JP3393444B2 - Atmospheric pressure glow discharge plasma treatment method - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an atmospheric pressure glow discharge plasma processing method, and more particularly, to a large-sized continuous object such as small parts, irregular small parts, powders and small textile products. The present invention relates to an atmospheric pressure glow discharge plasma treatment method for an object that is difficult to perform atmospheric pressure glow plasma treatment.

[0002]

2. Description of the Related Art Conventionally, a method of putting a rare gas such as argon in a high vacuum and treating the surface of an object to be processed by glow discharge has been put into practical use and applied to a high value-added industry such as the electronics industry. There is. However, since this processing method requires a high vacuum, it is not used in general industry in terms of equipment cost and work efficiency.

The present inventor first conducted a plasma discharge by glow discharge in a mixed gas of argon, helium and / ketone under atmospheric pressure to carry out glow discharge, whereby the surface of a plastic or fiber was removed. It has been found that continuous processing can be performed (see Japanese Patent Application Laid-Open No. 4-74525). However, the objects to be treated in these treatment methods are limited to those that can be wound up such as films or sheets, and small parts having a three-dimensional surface, such as rubber oil seal rings, car wiper rubber, and metal rings. There is a problem that it is difficult to continuously treat such things as those such as, or those that are commercialized like clothes instead of fiber, or coarse powder, and that it is difficult to replace air and rare gas. .

[0004]

The present inventor has completed the present invention as a result of various investigations for solving the above problems, and an object of the present invention is to provide a component having a small object to be processed,
It is intended to provide an atmospheric pressure glow discharge plasma treatment method for a substance such as an amorphous small-sized component, powder or small textile product which is difficult to be continuously subjected to the atmospheric pressure glow plasma treatment.

[0005]

SUMMARY OF THE INVENTION The gist of the present invention is to store an object to be treated in a plastic bag in which the internal air is replaced with a rare gas or a mixed gas of a rare gas and a reaction gas, and to exist in the atmosphere. It is positioned between the parallel electrodes, and a high-frequency voltage is applied to the parallel electrodes to generate atmospheric pressure glow discharge plasma inside the bag to impart hydrophilicity or hydrophobicity to the surface of the object to be treated. Atmospheric pressure glow discharge plasma processing method.

That is, in the present invention, the object to be treated is put in a bag made of plastic, the inside of the bag is made into a rare gas or a mixed gas atmosphere of a rare gas and a reaction gas, and the bag is positioned between the electrodes. When a high frequency high voltage is applied to the crimp electrode, the plastic bag itself is a dielectric substance, so that a glow discharge is likely to occur inside the bag, and if a glow discharge occurs, the rare gas or reaction gas in the bag becomes a plasma state. The surface treatment of the object to be treated in the bag can be performed.

The present invention will be described in detail. The plastic bag used in the present invention may be a commonly used bag made of commercially available polyethylene, polypropylene or the like, which has various sizes. Although the one used is the same as or smaller than the size of the electrode. As for the material of the bag, if the material is treated for a short time of about several seconds, a material that is weak to heat such as polyethylene can be used, but preferably a heat-resistant plastic, for example, polyester, polypropylene or pover. A bag made of film such as le is good. However, in general, there are many composite films in which polyethylene is laminated inside the bag in order to impart heat-sealing property to the film, but such a composite film can be used without problems. A particularly preferable bag is one in which two composite films having heat-adhesiveness are combined and three sides thereof are heat-sealed, or three sides are heat-sealed and a zipper is provided on the remaining one side, or rarely. For example, a plastic bag with a stopper provided with a gas inlet plug and a gas outlet plug.

The rare gas used in the present invention is, for example, argon gas, a mixed gas of argon gas and helium gas, or hydrogen gas. Further, as the reactive gas, not only a gas at normal temperature but also a liquid at normal temperature and having a vapor pressure will naturally generate a vapor at normal temperature and become a gas state, which causes a radical reaction in plasma. Because it can be used. The type of reactive gas differs depending on whether hydrophilicity is imparted to the object to be treated or hydrophobicity is imparted, but reactive gases that impart hydrophilicity include oxygen, silane compounds, and alcohols (methyl alcohol). , Ethyl alcohol) ketones. Examples of the reactive gas that imparts hydrophobicity include carbon tetrafluoride, methane, ethane and ethylene. In particular, CF ₄ (carbon tetrafluoride) is odorless and can be used comfortably. Degreasing treatment can also be performed as a kind of surface treatment. For example, a lubricant such as stearic acid is often attached to the surface of aluminum, but the lubricant can be evaporated and degreased by plasma energy by the treatment method of the present invention.

