JP2019058863A - Electrostatic spray method and electrostatic spray device suitable for electrostatic spray method - Google Patents

Abstract

To provide an electrostatic spray method capable of suitably coating an inside surface with a liquid when coating the coating object being cylindrical and having through-holes with the liquid in a longitudinal direction and being formed with the plurality of through-holes penetrating from an outside surface to an inside surface stipulating the through-holes on a side wall.SOLUTION: An electrostatic spray method capable of suitably coating an inside surface with a liquid when coating the outside surface of a coating object 50 being cylindrical and having through-holes 50H in a longitudinal direction with the liquid and being formed with the plurality of through-holes penetrating from an outside surface to an inside surface stipulating the through-holes 50H on a side wall includes: a step arranging the attraction electrodes 30 of an electrostatic spray device 10 in the through-holes 50H of the coating object 50; and a step spraying the liquid to the coating object 50 by applying a voltage generating an electrostatic force spraying the liquid from a nozzle 22 only with the electrostatic force between the coating object 50 and a liquid spray part 20 having the attraction electrodes 30 and the nozzle 22 of the electrostatic spray device 10 while keeping the coating object 50 and the attraction electrodes 30 in a same potential.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an electrostatic spraying method and an electrostatic spraying device suitable for use in the electrostatic spraying method.

Patent Document 1 discloses a method for coating a surface such as a stent and an apparatus used therefor.
In this patent, coating is performed while the nozzle of the dispenser is positioned along the outer surface of the reticulated stent.

JP, 2009-240490, A JP, 2015-192961, A

However, it is very laborious to coat the nozzle of the dispenser so that the nozzle of the dispenser is located along the outer surface of the very small mesh-like stent, and it has a tubular shape with through holes in the longitudinal direction like a stent. And the appearance of a method of forming a coating by simply applying a liquid to the outer surface of a substrate having a plurality of holes formed in the side wall from the outer surface to the inner surface defining the through hole is desired. There is.
In addition, when applying the liquid, it is desirable that the application state of the liquid to be applied to the inner surface can also be appropriate (for example, the state where the liquid is not applied to the inner surface or the state where the coating film has a predetermined film thickness) .

In addition, as a thing which sprays a liquid only to a fine place using electrostatic force, there exists a thing like patent document 2. FIG.
However, as far as the present inventors know, when liquid is applied to a stent or the like by a spraying method in which the liquid is sprayed using only such electrostatic force, the application state of the liquid applied to the inner surface is also appropriate. I have not found anything that can be done.

  The present invention has been made in view of such circumstances, and is simply a tubular shape having a through hole in the longitudinal direction like a stent, and penetrates from the outer surface to the inner surface defining the through hole in the side wall Suitable for use in the electrostatic spraying method and the electrostatic spraying method which can make the liquid application state to the inner surface suitable as well when the liquid is applied to the outer surface of the substrate having a plurality of holes formed thereon. To provide an electrostatic spray device.

The present invention is grasped by the following composition in order to achieve the above-mentioned object.
(1) The electrostatic spray method according to the present invention is a cylindrical object having a through hole in the length direction, and a plurality of holes formed in the side wall from the outer surface to the inner surface defining the through hole. An electrostatic spray method capable of appropriately applying a liquid to the inner surface when applying the liquid to the outer surface of the electrode, wherein the conductive or semiconductive adsorption electrode of the electrostatic spray device is A step of disposing the object in the through hole of the object to be coated, a liquid spray unit having the object to be coated, the adsorption electrode, and the nozzle of the electrostatic spray device while maintaining the object to be coated and the adsorption electrode at the same potential. Applying a voltage to generate the electrostatic force to spray the liquid from the nozzle only by the electrostatic force between the nozzles to spray the liquid toward the object.

(2) In the configuration of the above (1), the adsorption electrode is disposed in the through hole of the article so as not to contact the inner surface of the article.

(3) In the configuration of the above (1) or (2), the object to be coated is a stent in which the side wall has a mesh shape, and the liquid is a biodegradable and absorbable polymer which is decomposed and absorbed in a solvent by a solvent. It is melted.

(4) In the configuration of any one of the above (1) to (3), the adsorption electrode which is a separation distance between the adsorption electrode whose inner surface is not coated with the liquid and the inner surface is used.

(5) The electrostatic spray device according to the present invention is a cylindrical object having a through hole in the length direction, and a plurality of holes formed in the side wall from the outer surface to the inner surface defining the through hole. An electrostatic spray device capable of appropriately applying a liquid to the inner surface when applying the liquid to the outer surface of the liquid, wherein the electrostatic spray device includes a liquid spray portion having a nozzle; The electrostatic force, which is disposed in the through hole and sprays the liquid by the electrostatic force only from the nozzle, while making the potentials of the conductive or semiconductive adsorption electrode, the object to be coated, and the adsorption electrode the same. And a voltage application unit that applies a voltage generated between the object to be coated and the adsorption electrode and the liquid spray unit between the object to be coated and the adsorption electrode and the liquid spray unit.

(6) In the configuration of the above (5), in the adsorption electrode, the size of the cross section of the portion disposed in the through hole of the article is not in contact with the through hole of the article is there.

(7) In the configuration of the above (5) or (6), a length of the adsorption electrode is longer than a length of the object to be coated.

(8) In the configuration according to any one of the above (5) to (7), in the adsorption electrode, the size of the cross section of the portion disposed in the through hole of the article is the liquid on the inner surface It is a magnitude | size which becomes the separation distance between the said adsorption electrode and the said inner surface for not apply | coating.

