JPH1018094A - Management method for cation type electrodeposition coating bath solution - Google Patents

Management method for cation type electrodeposition coating bath solution

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Publication number
JPH1018094A
JPH1018094A JP19136796A JP19136796A JPH1018094A JP H1018094 A JPH1018094 A JP H1018094A JP 19136796 A JP19136796 A JP 19136796A JP 19136796 A JP19136796 A JP 19136796A JP H1018094 A JPH1018094 A JP H1018094A
Authority
JP
Japan
Prior art keywords
electrodeposition coating
tank
solution
bath
metal ions
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
JP19136796A
Other languages
Japanese (ja)
Inventor
Toshikatsu Hamano
利勝 浜野
Kanehiro Tanaka
謙宏 田中
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Ohara & Co Ltd
OHARA KAKO KK
AGC Inc
Original Assignee
Ohara & Co Ltd
OHARA KAKO KK
Asahi Glass Co Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Ohara & Co Ltd, OHARA KAKO KK, Asahi Glass Co Ltd filed Critical Ohara & Co Ltd
Priority to JP19136796A priority Critical patent/JPH1018094A/en
Publication of JPH1018094A publication Critical patent/JPH1018094A/en
Pending legal-status Critical Current

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  • Application Of Or Painting With Fluid Materials (AREA)
  • Water Treatment By Electricity Or Magnetism (AREA)

Abstract

PROBLEM TO BE SOLVED: To efficiently remove acid radicals and metal ions by taking part of a bath solution out of an electrodeposition coating vessel and subjecting this solution to electrodialysis. SOLUTION: A ferrous metallic anode and a material to be coated as cathode are arranged in the electrodeposition coating vessel 10. On the other hand, anion exchange membranes and cation exchange membranes are alternately arranged in an electrodialysis vessel 11. The coating bath liquid 12 partly taken out of the electrodeposition coating vessel 10 is sent to the dialysis cell 11 where the acids and metal ions 13 are removed; thereafter, the bath 14 is returned to the coating vessel 10. As a result, the metal ions eluting from the electrodes and the material to be coated in addition to the acids increasing with the progression of the electrodeposition coating are efficiently removed and the accumulation thereof is prevented. Then, the well maintaining of the quality of the coated film is made possible. Since the removal of the acids and metal ions is executed outside the electrodeposition coating vessel 10, the size of the vessels is reduced and the amt. of the bath solution is decreased.

Description

【発明の詳細な説明】DETAILED DESCRIPTION OF THE INVENTION

【０００１】[0001]

【発明の属する技術分野】本発明は、カチオン型電着塗
装における電着塗装浴液の管理方法に関し、特にカチオ
ン型電着塗装において電着塗装浴液中に電着の進行につ
れて増加する酸及び金属イオンの除去を通じての電解塗
装浴液の管理方法に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for managing an electrodeposition bath solution in a cationic electrodeposition coating, and more particularly, to an acid and an acid which increase as the electrodeposition progresses in the electrodeposition bath in the cationic electrodeposition coating. The present invention relates to a method for managing an electrolytic coating solution through removal of metal ions.

【０００２】[0002]

【従来の技術】カチオン型電着塗装は、図３のように電
着塗装槽１内の電着塗装浴液２中に、電導体である被塗
装物（例えば自動車のボディ−）３を浸漬して陰極とな
し、カチオン型電着塗装浴液中に配置された陽極４ａ、
４ｂと陰極３との間に直流電流を通じることにより、被
塗装物を電気的に塗装する方法である。カチオン型電着
塗装では陰極側では２Ｈ2 Ｏ＋２ｅ- → ２ＯＨ- ＋
Ｈ2 、また陽極側では２Ｈ2 Ｏ→４Ｈ+ ＋Ｏ2 ＋４ｅ-
の反応が起こっている。2. Description of the Related Art In a cationic electrodeposition coating, as shown in FIG. 3, an object to be coated (an automobile body, for example) 3 is immersed in an electrodeposition coating bath solution 2 in an electrodeposition coating tank 1. An anode 4a placed in a cationic electrodeposition coating bath
This is a method in which an object to be coated is electrically coated by passing a direct current between the cathode 4 and the cathode 4b. In the cationic electrodeposition coating, 2H 2 O + 2e − → 2OH − + on the cathode side
H 2 , and 2H 2 O → 4H + + O 2 + 4e − on the anode side
The reaction is taking place.

【０００３】電着塗装浴液（電着塗料含有液）は、顔料
を樹脂加工したもの（塗料成分）を水に分散もしくは溶
解させた水性塗料で、樹脂としては例えばエポキシ樹脂
等を主骨格としこれにアミンなどを反応させてカチオン
性官能基を導入し、中和剤である酸で中和することによ
り水に分散もしくは溶解するようにされている。[0003] An electrodeposition coating bath (liquid containing an electrodeposition coating) is an aqueous coating obtained by dispersing or dissolving a pigment-processed resin (coating component) in water. The resin has, for example, an epoxy resin as a main skeleton. This is reacted with an amine or the like to introduce a cationic functional group, and neutralized with an acid as a neutralizing agent to disperse or dissolve in water.

