JP2001269569A - Discharge treatment apparatus and discharge treatment method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an apparatus and method capable of subjecting an object to be treated not only to discharge treatment at a high speed but also to surface roughening treatment without damaging the same. SOLUTION: A discharge treatment apparatus is equipped with a pair of electrodes 1a, 1b arranged in opposed relationship, a means 3 capable of applying high AC voltage across both electrodes and a means 4 capable of passing gas based on air through the space 15 formed between both electrodes at a speed of 10 m/sec or more. In a discharge treatment method, the object 5 to be treated is arranged between the pair of the electrodes arranged in opposed relationship and high AC voltage is applied across both the electrodes and the gas based on air is passed through the space 15 formed between both the electrodes at a speed of 10 m/sec or more and discharge generated between both electrodes is allowed to act on the object to be treated.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a discharge processing apparatus and a discharge processing method.

[0002]

2. Description of the Related Art In a corona discharge treatment, for example, a discharge is generated by applying an AC high voltage between a pair of electrodes arranged such that a corona discharge electrode is opposed to a roll or flat reference electrode. And a method of processing the object disposed between the pair of electrodes by the discharge. Such corona discharge treatment has the following problems. (1) The object to be processed may be damaged by repeated discharge. For example, there is a case where an object to be processed made of a thermoplastic resin is melted. Such a phenomenon was remarkable when a high frequency AC high voltage was applied. (2) When the AC high voltage is a sine wave, the discharge is liable to be concentrated, so that a pinhole is generated and the object to be processed is easily damaged. Further, in order to industrially utilize the corona discharge treatment, it is necessary to be able to perform a discharge treatment at a high speed. As one method for this purpose, it is considered to increase the discharge energy density per unit area of the electrode. However, as described above, even under normal conditions, there is a possibility of damaging the object to be processed, such as melting the object or generating pinholes. It has been extremely difficult to carry out corona discharge treatment under conditions where discharge energy density is high, which is a condition that is likely to occur. Furthermore, it is known that the surface of the object to be treated can be roughened by corona discharge treatment, but no technology that can be used industrially has been known.

[0003]

The inventors of the present invention have conducted intensive studies to solve the above-mentioned problems, and as a result, the gas formed in the space formed between the electrodes at a speed of 10 m / sec or more. By passing through, not only the temperature of the object to be processed and the ambient temperature can be lowered, but also the discharge can be made uniform (reduction of discharge concentration), and even if the discharge energy density is increased, the object to be processed is damaged. It has been found that discharge processing can be performed stably at high speed without any trouble, and that the surface can be roughened by increasing the discharge energy density. Further, they have also found that the discharge portion can be downsized because the discharge energy density can be increased. The present invention is based on such knowledge, and provides a discharge treatment apparatus and a discharge treatment method that can perform a discharge treatment at a high speed and can also perform a roughening treatment without damaging an object to be treated. With the goal.

[0004]

SUMMARY OF THE INVENTION Accordingly, the present invention provides a pair of electrodes arranged opposite to each other, means for applying an AC high voltage between the two electrodes, and a device formed between the two electrodes. In a space that is open, a gas mainly composed of air
/ Sec, and a means capable of passing therethrough at a speed of / sec or more. In a preferred aspect of the electric discharge treatment apparatus of the present invention, there is provided means capable of applying an AC high voltage having a pulse waveform between the two electrodes. In another preferred aspect of the electric discharge treatment device of the present invention, a gas mainly composed of air is supplied into the space formed between the two electrodes at a velocity of 85 m / s.
There is provided a means that allows the passage of ec or more.

Further, according to the present invention, an AC high voltage is applied between the electrodes in a state where the object to be processed is disposed between a pair of electrodes arranged opposite to each other, and the electrodes are formed between the electrodes. A gas mainly composed of air is introduced into the space at a speed of 10 m / sec.
The present invention also relates to a discharge processing method, characterized in that a discharge generated between the two electrodes is caused to act on the object to be processed by passing through the electrodes at c or more. In a preferred aspect of the discharge treatment method of the present invention, an AC high voltage having a pulse waveform is applied between the two electrodes. In another preferred embodiment of the discharge treatment method of the present invention, a gas mainly composed of air is passed through the space formed between the electrodes at a speed of 85 m / sec or more.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION The discharge treatment apparatus of the present invention is described below.
This will be described with reference to FIGS. 1 to 3 which are schematic cross-sectional views of the discharge treatment apparatus. Discharge treatment apparatus 10 of the present invention in the embodiment shown in FIG.
, The flat electrode 1a carrying the dielectric layer 2a
And a plate-like electrode 1b carrying a dielectric layer 2b are arranged so as to face each other at a predetermined interval, and a processing target is formed in a processing space 15 formed between these dielectric layers 2a and 2b. The body 5 can be arranged. The object 5 to be processed
Can be arranged in any state as long as it does not hinder the passage of the gas in the processing space 15. For example, as shown in FIG. Either the body layers 2a and 2b are arranged in a non-contact state with each other, or the body layers 2a and 2b are arranged so as to be in contact with the entire surface of the other dielectric layer 2a, or a part of the object 5 is treated with the dielectric layers 2a and / or Alternatively, it can be arranged so as to be in contact with the dielectric layer 2b.

One of the flat electrodes 1a is connected to a high-voltage AC power supply 3 via a conducting wire 13 and the other is flat so that an AC high voltage can be applied between the flat electrodes 1a and 1b. The electrode 1b is grounded via a ground wire 12. Further, a gas ejection device 4 is provided which can pass a gas mainly composed of air into a space formed between the electrodes at a speed of 10 m / sec or more. In addition, the gas ejection device 4 may be provided with a ventilation pipe 4a for guiding the gas, as the case may be.

