JP6369095B2 - Method for inhibiting corrosion of copper-based member and corrosion inhibitor - Google Patents
Method for inhibiting corrosion of copper-based member and corrosion inhibitor Download PDFInfo
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Description
本発明は、水に接した銅系部材の腐食抑制技術に関する。詳しくは、冷却水系などの水系に接する銅管等の銅系部材に対し、薬剤を用いて腐食を抑制する技術に関する。 The present invention relates to a technique for inhibiting corrosion of a copper-based member in contact with water. More specifically, the present invention relates to a technique for suppressing corrosion using a chemical agent for a copper-based member such as a copper pipe in contact with an aqueous system such as a cooling water system.
銅は熱伝導性に優れる特性を有し、空調機器や熱交換器などの伝熱管などに広く使用されているが、これらの水系に接する銅系部材には腐食の問題がある。特に、最近の機器は高効率化が進んでおり、熱交換器に用いられる銅管の肉厚が非常に薄くなっていることから、腐食の発生は銅管の貫通漏洩につながる危険性が高い。よって、銅系部材に腐食を発生させないこと、発生した腐食を進行させないことが、機器の安定稼動、長寿命化に不可欠である。 Copper has a characteristic of excellent thermal conductivity, and is widely used for heat transfer tubes such as air conditioners and heat exchangers. However, these copper-based members in contact with water systems have a problem of corrosion. In particular, the efficiency of recent equipment is increasing, and the thickness of copper pipes used in heat exchangers is extremely thin. Therefore, the occurrence of corrosion has a high risk of lead-through leakage of copper pipes. . Therefore, it is indispensable for stable operation and long life of the equipment that the copper-based member does not corrode and does not proceed with the generated corrosion.
一般に、腐食反応は金属の溶出反応（アノード反応）と酸化剤の還元反応（カソード反応）が対になって進行する。例えば、冷却水のようなｐＨ中性から弱アルカリ性の環境では、水中の溶存酸素が酸化剤としてカソード反応の担い手になる。 In general, the corrosion reaction proceeds by a pair of metal elution reaction (anode reaction) and oxidant reduction reaction (cathode reaction). For example, in a pH neutral to weakly alkaline environment such as cooling water, dissolved oxygen in the water becomes a catalyst for the cathode reaction as an oxidizing agent.
従来、水系に接する銅系部材の腐食を抑制するために、ベンゾトリアゾール、トリルトリアゾール、メルカプトベンゾチアゾールといったアゾール系の銅用防食剤を水系に添加する水処理が行われている（例えば、特許文献１，２）。冷却水系などの水系に、これらのアゾール系銅用防食剤を添加することにより、水系に接する銅系部材に対して優れた腐食抑制効果を発揮することが知られており、広く適用されている。 Conventionally, in order to suppress corrosion of a copper-based member in contact with an aqueous system, water treatment in which an azole-based anticorrosive agent for copper such as benzotriazole, tolyltriazole, or mercaptobenzothiazole is added to the aqueous system has been performed (for example, Patent Documents). 1, 2). It is known that by adding these azole copper anticorrosives to an aqueous system such as a cooling water system, it exhibits an excellent corrosion-inhibiting effect on copper-based members in contact with the aqueous system, and is widely applied. .
即ち、アゾール系の銅用防食剤は、腐食反応における金属の溶出反応（アノード反応）を抑制する効果に優れており、良好な腐食抑制効果を示す。 That is, the azole-type anticorrosive agent for copper is excellent in the effect of suppressing the metal elution reaction (anode reaction) in the corrosion reaction, and exhibits a good corrosion-inhibiting effect.
従来、安全性の高い冷却水処理剤を要望する食品、飲料水、医薬品の製造工場においては、米国FDA規格記載品を原料とする冷却水処理剤を使用するか、あるいは水処理剤を使用しないなどして冷却水系における銅材質の腐食障害に苦慮していた。 Conventionally, in food, drinking water, and pharmaceutical manufacturing plants that require a highly safe cooling water treatment agent, use a cooling water treatment agent that uses U.S. FDA standard products, or do not use a water treatment agent. As a result, it was difficult to corrode copper materials in the cooling water system.
