JPH06117970A - Structure of liquid supply pipe - Google Patents

Abstract

PURPOSE:To obtain a supply pipe which can supply a liquid fully to the end and can drop an accurate amount of liquid by covering the inner surface of the tip part of the pipe with a film obtained by performing dispersion and eutectic reaction of a particle with improved repellency into a metal matrix. CONSTITUTION:The supply pipe A is constituted of a cylindrical needleshaped body part 1 and a film 2 which is covered over the internal total surface and is fitted to the cylindrical metering part of a micro syringe and is used to drop a liquid into a desired container and another liquid. The body part 1 is constituted of a metal material such as stainless steel constituting a general needle. The film 2 consists of fluororesin particle which is subjected to fluoric treatment into a metal matrix or a repellent complex plating where graphite fluoride particle is subjected to dispersion and eutectic reaction. With the complex plating, the fluororesin particle which is subjected to fluoric treatment into a metal plating bath which becomes a matrix is obtained by dispersing a repellent non-metal particle such as graphite fluoride using a proper surface-active agent and then dipping the body part 1 into a dispersion liquid and then performing electrolytic deposition.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure of a liquid supply pipe which is suitable for dropping a small amount of liquid and is excellent in drainage.

[0002]

2. Description of the Related Art A microsyringe is known as an instrument used for dropping a small amount of liquid. This microsyringe is configured by mounting a cylindrical needle-like needle (supply tube) at the tip of a cylindrical measuring unit for measuring liquid,
It is used for dropping a small amount of liquid into a container or a sample in chemical analysis such as gas chromatography.

[0003]

In this type of microsyringe, when the measured liquid is dropped, the entire amount of the liquid must be completely discharged and dropped. Especially, in chemical analysis such as gas chromatography, if the amount of dropping is likely to deviate from the prescribed amount, it may adversely affect the accuracy of analysis. However, since the needle is an extremely thin tube having an outer diameter of about 0.1 to 0.5 mm, which is generally made of a metal material such as stainless steel, liquid easily remains inside the needle, which causes a problem of liquid shortage. there were. In the microsyringe, for example, m
When the liquid of 1 unit or more is dropped, the influence of the error of the residual liquid is small, but when the liquid of a very small amount of μl unit is dropped, it is necessary to completely drop even the liquid droplets attached to the tip of the needle. is there. However, since the droplets attached to the tip of the needle do not fall easily, it is necessary to vibrate the needle to forcefully drop it. There is a problem that it is extremely difficult to drop accurately.

By the way, the present inventor is considering using a film having good water repellency in order to solve the problem of liquid shortage. Here, polytetrafluoroethylene (trade name: Teflon) is prominent as a film having good water repellency, and this is one in which hydrogen in a polyethylene structure is replaced by fluorine, and a hydrogen atom of a hydrocarbon. It is known that the surface energy of the hydrocarbon is significantly reduced by substituting with a fluorine atom. This is because the strong bond energy between C and F and the polarizability of the C and F bond are small, and the CF ₃ group has the lowest surface energy depending on the type of the terminal group of the material. The adhesive force of is reduced and the water repellency is excellent. However, there is a problem that a coating film cannot be formed on the inner surface of the cylindrical thin needle as described above because the resin does not soften and flow even if a water-repellent film is formed using the polytetrafluoroethylene resin. .

The present invention has been made in view of the above circumstances and has a structure in which particles such as a water-repellent resin are dispersed in a metal matrix to form a film by plating, so that a film can be formed even on a needle having a small diameter. It is an object of the present invention to provide a supply pipe in which the liquid can be provided and which is capable of dripping an accurate amount of liquid with good drainage.

[0006]

According to a first aspect of the present invention, in order to solve the above problems, in a structure of a supply pipe in which a liquid passing through the inside is dropped at a tip portion, the supply pipe has a cylindrical main body. Part and a water-repellent film coated on at least the inner surface of the tip part of the body part, wherein the film is a non-metallic particle made of fluorinated fluororesin-based particles or fluorinated graphite particles. It is composed of composite plating that is dispersed and codeposited in a matrix.

In order to solve the above-mentioned problems, the invention according to claim 2 uses the cylindrical main body part according to claim 1 as a needle of a microsyringe.

[0008]

By forming a film in which particles having good water repellency are dispersed and co-deposited in a metal matrix, a film can be formed by plating. Therefore, a film having good water repellency can be formed even on a small-diameter supply pipe such as a needle. As a result, it is possible to obtain a small-diameter supply pipe with good drainage. Needless to say, the supply pipe for forming the film is not limited to the needle of the microsyringe, and may be a pipette, a dispenser, a separating funnel, a general nozzle, or the like. can get.