【０００４】直流電流を通じると陰極（被塗装物）側で
は、正に荷電している塗料成分は陰極（被塗装物）側表
面に移動して凝固し、陰極表面に塗膜を形成する。塗膜
が形成されるに従い電着塗装浴液中の酸が遊離し酸濃度
が上昇するようになるが、酸濃度が上昇し過ぎると塗料
成分の凝固性が低下し塗装に悪影響を与える。従って電
着塗装浴液のｐＨが所定の範囲（例えばｐＨ５．５〜
６．５）におさまるように酸を除去する必要がある。従
来そのために、電着塗装槽内の陽極４ｂの近傍をアニオ
ン交換膜からなる隔膜５で区画することにより陽極側に
酸根を集め、集めた酸根を酸として電着塗装槽外に除去
することが行われている。When a direct current is passed, on the cathode (object) side, the positively charged paint component moves to the surface of the cathode (object) and solidifies to form a coating film on the cathode surface. As the coating film is formed, the acid in the electrodeposition bath solution is liberated to increase the acid concentration. However, if the acid concentration is too high, the coagulability of the coating components is reduced, which adversely affects the coating. Therefore, the pH of the electrodeposition bath solution is within a predetermined range (for example, pH 5.5 to 5.5).
It is necessary to remove the acid so that 6.5) is satisfied. Conventionally, for this purpose, it is possible to collect acid radicals on the anode side by partitioning the vicinity of the anode 4b in the electrodeposition coating tank with a diaphragm 5 made of an anion exchange membrane, and remove the collected acid radicals as acid outside the electrodeposition coating tank. Is being done.

【０００５】[0005]

【発明が解決しようとする課題】しかし、カチオン型電
着塗装槽内の陽極の近傍を隔膜で区画するようにする
と、それだけで余分のスペ−スを要し、電着塗装槽が大
型になり、必要以上の電着塗装浴液を保持しなくてはな
らないという欠点がある。また大型の被塗装物が電着塗
装槽に出入りするため、隔膜が破損し易いという欠点も
あり、隔膜の形状、設置方法等に関して設計上かなり制
約を受ける。However, when the vicinity of the anode in the cationic electrodeposition coating tank is divided by a diaphragm, extra space is required by itself, and the electrodeposition coating tank becomes large. However, there is a disadvantage that an excessive amount of electrodeposition coating bath must be retained. Further, since a large object to be coated enters and exits the electrodeposition coating tank, the diaphragm is liable to be damaged, and the shape and installation method of the diaphragm are considerably restricted in design.

【０００６】また隔膜（アニオン交換膜）による酸根を
除去する電流効率が、被塗装物への塗料の電着電流効率
より高いため、すべての陽極を隔膜で区画すると必要以
上に酸を除去しすぎてしまうので、図３のようにアニオ
ン交換膜で区画していない陽極（裸陽極）４ａも併用さ
れているが、隔膜で区画された陽極と、裸陽極との面積
割合や電流密度の割合などを考慮する必要があるなど調
整が面倒である。Further, since the current efficiency for removing acid radicals by a membrane (anion exchange membrane) is higher than the current efficiency of electrodeposition of a coating material on an object to be coated, if all anodes are partitioned by the membrane, acid is removed more than necessary. Therefore, as shown in FIG. 3, the anode (bare anode) 4a not partitioned by the anion exchange membrane is also used, but the area ratio of the anode partitioned by the diaphragm and the bare anode, the ratio of the current density, etc. It is troublesome to adjust such that it is necessary to consider

【０００７】さらに、陽極電極には、鉄、ニッケル、ス
テンレス等の鉄系材料が使用されているので、陽極、特
に裸陽極４ａから溶出した鉄イオン（Ｆｅ+ + ）などが
電着塗装浴液中に増加蓄積し被塗装物に電析するように
なる。さらに被塗装物には電着塗装前に燐酸亜鉛等によ
り表面処理が施されていることが多く、その結果として
亜鉛イオンが、また電着塗料の成分である顔料からの鉛
イオンなどが電着塗装浴液中に溶出し酸化されて酸化物
となり同様に塗膜に混入し、塗膜の品質を低下させる。Further, since iron materials such as iron, nickel, and stainless steel are used for the anode electrode, the anode, especially iron ions (Fe + + ) eluted from the bare anode 4a are subjected to the electrodeposition coating bath solution. It accumulates and deposits on the object to be coated. Further, the object to be coated is often subjected to a surface treatment with zinc phosphate or the like before the electrodeposition coating. As a result, zinc ions and lead ions from a pigment which is a component of the electrodeposition paint are electrodeposited. It elutes into the coating solution and is oxidized into an oxide, which is similarly mixed into the coating film to lower the quality of the coating film.