  According to the present invention, an object to be coated is simply a tubular having a through hole in the longitudinal direction like a stent and having a plurality of holes formed in the side wall from the outer surface to the inner surface defining the through hole. The present invention can provide an electrostatic spraying method capable of appropriately applying the liquid on the inner surface when applying the liquid to the outer surface of the above, and an electrostatic spraying device suitable for use in the electrostatic spraying method. .

It is a perspective view for demonstrating the electrostatic spraying apparatus of 1st Embodiment which concerns on this invention. It is sectional drawing which showed only the liquid spraying part of 1st Embodiment concerning this invention. It is an expanded sectional view of the tip side of the liquid spraying part of FIG. 2, (a) is a case where the tip surface of a mandrel is located back, (b) is a tip surface of a mandrel front rather than the state of (a). In the case of It is the top view which showed only the adsorption | suction electrode of 1st Embodiment which concerns on this invention, a support part, a holding part, and a to-be-coated-article. It is the perspective view which showed only the adsorption | suction electrode of 1st Embodiment which concerns on this invention, a support part, a holding part, and a to-be-coated-article. It is a figure for demonstrating the state when the liquid sprayed from the nozzle of 1st Embodiment which concerns on this invention applies to a to-be-coated-article, (a) is provided with an adsorption electrode in a to-be-coated-article. It is a figure which shows a case and (b) is a figure which shows the case where the adsorption electrode is not provided in the to-be-coated-article.

Hereinafter, with reference to the accompanying drawings, modes (hereinafter, embodiments) for carrying out the present invention will be described in detail.
In addition, the same number or code | symbol is attached | subjected to the same element through the whole description of embodiment.

  Moreover, unless otherwise noted, expressions such as “front (end)” and “front (front)” indicate the spray direction side of the liquid in each member etc., and “rear (end)” and “rear (front)” The expression such as "represents the opposite side of the liquid spray direction in each member or the like.

First Embodiment
FIG. 1 is a perspective view for explaining an electrostatic spraying device 10 according to a first embodiment of the present invention.
In the present embodiment, a substrate 50 having a through hole 50H (see FIG. 5) in the length direction, and a plurality of holes penetrating from the outer surface to the inner surface defining the through hole 50H in the side wall As a representative example of the case of a medical stent having a cylindrical through-hole 50H in the longitudinal direction and a reticulated sidewall as an example, liquid is not applied to the inner surface of the stent while the liquid is applied to the outer surface. Will be described to form a coating on the outer surface of the stent.

For example, in the case of a coronary artery stent for medical use, the inner diameter is about 2.25 mm or more and 4.00 mm or less, the outer diameter is 2.75 mm or more and 4.50 mm or less (that is, the thickness of the material forming the stent is about 0.25 mm) And the length is about 8.00 mm or more and 38.00 mm or less, which is very fine.
However, in the drawings, the object to be coated 50 (medical stent), the adsorptive electrode 30 and the like are described larger than the liquid spray unit 20 so that the state of the stent or the like can be easily understood.

  When a coating is formed on the outer surface of such a medical stent, as the liquid used, one obtained by dissolving a biodegradable and absorbable polymer which is decomposed and absorbed in vivo in a solvent is used, and a biodegradable and absorbable polymer is used. As typical examples of poly-L-lactic acid (PLLA), poly-DL-lactic acid (PDLLA) and polycaprolactone (PCL), it is not necessary to be limited to these.

  The object to be coated 50 is not limited to a medical stent, but is cylindrical in shape having through holes 50H in the length direction, and penetrates from the outer surface to the inner surface defining the through holes 50H in the side wall. It is sufficient that the holes are formed, and in this case, the liquid to be used is also matched to the substrate 50 and a liquid such as a paint is used.

As shown in FIG. 1, the electrostatic spray device 10 includes a liquid spray unit 20 having a nozzle 22, a conductive or semiconductive adsorption electrode 30 having a surface resistance of 10 ¹⁰ Ω or less, an object to be coated 50 and adsorption And a voltage application unit that applies a voltage between the electrode and the liquid spray unit.

The voltage application means 40 includes a voltage power supply 41, a first electric wiring 42 electrically connecting one of the electrodes of the voltage power supply 41 and the liquid spray unit 20, and an adsorption electrode 30 so that the adsorption electrode 30 can rotate and slide. A conductive support portion 43 having a receiving portion 43a for receiving one end side and supporting the suction electrode 30, and a second electric wire 44 electrically connecting the other electrode of the voltage power supply 41 and the support portion 43. And a holding portion 45 which rotatably holds the adsorption electrode 30 and the object to be coated 50 and electrically connects the adsorption electrode 30 to the object to be coated 50 (sometimes referred to as a short circuit).
The holder 45 will be described in detail later.

  Then, the adsorptive electrode 30 is disposed so as to be in contact with the support portion 43 electrically connected to the other electrode of the voltage power supply 41 by the second electrical wiring 44, whereby the support portion 43 and the adsorptive electrode 30 are The short-circuited state and the adsorptive electrode 30 and the object to be coated 50 are in the shorted state by the holding portion 45, so that the voltage between the adsorptive electrode 30 and the object to be coated 50 and the liquid spray portion 20 is When applied, the object 50 and the adsorption electrode 30 have the same potential.

Therefore, the voltage application means 40 applies a voltage between the object to be coated 50 and the adsorption electrode 30 and the liquid spray section 20 while keeping the object to be coated 50 and the adsorption electrode 30 at the same potential.
However, the voltage application means 40 applies a voltage between the object to be coated 50 and the adsorption electrode 30 and the liquid spray unit 20 while maintaining the object to be coated 50 and the adsorption electrode 30 at the same potential. What is necessary.

In the present embodiment, the electrostatic spraying device 10 is provided with the grounding means 46, and the second electric wiring 44 is connected to the grounding means 46, so the object 50 and the adsorption electrode 30 are in the state of being grounded. It has become.
Although the grounding means 46 is not an essential requirement, the work 50 may be touched by the worker, so the grounding means 46 is provided to ground the work 50 from the viewpoint of safety. Is preferred.

