JP3691933B2 - Method of processing inner surface of container body or cylindrical body using plasma - Google Patents

Description

【００３１】
この回路の利点は、負荷のインピーダンスが高い場合であっても、充電されている電荷をＳＷ２とＤ４又はＳＷ４とＤ２を動作させることによって確実に放電することができる点、及び、高速ターンオンのスイッチ素子であるＳＷ１、ＳＷ３を使って高速に充電を行うことができる点にあり、このため、図２のように立ち上がり時間、立ち下がり時間の非常に早いパルス信号を得ることができる。
【００３２】
本発明の方法によって、内面処理される容器体もしくは筒状体の形状としては、中空の通常の立体容器体もしくは筒状体で、少なくとも１個の開口部を有する形状であることが好ましく、例えば、瓶、試験管、注射器外筒、プラスチックコップ等のように一方が開口している容器体、ホース、チューブのように両側が開口している筒状体、ブロー成形したガソリンタンク、三口フラスコ、医療用輸液容器等の複数の開口部を有する容器体もしくは筒状体が挙げられる。
【００３３】
又、上記容器体もしくは筒状体の材質としては、特に限定されるものではなく、通常のプラスチック、エンジニアリングプラスチック、無機物等が挙げられ、例えば、ポリエチレン、ポリプロピレン、ポリスチレン、ポリカーボネート、ポリエチレンテレフタレート、ポリフェニレンサルファイト、ポリテトラフルオロエチレン、アクリル樹脂等のプラスチック、ほうけい酸ガラス、ソーダガラス、石英ガラスなどのガラス類、アルミナ、ジルコニア等のセラミック類、アルミニウム、銅、ステンレス等の金属類等の無機物が挙げられる。
【００３４】
本発明の処理される上記容器体もしくは筒状体の肉厚は、０．０５〜４ｍｍであることが好ましく、肉厚が４ｍｍを超えると、放電プラズマを発生させるのに高電圧を要し、０．０５ｍｍ未満の場合は、電圧印加の時に、絶縁破壊が起こり、アーク放電が起こる場合が多い。
【００３５】
本発明の容器体もしくは筒状体内面処理に於いては、容器体もしくは筒状体内部の放電プラズマ発生空間に存在する気体（以下、処理用気体という）の選択によって、各種の機能を容器体もしくは筒状体の内面に付与することができる。
【００３６】
上記処理用気体として、フッ素含有化合物ガスを用いると、容器体もしくは筒状体内面にフッ素含有基を形成させて、表面エネルギーを低くし、撥水性の表面にすることができる。
【００３７】
フッ素含有化合物としては、例えば、４フッ化炭素（ＣＦ₄ ）、６フッ化炭素（Ｃ₂ Ｆ₆ ）、６フッ化プロピレン（ＣＦ₃ ＣＦＣＦ₂ ）、８フッ化シクロブタン（Ｃ₄ Ｆ₈ ）等のフッ素−炭素化合物、１塩化３フッ化炭素（ＣＣｌＦ₃ ）等のハロゲン−炭素化合物、６フッ化硫黄（ＳＦ₆ ）等のフッ素−硫黄化合物等が挙げられる。
安全上の観点から、有害ガスであるフッ化水素を生成しない４フッ化炭素、６フッ化炭素、６フッ化プロピレン、８フッ化シクロブタンを用いることが好ましい。
【００３８】
又、処理用ガスとして、酸素含有化合物、窒素含有化合物、硫黄含有化合物、酸素、酸素と水素との混合気体、オゾン、水蒸気、酸素と有機化合物との混合気体を使用して、容器体もしくは筒状体内面に、カルボキシル基、カルボニル基、水酸基、アミノ基等の親水基を形成させて、表面エネルギーを高くして、内面を親水性にすることができる。
【００３９】
酸素含有化合物としては、例えば、酸素、オゾン、水、一酸化炭素、二酸化炭素、一酸化窒素、二酸化窒素の他、メタノール、エタノール等のアルコール類、アセトン、メチルエチルケトン等のケトン類、メタナール、エタナール等のアルデヒド類等の酸素を含有する有機化合物等が挙げられ、これらの少なくとも１種が使用できる。
更に、酸素含有化合物とメタン、エタン等の炭化水素化合物のガスとを混合して用いてもよい。
又、酸素含有化合物に５０体積％以下でフッ素含有化合物を添加することにより親水性が促進される。
フッ素含有化合物としては、上記例示と同様のものを用いればよい。
【００４０】
窒素含有化合物としては、例えば、窒素、アンモニア等が挙げられ、窒素含有化合物と水素を混合して用いてもよい。
【００４１】
硫黄含有化合物としては、例えば、二酸化硫黄、三酸化硫黄、硫酸の気化体が挙げられ、これらの単独、又は、２種以上を混合して用いてもよい。
