JP3455610B2 - Method and apparatus for modifying porous body - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for modifying the surface and inner surface of a porous body, and more particularly to a method and a device for hydrophilizing the surface and inner surface of a sheet-shaped porous body made of a hydrophobic material. Regarding the device.

[0002]

2. Description of the Related Art Various methods disclosed below are disclosed as methods for modifying films and porous bodies of fluororesins such as polytetrafluoroethylene and polyvinylidene fluoride, thermoplastic resins such as polyethylene, polypropylene and polysulfone. Has been done. (A) For example, a fluororesin is dipped in a liquid ammonia containing metallic sodium or a treatment liquid such as naphthalene and tetrahydrofuran, or a polyethylene or polypropylene resin is dipped in a mixed liquid of potassium dichromate and concentrated sulfuric acid. Method of chemically modifying the surface (b) Modification method by sputter etching or several kHz
Plasma treatment reforming method (c) applying a surfactant by applying a frequency voltage of 10 to generate plasma between the electrode and the object to be treated

[0003]

In the above-mentioned conventional example, first, in the modification method (a), in the case of a fluororesin, the surface of the fluororesin material becomes brown and the surface portion becomes brittle. However, there is a problem that only the immersed portion can be modified. Furthermore, it was difficult to control the reaction, and required dangerous chemicals.

In the method (b), only the surface can be modified, and the plasma treatment generates plasma between the electrode and the object to be treated, so that the treatment up to the inner surface of the porous body cannot be performed.

Further, in the method (c), since the surfactant does not sufficiently adhere to the porous body, the surfactant is likely to fall off and it is difficult to maintain the hydrophilicity. The present invention has been made to solve these problems, and provides a method for modifying a porous body and an apparatus therefor capable of easily and uniformly modifying the surface and the inner surface of the porous body. With the goal.

[0006]

In order to achieve the above object, the method of the present invention has a voltage applying electrode for applying a voltage and a ground electrode, and a plurality of holes internally provided between the electrodes. A method for treating the porous body by disposing the porous body with the porous body interposed therein, introducing a reaction gas into the chamber, and applying a voltage to the voltage application electrode to generate plasma. In the above, the inside of the chamber is set to atmospheric pressure or higher, and high frequency / high voltage is applied to the voltage application electrode to generate high density plasma on the surface of the porous body and the internal space of each hole. There is.

Further, in this method, it is preferable to fix a dielectric to both the electrodes or one of the electrodes. Further, the device of the present invention comprises a chamber, a reaction gas introducing means for introducing a reaction gas into the chamber, and a voltage applying electrode and a ground electrode which are arranged to face each other in the chamber, and between the both electrodes. Introducing a reaction gas in the state of interposing a porous body, by applying a voltage to the voltage applying electrode, in the apparatus for processing the porous body, the chamber is an atmosphere of atmospheric pressure or higher, A high frequency / high voltage is applied to the voltage application electrode, and the voltage application electrode is characterized by being provided with an adjusting means for adjusting the distance between the both electrodes.

Further, this apparatus may be provided with a feeding means for feeding the sheet-shaped porous body while moving between the electrodes in a predetermined direction, and a winding means for winding the fed porous body.

Furthermore, it is preferable that a dielectric is fixed to both electrodes or one of the electrodes.

[0010]

[Function] In plasma, neutral molecules, electrons, and ions repeat collisions to transfer energy, and in addition to ionization, excitation, and dissociation, electron attachment and recombination, and a combination of these reactions occur. .

In the method for treating a porous body of the present invention, since the treatment is carried out under a high pressure equal to or higher than atmospheric pressure, the density of gas molecules becomes high and the mean free path of gas molecules becomes short. When a high-frequency strong electric field is formed in this state, high-density collisions are repeated in the minute space inside the hole with the radicals generated by collisions of electrons and ions, and plasma is generated. Further, since the high frequency is used, the amplitude of ions and electrons can be reduced and the plasma region can be concentrated, and as a result, high density plasma can be generated.

By fixing the dielectric to both electrodes or one of the electrodes, it is possible to prevent the occurrence of arc discharge when the electrodes are applied, and it is possible to maintain stable plasma. In the apparatus for processing a porous body of the present invention, which is a means for achieving the above method, if the atmosphere in the chamber is at a high pressure of atmospheric pressure or higher and plasma is generated at a high frequency / high voltage, the porous body High-density plasma is formed near the body. Also, the adjusting means can adjust the distance between both electrodes in accordance with the thickness of the porous body, and can set an appropriate distance for obtaining a strong electric field for each treatment.