本発明は、上記従来の問題を解決し、冷却水系などの水系に接する銅管等の銅系部材腐食の発生を効果的に抑制することができ、しかも安全性にも優れた腐食抑制方法及び腐食抑制剤を提供することを課題とする。 The present invention solves the above-mentioned conventional problems, can effectively suppress the occurrence of corrosion of a copper-based member such as a copper pipe in contact with an aqueous system such as a cooling water system, and also has an excellent corrosion control method and safety. It is an object to provide a corrosion inhibitor.
本発明者は上記課題を解決すべく鋭意検討を重ねた結果、特定の食品添加物が、水系に接した銅系部材の腐食抑制効果に優れることを見出した。 As a result of intensive studies to solve the above problems, the present inventor has found that a specific food additive is excellent in the corrosion-inhibiting effect of a copper-based member in contact with an aqueous system.
本発明はこのような知見に基いて達成されたものであり、本発明の銅系部材腐食抑制方法は、水系に対し、２−メチルチオベンゾチアゾール、葉酸、クエン酸、カゼインナトリウム、酢酸２−（４−メチル−５−チアゾリル）エチル、５−（２−ヒドロキシエチル）−４−メチルチアゾール、２−メチル-メチルチオピラジン、２−メチルチオチアゾール、２−エチル-メチルチオピラジン、チアゾール、ベンゾチアゾール、デヒドロ酢酸ナトリウム及びＬ−アスコルビン酸よりなる群から選ばれた少なくとも１種を添加することを特徴とするものである。 The present invention has been achieved on the basis of such knowledge, and the copper-based member corrosion inhibiting method of the present invention is based on 2-methylthiobenzothiazole, folic acid, citric acid, sodium caseinate, acetic acid 2- ( 4-methyl-5-thiazolyl) ethyl, 5- (2-hydroxyethyl) -4-methylthiazole, 2-methyl-methylthiopyrazine, 2-methylthiothiazole, 2-ethyl-methylthiopyrazine, thiazole, benzothiazole, dehydroacetic acid At least one selected from the group consisting of sodium and L-ascorbic acid is added.
本発明の銅系部材の腐食抑制剤は、２−メチルチオベンゾチアゾール、葉酸、クエン酸、カゼインナトリウム、酢酸２−（４−メチル−５−チアゾリル）エチル、５−（２−ヒドロキシエチル）−４−メチルチアゾール、２−メチル-メチルチオピラジン、２−メチルチオチアゾール、２−エチル-メチルチオピラジン、チアゾール、ベンゾチアゾール、デヒドロ酢酸ナトリウム及びＬ−アスコルビン酸よりなる群から選ばれた少なくとも１種を含むことを特徴とするものである。 Corrosion inhibitors for copper-based members of the present invention include 2-methylthiobenzothiazole, folic acid, citric acid, sodium caseinate, 2- (4-methyl-5-thiazolyl) ethyl acetate, 5- (2-hydroxyethyl) -4 -Containing at least one selected from the group consisting of methylthiazole, 2-methyl-methylthiopyrazine, 2-methylthiothiazole, 2-ethyl-methylthiopyrazine, thiazole, benzothiazole, sodium dehydroacetate and L-ascorbic acid. It is a feature.
本発明では、前記水系は食品、飲料水、医薬品等の製造工場の開放循環冷却水系であることが好ましい。 In the present invention, the water system is preferably an open circulating cooling water system of a manufacturing factory for food, drinking water, pharmaceuticals and the like.