【００４２】
又、分子内に親水性基と重合性不飽和結合を有するモノマーの雰囲気下で処理することにより、親水性の高分子膜を積層させることもできる。
親水性基としては、水酸基、スルホン酸基、スルホン酸塩基、１級、２級、３級アミノ基、アミド基、４級アンモニウム塩基、カルボキシル基、カルボン酸塩基等の親水基が挙げられる。
又、ポリエチレングリコール鎖を有するモノマーを用いても同様に親水性の高分子膜を積層させることができる。
【００４３】
上記モノマーとしては、例えば、アクリル酸、メタクリル酸、アクリルアミド、メタクリルアミド、Ｎ，Ｎ−ジメチルアクリルアミド、アクリル酸ナトリウム、メタクリル酸ナトリウム、アクリル酸カリウム、メタクリル酸カリウム、スチレンスルホン酸ナトリウム、アリルアルコール、アリルアミン、ポリエチレングリコールジメタクリル酸エステル、ポリエチレングリコールジアクリル酸エステル等が挙げられ、これらの少なくとも１種が使用できる。
【００４４】
更に、Ｓｉ、Ｔｉ、Ｓｎ等の金属の金属−水素化合物、金属−ハロゲン化合物、金属アルコラート等の処理用ガスを用いて、ＳｉＯ₂ 、ＴｉＯ₂ 、ＳｎＯ₂ 等の金属酸化物薄膜を形成させ、容器体もしくは筒状体内面に電気的、光学的機能を与えることができる。
【００４５】
経済性、安全性の観点から、容器体もしくは筒状体内部に供給する処理用気体は、以下の希釈ガスで希釈した気体組成物を使用することが好ましい。
希釈ガスとしては、ヘリウム、ネオン、アルゴン、キセノン等の希ガス、窒素気体等が挙げられ、これらの少なくとも１種が使用できる。
本発明の方法に於いては、希釈ガスとして、アルゴン及び／又は窒素を採用することが好ましい。
従来より大気圧近傍の圧力下に於いては、ヘリウムの存在下での表面処理が行われてきたが、アルゴンと窒素は、ヘリウムに比較して安価な気体であり、又、ヘリウムより大きな分子量をもつため高密度プラズマ状態を安定して実現できるので、工業生産の上で、大きな優位性が発揮できる。
【００４６】
【発明の実施の形態】
図６、図７に、本発明の表面処理を行う装置の一例を示す。
これらの装置は、主として、交流電源（高電圧パルス電源）１、処理用気体導入管２、電極３、４、被処理体である容器体もしくは筒状体５、容器体もしくは筒状体の支持体６、処理用気体排出管７から構成される。
上記の電極３、４は、必要に応じて、両者が対向する面の上に少なくとも一方の全面に固体誘電体（図に記載されていない）が設置されていても構わない。
【００４７】
図６の容器体（試験管）の内面処理の例に於いて、内面が処理される容器体５は、電極３、４が直接対向しないように、両電極の間に設置されている。
容器体５の開口部は、支持体６によって電極３、４の端部の位置で正確に固定され、処理用気体の導入管２が支持体６を貫通して設置される。
支持体６は、容器体を保持する為と処理気体に他の外気が侵入するのを抑える役割があるが、容器体の内部を完全に密封するものではない。
【００４８】
処理用気体は、処理用気体供給タンク、流量調節装置（両者とも、図に記載されていない）を通って、処理用気体導入管２から、容器体５の内部が一定の圧力の陽圧になるように供給される。余分の気体は、容器体５の開口部と支持体６から少量ずつ排出される。
しかる後に、電極３、４に所定のパルス電界が印加され、容器体の内部に放電プラズマが発生し、プラズマが接触している領域が表面処理される。
【００４９】
図７は、筒状体の例であって、筒状体の両端が支持体６で保持され、処理用気体導入管２と処理用気体排出管７が接続されている。処理方法は、図６の容器体と基本的に同じである。
【００５０】
上記表面処理を行う装置の材質は、樹脂、ガラス等が挙げられるが、特に限定されない。電極と絶縁が取れる構造になっていれば、ステンレス、アルミニウム等の金属を用いることもできる。
【００５１】
本発明の内面処理は、容器体もしくは筒状体を加熱、又は、冷却して行ってもよいが、室温下で充分である。
上記の表面処理に要する時間は、印加電圧、処理用気体の種類、及び、混合気体組成等を考慮して、適宜、決定される。
【００５２】
本発明の容器体もしくは筒状体内面の処理方法を、更に理解し易くするために、実施例をもって、以下に説明する。
実施例１
図６に示した装置に於いて、電極３と電極４に銅板（１００×２０ｍｍ、肉厚を２０ｍｍ）を用い、容器体５は、ポリエチレンテレフタレート製の採血管（積水化学社製、真空採血管インセパック−Ｎ、外径：１５ｍｍ、全高：１００ｍｍ）を使用した。