【０００８】本発明は、電着塗装の進行と共に増加する
酸に加えて、電極や被塗装物から溶出する金属イオンも
効率よく除去してその蓄積を防止するカチオン型電着塗
装浴液の管理方法を提供することを目的とするものであ
る。[0008] The present invention provides a method for managing a cationic electrodeposition bath solution for efficiently removing metal ions eluted from an electrode or an object to be coated, in addition to an acid which increases with the progress of electrodeposition coating, and preventing the accumulation thereof. It is intended to provide a method.

【０００９】[0009]

【課題を解決するための手段】本発明では、鉄系金属陽
極を用いた電着塗装槽内において行われるカチオン型電
着塗装において、電着塗装浴液の一部を電着塗装槽から
取り出し、イオン交換膜を組み込んだ電気透析槽に導入
して電気透析することにより、該電着塗装浴液中に含ま
れる酸根及び金属イオンを除去した後、電着塗装槽に循
環することを特徴とする。According to the present invention, in a cationic electrodeposition coating performed in an electrodeposition coating tank using an iron-based metal anode, a part of the electrodeposition coating bath is taken out from the electrodeposition coating tank. Introducing an ion exchange membrane into an electrodialysis tank and conducting electrodialysis to remove acid radicals and metal ions contained in the electrocoat bath, and then circulating the electrocoat tank. I do.

【００１０】鉄系金属陽極としては、鉄、ニッケルなど
の周期律表の鉄族金属、ステンレス陽極などが挙げられ
る。電着塗装浴液中の金属イオンとしては被塗装物から
溶出した亜鉛イオンがあり、陽極から溶出した鉄イオ
ン、ニッケルイオンが挙げられる。さらに中和剤として
用いる酸としては酢酸、蟻酸、乳酸等の有機酸が挙げら
れる。Examples of the iron-based metal anode include iron group metals such as iron and nickel, and stainless steel anodes. Metal ions in the electrodeposition bath solution include zinc ions eluted from the object to be coated, and iron ions and nickel ions eluted from the anode. Further, examples of the acid used as the neutralizing agent include organic acids such as acetic acid, formic acid, and lactic acid.

【００１１】電気透析槽は全体を締付けることにより組
み立てられたフィルタプレス型装置が好ましくは使用さ
れる。電気透析槽の陽極と陰極との間にカチオン交換膜
及びアニオン交換膜が交互に配置され、希釈室に電着塗
装槽から取り出された電着塗装浴液が供給され、好まし
くは電流密度０．１〜５Ａ／ｄｍ2 にて通電することに
よりアニオン交換膜を透過してＣＨ3 ＣＯＯ- などの酸
根、カチオン交換膜を透過して鉄、亜鉛、鉛等の金属イ
オンが濃縮室に濃縮され、濃縮液として電気透析槽から
排出される。ＣＨ3 ＣＯＯ- などの酸根や亜鉛、鉄、鉛
等の金属イオンの可及的多くの量が除去された電気透析
槽の希釈液は、再び電着塗装槽に循環される。[0011] The electrodialysis tank is preferably a filter press type device assembled by tightening the whole. Cation exchange membranes and anion exchange membranes are alternately arranged between the anode and the cathode of the electrodialysis tank, and the diluting chamber is supplied with the electrocoat bath solution taken out of the electrocoat tank, and preferably has a current density of 0. by energizing at 1-5A / dm 2 anion exchange membrane through the CH 3 COO - acid, such as roots, iron passes through the cation exchange membrane, zinc, metal ions such as lead are concentrated concentrating compartment, It is discharged from the electrodialysis tank as a concentrate. CH 3 COO - acid radical or zinc, such as iron, dilutions of the electrodialysis bath as much as possible greater amount has been removed metal ions such as lead, is circulated again to electrodeposition coating bath.

【００１２】電気透析槽で使用されるカチオン交換膜と
しては、強酸性の均質膜又は均質膜が好ましく、またア
ニオン交換膜としては強塩基性の均質膜又は均質膜が好
ましい。The cation exchange membrane used in the electrodialysis tank is preferably a strongly acidic homogeneous membrane or homogeneous membrane, and the anion exchange membrane is preferably a strongly basic homogeneous membrane or homogeneous membrane.

【００１３】電気透析槽のカチオン交換膜として、金属
イオンを優先的に通し、塗料成分であるポリアミノ樹脂
や顔料を通さないような選択透過膜を使用してもよい。
そのような選択透過膜としては、カチオン交換膜の表面
にエチレンジアミンのポリマ−層を形成した膜や、さら
にカチオン交換膜とアニオン交換膜を張り合せた両性の
イオン交換膜が使用される。As the cation exchange membrane of the electrodialysis tank, a permselective membrane which allows metal ions to pass through preferentially and does not allow polyamino resin or pigment which is a coating component to pass therethrough may be used.
As such a permselective membrane, a membrane in which a polymer layer of ethylenediamine is formed on the surface of a cation exchange membrane, or an amphoteric ion exchange membrane in which a cation exchange membrane and an anion exchange membrane are further laminated are used.