  Then, later, how the liquid is sprayed will be described, but the voltage application means 40 sets the potential of the object to be coated 50 and the adsorption electrode 30 to the first potential which is the same potential. Assuming that the electric potential is a second electric potential, the electric potential difference between the first electric potential and the second electric potential is an electrostatic force that sprays the liquid from the nozzle 22 only by the electrostatic force between the object 50 and the adsorption electrode 30 and the liquid spray portion 20 A voltage is applied between the object to be coated 50 and the adsorption electrode 30 and the liquid spray unit 20 so as to have a potential difference sufficient to generate the voltage.

(Liquid spray part)
FIG. 2 is a cross-sectional view showing only the liquid spray unit 20, and the liquid spray unit 20 illustrates the state where the liquid is sprayed as described later.

  As shown in FIG. 2, the liquid spray unit 20 includes a body portion 21 made of an insulating material and a liquid flow path 21 b having a liquid supply port 21 a to which the liquid is supplied. A nozzle 22 provided at the tip of the body 21 so as to communicate with the passage 21 b; and a mandrel 23 made of a conductive material disposed in the liquid flow path 21 b of the body 21 and in the through hole of the nozzle 22 There is.

The body portion 21 is provided with a hole 21c communicating with the liquid flow passage 21b in order to take out the mandrel 23 to the rear end side, and in the hole 21c, a gap with the mandrel 23 is sealed. A sealing member 24 is provided to prevent the liquid from leaking.
In the present embodiment, an O-ring is used as the seal member 24. However, the seal member 24 is not limited to the O-ring, and any seal may be used.

  A knob 23a made of an insulating material is provided at the rear end of the stem 23 located on the rear end side of the body 21 through the hole 21c, and is provided to penetrate substantially the center of the knob 23a. An electrical wiring connection 23b made of the conductive material is provided.

  As shown in FIG. 1, the first electric wiring 42 of the voltage application means 40 is connected to the electric wiring connection portion 23b, and the electric wiring connection portion 23b is brought into contact with the mandrel 23. The wiring connection portion 23 b is electrically connected.

  In the present embodiment, the mandrel 23 is used as an electrode on the liquid spray unit 20 side. However, for example, assuming that the nozzle 22 of the liquid spray unit 20 is made of a conductive material, the first electric The wire 42 may be connected, and the nozzle 22 may be an electrode on the liquid spray unit 20 side.

  Further, as shown in FIG. 2, a female screw structure 21e for screwing and connecting the knob 23a is provided on the inner peripheral surface of the rear end opening 21d of the body 21. On the other hand, the tip of the knob 23a A male screw structure 23c is provided on the outer peripheral surface.

Therefore, the mandrel 23 is removably attached to the body portion 21 by screwing the external thread structure 23c of the tip outer peripheral surface of the knob portion 23a with the internal thread structure 21e of the rear end opening 21d of the body portion 21.
Further, by adjusting the screwing amount of the knob portion 23a, the mandrel 23 can be moved in the front-rear direction, and the position of the tip surface 23d of the mandrel 23 can be adjusted in the front-rear direction.

  In addition, since it is difficult to make the opening 22b of the nozzle 22 too large in diameter in order to spray the liquid well only by electrostatic force, clogging may occur. Can be moved in the back and forth direction, so that even if clogging occurs in the nozzle 22, the clogging can be eliminated by moving the mandrel 23.

  FIG. 3 is an enlarged view of the tip end side of the liquid spray unit 20, and FIG. 3 (a) is a case where the tip end face 23d of the mandrel 23 is located rearward, FIG. 3 (b) is FIG. This is the case where the tip end face 23d of the mandrel 23 is positioned forward of the state of (a).

  As shown in FIG. 3A, the nozzle 22 has a tapered inner diameter portion (see the range W1) with a taper angle α, the inner diameter of which decreases in a tapered manner toward the opening 22b side. Has a tapered portion (see the range W2) in which the taper angle at which the outer diameter decreases toward the end face 23d is β.

The taper angle α of the tapered inner diameter portion of the nozzle 22 is made larger than the taper angle β of the tapered portion of the mandrel 23.
The diameter of the end face 23d of the stem 23 is smaller than the diameter of the opening 22b of the nozzle 22, but the tapered portion of the stem 23 has a gradually larger diameter toward the rear end. And has a portion with a diameter larger than the diameter of the opening 22 b of the nozzle 22.

  As described above, by forming the tip end side of the nozzle 22 and the mandrel 23, as shown in a comparison of FIGS. 3A and 3B, the nozzle 22 and the mandrel 22 are moved in the front-rear direction. The width of the gap formed by the mandrel 23 can be adjusted, and the amount of liquid exiting the opening 22 b of the nozzle 22 can be adjusted.

Further, by moving the mandrel 23 further forward than in the state shown in FIG. 3B, the mandrel 23 can abut on the inner peripheral surface of the nozzle 22, and the opening 22b of the nozzle 22 can be closed. It is.
Therefore, in the state where the liquid is not sprayed, the opening 22 b of the nozzle 22 can be closed by the mandrel 23 to prevent the liquid in the nozzle 22 from being dried, and therefore clogging of the nozzle 22 can be suppressed.

(Basic spray condition of liquid)
Next, with reference to FIG. 2, first, a basic state in which the liquid is sprayed from the liquid spray unit 20 will be described, and then a state in which the liquid 50 is applied to the object 50 will be described.

  The liquid supplied to the liquid supply port 21 a of the body portion 21 is supplied to the tip end side of the nozzle 22, and the voltage application means 40 (see FIG. 1) Only the electrostatic force between the object to be coated 50 and the adsorbing electrode 30 and the mandrel 23 generated by the voltage applied to it is pulled forward to be detached and atomized forward.

