JP5824841B2 - Method for inhibiting corrosion of copper-based parts - Google Patents
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本発明は、カルシウム硬度の低い水系、特に循環水のカルシウム硬度が低い開放循環式冷却水系に接する銅系部材の腐食を効果的に抑制する方法に関する。 The present invention relates to a method for effectively suppressing corrosion of a copper-based member in contact with an aqueous system having a low calcium hardness, in particular, an open circulation type cooling water system having a low calcium hardness of circulating water.
開放式循環冷却水系では、冷水塔における循環冷却水の蒸発及び飛散による循環冷却水のロスを補うための補給水と、循環冷却水のブロー水とのバランスを取りながら運転が行われている。循環冷却水の蒸発により、循環冷却水は徐々に濃縮される。補給水に含まれる溶存物質も濃縮するため、例えば重炭酸イオンやカルシウムイオン濃度の上昇によるスケールトラブル、塩化物イオンや硫酸イオン等の腐食性イオン濃度上昇による腐食トラブル、有機物濃度上昇によるスライムトラブルなどの障害が起こりやすくなる。そこで、冷却水の水質管理を行うとともに、スケール抑制剤、腐食抑制剤、スライム抑制剤を水系に添加する水処理が行われている。 In the open type circulating cooling water system, the operation is performed while balancing the supplementary water for compensating the loss of the circulating cooling water due to the evaporation and scattering of the circulating cooling water in the cooling tower and the blown water of the circulating cooling water. The circulating cooling water is gradually concentrated by the evaporation of the circulating cooling water. Since the dissolved substances contained in the makeup water are also concentrated, for example, scale troubles due to increased bicarbonate and calcium ion concentrations, corrosion problems due to increased corrosive ion concentrations such as chloride ions and sulfate ions, slime problems due to increased organic matter concentrations, etc. The failure is likely to occur. Therefore, water treatment is performed in which water quality is controlled and a scale inhibitor, corrosion inhibitor, and slime inhibitor are added to the water system.
従来、水系の金属の腐食抑制剤として、ホスホン酸等に代表されるリン含有化合物やカルボン酸基含有共重合体を水系に添加する水処理方法が提案されている（特許文献１，２）。 Conventionally, a water treatment method has been proposed in which a phosphorus-containing compound typified by phosphonic acid or the like or a carboxylic acid group-containing copolymer is added to an aqueous system as an aqueous metal corrosion inhibitor (Patent Documents 1 and 2).
リン含有化合物やカルボン酸基含有共重合体を水系に添加する従来の水処理は、広い水質範囲でスケール抑制や炭素鋼の腐食抑制が可能であり、スライム抑制剤と併用することにより良好な冷却水処理効果を得ることが可能である。スライム抑制剤としては、次亜塩素酸ナトリウムに代表される酸化性物質が使用される場合があるが、リン含有化合物と、カルボン酸基含有共重合体と、酸化性物質とを併用する水処理において、更にはアゾール系銅用防食剤を併用しているにもかかわらず、カルシウム硬度１００ｍｇ／Ｌ ａｓ ＣａＣＯ3未満の水系、特にカルシウム硬度５０ｍｇ／Ｌ ａｓ ＣａＣＯ3未満の水系で銅系部材の腐食を十分に抑制できない課題があった。 Conventional water treatments that add phosphorus-containing compounds and carboxylic acid group-containing copolymers to water systems can suppress scale and corrosion of carbon steel in a wide water quality range, and can be cooled well when used in combination with slime inhibitors. It is possible to obtain a water treatment effect. As a slime inhibitor, an oxidizing substance typified by sodium hypochlorite may be used, but a water treatment using a phosphorus-containing compound, a carboxylic acid group-containing copolymer, and an oxidizing substance in combination. In addition, despite the combined use of an azole copper anticorrosive agent, the corrosion of copper-based members in an aqueous system with a calcium hardness of less than 100 mg / L as CaCO 3 , particularly an aqueous system with a calcium hardness of less than 50 mg / L as CaCO 3 There was a problem that could not be sufficiently suppressed.
本発明は、カルシウム硬度の低い水系、特に循環水のカルシウム硬度が低い開放循環式冷却水系に接する銅系部材の腐食を効果的に抑制する方法を提供することを課題とする。 An object of the present invention is to provide a method for effectively suppressing corrosion of a copper-based member in contact with an aqueous system having a low calcium hardness, particularly an open circulation type cooling water system having a low calcium hardness of circulating water.
本発明者らは、カルシウム硬度１００ｍｇ／Ｌ ａｓ ＣａＣＯ3未満の水系、特にカルシウム硬度５０ｍｇ／Ｌ ａｓ ＣａＣＯ3未満の水系で、リン含有化合物と、カルボン酸基含有共重合体と、酸化性物質を併用する水処理において、銅系部材の腐食を十分に抑制できないという課題に対し検討を行った結果、酸化性物質濃度を適正なレベルに管理するとともに、アゾール系銅用防食剤を特定の濃度以上となるよう水系に添加することで、銅系部材の腐食を十分に抑制できることを見出し、本発明に到達した。 The inventors of the present invention have disclosed a phosphorus-containing compound, a carboxylic acid group-containing copolymer, and an oxidizing substance in an aqueous system having a calcium hardness of less than 100 mg / L as CaCO 3 , particularly an aqueous system having a calcium hardness of less than 50 mg / L as CaCO 3. As a result of investigating the problem that the corrosion of copper-based parts cannot be sufficiently suppressed in the combined water treatment, the oxidizing substance concentration is controlled to an appropriate level, and the azole-based anticorrosive agent for copper is above a specific concentration. As a result, it was found that the corrosion of the copper-based member can be sufficiently suppressed by adding to the aqueous system, and the present invention has been achieved.
