JP4563560B2 - Internally treated plastic tube manufacturing apparatus and method for manufacturing internally treated plastic tube using the apparatus - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an apparatus for treating an inner surface of a plastic tube with atmospheric pressure glow discharge plasma and a method for producing an inner surface-treated plastic tube using the apparatus.
[0002]
[Prior art]
In recent years, a technique for generating glow discharge plasma under atmospheric pressure has been developed and used in various applications. In this technique, a plasma generating gas such as helium is introduced into a discharge portion formed between a high-voltage electrode and a ground electrode facing each other with a certain interval at atmospheric pressure or near atmospheric pressure, and the electrode Glow discharge plasma is generated in the discharge part by applying a high-voltage AC voltage therebetween.
[0003]
Compared with the conventional plasma treatment under vacuum, the method of surface treatment such as surface modification and thin film formation using atmospheric pressure glow discharge plasma is a device for forming a low-pressure atmosphere and pressure control. Do not need. For this reason, it is used suitably in the field | area which needs to process a large area continuously like a film and a sheet | seat. As a method for securing a plasma generating gas region when performing such a process, a large number of air holes are provided in the electrode, and plasma generating gas is supplied from the air holes, or a material to be processed is introduced and carried out. It has been proposed to surround a processing region with a chamber having a minimum opening and continuously supply a plasma generating gas to the region.
[0004]
However, in such a method, an expensive plasma generating gas such as helium has to be constantly introduced, and the cost is high, so that it is not used for surface treatment of general-purpose plastic films. It is. Therefore, it has been desired to develop an atmospheric pressure glow discharge plasma surface treatment method that is simpler, lower in cost, and has a wide application range.
[0005]
On the other hand, as a continuous processing technique of the inner surface of a plastic tube by atmospheric pressure glow discharge plasma, Japanese Patent Application Laid-Open No. 5-202481 or Japanese Patent Application Laid-Open No. 8-57038 discloses a tube under pressure near atmospheric pressure from one end thereof. Disclosed is a method for performing atmospheric pressure glow discharge plasma processing by applying a high-voltage AC voltage between a high-voltage side electrode and a ground-side electrode while continuously introducing a gas mixture of a gas for generating atmospheric pressure glow discharge plasma and a processing gas. Has been. However, in these methods, when the inner surface treatment of a large-diameter tube is performed, in order to ensure an optimal gas flow rate in order to generate a stable atmospheric pressure glow discharge plasma inside the tube, It is necessary to make the gas flow rate the same at all the positions, and a large amount of plasma generating gas is required, which is very disadvantageous in terms of cost.
[0006]
[Problems to be solved by the invention]
The present invention has been made in order to solve such problems. In treating the inner surface of a plastic tube using atmospheric pressure glow discharge plasma, a large amount of expensive atmospheric pressure glow discharge plasma generation gas such as helium is used. It is an object of the present invention to provide an inner surface-treated plastic tube manufacturing apparatus that does not need to be used. Furthermore, it aims at providing the manufacturing method of the inner surface treatment plastic tube using the apparatus.
[0007]
[Means for Solving the Problems]
The present inventors conducted extensive research. As a result, when processing the inner surface of the tube using atmospheric pressure glow discharge plasma, the region where the atmospheric pressure glow discharge plasma is actually generated is only a relatively narrow region along the inner surface of the plastic tube. It was found that if the gas for generating the atmospheric pressure glow discharge plasma is supplied at an optimum gas flow rate, the process can be performed stably, and the flow rate of the gas for generating the atmospheric pressure glow discharge plasma in other regions does not need to be controlled. Next, the present inventors have found that the above problem can be solved by disposing a blocking means for blocking the gas flow in the region except the glow discharge plasma generation region in the plastic tube. That is, the present invention
[1] · Extruder (A) provided with an annular die,
A take-up means (B) for taking out the plastic tube extruded from the annular die and cooled and solidified at a predetermined speed;
・ High voltage side electrode (C),
・ Ground side electrode (D),
A high frequency power source (E) for applying a high voltage AC voltage between the high voltage side electrode (C) and the ground side electrode (D),
A gas supply line (F) for supplying an atmospheric pressure glow discharge plasma generating gas or a mixed gas of the gas and a processing gas into a plastic tube extruded from an annular die and cooled and solidified during operation;
In operation, an atmospheric pressure glow discharge plasma is generated in a plastic tube by applying a high-voltage AC voltage from a high-frequency power source (E) between the high-voltage side electrode (C) and the ground-side electrode (D) during operation. Can be generated, and
-A shut-off means (G), which is located in the plastic tube during operation and substantially shuts off the gas flow in the region excluding the glow discharge plasma generation region,
An inner surface-treated plastic tube manufacturing apparatus is provided.
