JPWO2005123981A1 - Metal pitting inhibitor and method - Google Patents
Metal pitting inhibitor and method Download PDFInfo
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- JPWO2005123981A1 JPWO2005123981A1 JP2006514850A JP2006514850A JPWO2005123981A1 JP WO2005123981 A1 JPWO2005123981 A1 JP WO2005123981A1 JP 2006514850 A JP2006514850 A JP 2006514850A JP 2006514850 A JP2006514850 A JP 2006514850A JP WO2005123981 A1 JPWO2005123981 A1 JP WO2005123981A1
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- 229910052751 metal Inorganic materials 0.000 title claims abstract description 42
- 239000002184 metal Substances 0.000 title claims abstract description 42
- 239000003112 inhibitor Substances 0.000 title claims abstract description 28
- 238000000034 method Methods 0.000 title claims abstract description 20
- 229920001577 copolymer Polymers 0.000 claims abstract description 89
- 230000007797 corrosion Effects 0.000 claims abstract description 75
- 238000005260 corrosion Methods 0.000 claims abstract description 75
- 150000001875 compounds Chemical class 0.000 claims abstract description 32
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- VZCYOOQTPOCHFL-UPHRSURJSA-N maleic acid Chemical compound OC(=O)\C=C/C(O)=O VZCYOOQTPOCHFL-UPHRSURJSA-N 0.000 claims abstract description 27
- 239000011976 maleic acid Substances 0.000 claims abstract description 27
- 125000001165 hydrophobic group Chemical group 0.000 claims abstract description 25
- 125000004432 carbon atom Chemical group C* 0.000 claims abstract description 22
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- 150000001993 dienes Chemical class 0.000 claims abstract description 13
- 125000003178 carboxy group Chemical group [H]OC(*)=O 0.000 claims abstract description 12
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- 125000000542 sulfonic acid group Chemical group 0.000 claims description 30
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- 125000004435 hydrogen atom Chemical group [H]* 0.000 claims description 16
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- 150000001340 alkali metals Chemical class 0.000 claims description 5
- 229910052739 hydrogen Inorganic materials 0.000 claims description 5
- 239000001257 hydrogen Substances 0.000 claims description 5
- 125000003118 aryl group Chemical group 0.000 claims description 4
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- 239000003814 drug Substances 0.000 description 3
- 229940079593 drug Drugs 0.000 description 3
- 229910001385 heavy metal Inorganic materials 0.000 description 3
- RAXXELZNTBOGNW-UHFFFAOYSA-N imidazole Natural products C1=CNC=N1 RAXXELZNTBOGNW-UHFFFAOYSA-N 0.000 description 3
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- XHZPRMZZQOIPDS-UHFFFAOYSA-N 2-Methyl-2-[(1-oxo-2-propenyl)amino]-1-propanesulfonic acid Chemical compound OS(=O)(=O)CC(C)(C)NC(=O)C=C XHZPRMZZQOIPDS-UHFFFAOYSA-N 0.000 description 2
- UIERETOOQGIECD-UHFFFAOYSA-N Angelic acid Natural products CC=C(C)C(O)=O UIERETOOQGIECD-UHFFFAOYSA-N 0.000 description 2
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- VZCYOOQTPOCHFL-OWOJBTEDSA-N Fumaric acid Chemical compound OC(=O)\C=C\C(O)=O VZCYOOQTPOCHFL-OWOJBTEDSA-N 0.000 description 2
- CERQOIWHTDAKMF-UHFFFAOYSA-N Methacrylic acid Chemical compound CC(=C)C(O)=O CERQOIWHTDAKMF-UHFFFAOYSA-N 0.000 description 2
- 229910019142 PO4 Inorganic materials 0.000 description 2
- OAICVXFJPJFONN-UHFFFAOYSA-N Phosphorus Chemical compound [P] OAICVXFJPJFONN-UHFFFAOYSA-N 0.000 description 2
- CSXQFIFKZOKDAY-UHFFFAOYSA-N [NH4+].CC(C=C)=CS([O-])(=O)=O Chemical compound [NH4+].CC(C=C)=CS([O-])(=O)=O CSXQFIFKZOKDAY-UHFFFAOYSA-N 0.000 description 2
- 238000005273 aeration Methods 0.000 description 2
- 239000007864 aqueous solution Substances 0.000 description 2
- IOJUPLGTWVMSFF-UHFFFAOYSA-N benzothiazole Chemical compound C1=CC=C2SC=NC2=C1 IOJUPLGTWVMSFF-UHFFFAOYSA-N 0.000 description 2
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- 238000004519 manufacturing process Methods 0.000 description 2
- 229910021645 metal ion Inorganic materials 0.000 description 2
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- NBIIXXVUZAFLBC-UHFFFAOYSA-K phosphate Chemical compound [O-]P([O-])([O-])=O NBIIXXVUZAFLBC-UHFFFAOYSA-K 0.000 description 2
- 239000010452 phosphate Substances 0.000 description 2
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- 239000007870 radical polymerization initiator Substances 0.000 description 2
- RWDRUPBYYPJXOA-UHFFFAOYSA-M sodium;2-methylbuta-1,3-diene-1-sulfonate Chemical compound [Na+].C=CC(C)=CS([O-])(=O)=O RWDRUPBYYPJXOA-UHFFFAOYSA-M 0.000 description 2