【００１４】また、電着塗装槽から一部取り出された電
着塗装浴液を限外濾過装置（ＵＦ）で塗料成分の樹脂や
顔料を分離した後、電気透析槽に供給してもよい。この
ように塗料中の樹脂や顔料を予め分離除去した状態で電
気透析槽に供給すると、電気透析槽における酸及び／又
は金属イオンの除去効率が向上する。限外濾過装置（Ｕ
Ｆ）のフィルタでは、塗料中の樹脂や顔料を分離するた
めに０．１ミクロン以下、好ましくは０．０１ミクロン
以下の粒子を通過させるようにするのが好ましい。限外
濾過装置（ＵＦ）で分離除去された塗料中の塗料成分で
ある樹脂や顔料は電着塗装槽に戻される。Further, the electrodeposition bath liquid partially removed from the electrodeposition coating tank may be supplied to an electrodialysis tank after the resin or pigment of the coating component is separated by an ultrafiltration device (UF). When the resin and pigment in the paint are supplied to the electrodialysis tank in a state of being separated and removed in advance, the efficiency of removing the acid and / or metal ion in the electrodialysis tank is improved. Ultrafiltration equipment (U
In the filter of F), it is preferable to pass particles of 0.1 μm or less, preferably 0.01 μm or less in order to separate the resin and pigment in the paint. The resin and pigment, which are paint components in the paint separated and removed by the ultrafiltration device (UF), are returned to the electrodeposition coating tank.

【００１５】かくして、電気透析槽では電着塗装浴液に
含有される酸及び金属イオンの可及的多くの量が除去さ
れた後、これを電着塗装槽に循環される。しかし多くの
場合、電着塗装浴液に含有される金属イオンは、酸に比
べて少ないので、電気透析槽では金属イオンの実質的全
量を除き、一方酸は金属イオンの除去に相当する通電量
に応じた量のみを除去することもできる。かかる場合、
電着塗装浴液中に残存する酸をつぶすために、それに相
当する量の塗料成分が補給される。このようにした場
合、電気透析槽の負荷を小さくできかつ、酸の全量を除
去した場合に比べて電気透析槽の濃縮室から排出される
酸含有廃棄物を少なくすることができ、効果的なカチオ
ン型電着塗装浴液の管理ができる。Thus, in the electrodialysis tank, the acid and metal ions contained in the electrocoat bath are removed as much as possible and then circulated to the electrocoat tank. However, in many cases, the metal ion contained in the electrodeposition bath solution is smaller than the acid, so that in the electrodialysis tank, substantially all of the metal ion is removed, while the acid is the amount of electricity corresponding to the removal of the metal ion. Can be removed. In such cases,
In order to destroy the acid remaining in the electrodeposition bath solution, a corresponding amount of the paint component is replenished. In this case, the load on the electrodialysis tank can be reduced, and the acid-containing waste discharged from the enrichment chamber of the electrodialysis tank can be reduced as compared with the case where the entire amount of the acid is removed. Can manage the cation type electrodeposition bath solution.

【００１６】更に、本発明では、カチオン型電着塗装浴
液に含まれる鉄、鉛、ニッケル等の金属イオンが電着塗
装槽内の裸陽極の近傍にて酸化され、不溶性の金属酸化
物に変化することにより、電気透析による金属イオンの
除去を不能にするだけでなく、被塗装物への塗膜の品質
を低下させる場合がある。これを防止するため本発明で
は電着塗装槽内の電着塗装浴液に還元剤を好ましくは
０．０１〜０．０５当量／リットル存在させる。過度の
還元剤の存在は、被塗装物への塗膜の品質を低下させる
ので好ましくない。Further, in the present invention, metal ions such as iron, lead and nickel contained in the cation-type electrodeposition coating bath are oxidized in the vicinity of the bare anode in the electrodeposition coating tank to form an insoluble metal oxide. The change may not only make it impossible to remove metal ions by electrodialysis, but also reduce the quality of the coating film on the object to be coated. In order to prevent this, in the present invention, the reducing agent is preferably present in the electrodeposition coating bath in the electrodeposition coating bath in an amount of 0.01 to 0.05 equivalent / liter. Excessive presence of the reducing agent is not preferable because it deteriorates the quality of the coating film on the object to be coated.