[0008]
[2]-During operation, a gas discharge line (H) for discharging gas supplied through the gas supply line (F) into the plastic tube extruded from the annular die and cooled and solidified.
The apparatus for producing an internally treated plastic tube according to [1] is further provided.
[0009]
[3] The gas outlet of the gas supply line (F) and the gas inlet of the gas discharge line (H) are arranged so as to be separated by a glow discharge plasma generation region generated in the tube during operation. It provides the inner surface-treated plastic tube manufacturing apparatus according to [2].
[0010]
[4] The plastic tube manufacturing apparatus according to any one of [1] to [3], wherein the take-up means (B) is a nip roll.
[0011]
[5] Using the plastic tube manufacturing apparatus according to any one of [1] to [4], an atmospheric pressure glow discharge plasma generating gas or a mixture of the gas and a processing gas is injected into a plastic tube extruded from an annular die. Gas is supplied, an AC power source is applied between the high-voltage side electrode (C) and the ground-side electrode (D) by the high-frequency power source (E), atmospheric pressure glow discharge plasma is generated in the plastic tube, and the inner surface of the plastic tube is The present invention provides a method for producing an internally treated plastic tube characterized by being treated.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
The atmospheric pressure glow discharge plasma treatment in the present invention (hereinafter, the atmospheric pressure glow discharge plasma treatment may be simply referred to as plasma treatment, and the atmospheric pressure glow discharge plasma may be simply referred to as plasma) is only an atmospheric pressure glow discharge plasma generating gas. Physical and chemical modification of the surface by the plasma generated by the plasma, physical and chemical modification of the surface by the plasma generated by adding a small amount of processing gas according to the purpose to the plasma generation gas This means plasma treatment, and thin film formation on the surface such as plasma CVD and plasma graft polymerization, and is not limited to one. Also, surface chemical modification such as grafting with reactive monomers based on chemically active species such as radicals and ions generated on the tube inner surface by the plasma treatment of the present invention is performed as a post-process of plasma treatment. It is also possible to do. The term “atmospheric pressure” as used in the present invention does not refer to atmospheric pressure in a strict sense, but the pressure and solution within the range of common sense reached by the inside of a plastic tube that is extruded from an annular die and cooled and solidified. It should be. Further, hereinafter, the atmospheric pressure glow discharge plasma generating gas may be simply referred to as a plasma generating gas, and the mixed gas of the atmospheric pressure glow discharge plasma generating gas and the processing gas may be simply referred to as a mixed gas.
[0013]
The inner surface-treated plastic tube manufacturing apparatus of the present invention includes an extruder (A) having a normal annular die, a take-up means (B) for taking out a plastic tube extruded from the annular die and cooled and solidified at a predetermined speed, and a high pressure. A side electrode (C), a ground side electrode (D), a high frequency power source (E), a gas supply line (F), and a cutoff means (G), and preferably a gas discharge line (H). .
[0014]
Among these, as the extruder (A), those used in normal inflation film forming and pipe forming can be used without limitation.
[0015]
The take-up means (B) means an apparatus capable of continuously moving the formed tube, for example, a nip roll or belt having a drive means usually used in inflation film forming. A conveyor, a drive roll, etc. are mentioned.
[0016]
In addition, the high-voltage side electrode (C) and the ground-side electrode (D) are paired. By applying a high-voltage AC voltage from the high-frequency power source (D) between both electrodes, Plasma can be generated. Normally, the high-voltage side electrode (C) and the ground-side electrode (D) are arranged so that one of them is arranged inside the plastic tube and the other is arranged outside the plastic tube during operation. These are usually arranged so as to have a cylindrical shape and concentrically face each other.
Further, as disclosed in Japanese Patent Application Laid-Open No. 8-57038, a cylindrical rim body made of an insulator such as plastic or ceramic is mounted with a ground side electrode 13 and a high voltage side electrode 23 in a double spiral shape. Even if it is arranged on the outer periphery or inside of the plastic tube, plasma can be generated in the plastic tube, and plasma processing of the inner surface of the tube by the plasma is possible.