本発明で用いる２−メチルチオベンゾチアゾール、葉酸、クエン酸、カゼインナトリウム、酢酸２−（４−メチル−５−チアゾリル）エチル、５−（２−ヒドロキシエチル）−４−メチルチアゾール、２−メチル-メチルチオピラジン、２−メチルチオチアゾール、２−エチル-メチルチオピラジン、チアゾール、ベンゾチアゾール、デヒドロ酢酸ナトリウム及びＬ−アスコルビン酸よりなる群から選ばれた少なくとも１種は、銅系部材の腐食抑制効果に優れる。また、これらの化合物は食品添加物であり、安全性に優れる。 2-methylthiobenzothiazole, folic acid, citric acid, sodium caseinate, 2- (4-methyl-5-thiazolyl) ethyl acetate, 5- (2-hydroxyethyl) -4-methylthiazole, 2-methyl- At least one selected from the group consisting of methylthiopyrazine, 2-methylthiothiazole, 2-ethyl-methylthiopyrazine, thiazole, benzothiazole, sodium dehydroacetate and L-ascorbic acid is excellent in the corrosion-inhibiting effect of the copper-based member. Moreover, these compounds are food additives and are excellent in safety.
従って、本発明によれば、食品、飲料水、医薬品等の製造工場等の水系においても、銅系部材の腐食を安全かつ効果的に抑制することができる。 Therefore, according to the present invention, corrosion of a copper-based member can be safely and effectively suppressed even in an aqueous system such as a manufacturing factory for food, drinking water, pharmaceuticals, and the like.
以下に本発明の銅系部材の腐食抑制方法及び腐食抑制剤の実施の形態を詳細に説明する。 DESCRIPTION OF EMBODIMENTS Embodiments of a method for inhibiting corrosion of a copper-based member and a corrosion inhibitor according to the present invention will be described in detail below.
本発明においては、腐食抑制剤として２−メチルチオベンゾチアゾール、葉酸、クエン酸、カゼインナトリウム、酢酸２−（４−メチル−５−チアゾリル）エチル、５−（２−ヒドロキシエチル）−４−メチルチアゾール、２−メチル-メチルチオピラジン、２−メチルチオチアゾール、２−エチル-メチルチオピラジン、チアゾール、ベンゾチアゾール、デヒドロ酢酸ナトリウム及びＬ−アスコルビン酸よりなる群から選ばれた少なくとも１種を銅系部材に接する水系に添加する。 In the present invention, 2-methylthiobenzothiazole, folic acid, citric acid, sodium caseinate, 2- (4-methyl-5-thiazolyl) ethyl acetate, 5- (2-hydroxyethyl) -4-methylthiazole as a corrosion inhibitor An aqueous system contacting at least one selected from the group consisting of 2-methyl-methylthiopyrazine, 2-methylthiothiazole, 2-ethyl-methylthiopyrazine, thiazole, benzothiazole, sodium dehydroacetate and L-ascorbic acid Add to.
これらの化合物の水系への添加濃度は、通常０．１〜２０ｍｇ／Ｌの範囲であり、好ましくは０．５〜１０ｍｇ／Ｌである。 The concentration of these compounds added to the aqueous system is usually in the range of 0.1 to 20 mg / L, preferably 0.5 to 10 mg / L.
上記化合物よりなる銅用防食剤の水系への添加方法には特に制限はないが、水溶液として水系へ添加することが好ましい。 Although there is no restriction | limiting in particular in the addition method to the aqueous system of the anticorrosive agent for copper which consists of the said compound, It is preferable to add to aqueous system as aqueous solution.
本発明においては、本発明の効果（安全性）を阻害しない範囲で、上記銅用防食剤以外の他の水処理剤を併用することが可能である。例えば、スケール防止剤としてグルタミン酸、アルギン酸ナトリウム、カラヤゴム、又はフィチン酸などを併用添加しても良い。 In the present invention, water treatment agents other than the above-described anticorrosive agent for copper can be used in combination as long as the effects (safety) of the present invention are not impaired. For example, glutamic acid, sodium alginate, karaya gum, or phytic acid may be added in combination as a scale inhibitor.
以下に実施例を挙げて本発明をより具体的に説明する。 Hereinafter, the present invention will be described more specifically with reference to examples.