- 239000000126 substance Substances 0.000 description 2
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- BCMCBBGGLRIHSE-UHFFFAOYSA-N 1,3-benzoxazole Chemical compound C1=CC=C2OC=NC2=C1 BCMCBBGGLRIHSE-UHFFFAOYSA-N 0.000 description 1
- QWENRTYMTSOGBR-UHFFFAOYSA-N 1H-1,2,3-Triazole Chemical compound C=1C=NNN=1 QWENRTYMTSOGBR-UHFFFAOYSA-N 0.000 description 1
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- UIERETOOQGIECD-ARJAWSKDSA-M 2-Methyl-2-butenoic acid Natural products C\C=C(\C)C([O-])=O UIERETOOQGIECD-ARJAWSKDSA-M 0.000 description 1
- 125000000954 2-hydroxyethyl group Chemical group [H]C([*])([H])C([H])([H])O[H] 0.000 description 1
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- 229910052708 sodium Inorganic materials 0.000 description 1
- 239000011780 sodium chloride Substances 0.000 description 1
- FAPWRFPIFSIZLT-UHFFFAOYSA-M sodium chloride Inorganic materials [Na+].[Cl-] FAPWRFPIFSIZLT-UHFFFAOYSA-M 0.000 description 1
- 159000000000 sodium salts Chemical class 0.000 description 1
- 239000002904 solvent Substances 0.000 description 1
- 239000010421 standard material Substances 0.000 description 1
- BDHFUVZGWQCTTF-UHFFFAOYSA-M sulfonate Chemical compound [O-]S(=O)=O BDHFUVZGWQCTTF-UHFFFAOYSA-M 0.000 description 1
- 150000003536 tetrazoles Chemical class 0.000 description 1
- VLLMWSRANPNYQX-UHFFFAOYSA-N thiadiazole Chemical compound C1=CSN=N1.C1=CSN=N1 VLLMWSRANPNYQX-UHFFFAOYSA-N 0.000 description 1
- UIERETOOQGIECD-ONEGZZNKSA-N tiglic acid Chemical compound C\C=C(/C)C(O)=O UIERETOOQGIECD-ONEGZZNKSA-N 0.000 description 1
- UAXOELSVPTZZQG-UHFFFAOYSA-N tiglic acid Natural products CC(C)=C(C)C(O)=O UAXOELSVPTZZQG-UHFFFAOYSA-N 0.000 description 1
- GTZCVFVGUGFEME-UHFFFAOYSA-N trans-aconitic acid Natural products OC(=O)CC(C(O)=O)=CC(O)=O GTZCVFVGUGFEME-UHFFFAOYSA-N 0.000 description 1
- 239000011701 zinc Substances 0.000 description 1
- 229910052725 zinc Inorganic materials 0.000 description 1
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- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23F—NON-MECHANICAL REMOVAL OF METALLIC MATERIAL FROM SURFACE; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL; MULTI-STEP PROCESSES FOR SURFACE TREATMENT OF METALLIC MATERIAL INVOLVING AT LEAST ONE PROCESS PROVIDED FOR IN CLASS C23 AND AT LEAST ONE PROCESS COVERED BY SUBCLASS C21D OR C22F OR CLASS C25
- C23F11/00—Inhibiting corrosion of metallic material by applying inhibitors to the surface in danger of corrosion or adding them to the corrosive agent
- C23F11/08—Inhibiting corrosion of metallic material by applying inhibitors to the surface in danger of corrosion or adding them to the corrosive agent in other liquids
- C23F11/10—Inhibiting corrosion of metallic material by applying inhibitors to the surface in danger of corrosion or adding them to the corrosive agent in other liquids using organic inhibitors
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- Materials Engineering (AREA)
- Mechanical Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Preventing Corrosion Or Incrustation Of Metals (AREA)
- Compositions Of Macromolecular Compounds (AREA)
Abstract
（Ａ）一般式［１］で表される共役ジエンのスルホン化物１モルに対して、一般式［２］で表されるカルボキシル基を有する不飽和化合物０．１〜２０モルを共重合したスルホン酸基を有する共重合体、（Ｂ）マレイン酸１モルに対して、炭素数４〜１０のアルケン０．８〜１．３モルを共重合した疎水基を有する共重合体及び（Ｃ）アゾール化合物を含有する金属の孔食抑制剤、及び、該孔食抑制剤を、（Ａ）、（Ｂ）及び（Ｃ）各成分の合計として、水系に１〜１００ｍｇ／Ｌ添加する金属の孔食抑制方法。ただし、Ｒ１〜Ｒ６の少なくとも一つは−ＳＯ３Ｘであり、Ｒ７〜Ｒ１０の少なくとも一つは−（ＣＨ２）ｍＣＯＯＭである。前記孔食抑制剤の使用により、開放循環冷却水系において、水と接する部分に炭素鋼を有する設備の寿命を効果的に延長することができる。(A) A sulfone obtained by copolymerizing 0.1 to 20 mol of an unsaturated compound having a carboxyl group represented by the general formula [2] with 1 mol of a sulfonated compound of a conjugated diene represented by the general formula [1]. Copolymer having an acid group, (B) a copolymer having a hydrophobic group obtained by copolymerizing 0.8 to 1.3 mol of an alkene having 4 to 10 carbon atoms with 1 mol of maleic acid, and (C) an azole. Metal pitting inhibitor containing a compound, and the pitting corrosion inhibitor of the metal which is added to the aqueous system in an amount of 1 to 100 mg/L as the sum of the components (A), (B) and (C). Suppression method. However, at least one of R 1 to R 6 is —SO 3 X, and at least one of R 7 to R 10 is —(CH 2 ) m COOM. By using the pitting corrosion inhibitor, it is possible to effectively extend the service life of equipment having carbon steel in a portion in contact with water in an open circulation cooling water system.