すなわち、本発明（請求項１）の銅系部材の腐食抑制方法は、カルシウム硬度１００ｍｇ／Ｌ ａｓ ＣａＣＯ3未満の水系において、リン含有化合物と、カルボン酸基含有共重合体と、酸化性物質とを添加して、該水系に接する銅系部材の腐食を抑制する方法であって、ＤＰＤ法にて試薬添加１０秒後の発色が遊離塩素濃度０．５ｍｇ／Ｌ ａｓ Ｃｌ2以下かつ３０秒後の発色が遊離塩素濃度１ｍｇ／Ｌ ａｓ Ｃｌ2以下に相当するように、該水系の酸化性物質濃度を管理するとともに、該水系に、アゾール系銅用防食剤を、下記（１）式で算出されるアゾール系銅用防食剤必要濃度（ｍｇ／Ｌ）をＡｍｇ／Ｌとした場合において、Ａｍｇ／Ｌ〜（Ａ＋５）ｍｇ／Ｌの範囲で添加することを特徴とする。
アゾール系銅用防食剤必要濃度（ｍｇ／Ｌ）
＝Ｐ×０．２＋Ｓ×０．４＋Ｏ×１０ （１）
Ｐ：リン含有化合物濃度（ｍｇ／Ｌ ａｓ ＰＯ4 3-）
Ｓ：カルボン酸基含有共重合体濃度（ｍｇ／Ｌ ａｓ 固形分）
Ｏ：酸化性物質濃度※（ｍｇ／Ｌ ａｓ Ｃｌ2）
※ＤＰＤ法の試薬添加１０秒後の発色に相当する遊離塩素濃度
That is, the method for inhibiting corrosion of a copper-based member of the present invention (Claim 1) includes a phosphorus-containing compound, a carboxylic acid group-containing copolymer, and an oxidizing substance in an aqueous system having a calcium hardness of less than 100 mg / L as CaCO 3. To prevent corrosion of the copper-based member in contact with the aqueous system, and the color development 10 seconds after addition of the reagent by the DPD method is less than 0.5 mg / L as Cl 2 and 30 seconds after the free chlorine concentration. The concentration of the oxidizing agent in the aqueous system is controlled so that the color development of the aqueous solution corresponds to a free chlorine concentration of 1 mg / L as Cl 2 or less, and the azole-based anticorrosive agent for copper is calculated in the aqueous system using the following formula (1). When the required concentration (mg / L) of an azole copper anticorrosive agent is Amg / L, it is added in the range of Amg / L to (A + 5) mg / L.
Required concentration of anticorrosive for azole copper (mg / L)
= P × 0.2 + S × 0.4 + O × 10 (1)
P: Phosphorus-containing compound concentration (mg / L as PO 4 3− )
S: Concentration of carboxylic acid group-containing copolymer (mg / L as solid content)
O: Oxidizing substance concentration * (mg / L as Cl 2 )
* Free chlorine concentration corresponding to color development 10 seconds after addition of reagent in DPD method
請求項２の銅系部材の腐食抑制方法は、請求項１において、前記水系のカルシウム硬度が５０ｍｇ／Ｌ ａｓ ＣａＣＯ3未満であることを特徴とする。 The method for inhibiting corrosion of a copper-based member according to claim 2 is characterized in that, in claim 1, the aqueous calcium hardness is less than 50 mg / L as CaCO 3 .
請求項３の銅系部材の腐食抑制方法は、請求項１又は２において、前記リン含有化合物として、２−ホスホノブタン−１，２，４−トリカルボン酸を、カルボン酸基含有共重合体としてマレイン酸とイソブチレンとの共重合体及び／又はアクリル酸と２−アクリルアミド−２−メチルプロパンスルホン酸の共重合体を、アゾール系銅用防食剤としてベンゾトリアゾールを用いることを特徴とする。 The method for inhibiting corrosion of a copper-based member according to claim 3 is the method according to claim 1 or 2, wherein 2-phosphonobutane-1,2,4-tricarboxylic acid is used as the phosphorus-containing compound, and maleic acid is used as the carboxylic acid group-containing copolymer. A copolymer of styrene and isobutylene and / or a copolymer of acrylic acid and 2-acrylamido-2-methylpropane sulfonic acid is used as an azole copper anticorrosive, and benzotriazole is used.
請求項４の銅系部材の腐食抑制方法は、請求項１ないし３のいずれか１項において、前記酸化性物質としてクロラミン化合物を用いることを特徴とする。 The method for inhibiting corrosion of a copper-based member according to claim 4 is characterized in that, in any one of claims 1 to 3, a chloramine compound is used as the oxidizing substance.