All the electrodes are placed in an air atmosphere so that the distance between the electrodes can be adjusted freely. The distance between the electrodes is usually 5 to 150 mm, which is determined by the type of gas and the voltage. The applied voltage and frequency vary depending on the distance between the electrodes and the type of atmospheric gas in the bag, but usually the frequency is 50 Hz to 50 KHz, preferably 500 Hz to 20 KHz, and more preferably 1 K.
Hz to 10 KHz. If it is lower than 50 Hz, the glow output is extremely weak and the treatment efficiency is poor, and it is possible even if it exceeds 50 KHz, but it is difficult to generate heat because a large bag material does not have very good heat resistance. The voltage is not specified, but it is usually 1500 V to 10 kV. For example, when the distance between the electrodes is 10 mm and the gas in the bag is argon and water vapor, a pale purple glow discharge occurs at 5000 Hz and 5000 V.

Further, the size of the electrode can be freely designed because it can be placed in an air atmosphere regardless of the treatment method of the present invention. Since the plastic of the bag is a good dielectric, it is not necessary to put a dielectric on the electrode surface. However, when performing surface treatment of conductive materials such as metal, parts that use a part of metal, clothing that uses metal buttons, carbon products, etc., use a thin plastic film such as a bag. Since dielectric breakdown occurs, the surface of the high voltage applying electrode and the ground electrode must be covered with a dielectric. In this case, a glass plate, a synthetic mica plate or a plastic sheet is usually used as the derivative. This plastic sheet
Also preferable are phenol resin, polyimide polyester, and synthetic rubber, which have high insulation and heat resistance.

The treatment time is from 5 seconds when hydrophilic.
It is 1 minute, preferably 10 to 30 seconds, and the hydrophobization requires a long time because of causing a radical reaction, and is usually about 5 to 20 minutes. However, there are some differences depending on the reaction gas,
It may take a longer time. Particularly in the case of carbon tetrafluoride, it depends on the degree of hydrophobicity, and it takes 30 minutes or more to completely repel water like a polka dot, that is, to make the contact angle close to 180 degrees. There is also.

The object to be treated is not particularly limited in its size, shape or material. Specific examples of the object to be treated are O-rings, handkerchiefs, powders of organic or inorganic compounds, pellets of elastic, small parts, textile products such as clothes and threads, syringes made of plastic or glass, blood collection tubes or There are medical instruments such as tubes.

Next, the present invention will be described with reference to the drawings. Figure 1
2 is an example of an electrode used when carrying out the present invention.
Is a plan view of the bag to be filled with the object to be treated, and FIG. 3 shows another embodiment of the plastic bag for filling the object to be treated. Further, FIG. 4 shows a case in which these bags are filled with an object to be treated and placed between the electrodes. In FIG. 1, an electrode 2 is fixed to a support frame 3 made of an insulator, and an electrode 1 is arranged so as to face the electrode 2 and a support rod 4 penetrating the support frame 3 is adjusted to adjust a gap between the electrodes. adjust. As for the electrodes, as shown in FIG. 1, only the high voltage applying electrode is held in a completely insulated state, and the lower electrode is grounded or has a floating ground.

In FIG. 2, a plastic bag 5 is filled with an object 6 to be treated, air inside is replaced with an inert gas, and an opening is heat-sealed to seal the bag. Figure 3 instead of this plastic bag
As shown in Fig. 4, a plastic bag with a stopper provided with a gas inlet plug 8 and a gas outlet plug 9 is used, and its opening is sealed with a zipper or is not sealed at all times. It may be performed while circulating gas.

A few examples of the processing method of the present invention are as follows. For example, as the plastic bag, a composite of polyvinyl alcohol (poval) and polyethylene is used, and the size is 40 mm × 12 mm. As shown in FIG. 2, 20 nitrite rubber O-rings (outer diameter 20 mm) were placed therein and the mixture was sealed with a heat seal in which the air in the mixture was replaced with a mixed gas of 70 parts of helium and 30 parts of argon. At this time, 12m at the thickest part in the center as shown in Fig. 2.
It was m. When this is put between electrodes as shown in FIG. 4 and the distance between the electrodes is 12 mm and a voltage of 2 KHz and 3500 V is applied, glow discharge occurs inside the bag and purple light is filled. When energized for 10 seconds, taken out and floated on water, all the treated products immediately settled, and the surface wettability was remarkably improved. The untreated O-ring floated in water and showed water repellency. Further, in the same manner, when a mixed gas of 95 parts of helium gas and 5 parts of carbon tetrafluoride is caused to flow into the bag containing the O-ring and a voltage is applied at the same time, an orange glow discharge is generated. When electricity was supplied for a minute and then taken out, the water repellency was further increased and the surface smoothness (sliding) was greatly improved.