Embodiments of the present invention will be described below with reference to the drawings. 1 (a) and 1 (b) show an embodiment of a supply pipe (needle) according to the present invention.
Is composed of a cylindrical needle-shaped main body 1 and a film 2 covering the entire inner surface and the entire outer surface of the main body 1, and is attached to the cylindrical measuring portion of a microsyringe to store a liquid in a desired container or liquid. It is used for dripping. The main body 1 is made of a general metal material such as stainless steel that constitutes a general needle.

The coating 2 is made of a water-repellent composite plating in which a fluorocarbon resin particle or a graphite fluoride particle that has been fluorinated is dispersed and co-deposited in a metal matrix. This composite plating is carried out by dispersing fluorinated fluororesin-based particles or water-repellent non-metal particles such as graphite fluoride in a plating bath of a metal serving as a matrix using an appropriate surfactant or the like. It is obtained by immersing the desired main body 1 therein and electrolytically depositing it. The matrix metal used here is Ni, a Ni-based alloy,
Fe, Fe-based alloys, Cu, Zn, Sn, and alloys thereof, etc. are selected in consideration of their adhesion to the metal forming the main body 1, corrosion resistance in the environment of use, and corrosion resistance to the liquid used. Can be used.

As the water-repellent non-metal particles dispersed and precipitated in the matrix metal, fluorinated fluororesin-based particles or fluorinated graphite particles are preferably used, and the particle size is several μm (for example, 4 μm). It is of a degree. In addition, in the present invention, these water-repellent non-metal particles are fluorine-based resin particles, or a carbon material such as fluorinated graphite particles is directly reacted with fluorine, and the outer surface thereof has a highly fluorinated fluorine density. It has a high surface condition. Graphite fluoride {(CF) n}
Is obtained by a direct reaction between a carbon material and fluorine. Fluorine atoms form carbon atoms between graphite layers and SP ³
It is a white covalent intercalation compound that forms a hybrid orbit. (CF) n has a large C—F bonding force, and since a large number of> CF ₂ and —CF ₃ are present on the end faces, the F density on the surface is extremely high due to the structure, and therefore the water repellency is high. Excellent in.

The volume ratio of the water-repellent non-metal particles to the matrix metal is not particularly limited, but if the volume ratio of the water-repellent particles is too large, the water repellency is improved, but the main body 1 If the volume ratio is too small, on the other hand, the adhesiveness to the substrate and the trauma are excellent, but the water repellency is reduced, so the volume occupied by the water-repellent non-metal particles is usually small. Is preferably in the range of 5 to 50%.

Further, in order to improve the adhesion between the main body 1 and the film 2, it is preferable to form fine irregularities on the film forming portion of the main body 1 to roughen the surface. As a means for roughening the surface, if the inner diameter of the main body 1 is small, a chemical method of dipping it in an aqueous solution of an etching agent such as hydrofluoric acid, ammonium fluoride or hydrochloric acid may be used. When the inner diameter of the main body 1 is large, mechanical methods such as shot blasting, sand blasting, liquid honing treatment, and polishing treatment with steel wire, steel wool, etc. can also be applied. The roughness of the fine irregularities is preferably in the range of 0.5 to 5 μm in average roughness, and further, the main body 1 having such a roughened surface is formed.
When the coating film 2 is provided on the substrate, the final surface roughness is preferably about 0.7 to 3 μm in average roughness.

By forming a film 2 for dispersing and eutectifying these resin particles having good water repellency in a metal matrix in the main body 1, even the main body 1 having a small inner diameter of about 0.1 to 0.5 mm. A film can be formed by plating. Therefore, the coating 2 having good water repellency can be formed on the supply pipe A having a small diameter such as a needle. As a result, it is possible to obtain the supply pipe A having a small diameter with good drainage.

By the way, the coating 2 makes the surface of the supply pipe A more water repellent than the surface of polytetrafluoroethylene simple substance which is excellent in water repellency. The reason why such excellent properties are obtained is that the surface of the fluororesin-based particles or the fluorinated graphite particles that are dispersed and deposited has a highly fluorinated surface state with a small amount of surface energy and contains many CF ₃ groups. Body 1 with roughened particles
Since it is dispersed and present on the surface of the composite plating formed at the surface with an appropriate density, it has the effect of reducing the contact area due to roughening, which makes it difficult for water drops to adhere, so to speak, super water repellent. This is because the surface state of

Next, the contact angle of the liquid means the angle indicated by θ when the droplet 4 is placed on the solid surface 3 as shown in FIG. This contact angle can be seen as a measure of wettability. In terms of this contact angle, the contact angle of the Ni-plated single layer is 64 degrees, but by dispersing 3% by weight of (CF) n in the Ni matrix, the contact angle of the coating surface is improved to 130 degrees or more. .