  The state in which the liquid separates and atomizes will be described more specifically. As shown in FIG. 2, the adhesion by the surface tension and viscosity of the liquid to the tip end surface 23d of the mandrel 23 and the tip outer peripheral edge 22a of the nozzle 22 On the other hand, the electrostatic force pulling the liquid forward balances, whereby the liquid supplied to the tip side of the nozzle 22 forms a tailor cone 60 having a conical shape at its tip.

In the tailor cone 60, positive / negative charge separation occurs in the liquid by the action of the electric field, and the meniscus of the tip of the nozzle 22 charged with excess charge is deformed and formed in a conical shape.
Then, the liquid is pulled straight from the tip of the tailor cone 60 by electrostatic force, electrostatic explosion occurs at the tip, and the liquid is detached / atomized, that is, sprayed.

  The sprayed liquid, that is, the liquid separated from the nozzle 22 to become liquid particles has a dramatically larger area in contact with air compared to the state before separation, so the vaporization of the solvent is promoted, and the solvent is With vaporization, the distance between the charged electrons approaches, and electrostatic repulsion (electrostatic explosion) occurs to break up into liquid particles of smaller particle size.

When this split occurs, the surface area exposed to air further increases compared to that before the split, so the vaporization of the solvent is promoted, the electrostatic explosion occurs as described above, and the liquid with a smaller particle size is further generated. It breaks up into particles.
As described above, the liquid sprayed from the nozzle 22 by electrostatic explosion is further repeatedly atomized after atomization, whereby atomization is further promoted and applied to the substrate 50 in the form of extremely small particles. become.

  Next, after describing the configuration of the electrostatic spray device 10 on the side of the object 50, as described above, the state in which the liquid sprayed from the nozzle 22 is applied to the object 50 will be described. .

FIG. 4 is a plan view showing only the adsorption electrode 30, the support portion 43, the holding portion 45 and the object 50, and FIG. 5 shows only the adsorption electrode 30, the support portion 43, the holding portion 45 and the object 50 FIG.
FIG. 4 is a plan view seen from the upper side.

  As shown in FIGS. 4 and 5, the support portion 43 has a first main portion 43A formed with a receiving portion 43a formed of a U-shaped notch opened upward, and both sides of the first main portion 43A. A pair of first mounting portions 43B are provided to project from the first main body 43A, and have screw holes 43b for passing screws when screwing onto a mounting table (not shown).

  Further, as shown in FIG. 4 and FIG. 5, the holding unit 45 holds the adsorption electrode 30 and the object to be coated 50, and is provided with a second rotation holding unit 45 a that rotates with the adsorption electrode 30 and the object to be coated 50. A main body 45A and screw holes 45b are formed on both sides of the second main body 45A so as to protrude from the second main body 45A, and screw holes 45b for passing screws when screwing onto a mounting table (not shown) are formed. And a pair of second attachment portions 45B.

Then, as shown in FIG. 1, when the holding portion 45 holds the suction electrode 30, the positional relationship is such that one end side of the suction electrode 30 can be received by the receiving portion 43a of the support portion 43. The support portion 43 and the holding portion 45 are fixed by screws on the mounting table (not shown) so that the support portion 43 and the holding portion 45 are positioned.
In addition, an insulating material is used for the part to which the support part 43 and the holding part 45 of a mounting base which are not shown in figure are fixed.

The rotation holding portion 45a is fixed to the bearing portion 45aa (for example, a ball bearing) fixed at the center of the second main body portion 45A and the first through hole 45H1 at the center of the bearing portion 45aa by press fitting or the like. A cylindrical fitting portion 45ab having a second through hole 45H2 to be fitted and a first holding body 45ac provided on the other side of the fitting portion 45ab and holding the object 50 are provided.
Since the fitting portion 45ab is formed of a conductive material, the suction electrode 30 is fitted to the fitting portion 45ab, and the fitting portion 45ab and the suction electrode 30 are brought into contact with each other, whereby the fitting portion 45ab is formed. Is in a state electrically connected to the adsorption electrode 30 (sometimes referred to as a short circuit).

  As shown in FIG. 4, the fitting portion 45 ab is provided so as to penetrate the second main body portion 45A when viewed from above as viewed from above, and the fitting portion 45 ab protrudes from the second main body portion 45A to one side An end surface 45ab1 of the joint portion 45ab serves as a receiving surface for receiving a position control portion 31a of a suction electrode 30, which will be described later.

  Further, the fitting portion 45ab has an annular step along the outer periphery of the second through hole 45H2 in which the suction electrode 30 is fitted to the end surface 45ab2 of the fitting portion 45ab which protrudes from the second main body portion 45A to the other side. A cylindrical first holding body 45ac formed of an insulating material for holding one side of the through hole 50H (see FIG. 5) of the object 50 is press-fitted or the like in the step portion. It is fixed.

The diameter (sometimes referred to as the inner diameter) of the central third through hole in the first holding body 45ac is substantially the same as the diameter (sometimes referred to as the inner diameter) of the second through hole 45H2 (see FIG. 5) of the fitting portion 45ab. It has the same diameter.
Further, the first holding body 45ac has an outer diameter smaller than the outer diameter of the fitting portion 45ab. Specifically, the first holding body 45ac has a diameter of the through hole 50H of the object 50 (referred to as an inner diameter In some cases, the outer diameter is approximately equal to or slightly larger.