上記の採血管を、図６に示すように、電極３と電極４との間に挟むように配置したが、電極間距離は１５ｍｍで、採血管の外径が１５ｍｍであったから、事実上、採血管を電極に嵌込む状態であった。
【００５３】
しかる後に、気体導入管２を通じて、窒素ガス２０００ｓｃｃｍを採血管内部に導入しながら、電極３と電極４との間に周波数８ｋＨｚ、波高値６ｋＶのパルス電界（ピーク−ピーク値１２ｋＶ）の印加を５秒間行った。
採血管内部にプラズマによる均一な発光が観察された。
尚、印加したパルス電界の電圧波形図を図８に示した。
【００５４】
処理後の採血管について、未処理の採血管と共に、下記に示す測定方法に従って、接触角の測定と血餅付着状況の評価を行った。
＜接触角評価＞
処理後の採血管の内壁面に水滴２μｌを滴下し、接触角測定装置（協和界面科学社製、商品名：ＣＡ−Ｄ）を用いて、静的接触角を測定した。
未処理の採血管が、６５度であるのに対し、処理した採血管は、１０度であり、親水化されていることが確認できた。
【００５５】
＜血餅付着状況の評価＞
うさぎの新鮮な血液を、４〜５ｍｌ／本の割合で採血して、室温にて放置し、完全に凝固した後に３０００ｒｐｍで、５分間、遠心分離した。
その後、血清の分離状況と内壁面への血餅成分の付着状況を目視で観察した。
結果は、未処理品に比べて、処理品では良好な血清分離状態を示し、血餅成分の付着も遙に少なかった。
【００５６】
【発明の効果】
本発明の容器体もしくは筒状体内面の処理方法は、上述のように構成されているので、処理の際のガス雰囲気の種類を問わず、大気圧近傍の圧力下で実施でき、被処理体である容器体もしくは筒状体自身が、チャンバーの働きをするので、従来のようにプラズマを発生させる空間のチャンバーを必要としない。
従って、プラズマ処理装置が簡便化され、消費される気体の量も従来の方法より遙に少なくて済む。
【００５７】
【図面の簡単な説明】
【図１】 パルス化された電界の例を示す電圧波形図である。
【図２】 １つのパルス電界の形成時間の説明図である。
【図３】 パルス化された電界を発生させる電源のブロック図である。
【図４】 パルス化された電界を発生させる電源の等価回路図である。
【図５】 パルス化された電界の動作表に対応する出力パルス信号の図である。
【図６】 本発明の放電プラズマ処理装置の一例である。
【図７】 本発明の放電プラズマ処理装置の他の例である。
【図８】 実施例１に使用したパルス電界の波形である。
【符号の説明】
１ パルス電源
２ 気体導入管
３、４ 電極
５ 被処理体である容器体もしくは筒状体
６ 支持体
７ 処理用気体排出管[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for treating an inner surface of a container body or a cylindrical body with a discharge plasma under a pressure near atmospheric pressure.
[0002]
[Prior art]
Conventionally, various surface treatment methods for hydrophilizing or hydrophobizing the inner surface of a molded body such as a plastic bottle or a glass container have been proposed, but these are mainly silane coupling agents or silicon. A method of coating the surface with a solution has been taken, but this method has a cost increase due to drying of the solvent and a defect that dust adheres to the processing process, which leads to fatal damage to food and medical containers There were many things.