[0008] In the present invention, the electrode (e.g., the planar electrodes 1a, 1b) but the material is not particularly limited constituting a specific resistance 10 ³ Ω · cm or less (preferably 10 ⁰ Omega · cm or less), for example, a metal (for example, stainless steel, aluminum, or tungsten, etc.), a conductive metal oxide, carbon, or a conductive rubber (for example, metal powder or carbon powder, etc.). A composite of a conductor and rubber) can be used. Note that each of the flat electrodes 1a, 1
b from the periphery of their opposing surfaces to the side walls 11a, 11b.
b, each of the flat electrodes 1a, 1a has a curved surface.
Since the electric field is unlikely to be concentrated between the side walls 11a, 11b of b and the respective dielectric layers 2a, 2b, damage to the dielectric layers 2a, 2b can be suppressed.

Each of the dielectric layers 2a and 2b carried on each of the flat electrodes 1a and 1b is made larger than the opposing surface of each of the flat electrodes 1a and 1b. From the opposing surfaces of the electrode electrodes 1a, 1b to the side walls 11a,
When the coating is performed over 11b, it is possible to prevent a spark discharge that easily occurs between the plate-like electrodes 1a and 1b. Further, since the discharge processing can be performed only in a region sandwiched between the two flat electrodes 1a and 1b, the discharge processing can be performed only in a desired region. For example,
When the flat electrode and the grid electrode are used, only the region of the object to be processed existing in the region corresponding to the shape of the grid electrode can be subjected to the discharge treatment, that is, the discharge treatment in a grid shape.

Each of the dielectric layers 2a and 2b is preferably non-porous as a whole, but may partially include a porous portion. If the porous portion is continuous in the thickness direction of the dielectric layer, a spark discharge may occur in the porous portion. It is preferably not continuous from the opposing surface) to the back surface (contact surface with the electrode). Each dielectric layer 2
The material constituting a and 2b is not particularly limited as long as it is an insulating material. For example, glass (for example, quartz glass or the like), ceramic (for example, alumina, zirconia, titania, or strontium titanate), rubber ( For example, a synthetic rubber such as silicone rubber, chloroprene rubber, or butadiene rubber, or a natural rubber, or a thermoplastic resin (eg, polytetrafluoroethylene, polyester, or the like) can be used. Among them, glass and ceramics can be preferably used, and particularly, quartz glass, alumina, or zirconia having excellent high voltage resistance can be preferably used. The thickness of the dielectric layer is not particularly limited because it is affected by the dielectric strength and the relative dielectric constant of the dielectric, but is preferably about 0.05 mm to 200 mm.

Although the electrodes 1a and 1b in FIG. 1 both carry the dielectric layers 2a and 2b, only one of the electrodes can carry the dielectric layer. Alternatively, when the object to be processed is an insulating film, the film itself acts as a dielectric, so that it may not be necessary to carry a dielectric layer on any electrode. When the rising is not steep as in the case where the AC high voltage is a sine wave, it is preferable that both electrodes carry a dielectric layer.

In the present invention, the pair of electrodes are arranged to face each other at a predetermined interval. The predetermined interval can be appropriately changed depending on the thickness of the object to be processed, but the object is brought into contact with one of the electrode surfaces (or the surface of the dielectric layer when a dielectric layer is carried). When the discharge treatment is performed in a state in which the object is treated, the distance between the other surface (non-contact surface) of the object to be treated and the surface of the counter electrode (or the surface of the counter dielectric layer) is preferably 5 mm or less.
mm is more preferable. The lower limit is 5
It is preferably μm. Further, when performing the discharge treatment in a state where the object to be processed is not brought into contact with any electrode surface (or the surface of the dielectric layer), one surface of the object to be processed and the electrode surface (or the surface of the dielectric layer) facing the one object And the interval
The sum of the distance between the other surface of the object to be processed and the surface of the other electrode (or the surface of the dielectric layer) opposite to the surface is preferably 5 mm or less, more preferably 1 mm or less. The lower limit is preferably 5 μm. In this case, the distance between the surface of the object to be processed and the surface of the electrode (or the surface of the dielectric layer) opposed thereto may be the same or different. In FIG. 1, one flat electrode 1a is connected to the AC high-voltage power supply 3, and the other flat electrode 1b is grounded. However, contrary to FIG. 1, the flat electrode 1a is grounded and the other flat electrode 1a is grounded. The flat electrode 1b can be connected to the AC high-voltage power supply 3.

The waveform of the voltage applied between both electrodes is particularly limited.
Not a sine waveform, a pulse waveform,
Or it can be a rectangular waveform or the like. Among these
With a pulse waveform, the discharge can be made more uniform.
Therefore, it is suitable. If this pulse waveform, start up
2 μsec for both set and fall times
(Microsecond) or less, preferably 0.5 μs
c or less, more preferably 0.2 μsec or less.
More preferably, there is. Note that the “rise time”
1 (p in FIGS. 4 and 5).₁) From 10%
1 until reaching 90% of the peak voltage (FIG. 4 or FIG. 4).
Is t in FIG.₁). Also, "fall time"
Is a boosted voltage derived from the first peak voltage (FIG. 4)
And p in FIG. _Two) As a reference voltage, and the reference voltage (FIG. 4)
And p in FIG._Two) And the reverse peak voltage (p in FIGS. 4 and 5)_Three)
Time to reach 10% to 90% of the voltage difference with
(T in FIG. 4 or FIG. 5)_Two).