Description
本発明は、金属の孔食抑制剤及び孔食抑制方法に関する。さらに詳しくは、本発明は、開放循環冷却水系において、リン化合物や亜鉛塩などの重金属塩を用いることなく、炭素鋼の孔食の進行を抑制し、熱交換器などの設備の寿命を効果的に延長することができる金属の孔食抑制剤及び孔食抑制方法に関する。 The present invention relates to a metal pitting corrosion inhibitor and a pitting corrosion inhibition method. More specifically, the present invention, in an open circulation cooling water system, suppresses the progress of pitting corrosion of carbon steel without using heavy metal salts such as phosphorus compounds and zinc salts, and effectively increases the life of equipment such as heat exchangers. The present invention relates to a metal pitting corrosion inhibitor and a pitting corrosion inhibiting method.
金属の腐食は、ファウリングとともに、冷却水系において発生する重大な障害の一つである。腐食は、冷却水系の設備の寿命の短縮、熱交換器チューブの貫通による製品の漏洩、汚染などの直接的な障害を引き起こすのみならず、腐食生成物の付着による熱交換器の熱効率の低下、ポンプ圧の上昇などの間接的な障害を発生させる。また、高温、高圧プロセスにおける事故の発生は、人身事故にもつながりかねない。冷却水中に溶存する難溶性塩が濃縮されて伝熱面にスケールとして析出したり、系内で微生物が増殖してスライムが付着すると、付着物の下部で局部腐食が進行することが多い。腐食環境にさらされた金属表面が全面で腐食する場合は、腐食による装置の寿命予測もしやすく、対策もたてやすいが、実際の系では局部腐食が多く、中でも、腐食した部分の間口の大きさに対する深さの比が大きい孔食が発生する場合が多い。このために、水系におけるスケールや腐食の発生を防止するために、さまざまな手段が講じられている。
例えば、ボイラー、熱交換器、凝縮器、配管などの水系において、スケール生成を防止するために用いる水処理剤として、共役ジエンのスルホン化物又はその重合体若しくは共重合体を含有する水処理剤が提案されている（特許文献１）。また、リンを含有せず、多価金属イオンと不溶性塩を生ずることがなく、スケール及び汚れ防止効果に優れ、その効果が長期間持続するとともに、金属腐食抑制効果にも優れた水処理剤として、共役ジエンスルホン酸若しくはその塩、（メタ）アクリル酸若しくはその塩、及び、（メタ）アクリル酸２−ヒドロキシエチル又は（メタ）アクリルアミド−２−メチルアルカンスルホン酸若しくはその塩より合成される３成分系共重合体を含有する水処理剤が提案されている（特許文献２）。
さらに、リン系薬剤及び亜鉛系薬剤を全く使用することなく、冷却水系における金属材料の腐食を効果的に防止することができる防食方法として、冷却水のＭアルカリ度をＡｍｇＣａＣＯ３／Ｌ、カルシウム硬度をＢｍｇＣａＣＯ３／Ｌ、シリカ濃度をＣｍｇＳｉＯ２／Ｌ、マグネシウム硬度をＤｍｇＣａＣＯ３／Ｌ、ランジェリア指数をＥ、水素イオン指数をｐＨ、水温をｔ℃としたとき、（１）２．４ｌｏｇＡ＋ｌｏｇＢ≧６．４及びＣ≧５０、（２）ｌｏｇＣ＋ｌｏｇＤ＋２ｐＨ＋８．５１ｌｏｇｔ≧３３、又は、（３）ｌｏｇＢ＋ｌｏｇＣ≧３．４及びＥ≧１．５を満たす水質に調整し、水溶性アニオンポリマーを添加する防食方法が提案されている（特許文献３）。また、環境汚染問題を惹き起こすことなく、水系と接する金属の腐食を効果的に防止ないし抑制する方法として、開放循環冷却水系において、水中のＳｉＯ２濃度を［ＳｉＯ２］（ｍｇＳｉＯ２／Ｌ）、カルシウム硬度を［ＣａＨ］（ｍｇＣａＣＯ３／Ｌ）としたとき、ランジェリア指数が１．５以上で、かつ、［ＳｉＯ２］×［ＣａＨ］≧２，０００となるように水質を調整し、次いで、重量平均分子量１，０００〜２０，０００のマレイン酸、無水マレイン酸又はこれらの水溶性塩とイソブチレンとの共重合体を添加する方法が提案されている（特許文献４）。
これらの手段によれば、スケール防止ないし金属腐食抑制効果は得られるが、孔食抑制に対する特効的な効果は得られない。マレイン酸−イソブチレン共重合体とカルシウム硬度、シリカ濃度を利用する防食方法は、水質上の制限が多く、孔食の抑制も不十分である場合がある。炭酸カルシウムの飽和指数と腐食傾向／スケール傾向の関係については、Ｊ．Ｗ．Ｒｙｚｎｅｒが報告している（非特許文献１）。リズナー指数６以上の水質では腐食傾向、リズナー指数６未満の水質ではスケール傾向となる。しかし、一般的にスケール傾向の水質では平均の腐食速度は低くなるが、孔食のような局部腐食が起きる場合があり、機器の寿命延長には不十分である。
［特許文献１］特許第２６２５９１４号公報（第１頁）
［特許文献２］特開平９−２４８５５５号公報（第２−３頁）
［特許文献３］特開２００４−１０７７８２号公報（第２−３頁）
［特許文献４］特公平４−３３８６８号公報（第１−２頁）
［非特許文献１］Ｊ．ＡＷＷＡ ３６ ４７２（１９４４）
本発明は、開放循環冷却水系において、リン化合物や亜鉛塩などの重金属塩を用いることなく、炭素鋼の孔食の進行を抑制し、熱交換器などの水と接する設備の寿命を効果的に延長することができる金属の孔食抑制剤及び孔食抑制方法を提供することを目的としてなされたものである。Metal fouling, along with fouling, is one of the major obstacles that occur in cooling water systems. Corrosion not only causes a short life of the cooling water system facility, product leakage due to penetration of the heat exchanger tube, direct damage such as contamination, but also deterioration of the heat efficiency of the heat exchanger due to the adhesion of corrosion products, It causes indirect obstacles such as increase of pump pressure. In addition, the occurrence