［実施例１〜１３、比較例１］
ＪＩＳ Ｋ０１００「工業用水腐食試験方法」に記載された「回転法」に準拠した評価を行った。ビーカー内の試験水に、試験片１枚を取り付けた支持棒を浸漬し、試験片表面の線流速が０．５ｍ／ｓｅｃとなるよう支持棒を回転させた。試験前後の試験片の重量変化より銅の腐食速度を測定する方法で評価を行った。
[Examples 1 to 13, Comparative Example 1]
Evaluation based on "Rotation method" described in JIS K0100 "Industrial water corrosion test method" was performed. The support rod attached with one test piece was immersed in the test water in the beaker, and the support rod was rotated so that the linear flow velocity on the surface of the test piece was 0.5 m / sec. Evaluation was performed by measuring the corrosion rate of copper from the change in weight of the test piece before and after the test.
試験水、用いた薬剤、試験片、試験条件は以下の通りである。 Test water, chemicals used, test pieces, and test conditions are as follows.
＜試験水＞
水道水（栃木県野木町）の脱塩素水に１０ｗｔ％塩化ナトリウム水溶液１１ｍＬ及び１０ｗｔ％硫酸ナトリウム水溶液１１ｍＬを添加し、ＮａＯＨ又は硫酸でｐＨ８．０に調整したものを試験水とした。
<Test water>
Test water was prepared by adding 11 mL of 10 wt% sodium chloride aqueous solution and 11 mL of 10 wt% sodium sulfate aqueous solution to dechlorinated water of tap water (Nogi-machi, Tochigi Prefecture) and adjusting the pH to 8.0 with NaOH or sulfuric acid.
この試験水のカルシウム硬度及び酸消費量（ｐＨ４．８）は４０〜６０ｍｇ／ＬａｓＣａＣＯ３、塩化物イオン濃度は１０００ｍｇ／ＬａｓＣｌ−、硫酸イオン濃度は１０００ｍｇ／ＬａｓＳＯ４ ２−であった。 The calcium hardness and acid consumption (pH 4.8) of this test water were 40 to 60 mg / LasCaCO 3 , the chloride ion concentration was 1000 mg / LasCl − , and the sulfate ion concentration was 1000 mg / LasSO 4 2− .
＜薬剤＞
この試験水１．１Ｌに対し２−メチルチオベンゾチアゾール、葉酸、クエン酸、カゼインナトリウム、酢酸２−（４−メチル−５−チアゾリル）エチル、５−（２−ヒドロキシエチル）−４−メチルチアゾール、２−メチル-メチルチオピラジン、２−メチルチオチアゾール、２−エチル-メチルチオピラジン、チアゾール、ベンゾチアゾール、デヒドロ酢酸ナトリウム、又はＬ−アスコルビン酸の各１ｗｔ％水溶液を５．５ｍＬ添加した。添加後の試験水中の腐食抑制剤の濃度は５ｍｇ／Ｌである。なお、腐食抑制剤を添加しないブランクテストを比較例１とした。
<Drug>
2-methylthiobenzothiazole, folic acid, citric acid, sodium caseinate, 2- (4-methyl-5-thiazolyl) ethyl acetate, 5- (2-hydroxyethyl) -4-methylthiazole, 1.1 L of this test water, 5.5 mL of each 1 wt% aqueous solution of 2-methyl-methylthiopyrazine, 2-methylthiothiazole, 2-ethyl-methylthiopyrazine, thiazole, benzothiazole, sodium dehydroacetate, or L-ascorbic acid was added. The concentration of the corrosion inhibitor in the test water after the addition is 5 mg / L. In addition, the blank test which does not add a corrosion inhibitor was made into the comparative example 1.
＜試験片＞
長辺５０ｍｍ、短辺３０ｍｍ、厚さ１ｍｍの銅（Ｃ１２２０）製試験片（トルエンで脱脂して重量を測定する。）
<Specimen>
A test piece made of copper (C1220) having a long side of 50 mm, a short side of 30 mm, and a thickness of 1 mm (degrease with toluene and measure the weight).
