JPH0987891A - Electrodeposition coating method and electrodeposition coating device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the concentrated flow of a large current to part of materials to be coated and the formation of stepped coating films when the continuously transported materials to be coated enter an electrodeposition coating vessel in electrodeposition coating of an electrical entrance system of a low equipment cost and maintenance cost without the occurrence of a bipolar phenomenon. SOLUTION: The electric resistance value of the polar liquid in a diaphragm chamber M is set highest in the value of the entrance section diaphragm chamber M1 of the materials 2 to be coated and is set successively lower toward the progression direction of the materials 2 to be coated. Pure water is supplied to the diaphragm chamber M1 at the foremost end and is sent backward in a cascade system for this purpose. Further, the thickness w1 of the diaphragm chamber M at the foremost end is set max. and is successively decreased toward the progression direction of the materials 2 to be coated. As a result, the degradation in the throwing power by the voltage drop in the exit section is prevented.

Description

【発明の詳細な説明】Detailed Description of the Invention

【０００１】[0001]

【産業上の利用分野】本発明は電着塗装に関するもので
あり、特に隔膜室を用いて、通電入槽方式の電着塗装に
関するものである。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to electrodeposition coating, and more particularly to electrodeposition coating using a diaphragm chamber in an energization bath type.

【０００２】[0002]

【従来技術と問題点】電着塗装は、自動車などの金属板
を加工した製品にたいし古くより行われ、近年はカチオ
ン電着塗装が高耐食性の塗膜が得られるので、国内外で
広く行われている。カチオン電着塗装は、有機酸で中和
され、比抵抗値が３００〜１０００Ω−ｃｍに調整され
た水溶性の塗料を電着（塗装）槽内に建浴し、対向電極
である被塗物と、通常５〜２０個の隔膜室内に配設され
る主電極間に直流電圧を印加して行われる。これにより
負極性対向電極である被塗物表面にカチオン樹脂塗料が
析出し、一方隔膜室には有機酸が集中するので、純水を
供給して酸を除去し、塗料の中性を維持している。また
隔膜室内の極液濃度すなわち酸濃度は、比抵抗値または
比電導度を測定し、管理している。[Prior Art and Problems] Electrodeposition coating has been used for a long time on products such as automobiles processed with metal plates. In recent years, cationic electrodeposition coating has been widely used in Japan and abroad because it provides a highly corrosion-resistant coating. Has been done. Cationic electrodeposition coating is performed by bathing a water-soluble paint neutralized with an organic acid and having a specific resistance value of 300 to 1000 Ω-cm in an electrodeposition (coating) tank to form a counter electrode. Then, a DC voltage is applied between the main electrodes, which are usually arranged in 5 to 20 diaphragm chambers. This causes the cationic resin paint to deposit on the surface of the negative counter electrode, while the organic acid concentrates in the diaphragm chamber, so pure water is supplied to remove the acid and maintain the neutrality of the paint. ing. Further, the polar liquid concentration in the diaphragm chamber, that is, the acid concentration, is controlled by measuring the specific resistance value or the specific electric conductivity.