[0017]
The material of the high-voltage side electrode (C) and the ground-side electrode (D) is not particularly limited as long as it is a conductive material. In the case of a metal, alloys such as stainless steel, brass, carbon steel, super steel, copper, aluminum These may be used alone or in combination. Alternatively, a non-conductive plastic, ceramic or the like coated with copper, gold or the like and subjected to a conductive treatment can also be used.
[0018]
It is desirable that at least one of the opposing surfaces of the high voltage side electrode (C) and the ground side electrode (D) is covered with a solid dielectric. Examples of the material of the solid dielectric include glass, ceramics, heat resistant plastics and the like. Further, as a covering form of the electrode surface, it is also preferable to form a metal oxide film by oxidizing the metal surface of the electrode.
[0019]
Next, the high frequency power source (E) is used to generate a plasma in the plastic tube during operation by applying a high voltage AC voltage between the high voltage side electrode (C) and the ground side electrode (D). The frequency of the high-voltage AC voltage to be generated is not particularly limited, but is preferably 0.5 kHz to 100 MHz. Further, a pulsed voltage may be applied as the high-voltage AC voltage, or a DC voltage may be superimposed on the high-voltage AC voltage. As an example, a 13.56 MHz one that is often used industrially can be used. Plasma is generated by applying a voltage to the electrodes, but the appropriate electric field strength varies depending on the material, shape, size, etc. of the ground side electrode and high voltage side electrode used. Can be selected as appropriate. If the electric field strength is too low, plasma cannot be generated. Conversely, if the electric field strength is too high, the plasma shifts to arc discharge.
[0020]
The gas supply line (F) means a gas flow path for supplying a plasma generating gas or a mixed gas necessary for generating plasma in the plastic tube. The gas supply line (F) can also be provided in this open portion when the structure of the inner surface-treated plastic tube manufacturing apparatus is such that the most downstream side of the manufactured plastic tube is open. However, the most advantageous structure is that the gas supply line (F) passes through the annular die and appears in a region surrounded by the die slip of the annular die. This structure is similar to a blow-up air supply line provided in an annular die usually used in inflation molding. In the case of supplying the mixed gas through the gas supply line (F), if the processing gas in the mixed gas is sensitive to heat, heat insulation or cooling means is provided in the gas supply line (F). It may be.
[0021]
Next, the blocking means (G) will be described. The shut-off means (G) is provided in order to substantially shut off the gas flow in the region excluding the plasma generation region located in the plastic tube during operation. By blocking the gas flow in the region excluding the plasma generation region by the blocking means (G), most of the gas supplied into the plastic tube passes through the plasma generation region. The gas flow required to achieve the optimum gas flow rate can be greatly reduced.
[0022]
Moreover, it is preferable that the inner surface treatment plastic manufacturing apparatus of this invention is equipped with the gas discharge line (H). The gas discharge line (H) discharges the plasma generating gas or mixed gas supplied from the gas supply line (F) to the plastic tube from the plastic tube. By providing the gas discharge line (H), it becomes easy to control the flow rate of the plasma generating gas or mixed gas passing through the plasma generating region during operation. Further, when the inner surface treatment plastic manufacturing apparatus has a structure in which the plastic tube is closed by a nip roll or the like during operation and the plasma treatment is performed in the closed space, the plastic tube size is slightly reduced. It is convenient for adjustment, and the exhausted plasma generating gas or mixed gas can be recirculated.
[0023]
The gas discharge line (H) can also be provided in this open portion when the structure of the inner surface-treated plastic tube manufacturing apparatus is such that the most downstream side of the manufactured plastic tube is open. However, as described in the gas supply line (F), the most advantageous structure is that it passes through the annular die and appears in a region surrounded by the die slip of the annular die.
[0024]
Further, it is desirable that the gas outlet of the gas supply line (F) and the gas inlet of the gas discharge line (H) are arranged so as to be isolated by a plasma generation region generated in the tube during operation. As described above, since the gas outlet of the gas supply line (F) and the gas inlet of the gas discharge line (H) are arranged, the plasma generating gas or mixed gas supplied to the gas supply line is smoothly plasma. Since it passes through the generation region and the distribution of gas flow velocity in the circumferential direction of the plastic tube inner surface can be made uniform, it is necessary for plasma generation required to achieve the optimum gas flow rate in the plasma generation region. The flow rate of gas or mixed gas can be further reduced.
[0025]
Moreover, it is desirable that the take-up means (B) of the plastic tube manufacturing apparatus is a nip roll. When the take-up means (B) is a nip roll, the plastic tube is closed by the nip roll during operation, and the plasma treatment is performed in this closed space, and the plasma generating gas or mixed gas is opened to the open system. Can be lost. This is particularly effective when the internally treated plastic tube to be manufactured is thin.