【００１７】上記還元剤としては種々のものが使用でき
るが、被塗装物への塗膜及び電気透析への影響から好ま
しくは、酸化された場合に、それ自体が酸やＣＯ2 やＨ
2 Ｏになるアルデヒド、ケトン、酸、アルコールの使用
が好ましい。還元剤の好ましい例としてはホルムアルデ
ヒド、アセトアルデヒド、蟻酸が挙げられる。Although various reducing agents can be used as the reducing agent, it is preferable that the reducing agent itself be acid, CO 2 or H 2 when it is oxidized because of its influence on the coating film on the object to be coated and electrodialysis.
The use of aldehydes, ketones, acids, and alcohols that become 2 O is preferred. Preferred examples of the reducing agent include formaldehyde, acetaldehyde and formic acid.

【００１８】本発明において、カチオン型電着塗料とし
て、酸として蟻酸を中和剤とする場合が極めて効果的で
ある。蟻酸は、金属イオンの還元剤としても作用するの
で、金属イオンの酸化が防止され、電気透析により金属
イオンが効果的に除去されるので被塗装物における良好
な塗膜が得られるためである。In the present invention, it is extremely effective to use formic acid as a neutralizing agent as an acid as the cationic electrodeposition coating composition. Formic acid also acts as a reducing agent for metal ions, so that oxidation of metal ions is prevented, and metal ions are effectively removed by electrodialysis, so that a good coating film on an object to be coated can be obtained.

【００１９】かくして、本発明のカチオン型電着塗装浴
液では、電気透析により酸及び金属イオンが除去された
電着塗装浴液が循環され、好ましくは、電着塗装浴液中
のｐＨを好ましくは５〜６．５、更に好ましくは５．８
〜６．２、金属イオン濃度を好ましくは１０００ｐｐｍ
以下、更に好ましくは５００ｐｐｍ以下に保持すること
ができる。Thus, in the cationic electrodeposition coating solution of the present invention, the electrodeposition coating solution from which acid and metal ions have been removed by electrodialysis is circulated, and preferably the pH in the electrodeposition coating solution is preferably adjusted. Is 5-6.5, more preferably 5.8
~ 6.2, metal ion concentration preferably 1000 ppm
Or less, and more preferably at 500 ppm or less.

【００２０】[0020]

【発明の実施の形態】図１は本発明の電着塗装浴液の管
理方法を説明する図で、電着塗装槽１０内には鉄系金属
陽極と、陰極としての被塗装物が配置されている。一方
電気透析槽１１内にはアニオン交換膜とカチオン交換膜
が交互に配置されている。電着塗装槽から一部取り出さ
れた電着塗装浴液１２は電気透析槽１１に送られ、ここ
で酸及び金属イオン１３が除去されたのち電着塗装浴液
１４は電着塗装槽１０へ戻される。DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a diagram for explaining a method for managing an electrodeposition coating bath solution according to the present invention. In an electrodeposition coating tank 10, an iron-based metal anode and an object to be coated as a cathode are arranged. ing. On the other hand, in the electrodialysis tank 11, anion exchange membranes and cation exchange membranes are alternately arranged. The electrodeposition bath 12 partially removed from the electrodeposition bath is sent to an electrodialysis bath 11, where the acid and metal ions 13 are removed, and then the electrodeposition bath 14 is transferred to the electrodeposition bath 10. Will be returned.

【００２１】図２の電着塗装浴液の管理方法では、電着
塗装槽１０と電気透析槽１１との間に限外濾過装置（Ｕ
Ｆ）１５が配置され、電着塗装槽から一部取り出された
電着塗装浴液１２は限外濾過装置（ＵＦ）１５へ送られ
てここで塗料成分が予め分離除去された後、電気透析槽
１１に送られ、ここで酸及び金属イオン１３が除去され
て電着塗装浴液１４は電着塗装槽１０へ戻される。限外
濾過装置（ＵＦ）１５で分離された塗料成分１６は電着
塗装槽１０へ戻される。In the method of managing the electrodeposition coating bath liquid shown in FIG. 2, an ultrafiltration device (U) is provided between the electrodeposition coating tank 10 and the electrodialysis tank 11.
F) 15 is disposed, and the electrodeposition coating solution 12 partially removed from the electrodeposition coating tank is sent to an ultrafiltration device (UF) 15 where the coating components are separated and removed in advance, and then electrodialysis. The solution is sent to the tank 11 where the acid and the metal ions 13 are removed, and the electrodeposition bath solution 14 is returned to the electrodeposition tank 10. The paint component 16 separated by the ultrafiltration device (UF) 15 is returned to the electrodeposition coating tank 10.