of accidents in high temperature and high pressure processes can lead to personal injury. When the sparingly soluble salt dissolved in the cooling water is concentrated and deposited as a scale on the heat transfer surface, or when the microorganisms grow in the system and slime adheres, local corrosion often progresses at the bottom of the adhered material. If the entire metal surface exposed to a corrosive environment corrodes, it is easy to predict the life of the equipment due to corrosion and it is easy to take countermeasures, but in the actual system there is a lot of local corrosion, and the frontage of the corroded part is large. Pitting corrosion often occurs with a large depth to depth ratio. For this reason, various measures have been taken to prevent the occurrence of scale and corrosion in water systems.
For example, in a water system such as a boiler, a heat exchanger, a condenser, and a pipe, as a water treatment agent used for preventing scale formation, a water treatment agent containing a sulfonated product of a conjugated diene or a polymer or copolymer thereof. It has been proposed (Patent Document 1). In addition, as a water treatment agent that does not contain phosphorus, does not form polyvalent metal ions and insoluble salts, is excellent in the effect of preventing scale and stains, and the effect lasts for a long time, and is also excellent in the effect of inhibiting metal corrosion. , A conjugated dienesulfonic acid or a salt thereof, a (meth)acrylic acid or a salt thereof, and a 2-component compound synthesized from 2-hydroxyethyl (meth)acrylate or (meth)acrylamido-2-methylalkanesulfonic acid or a salt thereof A water treatment agent containing a system copolymer has been proposed (Patent Document 2).
Further, as an anticorrosion method capable of effectively preventing corrosion of a metal material in a cooling water system without using any phosphorus-based chemicals and zinc-based chemicals, M alkalinity of cooling water is AmgCaCO 3 /L, calcium hardness Is BmgCaCO 3 /L, silica concentration is CmgSiO 2 /L, magnesium hardness is DmgCaCO 3 /L, Langerian index is E, hydrogen ion index is pH, and water temperature is t° C., (1) 2.4logA+logB≧6 .4 and C≧50, (2)logC+logD+2pH+8.51logt≧33, or (3)logB+logC≧3.4 and E≧1.5, and a water-soluble anionic polymer is added to the anticorrosion method. (Patent Document 3). Further, as a method of effectively preventing or suppressing the corrosion of the metal in contact with the water system without causing the environmental pollution problem, the SiO 2 concentration in the water is [SiO 2 ] (mgSiO 2 /L) in the open circulation cooling water system. When the calcium hardness is [CaH] (mgCaCO 3 /L), the Langerian index is 1.5 or more, and the water quality is adjusted so that [SiO 2 ]×[CaH]≧2,000. Then, a method of adding a copolymer of maleic acid having a weight average molecular weight of 1,000 to 20,000, maleic anhydride or a water-soluble salt thereof and isobutylene has been proposed (Patent Document 4).