A bag was made of a polyimide film having a thickness of 25 μm, a handkerchief was placed therein, and the air therein was replaced with a mixed gas of 90 parts of helium and 10 parts of CF ₄ . After that, sealing was performed so that the thickest part in the center of the bag was 25 mm. 5 KHz with electrode spacing of 25-26 mm, 2
When a voltage of 800 V was applied, the plasma was entirely filled with an orange glow discharge. It was energized for 5 minutes and the handkerchief was taken out. Treated handkerchiefs are remarkably water repellent and the water rolls like balls, while untreated handkerchiefs immediately wet.

Since it takes a long processing time to carry out such hydrophobic treatment, it is better to use a bag made of a film having higher heat resistance such as polyimide or Teflon. It should be noted that such a plasma-processed and hydrophilized product with the amount of gas in the bag only contains an inert gas, so it can be transported and stored to the end of the distribution mechanism without opening it. is there.

Recently, there is a plastic zipper which can be easily sealed in a bag, which is very convenient for carrying out the process of the present invention. In particular, if a bag as shown in FIG. 3 is made, replacement and removal can be performed quickly, which is even better.
Since argon does not cause a glow discharge under atmospheric pressure, it is necessary for the present inventor to already use water vapor as in the case of Japanese Patent Application No. 4-117514 to generate glow, and argon and helium are mixed. Also 1 Argon
If more than 50 parts out of 00 parts, steam is used together. The hydrophilic effect is further improved by using steam in combination.

[0019]

EXAMPLES The present invention will be described in more detail by way of examples, but the present invention is not limited to these examples. Example 1 A bag of 100 mm × 200 mm was made by heat seal using a boblon film manufactured by Nippon Synthetic Chemical Industry. The boblon film is a composite film of poval, polypropylene and polyethylene and is characterized by having almost no oxygen gas permeability. 100 g of titanium oxide powder was placed in this, and the air therein was replaced with argon gas saturated with steam at room temperature, and the mixture was sealed with a heat seal. Next 150m
Two brass plates measuring mx 250mm are used as upper and lower electrodes, and a polyester film having a thickness of 50 microns is attached only to the upper electrode. The size may be exactly the same as the electrode. The thickness of the bag containing 100g of titanium oxide is 12m
It was m. A bag in which the distance between the upper and lower electrodes is 12 mm is sandwiched by the electrodes, and a voltage of 3500 V at 5 KHz is applied to the electrodes.
The inside of the bag glows a pale bluish purple due to glow discharge. The titanium oxide was energized for 30 seconds, taken out, opened, and plasma-treated titanium oxide was put into water and stirred gently. Similarly, untreated titanium oxide was also placed in water for comparison, but the plasma-treated one exhibited extremely good dispersion. Conventionally, when treating a powdery substance, a chalet is used, the powder is put into this, placed in a reaction vessel between the electrodes, air in the vessel is replaced with a rare gas, and further gas is introduced. However, in the method of this embodiment, the amount of gas is sufficient to replace the air in the bag, which is extremely economical.

Example 2 10 m of wool was put in a polyethylene bag having a zipper and plasma-treated in exactly the same manner as in Example 1. The size of the bag is 135 mm × 220 mm, which is commercially available. The gas used was a mixture of 40 parts of argon and 60 parts of helium, and the air in the bag was replaced. Since polyethylene is weak to heat, its frequency is low and a voltage of 1 KHz and 3000 V was applied. It was treated for 40 seconds because purple glow discharge occurred.
After the treatment, when compared with the untreated yarn, the treated yarn is completely wet with water and sinks, but the untreated yarn is not wet at all and remains floating on the water surface.