Further, the sheet-shaped porous body can be continuously processed by the feeding means and the winding means. Further, the dielectric fixed to both electrodes or one of the electrodes can prevent the occurrence of arc discharge when the electrodes are applied, and can maintain stable plasma.

[0014]

Embodiments of the method and the device of the present invention will be described below with reference to the drawings. The method of the embodiment of the present invention is
For example, it can be performed using the device shown in FIGS. 1 to 5 described later.

The method according to the embodiment of the present invention is characterized in that a voltage application electrode for applying a voltage and a ground electrode are placed in a chamber in which a pressure is equal to or higher than atmospheric pressure with a porous body interposed therebetween. The reaction gas is introduced into the chamber,
The high-frequency / high-voltage is applied to the voltage application electrode to generate plasma, thereby modifying the porous body.

In order to generate the above-mentioned plasma, a strong electric field is required in the plasma generating part. As a method for obtaining this strong electric field, for example, the shape of the voltage applying electrode is made to be a projection shape so as to concentrate the electric field, or a method of increasing the electric field strength by narrowing the interval between the voltage applying electrode and the ground electrode which are arranged opposite to each other. There is.

As a method of promoting plasma generation inside the pores of the porous body, there is a method of filling the outside of the porous body with a gas having a high ionization voltage. Therefore, examples of the inert gas to be introduced include helium, argon, neon, krypton, xenon, nitrogen, and the like, and a mixed gas obtained by mixing these gases. Among these, helium and argon are preferable from the viewpoint of discharge stability.

Further, in order to add hydrophilicity or lipophilicity to the porous body, an organic compound which is liquid or gas at room temperature is used. First, when hydrophilicity is added, for example, organic solvents such as alcohols and ketones, and mixtures thereof are used. The alcohols include ethanol, methanol, isopropyl alcohol, isobutyl alcohol, etc., and the ketones include dimethyl ketone, acetone, methyl ethyl ketone, etc.

On the other hand, when lipophilicity is added, for example, aromatic hydrocarbons such as xylene, benzene, toluene, styrene, etc., aliphatic hydrocarbons such as propane, butane, pentane, hexane, ethylene, butene, pentene, etc. There are hydrocarbons such as unsaturated aliphatic hydrocarbons.

The mixing ratio of the reaction gas varies depending on the selected gas or organic compound, but the inert gas is from 60% by volume to 99.5% by volume, the gas is a gas at room temperature or the organic compound is a gas or liquid at room temperature. Is 0 in the gaseous state.
It is preferable that the amount is from 5% by volume to 40% by volume.

The electrodes facing each other are arranged in parallel with each other, and a porous body to be processed is arranged between both electrodes. The distance between both electrodes can be adjusted according to the thickness of the porous body, and the gap between the voltage application electrode and the porous body is set to 1 mm or less, and preferably adjusted so as to be in contact with each other. In addition, the material forming these both electrodes is not particularly limited as long as it shows conductivity, and examples thereof include copper, nickel, aluminum, tungsten, magnesium, manganese, and the like. Metal alloys are available.

Further, it is preferable to dispose a dielectric in one or both of the gaps between the opposing electrodes and the porous body. This is because by disposing this dielectric, it is possible to prevent the occurrence of arc discharge when a voltage is applied, and it is possible to maintain stable plasma. Examples of the substance that constitutes this dielectric include glass, alumina, mica, polyester, polyimide, and Teflon.

As the porous body treated by the above method, a sheet-like porous body having pores having a diameter of 0.01 μm to 1 mm, a porosity of 5% to 98% and a thickness of 1 μm to 10 mm is used. Preference is given to using. Further, the substance constituting this porous body is not particularly limited, but examples thereof include polytetrafluoroethylene, polyvinylidene fluoride, tetrafluoroethylene-hexafluoroalkyl vinyl ether copolymer, and tetrafluoroethylene-ethylene copolymer. Polymer, tetrafluoroethylene
-Fluorine polymer film made of perfluoroalkyl vinyl ether copolymer, polychlorotrifluoroethylene, etc., ceramics such as alumina, silicon carbide, silicon nitride, zirconia, glass, polyethylene, polypropylene, polystyrene, polyimide, etc. Thermoplastic resin.

Next, an embodiment of the device of the present invention will be described with reference to FIGS. 1 to 5 which schematically show the structure thereof. First, the apparatus of the embodiment shown in FIG. 1 is provided with a processing chamber 10 and a reaction gas introduction port 1 for introducing a reaction gas or the like from the outside of the processing chamber 10 drawn into the processing chamber 10. Further, the gas exhaust port 7 for exhausting the gas in the processing chamber 10 has a processing chamber 10
Is connected to an exhaust mechanism (not shown) through the wall surface of the.