The first holding body 45ac is fixed to the fitting portion 45ab so that the central axis of the third through hole is coaxial with the central axis of the second through hole 45H2 of the fitting portion 45ab.
Specifically, as described above, the first holding body 45ac is formed on the other end surface 45ab2 of the fitting portion 45ab from the other end surface 45ab2 of the fitting portion 45ab to the other side The outer diameter of the first holding body 45ac is smaller than the outer diameter of the fitting portion 45ab.

  Although the reason will be described later, the amount of projection (protrusion length) from the end face 45ab2 of the other side of the fitting portion 45ab of the first holding body 45ac is the minimum necessary for holding the object 50. It has a length.

  Therefore, the end surface 45ab2 of the other side of the fitting portion 45ab exists on the outer periphery of the first holding body 45ac, and the end 50a of the object 50 on one side is the end surface 45ab2 of the other side of the fitting portion 45ab. When the object 50 is mounted on the rotary holding portion 45a so that the first holding body 45ac is inserted into the through hole 50H of the object 50 until it comes into contact with the object 50, the fitting portion 45ab Since it is formed of a conductive material, the adsorptive electrode 30 fitted to the fitting portion 45ab and the object to be coated 50 are shorted through the fitting portion 45ab.

  On the other hand, the adsorption electrode 30 is provided on one side, and the first rod portion 31 having an outer diameter larger than the diameter of the second through hole 45H2 of the fitting portion 45ab and the other end surface of the first rod portion 31 And extends from the other end face of the second rod portion 32 to the other side, the second rod portion 32 having an outer diameter substantially equal to the diameter of the second through hole 45H2 of the fitting portion 45ab. And a third rod-like portion 33 having an outer diameter smaller than the diameter of the through hole 50H of the paint 50.

  Since the outer diameter of the second rod-shaped portion 32 is smaller than that of the first rod-shaped portion 31, the other end surface of the first rod-shaped portion 31 exists on the outer periphery of the second rod-shaped portion 32. A position where the end face abuts on the end face 45ab1 of the fitting portion 45ab to regulate the insertion position when the adsorption electrode 30 is inserted into the second through hole 45H2 in order to fit the suction electrode 30 into the fitting portion 45ab It functions as the regulation part 31a.

Further, in the present embodiment, the electrostatic spray device 10 is provided with the second holding body 47 which is attached to the other end of the suction electrode 30 and is made of an insulating material for holding the object 50 to be coated. .
Specifically, the second holding body 47 has a holding end portion 47a having an outer diameter which is substantially equal to or slightly larger than the diameter of the through hole 50H of the object 50, and the other end of the holding end portion 47a. And a stopper 47b extending from the side and having an outer diameter larger than the outer diameter of the holding end 47a and the diameter of the through hole 50H of the object 50.

The stopper 47b abuts on the other end 50b of the object 50 to stop the movement of the object 50 to the other side, and a gap between the adsorption electrode 30 and the object 50. Perform the function of keeping
Further, although the reason will be described later, the protrusion amount (length) of the holding end portion 47 a from the stop portion 47 b is set to a minimum length necessary to hold the object 50.

  The second holding body 47 has a fourth through hole 47 c having a diameter substantially equal to the outer diameter of the third rod-like portion 33 of the suction electrode 30 at the center, and is fitted to the third rod-like portion 33. It can be fixed.

Therefore, after the suction electrode 30 and the object 50 are held by the rotary holding portion 45a, the other end of the object 50 is further held so that the holding end 47a of the second holding member 47 holds the object 50. The second holding body 47 is fitted to the third rod-like portion 33 of the suction electrode 30 while the holding end portion 47a of the second holding body 47 is inserted into the through hole 50H from the side, and the second holding body 47 is It can be fixed to 30. When fixed in this manner, the object to be coated 50 is held by the holding portion 45 so as to be rotatable together with the suction electrode 30, as shown in FIG.
As described above, when the second holding body 47 is fixed to the suction electrode 30, the stopper portion 47b of the second holding body 47 is brought into contact with the other end 50b of the article 50.

  By the way, although the reason will be described later, the outer diameter of the third rod-like portion 33 of the adsorptive electrode 30 to be positioned in the through hole 50H of the object 50 is determined by the diameter of the through hole 50H of the object 50 More specifically, the size of the cross section of the third rod-like portion 33 is limited to a size that can be disposed in the through hole 50H so as not to contact the through hole 50H of the object 50 sufficiently.

  For example, the outer diameter of the third rod-like portion 33 of the adsorption electrode 30 is a through hole of the object 50 so as to form a gap with the object to be coated 50 or more than the thickness of the liquid attached to the object 50. The diameter is reduced by 0.1 mm or more with respect to the diameter of 50 H so that the object 50 is not caught when the adsorption electrode 30 is pulled out.

However, as the outer diameter of the third rod-like portion 33 of the adsorption electrode 30 is made smaller, it can be understood that the adsorption electrode gradually approaches the same state as when the third rod-like portion 33 of the adsorption electrode 30 is absent. When the outer diameter of the third rod-like portion 33 of 30 is too small and the separation distance between the third rod-like portion 33 of the adsorption electrode 30 and the inner surface of the through hole 50H of the substrate 50 becomes too large, the substrate The liquid is applied to the inner surfaces of the 50 through holes 50H.
For this reason, the outer diameter of the third rod-like portion 33 of the adsorption electrode 30 is set so as to be small enough to prevent the liquid from being applied to the inner surface of the through hole 50H of the object 50 to be coated.

Next, a state in which the liquid sprayed from the nozzle 22 is applied to the article 50 will be described.
FIG. 6 is a view for explaining a state in which the liquid sprayed from the nozzle 22 is applied to the object 50. FIG. 6 (a) shows the adsorption electrode 30 (more specifically, in the object 50). In particular, FIG. 6 (b) shows the case where the adsorption electrode 30 (more specifically, the third rod-like portion 33) is provided in the object 50. It is a figure which shows the case where there is no.