Next, an example of a method of forming the film 2 will be described. FIG. 4 shows an example of the film forming apparatus.
In the apparatus of this example, 5 is a warm bath containing hot water 6,
7 is a plating bath containing the plating solution 8, 9 and 10 are anode plates, 11 is a power supply, and 12 is a current controller. The plating solution 8 used here is a watt bath “NiSO _{4
· 6H 2 O: 280g / l} , NiCl 2 · 6H 2 O: 45
_{g / l, H 3 BO 3} : 40g / l ", sulfamic acid bath" _{Ni (NH 2 SO 3) 2} · 4H 2 O: 350g, NiCl
_{2 · 6H 2 O: 45g /} l, H 3 BO 3: 40g / l "or the like can be used. Further, as the surfactant, a cationic surfactant (10 g / l) (perfluoroalkyl trimethyl ammonium salt, graphite fluoride 1
40 mg / g is necessary) or the like can be used.

The supply pipe A to be composite-plated is immersed in the plating solution 8 of the apparatus shown in FIG. 4, the cathode of the power source is connected to this, and the anode plates 9 and 10 are connected to the anode to energize each. Therefore, electric field deposition may be performed. At this time, the plating solution temperature is about 40 to 50 ° C, and the current density is 0.5 to 20 A · dm.
It can be set to an appropriate value around ^-2 . By this treatment, the coating 2 in which the non-metal particles are dispersed in the matrix metal can be formed on the inner surface and the outer surface of the cylindrical needle-shaped main body 1. If the diameter of the supply pipe A is small,
The plating solution may be circulated inside the supply pipe A so that the composite plating is well deposited on the inner surface side.

(Test Example) Ni was used as the metal matrix, and polytetrafluoroethylene particles were used as the fluorine-based resin particles, and composite plating was performed using the apparatus shown in FIG. For the composite plating, the outer diameter is 0.5 mm,
It is a cylindrical needle having an inner diameter of 0.16 mm and a length of 55 mm and having the shape shown in FIG. The bath composition and treatment conditions of the composite plating are as follows. Bath composition nickel sulfamate 23%, nickel chloride 3%, boric acid 3%, PTFE 5%, pH 4.1 bath temperature 45 ° C, current density 5A / dm ² , treatment time 1479 seconds, film thickness 10-13 μm ,

An experiment in which distilled water was dropped on the obtained needle and the dropping yield was measured is shown in FIG. The dropping yield is {(dropping amount / liquid absorption amount) × 10
It is a value calculated as 0}%. The number of samples during the test was 10. As is clear from FIG. 5, it was revealed that the sample of the product of the present invention having the film formed was superior to the sample having no film in the liquid drainage property. In particular, in the sample of the present invention, the smaller the liquid absorption amount, the better the drop yield, and 0.2 μl produced a large difference from the sample of the conventional product.

By the way, in the above-described examples, the example in which the needle of the microsyringe is used as the liquid supply pipe has been described, but the present invention is applied to a pipette, a dispenser, a separating funnel, a general nozzle, etc. as the liquid supply pipe. Of course, it may be applied. Further, when the supply pipe is made of a non-conductive material, a conductive film can be formed on the portion where the composite plating film 2 is desired to be formed, and it can be formed by utilizing this.

[0021]

EFFECTS OF THE INVENTION By forming a film having a structure in which fluororesin-based particles or graphite fluoride particles having good water repellency are dispersed and co-deposited in a metal matrix on the main body, water repellency becomes excellent, Sharpness is improved. In addition, a film in which the above particles are dispersed in a metal matrix enables film formation by composite plating. Therefore, a film having good water repellency can be formed even on a small-diameter supply pipe such as a needle. As a result, it is possible to obtain a small-diameter supply pipe with good drainage. Needless to say, the supply pipe for forming the film is not limited to the needle of the microsyringe, and the pipette,
It may be a dispenser, a separatory funnel, a general nozzle, or the like, and by applying to these, a supply pipe with good drainage can be obtained.

[Brief description of drawings]

1 (a) is a perspective view of an embodiment of a needle according to the present invention, and FIG. 1 (b) is an enlarged view of the needle of FIG. 1 (a).

FIG. 2 is a perspective view showing a state in which liquid is being dropped by the needle shown in FIG.

FIG. 3 is an explanatory diagram showing a contact angle of a liquid on a solid surface.

FIG. 4 is a configuration diagram showing an example of a composite plating apparatus.

FIG. 5 is a diagram showing test results of a needle according to the present invention.

[Explanation of symbols]

 1 needle, 2 film, 5 hot bath, 6 hot bath, 7 plating bath, 8 plating bath, 9, 10 anode plate, 11 power supply,

Claims (2)

[Claims] 1. A structure of a supply pipe in which a liquid passing through the interior is dropped at a tip portion thereof, wherein the supply pipe has a tubular main body portion, and a water-repellent film coated on at least the inner surface of the front end portion of the main body portion. A liquid supply, characterized in that the coating comprises composite plating in which non-metal particles consisting of fluorinated fluororesin-based particles or fluorinated graphite particles are dispersed and co-deposited in a metal matrix. Tube structure. 2. The structure of a liquid supply pipe, wherein the cylindrical main body according to claim 1 is a needle of a microsyringe.