Such a pulse waveform is obtained, for example, by a method in which a voltage stored in a capacitor is instantaneously connected to a load by a spark discharge switch, a method in which semiconductor switches are connected in series and a high voltage is directly switched, a method in which a semiconductor switch is modulated. The voltage can be generated by a method of boosting the pulsed voltage through a transformer. Further, in order to shorten the rise time and the fall time, for example, a magnetic switch can be used. Further, the polarity of the voltage is not particularly limited, and may be unipolar or bipolar. However, it is preferable that the voltage is bipolar in terms of high processing efficiency.

The required applied voltage varies depending on the distance between the electrodes (the distance including the thickness of the dielectric layer even when a dielectric layer is present) and the atmosphere around the electrodes, and cannot be limited. 2KVp so that discharge easily occurs
It is more preferably at least 5 KVp. On the other hand, the upper limit of the applied voltage is not limited as long as the voltage does not cause damage to the object to be processed, but about 100 KVp is appropriate. The unit “KVp” indicates a voltage difference from the maximum value peak of the applied voltage to 0. Further, the electric field intensity is not limited as long as the dielectric and the object to be processed are not damaged, but is preferably 10 to 500 KVp / cm, more preferably 20 to 300 KVp / cm. The electric field strength refers to a value obtained by dividing the voltage applied to the electrodes by the distance between the electrodes (the distance including the thickness of the dielectric layer even when the dielectric layer is present).

The frequency of the necessary applied voltage is preferably 1 kHz to 500 kHz, more preferably 10 kHz.
z to 200 kHz. If the frequency is less than 1 kHz, the time required for the discharge treatment tends to be long,
If the frequency exceeds 0 KHz, the object to be processed and the dielectric may be destroyed due to overheating due to dielectric heating. Further, the applied power is preferably 2.5 W / cm ² or more, and 5 W / cm ² or more.
cm ² or more is more preferable. It should be noted that the upper limit of the applied power is not particularly limited because it varies depending on the gas flow velocity, flow rate, and the like. This applied power can be obtained, for example, from the applied voltage at the discharge unit and the Lissajous figure of the discharge charge.

Such an AC high voltage can be applied continuously or intermittently. In the case of intermittent application, the number of repetitions per second is preferably within the above frequency range. That is, the number of repetitions per second is preferably from 1,000 to 500,000, and more preferably from 10,000 to 200,000.

FIG. 1 shows an embodiment in which the gas ejection device 4 is provided as a means for passing a gas mainly composed of air at a speed of 10 m / sec or more through the space formed between the electrodes. A gas suction device can be used instead of the gas ejection device 4, and these can be used together. If the speed is less than 10 m / sec, the cooling effect of the object to be processed, the cooling effect of the atmosphere in the discharge processing space, and the uniforming effect of the discharge tend to decrease. A more preferred speed is 85 m / sec or more, and an even more preferred speed is 100 m / sec or more. The upper limit of the gas flow rate is not particularly limited, and may vary as appropriate depending on the structure of the discharge treatment device, applied power, desired degree of discharge treatment, and the like. In particular, when the waveform of the AC high voltage is a sine wave, the velocity at which the gas passes is preferably 85 m / sec or more, and more preferably 100 m / sec or more. Further, when the waveform of the AC high voltage is a pulse wave, it is sufficient if the gas passing speed is 10 m / sec or more. It is preferable that the higher the applied power, the faster the passage speed of the gas, regardless of the waveform of the AC high voltage.

"Velocity of passing gas" in the present invention
Determines the flow rate (m ³ / sec) of the gas that has passed through the space formed between the pair of electrodes at one atmosphere (m ³ / sec) in a cross section orthogonal to the gas passage direction of the space formed between the pair of electrodes. A value (unit = m / sec) divided by the sectional area (m ² ) of the space. If the cross-sectional area of the space formed between the pair of electrodes is not constant, the value obtained by dividing the flow rate by the smallest cross-sectional area of the space is referred to as the “gas passing speed”.

The gas passing through the space formed between the pair of electrodes can be cooled. When the gas is cooled in this way, it is preferable that the gas does not liquefy. For example, when cooling air, it is preferable to cool so as not to generate water droplets, and if it does, it is preferable to remove water.

The gas passing through the space formed between the pair of electrodes is not particularly limited as long as the gas is mainly air. Here, the "gas mainly composed of air" means a gas containing 20% by volume or more (preferably 50% by volume or more) of air in the whole volume, and is preferably air itself. Examples of the gas that can be mixed with air include a gas for stabilizing discharge (for example, a rare gas or nitrogen) or a reactive gas for introducing a functional group.

As the rare gas, for example, helium, neon, argon, krypton, xenon, radon or the like can be used. The reactive gas is not limited as long as it is a gas capable of introducing a desired functional group. For example, an oxygen-containing compound gas, a nitrogen-containing compound gas, a sulfur-containing compound gas, a phosphorus-containing compound gas, or the like may be used alone. Or mixed and used. Further, an organic compound gas such as alcohol or ketone may be mixed with these gases.

In order to impart hydrophilicity to the object to be treated, it is preferable to use an oxygen-containing compound gas and / or a sulfur-containing compound gas. As the oxygen-containing compound gas, for example, oxygen, air, carbon monoxide, or carbon dioxide can be used.As the sulfur-containing compound gas, for example, hydrogen sulfide, sulfur monoxide, sulfur dioxide, sulfur trioxide, Disulfur trioxide, sulfur heptoxide or the like can be used. Although not particularly shown in the discharge treatment apparatus in FIG. 1, means (for example, a pair of rolls) capable of carrying in and carrying out the object to be treated between a pair of electrodes.
Can be provided. By providing such a carrying-in means and a carrying-out means, the object to be processed can be continuously subjected to a discharge treatment.