  In FIG. 6, the trajectory L of the liquid particles sprayed from the nozzle 22 up to the object to be coated 50 is schematically shown by a solid line and a dotted line, and the solid line indicates the sidewall of the stent or the like which is the object to be coated 50. Is the trajectory L of the liquid particle that travels towards the position of the hole that penetrates the interior, and the dotted line is the trajectory L of the liquid particle that proceeds to collide with the outer surface of the sidewall of the stent or the like.

As described above, since the liquid is so strongly charged that it is sprayed from the nozzle 22 by electrostatic explosion, the liquid is strongly attracted to the object 50 by the electrostatic force.
For example, as shown in FIG. 6, even liquid particles having passed through the left and right outer sides (upper and lower outer sides in the state of FIG. 1) in FIG. 6 of the article 50 can be drawn to the back side of the article 50 The liquid particles are strongly attracted to the substrate 50 side.

  Therefore, the liquid can be applied to the entire circumferential direction of the side wall of the article 50 without rotating the article 50, but the entire circumferential direction of the side wall of the article 50 can be coated. In the present embodiment, by rotating the rotation holding portion 45a (see FIG. 4), the liquid is applied to the object 50 while rotating the adsorption electrode 30 and the object 50 in order to apply the liquid uniformly to the I am trying to apply it.

  Specifically, the rotational force of the rotation shaft of the motor is transmitted to the fitting portion 45 ab so that the rotational shaft of the motor and the fitting portion 45 ab of the rotation holding portion 45 a are connected by a belt. The holding electrode 45 and the object 50 are rotated by rotating the holding portion 45a.

  However, the method of rotating the rotation holding portion 45a is not limited to the transmission of the rotational force of the motor by the belt, and may be transmitted by a gear or the like, and the power source for generating the rotational force is the motor It may be other than.

  On the other hand, some of the liquid particles that are vigorously attracted to the side of the object 50 are directed toward the position of the through-hole in the side wall, and such liquid particles pass through the through-hole. And intrude into the inside of the article 50.

  Since the liquid particles thus invading the inside of the article 50 are also attracted to the side of the article 50 by the electrostatic force, as shown in FIG. 6 (b), the adsorption electrode 30 (in the article 50) More specifically, if the third rod-like portion 33) does not exist, it is applied to the inner surface of the substrate 50.

  On the other hand, as shown in FIG. 6A, the adsorption electrode 30 (more specifically, the third rod-like portion 33) maintained at the same potential as the object 50 is present in the through hole 50H of the object 50 Then, since the adsorption electrode 30 itself becomes a target to which the liquid particles are applied in the same manner as the substrate 50, the liquid particles that have passed through the holes in the side wall are adsorbed by the adsorption electrode 30, and the inner surface of the substrate 50 It is suppressed to apply to.

  Further, as described above, since the adsorption electrode 30 is not in contact with the inner surface of the coated object 50, when the adsorption electrode 30 is removed after the liquid spraying operation is completed, the adsorption electrode 30 is used. It can also be avoided that the adsorbed liquid adheres to the inner surface of the article 50.

  Furthermore, generation of a spark between the to-be-coated article 50 and the adsorptive electrode 30 located close to each other can be avoided because the to-be-coated article 50 and the adsorptive electrode 30 are at the same potential.

On the other hand, as described above, since the second holding body 47 and the first holding body 45ac are formed of the insulating material, the surface is also charged by the generated electrostatic force, and the charged liquid particles are repelled. It is in the state of
For this reason, in the portion where the first holding body 45ac and the holding end portion 47a of the second holding body 47 are inserted into the article 50, the liquid particles directed to the holes of the article 50 have their repulsive force. It will be pushed back.

  However, even if it is formed of an insulating material, the liquid particles may not be repelled well depending on the conditions such as humidity, and the liquid particles are applied to the first holding body 45 ac and the holding end 47 a of the second holding body 47. Then, since the liquid adheres to the inner surface of the object 50 when the object 50 is removed, as described above, the holding end portions 47 a of the first holding body 45 ac and the second holding body 47 are: Only the minimum length necessary to hold the object 50 is fixed.

  If there is a portion where the length of the adsorption electrode 30 is short and the adsorption electrode 30 does not exist when viewed in the length direction of the coated object 50, the portion where the adsorption electrode 30 does not exist is shown in FIG. The adsorption electrode 30 preferably has a length longer than that of the object 50 because the liquid adheres to the inner surface of the object 50 in a state similar to that shown.

  As described above, in the adsorption electrode 30 of the present embodiment, the outer diameter of the portion of the adsorption electrode 30 disposed in the through hole 50H of the coated object 50 is such that the liquid is not applied to the inner surface of the coated object 50. The outer diameter is set such that the distance between the adsorption electrode 30 and the inner surface of the object 50 is reduced.

  As in the present embodiment, when the object 50 is a medical stent, the through hole 50H is circular, but when the object 50 is other than a stent, the through hole 50H is It can not always be said that it is circular.

  In another expression including such a case, in the case of the present embodiment, in the adsorption electrode 30, the size of the cross section of the portion disposed in the through hole 50H of the object 50 is the liquid 50 The separation distance between the adsorption electrode 30 and the inner surface of the object to be coated 50 is set so as not to apply to the inner surface.

  Then, such an adsorption electrode 30 is disposed in the through hole 50H of the article 50, and the article 50 and the adsorption electrode 30 are electrostatically sprayed while the article 50 and the adsorption electrode 30 are maintained at the same potential. Between the liquid spray unit 20 having the nozzle 22 of the apparatus 10, a voltage is applied from the nozzle 22 that generates an electrostatic force that sprays the liquid only by the electrostatic force so that the liquid is sprayed toward the object 50 to be coated. For example, since it is possible to easily apply the liquid to the outer surface of the object 50 while preventing the liquid from being applied to the inner surface of the object 50, the liquid may be applied to the inner surface of the object 50 It is suitable for the case where it is required that almost no liquid is applied.