A cylindrical voltage applying electrode 2 connected to the high frequency power source 8 through an electrode connecting joint 9 is provided in the processing chamber 10, and the voltage applying electrode 2 is arced when a voltage is applied. A dielectric 3 is connected to prevent discharge from occurring. A ground electrode 5 is arranged so as to face the voltage applying electrode 2. An elevating table 6 for elevating and lowering the ground electrode 5 is provided below the ground electrode 5, and the porous body 4 to be modified is provided on the ground electrode 5.
Is placed. At the time of processing, by driving the elevating table 6 according to the thickness of the porous body 4, the ground electrode 5 and the dielectric 3
The interval between and can be set.

When processing is performed by the apparatus of this embodiment,
The distance between the porous body 4 and the dielectric 3 and the distance between the porous body 4 and the ground electrode 5 are each 1 mm or less, but it is preferable that they are in contact with each other.

In this embodiment, the elevating table 6 is provided on the ground electrode 5 side as a means for adjusting the distance between both electrodes, but the present invention is not limited to this and may be provided on both electrodes. It may be provided on the voltage applying electrode 2 side.

In this state, a mixture of an inert gas and at least one substance selected from the group consisting of oxygen, hydrogen, water, and an organic compound which is liquid or gas at room temperature into the chamber 10 through the reaction gas inlet 1. By introducing a reaction gas containing the reaction gas into the porous body 4, a high frequency / high voltage is applied to the voltage application electrode 2 to generate plasma inside the porous body 4, The surface and the inner surface of the body 4 are treated.

Here, three specific examples of the hydrophilization treatment carried out by using this apparatus are given, and the results of examining the respective treatment conditions and the hydrophilization evaluation are shown in Table 1.

[0030]

[Table 1]

In each of these specific examples, a high frequency / high voltage having a frequency of 145 MHz is applied, and
Alumina was used as the dielectric 3. Also,
The evaluation of the hydrophilization performed here is to measure a time until a water droplet having a diameter of 2 mm is dropped on the hydrophilized porous film and the water droplet penetrates into the porous film. In addition, as a result of performing the same evaluation on the untreated porous film, the contact angle of water was 135 in both cases.
The water droplet did not soak into the porous film as it was.

Although the apparatus shown in FIG. 1 and the processing method using this apparatus have been described above, the apparatus shown in FIG. 2 is another apparatus configuration. This apparatus is designed to process the porous film 15 in order to continuously process the porous film 15.
A delivery roll 11 for delivering the product and a take-up roll 12 for winding the treated porous film 15 are provided. Further, a plurality of dielectric tubes 13 are rotatably provided on the voltage applying electrode 2 side via a dielectric 3, and a metal wire 14 is inserted in each dielectric tube 13. The metal wire 14 is electrically connected to the voltage applying electrode 2 and does not rotate in synchronization with the rotating operation of the dielectric tube 13. The diameter of the dielectric tube 13 is larger than the diameter of the metal wire 14, and the dielectric tube 13 is arranged in contact with the porous film 15 during the reforming process. After the modification process, the ground electrode 5 and the dielectric tube 13 rotate in opposite directions, and
The porous film 15 is sequentially wound by the winding roll 12, so that the porous film 15 is conveyed. This conveying operation is performed by the delivery mechanism 11 rotating the take-up roll 12 so that the delivery roll 11 and the dielectric tube 13 follow and rotate.

As described above, according to the apparatus shown in FIG. 2, the metal wire 14 is inserted into the dielectric tube 13, and the dielectric tube 13 is connected to the dielectric 3 of the voltage applying electrode 2 and the porous film 15. By applying a high frequency / high voltage in the contact state, it is possible to form a strong electric field field in which the electric field is concentrated.

The device shown in FIG. 3 is different from the device having the structure shown in FIG. 2 in that the dielectric tube 13a is buried in the dielectric 3 and the metal tube 14b is inserted into the dielectric tube 13b. It is also a configuration provided in. This metal wire 1
4b is electrically connected to the ground electrode 5, and the metal wire 14a is electrically connected to the voltage applying electrode 2. Also, as in the previous embodiment,
The diameters of the dielectric tubes 13a and 13b are metal wires 14a and 14b.
Is larger than the diameter of the porous film 1
When 5 is conveyed, these metal wires 14a and 14b do not rotate, but the dielectric tubes 13a and 13b rotate in mutually opposite directions. In this embodiment, since the dielectric tube 13b is also provided on the ground electrode 5, it is possible to form a stronger electric field field as compared with the previous embodiments.