【０００３】ところで、被塗物は天井走行式コンベアー
に懸吊され、舟形に形成された電着槽内に連続的に浸漬
され、被塗物の進行に連動して、電着塗装が進行する
が、被塗物に直流電圧を印加する方式には、被塗物が通
電された状態で入槽するいわゆる通電入槽方式と、被塗
物が完全に電着槽に浸漬した後電圧を印加する、いわゆ
る全没通電方式とがある。いずれの場合も、塗膜の形成
されていない裸の状態で通電したとき、表面抵抗が小さ
く大電流が流れるため種々の問題が発生する。すなわち
通電入槽方式とした場合、液面が撹拌により、また被塗
物の入槽時の衝撃により、揺れるため均一に電着塗装で
きず、いわゆる段付き現象が発生する。そのため塗装品
質が低下し、研磨が必要となり、コストの上昇を招い
た。これを解決するため、主電極の位置を被塗物の入槽
地点から距離を離す方法が取られているが、十分な効果
が得られなかった。また全没通電方式の場合、段付き現
象が発生しない反面、大電流が通電と同時に流れるため
大きな電源や、集電装置が必要となる。またこの方式
は、被塗物の搬送が連続的に行われる場合、被塗物と搬
送装置の間を完全に絶縁せねばならないため、懸吊ハン
ガーや、集電装置の構造が複雑となり、装置コストが通
電入槽方式に比して著しく高価となった。また連続して
搬送される被塗物が通電されていない状態で入槽する時
に、先行する通電中の被塗物から電流が流れ、析出塗膜
を溶解するいわゆるバイポーラ現象が発生し、塗膜不良
を発生させた。そこで通電ゾーンを複数のゾーンに分割
し、入槽部に近いゾーンの電圧を低くし出槽部に向け
て、順次電圧を高くして印加する方法が取られている
が、上述の問題が完全には解決しないのみならず、低い
電圧ゾーンから高電圧ゾーンに移行するとき、集電子の
摺動部分でのスパークが避けられず、メンテナンスに多
大の費用を必要とした。By the way, the object to be coated is suspended on an overhead traveling type conveyor and continuously immersed in an electrocoating tank formed in a boat shape, and the electrodeposition coating proceeds in tandem with the progress of the object to be coated. However, the method of applying a DC voltage to the object to be coated is a so-called energization bath method in which the object to be coated is energized and a voltage is applied after the object is completely immersed in the electrodeposition tank. There is a so-called totally submerged energization method. In either case, when energized in a bare state where no coating film is formed, the surface resistance is small and a large current flows, which causes various problems. That is, in the case of the energization tank system, the liquid surface is shaken due to agitation and the impact at the time of entering the object to be coated, so that the electrodeposition coating cannot be performed uniformly and a so-called step phenomenon occurs. Therefore, the coating quality deteriorates, polishing is required, and the cost is increased. In order to solve this, a method of separating the position of the main electrode from the entry point of the object to be coated has been adopted, but a sufficient effect was not obtained. In addition, in the case of the totally submerged energization method, a step phenomenon does not occur, but a large current flows at the same time as energization, so that a large power source and a current collector are required. In addition, in this method, when the article to be coated is continuously conveyed, it is necessary to completely insulate between the article to be coated and the conveying device, so that the structure of the suspension hanger or the current collector becomes complicated, The cost is significantly higher than that of the energized bath system. Also, when the continuously conveyed coating object enters the tank in a non-energized state, a current flows from the preceding energized coating object, a so-called bipolar phenomenon occurs in which the deposited coating film is dissolved, and the coating film It caused a defect. Therefore, a method has been adopted in which the energization zone is divided into a plurality of zones, the voltage in the zone near the bath section is lowered, and the voltage is sequentially increased toward the bath section. Not only that, but also when moving from the low voltage zone to the high voltage zone, sparks on the sliding part of the current collector were unavoidable and required a great deal of cost for maintenance.

【０００４】一方電極は隔膜室内に配設され、隔膜室は
被塗物の進行方向に並行して、通常は複数の隔膜室が用
いられる。また電着塗装の進行にともない、隔膜室内極
液の酸濃度が次第に増大するので、通常５０〜１０００
ｋΩ−ｃｍの比抵抗を保有する純水を隔膜室に供給して
維持されるが、被塗物の入槽側隔膜室も、出槽側隔膜室
も極液の比抵抗を１０００〜３０００Ω−ｃｍになるよ
う一定に管理されていた。そのため通電入槽方式で電着
塗装した場合、入槽部においては、被塗物の電着面積が
小さいにも拘わらず、被塗物の表面抵抗が小さいため大
電流が流れ、僅かの揺れにたいしても、電流密度が変化
し、段付き現象を発生させる結果となっていた。一方出
槽部においては、隔膜室内極液の高い抵抗のため、被塗
物への印加が低下し、付き廻り性が低下する結果となっ
ていた。そこで隔膜室内電極の他に多数の裸電極を配設
すれば、付き廻り性が低下しないが、裸電極に集中した
酸が除去されず、しばしば電着塗料液を廃棄するか、ウ
ルトラフイルターにより濾液を廃棄して、余剰の酸を除
去せざるを得ず、作業の繁雑とコストの増大を招いてい
た。そこで本発明の課題とするのは、通電入槽方式の連
続式電着塗装において、段付き現象を発生させず、また
付き廻り性を低下させず、電着塗装を安定させる方法
と、装置を提供することである。On the other hand, the electrode is arranged in the diaphragm chamber, and a plurality of diaphragm chambers are usually used in parallel with the traveling direction of the object to be coated. Further, as the electrodeposition coating progresses, the acid concentration of the polar liquid in the diaphragm chamber gradually increases.
Pure water having a specific resistance of kΩ-cm is supplied to and maintained in the diaphragm chamber, but both the inlet-side diaphragm chamber and the outlet-side diaphragm chamber of the object to be coated have a specific resistance of 1000 to 3000Ω-. It was controlled so that it would be cm. Therefore, when the electrodeposition coating is carried out by the energization bath method, a large current flows due to the small surface resistance of the coating object in the bath section, despite the small electrodeposition area of the coating object, against slight shaking. However, the current density was changed, resulting in a step phenomenon. On the other hand, in the tank portion, the high resistance of the polar liquid in the diaphragm causes a decrease in the application to the object to be coated, resulting in a decrease in throwing power. Therefore, if a large number of bare electrodes are provided in addition to the diaphragm inner electrodes, the throwing power does not deteriorate, but the acid concentrated on the bare electrodes is not removed, and the electrodeposition coating solution is often discarded, or the filtrate is filtered with an ultrafilter. Had to be discarded to remove excess acid, resulting in complicated work and increased cost. Therefore, an object of the present invention is to provide a method and a device for stabilizing electrodeposition coating without causing a step phenomenon in the continuous electrodeposition coating of the energization bath method and without reducing the throwing power. Is to provide.