[0026]
Hereinafter, the inner surface-treated plastic tube manufacturing apparatus of the present invention will be described more specifically with reference to the drawings. FIG. 1 is a schematic view showing an embodiment of a plastic tube manufacturing apparatus having an inner surface processing function of the present invention. FIG. 2 is a perspective view of the ground side electrode used in FIG. 1 (in FIG. 1, the diameter of the plastic tube is emphasized more greatly to facilitate understanding).
In this embodiment, the inner surface-treated plastic tube manufacturing apparatus is basically a normal pipe manufacturing apparatus including an extruder 4 equipped with an annular die 5, a tube cooler, a tube winder as a take-up means, and the like. . The apparatus is provided with gas supply lines (plasma generating gas introduction line 72 and processing gas introduction line 71) that pass through the inside of the annular die and appear in the region surrounded by the die lip of the annular die. With this structure, plasma generating gas or mixed gas can be supplied into the plastic tube during operation. In the case where the surface treatment is simply performed without performing the surface treatment with the processing gas, it is not necessary to provide the processing gas introduction line 71 among the gas supply lines.
[0027]
Further, the plastic tube manufacturing apparatus of the present invention is equipped with a grounded side electrode 2 for generating glow discharge plasma and a high voltage side electrode 3 connected to a high frequency power source 10. A high-voltage AC voltage can be applied between the ground-side electrode 2 and the high-voltage side electrode 3. In addition, although the example which distribute | arranges the ground side electrode 2 in a plastic tube was shown in this figure, you may make it arrange | position the high voltage | pressure side electrode 3 in a plastic tube (same also in the form mentioned later).
[0028]
As shown in FIG. 2, a blocking means is provided for the ground-side electrode 2 that is to be disposed in the plastic tube during operation. In this example, a disk-like member (blocking plate) is attached to one opening of the ground-side electrode having a cylindrical shape, and the gas flow can be largely blocked except for the glow discharge plasma generation region during operation.
[0029]
FIG. 3 is a schematic view showing another embodiment of the plastic tube manufacturing apparatus having the inner surface processing function of the present invention. 4 is a schematic cross-sectional view taken along the line AA ′ of FIG.
In this embodiment, the inner surface-treated plastic tube manufacturing apparatus is a normal inflation-type tube forming comprising an extruder 4, an air ring 9, a stabilizer plate 62, a nip roll 61, a take-up roll 63, and the like equipped with an annular die 5. The device is the basis. This apparatus is equipped with a gas supply line (plasma generating gas introduction line 72, processing gas introduction line 71) that passes through the inside of the annular die and is surrounded by the die lip of the annular die, and a gas discharge line 73. Has been. With such a structure, during operation, gas can be supplied into the plastic tube, and the gas concentration and pressure in the plastic tube can be maintained at predetermined values by appropriately discharging these gases. . It is also convenient for fine adjustment of the plastic tube size. Further, in this example, the gas outlet of the gas supply line and the gas inlet of the gas discharge line are arranged so as to be isolated by the plasma generation region generated in the tube. In addition, when performing the surface treatment with the plasma generated in the plastic tube without performing the surface treatment with the treatment gas, it is not necessary to provide the treatment gas introduction line 71 among the gas supply lines, and the gas discharge line 73 is installed. It can be omitted. The plastic tube manufacturing apparatus of the present invention is equipped with a grounded ground electrode 2 for generating plasma and a high voltage electrode 3 connected to a high frequency power source 10. A high-voltage AC voltage can be applied between the ground-side electrode 2 and the high-voltage side electrode 3. Here, the ground side electrode 2, the high voltage side electrode 10, the die slip of the annular die, and the plastic tube formed during operation are in a concentric positional relationship. As is clear from FIG. 4, the ground side electrode has a substantially cylindrical shape, and the electrode itself is provided with a blocking means. The flow can be largely blocked.
[0030]
On the other hand, as shown in Japanese Patent Application Laid-Open No. 8-57038, a cylindrical edge made of an insulator such as plastic or ceramic is mounted with a ground side electrode and a high voltage side electrode in a double spiral or comb shape. The present invention can also be applied to a configuration in which the is disposed on the outer periphery of the plastic tube during operation. That is, as the blocking means corresponding to this form, for example, a structure of a device in which a substantially columnar member or a cylindrical member closed on one side is positioned inside the plastic tube can be exemplified.