[0003]
As a method for eliminating the above-described defects, for example, in Japanese Patent Laid-Open No. 5-269370, as a dry processing method that does not use a solution, a molded body to be processed is disposed between opposing electrodes, and the molded body A method of surface-treating the inner surface of the molded body is disclosed by exciting the gas with plasma and bringing the gas into contact with the inner surface of the molded body.
[0004]
However, in the above method, the gas introduced into the molded body is a gas composition containing helium or ketones, and is performed in a specified gas atmosphere.
For this reason, helium gas is expensive, and ketones often react on the treated surface or become impurities to contaminate the product itself, which is an industrially disadvantageous method in terms of cost and quality.
[0005]
[Problems to be solved by the invention]
The present invention solves the above-described problems, generates a uniform and stable discharge plasma under a pressure near atmospheric pressure, regardless of the type of gas atmosphere during the inner surface treatment, and Alternatively, an object is to provide a method for plasma-treating the inner surface of a cylindrical body.
[0006]
[Means for Solving the Problems]
The processing method for the inner surface of a container body or a cylindrical body using plasma according to the present invention is a container body or a cylindrical body in which a processing gas is supplied between opposing electrodes under a pressure near atmospheric pressure. And a discharge plasma is generated by applying a pulsed electric field between the electrodes.
[0007]
Under pressures near atmospheric pressure, it is known that the plasma discharge state is not stably maintained except for the above-mentioned specific gases such as helium and ketone, and the state is instantaneously shifted to the arc discharge state. By applying an electric field, it is considered that a cycle of stopping the discharge before starting the arc discharge and starting the discharge again is realized.
[0008]
Under a pressure close to atmospheric pressure, the method of applying a pulsed electric field of the present invention is the first time in an atmosphere that does not contain a component that takes a long time from a plasma discharge state such as helium or ketone to an arc discharge state. It is possible to stably generate discharge plasma.
[0009]
According to the method of the present invention, discharge plasma can be generated in the air. Known plasma processing under low-pressure conditions requires that processing be performed in a sealed container that is shielded from outside air, even in plasma processing under atmospheric pressure conditions containing a specific gas. However, a complicated process such as using a large sealed container in which the body or the cylindrical body itself is contained, or filling and sealing the container body or the cylindrical body with gas is required. However, the container body or the cylindrical body of the present invention According to the surface processing method, after filling the container body or the cylindrical body with a gas, a simple partition that prevents the free outflow of the gas may be provided, which is very advantageous in terms of the process.
[0010]
Further, according to the method of applying a pulsed electric field, a high-density plasma state can be realized, which is very significant in performing industrial processes such as continuous processing.
[0011]
The pressure under the atmospheric pressure refers to a pressure of 100 to 800 Torr. A range of 700 to 780 Torr is preferable because pressure adjustment is easy and the apparatus is simple.
[0012]
In the method for treating an inner surface of a container body or a cylindrical body of the present invention, a container body to be treated is disposed between opposing electrodes. At this time, it is preferable to arrange the container body so that the electrodes do not directly face each other.
If there is a part where both electrodes are directly opposed without interposing a container body or a cylindrical body, arc discharge occurs in that part, the current density flowing becomes uneven, and uniform processing becomes difficult.
[0013]
When the container body or cylindrical body to be treated is arranged so that the electrodes do not directly face each other, that is, in a form that completely covers both electrode surfaces, high voltage is not required, and it is effective and economical. Can be internally treated.
When it is desired to completely avoid non-uniform processing, it is preferable that a solid dielectric is provided on at least one of the opposing surfaces of the electrode.
[0014]
The part where plasma is generated occurs in the space between both electrodes, including the space inside the container body or cylindrical body. When a solid dielectric is placed on one of the electrodes, the electrode between the solid dielectric and the electrode When a solid dielectric is installed on both sides, it is a space between the solid dielectrics.
[0015]
Examples of the electrode include those made of simple metals such as copper and aluminum, alloys such as stainless steel and brass, and intermetallic compounds.
The counter electrode preferably has a structure in which the distance between the counter electrodes is substantially constant in order to avoid occurrence of arc discharge due to electric field concentration.
Examples of the electrode structure satisfying this condition include a parallel plate type, a cylindrical opposed flat plate type, a spherical opposed flat plate type, a hyperboloid opposed flat plate type, and a coaxial cylindrical type structure.
[0016]
The solid dielectric is placed on one or both of the opposing surfaces of the electrode. At this time, the solid dielectric and the electrode on the side to be installed are in close contact with each other and completely cover the facing surface of the electrode in contact therewith.