Further, as shown in FIG. 4, a dielectric 3c in which the above-mentioned dielectric tube 13c is embedded is provided around the ground electrode 5. In this device, the dielectric tubes 13a and 13c are rotatable, and the porous film 15 is installed in a state of being sandwiched between these dielectric tubes 13a and 13c. Are rotated in opposite directions and are sequentially conveyed.

The embodiment shown in FIG. 4 has a structure in which a plurality of dielectric tubes are provided. However, as shown in FIG. 5, a structure in which one dielectric tube is provided inside each of the dielectrics 3a and 3c is provided. Good.

[0037]

As described above, according to the method of the present invention, since a high frequency / high voltage is applied to the application electrode under a high pressure equal to or higher than the atmospheric pressure, a strong electric field is formed. Therefore, the plasma region can be concentrated. Therefore, high-density plasma can be generated on the surface of the porous body and in the spaces inside the pores, and the modification treatment of the porous body can be performed easily and uniformly. Further, when the dielectric is fixed to both electrodes or one of the electrodes, it is possible to prevent the occurrence of arc discharge when a voltage is applied, and it is possible to maintain stable plasma.

In the apparatus for treating a porous body of the present invention, since a high frequency / high voltage is applied to the applying electrode under the high pressure equal to or higher than the atmospheric pressure and the adjusting means is provided, High-density plasma can be generated on the surface and in the space inside the pores, making it easy to modify the porous body.
Moreover, it is performed uniformly. Further, the distance between both electrodes can be adjusted according to the thickness of the porous body, and an appropriate distance can be set for each treatment. Further, if both electrodes are adjusted so as to be in contact with the porous body, the distance between both electrodes becomes shorter and a strong electric field can be formed. Further, since the feeding means and the winding means are provided, the sheet-shaped porous body can be continuously modified and the processing capacity can be increased.

[Brief description of drawings]

FIG. 1 is a diagram schematically showing an embodiment of the device of the present invention.

FIG. 2 is a diagram schematically showing another embodiment of the device of the present invention.

FIG. 3 is a diagram schematically showing still another embodiment of the device of the present invention.

FIG. 4 is a diagram schematically showing still another embodiment of the device of the present invention.

FIG. 5 is a diagram schematically showing still another embodiment of the device of the present invention.

[Explanation of symbols]

1 ... Reaction gas inlet 2 ... Voltage application electrode 3 ... Dielectric 4 ... Porous body 5 ... Ground electrode 6 ... Elevating platform 8 ... High-frequency power supply 10 ... Processing chamber 11 ... Feeding roll 12 ... Winding roll

─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Masakatsu Urairi, 1-2, Shimohozumi, Ibaraki City, Osaka Prefecture Nitto Denko Co., Ltd. (56) Reference JP-A-8-57225 (JP, A) Kaihei 8-337676 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) C08J 9 / 36,7 / 00 B29C 71/04

Claims (5)

(57) [Claims] 1. A voltage applying electrode for applying a voltage and a ground electrode are arranged in a chamber with a porous body having a plurality of holes inside interposed between the electrodes.
In the method for treating the porous body by introducing a reaction gas into the chamber and applying a voltage to the voltage applying electrode to generate plasma, the chamber is set to have an atmospheric pressure or higher and the voltage applying electrode is A method for modifying a porous body, characterized in that high-density plasma is generated on the surface of the porous body and in the inner spaces of the pores by applying a high frequency / high voltage. 2. The method for modifying a porous body according to claim 1, wherein a dielectric is fixed to both electrodes or one of the electrodes. 3. A chamber, a reaction gas introducing means for introducing a reaction gas into the chamber, and a voltage applying electrode and a ground electrode which are arranged to face each other in the chamber,
By introducing a reaction gas with a porous body interposed between both electrodes and applying a voltage to the voltage applying electrode,
In the apparatus for processing the porous body, the inside of the chamber is set to an atmosphere of atmospheric pressure or higher, a high frequency / high voltage is applied to the voltage applying electrode, and the distance between the electrodes is adjusted. A reforming apparatus for a porous body, characterized in that it is provided with an adjusting means. 4. A feeding means for feeding a sheet-shaped porous body while moving between the two electrodes in a predetermined direction, and a winding means for winding up the fed porous body. The modification treatment apparatus for a porous body according to claim 3. 5. The modification treatment apparatus for a porous body according to claim 3, wherein a dielectric is fixed to both of the electrodes or one of the electrodes.