[0031]
As described above, the exemplary embodiment of the inner surface-treated plastic tube manufacturing apparatus of the present invention has been described by way of example, but these are merely examples and are not limiting. Accordingly, modifications of these examples by those skilled in the art are considered to be included as part of the present invention so long as they are within the spirit and scope of the present invention.
[0032]
Next, an inner surface-treated plastic tube manufacturing method using the inner surface-treated plastic tube manufacturing apparatus of the present invention described above will be described.
In the method for producing an internally treated plastic tube of the present invention, an atmospheric pressure glow discharge plasma generating gas or a mixed gas of the gas and a processing gas is supplied into a plastic tube extruded from an annular die, and a high-frequency power source (E) is used to supply a high-pressure side. An AC power source is applied between the electrode (C) and the ground side electrode (D), and atmospheric pressure glow discharge plasma is generated in the plastic tube to treat the inner surface of the plastic tube. The details will be described below.
[0033]
The glow discharge plasma generating gas used in the present invention is a gas for generating plasma, and is preferably a rare gas or a nitrogen gas. Among the rare gases, helium is most preferable, and argon can also be suitably used.
[0034]
On the other hand, the processing gas added to the plasma generating gas in order to improve the processing effect is appropriately selected according to the purpose of the surface treatment. For example, in order to impart water repellency to a sheet-like material, fluorinated ethylene series hydrocarbon compounds such as tetrafluoroethylene and hexafluoropropylene, and fluorinated methane series carbonization such as tetrafluoromethane and hexafluoroethane. An organic compound having a functional group such as a hydrogen compound, a chain hydrocarbon having a side chain containing a fluorine atom, or a fluorinated aromatic hydrocarbon can be used.
[0035]
In addition, by using the following oxygen element-containing compound and nitrogen element-containing compound as the processing gas, the surface energy is increased by forming hydrophilic functional groups such as carbonyl groups, hydroxyl groups, amino groups on the substrate surface, A hydrophilic surface can be obtained.
[0036]
Examples of the oxygen element-containing compound include oxygen, ozone, water (water vapor), carbon monoxide, carbon dioxide, nitrogen monoxide, nitrogen dioxide, alcohols such as methanol and ethanol, ketones such as acetone and methyl ethyl ketone, and methanol. And organic compounds containing oxygen elements such as aldehydes such as ethanal. A mixture of the oxygen element-containing compound and hydrogen may be used. Further, the oxygen element-containing compound may be mixed with a hydrocarbon compound gas such as methane or ethane. Moreover, hydrophilization is accelerated | stimulated by adding a fluorine element containing compound at 50 volume% or less to the said oxygen element containing compound. What is necessary is just to use the same thing as the said illustration as a fluorine element containing compound.
[0037]
Examples of the nitrogen element-containing compound include nitrogen and ammonia. Examples of the sulfur element-containing compound include sulfur dioxide and sulfur trioxide. Moreover, sulfuric acid can be vaporized and used.
[0038]
In addition, a hydrophilic polymer film can be deposited by using a monomer having a hydrophilic group and a polymerizable unsaturated bond in the molecule as a processing gas. Examples of the hydrophilic group include hydrophilic groups such as a hydroxyl group, a sulfonic acid group, a sulfonate group, a primary or secondary or tertiary amino group, an amide group, a quaternary ammonium base, a carboxylic acid group, and a carboxylic acid group. Can be mentioned. Similarly, a hydrophilic polymer film can be deposited using a monomer having a polyethylene glycol chain.
[0039]
Examples of the monomer include acrylic acid, methacrylic acid, acrylamide, methacrylamide, N, N-dimethylacrylamide, sodium acrylate, sodium methacrylate, potassium acrylate, potassium methacrylate, sodium styrenesulfonate, allyl alcohol, allylamine, polyethylene. Examples include glycol dimethacrylic acid ester and polyethylene glycol diacrylic acid ester.
[0040]
Among the hydrophilic monomers, solid ones used as they are or dissolved in a solvent are vaporized by means such as reduced pressure.
[0041]
In addition, a metal-containing gas can be suitably used as the processing gas. Examples of the metal include Al, As, Bi, B, Ca, Cd, Cr, Co, Cu, Ga, Ge, Au, In, Ir, Hf, Fe, Pb, Li, Na, Mg, Mn, Hg, Metals such as Mo, Ni, P, Pt, Po, Rh, Sb, Se, Si, Sn, Ta, Te, Ti, V, W, Y, Zn, Zr, etc. are mentioned, and the gas containing the metal is used. , Gas for treatment such as metal organic compound, metal-halogen compound, metal-hydrogen compound, metal alkoxide.