[0017]
Examples of the solid dielectric include plastics such as polytetrafluoroethylene and polyethylene terephthalate, glass, silicon dioxide, aluminum oxide, zirconium oxide, metal oxides such as titanium oxide, and double oxides such as barium titanate.
[0018]
The solid dielectric may have a sheet shape or a film shape, but preferably has a thickness of 0.05 to 4 mm. If it is too thick, a high voltage is required to generate discharge plasma, and if it is too thin, dielectric breakdown occurs when voltage is applied and arc discharge occurs.
[0019]
The distance between the electrodes is determined by the thickness of the solid dielectric, the magnitude of the applied voltage, and the size of the container or cylindrical body to be processed, but is preferably 1 to 50 mm.
When the distance between the electrodes is less than 1 mm, the distance between the electrodes and the container body or cylindrical body to be internally treated is insufficient. Moreover, when it exceeds 50 mm, it becomes difficult to generate uniform discharge plasma.
[0020]
FIG. 1 shows an example of a pulse voltage waveform. Waveforms (A) and (B) are impulse waveforms, waveform (C) is a square waveform, and waveform (D) is a modulation waveform. Although FIG. 1 shows a case where voltage application is repeated positive and negative, a pulse of a type in which voltage is applied to either the positive or negative polarity side may be used.
[0021]
The pulse voltage waveform in the present invention is not limited to the waveform mentioned here, but the ionization of the gas at the time of plasma generation is performed more efficiently as the rise time and fall time of the pulse are shorter.
[0022]
In particular, the pulse rise time and fall time are preferably 40 ns to 100 μs. If it is less than 40 ns, it is not practical, and if it exceeds 100 μs, the discharge state tends to shift to an arc and becomes unstable. More preferably, it is 50 ns to 5 μs.
Here, the rise time refers to the time during which the voltage change is positive continuously, and the fall time refers to the time during which the voltage change is negative continuously.
[0023]
Furthermore, modulation may be performed using pulses having different pulse waveforms, rise times, and frequencies. Such modulation is suitable for high speed continuous surface treatment.
[0024]
The frequency of the pulse electric field is preferably 0.5 to 100 kHz, and more preferably 1 to 100 kHz. If it is less than 0.5 kHz, the process takes too much time, and if it exceeds 100 kHz, arc discharge tends to occur.
[0025]
The time for applying one pulse electric field is preferably 1 μs to 1000 μs. If it is less than 1 μs, the discharge becomes unstable, and if it exceeds 1000 μs, it tends to shift to arc discharge. More preferably, it is 3 μs to 200 μs.
Here, the time during which one pulse electric field is applied is shown as an example in FIG. 2, but it means the continuous ON time of one pulse in a pulse electric field consisting of repetition of ON and OFF.
[0026]
The discharge is performed by applying a voltage. The magnitude of the voltage is appropriately determined, but it is preferable that the electric field strength be in the range of 1 to 100 kV / cm when applied to the electrode.
If it is less than 1 kV / cm, the process takes too much time, and if it exceeds 100 kV / cm, arc discharge tends to occur.
Further, in applying the pulse voltage, a direct current may be superimposed.
[0027]
FIG. 3 shows a block diagram of a power supply when such a pulse electric field is applied. FIG. 4 shows an equivalent circuit diagram of the power source. In FIG. 4, SW is a semiconductor element that functions as a switch. By using a semiconductor element having a turn-on time and a turn-off time of 500 ns or less as the switch, the electric field strength as described above is 1 to 100 kV / cm, and the pulse rise time and fall time are 40 ns to 100 μs. A certain high voltage and high speed pulse electric field can be realized.
[0028]
Hereinafter, the principle of the power supply will be briefly described with reference to the equivalent circuit diagram of FIG.
+ E is a positive DC voltage supply unit, and -E is a negative DC voltage supply unit. SW1 to SW4 are switch elements composed of the high-speed semiconductor elements as described above. D1-4 have shown the diode. I1 to I4 represent current flow directions.
[0029]
First, when SW1 is turned on, a positive load is charged in the direction of current I1 flow.
Next, after SW1 is turned off, the charged charge is charged in the direction of I3 through SW2 and D4 by turning on SW2 instantaneously.
Next, when SW3 is turned on after SW2 is turned off, the negative load is charged in the direction of current I2.
Next, after SW3 is turned off, the charged charge is charged in the direction of I4 through SW4 and D2 by turning on SW4 instantaneously.
