JP2017173044A - Dispensation nozzle and manufacturing method of dispensation nozzle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a dispensation nozzle capable of performing accurate dispensation, by preventing the creeping up of a droplet onto an outer surface (outer wall) of a nozzle tip or remaining or adhesion of a droplet on a nozzle tip surface.SOLUTION: The dispensation nozzle can suck and hold a liquid, and can discharge the sucked and held liquid by a predetermined quantity. At least the nozzle tip of the dispensation nozzle has undergone a water-repellent treatment. The nozzle tip surface is used as a surface roughness providing surface. The water repellency of the surface roughness providing surface having undergone the water-repellent treatment is set higher than that of the outer surface of the nozzle tip that has undergone the water-repellent treatment.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a dispensing nozzle and a method for manufacturing a dispensing nozzle.

  In fields such as biochemistry and chemistry, a dispensing device is used to inspect a specimen (liquid sample). In general, a dispensing apparatus operates a dispensing pump to suck or discharge liquid in a pipe, sucks a liquid sample from a dispensing nozzle connected to the pipe, and sucks the liquid sample. A liquid sample is dispensed at a predetermined position by a predetermined amount.

  That is, the dispensing nozzle 1 dispenses at the step shown in FIG. First, as shown in FIG. 18 (a), the tip 2 of the dispensing nozzle 1 is immersed in the liquid sample S, and the liquid sample S is sucked into the dispensing nozzle 1 and shown in FIG. 18 (b). In this manner, the dispensing nozzle 1 is separated (raised) from the liquid sample S. Next, as shown in FIG. 18 (c), after the droplet 3 is formed, it is spotted on the member 4 to be dispensed as shown in FIG. 18 (d).

  However, as shown in FIG. 18B, when the dispensing nozzle 1 is separated (raised) from the liquid sample S, the liquid sample S adheres to the outer surface 2 a and the tip surface 1 a of the tip 2 of the nozzle 1. Then, as shown in FIG. 18 (c), the liquid droplets creep up to the outer surface 2a of the tip 2 of the dispensing nozzle 1, and the liquid droplet 3 fluctuates. Further, FIG. 18 (d) As shown, when the droplet 3 is dispensed onto the member 4 to be dispensed, residual droplet adhesion occurs on the tip surface 1 a of the dispensing nozzle 1. For this reason, the amount of spotting decreases, which causes a deterioration in dispensing accuracy.

  Therefore, it is important to prevent the liquid sample S from adhering to the outer surface 2a and the tip surface 1a of the dispensing nozzle 1. Therefore, for example, an expert can reduce the adhesion of the liquid sample and improve the dispensing accuracy by discharging the nozzle tip 2 along the wall surface of the container (the container containing the liquid sample S) during dispensing. ing. However, since such a method requires skill and has a large individual difference, the development of a dispensing nozzle that anyone can dispense with high accuracy is desired.

  Conventionally, a pipette tip made of a polypropylene base material coated with a water repellent treatment agent has been proposed (Patent Document 1). In this case, water repellent treatment is applied to the outer and inner surfaces of the liquid storage portion. The water repellent treatment agent is a silicone resin containing at least one specific substance selected from the group consisting of diisononyl phthalate, diisodecyl phthalate, trioctyl trimellitate and poly (1,3-butanediol adipate). The total mass of the specific substance is 1% by mass to 30% by mass with respect to the silicone resin.

  This makes it difficult for the liquid sample to adhere to the surface of the outer wall, thereby effectively suppressing the liquid circulation phenomenon (the liquid sample creeping phenomenon).

  Conventionally, there is a type in which a protrusion that protrudes in the liquid discharge direction is provided on the outer periphery of the discharge end of the discharge channel (Patent Document 2). In this case, since the protrusion that protrudes in the discharge direction of the liquid is provided on the outer periphery of the discharge end of the discharge flow path, when the small amount of liquid held in the measuring portion is discharged by the pressurized gas, The adhesion of liquid can be suppressed.

JP 2009-210562 A JP 2006-226726 A

  In the pipette tip described in Patent Document 1, it is possible to suppress the creeping phenomenon of the liquid sample. However, when this chip is immersed in a liquid, the liquid adheres to the tip portion of the chip, and therefore, due to gravity, it adheres to the droplets collected on the tip surface, and this droplet amount fluctuates. The stable amount of spotting cannot be secured.