【００２２】[0022]

【実施例】【Example】

【００２３】＜実施例１＞カチオン型電着塗装槽から取
り出したカチオン型電着塗料（日本ペイント製ＰＴＵ１
５００）２００ｇ／リットル、酢酸３ｇ／リットル、鉛
イオン０．５ｇ／リットル、鉄イオン０．５ｇ／リット
ルの組成を有するような電着塗装浴液を電気透析槽（旭
硝子製Ｄｕ−Ｏ型電気透析槽）の希釈室に供給した。一
方、電気透析槽の希釈室からの排出液は電着塗装槽に戻
した。電気透析槽の濃縮室、電極室にはそれぞれ２ｇ／
リットルの酢酸１リットルを、１０ｇ／リットルの硫酸
ナトリウム水溶液を循環した。電気透析槽の有効膜面積
は１．７ｄｍ2 で、膜対数は希釈室が１０対、濃縮室が
１１対である。アニオン交換膜として旭硝子製強塩基性
アニオン交換膜セレミオンＡＭＶ、カチオン交換膜とし
て旭硝子製強酸性カチオン交換膜セレミオンＣＭＶを使
用した。<Example 1> A cationic electrodeposition paint (PTU1 manufactured by Nippon Paint Co., Ltd.) taken out of a cationic electrodeposition coating tank was used.
500) An electrodialysis bath having a composition of 200 g / L, acetic acid 3 g / L, lead ion 0.5 g / L, and iron ion 0.5 g / L was electrodialyzed (Du-O type electrodialysis manufactured by Asahi Glass Co., Ltd.). Tank). On the other hand, the effluent from the dilution chamber of the electrodialysis tank was returned to the electrodeposition coating tank. 2g /
One liter of acetic acid was circulated through a 10 g / liter aqueous solution of sodium sulfate. The effective membrane area of the electrodialysis tank is 1.7 dm 2 , and the number of membrane pairs is 10 in the dilution chamber and 11 in the concentration chamber. A strong basic anion exchange membrane Selemion AMV manufactured by Asahi Glass was used as the anion exchange membrane, and a strongly acidic cation exchange membrane Selemion CMV manufactured by Asahi Glass was used as the cation exchange membrane.

【００２４】０．０５Ａの電流を電気透析槽に通電し、
１時間通電後濃縮液中の酢酸イオン濃度を測定した結
果、２．７２ｇ／リットルに増加し電流効率は６５％で
あった。また濃縮液中に移動した亜鉛イオンの濃度は
０．０６ｇ／リットル、鉄イオンの濃度は０．０２ｇ／
リットルで希釈液中の金属イオンが除去されていること
が確認できた。しかし塗料成分のアミンも濃縮液中に２
０ｍｇ／リットル存在することが確認できた。An electric current of 0.05 A is supplied to the electrodialysis tank,
After energizing for 1 hour, the concentration of acetate ions in the concentrated solution was measured. As a result, the concentration increased to 2.72 g / liter, and the current efficiency was 65%. The concentration of zinc ions transferred into the concentrate was 0.06 g / liter, and the concentration of iron ions was 0.02 g / liter.
It was confirmed that the metal ions in the diluent were removed in liter. However, the amine of the paint component also contains 2
It was confirmed that 0 mg / liter was present.

【００２５】＜実施例２＞実施例１における電気透析槽
におけるカチオン交換膜として旭硝子製強酸性カチオン
交換膜セレミオンＣＭＶをエチレンジアミンのポリアミ
ンで表面処理した膜を使用した他は実施例１と同様に実
施した。１時間通電後濃縮液中の酢酸イオン濃度を測定
した結果、２．８４ｇ／リットルで、酢酸の除去の電流
効率は７５％に上昇したが、濃縮液中に移動した亜鉛イ
オン濃度は０．４ｇ／リットル、鉄イオン濃度は０．０
１ｇ／リットルで実施例１に比べ除去率は若干低下し
た。しかし濃縮液中に漏洩した塗料成分であるアミン
は、濃縮液中で５ｍｇ／リットル以下であり、塗装成分
が漏れにくいことが確認できた。<Example 2> The same procedure as in Example 1 was carried out except that a membrane obtained by subjecting a strong acid cation exchange membrane Selemion CMV manufactured by Asahi Glass to surface treatment with ethylenediamine polyamine was used as the cation exchange membrane in the electrodialysis tank in Example 1. did. After energizing for 1 hour, the concentration of acetate ions in the concentrated solution was measured. As a result, the current efficiency for removing acetic acid was increased to 75% at 2.84 g / liter, but the concentration of zinc ions transferred into the concentrated solution was 0.4 g. / Liter, iron ion concentration is 0.0
At 1 g / liter, the removal rate was slightly lower than in Example 1. However, the amount of amine, which is a coating component leaked into the concentrated solution, was 5 mg / liter or less in the concentrated solution, and it was confirmed that the coating component was hard to leak.