＜試験条件＞
試験片を支持棒に取り付け、試験片が試験水に浸るように回転試験装置にセットし、支持棒を１４５ｓｐｍで回転させた。
<Test conditions>
The test piece was attached to a support bar, set in a rotating test apparatus so that the test piece was immersed in test water, and the support bar was rotated at 145 spm.
試験温度は４０℃、試験期間は３日間である。 The test temperature is 40 ° C. and the test period is 3 days.
３日経過後、銅製試験片の重量を測定し、腐食速度（ｍｄｄ（ｍｇ／ｄｍ２／ｄａｙ））を求め、結果を表１に示した。 After the elapse of 3 days, the weight of the copper test piece was measured, the corrosion rate (mdd (mg / dm 2 / day)) was determined, and the results are shown in Table 1.
＜考察＞
表１より、実施例１〜１３のように２−メチルチオベンゾチアゾール、葉酸、クエン酸、カゼインナトリウム、酢酸２−（４−メチル−５−チアゾリル）エチル、５−（２−ヒドロキシエチル）−４−メチルチアゾール、２−メチル-メチルチオピラジン、２−メチルチオチアゾール、２−エチル-メチルチオピラジン、チアゾール、ベンゾチアゾール、デヒドロ酢酸ナトリウム又はＬ−アスコルビン酸を水系に添加することにより、ブランク（比較例１）に比べて腐食が大きく抑制されていることが確認された。
<Discussion>
From Table 1, as in Examples 1-13, 2-methylthiobenzothiazole, folic acid, citric acid, sodium caseinate, 2- (4-methyl-5-thiazolyl) ethyl acetate, 5- (2-hydroxyethyl) -4 -By adding methylthiazole, 2-methyl-methylthiopyrazine, 2-methylthiothiazole, 2-ethyl-methylthiopyrazine, thiazole, benzothiazole, sodium dehydroacetate or L-ascorbic acid to the aqueous system (Comparative Example 1) It was confirmed that corrosion was greatly suppressed compared to.
Claims (2)
前記水系が食品、飲料水、又は医薬品の製造工場の開放循環冷却水系であることを特徴とする銅系部材の腐食抑制方法。 To water systems in contact with the copper-based member, 2-methylthio-benzothiazole, casein sodium, acetate 2- (4-methyl-5-thiazolyl) ethyl, 5- (2-hydroxyethyl) -4-methylthiazole, 2-methyl - methylthio pyrazine, 2-methylthiazole punch line azoles, and 2-ethyl - a corrosion inhibiting method for a copper-based member to add at least one selected from Mechiruchiopiraji emissions by Li Cheng group,
The method for inhibiting corrosion of a copper-based member, wherein the water system is an open circulating cooling water system of a food, drinking water, or pharmaceutical manufacturing factory.
前記水系が食品、飲料水、又は医薬品の製造工場の開放循環冷却水系である銅系部材の腐食抑制剤。 A suppressing corrosion inhibitor the corrosion of copper-based member in contact with the water-based, 2-methylthio-benzothiazole, casein sodium, acetate 2- (4-methyl-5-thiazolyl) ethyl, 5- (2-hydroxyethyl) 4-methylthiazole, 2-methyl - it includes Mechiruchiopiraji emissions by at least one member selected from Li Cheng group, - methylthio pyrazine, 2-methylthiazole punch line benzothiazole, and 2-ethyl
A corrosion inhibitor for copper-based members, wherein the water system is an open circulation cooling water system of a food, drinking water, or pharmaceutical manufacturing factory.
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| JPS5925034B2 (en) * | 1981-04-06 | 1984-06-13 | 栗田工業株式会社 | Corrosion inhibitor for copper |
| JPS6389687A (en) * | 1986-10-01 | 1988-04-20 | Japan Organo Co Ltd | Method for preventing corrosion of carbon steel, copper and copper alloy in water |
| JPH03500416A (en) * | 1988-07-29 | 1991-01-31 | エス・アール・アイ・インターナシヨナル | Cooperative corrosion inhibitors based on substituted pyridinium compounds |
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