  Also in Patent Document 2, the liquid adheres to the protruding portion, and thus adheres to the droplets collected on the tip surface by gravity.

  DISCLOSURE OF THE INVENTION In view of the above problems, the present invention is a dispensing nozzle that can dispense liquid droplets with high accuracy by preventing droplets from creeping up to the outer surface (outer wall) of the nozzle tip and from remaining on the nozzle tip surface. I will provide a.

  The dispensing nozzle of the present invention is a dispensing nozzle capable of sucking and holding a liquid and discharging a predetermined amount of the sucked and held liquid, and having a water-repellent treatment at least at the nozzle tip. The nozzle tip surface is a surface roughness imparting surface, and the water repellency of the surface roughness imparted surface subjected to the water repellent treatment is set higher than the outer surface of the nozzle tip portion subjected to the water repellent treatment. It is what.

  Since the water repellency of the surface roughness imparted surface subjected to the water repellent treatment is higher than the outer surface of the nozzle tip portion subjected to the water repellent treatment, the nozzle tip surface serves as a barrier for liquid movement, It is possible to prevent the droplets from creeping up to the outer surface of the nozzle tip. Further, it is possible to prevent the liquid that wets the outer surface of the nozzle tip from flowing down to the tip. Furthermore, since water repellency is emphasized by imparting surface roughness, the contact of droplets with the nozzle tip surface is suppressed, and the volume of liquid returning to the nozzle side during droplet separation is reduced. Further, the strength of water repellency can be defined in the finely processed region.

  It is preferable that the water repellency of the surface roughness imparted surface subjected to the water repellent treatment is set higher than that of the inner surface of the nozzle tip portion subjected to the water repellent treatment. By setting in this way, it is possible to prevent the liquid from flowing from the inner surface of the nozzle to the tip side.

  The water repellent treatment layer formed by the water repellent treatment is preferably a coating layer using a fluorine-based coating agent. By coating with a fluorine-based coating agent, it is possible to impart high water repellency to metal nozzles and ceramic nozzles that have been given surface roughness by fine processing, leading to improved dispensing accuracy.

  It is preferable that the water contact angle of the surface roughness imparted surface subjected to the water repellent treatment is 120 ° or more. In this way, when the contact angle of water on the surface roughness imparting surface is 120 ° or more, which is difficult to achieve with a smooth surface, contact of liquid droplets with the nozzle tip can be prevented, and dispensing accuracy can be improved. .

  It is preferable that the difference between the water contact angle of the surface roughness imparted surface subjected to the water repellent treatment and the contact angle between the outer surface and the inner surface subjected to the water repellent treatment at the nozzle tip is 10 ° or more. . By setting in this way, it is possible to effectively prevent the droplets from creeping up to the outer surface of the nozzle tip and flowing down to the tip of the liquid that has wetted the outer surface of the nozzle tip.

  The surface roughness of the surface roughness imparting surface is preferably 1.5 times or more due to a plurality of groove structures having a spatial pitch of 100 μm or less. By setting in this way, the groove structure is sufficiently small with respect to the droplets, and water repellency can be exhibited.

  The dispensing nozzle manufacturing method of the present invention is capable of sucking and holding a liquid and discharging a predetermined amount of the sucked and held liquid, and is made of a resin in which water repellent treatment is applied to at least the nozzle tip. A method for producing a dispensing nozzle, wherein the nozzle tip surface is given a surface roughness due to fine processing during mold molding, and the water repellent treatment kneads the additive into the resin before mold molding, This is a resin addition process in which a water repellent component is transferred to the resin surface after mold forming to impart water repellency, whereby the water repellency of the nozzle tip surface subjected to the water repellency treatment is reduced by the water repellency of the nozzle tip. It is set higher than the outer surface and the inner surface where water treatment is performed.

  According to the manufacturing method of the dispensing nozzle of the present invention, the additive is added to the resin before kneading the mold, and after the mold is molded, the water repellent component is transferred to the resin surface to impart water repellency. By doing so, high productivity can be exhibited.

  In the present invention, since the water repellency of the nozzle tip surface is higher than that of the outer surface of the nozzle tip part, droplets creep up to the outer surface (outer wall) of the nozzle tip part and droplet residual adhesion to the nozzle tip surface. This makes it possible to dispense accurately. Furthermore, since water repellency is emphasized by imparting surface roughness, the contact of droplets with the nozzle tip is suppressed, and the volume of liquid returning to the nozzle side during droplet separation is reduced, leading to improved dispensing accuracy. Further, the strength of water repellency can be defined in the finely processed region, and fine positioning of the water repellent treatment region that is difficult to control becomes unnecessary.