[0042]
Specifically, the case where the metal is Si will be described as an example. Tetramethylsilane [Si (CH _Three ) _Four ], Dimethylsilane [Si (CH _Three ) ₂ H ₂ ], Tetraethylsilane [Si (C ₂ H _Five ) _Four ] Organometallic compounds such as silicon tetrafluoride (SiF) _Four ) Silicon tetrachloride (SiCl) _Four ) Silicon dichloride (SiH) ₂ Cl ₂ ) Metal halide compounds; monosilane (SiH _Four ), Disilane (SiH _Three SiH _Three ), Trisilane (SiH _Three SiH ₂ SiH _Three Metal hydride compounds such as); tetramethoxysilane [Si (OCH _Three ) _Four ], Tetraethoxysilane [Si (OC ₂ H _Five ) _Four And the like.
[0043]
If the metal-containing gas is a gas, it can be introduced into the discharge space as it is, but if it is liquid or solid, it may be introduced into the discharge space via a vaporizer. By using such a processing gas, SiO ₂ TiO ₂ , SnO ₂ It is possible to form a metal oxide thin film such as ZnO and to give an electrical and optical function to the surface of the substrate.
[0044]
In addition, the compound used as an above-mentioned process gas may be used independently, and may use 2 or more types together depending on the objective. Further, the mixing ratio when the processing gas and the plasma generating gas (rare gas) are mixed and used is appropriately determined depending on the kind of the plasma generating gas and the processing gas to be used, but the concentration of the processing gas is 10 volumes. If it exceeds 50%, it is difficult to generate a uniform discharge plasma even when a high-voltage AC voltage is applied, so 0.01 to 10% by volume is preferable, and 0.01 to 5% by volume is more preferable.
[0045]
The material of the tube that can be treated in the present invention is not particularly limited as long as it can be extruded. For example, polyolefin resins such as polyethylene (PE) and polypropylene (PP), ethylene-vinyl alcohol Copolymer, ethylene-vinyl acetate copolymer, ethylene-tetrafluoroethylene copolymer, polyethylene terephthalate, polyurethane, polyamide, polyvinyl chloride, polyvinylidene chloride, polyvinylidene fluoride, polycarbonate, polyacetal, polyester, silicone resin, acrylic Resin, polyacrylic acid, polyacrylamide, polymethyl methacrylate, polyvinyl acetate, polyvinyl alcohol, polyacrylonitrile, polystyrene, polysulfone, polyethylene oxide, polyether agent Ketone, polyether sulfone, and the like, but not limited thereto.
[0046]
Next, the manufacturing method of the inner surface treatment plastic tube of this invention is demonstrated in detail, referring FIG. The outline of the apparatus shown in FIGS. 1 and 3 is as described above.
First, in FIG. 1, after starting the continuous production of tubes in a normal tube (pipe) production process, a plasma generating gas such as helium is introduced into the tube using the plasma generating gas introduction line 72. Thereafter, a plasma generating gas or a mixed gas of the gas and the processing gas is continuously introduced from the plasma generating gas introduction line 72, and a high-voltage AC voltage is applied to the high-voltage side electrode 3 from the high-frequency power source 10 to perform glow discharge plasma. Regions are formed and processed.
[0047]
The outer diameter of the ground side electrode 2 is set slightly smaller than the inner diameter of the plastic tube 8 to be manufactured. If the distance between the ground electrode and the plastic tube is too large, stable glow discharge cannot be obtained. The distance between the internal electrode and the plastic tube is preferably 10 mm or less, more preferably 5 mm or less.
[0048]
Next, the manufacturing method of the inner surface treatment plastic tube of this invention is demonstrated, referring FIG.
First, after starting continuous production of tubes in a normal tube production process, the inside of the tube is made into a plasma generating gas such as helium while maintaining the tube internal pressure by using the gas generating line 72 and the exhaust line 73 for generating the plasma. Replace. Thereafter, the plasma generation gas or the mixed gas of the gas and the processing gas is continuously supplied from the plasma generation gas introduction line 72 while discharging the gas in the tube from the exhaust line 73 so as to maintain the pressure in the tube. Then, a high-voltage AC voltage is applied to the high-voltage side electrode 2 from the high-frequency power source 10 to form a plasma region for processing.
