JPH05170954A - Tube and its production - Google Patents

Abstract

PURPOSE:To obtain a tube secured in smooth fluid flow even in the case of its small diameter, differing in surface energy between its inner wall and section by plasma treatment of a tube's inner wall alone. CONSTITUTION:A tube's inner wall alone is put to plasma treatment, and as necessary, the resulting tube is immersed in a monomer-contg. solution to make graft polymerization of the monomer to the inner wall, thus affording the objective tube differing in surface energy between the inner wall and the outer wall or section.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tube used as a fluid passage and a method for manufacturing the tube. In particular, it relates to one having a small cross-sectional area.

[0002]

2. Description of the Related Art Tubes for guiding fluids such as water are
Many are known so far. Focusing on those with a small tube cross-sectional area, for example, those with an inner diameter of 1 mm or less, these are composed of a single material because of the difficulty in manufacturing technology due to the small cross-section. The determinants of the constituent materials were mainly mechanical strength, elasticity, and weather resistance according to the usage environment. In recent years, the material has been vigorously resinified in terms of mass productivity and manufacturing cost.

[0003]

However, in the above-mentioned prior art, there is a lack of consideration regarding the interaction between the inner wall of the tube and the fluid flowing therein, and there are considerable problems especially when the cross-sectional area of the tube is small. Had. Taking the case of a small-diameter resin tube intended to flow water as an example, many resins have an affinity with water, that is, water wettability is poor, so bubbles easily occur in the tube,
Due to this, problems such as being unable to deliver a constant flow rate and stopping the water flow have occurred.

Therefore, in order to solve the above-mentioned conventional problems, the present invention aims to secure a smooth fluid flow even with a small diameter, so that the surface energy of the inner wall thereof depends on the purpose of use. (EN) Provided is a controlled tube and a manufacturing method thereof.

[0005]

In order to solve the above-mentioned problems, the tube of the present invention is characterized in that the outer wall or cross-section and the inner wall have different surface energies. Also,
The tube of the present invention is characterized in that the affinity of the fluid flowing in the tube with the inner wall is better than the affinity of the fluid with the outer wall or the cross section. The tube of the present invention is characterized by being made of resin. Further, the tube of the present invention is characterized in that only the inner wall of the tube is plasma-treated. Further, the tube of the present invention is characterized in that only the inner wall of the tube is subjected to surface graft polymerization treatment.

The tube manufacturing method of the present invention is characterized in that only the inner wall of the tube is plasma-treated.
Further, the tube manufacturing method of the present invention is characterized in that only the inner wall of the tube is plasma-treated by diffusing plasma particles into the tube due to the pressure gradient inside the tube. The gas used for plasma is characterized by containing at least one of air, oxygen, and argon. Further, in the method for producing a tube of the present invention, (a) a step of plasma-treating only the inner wall of the tube, (b) a step of immersing the tube in a solution containing a monomer, and (c) a graft polymerization of the monomer on the inner wall of the tube. And a process. The tube manufacturing method of the present invention includes (a) a step of plasma-treating only the inner wall of the tube, (b) a step of exposing the tube to a gas containing a monomer, and (c) a step of graft-polymerizing the monomer on the inner wall of the tube. It consists of and.

The present invention will be described in detail below with reference to examples.

[0008]

【Example】

(Embodiment 1) First, an outline of the plasma device used in this experiment will be briefly described with reference to the drawings. FIG. 1 shows a plasma generator capable of diffusing plasma particles on the inner wall of the tube. Plasma generation region 1 in chamber 1
2 is provided, and the plasma particles generated here are discharged to the exhaust port 3 via the plasma particle diffusion port 13. Therefore, by connecting the target tube 101 to the plasma particle diffusion port 13, it is possible to perform plasma processing only on the inner wall of the tube 101 by utilizing the pressure gradient with the exhaust port 3. Next, a method of generating plasma in the plasma generating region 12 will be described. A cylindrical electrode 11 is inserted in the center of the plasma generation region 12 via an insulator 4, and a high frequency (13.56 MHz) is supplied from a high frequency power source 5. A desired gas is introduced from the gas inlet 2 while the chamber 1 and the plasma generation region 12 are sufficiently evacuated,
After reaching a fixed state at a predetermined pressure, plasma is generated in the vicinity of the electrode 11 by applying a high frequency. The generated plasma spreads almost uniformly in the plasma generation region 12,
It diffuses into the chamber 1 in a jet form from the plasma particle diffusion port 13. The outline of the plasma device has been described above, and the result of plasma processing of the inner wall of the tube using the present device will be described below.