It is sectional drawing of the dispensing nozzle which shows embodiment of this invention. It is a principal part expanded sectional view of the dispensing nozzle shown in the said FIG. It is an enlarged view of the front end surface of the dispensing nozzle shown in the said FIG. It is a photograph figure of the surface roughness provision surface of the front end surface of a dispensing nozzle. It is a simplified diagram showing a fluorine coating process. The contact angle of water is shown, (a) is an explanatory view of the contact angle of water on the smooth surface of the water-repellent treatment film, (b) is the contact angle of water on the surface roughness imparting surface of the water-repellent treatment film It is explanatory drawing of. The droplet is supported by the surface roughness imparting surface of the tip surface of the dispensing nozzle, (a) is a simplified sectional view in the Wenzel state state, and (b) is a simplified sectional view in the Cassie-Baxter state state. FIG. The dispensing process is shown, (a) is a simplified diagram of a state in which pure water is sucked, (b) is a simplified diagram of a droplet formation state, and (c) is a simplified diagram of a droplet contact state. (D) is a simplified diagram of a droplet separation state. It is a simplified diagram showing a method for calculating a droplet amount on a substrate. It is a process of sucking 2 μl of water into a dispensing nozzle according to the present invention and dispensing it according to the present invention, (a) is an enlarged view of the nozzle tip in a droplet formation state, (b) It is an enlarged view of the nozzle tip part of the reverse mode which is the state which spotted the droplet. It is the enlarged view which expanded further the reverse mode of the said FIG.10 (b). FIG. 5 is an enlarged view of a full-volume discharge mode in which 0.5 μl is sucked into a dispensing nozzle according to the present invention and droplets are dropped by showing an embodiment. It is an enlarged view just before 0.5 microliters is attracted | sucked to the dispensing nozzle which concerns on this invention, and a droplet is spotted. This is a conventional example, in which 2 μl is sucked into a dispensing nozzle that does not have a surface roughness imparting surface on the tip surface, and is dispensed. (A) is an enlarged view of the nozzle tip in a droplet forming state. (B) is an enlarged view of the nozzle tip in a droplet contact state in which the droplet is brought into contact with the substrate, (c) is an enlarged view of the nozzle tip immediately before the droplet is deposited, d) is an enlarged view of the nozzle tip of the reverse mode in which droplets are spotted. It is the enlarged view which expanded further the reverse mode of the said FIG.14 (d). FIG. 10 is an enlarged view of a full-volume discharge mode in which 0.5 μl is sucked into a dispensing nozzle that does not have a surface roughness imparting surface on the tip surface and drops are dropped by a conventional example. FIG. 7 is an enlarged view immediately before a droplet is deposited by sucking 0.5 μl into a dispensing nozzle according to the present invention, showing a conventional example. The explanation of the conventional problem is shown, (a) is a simplified diagram of the immersed state, (b) is a simplified diagram of the chip wet state, (c) is a simplified diagram of the scooping state, (d) is It is a simplified diagram of a residual adhesion state.

  Hereinafter, embodiments of the present invention will be described with reference to FIGS.

  1 and 2 show a dispensing nozzle 10 according to the present invention. This dispensing nozzle 10 is used in a dispensing apparatus, and is connected to a dispensing pump (not shown) via a pipe or the like. That is, the dispensing apparatus generally sucks or discharges the liquid sample in the pipe by operating the dispensing pump, and sucks the liquid sample from the dispensing nozzle 10 connected to the pipe. The aspirated liquid sample is dispensed by dispensing a predetermined amount to a predetermined position. Examples of the liquid sample include a sample solution such as blood and urine analyzed by a biochemical analyzer, a diluted solution mixed with the sample solution, a mixed solution thereof, water, and various chemicals.

  The dispensing nozzle 10 in the case of this example includes a nozzle body 10a made of a thin pipe and a tip tapered portion 10b provided continuously with the tip of the nozzle body 10a. For this reason, an internal space in which liquid is sucked is provided.

  In this case, the dispensing nozzle 10 is formed by subjecting a resin base material to a water repellent treatment. Examples of the resin base material include polypropylene, polymethyl methacrylate, polystyrene, acrylic resin, polysulfone, polytetrafluoroethylene, polyethylene, vinyl chloride, polyethylene terephthalate, polycarbonate, and other polymers, copolymers, and blend polymers. .

