JP2010029831A - Plasma treatment method for powder - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a plasma treatment method for a powder capable of imparting a nitrogen functional group of high concentration to the powder under a stable glow discharge environment. <P>SOLUTION: The plasma treatment method for the powder uses a discharge container 1 having a central electrode 2, a cylindrical peripheral electrode 3 arranged through a predetermined gap 5 with respect to the central electrode 2 and a dielectric 4 provided to at least one of the surface of the central electrode 2 and the surface of the peripheral electrode 3 and includes a process for applying plasma treatment by glow discharge to a powder and a nitrogen functional group supply member for adding the nitrogen functional group to the powder in the gap 5 set to an inert gas atmosphere. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a powder plasma processing method. More specifically, the present invention relates to a powder plasma processing method for performing surface modification of powder using glow discharge plasma under atmospheric pressure.

Attempts have been made to improve the hydrophilicity or hydrophobicity by adding nitrogen functional groups that react with various functional groups to the surface of the powder using plasma treatment. A reforming technique using treatment is disclosed. Specifically, as shown in FIG. 5, first, an inert gas helium gas is put into the gas storage tank 102 from the cylinder 101, and then the helium gas is passed through the acetone of the vaporizer 103 as a bubble, and the helium gas Acetone vapor is mixed therein to produce a mixed gas, and the mixed gas thus produced is introduced into the reaction tube 105 by the pump 104.
Here, plasma discharge is started in the reaction tube 105 by applying a high-frequency high voltage from the high-voltage power source 106, and then a hopper 107 containing the powder is opened to put a certain amount of powder into the reaction tube 105. A method is disclosed in which surface modification of a powder is performed by suction and passing through a plasma excited while stirring the powder by the pressure of a mixed gas.

Japanese Patent Laid-Open No. 4-135638

  Here, the invention in Patent Document 1 is a method of performing a plasma treatment while stirring powder by an air flow of a mixed gas, and a mixed gas obtained by mixing an inert gas such as helium gas and a ketone such as acetone is used. Equipment to make is required. However, since the processing amount of the powder to be processed in the reaction cylinder is limited, it is difficult to say that the processing efficiency is sufficient for the equipment.

  In addition, nitrogen functional groups can be added using a mixed gas of helium gas and ammonia gas or helium gas and nitrogen gas, and by increasing the blending ratio of nitrogen gas or ammonia gas, many nitrogen functional groups can be added. It is known that it can be granted. However, when the blending ratio of nitrogen gas or ammonia gas is increased, abnormal discharge is likely to occur and it is difficult to maintain stable glow discharge.

  The present invention was devised in view of the above points, and an object of the present invention is to provide a plasma treatment method for powder that can impart a high concentration of nitrogen functional groups in a stable glow discharge environment. To do.

  In order to achieve the above object, a plasma treatment method for powder according to the present invention comprises a center electrode, a cylindrical peripheral electrode disposed via the center electrode and a predetermined gap, and the surface of the center electrode or the periphery. A powder plasma processing method using a discharge vessel having a dielectric provided on at least one of electrode surfaces, wherein the powder and a nitrogen functional group are contained in the powder in a void formed in an inert gas atmosphere. A step of performing plasma treatment by glow discharge on the nitrogen functional group supply member to which is added.

  Here, a high concentration of functional groups is formed by plasma treatment that encloses a substance serving as a nitrogen functional group supply source together with the powder in the gap between the central electrode and the peripheral electrodes and generates between the central electrode and the peripheral electrodes. It can be added to the powder.

  In addition, the plasma treatment is performed while rotating the discharge vessel around the center electrode, with an alternating current or pulse voltage applied between the center electrode and the peripheral electrode. The substance serving as the nitrogen functional group supply source can add a uniform and high concentration functional group to the powder by the plasma discharge generated between the central electrode and the peripheral electrode while being stirred.

  In addition, the powder is always introduced into the gap of the discharge vessel, and the inert gas is supplied from one end of the discharge vessel into the gap and is discharged from the other end of the discharge vessel, so that the atmospheric pressure is always maintained. The powder is uniformly agitated by the supply of the inert gas below, so that the surface treatment of the powder under favorable conditions becomes possible.

  Further, the nitrogen functional group supply member has a nitrogen functional group and is formed of a solid compound at room temperature, for example, aliphatic nylon serving as a nitrogen functional group supply source, a copolymer containing aliphatic nylon, By forming it with either aromatic nylon, a copolymer containing aromatic nylon, or urea, high concentration can be efficiently achieved under stable glow discharge without increasing the amount of nitrogen gas above a certain amount. Nitrogen functional groups can be added to the powder.