By these means, the effect of preventing scale or suppressing metal corrosion can be obtained, but the effect of suppressing pitting corrosion cannot be obtained. The anticorrosion method utilizing the maleic acid-isobutylene copolymer, calcium hardness, and silica concentration has many restrictions on water quality and may not sufficiently suppress pitting corrosion. For the relationship between the saturation index of calcium carbonate and the corrosion tendency/scale tendency, see J. W. Ryzner reports (Non-Patent Document 1). Water quality with a Rezner index of 6 or higher tends to corrode, and water quality with a Resner index of less than 6 tends to scale. However, in general, water quality that tends to scale has a low average corrosion rate, but local corrosion such as pitting corrosion may occur, which is insufficient for extending the life of the equipment.
[Patent Document 1] Japanese Patent No. 2625914 (page 1)
[Patent Document 2] JP-A-9-248555 (page 2-3)
[Patent Document 3] Japanese Patent Laid-Open No. 2004-107782 (page 2-3)
[Patent Document 4] Japanese Patent Publication No. 4-33868 (page 1-2)
[Non-Patent Document 1] J. AWWA 36 472 (1944)
The present invention, in the open circulation cooling water system, without using heavy metal salts such as phosphorus compounds and zinc salts, to suppress the progress of pitting corrosion of carbon steel, effectively the life of equipment such as heat exchangers in contact with water The object of the present invention is to provide a metal pitting corrosion inhibitor that can be extended and a pitting corrosion inhibition method.
本発明者らは、上記の課題を解決すべく鋭意研究を重ねた結果、（Ａ）共役ジエンのスルホン化物とカルボキシル基を有する不飽和化合物との共重合体、（Ｂ）マレイン酸とアルケンとの共重合体及び（Ｃ）アゾール化合物を含有する薬剤を水系に添加することにより、孔食の進行を効果的に抑制し得ることを見いだし、この知見に基づいて本発明を完成するに至った。
すなわち、本発明は、
（１）（Ａ）一般式［１］で表される共役ジエンのスルホン化物１モルに対して、一般式［２］で表されるカルボキシル基を有する不飽和化合物０．１〜２０モルを共重合したスルホン酸基を有する共重合体、（Ｂ）マレイン酸１モルに対して、炭素数４〜１０のアルケン０．８〜１．３モルを共重合した疎水基を有する共重合体及び（Ｃ）アゾール化合物を含有することを特徴とする金属の孔食抑制剤、
（２）（Ａ）スルホン酸基を有する共重合体１重量部に対して、（Ｂ）疎水基を有する共重合体０．０５〜８重量部及び（Ｃ）アゾール化合物０．００５〜０．１重量部含有する（１）記載の金属の孔食抑制剤、及び、
（３）（１）又は（２）記載の金属の孔食抑制剤を、（Ａ）スルホン酸基を有する共重合体、（Ｂ）疎水基を有する共重合体及び（Ｃ）アゾール化合物の合計として、水系に１〜１００ｍｇ／Ｌ添加することを特徴とする金属の孔食抑制方法、
を提供するものである。
さらに、本発明の好ましい態様として、
（４）アゾール化合物が、トリアゾールである（１）又は（２）記載の金属の孔食抑制剤、及び、
（５）トリアゾールが、ベンゾトリアゾール又はトリルトリアゾールである（４）記載の金属の孔食抑制剤、
を挙げることができる。As a result of earnest studies to solve the above problems, the present inventors have found that (A) a copolymer of a sulfonated compound of a conjugated diene and an unsaturated compound having a carboxyl group, (B) maleic acid and an alkene. It was found that the progress of pitting corrosion can be effectively suppressed by adding a drug containing the copolymer of (1) and the (C) azole compound to an aqueous system, and the present invention has been completed based on this finding. ..
That is, the present invention is
(1) (A) 0.1-20 mol of an unsaturated compound having a carboxyl group represented by the general formula [2] is used per 1 mol of a sulfonated compound of a conjugated diene represented by the general formula [1]. A copolymer having a polymerized sulfonic acid group, (B) a copolymer having a hydrophobic group obtained by copolymerizing 0.8 to 1.3 mol of an alkene having 4 to 10 carbon atoms with 1 mol of maleic acid, and ( C) Metal pitting corrosion inhibitor characterized by containing an azole compound,
(2) 0.05 to 8 parts by weight of the copolymer (B) having a hydrophobic group and 0.005 to 0.50% of an azole compound (C) to 1 part by weight of the copolymer (A) having a sulfonic acid group. 1 parts by weight of the metal pitting inhibitor according to (1), and
(3) The total of the metal pitting inhibitor described in (1) or (2), (A) a copolymer having a sulfonic acid group, (B) a copolymer having a hydrophobic group, and (C) an azole compound. As a method for inhibiting pitting corrosion of metal, the method comprises adding 1 to 100 mg/L to an aqueous system,
Is provided.