請求項５の銅系部材の腐食抑制方法は、請求項４において、前記クロラミン化合物が塩素化スルアファミン酸及び／又はその塩であることを特徴とする。 The method for inhibiting corrosion of a copper-based member according to claim 5 is characterized in that, in claim 4, the chloramine compound is chlorinated sulfafamic acid and / or a salt thereof.
本発明の銅系部材の腐食抑制方法によれば、例えば純水などカルシウム硬度が極めて低い水を補給水とする開放循環冷却水系において、銅系部材の腐食を抑制しつつ、酸化性物質よりなるスライム抑制剤による確実なスライム抑制効果を得ることで良好な冷却水処理効果を得ることが可能となる。その結果、熱交換器の伝熱効率低下の抑制による省エネルギーへの貢献や、配管・機器類の長寿命化により、環境に対し寄与することが可能となる。 According to the copper member corrosion inhibiting method of the present invention, for example, in an open circulating cooling water system using water with extremely low calcium hardness such as pure water as makeup water, the copper member is made of an oxidizing substance while inhibiting corrosion of the copper member. A good cooling water treatment effect can be obtained by obtaining a reliable slime suppression effect by the slime inhibitor. As a result, it is possible to contribute to the environment by contributing to energy savings by suppressing a decrease in heat transfer efficiency of the heat exchanger and extending the life of piping and equipment.
以下に本発明の銅系部材の腐食抑制方法の実施の形態を詳細に説明する。 Embodiments of the copper member corrosion inhibiting method of the present invention will be described in detail below.
本発明の銅系部材の腐食抑制方法は、カルシウム硬度の低い水系、特に循環水のカルシウム硬度が低い開放循環式冷却水系に接する銅系部材の腐食を抑制する水処理処理方法に関するものであり、カルシウム硬度１００ｍｇ／Ｌ ａｓ ＣａＣＯ3未満の水系において、リン含有化合物と、カルボン酸基含有共重合体と、酸化性物質とを添加して、該水系に接する銅系部材の腐食を抑制する方法であって、ＤＰＤ法にて試薬添加１０秒後の発色が遊離塩素濃度０．５ｍｇ／Ｌ ａｓ Ｃｌ2以下かつ３０秒後の発色が遊離塩素濃度１ｍｇ／Ｌ ａｓ Ｃｌ2以下に相当するように、該水系の酸化性物質濃度を管理するとともに、該水系に、アゾール系銅用防食剤を、下記（１）式で算出されるアゾール系銅用防食剤必要濃度（ｍｇ／Ｌ）以上に添加することを特徴とする。
アゾール系銅用防食剤必要濃度（ｍｇ／Ｌ）
＝Ｐ×０．２＋Ｓ×０．４＋Ｏ×１０ （１）
Ｐ：リン含有化合物濃度（ｍｇ／Ｌ ａｓ ＰＯ4 3-）
Ｓ：カルボン酸基含有共重合体濃度（ｍｇ／Ｌ ａｓ 固形分）
Ｏ：酸化性物質濃度※（ｍｇ／Ｌ ａｓ Ｃｌ2）
※ＤＰＤ法の試薬添加１０秒後の発色に相当する遊離塩素濃度
The method for inhibiting corrosion of a copper-based member of the present invention relates to a water treatment method for inhibiting corrosion of a copper-based member in contact with an aqueous system having a low calcium hardness, particularly an open circulation cooling water system having a low calcium hardness of circulating water, In an aqueous system having a calcium hardness of less than 100 mg / L as CaCO 3 , a method of suppressing corrosion of a copper-based member in contact with the aqueous system by adding a phosphorus-containing compound, a carboxylic acid group-containing copolymer, and an oxidizing substance. In the DPD method, the color development 10 seconds after addition of the reagent corresponds to a free chlorine concentration of 0.5 mg / L as Cl 2 or less and the color development after 30 seconds corresponds to a free chlorine concentration of 1 mg / L as Cl 2 or less. In addition to controlling the concentration of the aqueous oxidizing substance, the azole copper anticorrosive agent is added to the aqueous system at a concentration higher than the required concentration (mg / L) of the azole copper anticorrosive agent calculated by the following formula (1). And wherein the door.
Required concentration of anticorrosive for azole copper (mg / L)
= P × 0.2 + S × 0.4 + O × 10 (1)
P: Phosphorus-containing compound concentration (mg / L as PO 4 3− )
S: Concentration of carboxylic acid group-containing copolymer (mg / L as solid content)
O: Oxidizing substance concentration * (mg / L as Cl 2 )
* Free chlorine concentration corresponding to color development 10 seconds after addition of reagent in DPD method
本発明において、用いるリン含有化合物としては、特に制限はないが、次に示す化合物及びその塩が例示される。すなわち、正リン酸、ピロリン酸、トリポリリン酸、ヘキサメタリン酸、１−ヒドロキシエチリデン−１，１−ジホスホン酸、２−ホスホノブタン−１，２，４−トリカルボン酸、ヒドロキシホスホノ酢酸、ホスホノポリマレイン酸、ビス−ポリ（２−カルボキシエチル）ホスフィン酸及びこれらのナトリウム塩、カリウム塩等のアルカリ金属塩などが挙げられ、その１種又は２種以上が用いられる。
水系に添加するリン含有化合物の濃度としては１〜２０ｍｇ／Ｌ ａｓ ＰＯ4 3-、特に２．５〜１０ｍｇ／Ｌ ａｓ ＰＯ4 3-の範囲となるように添加することが望ましい。
In the present invention, the phosphorus-containing compound to be used is not particularly limited, but the following compounds and salts thereof are exemplified. That is, orthophosphoric acid, pyrophosphoric acid, tripolyphosphoric acid, hexametaphosphoric acid, 1-hydroxyethylidene-1,1-diphosphonic acid, 2-phosphonobutane-1,2,4-tricarboxylic acid, hydroxyphosphonoacetic acid, phosphonopolymaleic acid , Bis-poly (2-carboxyethyl) phosphinic acid and alkali metal salts such as sodium salt and potassium salt thereof, and one or more of them are used.