Inner diameter 1 mm, outer diameter 2 mm, length 300 mm
A Teflon tube was prepared. One end of this tube was connected to the plasma particle diffusion port 13, and exhaust was performed until the pressure in the chamber 1 reached 0.001 torr. Subsequently, oxygen gas (purity 99% or more) was supplied from the gas inlet 2 and the pressure in the plasma generation region 12 was 0.05.
Adjusted to torr. In this state, a high frequency power of 100 watts is applied to the electrode 11 to apply the plasma generation region 12
Oxygen plasma was generated inside, and plasma treatment was performed on the inner wall of the Teflon tube. The treatment was stopped after 60 seconds, and the Teflon tube was recovered from the chamber 1. The inner wall plasma-treated Teflon tube thus obtained was cut into 10 pieces (Samples 1 to 10) having a length of 30 mm, and the following evaluations were performed.

Pure water was poured into a glass petri dish having a diameter of 100 mm to a depth of 3 mm (about 23.56 m).
l). The sample piece prepared previously was dipped to a depth of 2 mm from the tip so that the cross section was parallel to the water surface. 10
After soaking for a second, the sample was pulled up, and the amount of pure water permeated into the tube was evaluated by measuring the permeation distance h (height). For comparison, the same evaluation was performed on untreated Teflon tubes (Comparative Examples 1 to 5). The results are shown in Table 1. As is clear from Table 1, the samples (Samples 1 to 10) obtained according to the present invention all have a penetration distance h of 18 mm or more, and have good affinity with pure water, that is, good water wettability. .. On the other hand, the conventional one (Comparative Examples 1 to 1
For 5), almost no pure water permeated into the tube (permeation distance h was 2 mm or less), and the inner wall of the tube remained a water-repellent surface peculiar to Teflon. From the above, it was found that the inner wall of the Teflon tube was treated with oxygen plasma.

[0011]

[Table 1]

Example 2 A polypropylene tube having an inner diameter of 1 mm, an outer diameter of 2 mm and a length of 300 mm was prepared. One end of this tube was connected to the plasma particle diffusion port 13 of the plasma device shown in FIG. 1 and exhausted until the pressure in the chamber 1 reached 0.001 torr.
Subsequently, air (atmosphere) was supplied from the gas inlet 2 and the pressure in the plasma generation region 12 was adjusted to 0.04 torr. In this state, a high frequency power of 120 watts was applied to the electrode 11 to generate air plasma in the plasma generation region 12 and plasma treatment of the inner wall of the polypropylene tube was performed. After 30 seconds, the treatment was stopped and the polypropylene tube was recovered from the chamber 1. The inner wall plasma-treated polypropylene tube thus obtained was cut into 10 pieces (Samples 1 to 10) having a length of 30 mm, and the following evaluations were performed.

Pure water was poured into a glass petri dish having a diameter of 100 mm to a depth of 3 mm (about 23.56 m).
l). The sample piece prepared previously was dipped to a depth of 2 mm from the tip so that the cross section was parallel to the water surface. 10
After soaking for a second, the sample was pulled up, and the amount of pure water permeated into the tube was evaluated by measuring the permeation distance h (height). For comparison, the same evaluation was performed on untreated polypropylene tubes (Comparative Examples 1 to 5).
The results are shown in Table 2. As is clear from Table 2, the samples (Samples 1 to 10) obtained according to the present invention all have the permeation distance h of 18 mm or more and have good affinity with pure water, that is, good water wettability. .. On the other hand, compared with the conventional ones (Comparative Examples 1 to 5), pure water hardly penetrated into the tube (penetration distance h was 2 mm or less), and the inner wall of the tube remained a water-repellent surface specific to polypropylene. From the above, it was found that the inner wall of the polypropylene tube was treated with air plasma.