By repeating the above series of operations, the output pulse of FIG. 5 can be obtained. Table 1 shows this operation table.
[0030]
[Table 1]

[0031]
The advantage of this circuit is that, even when the impedance of the load is high, the charged charges can be reliably discharged by operating SW2 and D4 or SW4 and D2, and a high-speed turn-on switch This is because the devices SW1 and SW3 can be used for high-speed charging, and as a result, a pulse signal with very fast rise and fall times can be obtained as shown in FIG.
[0032]
The shape of the container body or cylindrical body to be internally treated by the method of the present invention is preferably a hollow ordinary three-dimensional container body or cylindrical body having a shape having at least one opening. , Bottles, test tubes, syringe barrels, container bodies that are open on one side such as plastic cups, hoses, cylindrical bodies that are open on both sides, such as tubes, blow molded gasoline tanks, three-neck flasks, Examples include a container body or a cylindrical body having a plurality of openings such as a medical infusion container.
[0033]
In addition, the material of the container body or cylindrical body is not particularly limited, and examples thereof include ordinary plastics, engineering plastics, inorganic substances, and the like, for example, polyethylene, polypropylene, polystyrene, polycarbonate, polyethylene terephthalate, polyphenylene sulfide. Examples include inorganic substances such as plastics such as phyto, polytetrafluoroethylene and acrylic resins, glasses such as borosilicate glass, soda glass and quartz glass, ceramics such as alumina and zirconia, and metals such as aluminum, copper and stainless steel. It is done.
[0034]
The thickness of the container body or cylindrical body to be treated according to the present invention is preferably 0.05 to 4 mm, and when the thickness exceeds 4 mm, a high voltage is required to generate discharge plasma, When the thickness is less than 0.05 mm, dielectric breakdown occurs when voltage is applied, and arc discharge often occurs.
[0035]
In the container body or cylindrical body inner surface treatment of the present invention, various functions can be achieved by selecting a gas (hereinafter referred to as processing gas) present in the discharge plasma generation space inside the container body or cylindrical body. Or it can provide to the inner surface of a cylindrical body.
[0036]
When a fluorine-containing compound gas is used as the treatment gas, a fluorine-containing group can be formed on the inner surface of the container body or the cylindrical body, so that the surface energy can be lowered and a water-repellent surface can be obtained.
[0037]
Examples of the fluorine-containing compound include carbon tetrafluoride (CF ₄ ), carbon hexafluoride (C ₂ F ₆ ), propylene hexafluoride (CF ₃ CFCF ₂ ), and cyclofluorobutane (C ₄ F ₈ ). And fluorine-carbon compounds such as halogen-carbon compounds such as carbon trifluoride (CClF ₃ ) and sulfur hexafluoride (SF ₆ ).
From the viewpoint of safety, it is preferable to use carbon tetrafluoride, carbon hexafluoride, hexafluoropropylene, and octafluorocyclobutane that do not generate hydrogen fluoride, which is a harmful gas.
[0038]
Further, as a processing gas, an oxygen-containing compound, a nitrogen-containing compound, a sulfur-containing compound, oxygen, a mixed gas of oxygen and hydrogen, ozone, water vapor, a mixed gas of oxygen and an organic compound, or a container body or cylinder A hydrophilic group such as a carboxyl group, a carbonyl group, a hydroxyl group, and an amino group can be formed on the inner surface of the rod-like body to increase the surface energy and make the inner surface hydrophilic.
[0039]
Examples of the oxygen-containing compound include oxygen, ozone, water, carbon monoxide, carbon dioxide, nitrogen monoxide, nitrogen dioxide, alcohols such as methanol and ethanol, ketones such as acetone and methyl ethyl ketone, metanal, and ethanal. Organic compounds containing oxygen, such as aldehydes, can be used, and at least one of them can be used.
Furthermore, a mixture of an oxygen-containing compound and a hydrocarbon compound gas such as methane or ethane may be used.
Moreover, hydrophilicity is accelerated | stimulated by adding a fluorine-containing compound to an oxygen-containing compound at 50 volume% or less.
As the fluorine-containing compound, the same compounds as those described above may be used.
[0040]
Examples of the nitrogen-containing compound include nitrogen and ammonia, and a mixture of the nitrogen-containing compound and hydrogen may be used.
[0041]
Examples of the sulfur-containing compound include vaporized sulfur dioxide, sulfur trioxide, and sulfuric acid. These may be used alone or in combination of two or more.