  In this manner, a liquid is applied to the inner surface of the article 50 having a cylindrical shape having the through hole 50H in the length direction and having a plurality of holes formed in the side wall from the outer surface to the inner surface defining the through hole 50H. The electrostatic spraying method of applying the liquid to the outer surface of the article 50 while not applying the coating is not limited, but in the case of a stent or the like, it may not be desirable to apply the liquid to the inner surface. According to the electrostatic spraying method of the present embodiment, when the substrate 50 is a type of stent that does not want to apply a liquid to the inner surface, the solvent is decomposed and absorbed in the solvent on the outer surface of the reticulated sidewall of the stent. It is particularly suitable for applying a liquid in which the bioresorbable polymer is dissolved.

  The holding portion 45 described in the above embodiment holds the object to be coated 50 and arranges the adsorption electrode 30 in the through hole 50H of the object to be coated 50 so as not to contact the object to be coated 50. This is only one example, and for example, a configuration for holding the object to be coated 50 and a configuration for disposing the adsorption electrode 30 in the through hole 50H of the object to be coated 50 so as not to contact the object 50 to be coated It may be provided separately.

  Further, depending on the method of holding the adsorption electrode 30, there is no problem even if the shape of the adsorption electrode 30 is a rod-like body whose outer diameter does not change in the length direction, and furthermore, the shape of the through hole 50H of the object 50 Accordingly, the cross-sectional shape of the suction electrode 30 may be a polygonal shape such as a rectangular shape.

In addition, the object to be coated 50 is also in a cylindrical shape having a through hole 50H in the length direction, and a plurality of holes penetrating from the outer surface to the inner surface defining the through hole 50H are formed in the side wall. It is not necessary that the cylindrical shape is cylindrical.
That is, the object 50 is a cylindrical body whose outer shape is a polygonal shape such as a rectangular shape, and a plurality of holes penetrating from the outer surface to the inner surface defining the through hole 50H are formed in the side wall thereof. It may be.

Second Embodiment
In the first embodiment, the case where the liquid is not applied to the inner surface of the object to be coated 50 has been described, but in the case of a medical stent or the like, the liquid is applied to the inner surface, It may be required to form a layer of

Here, if the adsorbing electrode 30 is not provided, it is possible to apply the liquid also to the inner surface of the object 50, as described above with reference to FIG. 6 (b).
However, in this case, the amount of liquid to be applied to the inner surface of the object 50 is determined according to the conditions for applying the liquid to the outer surface of the object 50, and the liquid is applied to the inner surface. It is difficult to control the amount (film thickness).

  On the other hand, by using the adsorption electrode 30, it is possible to control the amount of application of the liquid (the thickness of the coating film) to the inner surface of the article 50, and the application of the liquid to the inner surface is appropriate. It can be

  Therefore, in the following, as the second embodiment, the adsorption electrode 30 is used to control the application amount of the liquid to be applied to the inner surface of the object 50, and the liquid is applied to the inner surface of the object 50. The case of application will be described.

  In the second embodiment as well, the configuration of the electrostatic spray device 10 is substantially the same as that of the first embodiment, and therefore, in the following, mainly different points will be described, and the same points as the first embodiment will be described. May be omitted.

In the first embodiment, as described with reference to FIGS. 4 and 5, the first holding body 45ac for holding the object 50 on which the rotary holding portion 45a is provided on the other side of the fitting portion 45ab is used. In the second embodiment, the first holding body 45ac is omitted, and only one end 50a of the object 50 is in contact with the other end 45ab2 of the fitting portion 45ab. It will be in the state.
In addition, the 1st holding body 45ac is abbreviate | omitted, and the specific method of hold | maintaining the to-be-coated-article 50 rotatably is demonstrated later.

  Further, in the first embodiment, the second holding body 47 is provided with the holding end portion 47a, but this holding end portion 47a is also omitted, and the second holding body is in the state of only the stopping portion 47b. The other end 50b of the object 50 is in contact with the stop 47b.

Then, when the second holding body 47 is fitted and fixed to the third rod-like portion 33 of the suction electrode 30, the object 50 is slightly attached to the end 50a on one side to the extent that the object 50 is not deformed. Fix to press in the direction of.
Thus, the object 50 is rotatably held between the fitting portion 45ab and the second holding body 47 together with the fitting portion 45ab.
As described above, since the first holding body 45 ac and the holding end portion 47 a are omitted, the liquid is applied to the inner surfaces of both ends of the object 50 by these as in the first embodiment. There is no inhibition.

  However, as described above, since the holding of the object to be coated 50 is the holding with a force to the extent that the object to be coated 50 is not deformed, as in the first embodiment, When arranged in the horizontal direction, the object 50 may move when it is rotated.

  So, in 2nd Embodiment, the to-be-coated-article 50 is arrange | positioned in the perpendicular direction as arrangement | positioning that the 2nd holding body 47 is located in the perpendicular direction lower side, and the holding part 45 and the support part 43 are located in the perpendicular direction upper side. To be done.

  Then, by making the outer diameter of the third rod-like portion 33 of the adsorption electrode 30 smaller than in the first embodiment, the separation distance between the third rod-like portion 33 of the adsorption electrode 30 and the object 50 is increased. To do.

Although it is illustrated in FIG. 6 (b) that the liquid particle invading the through hole 50H of the article 50 is applied to the inner surface opposite to the side where the liquid particle has infiltrated, the penetration is more detailed. Among the liquid particles that have infiltrated into the holes 50H, the liquid particles having a low penetration speed are attracted to the inner surface of the object 50 present near the intruding point and are applied.
In addition, attracting and coating on the inner surface of the to-be-coated-article 50 which exists in the vicinity of the location which intruded in this way may be described as return adhesion below.