FIG. 2 shows another embodiment of the apparatus of the present invention. FIG.
In the discharge treatment device 10, the columnar electrode 1a carries a hollow cylindrical dielectric layer 2a on the side wall. The cylindrical electrode 1a and an electrode 1b (not carrying a dielectric layer) curved into a concave curved surface corresponding to the convex curved surface of the cylindrical electrode 1a are opposed to each other at a predetermined interval. A processing space 15 disposed between the surface of the dielectric layer 2a curved in a convex shape and the surface of the electrode 1b curved in a concave shape,
The object 5 can be supplied to the processing space 15. The cylindrical electrode 1a is grounded via an earth wire 12 and the concavely curved electrode 1b is connected to an AC high voltage power supply 3 via a conducting wire 13 so that a voltage can be applied between the electrodes 1a and 1b. Have been. Further, in the processing space 15 formed between the two electrodes, a gas ejection device 4 capable of passing gas at a speed of 10 m / sec or more is arranged. That is, the gas ejection device 4 is provided with the ventilation pipe 4a.
The opening 4b is opened substantially at the center of the concavely curved electrode 1b and connected to the processing space 15. Note that a gas suction device can be used instead of or in addition to the gas ejection device 4.

As described above, the shape of the electrodes constituting the discharge treatment apparatus of the present invention is not particularly limited, and a combination of flat electrodes as shown in FIG. 1 and a cylindrical electrode as shown in FIG. And various shapes such as a combination with a corresponding concave curved electrode or a combination of a convex spherical electrode and a corresponding concave spherical electrode, and the combination is not particularly limited. When a cylindrical electrode and a curved electrode are combined as shown in FIG. 2, discharge processing can be continuously performed while supplying an object to be processed relatively stably.

In the embodiment shown in FIG. 2, only the cylindrical electrode 1a carries a dielectric layer. However, the dielectric layer can be carried only by the concave curved electrode 1b. 1b can carry a dielectric layer. Further, when the object to be processed is a film, since the film itself acts as a dielectric, it may not be necessary for any electrode to carry a dielectric layer.

Gas may be ejected or sucked from a direction parallel to the electrode (FIG. 1), or gas may be ejected or sucked from a direction perpendicular to the electrode (FIG. 2) to the electrode. An air current may be generated in a parallel direction (the direction shown by arrows A and B in FIG. 2 or the opposite direction), or a gas may be ejected or sucked from a direction that is neither parallel nor perpendicular to the electrode. May be generated in a direction parallel to the air flow.

Further, when gas is ejected or sucked in a direction perpendicular to the cylindrical electrode 1a as shown in FIG. 2, the gas flows in a direction parallel to the electrode (the direction shown by arrows A and B in FIG. Flows in the opposite direction, but seals between one electrode so as to prevent gas from passing (for example, a roll 16 between the electrodes).
May be arranged). Thus, by closing one, the flow rate of the passing gas can be reduced to about half at the same flow rate. In this case, gas does not flow in the direction between the closed electrodes, and in this direction, the cooling effect of the object to be processed, the cooling effect of the atmosphere in the discharge processing space, and the uniformizing effect of the discharge cannot be obtained. It is preferable not to apply an AC high voltage between the electrodes so that no discharge occurs in the processing space 15 between the closed electrodes. In addition, the discharge processing apparatus 10 shown in FIG. 2 has the shape of the electrode, that the dielectric layer is carried on only one electrode,
The discharge processing apparatus is exactly the same as the discharge processing apparatus of FIG.

FIG. 3 shows still another embodiment of the apparatus of the present invention.
In the discharge processing apparatus 10 of FIG. 3, a pair of flat electrodes 1a,
1b are disposed so as to face each other at a predetermined interval, and come into contact with both of the plate-shaped electrodes 1a and 1b. The through-hole processing space 1 has a rectangular parallelepiped shape, and has a rectangular parallelepiped shape in the center.
5 is disposed. In this discharge processing apparatus 10, a through-hole processing space 15 is provided inside the dielectric layer 2, and the object 5 can be disposed inside the through-hole processing space 15. One of the flat electrodes 1a is connected to the AC high-voltage power supply 3 via a conducting wire 13 so that a voltage can be applied between the flat electrodes 1a and 1b.
And the other flat electrode 1b is grounded via a ground wire 12. Further, a gas ejecting device 4 is provided which can pass gas at a speed of 10 m / sec or more through a ventilation pipe 4 a into a through-hole processing space 15 formed inside the dielectric layer 2. Note that a gas suction device may be used instead of or in addition to the gas ejection device 4.

In the discharge treatment apparatus 10 of the embodiment shown in FIG. 3, the through-hole treatment space 15 is tubular. That is, the through-hole processing space 15 has a side wall, and is opened only at the gas inlet and the gas outlet. Alternatively, the processing space is
As shown in FIG. 1, it may be an open system (that is, the processing space has no side wall). In addition, when a dielectric material having a rectangular parallelepiped shape or a cylindrical shape having a through-hole processing space 15 therein is used, gas generated by a gas ejection device or a gas suction device is efficiently passed between a pair of electrodes without being scattered. be able to. Although not particularly shown in the discharge processing apparatus 10 in FIG. 3, a unit (for example, a pair of rolls) that can carry in and carry out the object 5 to and from the through-hole processing space 15 may be provided. By providing such a carrying-in means and a carrying-out means, the object to be processed can be continuously subjected to a discharge treatment. The discharge processing apparatus 10 of FIG. 3 is basically the same as the discharge processing apparatus of FIG. 1 except that the outer shape is a rectangular parallelepiped as a dielectric and has a through-hole processing space. In the discharge treatment apparatus of the present invention, as shown in FIG. 1, when one dielectric layer and the other dielectric layer are separated from each other, 1
Alternatively, a plurality of spacer materials can be inserted between the dielectric layers to form sidewalls of the processing space. In the discharge treatment apparatus of such an embodiment, the object to be treated is also shown in FIG.
The processing can be performed in the same manner as the discharge processing apparatus 10 of the embodiment shown in FIG.