[0014]

[Table 2]

Example 3 A silicon tube having an inner diameter of 1 mm, an outer diameter of 2 mm and a length of 500 mm was prepared. The inner wall of this tube was plasma-treated in the same manner as in Example 1. The plasma treatment conditions were the same as in Example 1 except that argon (purity 99% or more) was used as the introduction gas.
After performing inner wall plasma treatment, this was set in a microtube pump (MP-3 type manufactured by Tokyo Rika Kikai) and a liquid delivery test of pure water was performed. The pump flow rate was set to 10.0 ml / min, liquid was fed for 10 minutes, and then pure water flowing out from the tube end was collected every minute, and the volume was measured.
Table 3 shows the change in the flow rate for 10 minutes after the start of recovery. The same evaluation was performed on the untreated silicon tube (Comparative Example 1) together with the sample according to the present invention (Sample 1). As is clear from Table 3, the flow rate of the pure water flowing out through the sample 1 was constant, and it was found that it was faithful to the set value of the pump. During the liquid delivery test, the inside of the tube was observed, but it was found that there was no air bubble inside the tube, which made it possible to deliver the liquid at a stable constant flow rate. On the other hand, in Comparative Example 1, a remarkable change in the flow rate is recognized. When the inside of the tube was observed during the liquid transfer test,
It was found that bubbles were generated everywhere in the tube, which made it difficult to send a liquid at a constant flow rate. From the above, the plasma treatment of the inner wall of the tube improves the water wettability of the inner wall, and the bubble discharge effect of the flow path is imparted,
It became possible to deliver liquid at a constant flow rate more stable than before.

[0016]

[Table 3]

Example 4 A polyurethane tube having an inner diameter of 1 mm, an outer diameter of 2 mm and a length of 300 mm was prepared.
One end of this tube was connected to the plasma particle diffusion port 13 of the plasma device shown in FIG. 1 and exhausted until the pressure in the chamber 1 reached 0.001 torr. Continued argon gas from the gas inlet 2 (purity 99% or more)
And the pressure in the plasma generation region 12 is 0.1 torr.
Adjusted to r. Output 10 to the electrode 11 in this state
A high frequency of 0 watt was applied to generate argon plasma in the plasma generation region 12, and plasma treatment of the inner wall of the polyurethane tube was performed. Stop processing after 30 seconds have passed,
The tube was recovered from chamber 1. Next, this tube was immersed in a 10 wt% acrylamide aqueous solution, deaerated in vacuum, and then left in a constant temperature bath at 60 ° C. for 1 hour. By this operation, polyacrylamide was surface-grafted on only the inner wall of the tube. The inner wall graft-treated polyurethane tube thus obtained was sufficiently washed with pure water to give a length of 3
The pieces were cut into 0 mm pieces and 10 pieces (Samples 1 to 10), and the following evaluations were performed.

Pure water was poured into a glass petri dish having a diameter of 100 mm to a depth of 3 mm (about 23.56 m).
l). The sample piece prepared previously was dipped to a depth of 2 mm from the tip so that the cross section was parallel to the water surface. 10
After soaking for a second, the sample was pulled up, and the amount of pure water permeated into the tube was evaluated by measuring the permeation distance h (height). For comparison, the same evaluation was performed on untreated polyurethane tubes (Comparative Examples 1 to 5). The results are shown in Table 4. As is clear from Table 4, the samples (samples 1 to 10) obtained according to the present invention all have a penetration distance h of 20 mm or more, and have good affinity with pure water, that is, good water wettability. .. On the other hand, the conventional one (Comparative Example 1)
For (5) to (5), almost no pure water permeated into the tube (permeation distance h was 2 mm or less), and the inner wall of the tube remained a water-repellent surface peculiar to polyurethane. From the above, it was found that the inner wall of the polyurethane tube was remarkably improved in water wettability as compared with the conventional case by the surface graft treatment.

[0019]

[Table 4]

Example 5 A polyurethane tube having an inner diameter of 1 mm, an outer diameter of 2 mm and a length of 300 mm was prepared.
One end of this tube was connected to the plasma particle diffusion port 13 of the plasma device shown in FIG. 1 and exhausted until the pressure in the chamber 1 reached 0.001 torr. Oxygen gas (purity 99% or more) was supplied from the gas inlet 2 to adjust the pressure in the plasma generation region 12 to 0.1 torr. In this state, a high frequency power of 100 watts was applied to the electrode 11 to generate oxygen plasma in the plasma generation region 12, and plasma treatment of the inner wall of the polyurethane tube was performed. After the lapse of 30 seconds, the treatment was stopped, and N-vinyldimethylamine gas was continuously supplied from the gas inlet 2 to adjust the pressure in the plasma generation region 12 to 0.05 torr. In this state, a high frequency power of 100 watts was applied to the electrode 11 to generate plasma in the plasma generation region 12, and the inner wall of the polyurethane tube was subjected to gas phase graft polymerization treatment. After 30 seconds, the treatment is stopped and the chamber 1
More tubes were collected. The inner wall graft-treated polyurethane tube thus obtained was sufficiently washed with pure water and then cut into 10 pieces (samples 1 to 10) having a length of 30 mm,
The evaluation shown below was performed.