【０００５】[0005]

【課題を解決する手段】上記の問題を解決するために、
本発明が提供する手段は、主電極を内蔵し、被塗物の進
行方向と平行して配設される複数の隔膜室を具備する電
着塗装槽に、連続的に搬送される被塗物が、通電した状
態で入槽して行われる電着塗装において、被塗物の入槽
地点に最も近い隔膜室内極液の電気抵抗を最高値となる
ようにし、以下被塗物の進行方向に順次減少させるよう
調節することを特徴とするものであり、隔膜室内極液の
電気抵抗値の調節が、被塗物の入槽地点に最も近い隔膜
室に純水を供給し、比抵抗値を最高値となるようにし、
以下各隔膜室内の極液を被塗物の進行方向に、順次カス
ケード式に供給することにより行われることと、隔膜室
内極液の電気抵抗値の調節が、被塗物の入槽地点に最も
近い隔膜室の厚みを最高にし、以下被塗物の進行方向
に、厚みを順次減少することにより行われることを含
む。[Means for Solving the Problems] In order to solve the above problems,
Means provided by the present invention is an article to be continuously conveyed to an electrodeposition coating tank having a main electrode and a plurality of diaphragm chambers arranged in parallel with the traveling direction of the article to be coated. However, in the electrodeposition coating that is carried out with the tank energized, the electric resistance of the polar liquid in the diaphragm chamber closest to the entry point of the object to be coated is set to the maximum value. It is characterized in that it is adjusted so as to gradually decrease, and the electrical resistance value of the polar fluid in the diaphragm chamber is adjusted by supplying pure water to the diaphragm chamber closest to the entry point of the object to be coated, To the highest value,
The following is performed by sequentially supplying the polar liquid in each septum chamber in the traveling direction of the article to be coated in a cascade manner, and adjusting the electric resistance value of the polar fluid in the membrane chamber is most effective at the entry point of the article to be coated. This includes maximizing the thickness of the adjacent diaphragm chamber and successively decreasing the thickness in the advancing direction of the article to be coated.

【０００６】[0006]

【作用】上記の手段によれば、被塗物の入槽地点に最も
近い隔膜室内極液の電気抵抗を最高値となるようにし、
以下各隔膜室内極液の電気抵抗値を、入槽部から出槽部
に向けて順次低下させるので、入槽部の隔膜面電位が最
も低く、以下順次高くなる。それゆえ被塗物の入槽部に
おいて電流が急激に集中して流れず、段付きが発生しな
い。また出槽部において、電圧降下が小さく、隔膜面電
位が高いので、付き廻り性が低下せず、かつ電流効率が
低下しない。さらに純水を先頭隔膜室に供給し、各隔膜
室に被塗物の進行方向に順次カスケード式に供給すれ
ば、抵抗値が入槽部から順次低減し、従って隔膜面電位
が順次高くなるように自動的に調節できる。さらに廃棄
する酸濃度が最も高くなるので、純水使用量が低下す
る。また先頭隔膜室の厚みを最高にし、以下順次厚みを
低下すれば、隔膜室の電気抵抗が、入槽部から順次自動
的に低下し、隔膜面電位が順次高くなる。According to the above means, the electric resistance of the polar liquid in the diaphragm chamber closest to the entry point of the article to be coated is maximized,
Since the electrical resistance value of the polar liquid in each diaphragm chamber is successively decreased from the tank part to the tank part, the diaphragm surface potential of the tank part is the lowest, and then sequentially increases. Therefore, the current does not suddenly concentrate and flow in the tank portion of the object to be coated, and no step is generated. In addition, since the voltage drop is small and the diaphragm surface potential is high in the bath section, the throwing power does not decrease and the current efficiency does not decrease. Further, if pure water is supplied to the leading diaphragm chambers and then sequentially supplied to each diaphragm chamber in the advancing direction of the object to be coated, the resistance value is gradually reduced from the tank portion, and thus the diaphragm surface potential is gradually increased. Can be automatically adjusted to. Furthermore, since the concentration of the acid to be discarded becomes the highest, the amount of pure water used decreases. Further, if the thickness of the leading diaphragm chamber is maximized and then the thickness is successively decreased, the electrical resistance of the diaphragm chamber will automatically and sequentially decrease from the bath section, and the diaphragm surface potential will successively increase.