The discharge treatment method of the present invention can be carried out by using the discharge treatment device according to the present invention as described above. That is, in a state where the object to be processed is arranged between the two electrodes, an AC high voltage is applied between the two electrodes, and a gas mainly composed of air flows into the space formed by the two electrodes at a speed of 10 m / m. This is a method in which the discharge generated between the two electrodes is caused to act on the object to be processed by passing the same for at least seconds. The object to be subjected to the discharge treatment in the present invention is not particularly limited, and examples thereof include a fiber sheet (for example, a woven fabric, a knitted fabric, a nonwoven fabric, or a composite thereof), a microporous film, a foam, a film, and a fiber. Or a resin molded product. Note that the object to be processed may be made of an inorganic material, may be made of an organic material, or may be made of both an inorganic material and an organic material. In particular, according to the discharge treatment method of the present invention, there is a feature that even a target to be processed made of an organic material can be processed at a high speed or a roughened surface without damaging the target to be processed.

When the object to be processed is arranged between a pair of electrodes arranged opposite to each other, as described above, the object can be arranged in any state as long as it does not hinder the passage of gas in the processing space. As shown in FIG. 1, one of the two dielectric layers 2a and 2b may be placed on one of the dielectric layers 2a and 2b in a non-contact state with the other dielectric layer 2a. It can be arranged so as to be in contact with, or such that a part of the object to be processed 5 is in contact with the dielectric layer 2a and / or the dielectric layer 2b.

Next, an AC high voltage is applied between the two electrodes. The waveform of this voltage is not particularly limited.
For example, it may be a sine waveform, a pulse waveform, a rectangular waveform, or the like. Among these, if it is a pulse waveform,
This is preferable because the discharge can be made more uniform. In the case of this pulse waveform, the rise time and the fall time are each preferably 2 μsec (microsecond) or less, more preferably 0.5 μsec or less, and even more preferably 0.2 μsec or less. The polarity of the voltage is not particularly limited, and may be unipolar or bipolar.
It is preferable that the polarity is bipolar in terms of high processing efficiency.

The applied voltage is not limited because it varies depending on the distance between the electrodes (distance including the thickness of the dielectric layer) and the atmosphere around the electrodes, but is not limited to 2 KVp or more so as to easily generate discharge. And more preferably 5 KVp or more. On the other hand, the upper limit of the applied voltage is not limited as long as the voltage does not cause damage to the object to be processed, but about 100 KVp is appropriate. The electric field strength is not particularly limited as long as it does not damage the dielectric or the object to be processed, and is not particularly limited, but is 10 to 500 KVp / cm.
And more preferably 20 to 300 KVp / cm.

The frequency is preferably 1 kHz to 5 kHz.
00 KHz, more preferably 10 KHz to 200 KHz
It is. If the frequency is less than 1 KHz, the time required for the discharge treatment tends to be long, and if it exceeds 500 KHz, the object to be processed and the dielectric may be destroyed by overheating due to dielectric heating. Further, the applied power is 2.5 W /
cm ² or more, and more preferably 5 W / cm ² or more. Note that the upper limit of the applied power is not particularly limited because it varies depending on the gas flow velocity, flow rate, and the like.

Such a voltage may be applied continuously or intermittently. In the case of intermittent application, the number of repetitions per second is preferably within the above range. That is, the number of repetitions per second is 1,000
Preferably it is ~ 500,000 times, 10,000
More preferably, it is 200,000 times. The application time of such an AC high voltage is not limited because it varies depending on the type of the object to be processed, the speed of the gas, the applied power, and the like.
The discharge treatment can be completed in a short time of substantially 1 sec (second) or less for a porous material such as a non-woven fabric.

As described above, while applying the AC high voltage,
The space formed by both electrodes, that is, the object to be processed is both electrodes (dielectric layer if a dielectric layer is carried)
If not, two spaces formed between the object and the electrode (or the dielectric layer), the object is in contact with only one electrode (or the dielectric layer) in case of,
1 formed between an object to be processed and an electrode (or a dielectric layer)
A gas is passed through the two spaces at a speed of 10 m / sec or more, and a discharge is generated between the two electrodes to process the object.
If the passage speed is less than 10 m / sec, the cooling effect of the object to be processed, the cooling effect of the atmosphere in the discharge processing space, and the uniforming effect of the discharge may be reduced. A more preferred passage speed is 85 m / sec or more, and a still more preferred passage speed is 100 m / sec or more. In addition,
Although the upper limit is not particularly limited, it is 1,000 m /
Seconds are appropriate. In particular, when the waveform of the AC high voltage is a sine wave, the speed at which the gas passes is 85 m / s.
ec or more, more preferably 100 m / sec or more. When the waveform of the AC high voltage is a pulse wave, the speed at which the gas passes is 10 m / s.
ec or more is sufficient. The passing speed of this gas is
Regardless of the waveform of the AC high voltage, it is preferable that the higher the applied power, the higher the speed.

The gas can be cooled. When the gas is cooled in this way, it is preferable that the gas does not liquefy. For example, when cooling air, it is preferable to cool so as not to generate water droplets, and if it does, it is preferable to remove water.