  In addition, when the inert gas is formed of helium, argon, neon, nitrogen gas, or a mixture thereof, for example, a high concentration nitrogen functional group is formed by a mixed gas of helium and nitrogen gas or ammonia gas. The group can be added to the powder, and even in the case of helium alone, the nitrogen functional group can be added to the powder.

  The center electrode is provided with a first protrusion protruding in the direction of the peripheral electrode, the peripheral electrode is provided with a second protrusion protruding in the direction of the center electrode, or the center electrode protrudes in the direction of the peripheral electrode. The first convex portion to be provided and the second convex portion protruding in the direction of the center electrode on the peripheral electrode are provided, whereby the powder sealed in the gap portion and the nitrogen functional group supply source are provided. The resulting material can be efficiently agitated by the first convex portion or the second convex portion, thereby enabling uniform surface treatment by plasma discharge.

  In addition, by providing a partition provided continuously with the center electrode and the peripheral electrode, a powder and a substance serving as a nitrogen functional group supply source are sealed in a space formed between each partition. This makes it possible to increase the amount of powder processed by plasma discharge.

  According to the plasma treatment method of the powder of the present invention, by enclosing a substance serving as a nitrogen functional group supply source together with the powder in the gap between the central electrode and the peripheral electrode of the discharge vessel, It becomes possible to add a high concentration of functional groups to the powder.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a front sectional view showing an example of a discharge vessel in a plasma processing apparatus used for carrying out a powder plasma processing method to which the present invention is applied, and FIG. 2 is a powder plasma processing method to which the present invention is applied. It is side surface sectional drawing which shows an example of the discharge vessel in the plasma processing apparatus used in order to do.

  The discharge vessel 1 shown here is in close contact with a central electrode 2 formed of electrodes, a peripheral electrode 3 coaxial with the central electrode 2, and an outer peripheral surface of the central electrode 2 and an inner peripheral surface of the peripheral electrode 3. It is comprised from the dielectric 4 and the space | gap part 5 formed between this dielectric 4 by this.

  The dielectric 4 is made of an insulating material such as glass, and is formed between the dielectric 4 fitted on the outer peripheral surface of the center electrode and the dielectric 4 fitted on the inner week surface of the peripheral electrode. The gap 5 is configured such that the capacity of the gap 5 can be increased by increasing the diameter or total length of the center electrode 2 and the peripheral electrode 3 while maintaining a certain distance necessary for plasma discharge.

  Next, a convex portion 6 is projected on the inner peripheral surface of the dielectric 4 of the peripheral electrode 3 toward the gap portion 5 in the direction of the central electrode 2, and this convex portion 6 is an insulating material having heat resistance such as glass or ceramics. It is formed of an insulating member such as nylon as a member or a nitrogen functional group supply source, and the powder filled in the gap 5 can be stirred by the convex portion 6 by rotating the discharge vessel 1. It is said that.

  In addition, a gas injection tube 7 is attached to the open end of the gap portion 5 on one end side of the discharge vessel 1, and this gas injection tube 7 is attached in a state of penetrating through a sealing film portion 8 formed of silicon rubber. Yes.

  In addition, a sealing film portion 8 made of silicon rubber is attached to the other end of the gap portion 5 of the discharge vessel 1, and a gas discharge hole 9 is opened in the sealing film portion 8. A filter 10 that allows only the light to pass therethrough is provided.

  Here, as shown in FIG. 3, the discharge vessel 1 is rotated by a tabletop pot mill rotating table 11, and this tabletop pot mill rotating table 11 is driven to rotate in the same direction by an electric motor (not shown). A configuration in which the discharge vessel 1 is placed between two drive rotators 11 so as to be parallel to the axis of the vessel 1 and the discharge vessel 1 is rotated by rotating any one of the drive rotators 14; Has been.

  A gas hose that injects a mixed gas into the gas injection tube 7 of the discharge vessel 1 by bringing the brush electrode terminals 12 to which a high-frequency power source (not shown) is applied into contact with the center electrode 2 and the peripheral electrode 3 of the discharge vessel 1. 13 is configured to be able to inject the mixed gas while rotating the discharge vessel 1 via a bearing or the like.

Here, examples of the surface treatment of the polypropylene polymer powder by the plasma treatment method of the powder to which the present invention is applied using the plasma treatment apparatus described above will be shown.
Example 1
Polypropylene polymer powder (Nippon Polypro Co., Ltd.) is placed in the gap between the dielectrics with one blade formed from Nomex (a 0.7 mm thick insulating paper made of aromatic nylon copolymer, manufactured by DuPont). ), NOVATEC P-8000, average particle size 300 micrometers) 12 g and nylon chip (MC102 manufactured by Kanebo) 2 g are charged and placed on a tabletop pot mill rotary table (AZN-51S manufactured by Nippon Ceramics Co., Ltd.). It was rotated within a rotational speed range of ˜8 rpm.