Furthermore, as a preferred embodiment of the present invention,
(4) The pitting corrosion inhibitor for metal according to (1) or (2), wherein the azole compound is triazole, and
(5) The metal pitting inhibitor according to (4), wherein the triazole is benzotriazole or tolyltriazole.
Can be mentioned.
Ｆｉｇ．１は実施例で用いた通水試験装置の系統図である。図中、符号１はタンク、２はポンプ、３は炭素鋼管、４は炭素鋼管、５は銅管、６は腐食計を表す。 Fig. 1 is a system diagram of the water flow test apparatus used in the examples. In the figure, reference numeral 1 is a tank, 2 is a pump, 3 is a carbon steel tube, 4 is a carbon steel tube, 5 is a copper tube, and 6 is a corrosion meter.
本発明の金属の孔食抑制剤は、（Ａ）一般式［１］で表される共役ジエンのスルホン化物１モルに対して、一般式［２］で表されるカルボキシル基を有する不飽和化合物０．１〜２０モルを共重合したスルホン酸基を有する共重合体、（Ｂ）マレイン酸１モルに対して、炭素数４〜１０のアルケン０．８〜１．３モルを共重合した疎水基を有する共重合体及び（Ｃ）アゾール化合物を含有する。
一般式［１］で表される共役ジエンのスルホン化物としては、共役ジエンのスルホン酸、及びそのアルカリ金属塩、アルカリ土類金属塩、アンモニウム塩又はアミン塩などが挙げられ、その具体的化合物としては例えば、２−メチル−１，３−ブタジエン−１−スルホン酸、２−メチル−１，３−ブタジエン−３−スルホン酸、２−メチル−１，３−ブタジエン−４−スルホン酸、１，３−ペンタジエン−１−スルホン酸、１，３−ペンタジエン−２−スルホン酸、１，３−ペンタジエン−３−スルホン酸、１，３−ペンタジエン−４−スルホン酸、２，３−ジメチルブタジエン−１−スルホン酸、２−メチル−１，３−ペンタジエン−４−スルホン酸、３−メチル−１，３−ペンタジエン−１−スルホン酸、２−メチル−１，３−ブタジエン−１，３−ジスルホン酸、２−メチル−１，３−ブタジエン−１，４−ジスルホン酸、２−メチル−１，３−ブタジエン−１−スルホン酸ナトリウム（イソプレンスルホン酸ナトリウム）、２−メチル−１，３−ブタジエン−１−スルホン酸カリウム、２−メチル−１，３−ブタジエン−１−スルホン酸アンモニウム等が挙げられ、これらの中では２−メチル−１，３−ブタジエン−１−スルホン酸ナトリウム（イソプレンスルホン酸ナトリウム）、２−メチル−１，３−ブタジエン−１−スルホン酸カリウム、２−メチル−１，３−ブタジエン−１−スルホン酸アンモニウムが好ましい。
一般式［２］で表されるカルボキシル基を有する不飽和化合物としては、例えば、アクリル酸、メタクリル酸、クロトン酸、イソクロトン酸、ビニル酢酸、アンゲリカ酸、チグリン酸、マレイン酸、フマル酸、イタコン酸、シトラコン酸、メサコン酸、アコニット酸などを挙げることができる。
本発明において、（Ａ）スルホン酸基を有する共重合体は、一般式［１］で表される共役ジエンのスルホン化物１モルに対して、一般式［２］で表されるカルボキシル基を有する不飽和化合物０．１〜２０モルを共重合した共重合体であり、より好ましくは一般式［１］で表される化合物１モルに対して、一般式［２］で表される化合物１．５〜１２モルを共重合した共重合体である。一般式［１］で表される化合物１モルに対する一般式［２］で表される化合物の量が０．１モル未満であっても、２０モルを超えても、孔食を抑制する効果が十分に発現しないおそれがある。（Ａ）スルホン酸基を有する共重合体の重量平均分子量は、３，０００〜１５，０００であることが好ましく、５，０００〜１２，０００であることがより好ましい。なお、本発明において、重合体の分子量は、下記条件のゲルパーミエーションクロマトグラフィーにより測定し、ポリエチレングリコール標準試料に換算して求めた重量平均分子量である。
使用カラム：トーソーＴＳＫ−Ｇｅｌ Ｇ３０００ＰＷＸＬ及びＧ４０００ＰＷＸＬ
溶離液 ：０．２ｍｏｌｅ／Ｌ−ＮａＣｌ水溶液
検出器 ：ＲＩ
分離条件 ：カラム温度４０℃ 溶離液流量０．６ｍＬ／ｍｉｎ
サンプル ：０．４％ ２００μＬ
ＰＥＧ標準試料：ＧＬサイエンス社製のＰＥＧ標準物質（分子量百〜数万の１０種類）
本発明に用いる（Ａ）スルホン酸基を有する共重合体の製造方法に特に制限はなく、例えば、一般式［１］で表される共役ジエンのスルホン化物と一般式［２］で表されるカルボキシル基を有する不飽和化合物を水に溶解し、ラジカル重合開始剤を用いて水溶液重合することができる。
本発明においては、（Ａ）スルホン酸基を有する共重合体として、一般式［１］で表される共役ジエンのスルホン化物と一般式［２］で表されるカルボキシル基を有する不飽和化合物に加えて、さらに他の単量体を共重合した共重合体を用いることができる。