The gas passing through the space formed between the pair of electrodes is not particularly limited as long as it is a gas mainly composed of air, and is preferably air itself. Examples of the gas that can be mixed with air include a gas for stabilizing discharge (for example, a rare gas or nitrogen) or a reactive gas for introducing a functional group.

As the rare gas, for example, helium, neon, argon, krypton, xenon, radon, or the like can be used. The reactive gas is not limited as long as it is a gas capable of introducing a desired functional group. For example, an oxygen-containing compound gas, a nitrogen-containing compound gas, a sulfur-containing compound gas, a phosphorus-containing compound gas, or the like may be used alone. Or mixed and used. Further, an organic compound gas such as alcohol or ketone may be mixed with these gases.

When imparting hydrophilicity to the object to be treated, it is preferable to use an oxygen-containing compound gas and / or a sulfur-containing compound gas. As the oxygen-containing compound gas, for example, oxygen, air, carbon monoxide, carbon dioxide and the like can be used. As the sulfur-containing compound gas, for example, hydrogen sulfide, sulfur monoxide, sulfur dioxide, sulfur trioxide, sulfur trioxide, Disulfur oxide, sulfur heptoxide and the like can be used. Note that the discharge treatment method of the present invention is preferable because discharge can be generated at a pressure higher than the atmospheric pressure and the discharge treatment can be continuously performed. Of course, it may be carried out under reduced pressure or under pressure. Further, the pressure may be changed or constant, and when it is changed, it may be changed continuously or discontinuously.

[0042]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of a discharge treatment method using the discharge treatment apparatus of the present invention will be described below, but the present invention is not limited to the following embodiments.

Example 1 A polyester film having a thickness of 100 μm was prepared as the object 5 to be processed. In addition, as a processing device,
The apparatus shown in FIG. 1 (however, the electrode 1b does not carry a dielectric layer) was used. Specifically, a flat aluminum electrode 1a carrying a non-porous alumina dielectric layer 2a (thickness = 2 mm) (coated with silicone rubber from the periphery of the opposing surface to the side wall 11a) and a flat aluminum electrode 1b
(Which does not carry a dielectric layer) and a pair of electrodes disposed to face each other with an interval of 0.5 mm (the distance between the opposing surface of the alumina dielectric layer 2a and the opposing surface of the flat aluminum electrode 1b). An electrode, an AC high-voltage power supply 3 connected to the aluminum electrode 1a via a conducting wire 13, and a ground wire 12 connected to the aluminum electrode 1b, and an air flow is blown from a direction parallel to the two electrodes. A discharge treatment device provided with a gas ejection device 4 and a vent pipe 4a that can perform the discharge was prepared. Next, the polyester film was disposed on the aluminum electrode 1b of the discharge treatment device. Next, the pressure at the discharge processing space outlet is reduced to the atmospheric pressure (pressure =
Constant), air flow (temperature = 20 ° C) between both electrodes about 70m
/ Sec, and at the same time, an AC high voltage (bipolar; sine waveform; frequency = about 50 kHz; applied voltage = about 9.5 kVp; applied power = 8 W / cm ² ) from the power supply 3 is applied to about 0.
A discharge was generated by applying the voltage continuously for 5 seconds, and the polyester film was subjected to a discharge treatment. Before the discharge treatment, the polyester film was formed by immersing the polyester film in water and then pulling up the water to repel water to form a polka dot on the polyester film. When pulled up after being immersed in water, the water spread over the entire polyester film surface and did not form polka dots. Further, the polyester film after the discharge treatment shrank more than before the discharge treatment.

[0043]

Embodiment 2 Under the discharge treatment conditions, (1) the passing speed of the air stream was set to about 100 m / sec, (2) the applied power was applied so as to be 10 W / cm ² , and (3) the alternating current A film similar to the polyester film used in Example 1 was discharged by repeating the operation described in Example 1 except that the high voltage application time was set to about 0.1 second. Before the discharge treatment, the polyester film was formed by immersing the polyester film in water and then pulling up the water to repel water to form a polka dot on the polyester film. When pulled up after being immersed in water, the water spread over the entire polyester film surface and did not form polka dots. The polyester film after the discharge treatment did not shrink as compared to before the discharge treatment.

[0044]

Example 3 By repeating the operation described in Example 1 except that the AC high voltage application time was set to about 2 seconds,
A film similar to the polyester film used in Example 1 was subjected to a discharge treatment. Before the discharge treatment, the polyester film was formed by immersing the polyester film in water and then pulling up the water to repel water to form a polka dot on the polyester film. When pulled up after being immersed in water, the water spread over the entire polyester film surface and did not form polka dots. Further, the polyester film after the discharge treatment shrank more than before the discharge treatment, and the degree was larger than that in Example 1. FIG. 6 shows the results of observing the surface of the polyester film before the discharge treatment with an electron micrograph.
FIG. 7 shows the results of observing the surface of the polyester film after the discharge treatment with an electron micrograph. As shown in FIG. 6 and FIG. 7, it was found that irregularities were formed on the film surface by the discharge treatment, and the film was roughened.

[0045]

Embodiment 4 Under the discharge treatment conditions, (1) the passing speed of the air flow was set at about 150 m / sec, (2) the applied power was applied to be 13 W / cm ² , and (3) the alternating current A discharge treatment was performed on the same film as the polyester film used in Example 1 by repeating the operation described in Example 1 except that the high voltage application time was set to about 2 seconds. Before the discharge treatment, the polyester film was formed by immersing the polyester film in water and then pulling up the water to repel water to form a polka dot on the polyester film. When pulled up after being immersed in water, the water spread over the entire polyester film surface and did not form polka dots. The polyester film after the discharge treatment did not shrink as compared to before the discharge treatment. When the surface of the polyester film after the discharge treatment was observed by an electron micrograph,
As in the case of Example 3, it was found that irregularities were formed on the film surface and the film was roughened.

