 of the workpiece 14 at the top dead center. 400 may be redesigned.

  According to some embodiments described above, the inner and outer surfaces of a tubular workpiece having a cavity having a circular cross section are coated at once, but non-circular cross sections (for example, slots, etc., elongated rectangular cross sections, polygonal cross sections, etc.). This embodiment may be implemented to coat only the inner surface of a work having a cavity having a regular cross section, an irregular cross section such as an asymmetric cross section, or to coat both the inner and outer surfaces at once.

  The workpiece may have a shape extending linearly, or may have a shape extending nonlinearly, for example, in a curved line.

  Further, the work may be one used in an industry other than the medical industry, for example, a work used for an industrial product or component.

  Further, in some embodiments described above, the work 14 is hollow, and at least the inner surface 16 of the work 14 is coated by suction. However, in this suction coating method, the work 14 is solid. Alternatively, the present invention may be applied to only the outer surface 17 of the work 14 irrespective of whether the work 14 is hollow or solid.

  In some embodiments described above, an electrostatic coating method may be performed in addition to or instead of the suction coating method.

  According to the electrostatic coating method, for example, under the electric field in which the fine particles are negatively charged and the work 14 is positively charged, the charges of different polarities, that is, the fine particles and the work 14 are electrostatically attracted to each other. I do. In this electrostatic coating method, when compared with the aforementioned suction, the aforementioned suction is suction using a pressure difference, whereas this electrostatic suction is suction using a difference in polarity. (It is different from spraying, pushing, pushing).

  In some embodiments described above, the suction device 70 is exclusively used for sucking the internal volume existing in the cavity 12 of the work 14 from the second open end 19 of the mist.

  That is, while the purpose is to coat the inner and outer surfaces 16 and 17 of the work 14 at once, the internal space of the container 30 in which the work 14 is accommodated is not entirely sucked but the cavity 12 of the work 14 is Only the space inside is sucked, and as a result, the pressure is distributed in the container 30 so that the pressure in the cavity 12 of the work 14 is lower than the space outside the work 14.

  However, instead of this, at the same time that the internal volume is sucked from the second opening end 19, the external volume existing outside the outer surface 17 of the work 14 is removed from the position near the second opening end 19 of the mist. The suction device 70 may be redesigned to be used for suction.

  The suction device 110 shown in FIG. 6 is used for sucking the internal volume from the second opening end 19 and simultaneously suctioning the external volume from a position near the second opening end 19.

  Further, in some embodiments described above, the work 14 is accommodated in the container 30 so that both the first open end 18 and the second open end 19 are separated from the inner wall surface of the container 30 to the inside. On the other hand, the present invention is applied to the embodiment in which the workpiece 14 is accommodated in the container 30 only in the first open end 18, only the second open end 19, or in any state in which the work 14 penetrates the wall of the container 30. May be implemented.

  As described above, some of the exemplary embodiments of the present invention have been described in detail with reference to the drawings. However, these are merely examples, and the embodiments described in the “Summary of the Invention” section may be used by those skilled in the art. The present invention can be implemented in other forms in which various modifications and improvements are made based on knowledge.

Claims (4)

A method of coating at least the inner surface of the inner and outer surfaces of the work having a cavity opened at both ends with a plurality of fine particles,
A holding step of holding the work so that at least the first open end of the first open end and the second open end of the work is located in the container;
A sprayer, a mist generating step of spraying a solution composed of the plurality of fine particles mixed in a volatile state in a volatile solvent together with a compressed gas to generate a mist,
Applying the generated mist to a first opening end of the work;
A suction device for sucking a part of the mist introduced into the cavity of the work from a second opening end of the work by a suction device;
An inner surface adhesion promoting step of promoting the plurality of fine particles to adhere to the inner surface of the work,
The inner surface adhesion promotion step is
A turbulence generator, which turbulences the mist generated in the mist generation step and introduces the turbulent mist into the cavity from the first opening end;
A suction type fine particle coating method for performing at least one of a reciprocating flow step of reciprocating a mist introduced into the cavity from the first opening end by a reciprocating flow generator. further,
When the pressure of the mist in the container is to exceed a preset relief pressure, a pressure regulating step of opening a relief valve and allowing a part of the mist to flow out of the container,
In order to coat the inner and outer surfaces of the work at once, by installing the relief valve in the container at a position closer to the second opening end than the first opening end, in the container, to the mist, An outer surface adhesion promoting step of generating a flow from the first opening end toward the second opening end along the outer surface of the work, thereby promoting the plurality of fine particles to adhere to the outer surface of the work. The suction-type fine particle coating method according to claim 1, comprising: An apparatus for coating the inner surface of a tubular work having a cavity opened at both ends with a plurality of fine particles or coating the inner and outer surfaces of the work with a plurality of fine particles at once,
A container,
A holder for holding the work so that at least the first open end of the first open end and the second open end of the work is located in the container;
A sprayer for spraying a mist into the container by spraying a solution formed by mixing the plurality of fine particles in a volatile solvent in a dispersed state together with a compressed gas,
A suction device that is applied to a second opening end of the work and suctions a part of the mist introduced into the cavity of the work from the second opening end;
An inner surface adhesion promoting device that promotes the plurality of fine particles to adhere to the inner surface of the work,
The inner surface adhesion promotion device is
A turbulence generator that turbulates the mist generated by the sprayer and introduces the turbulent mist into the cavity from the first opening end;
A reciprocating flow generator configured to reciprocate the mist introduced into the cavity from the first opening end. further,
Including a relief valve that opens when the pressure of the mist in the container exceeds a preset relief pressure to allow a part of the mist to flow out of the container,
The relief valve is disposed on the container at a position closer to the second opening end than the first opening end, whereby the mist is provided in the container along the outer surface of the work in the mist. 4. The suction-type fine particle coating apparatus according to claim 3, wherein a flow is generated from an end toward the second opening end, thereby promoting adhesion of the plurality of fine particles to an outer surface of the work. 5.

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