The concentration of the phosphorus-containing compound added to the aqueous system is desirably 1 to 20 mg / L as PO 4 3− , particularly 2.5 to 10 mg / L as PO 4 3− .
本発明において用いるカルボン酸基含有共重合体としては、マレイン酸系重合体、（メタ）アクリル酸系重合体が挙げられる。このようなカルボン酸基含有共重合体としては、ホモマレイン酸重合体、ホモ（メタ）アクリル酸重合体、マレイン酸又は（メタ）アクリルと共重合可能な不飽和単量体との共重合体などが挙げられる。マレイン酸又は（メタ）アクリルと共重合可能な不飽和単量体としては、２−アクリルアミド−２−メチルプロパンスルホン酸、２−ヒドロキシ−３−アリロキシ−１−プロパンスルホン酸、スチレンスルホン酸、ビニルスルホン酸、アクリルアミド、エチレン、プロピレン、イソプロピレン、ブチレン、イソブチレン、ヘキセン、２−エチルヘキセン、ペンテン、イソペンテン、オクテン、イソオクテン、ビニルアルコール、ビニルメチルエーテル、ビニルエチルエーテルなどが挙げられ、その１種又は２種以上が用いられる。カルボン酸基含有共重合体は、１種を単独で用いてもよく、２種以上を併用してもよい。
水系に添加するカルボン酸基含有共重合体の濃度としては３〜２０ｍｇ／Ｌ ａｓ 固形分、特に５〜１５ｍｇ／Ｌ ａｓ 固形分の範囲となるように添加することが望ましい。
Examples of the carboxylic acid group-containing copolymer used in the present invention include a maleic acid polymer and a (meth) acrylic acid polymer. Such carboxylic acid group-containing copolymers include homomaleic acid polymers, homo (meth) acrylic acid polymers, copolymers with unsaturated monomers copolymerizable with maleic acid or (meth) acrylic, etc. Is mentioned. Examples of unsaturated monomers copolymerizable with maleic acid or (meth) acrylic include 2-acrylamido-2-methylpropanesulfonic acid, 2-hydroxy-3-allyloxy-1-propanesulfonic acid, styrenesulfonic acid, vinyl Examples thereof include sulfonic acid, acrylamide, ethylene, propylene, isopropylene, butylene, isobutylene, hexene, 2-ethylhexene, pentene, isopentene, octene, isooctene, vinyl alcohol, vinyl methyl ether, vinyl ethyl ether, and the like. Two or more are used. A carboxylic acid group containing copolymer may be used individually by 1 type, and may use 2 or more types together.
The concentration of the carboxylic acid group-containing copolymer to be added to the aqueous system is desirably 3 to 20 mg / L as solid content, particularly 5 to 15 mg / L as solid content.
本発明において、酸化性物質としては、次亜塩素酸及びその塩、次亜臭素酸及びその塩、塩素化イソシアヌル酸及びその塩、例えば塩素化スルファミン酸及びその塩や臭素化スルファミン酸及びその塩のようなクロラミン化合物、ブロマミン化合物、過酸化水素などが挙げられ、その１種又は２種以上を用いることができる。また、次亜塩素酸及びその塩や次亜臭素酸及びその塩と、５，５−ジメイルヒダントインやスルファミン酸などとを水系内で反応させて生成した酸化性物質を用いることもできる。
酸化性物質としては、クロラミン化合物が好ましく、塩素化スルアファミン酸及び／又はその塩を用いることがより好ましい。
In the present invention, the oxidizing substance includes hypochlorous acid and salts thereof, hypobromite and salts thereof, chlorinated isocyanuric acid and salts thereof, such as chlorinated sulfamic acid and salts thereof, and brominated sulfamic acid and salts thereof. Such as chloramine compound, bromamine compound, hydrogen peroxide and the like, and one or more of them can be used. Moreover, the oxidizing substance produced | generated by making hypochlorous acid and its salt, hypobromite, and its salt react with 5, 5- dimethylhydantoin, sulfamic acid, etc. can also be used.
As the oxidizing substance, a chloramine compound is preferable, and chlorinated sulfafamic acid and / or a salt thereof is more preferably used.