[0046]

Comparative Example 1 A film similar to the polyester film used in Example 1 was subjected to discharge treatment by repeating the operation described in Example 1 except that no air flow was passed. However, the polyester film melted and deformed.

[0047]

Comparative Example 2 Under the discharge treatment conditions, (1) no air flow was passed, (2) the applied power was applied so as to be 1 W / cm ² , and (3) the AC high voltage application time was A film similar to the polyester film used in Example 1 was subjected to a discharge treatment by repeating the operation described in Example 1 except that the time was set to about 0.5 second. This polyester film was not melted by the electric discharge treatment, but before and after the electric discharge treatment, the polyester film was repelled after being immersed in water, and the polyester film was partially repelled by water, Polka dots were formed on the film.

[0048]

Embodiment 5 A nonwoven fabric obtained by subjecting a fiber web formed of polyethylene / polypropylene 17-split fibers by a wet method to a hydroentanglement treatment and splitting it into polyethylene ultrafine fibers and polypropylene ultrafine fibers (area density = 7)
5 g / m ² , thickness = about 0.2 mm). Next, under the discharge processing conditions, (1) the applied power is 6 W / c
The nonwoven fabric was subjected to a discharge treatment by repeating the operation described in Example 1 except that the application was performed so as to obtain m ² and (2) the AC high voltage application time was set to about 1.5 seconds. Before discharge treatment, the nonwoven fabric did not readily absorb water droplets, but after discharge treatment, absorbed instantly when water droplets were dropped. Further, the nonwoven fabric after the discharge treatment was slightly shrunk than before the discharge treatment.

[0049]

Embodiment 6 Under the discharge treatment conditions, (1) the passing speed of air was set to 150 m / sec, (2) the applied power was applied to be 8 W / cm ² , and (3) the high AC voltage was applied. By repeating the operation described in Example 5 except that the application time was set to about 1 second, a nonwoven fabric similar to the nonwoven fabric used in Example 5 was subjected to discharge treatment. Before discharge treatment, the nonwoven fabric did not readily absorb water droplets, but after discharge treatment, absorbed instantly when water droplets were dropped. The nonwoven fabric after the discharge treatment did not shrink as compared to before the discharge treatment.

[0050]

Example 7 By repeating the operation described in Example 6 except that the air passing speed was set to 100 m / sec, a nonwoven fabric similar to the nonwoven fabric used in Example 5 was subjected to discharge treatment. Before discharge treatment, the nonwoven fabric did not readily absorb water droplets, but after discharge treatment, absorbed instantly when water droplets were dropped. The nonwoven fabric after the discharge treatment did not shrink as compared to before the discharge treatment.

[0051]

Example 8 A nonwoven fabric similar to the nonwoven fabric used in Example 5 was subjected to a discharge treatment by repeating the operation described in Example 6 except that the air passing speed was 80 m / sec. Before discharge treatment, the nonwoven fabric did not readily absorb water droplets, but after discharge treatment, absorbed instantly when water droplets were dropped. In addition, a hole was formed in a very small part of the nonwoven fabric by the discharge treatment.

[0052]

Comparative Example 3 A nonwoven fabric similar to the nonwoven fabric used in Example 5 was subjected to discharge treatment by repeating the operation described in Example 5 except that air was not passed. However, the nonwoven fabric melted violently.

[0053]

Comparative Example 4 A nonwoven fabric similar to the nonwoven fabric used in Example 5 was subjected to a discharge treatment by repeating the operation described in Example 5 except that the air passing speed was about 8 m / sec. However, the nonwoven fabric has melted.

[0054]

Embodiment 9 Under the discharge treatment conditions, (1) the air passing speed was 12 m / sec, and (2) the rise time and the fall time were 0.4 microsecond (μsec).
And that a pulse waveform voltage having a pulse width of about 1 microsecond (μsec) was applied. (3) The applied power was 3 W / cm ²
And (4) the non-woven fabric similar to the non-woven fabric used in Example 5 by repeating the operation described in Example 5 except that the application time of the AC high voltage was set to about 5 seconds. Was discharged. Before discharge treatment, the nonwoven fabric did not readily absorb water droplets, but after discharge treatment, absorbed instantly when water droplets were dropped. The nonwoven fabric after the discharge treatment did not shrink as compared to before the discharge treatment.

[0055]

Comparative Example 5 A nonwoven fabric similar to the nonwoven fabric used in Example 5 was subjected to discharge treatment by repeating the operation described in Example 9 except that air was not passed. However, considerable holes were found in the fibers constituting the nonwoven fabric.

[0056]

Comparative Example 6 A nonwoven fabric similar to the nonwoven fabric used in Example 5 was subjected to discharge treatment by repeating the operation described in Example 9 except that the air passing speed was set to about 7 m / sec. However, holes in which the fibers constituting the nonwoven fabric were melted were partially observed.

[0057]

Example 10 A core-sheath type composite fiber (fineness = 1.4 dtex, fiber diameter = about 14 μm) having polypropylene as a core component and polyethylene as a sheath component was prepared as an object to be treated. Next, under the discharge treatment conditions, (1) the air passing speed was set to 250 m / sec, (2) the applied power was applied to be 13 W / cm ² , and (3) the AC high voltage application time was changed. Except for about 4 seconds, the operation described in Example 1 was repeated to discharge the core-sheath type composite fiber. The core-sheath composite fibers after the discharge treatment were not shrunk as compared with before the discharge treatment. The results of observing the surface of the core-sheath composite fiber after the discharge treatment by an electron micrograph are shown in FIG. 8 (before the discharge treatment) and FIG. 9 (after the discharge treatment). As shown in FIGS. 8 and 9, severe irregularities were formed by the discharge treatment, and it was confirmed that the fiber surface area was increased. That is, it was confirmed that the surface was roughened.