  For the water repellent treatment, for example, a fluorine coating agent or a silicone coating agent can be used. As a coating method, various coating devices such as a general coating device, a spray method, and a dipping method can be used.

  In this case, the tip surface of the dispensing nozzle 10 is a surface roughness imparting surface 12. Here, the surface roughness imparting surface 12 is configured by, for example, a two-dimensional lattice groove as shown in FIGS. 3 and 4. That is, grooves 13 and 13 orthogonal to each other (for example, a groove width of 12 μm, a groove depth of 13 μm, and a groove pitch of 20 μm of each groove 13) are formed. Such groove processing can be performed using a laser surface processing apparatus (not shown).

  The groove shape of the surface roughness imparting surface 12 is not limited to the two-dimensional lattice grooves as shown in FIGS. 3 and 4, and does not have any one of the intersecting grooves 13, 13. Alternatively, the intersecting grooves may not be orthogonal. The surface roughness of the surface roughness imparting surface 12 is preferably 1.5 times or more due to a plurality of groove structures having a space pitch of 100 μm or less.

  Thus, after making the nozzle front end surface into the surface roughness imparting surface 12, for example, as shown in FIG. 5, the surface is immersed in a fluorine-based coating agent produced using a silane coupling agent (adsorbent). The fluorine coating agent S is coated on the roughness applying surface 12 and the outer surface 15 and the inner surface 16 of the nozzle tip 11.

For this reason, at least the surface roughness imparting surface 12 that is the nozzle tip surface and the outer surface 15 and the inner surface 16 of the nozzle tip portion are subjected to water repellency treatment, and a water repellency treatment film (layer) is provided on them. It is formed. By the way, as shown in FIG. 6A, the contact angle of water on the smooth surface F of the water repellent film (fluorine coating agent film) is only about 115 °. As shown in (b), it is necessary to form the surface roughness imparting surface 12. That is, when the surface area magnification is r, the contact angle of the smooth surface is θe, and the apparent contact angle is θw, the relationship between θe and θw is expressed by the following equation (1).

  Further, when the droplet is spotted on the surface roughness imparting surface 12, as shown in FIG. 7 (a), even in the Wenzel state, as shown in FIG. 7 (b), the Cassie-Baxter It may be a state. The Wenzel state is a state in which liquid (water) has entered the recess (groove), and the Cassie-Baxter state is a state in which liquid has not entered the recess (groove). Therefore, the contact angle hysteresis has a large Wenzel state and a small Cassie-Baxter state, and the droplet sliding angle has a large Wenzel state and a small Cassie-Baxter state.

  In this case, the water repellency of the surface roughness imparting surface 12 subjected to the water repellent treatment is set higher than the water repellency of the outer surface 15 and the inner surface 16 of the nozzle tip portion 11 subjected to the water repellent treatment. . That is, the difference between the water contact angle of the surface roughness imparting surface 12 subjected to the water repellent treatment and the contact angle between the outer surface 15 and the inner surface 16 of the nozzle tip 11 subjected to the water repellent treatment is 10 °. The above is preferable. Further, the contact angle of water on the surface roughness imparting surface 12 is preferably 120 ° or more.

  By the way, the surface roughness applying surface 12 is not limited to that provided by forming a groove to be processed using a laser surface processing apparatus (not shown). That is, the surface roughness may be given by fine processing. For this reason, surface roughness may be imparted to the nozzle tip surface by fine processing during mold forming. That is, it is only necessary that a fine uneven portion is formed as the surface roughness imparting surface 12.

  Further, when manufacturing such a resin dispensing nozzle 10, the nozzle tip surface is given a surface roughness by fine processing at the time of mold molding, and the water-repellent treatment is performed by adding an additive before mold molding. It may be a resin addition treatment in which the resin is kneaded into the resin and the water-repellent component is transferred to the resin surface after mold molding to impart water repellency. That is, in this resin addition treatment, for example, a fluorosurfactant is used, and this fluorosurfactant is added to a resin (for example, polypropylene). As described above, when the fluorosurfactant is added, the water- and oil-repellent functions are exhibited by the force of fluorine that has migrated to the surface due to the surface migration of the perfluoroalkyl group.