酸化性物質濃度は、ＤＰＤ法にて試薬添加１０秒後の発色が遊離塩素濃度０．５ｍｇ／Ｌ ａｓ Ｃｌ2以下かつ３０秒後の発色が遊離塩素濃度１ｍｇ／Ｌ ａｓ Ｃｌ2以下に相当するように管理する。このように酸化性物質濃度を管理する背景としては、酸化力の程度により遊離塩素濃度測定用に添加したＤＰＤ法の試薬が徐々に発色する場合があるためである。より強い酸化力を持つ酸化性物質は試薬添加後きわめて短時間に発色するため、試薬添加１０秒以下の短時間における発色の程度により管理を行うことができるが、測定作業を考慮し試薬添加１０秒後の発色に基づく測定値を用いることとした。ＤＰＤ法の試薬添加後、徐々に発色する酸化性物質に関しては、試薬添加３０秒から３分における発色の程度により管理を行うことができるが、発色が安定する試薬添加３０秒後の発色に基づく測定値を用いることとした。 The oxidizing substance concentration corresponds to a free chlorine concentration of 0.5 mg / L as Cl 2 or less after 10 seconds of reagent addition and a color development after 30 seconds of 1 mg / L as Cl 2 or less after 30 seconds after addition of the reagent by the DPD method. To manage. The background of managing the oxidizing substance concentration in this way is that the DPD reagent added for measuring the free chlorine concentration may gradually develop color depending on the degree of oxidizing power. An oxidizing substance having a stronger oxidizing power develops color in a very short time after the addition of the reagent, and therefore can be managed depending on the degree of color development in a short time of 10 seconds or less of the reagent addition. The measured value based on the color development after 2 seconds was used. Oxidizing substances that gradually develop color after addition of reagents in the DPD method can be managed according to the degree of color development in 30 seconds to 3 minutes after addition of the reagent. The measured value was used.
酸化性物質の添加濃度が上記上限よりも多いと、アゾール系銅用防食剤を併用しても銅系部材の腐食を抑制し得ない場合がある。ただし、酸化性物質の添加濃度が少な過ぎると酸化性物質によるスライム抑制効果を十分に得ることができないため、ＤＰＤ法にて試薬添加１０秒後の発色が遊離塩素濃度０．１ｍｇ／Ｌ ａｓ Ｃｌ2以上、例えば０．１〜０．５ｍｇ／Ｌ ａｓ Ｃｌ2で、かつ３０秒後の発色が遊離塩素濃度０．２ｍｇ／Ｌ ａｓ Ｃｌ2以上、例えば０．２〜１．０ｍｇ／Ｌ ａｓ Ｃｌ2となるように添加することが好ましい。 If the additive concentration of the oxidizing substance is higher than the above upper limit, the corrosion of the copper-based member may not be suppressed even when the azole-based copper anticorrosive is used in combination. However, if the addition concentration of the oxidizing substance is too small, the slime suppression effect due to the oxidizing substance cannot be obtained sufficiently, so that the color development 10 seconds after the addition of the reagent by the DPD method has a free chlorine concentration of 0.1 mg / L as Cl. 2 or more, for example 0.1-0.5 mg / L the as in Cl 2, and color development after 30 seconds of free chlorine concentration 0.2mg / L as Cl 2 or more, for example 0.2~1.0mg / L as Cl It is preferable to add so as to be 2 .
本発明において用いるアゾール系銅用防食剤としては、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などが挙げられ、その１種又は２種以上が用いられる。 Examples of the azole copper anticorrosive used in the present invention include benzotriazole, tolyltriazole, and mercaptobenzothiazole, and one or more of them are used.
アゾール系銅用防食剤は、下記（１）式で算出されるアゾール系銅用防食剤必要添加濃度（ｍｇ／Ｌ）以上に添加される。アゾール系銅用防食剤の添加量が以下のアゾール系銅用防食剤必要添加濃度（ｍｇ／Ｌ）未満であると、銅系部材の腐食抑制効果を十分に得ることができない。 The azole copper anticorrosive is added to the azole copper anticorrosive necessary addition concentration (mg / L) or more calculated by the following formula (1). When the addition amount of the azole copper anticorrosive is less than the following required concentration of azole copper anticorrosive (mg / L), the corrosion-inhibiting effect of the copper member cannot be sufficiently obtained.