[0058]

Comparative Example 7 The procedure of Example 10 was repeated except that the air was not passed.
A fiber similar to the core-sheath type composite fiber used in the above was subjected to discharge treatment. However, the core-sheath composite fiber was completely melted.

[0059]

Example 11 A melt-blown nonwoven fabric made of polypropylene (area density = 30 g / m ² ; average fiber diameter = 2 μm) was prepared as an object to be treated. Next, under the discharge treatment conditions, (1) the applied power was applied to be 6 W / cm ² , (2) the AC high voltage application time was about 1.5 seconds, and (3) the passage of air Speed of 95m / sec
The procedure described in Example 1 was repeated to discharge the melt-blown nonwoven fabric. Before the discharge treatment, the nonwoven fabric did not readily absorb water drops, but after the discharge treatment,
When a water drop was dropped, it was absorbed instantly. Also,
This nonwoven fabric did not shrink due to the discharge treatment.

[0060]

Embodiment 12 Under the discharge processing conditions, the applied power is 8 W
/ Cm except the applied that as ² become, Example 11
The discharge treatment was performed on the nonwoven fabric similar to the melt-blown nonwoven fabric used in Example 11 by repeating the operation described in Example 1. Before discharge treatment, the nonwoven fabric did not readily absorb water droplets, but after discharge treatment, absorbed instantly when water droplets were dropped. The nonwoven fabric did not shrink due to the discharge treatment.

From the results of Examples 1 to 12 and Comparative Examples 1 to 7, when a gas is passed at a speed of 10 m / sec or more, a discharge treatment is performed at a high discharge energy density without damaging the object to be processed. It can be seen that the surface can be roughened. In particular, it is also found that when the AC high voltage has a pulse waveform, it is preferable to pass the gas at 10 m / sec or more, and otherwise (for example, a sine waveform), it is preferable to pass the gas at 85 m / sec or more. Was.

[0062]

According to the discharge treatment apparatus of the present invention, even when the discharge energy density is increased, the object to be treated can be treated stably at a high speed without damaging the object to be treated, and the surface is roughened by increasing the discharge energy density. can do. Further, since the discharge energy density can be increased, there is also an effect that the size of the discharge unit can be reduced. The above-mentioned effect is remarkable when a means capable of applying an AC high voltage having a pulse waveform between the two electrodes is provided. Further, the above-mentioned effect is remarkable when the space formed by the two electrodes is provided with a means capable of passing gas at a speed of 85 m / sec or more.

According to the discharge treatment method of the present invention, even if the discharge energy density is increased, the discharge treatment can be performed stably at a high speed without damaging the object to be treated, and the surface is roughened by increasing the discharge energy density. Can be. The above effect is remarkable when an AC high voltage having a pulse waveform is applied between the two electrodes. Further, the above-mentioned effect is remarkable when gas is passed through the space formed by the two electrodes at a speed of 85 m / sec or more.

[Brief description of the drawings]

FIG. 1 is a schematic cross-sectional view of one embodiment of a discharge treatment apparatus according to the present invention.

FIG. 2 is a schematic sectional view of another embodiment of the electric discharge treatment apparatus of the present invention.

FIG. 3 is a schematic cross-sectional view of still another embodiment of the discharge treatment apparatus of the present invention.

FIG. 4 is an example of a pulse waveform.

FIG. 5 is another example of a pulse waveform.

FIG. 6 is an electron micrograph instead of a drawing showing a polyester film surface state before a discharge treatment in Example 3.

FIG. 7 is an electron micrograph instead of a drawing showing the surface state of the polyester film after the discharge treatment in Example 3.

FIG. 8 is an electron micrograph instead of a drawing showing a fiber surface state before a discharge treatment in Example 10.

FIG. 9 is an electron micrograph instead of a drawing showing a fiber surface state after discharge treatment in Example 10.

[Explanation of symbols]

1a, 1b ... electrodes; 2, 2a, 2b ... dielectric layers; 3 ... AC high-voltage power supply; 4 ... gas ejection device;
a ... vent pipe; 4b ... vent pipe opening;
Object to be processed 10: Discharge treatment device; 11a, 11b,.
-Flat electrode side wall; 12 ... ground wire; 13 ... lead wire; 15 ... processing space; 16 ... roll.

Claims (6)

[Claims] 1. A pair of electrodes arranged opposite to each other, means for applying an AC high voltage between the two electrodes, and a space formed between the two electrodes mainly composed of air. Means for passing gas at a speed of 10 m / sec or more. 2. The discharge processing apparatus according to claim 1, further comprising: means for applying an AC high voltage having a pulse waveform between the two electrodes. 3. A space formed between the two electrodes,
3. A means for passing a gas mainly composed of air at a speed of 85 m / sec or more.
The discharge treatment device according to claim 1. 4. In a state where an object to be processed is disposed between a pair of electrodes disposed opposite to each other, an AC high voltage is applied between the two electrodes, and air is supplied to a space formed between the two electrodes. A discharge gas generated between the two electrodes is caused to act on the object to be processed by passing a gas mainly composed of a gas at a speed of 10 m / sec or more. 5. The discharge processing method according to claim 4, wherein an AC high voltage having a pulse waveform is applied between said two electrodes. 6. A space formed between the two electrodes,
The discharge treatment method according to claim 4 or 5, wherein a gas mainly composed of air is passed at a speed of 85 m / sec or more.