  In such a water-repellent treatment, a molded product having a water-repellent surface can be obtained simply by kneading the additive into the resin and molding, so compared with the case where the same mechanism is given in the coating treatment. There is an advantage that no immersion and subsequent drying steps are required. In the case of a coating process, a primer process such as a primer process may be required, but this water repellent process does not require such a process.

  High productivity can be achieved by kneading the additive into the resin before mold molding, and after the mold molding, the resin addition process is performed to transfer the water repellent component to the resin surface and impart water repellency. . Moreover, the water repellency of the nozzle tip surface subjected to the water repellent treatment is higher than that of the outer surface 15 and the inner surface 16 of the nozzle tip portion 11 subjected to the water repellent treatment.

  In this way, the nozzle tip surface is given a surface roughness due to fine processing during mold molding, and the water repellent treatment kneads the additive into the resin before mold molding, and the resin surface after mold molding. Even if it is a resin addition treatment in which the water repellent component migrates to impart water repellency, surface roughness is imparted by laser processing and water repellent treatment is formed as described above. The water treatment layer has the same effects as the coating layer using a fluorine-based coating agent.

  If the nozzle 10 configured as described above is used, a sample liquid can be spotted on a stainless steel substrate 20 as shown in FIG.

  Specifically, as shown in FIG. 8A, for example, the tip 11 of the nozzle 10 is immersed in a water tank 22 in which pure water is stored, and in that state, the inside of the nozzle 10 is pumped by a pump (not shown). Then, a predetermined amount (for example, 2 μl) of pure water is sucked into the nozzle 22 to raise the nozzle 10 from the water tank 22. Next, as shown in FIG. 8B, the pure water W in the nozzle 10 is discharged from the discharge port 10 c (see FIGS. 1 and 2) of the nozzle 10, and the tip surface of the nozzle 10, that is, the surface roughness. A droplet 21 is formed on the application surface 12.

  Thereafter, for example, as shown in FIG. 8C, the substrate 20 is raised to approach the droplet. Note that the substrate 20 may be raised, for example, by a predetermined pitch or continuously. When the pitch is increased by a predetermined pitch, for example, the pitch can be set to 10 μm, but is not limited thereto. Moreover, when raising continuously, it can also set arbitrarily as the raising speed.

  By such an increase, as shown in FIG. 8C, the substrate 20 is brought into contact with the droplet. Thereafter, as shown in FIG. 8D, the substrate 20 is lowered. This lowering may also be lowered by a predetermined pitch or continuously. When descending by a predetermined pitch, for example, it can be set to 10 μm, but is not limited thereto. Moreover, when descending continuously, the descending speed can be arbitrarily set.

  In this way, from the state shown in FIG. 8C, if the substrate 20 moves away from the nozzle 10 as shown in FIG. 8D, the droplets adhere to the substrate 20 side, and from the nozzle tip surface. Separate. Thereby, it can be dispensed. In a normal dispensing process, the dispensing nozzle 10 side is moved up and down without moving the substrate 20 side up and down.

  In this dispensing nozzle 10, the water repellency of the surface roughness imparting surface 12 subjected to the water repellency treatment is higher than that of the outer surface 15 of the nozzle tip portion 11 subjected to the water repellency treatment. The surface serves as a barrier for liquid movement, and the liquid droplet 21 can be prevented from creeping up to the outer surface 15 of the nozzle tip 11. In addition, it is possible to prevent the liquid that wets the outer surface 15 of the nozzle tip 11 from flowing down to the tip.

  That is, since the water repellency of the nozzle tip surface is higher than that of the outer surface 15 of the nozzle tip 11, the droplets creep up to the outer surface (outer wall) 15 of the nozzle tip 11 and the droplets remain on the nozzle tip. Adhesion is prevented and dispensing with high accuracy becomes possible. Furthermore, since water repellency is emphasized by imparting surface roughness, the contact of droplets with the tip surface of the nozzle tip portion 11 is suppressed, and the volume of liquid that returns to the nozzle side during droplet separation is reduced, resulting in dispensing accuracy. It leads to improvement. Further, the strength of water repellency can be defined in the finely processed region, and fine positioning of the water repellent treatment region that is difficult to control becomes unnecessary.

  Further, by setting the water contact angle of the surface roughness imparting surface 12 to 120 ° or more, which is difficult to achieve with a smooth surface, contact of liquid droplets with the nozzle tip surface can be prevented and dispensing accuracy can be improved. .