EXAMPLE 3 A small piece (about 5 cm ² ) of a hard aluminum foil was used as 20 pieces.
The foil was placed in the same boblon bag as in Example 1 and the foil was surface-treated. Since these are electrically conductive, a synthetic mica plate having a thickness of 1 mm was laminated as a derivative on the upper and lower surfaces of the brass electrode, and a bag was placed therebetween. The gas inside is also argon and water vapor as in the first embodiment. The thickness of the bag is about 8 mm at the center. In order not to press the bag, the interval between the upper and lower dielectrics was set to 10 mm, and a voltage of 8 KHz and 2700 V was applied. Since the thick mica plate was stretched, glow discharge with almost no yarn discharge occurred. As a result of treating for 30 seconds and measuring the contact angle of the aluminum surface, the untreated one was 63 degrees, while the treated one was 38 degrees, showing a remarkable improvement in the wettability of the surface.

Example 4 Five glass microscope slides were placed in the same boblon bag as in the example, and the glass surface treatment was performed. The gas is argon helium oxygen, and the ratio is 30 parts argon, 6 helium.
9.5 parts of oxygen and 0.5 part of oxygen were introduced into the bag of the above boblon provided with an inlet and an outlet, and the electrodes were positioned in the upper and lower electrodes without any dielectric. The mixed gas was flowed only in the bag with a meteor of 100 cc / min and was discharged little by little from the outlet to replace the air therein. 5KHz600 as it is
When a voltage of 0 V was applied, the inside of the bag was filled with reddish purple glow discharge, so that electricity was supplied for 1 minute. When the slide glass is taken out after energization, the slide glass is completely degreased, becomes a clean surface, and is completely wet with water. The untreated one was water-repellent in the flat part, but the treated one showed extremely good hydrophilicity as the fingerprint part disappeared.

[0023]

As described above, according to the present invention, the object to be treated is housed in a plastic bag, the atmosphere in the bag is a rare gas, and the rare gas is placed between the electrodes to cause a glow discharge between the electrodes. It is possible to perform plasma treatment on the surface of the object to be treated by an extremely simple operation of generating, and the surface of the object to be treated can be changed to hydrophilic or hydrophobic depending on the kind of the reactive gas in the bag. The effect is great.

[Brief description of drawings]

FIG. 1 is a side view of an example of an electrode used for carrying out the present invention.

FIG. 2 is a plan view of a bag to be filled with an object to be processed.

FIG. 3 is a perspective view of another plastic bag that is filled with an object to be processed.

FIG. 4 is a side view when a bag is filled with an object to be processed and placed between electrodes.

[Explanation of symbols]

1, 2 electrode 5 plastic bag 8
Gas introduction plug 3 Support frame 6 Workpiece 9
Gas discharge plug 4 Support rod 7 Heat seal part 10
Zipper

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ identification code FI // C23C 16/50 C23C 16/50 (58) Fields investigated (Int.Cl. ⁷ , DB name) B01J 19/08 H01L 21 / 205 H01L 21/31 H05H 1/46 D06M 10/02

Claims (6)

(57) [Claims] 1. An object to be treated is housed in a plastic bag in which the internal air is replaced with a rare gas or a mixed gas of a rare gas and a reaction gas, and the objects are placed between parallel electrodes existing in the atmosphere, and parallel to each other. An atmospheric pressure glow discharge plasma treatment method, characterized in that a high frequency voltage is applied to the electrodes to generate atmospheric pressure glow discharge plasma inside the bag to impart hydrophilicity or hydrophobicity to the surface of the object to be treated. 2. The rare gas is helium, argon, or a mixed gas of helium and argon.
The atmospheric pressure glow discharge plasma treatment method according to the item. 3. The reactive gas is a gas or vapor of a fluorine compound typified by CF ₄ , a lower alcohol, an aliphatic hydrocarbon, an aromatic hydrocarbon, a ketone or a silane compound. The atmospheric pressure glow discharge plasma treatment method according to the item. 4. The plastic bag is made of polyethylene, polypropylene, polyester, polyvinyl alcohol.
The atmospheric pressure glow discharge plasma treatment method according to claim 1, which is made of a synthetic resin simple substance such as silicone rubber, synthetic rubber, polyimide, aramid, or Teflon, or a composite material made of the synthetic resin. 5. The high frequency is 50 Hz to 50 KH.
The atmospheric pressure glow discharge plasma processing method according to claim 1, wherein z is z. 6. The atmospheric pressure glow discharge plasma treatment according to claim 1, wherein when the rare gas has an argon ratio of more than 50 parts, water vapor is contained in an amount of 1% or more. Law.