【００２６】＜実施例３＞液量１０リットルの試験用の
電着塗装槽を用意しこの電着塗装槽に実施例１と同じカ
チオン型電着塗料であるが還元剤であるホルムアルデヒ
ド１ｇ／リットルを添加した電着液を収容し、有効通電
面積１ｄｍ2 のチタン基材にタンタルとインジウムの酸
化物で塗布した陽極と、同じく有効通電面積１ｄｍ2 の
鉄板を１０枚櫛状に溶接した陰極を取り付けた。同様な
陰極を６組用意し、通電中に６分毎に新しいものと取り
替えた。塗料が沈殿しないように電着液を攪拌し直流電
流を０．５Ａ通電した。１０分毎に陰極を取り替え、１
時間後の電着液の組成を分析した。Example 3 An electrodeposition coating tank for test having a liquid volume of 10 liters was prepared. In this electrodeposition coating tank, the same cationic electrodeposition coating as in Example 1, but formaldehyde as a reducing agent, 1 g / liter, was used. containing the added electrodeposition solution, and an anode coated with an oxide of tantalum and indium enable energization titanium substrate area 1 dm 2, the cathode is welded also the effective energization area 1 dm 2 of the iron plate 10 sheets comb Attached. Six sets of similar cathodes were prepared and replaced with new ones every 6 minutes during energization. The electrodeposition liquid was stirred and a direct current of 0.5 A was applied so that the paint did not precipitate. Replace the cathode every 10 minutes, 1
The composition of the electrodeposition solution after the time was analyzed.

【００２７】その結果、電着塗料中に含まれる顔料であ
る鉛は陽極で鉛イオンに酸化されることなく、浴液中の
鉛イオン量は０．５ｇ／リットルと同一濃度を有するこ
とが確認できた。As a result, it was confirmed that the lead contained in the electrodeposition paint was not oxidized to lead ions at the anode, and the amount of lead ions in the bath had the same concentration as 0.5 g / liter. did it.

【００２８】[0028]

【発明の効果】本発明は、電着塗装浴液の一部を電着塗
装槽の外部に取り出し、電気透析槽により酸及び金属イ
オンを除去するので、電着塗装槽を小型にでき電着塗装
浴液も少なくできる。また隔膜が電着塗装槽内にないの
で電着塗装槽の設計が容易であり、被塗装物の出し入れ
に伴い隔膜を破損することもない。さらに隔膜による酸
の除去電流効率と被塗装物への塗料の電着電流効率との
差を考慮する必要がないことも電着塗装槽の設計を容易
にする。According to the present invention, a part of the electrodeposition coating solution is taken out of the electrodeposition coating tank and the acid and metal ions are removed by the electrodialysis tank. The coating solution can be reduced. Further, since the diaphragm is not provided in the electrodeposition coating tank, the design of the electrodeposition coating tank is easy, and the diaphragm is not damaged when the object to be coated is taken in and out. Further, it is not necessary to consider the difference between the current removal efficiency of the acid by the diaphragm and the current efficiency of the electrodeposition of the paint on the object to be coated, which facilitates the design of the electrodeposition coating tank.

【００２９】また電気透析槽において、金属イオンは通
すが、塗料成分を通さない選択透過膜を使用することに
より塗料成分を回収し、電着塗装槽へ戻すことができ
る。In the electrodialysis tank, the paint components can be recovered and returned to the electrodeposition coating tank by using a permselective membrane that allows metal ions to pass through but does not pass the paint components.

【００３０】さらに電着塗装槽外に取り出した電着塗装
浴液を限外濾過装置で濾過した後、電気透析槽に供給す
ることにより、塗料成分を回収し電着塗装槽へ戻すこと
ができると共に、塗料成分を予め分離することにより電
気透析槽の負担を軽減し、酸及び／又は金属イオンの除
去効率を向上させることができる。Further, the electrodeposition coating bath liquid taken out of the electrodeposition coating tank is filtered by an ultrafiltration device and then supplied to an electrodialysis tank, whereby the paint components can be recovered and returned to the electrodeposition coating tank. At the same time, by separating the paint components in advance, the load on the electrodialysis tank can be reduced, and the removal efficiency of acid and / or metal ions can be improved.

【００３１】また、電気透析槽では酸を分離除去せずに
金属イオンだけを分離して、酸の増加量に相当する被塗
装物への電着塗装で消費された塗料成分を電着塗装槽に
補給するようにすると分離した酸の処理や補給が必要が
なく、効率的なカチオン型電着塗装浴液の管理ができ
る。In the electrodialysis tank, only metal ions are separated without separating and removing the acid, and the paint components consumed in the electrodeposition coating on the object to be coated corresponding to the increased amount of the acid are applied to the electrodeposition coating tank. When the replenishment is carried out, there is no need to treat or replenish the separated acid, and it is possible to efficiently manage the cationic electrodeposition coating bath.

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

【図１】本発明によるカチオン型電着塗装浴液の管理方
法を説明する図。FIG. 1 is a diagram illustrating a method for managing a cationic electrodeposition coating solution according to the present invention.

【図２】本発明によるカチオン型電着塗装浴液の別の管
理方法を説明する図。FIG. 2 is a view for explaining another method of managing a cationic electrodeposition coating solution according to the present invention.

【図３】従来のカチオン型電着塗装装置FIG. 3 shows a conventional cationic electrodeposition coating apparatus.