【０００７】[0007]

【実施例１】本発明の実施態様を実施例で示す。図１は
本発明を示す電着塗装装置の縦断面図であり６個の隔膜
室Ｍ_１〜Ｍ_６が配設されている。また図２は本実施例の
水平断面の１部を示す図である。Example 1 An embodiment of the present invention will be shown by way of example. FIG. 1 is a vertical sectional view of an electrodeposition coating apparatus showing the present invention, in which six diaphragm chambers M _{1 to} M ₆ are arranged. FIG. 2 is a diagram showing a part of the horizontal cross section of this embodiment.

【０００８】図１において、被塗物２は図の左側から右
側方向に移動し、Ｐ地点に入槽し、被塗物の進行に従っ
て電着塗装が進行し、Ｑ地点から出槽する。その間被塗
物２は、図示しない集電子を通じて集電板５により、通
常はアースされ、負極性電位を保持する。隔膜室Ｍは、
図２に示すごとく電着塗装槽４の槽壁に沿って、間隔の
最短距離１を約３０ｃｍとし、被塗物２の進行方向に並
行して配設される。最先端の隔膜室Ｍ_１は、図１に示す
ごとく、Ｐ点から３〜５ｍ離れた位置に配設され、以下
各隔膜室が適宜の電極密度で配設される。隔膜室Ｍの数
は、通常に用いられる数でも十分効果が得られるが、本
発明においては、できるだけ多い程、その効果が大きく
なるので、３個以上が好ましく、さらに５個以上とする
のがより好ましい。隔膜室Ｍ_１〜Ｍ_６内の主電極Ｄ_１〜
Ｄ_６および裸電極Ｄ_７、Ｄ_８には図示しない電源により
常時正極性直流電圧が印加される。すなわち被塗物は通
電入槽し、通電出槽する。In FIG. 1, the article to be coated 2 moves from the left side to the right in the figure, enters the point P, and the electrodeposition coating proceeds as the article to be coated advances, and leaves the point Q. In the meantime, the article to be coated 2 is normally grounded by the current collector plate 5 through a current collector (not shown) to maintain the negative potential. The diaphragm chamber M is
As shown in FIG. 2, the shortest distance 1 is about 30 cm along the wall of the electrodeposition coating tank 4 and the electrodes are arranged in parallel with the traveling direction of the article to be coated 2. As shown in FIG. 1, the most advanced diaphragm chamber M ₁ is arranged at a position 3 to 5 m away from the point P, and each diaphragm chamber is arranged with an appropriate electrode density. The number of diaphragm chambers M can be sufficient even if it is a number that is normally used, but in the present invention, the larger the number, the greater the effect. Therefore, the number is preferably 3 or more, and more preferably 5 or more. More preferable. Main electrodes D ₁ -in the diaphragm chambers M ₁ -M ₆
A positive DC voltage is constantly applied to D ₆ and bare electrodes D ₇ and D ₈ by a power source (not shown). That is, the object to be coated is energized and deenergized.