本発明に用いる炭素数４〜１０のアルケンとしては、例えば、１−ブテン、イソブチレン、１−ペンテン、３−メチル−１−ブテン、１−ヘキセン、３−メチル−１−ペンテン、４−メチル−１−ペンテン、１−ヘプテン、４−メチル−１−ヘキセン、５−メチル−１−ヘキセン、１−オクテン、５−メチル−１−ヘプテン、１−ノネン、１−デセンなどを挙げることができる。
本発明において、（Ｂ）疎水基を有する共重合体は、マレイン酸１モルに対して、炭素数４〜１０のアルケン０．８〜１．３モルを共重合した共重合体であり、より好ましくはマレイン酸１モルに対して、炭素数４〜１０のアルケン０．９５〜１．１モルを共重合した共重合体である。マレイン酸１モルに対するアルケンの量が０．８モル未満であっても、１．３モルを超えても、孔食を抑制する効果が十分に発現しないおそれがある。（Ｂ）疎水基を有する重合体の重量平均分子量は、４，０００〜５０，０００であることが好ましく、５，０００〜３５，０００であることがより好ましい。
本発明に用いる（Ｂ）疎水基を有する共重合体の製造方法に特に制限はなく、例えば、無水マレイン酸とアルケンを無溶媒で、又は、有機溶媒の存在下に、ラジカル重合開始剤を用いて重合し、得られた無水マレイン酸／アルケンの共重合体を加水分解することによって得ることができる。
本発明においては、（Ｂ）疎水基を有する共重合体として、マレイン酸と炭素数４〜１０のアルケンに加えて、さらに他の単量体を共重合した共重合体を用いることができる。
本発明に用いる（Ｃ）アゾール化合物は、ヘテロ原子２個以上を含む五員環を有する芳香族化合物であって、ヘテロ原子の少なくとも１個が窒素原子である化合物である。アゾール化合物としては、ピラゾール、イミダゾール、１，２，３−トリアゾール、１，２，４−トリアゾール、テトラゾール、オキサゾール、イソオキサゾール、チアゾール、イソチアゾール、オキサジアゾール、チアジアゾール、インダゾール、ベンゾイミダゾール、ベンゾトリアゾール、ベンゾオキサゾール、ベンゾイソオキサゾール、ベンゾチアゾール、トリルトリアゾールなどを挙げることができる。これらの中で、ベンゾトリアゾール及びトリルトリアゾールを好適に用いることができる。
本発明の金属の孔食抑制剤は、（Ａ）スルホン酸基を有する共重合体１重量部に対して、（Ｂ）疎水基を有する共重合体０．０５〜８重量部を含有することが好ましく、０．１〜４重量部を含有することがより好ましく、０．２５〜１．５重量部を含有することがさらに好ましい。（Ａ）スルホン酸基を有する共重合体１重量部に対する（Ｂ）疎水基を有する共重合体の量が０．０５重量部未満であっても、８重量部を超えても、孔食を抑制する効果が十分に発現しないおそれがある。
本発明の金属の孔食抑制剤は、（Ａ）スルホン酸基を有する共重合体１重量部に対して、（Ｃ）アゾール化合物０．００５〜０．１重量部を含有することが好ましく、０．００７〜０．０７重量部を含有することがより好ましい。（Ａ）スルホン酸基を有する共重合体１重量部に対する（Ｃ）アゾール化合物の量が０．００５重量部未満であると、孔食を抑制する効果が十分に発現しないおそれがある。（Ａ）スルホン酸基を有する共重合体１重量部に対する（Ｃ）アゾール化合物の量は、０．１重量部以下で十分な孔食抑制効果が発現し、通常は（Ａ）スルホン酸基を有する共重合体１重量部に対して０．１重量部を超える（Ｃ）アゾール化合物を含有させる必要はない。
本発明の金属の孔食抑制剤の剤型に特に制限はなく、例えば、（Ａ）スルホン酸基を有する共重合体、（Ｂ）疎水基を有する共重合体及び（Ｃ）アゾール化合物を含有する１剤型とすることができ、（Ａ）スルホン酸基を有する共重合体、（Ｂ）疎水基を有する共重合体及び（Ｃ）アゾール化合物の任意の２種と他の１種を組み合わせた２剤型とすることもでき、あるいは、（Ａ）スルホン酸基を有する共重合体、（Ｂ）疎水基を有する共重合体及び（Ｃ）アゾール化合物を別々に添加する３剤型とすることもできる。これらの中で、１剤型は、薬剤注入設備が簡略化され、添加濃度比も一定に保たれるので、好適に用いることができる。１剤にする際には、孔食抑制剤の安定化のために、水酸化アルカリや、鉱酸、有機酸などの酸類を添加することができる。また、防食効果を高めるために、リン酸塩、重合リン酸塩、ホスホン酸、亜鉛塩、アルミン酸塩、モリブデン酸塩などの防食剤を、本発明の孔食抑制剤に配合することができ、あるいは、これらの防食剤を水系に添加することもできる。
本発明の金属の孔食抑制方法においては、本発明の金属の孔食抑制剤を、（Ａ）スルホン酸基を有する共重合体、（Ｂ）疎水基を有する共重合体及び（Ｃ）アゾール化合物の合計として、水系に１〜１００ｍｇ／Ｌ、より好ましくは１０〜７０ｍｇ／Ｌ、さらに好ましくは１５〜５０ｍｇ／Ｌ添加する。（Ａ）スルホン酸基を有する共重合体、（Ｂ）疎水基を有する共重合体及び（Ｃ）アゾール化合物の合計の添加量が１ｍｇ／Ｌ未満であると、金属の孔食を抑制する効果が十分に発現しないおそれがある。（Ａ）スルホン酸基を有する共重合体、（Ｂ）疎水基を有する共重合体及び（Ｃ）アゾール化合物の合計の添加量が１００ｍｇ／Ｌを超えると、スルホン酸基を有する共重合体のキレート作用により防食皮膜の形成が遅くなったり、金属イオンと共重合体がキレート化合物を形成して着色するなどの障害が発生するおそれがある。