アゾール系銅用防食剤必要濃度（ｍｇ／Ｌ）
＝Ｐ×０．２＋Ｓ×０．４＋Ｏ×１０ （１）
Ｐ：リン含有化合物濃度（ｍｇ／Ｌ ａｓ ＰＯ4 3-）
Ｓ：カルボン酸基含有共重合体濃度（ｍｇ／Ｌ ａｓ 固形分）
Ｏ：酸化性物質濃度※（ｍｇ／Ｌ ａｓ Ｃｌ2）
※ＤＰＤ法の試薬添加１０秒後の発色に相当する遊離塩素濃度
Required concentration of anticorrosive for azole copper (mg / L)
= P × 0.2 + S × 0.4 + O × 10 (1)
P: Phosphorus-containing compound concentration (mg / L as PO 4 3− )
S: Concentration of carboxylic acid group-containing copolymer (mg / L as solid content)
O: Oxidizing substance concentration * (mg / L as Cl 2 )
* Free chlorine concentration corresponding to color development 10 seconds after addition of reagent in DPD method
アゾール系銅用防食剤の添加濃度は、上記アゾール系銅用防食剤必要添加濃度（ｍｇ／Ｌ）以上であればよいが、アゾール系銅用防食剤の添加量が過度に多いと不経済であることから、アゾール系銅用防食剤は、上記アゾール系銅用防食剤必要添加濃度（ｍｇ／Ｌ）をＡｍｇ／Ｌとした場合において、Ａｍｇ／Ｌ〜（Ａ＋５）ｍｇ／Ｌ、特にＡｍｇ／Ｌ〜（Ａ＋２）ｍｇ／Ｌの範囲で添加することが好ましい。 The concentration of the azole copper anticorrosive added may be equal to or higher than the concentration required for the azole copper anticorrosive (mg / L), but it is uneconomical if the amount of the azole copper anticorrosive added is excessively large. Therefore, the azole copper anticorrosive has a concentration of Amg / L to (A + 5) mg / L, especially Amg / L, when the azole copper anticorrosive necessary concentration (mg / L) is Amg / L. It is preferable to add in the range of L to (A + 2) mg / L.
本発明で用いられるリン含有化合物、カルボン酸基含有共重合体、酸化性物質及びアゾール系銅用防食剤は、本発明で規定する酸化性物質及びアゾール系銅用防食剤の濃度範囲を満足する範囲において、それぞれ単独で水系へ添加することも可能であるし、一部又は全部を予め混合して一剤化した形態で水系へ添加することも可能である。 The phosphorus-containing compound, carboxylic acid group-containing copolymer, oxidizing substance, and azole copper anticorrosive used in the present invention satisfy the concentration ranges of the oxidizing substance and azole copper anticorrosive specified in the present invention. In the range, each can be added to the aqueous system alone, or a part or all of them can be mixed in advance and added to the aqueous system in the form of a single agent.
本発明において、リン含有化合物とカルボン酸基含有共重合体とは、任意に組み合わせて用いることが可能であるが、銅系部材の腐食抑制という目的以外の効果、例えば炭素鋼に対する腐食抑制効果なども考慮した場合、リン含有化合物として２−ホスホノブタン−１，２，４−トリカルボン酸、リン含有化合物としてマレイン酸とイソブチレンの共重合体、あるいはアクリル酸と２−アクリルアミド−２−メチルプロパンスルホン酸の共重合体を用いることが好ましい。また、アゾール系銅用防食剤は、酸化性物質と一剤配合することを考慮すると、有効成分の安定性の面からベンゾトリアゾールが好ましい。 In the present invention, the phosphorus-containing compound and the carboxylic acid group-containing copolymer can be used in any combination, but the effects other than the purpose of inhibiting the corrosion of the copper-based member, for example, the corrosion inhibiting effect on carbon steel, etc. In consideration of the above, 2-phosphonobutane-1,2,4-tricarboxylic acid as a phosphorus-containing compound, a copolymer of maleic acid and isobutylene as a phosphorus-containing compound, or acrylic acid and 2-acrylamido-2-methylpropanesulfonic acid. It is preferable to use a copolymer. Moreover, the azole type anticorrosive for copper is preferably benzotriazole from the viewpoint of the stability of the active ingredient, considering that one agent is combined with the oxidizing substance.
本発明の実施にあたっては、本発明の効果を阻害しない範囲で、リン含有化合物、カルボン酸基含有共重合体、酸化性物質及びアゾール系銅用防食剤以外の他の水処理剤、例えば防食剤、スケール防止剤、スライム処理剤、消泡剤、界面活性剤、キレート剤などを併用することが可能である。 In carrying out the present invention, water treatment agents other than phosphorus-containing compounds, carboxylic acid group-containing copolymers, oxidizing substances, and azole copper anticorrosives, such as anticorrosives, as long as the effects of the present invention are not impaired. Scale inhibitors, slime treatment agents, antifoaming agents, surfactants, chelating agents and the like can be used in combination.
なお、本発明において、処理対象水系のカルシウム硬度が１００ｍｇ／Ｌ ａｓ ＣａＣＯ3未満であることは極めて重要であり、カルシウム硬度が１００ｍｇ／Ｌ ａｓ ＣａＣＯ3以上の水系では、通常、リン含有化合物、カルボン酸基含有共重合体、酸化性物質及びアゾール系銅用防食剤の併用による銅系部材の腐食の問題は比較的発生しにくい。カルシウム硬度が１００ｍｇ／Ｌ ａｓ ＣａＣＯ3未満であり、リン含有化合物、カルボン酸基含有共重合体、酸化性物質及びアゾール系銅用防食剤を併用しても、銅系部材の腐食の問題のある水系に対して本発明は有効である。この水系のカルシウム硬度はより好ましくは５０ｍｇ／Ｌ ａｓ ＣａＣＯ3未満、特に好ましくは０〜２０ｍｇ／Ｌ ａｓ ＣａＣＯ3である。 In the present invention, the processing object that calcium hardness of the aqueous is less than 100mg / L as CaCO 3 is extremely important, the calcium hardness of 100mg / L as CaCO 3 or more aqueous, typically, phosphorus-containing compounds, carboxylic The problem of corrosion of the copper-based member due to the combined use of the acid group-containing copolymer, the oxidizing substance, and the azole-based copper anticorrosive is relatively unlikely to occur. Calcium hardness is less than 100 mg / L as CaCO 3 , and there is a problem of corrosion of copper-based members even when a phosphorus-containing compound, a carboxylic acid group-containing copolymer, an oxidizing substance, and an azole copper anticorrosive are used in combination. The present invention is effective for aqueous systems. Calcium hardness of the water system more preferably less than 50mg / L as CaCO 3, particularly preferably 0~20mg / L as CaCO 3.