[0042]
Alternatively, a hydrophilic polymer film can be laminated by treatment in an atmosphere of a monomer having a hydrophilic group and a polymerizable unsaturated bond in the molecule.
Examples of hydrophilic groups include hydroxyl groups, sulfonic acid groups, sulfonate groups, primary, secondary, tertiary amino groups, amide groups, quaternary ammonium bases, carboxyl groups, carboxylate groups, and the like.
Similarly, a hydrophilic polymer film can be laminated by using a monomer having a polyethylene glycol chain.
[0043]
Examples of the monomer include acrylic acid, methacrylic acid, acrylamide, methacrylamide, N, N-dimethylacrylamide, sodium acrylate, sodium methacrylate, potassium acrylate, potassium methacrylate, sodium styrenesulfonate, allyl alcohol, and allylamine. , Polyethylene glycol dimethacrylic acid ester, polyethylene glycol diacrylic acid ester and the like, and at least one of them can be used.
[0044]
Furthermore, a metal oxide thin film such as SiO ₂ , TiO ₂ , SnO ₂ is formed using a processing gas such as a metal metal-hydrogen compound, metal-halogen compound, metal alcoholate such as Si, Ti, Sn, etc. Electrical and optical functions can be imparted to the inner surface of the container body or cylindrical body.
[0045]
From the viewpoint of economy and safety, it is preferable to use a gas composition diluted with the following diluent gas as the processing gas supplied into the container body or cylindrical body.
Examples of the dilution gas include rare gases such as helium, neon, argon, and xenon, nitrogen gas, and the like, and at least one of these can be used.
In the method of the present invention, it is preferable to employ argon and / or nitrogen as the diluent gas.
Conventionally, surface treatment in the presence of helium has been performed under pressures near atmospheric pressure, but argon and nitrogen are less expensive gases than helium and have a higher molecular weight than helium. Therefore, a high-density plasma state can be realized stably, so that it has a great advantage in industrial production.
[0046]
DETAILED DESCRIPTION OF THE INVENTION
6 and 7 show an example of an apparatus for performing the surface treatment of the present invention.
These devices mainly include an alternating current power source (high voltage pulse power source) 1, a processing gas introduction tube 2, electrodes 3 and 4, a container body or cylindrical body 5 to be processed, and a container body or cylindrical body support. It comprises a body 6 and a processing gas discharge pipe 7.
The electrodes 3 and 4 may be provided with a solid dielectric (not shown in the drawing) on at least one whole surface on the surface where the electrodes 3 and 4 face each other.
[0047]
In the example of the inner surface treatment of the container body (test tube) in FIG. 6, the container body 5 whose inner surface is treated is disposed between both electrodes so that the electrodes 3 and 4 do not directly face each other.
The opening of the container body 5 is accurately fixed by the support 6 at the positions of the end portions of the electrodes 3 and 4, and the processing gas introduction pipe 2 is installed through the support 6.
The support 6 has a role of holding the container and suppressing the entry of other outside air into the processing gas, but does not completely seal the inside of the container.
[0048]
The processing gas passes through the processing gas supply tank and the flow rate control device (both are not shown in the figure), and the inside of the container body 5 is brought to a positive positive pressure from the processing gas introduction pipe 2. Supplied to be Excess gas is discharged little by little from the opening of the container 5 and the support 6.
Thereafter, a predetermined pulse electric field is applied to the electrodes 3 and 4, discharge plasma is generated inside the container body, and the region where the plasma is in contact is surface-treated.
[0049]
FIG. 7 shows an example of a cylindrical body. Both ends of the cylindrical body are held by the support 6, and the processing gas introduction pipe 2 and the processing gas discharge pipe 7 are connected. The processing method is basically the same as that of the container body of FIG.
[0050]
Although the material of the apparatus which performs the said surface treatment includes resin, glass, etc., it is not particularly limited. Metals such as stainless steel and aluminum can be used as long as the structure can be insulated from the electrodes.
[0051]
The inner surface treatment of the present invention may be performed by heating or cooling the container body or the cylindrical body, but is sufficient at room temperature.
The time required for the surface treatment is appropriately determined in consideration of the applied voltage, the type of processing gas, the mixed gas composition, and the like.
[0052]
In order to make it easier to understand the method for treating the inner surface of the container body or the cylindrical body of the present invention, examples will be described below.