Pure water was poured into a glass dish having a diameter of 100 mm to a depth of 3 mm (about 23.56 m).
l). The sample piece prepared previously was dipped to a depth of 2 mm from the tip so that the cross section was parallel to the water surface. 10
After soaking for a second, the sample was pulled up, and the amount of pure water permeated into the tube was evaluated by measuring the permeation distance h (height). For comparison, the same evaluation was performed on untreated polyurethane tubes (Comparative Examples 1 to 5). The results are shown in Table 5. As is clear from Table 5, the samples (samples 1 to 10) obtained according to the present invention all have a penetration distance h of 20 mm or more, and have good affinity with pure water, that is, good water wettability. .. On the other hand, the conventional one (Comparative Example 1)
For (5) to (5), almost no pure water permeated into the tube (permeation distance h was 2 mm or less), and the inner wall of the tube remained a water-repellent surface peculiar to polyurethane. From the above, it was found that the inner wall of the polyurethane tube was remarkably improved in water wettability as compared with the conventional case by the surface graft treatment.

[0022]

[Table 5]

Although the present invention has been described in detail based on the embodiments, it has been obtained that the technique of the present invention is applicable regardless of the material, length, inner diameter, etc. of the target tube. Examples of materials include polyethylene, polyvinyl chloride, polyvinylidene chloride, acetate, polyester,
It was applicable to all resins such as polyvinyl alcohol, polystyrene, polycarbonate, acrylic resins.

Furthermore, the fluid flowing in the tube is not limited to water, but any liquid (including highly viscous ones) or one containing liquid as a main component (for example, solvent in which powder is dispersed, blood, etc.) The problem can be solved by optimizing the interaction with the inner wall with respect to a state in which the components are dispersed) or a gas.

[0025]

As described above, according to the present invention, the surface condition of the inner wall of the tube is optimized for the medium in contact with the inner wall of the tube. In the case of a resin tube, it has been possible to solve the problem that air bubbles are easily generated in the tube, which has been conventionally caused, which makes it impossible to deliver a constant flow rate or stops the water flow. Further, in the tube manufacturing method of the present invention, since plasma particles are diffused inside the tube, it is possible to treat the inner wall of the tube having a small diameter, which has been difficult so far, and the industrial contribution is great.

[Brief description of drawings]

FIG. 1 is a schematic view of a plasma generator capable of diffusing plasma particles on an inner wall of a tube.

[Explanation of symbols]

 1 Chamber 2 Gas Inlet 3 Exhaust 4 Insulator 5 High Frequency Power Supply 11 Electrode 12 Plasma Generation Area 13 Plasma Particle Diffusion Port 101 Tube (Sample)

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Yoshiaki Mori 3-3-5 Yamato, Suwa City, Nagano Seiko Epson Corporation

Claims (10)

[Claims] 1. A tube characterized in that the outer wall or cross section of the tube and the inner wall have different surface energies. 2. The tube according to claim 1, wherein the affinity of the fluid flowing in the tube with the inner wall is better than the affinity of the fluid with the outer wall or the cross section. 3. The tube according to claim 1, which is made of resin. 4. The tube according to claim 1, wherein only the inner wall of the tube is plasma-treated. 5. The tube according to claim 1, wherein only the inner wall of the tube is surface-grafted. 6. A method of manufacturing a tube, which comprises subjecting only the inner wall of the tube to plasma treatment. 7. The plasma particles are diffused in the tube by a pressure gradient in the tube.
A method for producing the described tube. 8. The method for producing a tube according to claim 6, wherein plasma of a gas containing at least one of air, oxygen and argon is used. 9. A method comprising: (a) plasma treating only the inner wall of the tube; (b) immersing the tube in a solution containing a monomer; and (c) graft-polymerizing the monomer on the inner wall of the tube. Characteristic tube manufacturing method. 10. A process comprising: (a) plasma-treating only the inner wall of the tube; (b) exposing the tube to a gas containing a monomer; and (c) graft-polymerizing the monomer onto the inner wall of the tube. The method of manufacturing a tube.