  Further, by setting the surface roughness of the surface roughness imparting surface 12 to be 1.5 times or more by a plurality of groove structures having a space pitch of 100 μm or less, a groove structure that is sufficiently small with respect to the droplets. Thus, water repellency can be exhibited.

  In particular, the difference between the contact angle of water on the surface roughness imparting surface subjected to the water repellent treatment and the contact angle between the outer surface 15 and the inner surface 16 of the nozzle tip 11 subjected to the water repellent treatment is 10 ° or more. By doing so, it is possible to effectively prevent the droplets from creeping up to the outer surface 15 of the nozzle tip portion 11 and the liquid that wets the outer surface 15 of the nozzle tip portion 11 from flowing down to the tip side.

  The present invention is not limited to the above-described embodiment, and various modifications are possible. For example, as the dispensing nozzle 10 of the above-described embodiment, a nozzle body 10a formed of a thin pipe and a tip of the nozzle body 10a The tip tapered portion 10b is connected to the nozzle body, and the tip tapered portion 10b has an axial length shorter than the axial length of the nozzle body 10a. The axial length of the nozzle body 10a may be longer than the axial length of the nozzle body 10a, or the axial length of the tip tapered portion 10b may be the same as the axial length of the nozzle body 10a. Moreover, even if it does not have the front-end | tip taper part 10b, it may not have the nozzle main body 10a which consists of a thin diameter pipe. For this reason, in the said embodiment, although it called the front-end | tip part 11 of the nozzle 10 with the front-end | tip taper part 15b of the nozzle 10, it is not restricted to this, If the axial direction length of the front-end | tip taper part 15b is long, If the tip of the tip taper 15b is the tip 11 of the nozzle 10 and the length of the tip taper 15b in the axial direction is short, the tip taper 15b or one of the nozzle bodies 10a connected to the tip taper 15b is provided. When the tip portion 11 is the tip portion 11 of the nozzle 10, and the tip tapered portion 15b is not provided, the tip portion of the nozzle body 10a may be the tip portion 11 of the nozzle 10.

  The outer diameter and inner diameter of the nozzle tip can be arbitrarily set. That is, the area of the nozzle tip surface can be set arbitrarily. The dispensing nozzle 10 is made of resin in the above embodiment, but the base material is made of a metal such as iron, aluminum or stainless steel, or a ceramic product such as glass or ceramic. It may be coated with a fluorine coating agent or the like. The water-repellent treatment layer formed by the water-repellent treatment is preferably a coating layer using a fluorine-based coating agent. By coating with a fluorine-based coating agent, it is possible to impart high water repellency to metal nozzles and ceramic nozzles that have been given surface roughness by fine processing, leading to improved dispensing accuracy.

  In the embodiment, the water repellency of the surface roughness imparting surface 12 subjected to the water repellency treatment is set higher than the outer surface 15 and the inner surface 16 of the nozzle tip portion 11 subjected to the water repellency treatment. In the present invention, at least the water repellency of the surface roughness imparting surface 12 subjected to the water repellent treatment should be higher than the water repellency of the outer surface 15 of the nozzle tip 11 subjected to the water repellent treatment. . Even such a thing leads to a sufficient improvement in dispensing accuracy. Moreover, as a site | part to which the water-repellent process is performed, the tip part 11 should just be at least, but the whole nozzle may be sufficient. Furthermore, the surface roughness may be imparted to the outer surface 15 and the inner surface 16 of the nozzle tip 11 that have been subjected to the water repellent treatment within a range that does not exceed the surface area magnification than the surface roughness imparted to the nozzle tip.

(Sample creation)
A two-dimensional lattice groove was formed on the tip surface (outer diameter: about 790 μm, inner diameter: about 420 μm) of a polypropylene dispensing nozzle base material. In this case, the tip surface of the dispensing nozzle substrate is surface-roughened by forming grooves having a groove width of 12 μm, a groove depth of 13 μm, and a groove pitch of 20 μm by ultrashort pulse laser processing of the laser surface processing apparatus. The application surface 12 is used. For this reason, when the droplet is supported only on the upper surface of the prism (land portion constituted by grooves formed in a lattice shape), the solid-liquid contact rate Φs is 0.16.

  After processing, fluorine coating was performed by a dip coating method. The coating agent used had a smooth surface contact angle of 114 ° (catalog value) using a silane coupling agent as an adsorbent. As a result, as shown in FIGS. 3 and 4, the tip surface becomes a surface roughness imparting surface 12 that has been subjected to water repellent treatment, and the water repellency is the outer surface of the nozzle tip portion 11 that has been subjected to water repellent treatment. 15 and a sample set higher than the inner surface 16 were prepared.