【０００９】隔膜室Ｍ内への純水または極液の供給は、
図１に示すごとくカスケード方式で行われる。すなわち
入槽部隔膜室Ｍ_１には純水貯蔵槽１０からポンプ１２で
圧送し、隔膜室Ｍ_１からは溢流管１３によりオーバーフ
ローし隔膜室Ｍ_２に供給される。以下順次Ｍ_２からＭ_３
へ、Ｍ_３からＭ_４へオーバフローでカスケード式に最終
隔膜室Ｍ_６まで供給され、排水槽Ｚに排出される。隔膜
室Ｍの数が多いときは、図１に示すごとく、途中にクッ
ションタンク１４を配設して、ポンプ１６で圧送すれば
よい。隔膜室Ｍの極液濃度は、比電導度計または比抵抗
計２０、２１を配設して、先頭および最終隔膜室の比電
導度または比抵抗を測定し、純水供給量を調節するのが
好ましい。純水または極液の供給は、各隔膜室に個別に
行ってもよいが、図１に示すごとく、カスケード式にす
れば、各隔膜室の電気抵抗が、被塗物の進行方向に、自
動的に順次低下し、隔膜面電位が自動的に順次高くなる
ので好ましい。また酸濃度の濃い極液を排出するので、
個別供給方式に比して、純水供給量を著しく低減でき
る。The pure water or the polar liquid is supplied to the diaphragm chamber M by
As shown in FIG. 1, it is performed by a cascade method. That is, Iriso section diaphragm chamber M ₁ is pumped by pump 12 from the pure water storage tank 10, from the diaphragm chamber M ₁ is supplied to the diaphragm chamber M ₂ overflows by downcomers 13. The following M ₂ to M ₃
To the final diaphragm chamber M ₆ in a cascade manner from M ₃ to M ₄ by overflow, and is discharged to the drain tank Z. When the number of diaphragm chambers M is large, as shown in FIG. 1, a cushion tank 14 may be arranged in the middle and pumped by a pump 16. As for the polar liquid concentration in the diaphragm chamber M, the specific electric conductivity meters or the specific resistance meters 20 and 21 are provided to measure the specific electric conductivity or the specific resistance of the leading and final diaphragm chambers to adjust the pure water supply amount. Is preferred. The pure water or the polar solution may be supplied to each diaphragm chamber individually, but if a cascade type is used as shown in FIG. 1, the electric resistance of each diaphragm chamber is automatically adjusted in the traveling direction of the object to be coated. It is preferable that the diaphragm surface potential automatically and sequentially increases. Also, since the polar liquid with a high acid concentration is discharged,
Compared to the individual supply method, the pure water supply amount can be significantly reduced.

【００１０】隔膜室Ｍの厚みｗ、すなわち主電極板Ｄか
ら被塗物側に張られた隔膜Ｂまでの距離は、厚い程電気
抵抗が大きく効果的であり、図２に示すごとく、入槽部
隔膜室Ｍ_１の厚みｗ_１を厚くし、順次被塗物の進行方向
に薄くすると、電気抵抗値が、被塗物の進行方向に順次
低下し、隔膜面電位が順次高くなるので好ましい。それ
ゆえ少なくも最先端の厚みｗ_１を厚くするのが好まし
い。またその実際上の厚みは通常は３ｃｍ以上が好まし
く、５ｃｍ以上がさらに好ましい。しかし厚くすれば、
それだけ電着槽が大きくなるので、１５ｃｍ以下とすれ
ばよい。またカスケード式の純水供給と併用すれば相乗
効果が発揮できる。As the thickness w of the diaphragm chamber M, that is, the distance from the main electrode plate D to the diaphragm B stretched on the side of the object to be coated, the larger the electric resistance, the more effective it is. As shown in FIG. It is preferable to increase the thickness w ₁ of the partial diaphragm chamber M ₁ and successively decrease the thickness in the advancing direction of the article to be coated, because the electric resistance value is gradually decreased in the traveling direction of the article to be coated and the diaphragm surface potential is sequentially increased. Therefore, it is preferable to increase the thickness w ₁ at the leading edge at least. The practical thickness is usually preferably 3 cm or more, more preferably 5 cm or more. But thicker,
Since the electrodeposition tank becomes larger by that much, it should be 15 cm or less. When used in combination with cascade type pure water supply, a synergistic effect can be exhibited.