以下に実施例及び比較例を挙げて本発明をより具体的に説明する。
以下の実施例及び比較例で用いた薬剤は、以下の略号で示す。
Hereinafter, the present invention will be described more specifically with reference to Examples and Comparative Examples.
The chemicals used in the following examples and comparative examples are indicated by the following abbreviations.
［実施例１〜１０，比較例１〜１２］
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い、試験前後の銅試験片の重量変化より銅の腐食速度を測定する方法で腐食抑制効果の評価を行った。
試験水、試験片、試験条件は以下の通りである。
・試験水 ：純水に塩化ナトリウム及び硫酸ナトリウムを添加し、塩化物イオン濃度５０ｍｇ／Ｌ ａｓ Ｃｌ-、硫酸イオン濃度５０ｍｇ／Ｌ ａｓ ＳＯ4 2-となるように調整した試験水に、表２，３に示す成分を表２，３に示す濃度で添加したものを用いた。ｐＨは試験水の酸消費量（ｐＨ４．８）に相当する平衡ｐＨとなるよう炭酸ガスあるいは空気を曝気して調整した。一部条件では硝酸カルシウムを添加しカルシウム硬度を任意の濃度に調整した。
・試験片 ：長辺５０ｍｍ、短辺３０ｍｍ、厚さ１ｍｍの銅（Ｃ１２２０）製試験片（ねじ止め用のφ４ｍｍ穴あき）を用いた。
・試験温度：４０℃
・試験期間：３日間
・流動条件：試験片回転速度１６０ｒｐｍ（流速０．５ｍ／ｓｅｃ相当）
[Examples 1 to 10, Comparative Examples 1 to 12]
Evaluation based on "Rotating method" described in JIS K0100 "Industrial water corrosion test method" is performed, and the corrosion inhibition effect is evaluated by measuring the corrosion rate of copper from the change in weight of the copper specimen before and after the test. It was.
Test water, test pieces, and test conditions are as follows.
Test water: Sodium chloride and sodium sulfate were added to pure water, and the test water was adjusted to have a chloride ion concentration of 50 mg / L as Cl − and a sulfate ion concentration of 50 mg / L as SO 4 2-. , 3 were added at the concentrations shown in Tables 2 and 3. The pH was adjusted by aeration of carbon dioxide gas or air so as to obtain an equilibrium pH corresponding to the acid consumption (pH 4.8) of the test water. Under some conditions, calcium nitrate was added to adjust the calcium hardness to an arbitrary concentration.
Test piece: 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 (φ4 mm hole for screwing) was used.
Test temperature: 40 ° C
・ Test period: 3 days ・ Flow conditions: Test piece rotation speed 160 rpm (equivalent to a flow rate of 0.5 m / sec)
試験結果を表２，３に示す。 The test results are shown in Tables 2 and 3.
実施例１〜１０の結果は、カルシウム硬度が１００ｍｇ／Ｌ ａｓ ＣａＣＯ3未満で、リン含有化合物と、カルボン酸基含有共重合体と、酸化性物質を併用する水処理において、ＤＰＤ法にて試薬添加１０秒後の発色が遊離塩素濃度０．５ｍｇ／Ｌ ａｓ Ｃｌ2以下かつ３０秒後の発色が遊離塩素濃度１ｍｇ／Ｌ ａｓ Ｃｌ2以下に相当するように酸化性物質濃度を管理するとともに、アゾール系銅用防食剤を前記（１）式で算出するアゾール系銅用防食剤必要濃度（ｍｇ／Ｌ）以上に添加することにより、銅の腐食速度を２．５ｍｄｄ未満の十分低い値に抑制可能なことを示している。
比較例１は、リン含有化合物と、カルボン酸基含有共重合体と、アゾール系銅用防食剤を併用する水処理において、酸化性物質を併用しない場合にアゾール系銅用防食剤濃度が低い場合でも、銅の腐食速度が十分低い値に抑制されることを示している。
一方、比較例２〜５及び比較例７〜１２より、酸化性物質を併用することにより銅の腐食速度が著しく促進されることが明らかである。
比較例４〜６より、カルシウム硬度が１００ｍｇ／Ｌ ａｓ ＣａＣＯ3未満で、リン含有化合物及びカルボン酸基含有共重合体と酸化性物質併用により銅の腐食が促進されることが明らかである。
比較例７及び１２は、カルシウム硬度が１００ｍｇ／Ｌ ａｓ ＣａＣＯ3未満で、リン含有化合物と、カルボン酸基含有共重合体と、酸化性物質を併用する水処理において、ＤＰＤ法にて試薬添加１０秒後の発色が遊離塩素濃度０．５ｍｇ／Ｌ ａｓ Ｃｌ2超える、あるいは３０秒後の発色が遊離塩素濃度１ｍｇ／Ｌ ａｓ Ｃｌ2を超えるように酸化性物質濃度を管理した結果、アゾール系銅用防食剤濃度が本発明の範囲内であっても、銅の腐食を十分抑制できないことを示している。
The results of Examples 1 to 10 show that the calcium hardness is less than 100 mg / L as CaCO 3 , and the reagent in the DPD method is used in water treatment using a phosphorus-containing compound, a carboxylic acid group-containing copolymer, and an oxidizing substance in combination. In addition to controlling the oxidizing substance concentration so that the color development after 10 seconds of addition corresponds to a free chlorine concentration of 0.5 mg / L as Cl 2 or less and the color development after 30 seconds corresponds to a free chlorine concentration of 1 mg / L as Cl 2 or less, By adding the azole copper anticorrosive to the azole copper anticorrosive necessary concentration (mg / L) or more calculated by the formula (1), the copper corrosion rate is suppressed to a sufficiently low value of less than 2.5 mdd. It shows what is possible.