(Droplet behavior)
2 μl of pure water was discharged from the sample (dispensing nozzle), and droplets were formed on the tip surface of the dispensing nozzle 10. The formation of the droplets 21 is a reverse mode in which a predetermined amount is sucked in advance and discharged when discharged. The SUS304 substrate 20 disposed immediately below the droplet was raised in 10 μm increments until the droplet contacted, and after the droplet contact, it was lowered in 10 μm increments until the droplet separated. FIG. 10A is an image when a droplet is formed, and FIGS. 10B and 11 are images when the SUS304 substrate 20 is spotted.

(Dispensing accuracy)
0.5 μl of pure water was sucked with the sample (dispensing nozzle), and the entire amount was discharged to form droplets 21 on the tip surface of the dispensing nozzle. If the dispensing time is long, there is a concern that the dispensing accuracy will deteriorate due to evaporation, air leakage in the nozzle, etc., so the SUS304 substrate 20 arranged immediately below the droplet is quickly raised in 100 μm increments until the droplet comes into contact with the liquid. After the droplet contact, it was lowered until the droplet 21 was separated. The droplet volume was calculated from the droplet image spotted on the SUS304 substrate 20, and the dispensing accuracy was evaluated.

A method for obtaining the droplet volume will be described with reference to a droplet image showing a spotted state shown in FIG. When the maximum diameter of the droplet on the substrate 20 is 2r, the height of the droplet is H, the contact angle is θ, and the radius of the droplet is R, θ, r, and H The relationship can be expressed by the following equation 2, and the relationship between θ, r, and R can be expressed by the following equation 3.

Therefore, the volume of the droplet shown in FIG. 9 can be expressed by the following equation (4).

  By the way, FIG. 14 shows a droplet behavior when a dispensing nozzle 1 (hereinafter referred to as an unprocessed nozzle) whose tip surface is not subjected to water-repellent treatment and is not a surface roughness imparting surface is used. In this step, the droplet behavior, which is a surface roughness imparting surface having a water repellent treatment at the tip surface, was made the same. That is, FIG. 14A is an image at the time of droplet formation, FIG. 14B is an image in a state where the droplet 3 is in contact with the substrate 4, and FIG. FIG. 14C is an image immediately before separating from the nozzle 1, and FIG.

  When a 2 μl droplet is ejected from the unprocessed nozzle 1, it can be seen that the droplet 3 is in contact with the entire nozzle tip surface. When the SUS304 substrate 4 is raised and the droplet 3 comes into contact, a liquid filament is formed on the nozzle 1 and the substrate 4. When the substrate 4 is lowered in order to spot and separate the droplet 3 toward the substrate, a constriction is formed in the liquid filament, but the state in which the droplet 3 is in contact with the entire nozzle tip surface is maintained until spot separation. After the spotting separation, an increase in the liquid level inside the nozzle (average 212 μm) was observed. The liquid incremental volume inside the nozzle calculated from the nozzle inner diameter was 0.029 μl.

  On the other hand, as shown in FIGS. 10 and 11, in the water-repellent nozzle (nozzle whose tip surface is the surface-roughening surface 12) 10, droplets are discharged from the discharge hole 10c (see FIGS. 1 and 2). It is formed in a hanging state, and it can be seen that contact with the nozzle tip surface is prevented. As soon as the SUS304 substrate 20 was raised and the droplets 21 contacted, the droplets 21 landed on the substrate 20 side. After the spotting separation, an increase in the liquid level inside the nozzle (average 94 μm) was observed, but the liquid incremental volume inside the nozzle was 0.013 μl, which was halved compared to the unprocessed nozzle. Regarding the residual adhesion at the nozzle tip after spotting separation, as shown in FIG. 15, the adhesion volume of the unprocessed nozzle 1 was 0.021 μl. In the water-repellent nozzle 10, as shown in FIG. 11, the adhesion volume was 0.003 μl, which was 1/7 that of the unprocessed nozzle.