【００１１】最先端隔膜室Ｍ_１内の極液濃度は、電着塗
料の比抵抗の１０倍以上とするのが好ましく、実際上は
電着塗料の比抵抗値が、３００〜１０００Ω−ｃｍなの
で、最先端隔膜室Ｍ_１の比抵抗を３０００Ω−ｃｍ以上
とするのが好ましく、１００００Ω−ｃｍ以上とするの
がより好ましく、さらに２００００Ω−ｃｍ以上とする
のがより好ましい。また最後尾隔膜室の極液濃度は、電
着塗料自身の比抵抗値または比電導度値に近い程、付き
廻り性が低下しないので好ましく、比抵抗計２０、２１
により純水供給量を調節すればよい。また最後尾隔膜室
の後、さらに付き廻り性を向上するため、図１に示すご
とくパイプ状の裸電極を１〜２本被塗物の底部分に面し
て配設してもよい。The polar liquid concentration in the most advanced diaphragm chamber M ₁ is preferably 10 times or more the specific resistance of the electrodeposition coating, and in practice the specific resistance of the electrodeposition coating is 300 to 1000 Ω-cm. The specific resistance of the most advanced diaphragm chamber M ₁ is preferably 3000 Ω-cm or more, more preferably 10000 Ω-cm or more, and further preferably 20000 Ω-cm or more. Further, the closer the polar liquid concentration in the rearmost diaphragm chamber is to the specific resistance value or the specific electric conductivity value of the electrodeposition coating itself, the more preferable the throwing power is.
The pure water supply amount may be adjusted by. Further, after the rearmost diaphragm chamber, in order to further improve the throwing power, one or two pipe-shaped bare electrodes may be arranged facing the bottom portion of the article to be coated, as shown in FIG.

【００１２】[0012]

【発明の効果】本発明によれば、隔膜室の電気抵抗が入
槽部が高く、以下被塗物の進行方向に順次低下させるの
で、隔膜面電位が入槽部が低く、被塗物の進行方向に順
次高くなる。それゆえ電着槽への被塗物の入槽時に、急
激な電流が流れないので、段付きが発生せず均一な塗膜
が形成され、外観品質が向上する。さらに出槽部におけ
る電圧降下が小さく、付き廻り性が低下せず、電流効率
が向上する。従って耐食性が向上し、電気代が低下す
る。また裸電極の配設位置が、被塗物の表面抵抗が大き
く、従って電流量の小さい最後尾に限定できるので、酸
の除去が確実に行われる。それゆえ、特別に電着塗料を
廃棄する必要がなくなり、塗料コストが低減する。また
純水を最先端の隔膜室に供給して、以下順次カスケード
式に極液を送れば、各隔膜室の極液濃度、従って電気抵
抗が、最先端が高く、被塗物の進行方向に順次低くなる
ように、自動的に調節され、安定した電着塗装ができ
る。また濃度の高い極液を廃棄するので、純水使用量が
減少し、コストが低減する。また最先端の隔膜室の厚み
を最高にし、以下厚みを順次減少すれば、各隔膜室の電
気抵抗が、被塗物の進行方向に減少するように自動的に
調節できるので、安定した電着塗装ができる。According to the present invention, since the electric resistance of the diaphragm chamber is high in the tank portion and is gradually decreased in the advancing direction of the object to be coated, the diaphragm surface potential is low in the tank portion and the object to be coated is lowered. It becomes higher in the direction of travel. Therefore, when a material to be coated enters the electrodeposition tank, a rapid current does not flow, a step is not generated, a uniform coating film is formed, and the appearance quality is improved. Further, the voltage drop in the tank portion is small, the throwing power does not deteriorate, and the current efficiency improves. Therefore, the corrosion resistance is improved and the electricity bill is reduced. Further, the position where the bare electrode is disposed can be limited to the tail end where the surface resistance of the object to be coated is large and thus the amount of current is small, so that the acid can be reliably removed. Therefore, it is not necessary to dispose of the electrodeposition paint specially, and the paint cost is reduced. In addition, if pure water is supplied to the most advanced diaphragm chamber and then the polar solution is sent sequentially in a cascade manner, the concentration of the polar solution in each diaphragm chamber, and hence the electrical resistance, will be high at the leading edge and It is automatically adjusted so that it gradually decreases, and stable electrodeposition coating is possible. Further, since the highly concentrated polar liquid is discarded, the amount of pure water used is reduced and the cost is reduced. In addition, if the thickness of the most advanced diaphragm chamber is maximized and the thickness is successively reduced, the electrical resistance of each diaphragm chamber can be automatically adjusted so as to decrease in the traveling direction of the object to be coated. Can be painted.