【符号の説明】[Explanation of symbols]

１０ 電着塗装槽 １１ 電気透析槽 １５ 限外濾過装置 10 Electrocoating tank 11 Electrodialysis tank 15 Ultrafiltration device

Claims (6)

【特許請求の範囲】[Claims] 【請求項１】鉄系金属陽極を用いた電着塗装槽内におい
て行われるカチオン型電着塗装において、電着塗装浴液
の一部を電着塗装槽から取り出し、イオン交換膜を組み
込んだ電気透析槽に導入して電気透析することにより該
電着塗装浴液中に含まれる酸根及び金属イオンを除去し
た後、電着塗装槽に循環することを特徴とするカチオン
型電着塗装浴液の管理方法。In a cationic electrodeposition coating performed in an electrodeposition coating tank using an iron-based metal anode, a part of an electrodeposition coating bath solution is taken out of the electrodeposition coating tank and an ion exchange membrane is incorporated therein. After removing acid radicals and metal ions contained in the electrodeposition coating bath by introducing it into a dialysis tank and performing electrodialysis, a cationic electrodeposition coating bath characterized by being circulated to the electrodeposition coating tank. Management method. 【請求項２】電着塗装浴液に含まれるカチオン型電着塗
料が蟻酸を中和剤とする塗料である請求項１に記載のカ
チオン型電着塗装浴液の管理方法。2. The method according to claim 1, wherein the cationic electrodeposition coating solution contained in the electrodeposition coating solution is a coating material containing formic acid as a neutralizing agent. 【請求項３】電着塗装槽外に取り出した電着塗装浴液を
０．１ミクロン以下の限外濾過装置で濾過して塗料成分
を分離除去後、電気透析槽の希釈室に供給する請求項１
又は２に記載のカチオン型電着塗装浴液の管理方法。3. An electrocoating bath solution taken out of the electrocoating tank is filtered with an ultrafiltration device of 0.1 μm or less to separate and remove coating components, and then supplied to a dilution chamber of the electrodialysis tank. Item 1
Or the method for managing a cationic electrodeposition coating solution according to 2. 【請求項４】電気透析槽がカチオン交換膜及びアニオン
交換膜を有し、カチオン交換膜が塗料成分に比較して金
属イオンを選択的に通過させる選択透過膜である請求項
１〜３のいづれか一つに記載のカチオン型電着塗装浴液
の管理方法。4. The electrodialyzer has a cation exchange membrane and an anion exchange membrane, and the cation exchange membrane is a permselective membrane that selectively allows metal ions to pass therethrough as compared with paint components. A method for managing a cationic electrodeposition coating solution according to one aspect. 【請求項５】電着塗装浴液に蟻酸、ホルムアルデヒド及
びアセトアルデヒドから選ばれる少なくとも一つの還元
剤を存在せしめる請求項１〜４のいづれか一つに記載の
カチオン型電着塗装浴液の管理方法。5. The method according to claim 1, wherein at least one reducing agent selected from formic acid, formaldehyde and acetaldehyde is present in the electrodeposition coating solution. 【請求項６】電気透析槽では、電着塗装浴液中の金属イ
オンの実質的全量を除去し、残存する酸根に相当する当
量の塗料成分を電着塗装浴液に補給する請求項１〜５の
いづれか一つに記載のカチオン型電着塗装浴液の管理方
法。6. The electrodialysis tank according to claim 1, wherein substantially all of the metal ions in the electrodeposition coating solution are removed, and an equivalent amount of paint components corresponding to the remaining acid radicals is supplied to the electrodeposition solution. 5. The method for managing a cationic electrodeposition coating solution according to any one of the items 5).
JP19136796A 1996-07-02 1996-07-02 Management method for cation type electrodeposition coating bath solution Pending JPH1018094A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP19136796A JPH1018094A (en) 1996-07-02 1996-07-02 Management method for cation type electrodeposition coating bath solution

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP19136796A JPH1018094A (en) 1996-07-02 1996-07-02 Management method for cation type electrodeposition coating bath solution

Publications (1)

Publication Number Publication Date
JPH1018094A true JPH1018094A (en) 1998-01-20

Family

ID=16273411

Family Applications (1)

Application Number Title Priority Date Filing Date
JP19136796A Pending JPH1018094A (en) 1996-07-02 1996-07-02 Management method for cation type electrodeposition coating bath solution

Country Status (1)

Country Link
JP (1) JPH1018094A (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE10132349A1 (en) * 2001-07-04 2003-01-30 Eisenmann Foerdertech Vehicle bodywork electrophoretic painting, controls acid removal by dialysis independently, such that anolyte acid can be re-used

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE10132349A1 (en) * 2001-07-04 2003-01-30 Eisenmann Foerdertech Vehicle bodywork electrophoretic painting, controls acid removal by dialysis independently, such that anolyte acid can be re-used
DE10132349B4 (en) * 2001-07-04 2006-08-17 Eisenmann Maschinenbau Gmbh & Co. Kg Method and plant for the cataphoretic dip painting of objects

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