(Dispensing accuracy)
A state in which 0.5 μl of pure water is dispensed is shown in FIG. 12 when the water repellent nozzle 10 is used, and in FIG. 16 when the unprocessed nozzle 1 is used. When the raw nozzle 1 is used, a larger amount of residual adhered liquid is generated than when the water repellent nozzle 10 is used, and the droplet size spotted on the substrate 4 (20) is smaller than that of the water repellent nozzle 10. I understand that it is small. As a result of calculating the volume of the droplet on the substrate 4 (20), the water repellent nozzle 10 is effective for improving the dispensing accuracy, which is 0.435 μl when the raw nozzle 1 is used and 0.509 μl when the water repellent nozzle is used. I know that there is.

  In the case of 0.5 μl dispensing where the influence of gravity is small, when the substrate 4 (20) comes into contact with the droplets, a liquid filament is formed between the nozzle and the substrate 4 in the unprocessed nozzle 1 as shown in FIG. Also in the water repellent nozzle 10, a liquid filament was formed between the nozzle and the substrate 20, as shown in FIG. The liquid filament of the water-repellent nozzle 10 is prevented from coming into contact with the nozzle tip surface, and fine constrictions appear in the vicinity of the nozzle. Therefore, the volume of liquid that returns to the nozzle side during droplet separation is reduced, which is thought to have led to improved dispensing accuracy.

10 Dispensing nozzle 11 Nozzle tip 12 Surface roughness imparting surface 15 Outer surface 16 Inner surface

The dispensing nozzle of the present invention is a dispensing nozzle capable of sucking and holding a liquid and discharging a predetermined amount of the sucked and held liquid, and having a water-repellent treatment at least at the nozzle tip. Te water repelling the nozzle tip surface with a surface roughness imparted surface is subjected, as it is set higher than the outer surface repellency of the nozzle tip surface is subjected to water repellent treatment of the nozzle tip is there.

The dispensing nozzle manufacturing method of the present invention is capable of sucking and holding a liquid and discharging a predetermined amount of the sucked and held liquid, and is made of a resin in which water repellent treatment is applied to at least the nozzle tip. A method for producing a dispensing nozzle, wherein the nozzle tip surface is given a surface roughness due to fine processing during mold molding, and the water repellent treatment kneads the additive into the resin before mold molding, This is a resin addition process in which a water repellent component is transferred to the resin surface after mold forming to impart water repellency, whereby the water repellency of the nozzle tip surface subjected to the water repellency treatment is reduced by the water repellency of the nozzle tip. water treatment is shall be set higher than the outer and inner surfaces are subjected.

Claims (7)

A dispensing nozzle capable of sucking and holding liquid and discharging the sucked and held liquid by a predetermined amount, and having a water-repellent treatment at least at the nozzle tip,
The nozzle tip surface is a surface roughness imparting surface, and the water repellency of the surface roughness imparted surface subjected to the water repellent treatment is set higher than the outer surface of the nozzle tip portion subjected to the water repellent treatment. Dispensing nozzle characterized by.   2. The dispensing according to claim 1, wherein the water repellency of the surface roughness imparted surface subjected to the water repellent treatment is set higher than that of the inner surface of the nozzle tip portion subjected to the water repellent treatment. nozzle.   The dispensing nozzle according to claim 1 or 2, wherein the water-repellent treatment layer formed by the water-repellent treatment is a coating layer using a fluorine-based coating agent.   The dispensing nozzle according to any one of claims 1 to 3, wherein a contact angle of water on the surface roughness imparting surface subjected to the water repellent treatment is 120 ° or more.   The surface roughness of the surface roughness imparting surface is 1.5 times or more due to a plurality of groove structures having a space pitch of 100 μm or less. 5. The dispensing nozzle described.   The difference between the contact angle of water on the surface roughness imparting surface subjected to the water repellent treatment and the contact angle between the outer surface and inner surface of the nozzle tip portion subjected to the water repellent treatment is 10 ° or more. The dispensing nozzle according to any one of claims 2 to 5, characterized in that: A method of manufacturing a resin dispensing nozzle capable of sucking and holding a liquid and capable of discharging the sucked and held liquid by a predetermined amount, and having a water-repellent treatment at least on the nozzle tip,
The nozzle tip surface is given surface roughness due to fine processing during mold molding, and the water repellent treatment kneads the additive into the resin before mold molding, and the water repellent component on the resin surface after mold molding. This is a resin addition process in which the water repellency is imparted to the nozzle tip surface subjected to the water repellency treatment, so that the water repellency of the nozzle tip portion is subjected to the water repellency treatment on the outer surface and the inner surface. A method for producing a dispensing nozzle, characterized in that it is set higher than the above.