  Further, a mixed gas of helium 4.5 l / min and nitrogen 0.45 l / min is introduced into the gap of the discharge vessel, and after flowing for 1 minute, a high frequency power source (AGF manufactured by Kasuga Electric Co., Ltd.) −012), a sine wave voltage of 36 kHz was applied, and a plasma treatment was performed at a plasma output of 200 W for 5 minutes.

  After the plasma treatment, the polypropylene polymer powder and the nylon tip were taken out from the discharge vessel, and the nylon tip was removed with a sieve.

Example 2
Next, the sample filling is the same as in Example 1, and 12 g of polypropylene polymer powder and 2 g of nylon chip are charged, placed on a tabletop pot mill rotary table and rotated within a rotation speed range of 5 to 8 rpm, as plasma gas. Without adding nitrogen, only 4.5 l / min of helium was introduced into the gap of the discharge vessel, and after flowing for 1 minute, a sine wave voltage of 36 kHz was applied with a high frequency power source while flowing the mixed gas as it was, After performing plasma treatment at an output of 200 W for 5 minutes, the polypropylene polymer powder and the nylon chip were taken out from the discharge vessel, and the nylon chip was removed with a sieve.

Example 3
Into the gap of the discharge vessel in Example 1, 2 g of polypropylene polymer powder 12 g and Teijin Co., Ltd. aromatic fiber copolymer fiber techno cut into length of about 2 cm were added, and the tabletop pot mill rotary table The mixture is rotated within a rotation speed range of 5 to 8 rpm, a mixed gas of helium 4.5 l / min and nitrogen 0.45 l / min is introduced into the gap of the discharge vessel, and after flowing for 1 minute, it is mixed as it is. A 36 kHz sine wave voltage is applied with a high frequency power supply while flowing gas, and after a plasma treatment is performed at a plasma output of 200 W for 5 minutes, the polypropylene polymer powder and technola fiber are taken out from the discharge vessel, and the technola fiber is removed with a sieve did.

Example 4
Nylon with a thickness of 5 mm is used as the dielectric of the discharge vessel in Example 1, 15 g of polypropylene polymer powder is put into the gap, and it is placed on a tabletop pot mill rotary table and rotated within a rotation speed range of 5 to 8 rpm. Without adding nitrogen as a plasma gas, only 4.5 l / min of helium is introduced into the gap of the discharge vessel, and after flowing for 1 minute, a 36 kHz sine wave voltage is supplied by a high frequency power source while flowing the mixed gas as it is. And plasma treatment was performed at a plasma output of 200 W for 5 minutes.

Comparative Example 1
Only 15 g of the polypropylene polymer powder was put into the gap of the discharge vessel in Example 1, placed on a tabletop pot mill rotary table, rotated within a rotation speed range of 5 to 8 rpm, helium 4.5 l / min, nitrogen 0 .45 l / min of mixed gas is introduced into the gap of the discharge vessel, and after flowing for 1 minute, a 36 kHz sine wave voltage is applied with a high frequency power source while flowing the mixed gas as it is, and plasma is output at a plasma output of 200 W for 5 minutes. Processed.

The polypropylene powder plasma-treated in Examples 1 to 5 and Comparative Example 1 was measured for a photoelectron spectrum with an X-ray photoelectron spectrometer (XPS) (Shimadzu Kratos AXIS-165), and N _1S peak and The results of calculating the N / C atomic ratio from the area of the C _1S peak are shown in Table 1 below.

  From the above results, as in Example 1, Example 3 and Example 4, together with polypropylene polymer powder, a nitrogen group supply source such as nylon chip or techno fiber was introduced, and a mixed gas of helium gas and nitrogen gas was introduced. Plasma treatment, an atomic ratio of 0.20 or more can be obtained, and a significant addition of nitrogen functional groups compared to the atomic ratio of 0.14 in the case of only polypropylene polymer powder as in Comparative Example 1 is achieved. It turned out to be possible.

  Further, in Example 2, it was found that a nylon chip was introduced together with polypropylene polymer powder, and that an atomic ratio of 0.1 was obtained by plasma treatment while introducing only helium gas. It was confirmed that the group could be added.

  Furthermore, in Example 5, it was found that nylon was used as the dielectric, only polypropylene polymer powder was added, and an atomic ratio of 0.043 was obtained by plasma treatment while introducing only helium gas. It was confirmed that addition of a nitrogen functional group was possible without nitrogen gas.