Example 1
In the apparatus shown in FIG. 6, copper plates (100 × 20 mm, thickness 20 mm) are used for the electrodes 3 and 4, and the container body 5 is a polyethylene terephthalate blood collection tube (manufactured by Sekisui Chemical Co., Ltd., vacuum blood collection tube). Insepack-N, outer diameter: 15 mm, overall height: 100 mm) was used.
As shown in FIG. 6, the blood collection tube was disposed so as to be sandwiched between the electrodes 3 and 4, but the distance between the electrodes was 15 mm, and the outer diameter of the blood collection tube was 15 mm. The blood collection tube was fitted into the electrode.
[0053]
After that, while introducing 2000 sccm of nitrogen gas into the blood collection tube through the gas introduction tube 2, a pulse electric field (peak-peak value 12 kV) having a frequency of 8 kHz and a peak value of 6 kV is applied between the electrode 3 and the electrode 5. For a second.
Uniform light emission due to plasma was observed inside the blood collection tube.
A voltage waveform diagram of the applied pulse electric field is shown in FIG.
[0054]
With respect to the treated blood collection tube, together with the untreated blood collection tube, the contact angle was measured and the clot adhesion state was evaluated according to the measurement method described below.
<Contact angle evaluation>
2 μl of water droplets were dropped on the inner wall surface of the treated blood collection tube, and the static contact angle was measured using a contact angle measuring device (trade name: CA-D, manufactured by Kyowa Interface Science Co., Ltd.).
The untreated blood collection tube was 65 degrees, whereas the treated blood collection tube was 10 degrees, confirming that it was hydrophilic.
[0055]
<Evaluation of clot adherence>
Fresh rabbit blood was collected at a rate of 4-5 ml / tube, allowed to stand at room temperature, completely clotted, and then centrifuged at 3000 rpm for 5 minutes.
Thereafter, the state of serum separation and the state of clot component adhesion to the inner wall surface were visually observed.
As a result, compared with the untreated product, the treated product showed a better serum separation state, and the adhesion of clot components was much less.
[0056]
【The invention's effect】
The container body or cylindrical body inner surface processing method of the present invention is configured as described above, so that it can be carried out under a pressure in the vicinity of atmospheric pressure regardless of the type of gas atmosphere during processing. Since the container body or the cylindrical body itself functions as a chamber, there is no need for a chamber for generating plasma as in the prior art.
Therefore, the plasma processing apparatus is simplified and the amount of gas consumed is much less than that of the conventional method.
[0057]
[Brief description of the drawings]
FIG. 1 is a voltage waveform diagram showing an example of a pulsed electric field.
FIG. 2 is an explanatory diagram of the formation time of one pulse electric field.
FIG. 3 is a block diagram of a power supply that generates a pulsed electric field.
FIG. 4 is an equivalent circuit diagram of a power supply that generates a pulsed electric field.
FIG. 5 is a diagram of an output pulse signal corresponding to an operation table of a pulsed electric field.
FIG. 6 is an example of a discharge plasma processing apparatus of the present invention.
FIG. 7 is another example of the discharge plasma processing apparatus of the present invention.
8 is a waveform of a pulse electric field used in Example 1. FIG.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Pulse power supply 2 Gas inlet tube 3, 4 Electrode 5 Container body or cylindrical body which is a to-be-processed object 6 Support body 7 Processing gas discharge pipe

Claims (3)

Under a pressure close to atmospheric pressure, a container body or a cylindrical body in which a processing gas is supplied is disposed between opposing electrodes, and an electric field is applied between the electrodes to generate discharge plasma. A method for treating the inner surface of the container body or the cylindrical body,
As the processing gas, a gas composition diluted with nitrogen is used,
The electric field applied between the electrodes is a pulsed electric field, and the time during which one pulse is applied is shorter than the transition time from the plasma discharge state to the arc discharge state of the processing gas. A processing method for the inner surface of a container body or a cylindrical body using plasma.   2. The container using plasma according to claim 1, wherein the pulsed electric field has a voltage rise time and / or a fall time of 40 ns to 100 μs and an electric field strength of 1 to 100 kV / cm. A method for treating an inner surface of a body or a cylindrical body.   3. The plasma according to claim 1, wherein a time during which the one pulse is applied in the pulsed electric field is 1 μs to 1000 μs and a frequency is 0.5 kHz to 100 kHz. A method for treating the inner surface of a container body or a cylindrical body.

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