  In the first embodiment, the outer diameter of the third rod-like portion 33 of the adsorption electrode 30 is large, and the surface of the third rod-like portion 33 of the adsorption electrode 30 is near the inner surface of the object 50. Liquid particles having a slow penetration speed are also adsorbed to the adsorption electrode 30, so that no return adhesion occurs and liquid particles are not applied to the inner surface of the article 50.

On the other hand, in the second embodiment, the outer diameter of the third rod-like portion 33 of the adsorption electrode 30 is reduced to the extent that the return adhesion occurs, so that the liquid is also applied to the inner surface of the object 50 to be coated. ing.
Also in the second embodiment, liquid particles having a high penetration speed are adsorbed to the adsorption electrode 30 as in the first embodiment.

Then, depending on how small the outer diameter of the third rod-like portion 33 of the adsorption electrode 30 is, the return adhesion amount of the liquid particles changes.
Therefore, depending on the outer diameter of the third rod-like portion 33 of the adsorption electrode 30, the amount of liquid to be applied to the inner surface of the object to be coated 50 can be controlled.

  And, since the application of the liquid is performed while rotating the substrate 50, the thickness of the coating film formed on the inner surface of the substrate 50 when viewed in the circumferential direction is also made uniform. According to the electrostatic spraying method of the second embodiment, the thickness of the coating film formed on the inner surface is controlled to be a predetermined thickness, and a coating film having a uniform film thickness in the circumferential direction is formed. It is possible.

  As mentioned above, although the electrostatic spraying apparatus 10 of this invention was demonstrated based on specific embodiment, this invention is not limited to said specific embodiment, A deformation | transformation and improvement are given suitably Those included in the technical scope of the present invention are obvious to the person skilled in the art from the description of the claims.

DESCRIPTION OF SYMBOLS 10 Electrostatic spraying apparatus 20 Liquid spraying part 21 Body part 21a Liquid supply port 21b Liquid flow path 21c Hole part 21d Rear end opening part 21e Female screw structure 22 Nozzle 22a Tip outer periphery 22b Opening part 23 Bar 23a Picking part 23b Electrical wiring connection Portion 23c Male thread structure 23d Tip surface 24 Seal member 30 Adsorption electrode 31 First rod portion 31a Position regulating portion 32 Second rod portion 33 Third rod portion 40 Voltage applying means 41 Voltage power source 42 First electric wiring 43 Support portion 43A 1 Body part 43a Reception part 43B First attachment part 43b Screw hole 44 Second electric wiring 45 Holding part 45A Second body part 45a Rotation holding part 45aa Bearing part 45H1 First through hole 45ab Fitting part 45ab1, 45ab2 End face 45ac Holding body 45B second mounting portion 45b screw hole 45H2 second through hole 46 grounding means 47 second holding body 47 Holding end portion 47b retaining portion 47c fourth through hole 50 article to be coated 50a, 50b end portion 50H through hole 60 Terakon

Claims (8)

When a liquid is applied to the outer surface of a substrate having a through hole in the longitudinal direction and a plurality of holes formed in the side wall penetrating from the outer surface to the inner surface defining the through hole, It is an electrostatic spraying method which can also make the application state of the liquid to the inner surface appropriate.
Placing a conductive or semiconductive adsorption electrode of an electrostatic spray device in the through hole of the article;
While the object to be coated and the adsorption electrode are kept at the same potential, the liquid is sprayed only by the electrostatic force from the nozzle between the object to be coated and the adsorption electrode and a liquid spray unit having a nozzle of the electrostatic spray device Applying a voltage to generate the electrostatic force to spray the liquid toward the substrate.   The electrostatic spraying method according to claim 1, wherein the adsorption electrode is disposed in the through hole of the object so as not to contact the inner surface of the object. The coated object is a stent having a reticulated sidewall.
The electrostatic spraying method according to claim 1 or 2, wherein the liquid is a solvent in which a biodegradable and absorbable polymer to be decomposed and absorbed in vivo is dissolved.   The electrostatic spray method according to any one of claims 1 to 3, wherein the adsorption electrode which is a separation distance between the adsorption electrode and the inner surface where the liquid is not applied to the inner surface is used. . When a liquid is applied to the outer surface of a substrate having a through hole in the longitudinal direction and a plurality of holes formed in the side wall penetrating from the outer surface to the inner surface defining the through hole, It is an electrostatic spray device that can properly apply the liquid to the inner surface,
The electrostatic spray device is
A liquid spray unit having a nozzle;
A conductive or semiconductive adsorption electrode disposed in the through hole;
The electrostatic force is generated between the object to be coated and the adsorbing electrode and the liquid spray unit while the liquid is sprayed from the nozzle only by the electrostatic force while keeping the potential of the object to be coated and the adsorbing electrode the same. An electrostatic spray apparatus comprising: voltage applying means for applying a voltage between the object to be coated and the adsorption electrode and the liquid spray section.   The said adsorption | suction electrode is a magnitude | size of the cross section of the part arrange | positioned in the said through-hole of the said to-be-coated-article in the magnitude | size which does not contact the said through-hole of the said to-be-coated-article. Electrostatic sprayer.   The electrostatic spray device according to claim 5 or 6, wherein the adsorption electrode has a length longer than a length of the object to be coated.   The adsorption electrode has a size such that the size of the cross section of the portion disposed in the through hole of the article is the distance between the adsorption electrode and the inner surface for not applying the liquid to the inner surface The electrostatic spray device according to any one of claims 5 to 7, characterized in that