Next, FIG. 4 is a front sectional view showing another example of the discharge vessel in the plasma processing apparatus used for carrying out the powder plasma processing method to which the present invention is applied.
In another example shown here, a partition 16 for partitioning the gap 5 formed between the center electrode 1 and the peripheral electrode 3 of the discharge vessel 1 is provided between the dielectrics 4. The partition 16 is formed of a heat-resistant insulating material such as glass, ceramics, or nylon. For example, the gap 5 is divided into two rooms by two partitions 16 (see FIG. 4A). Alternatively, the gap 5 is divided into three rooms by three partitions 16 (see FIG. 4 (B)), and a substance that serves as a powder and nitrogen functional group supply source and an inert gas can be introduced into each room. It is configured.

  Further, by dividing the inside of the gap portion 5 into a plurality of rooms by the partitioning portion 16, the nitrogen group supply source such as the polypropylene polymer powder and the nylon chip or the technola fiber implemented in the first to fifth embodiments is provided in each room. By adding it, it becomes possible to increase the plasma treatment amount of the polypropylene polymer powder.

  Note that it is not always necessary to perform plasma processing of the powder by the plasma processing apparatus described in detail in this embodiment. For example, a powder and a substance serving as a nitrogen functional group supply source such as blow-up plasma processing are added together. Any apparatus that can stir may be used.

  The nitrogen functional group supply source may be insulative solid and may be in the form of powder, fiber, film, chip, etc., and its chemical structure contains nitrogen functional groups such as amino groups and imino groups. For example, various amines, amides, amino acids, urea, melamine, nylon and copolymers thereof may be used.

  Further, the dielectric used in the discharge vessel, or the convex portion and the partitioning portion can be formed of a material which is a nitrogen functional group supply source.

It is front sectional drawing which shows an example of the discharge vessel in the plasma processing apparatus used in order to implement the plasma processing method of the powder to which this invention is applied. It is side surface sectional drawing which shows an example of the discharge vessel in the plasma processing apparatus used in order to implement the plasma processing method of the powder to which this invention is applied. It is explanatory drawing which shows an example of the plasma processing apparatus used in order to implement the plasma processing method of the powder to which this invention is applied. It is front sectional drawing which shows the other example of the discharge vessel in the plasma processing apparatus used in order to implement the plasma processing method of the powder to which this invention is applied. It is explanatory drawing which shows an example of the conventional powder surface treatment method.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Discharge vessel 2 Center electrode 3 Peripheral electrode 4 Dielectric 5 Gap part 6 Protrusion part 7 Gas injection pipe 8 Sealed film part 9 Gas discharge hole 10 Filter 11 Tabletop pot mill rotary table 12 Brush electrode terminal 13 Gas hose 14 Drive rotary body 16 Partition Part

Claims (8)

A discharge vessel having a central electrode, a cylindrical peripheral electrode disposed through the central electrode and a predetermined gap, and a dielectric provided on at least one of the surface of the central electrode or the surface of the peripheral electrode is used. A method for plasma processing of powder,
A powder plasma processing method comprising a step of performing plasma treatment by glow discharge on a powder and a nitrogen functional group supply member for adding a nitrogen functional group to the powder in the void portion in an inert gas atmosphere. 2. The plasma processing method according to claim 1, wherein the plasma processing is performed while rotating the discharge vessel with the center electrode as a rotation center in a state where an alternating current or a pulse voltage is applied between the center electrode and the peripheral electrode. . The powder is charged into the gap of the discharge vessel, and the inert gas is supplied into the gap from one end of the discharge vessel and discharged from the other end of the discharge vessel. The plasma processing method according to claim 1 or 2. The plasma processing method according to claim 1, wherein the nitrogen functional group supply member has a nitrogen functional group and is formed of a solid compound at room temperature. 5. The plasma processing method according to claim 1, wherein the inert gas is formed by helium, argon, neon, nitrogen gas, or a mixture thereof. The central electrode is provided with a first convex portion protruding in the direction of the peripheral electrode,
Or
The peripheral electrode is provided with a second convex portion protruding in the direction of the central electrode,
Or
The plasma processing method according to claim 1, wherein the center electrode is provided with a first protrusion protruding in the direction of the peripheral electrode, and the peripheral electrode is provided with a second protrusion protruding in the direction of the center electrode. . The plasma processing method according to claim 1, further comprising a partition portion that is connected to the center electrode and the peripheral electrode. A powder plasma processing method comprising: a step of performing a plasma treatment by glow discharge in an inert gas atmosphere on a powder and a nitrogen functional group supply member for adding a nitrogen functional group to the powder.

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