[0049]
The outer diameter of an electrode (ground side electrode in this example) arranged inside the plastic tube is set slightly smaller than the inner diameter of the plastic tube 8 to be manufactured. If the distance between the electrode and the tube is too large, stable plasma is hardly generated. The distance between the electrode and the tube is preferably 10 mm or less.
[0050]
The high-voltage side electrode 3 has a cylindrical shape, is attached to a frame or the like of a plastic tube manufacturing apparatus by a high-voltage side electrode support 32 in an insulated state, and is connected to the high-frequency power source 10. Here, the cylindrical high-voltage side electrode 3 is disposed concentrically with the die lip of the annular die 5 or the ground electrode 2, and the inner diameter is set slightly larger than the outer diameter of the plastic tube 8 to be manufactured. The high-voltage side electrode 3 can be divided and used in consideration of workability at the start of tube manufacture.
[0051]
The ground electrode 2 and the high-voltage side electrode 3 are opposed to a line downstream of the so-called frost line, in which the tube 8 is cooled and solidified during operation, via the tube 8 in the state of being coaxial. It is desirable to arrange in this way.
[0052]
The distance between the ground electrode 2 and the high-voltage side electrode 3 is not particularly limited as long as it is equal to or greater than the thickness of the tube, but if it is too narrow, the tube contacts each electrode and obstructs take-up, causes arc discharge, and is too wide. And does not lead to discharge. In this sense, the distance between the ground electrode 2 and the high-voltage side electrode 3 is preferably 0.5 mm to 20 mm.
[0053]
As in the method provided by the present invention, almost all of the plasma generating gas or mixed gas is supplied to the plasma region by providing a blocking means for blocking the gas flow except for the plasma generating region. For this reason, compared with the case where the conventional method is used, the supply_amount | feed_rate of gas required in order to obtain the stable discharge can be suppressed remarkably.
[0054]
【Example】
Hereinafter, the present invention will be described in more detail with reference to examples.
[0055]
[Example 1]
A continuous production apparatus for an internally treated plastic tube as schematically shown in FIG. 3 was produced. As an inflation tube manufacturing apparatus that is the basis of the manufacturing apparatus, a lab plast mill 50MR single screw extruder (20 mm diameter, L / D25 full flight screw) manufactured by Toyo Seiki Co., Ltd. was used. An annular die having a die lip diameter of 25 mm provided with a gas introduction line and an exhaust line, and an air ring were attached thereto, and equipped with auxiliary equipment such as a stabilizer, a nip roll, and a winder. The distance from the upper surface of the die to the nip roll was about 700 mm. The ground electrode having an outer diameter of 44 mm and a height of 50 mm and having an aluminum cylindrical shape is attached to the die lip of the annular die so that the lower end thereof is located approximately 300 mm from the upper surface of the die and is concentric with the die slip. It was attached by a support attached to the enclosed area. Further, as shown in FIG. 3, a high-voltage side electrode having an aluminum cylindrical shape having an inner diameter of 48 mm, a thickness of 4 mm, and a height of 50 mm divided into two parts was installed at a position concentrically facing the internal electrode in the tube. In addition, the high-voltage side electrode divided into two parts has a structure that can be retracted in a sliding manner to improve workability at the start of manufacturing.
Furthermore, a high frequency AC power source capable of applying a 13.56 MHz high frequency AC voltage was connected to the high voltage side electrode. Further, the annular die is provided with a gas supply line and a gas discharge line so that these appear in a region surrounded by the die slip. The position of the gas outlet of the gas supply line is below the ground side electrode, and the gas inlet of the gas discharge line is above the ground side electrode. Thus, the inner surface-treated plastic tube manufacturing apparatus of the present invention was manufactured.
[0056]
Using the above-described apparatus, continuous production of a tube having a tube outer diameter of 46 mm and a thickness of about 100 μm was started using Sumitomo Chemical Co., Ltd. low-density polyethylene F208-0 as a raw material at a nip roll take-up speed of 1.5 m / min. Next, by operating the gas introduction line and the exhaust line, the inside of the tube was replaced with helium while maintaining the gas pressure in the tube and the outer diameter of the tube. Further, in this state, by operating the gas introduction line and the exhaust line, 5 mL / min of oxygen gas was continuously introduced in addition to 1 L / min of helium. Next, the high-voltage side electrode divided into two and retracted in a sliding manner was returned to its original position, and placed at a position concentrically facing the ground electrode in the tube. At this time, the distance between the tube, the ground electrode, and the high-voltage side electrode was about 1 mm. Next, when a high voltage AC voltage of 13.56 MHz was applied from the high frequency AC power source to the high voltage side electrode, plasma was generated between the tube and the ground electrode. In this way, an inner surface-treated polyethylene tube was obtained. The contact angle of water on the inner surface of the polyethylene tube before the treatment was 98.5 °, whereas that on the inner surface of the polyethylene tube after the treatment was 70.6 °, and the treatment effect was clearly recognized.