Comparative Example 1 shows a case where the concentration of the azole copper anticorrosive is low when the oxidizing substance is not used in combination in the water treatment using the phosphorus-containing compound, the carboxylic acid group-containing copolymer, and the azole copper anticorrosive. However, it shows that the corrosion rate of copper is suppressed to a sufficiently low value.
On the other hand, it is clear from Comparative Examples 2 to 5 and Comparative Examples 7 to 12 that the corrosion rate of copper is significantly accelerated by using an oxidizing substance in combination.
From Comparative Examples 4 to 6, it is clear that the calcium hardness is less than 100 mg / L as CaCO 3 and the corrosion of copper is promoted by the combined use of the phosphorus-containing compound, the carboxylic acid group-containing copolymer and the oxidizing substance.
In Comparative Examples 7 and 12, in the water treatment in which the calcium hardness is less than 100 mg / L as CaCO 3 and the phosphorus-containing compound, the carboxylic acid group-containing copolymer, and the oxidizing substance are used in combination, the reagent is added by the DPD method. As a result of controlling the oxidizing substance concentration so that the color development after 2 seconds exceeded the free chlorine concentration of 0.5 mg / L as Cl 2 , or the color development after 30 seconds exceeded the free chlorine concentration of 1 mg / L as Cl 2 , the azole copper Even if the concentration of the anticorrosive agent is within the range of the present invention, the corrosion of copper cannot be sufficiently suppressed.
Claims (5)
ＤＰＤ法にて試薬添加１０秒後の発色が遊離塩素濃度０．５ｍｇ／Ｌ ａｓ Ｃｌ2以下かつ３０秒後の発色が遊離塩素濃度１ｍｇ／Ｌ ａｓ Ｃｌ2以下に相当するように、該水系の酸化性物質濃度を管理するとともに、該水系に、アゾール系銅用防食剤を、下記（１）式で算出されるアゾール系銅用防食剤必要濃度（ｍｇ／Ｌ）をＡｍｇ／Ｌとした場合において、Ａｍｇ／Ｌ〜（Ａ＋５）ｍｇ／Ｌの範囲で添加することを特徴とする銅系部材の腐食抑制方法。
アゾール系銅用防食剤必要濃度（ｍｇ／Ｌ）
＝Ｐ×０．２＋Ｓ×０．４＋Ｏ×１０ （１）
Ｐ：リン含有化合物濃度（ｍｇ／Ｌ ａｓ ＰＯ4 3-）
Ｓ：カルボン酸基含有共重合体濃度（ｍｇ／Ｌ ａｓ 固形分）
Ｏ：酸化性物質濃度※（ｍｇ／Ｌ ａｓ Ｃｌ2）
※ＤＰＤ法の試薬添加１０秒後の発色に相当する遊離塩素濃度 In an aqueous system having a calcium hardness of less than 100 mg / L as CaCO 3 , a method of suppressing corrosion of a copper-based member in contact with the aqueous system by adding a phosphorus-containing compound, a carboxylic acid group-containing copolymer, and an oxidizing substance. There,
In the DPD method, the aqueous system was developed so that the color development after 10 seconds of reagent addition corresponds to a free chlorine concentration of 0.5 mg / L as Cl 2 or less and the color development after 30 seconds corresponds to a free chlorine concentration of 1 mg / L as Cl 2 or less. In the case where the concentration of the oxidizer is controlled with the azole copper anticorrosive agent and the required concentration (mg / L) of the azole copper anticorrosive agent calculated by the following formula (1) is Amg / L. In addition, it adds in the range of Amg / L-(A + 5) mg / L, The corrosion suppression method of the copper-type member characterized by the above-mentioned.
Required concentration of anticorrosive for azole copper (mg / L)
= P × 0.2 + S × 0.4 + O × 10 (1)
P: Phosphorus-containing compound concentration (mg / L as PO 4 3− )
S: Concentration of carboxylic acid group-containing copolymer (mg / L as solid content)
O: Oxidizing substance concentration * (mg / L as Cl 2 )
* Free chlorine concentration corresponding to color development 10 seconds after addition of reagent in DPD method
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