【００１３】本発明はカチオン型塗料について説明した
が、本発明はこれに限定するものでなく、陽極に塗膜が
析出し中和剤のアミンが、陰極を内蔵する隔膜室に集中
するアニオン型樹脂塗料を用いての、通電入槽方式の電
着塗装の場合も、本発明を用い得ることは言うまでもな
い。Although the present invention has been described with respect to a cationic type coating, the present invention is not limited to this, and an anionic type in which a coating film is deposited on the anode and the amine as the neutralizing agent is concentrated in the diaphragm chamber containing the cathode. It goes without saying that the present invention can also be used in the case of electrodeposition coating using a resin coating material, which is an electric bath.

【図面の簡単な説明】[Brief description of drawings]

【図１】 本発明の実施例を示す縦断面図FIG. 1 is a vertical sectional view showing an embodiment of the present invention.

【図２】 本発明の実施例の水平断面の１部を示す図FIG. 2 is a diagram showing a part of a horizontal cross section of an embodiment of the present invention.

【符号の説明】[Explanation of symbols]

２、被塗物 ４、電着塗装槽 Ｍ、隔膜室 Ｄ、主電極 １０、純水貯槽 ２０、２１は、比抵抗計または比電導度計 2, the object to be coated 4, the electrodeposition coating tank M, the diaphragm chamber D, the main electrode 10, the pure water storage tanks 20 and 21 are a resistivity meter or a conductivity meter.

Claims (4)

【特許請求の範囲】[Claims] 【請求項１】 主電極を内蔵し、被塗物の進行方向と平
行して配設される複数の隔膜室を具備する電着塗装槽に
漣続的に搬送される被塗物が、通電した状態で入槽して
行われる電着塗装において、被塗物の入槽地点に最も近
い隔膜室内極液の電気抵抗値を最高値となるようにし、
以下被塗物の進行方向に順次減少させるよう調節するこ
とを特徴とする電着塗装方法1. An object to be coated, which is continuously transported to an electrodeposition coating tank having a plurality of diaphragm chambers, which incorporates a main electrode and is arranged in parallel with a traveling direction of the object to be coated, is energized. In the electrodeposition coating carried out in the tank in the state, the electric resistance value of the polar liquid in the diaphragm chamber closest to the entry point of the object to be coated becomes the maximum value,
Hereinafter, the electrodeposition coating method is characterized in that it is adjusted so as to gradually decrease in the traveling direction of the object to be coated. 【請求項２】 隔膜室内極液の電気抵抗値の調節が、被
塗物の入槽地点に最も近い隔膜室に純水を供給し、比抵
抗値を最高値となるようにし、以下各隔膜室内の極液
を、被塗物の進行方向に、順次カスケード式に供給する
ことにより行われることを特徴とする請求項１に記載の
電着塗装方法2. The adjustment of the electric resistance value of the polar liquid in the diaphragm chamber is performed by supplying pure water to the diaphragm chamber closest to the entry point of the object to be coated so that the specific resistance value becomes the maximum value. The electrodeposition coating method according to claim 1, wherein the electrodeposition coating is performed by sequentially supplying the polar liquid in the chamber in a traveling direction of the article to be coated. 【請求項３】 隔膜室内極液の電気抵抗置の調節が、被
塗物の入槽地点に最も近い隔膜室の厚みを最高にし、以
下被塗物の進行方向に、厚みを順次減少することにより
行われることを特徴とする請求項１に記載の電着塗装方
法3. The adjustment of the electrical resistance of the polar liquid in the diaphragm chamber is such that the thickness of the diaphragm chamber closest to the entry point of the article to be coated is maximized, and the thickness is successively reduced in the advancing direction of the article to be coated. The electrodeposition coating method according to claim 1, wherein 【請求項４】 被塗物を通電状態で電着塗装槽に浸漬す
る手段、被塗物の進行方向に並列に配設される複数の隔
膜室、先頭部隔膜室への純水供給手段、および各隔膜室
内の極液を順次後方にカスケード式に送る手段、および
少なくも先頭部隔膜室の比抵抗置または比電導度を測定
する手段を具備する電着塗装装置4. A means for immersing an object to be coated in an electrodeposition coating tank in an energized state, a plurality of diaphragm chambers arranged in parallel in the traveling direction of the object to be coated, and a means for supplying pure water to the leading diaphragm chamber, And an electrodeposition coating apparatus having means for sequentially sending the polar liquid in each diaphragm chamber backward in a cascade manner, and means for measuring at least the specific resistance position or the electric conductivity of the leading diaphragm chamber.