[0057]
[Comparative Example 1]
The same test as in the example was performed except that a cylindrical internal electrode as shown in FIGS. 5 and 6 was used. At this time, in order to generate stable plasma, it was necessary to set the gas supply rate to 5 L / min.
[0058]
【The invention's effect】
As described above, according to the present invention, when processing the inner surface of a plastic tube using atmospheric pressure glow discharge plasma, it is not necessary to use a large amount of expensive plasma generating gas such as helium. A manufacturing apparatus is provided. Furthermore, the manufacturing method of the inner surface treatment plastic tube using the same apparatus is provided. The inner surface-treated plastic tube that can be manufactured by the inner surface-treated plastic tube manufacturing apparatus and the inner surface-treated plastic tube manufacturing method of the present invention is more advantageous in cost than the conventional one, and is usefully used in each application. .
[Brief description of the drawings]
FIG. 1 is a schematic view showing an embodiment of an inner surface-treated plastic tube manufacturing apparatus according to the present invention.
FIG. 2 is a perspective view of a ground electrode used in FIG.
FIG. 3 is a schematic view showing another embodiment of the inner surface-treated plastic tube manufacturing apparatus of the present invention.
4 is a schematic cross-sectional view taken along line AA ′ in FIG. 3;
FIG. 5 is a schematic view showing a form of an inner surface-treated plastic tube manufacturing apparatus used in a comparative example.
6 is a schematic cross-sectional view taken along the line BB ′ of FIG.
[Explanation of symbols]
1. Internal treatment plastic tube manufacturing equipment
2. Ground electrode
22. Ground electrode support
3. High voltage side electrode
32. High voltage side electrode support
4). Extruder
5). Annular die
61. Nip roll
62. Stabilizer
63. Winding roll
71. Process gas introduction line
72. Gas introduction line for plasma generation
73. Exhaust line
8). Tube (object to be processed)
9. Air ring
10. High frequency power supply

Claims (5)

An extruder (A) equipped with an annular die,
A take-up means (B) for taking out the plastic tube extruded from the annular die and cooled and solidified at a predetermined speed;
・ High voltage side electrode (C),
A ground-side electrode (D) installed within the plastic tube and having a distance of 10 mm or less from the plastic tube whose outer diameter is manufactured ;
A high frequency power source (E) for applying a high voltage AC voltage between the high voltage side electrode (C) and the ground side electrode (D),
A gas supply line (F) for supplying an atmospheric pressure glow discharge plasma generating gas or a mixed gas of the gas and a processing gas into a plastic tube extruded from an annular die and cooled and solidified during operation. An apparatus for generating atmospheric pressure glow discharge plasma in a plastic tube by applying a high-voltage AC voltage from a high-frequency power source (E) between a high-voltage side electrode (C) and a ground-side electrode (D) during operation. In addition,
· An inner surface-treated plastic tube manufacturing apparatus, comprising: a shut-off means (G) that is located in the plastic tube during operation and substantially shuts off a gas flow in a region excluding the glow discharge plasma generation region. . A gas discharge line (H) for discharging the gas supplied through the gas supply line (F) into the plastic tube extruded from the annular die and cooled and solidified during operation is further provided. 2. The inner surface-treated plastic tube manufacturing apparatus according to 1. The gas outlet of the gas supply line (F) and the gas inlet of the gas discharge line (H) are arranged so as to be isolated by a glow discharge plasma generation region generated in the tube during operation. Item 3. The inner surface-treated plastic tube manufacturing apparatus according to Item 2. The plastic tube manufacturing apparatus according to any one of claims 1 to 3, wherein the take-up means (B) is a nip roll. Using the plastic tube manufacturing apparatus according to any one of claims 1 to 4, an atmospheric pressure glow discharge plasma generating gas or a mixed gas of the gas and a processing gas is supplied into a plastic tube extruded from an annular die, Applying a high-voltage AC voltage between the high-voltage side electrode (C) and the ground-side electrode (D) by the high-frequency power source (E), generating atmospheric pressure glow discharge plasma in the plastic tube, and treating the inner surface of the plastic tube A method for producing an internally treated plastic tube.

Images