本発明において、（Ａ）スルホン酸基を有する共重合体と（Ｂ）疎水基を有する共重合体の混合物は、銅材質に対してキレート作用により防食皮膜の形成を阻害する場合がある。系内の銅材質が腐食して水中の全銅イオン濃度が高まると、鉄系金属の表面に溶解した銅イオンが電着して腐食を促進する。本発明においては、（Ｃ）アゾール化合物の添加により、銅の防食皮膜の形成が促進されるので、効果的に水系における金属の孔食が抑制されると推定される。
本発明の金属の孔食抑制剤及び孔食抑制方法によれば、一定期間の孔食の深さを３０〜６５％減少することができる。孔食深さの進行は、経験的に時間の１／３乗に比例するので、設備寿命ｔ（月）、設備の金属厚さｄ（ｍｍ）、初期１ヶ月間の孔食深さｋ（ｍｍ）の間に、ｔ＝ｄ３／ｋ３という関係が成り立ち、本発明により設備の寿命を３〜２０倍に延長することができる。The metal pitting inhibitor of the present invention is (A) an unsaturated compound having a carboxyl group represented by the general formula [2] with respect to 1 mol of a sulfonated compound of a conjugated diene represented by the general formula [1]. Sulfonic acid group-containing copolymer copolymerized with 0.1 to 20 moles, (B) Hydrophobic copolymerized with 0.8 to 1.3 moles of alkene having 4 to 10 carbon atoms per 1 mole of maleic acid. It contains a copolymer having a group and (C) an azole compound.
Examples of the sulfonated compound of the conjugated diene represented by the general formula [1] include sulfonic acid of the conjugated diene, and an alkali metal salt, alkaline earth metal salt, ammonium salt or amine salt thereof, and specific compounds thereof. Is, for example, 2-methyl-1,3-butadiene-1-sulfonic acid, 2-methyl-1,3-butadiene-3-sulfonic acid, 2-methyl-1,3-butadiene-4-sulfonic acid, 1, 3-pentadiene-1-sulfonic acid, 1,3-pentadiene-2-sulfonic acid, 1,3-pentadiene-3-sulfonic acid, 1,3-pentadiene-4-sulfonic acid, 2,3-dimethylbutadiene-1 -Sulfonic acid, 2-methyl-1,3-pentadiene-4-sulfonic acid, 3-methyl-1,3-pentadiene-1-sulfonic acid, 2-methyl-1,3-butadiene-1,3-disulfonic acid , 2-methyl-1,3-butadiene-1,4-disulfonic acid, sodium 2-methyl-1,3-butadiene-1-sulfonate (sodium isoprene sulfonate), 2-methyl-1,3-butadiene- Examples thereof include potassium 1-sulfonate and ammonium 2-methyl-1,3-butadiene-1-sulfonate. Among these, sodium 2-methyl-1,3-butadiene-1-sulfonate (sodium isoprenesulfonate) is included. ), potassium 2-methyl-1,3-butadiene-1-sulfonate, and ammonium 2-methyl-1,3-butadiene-1-sulfonate.
Examples of the unsaturated compound having a carboxyl group represented by the general formula [2] include acrylic acid, methacrylic acid, crotonic acid, isocrotonic acid, vinylacetic acid, angelic acid, tiglic acid, maleic acid, fumaric acid and itaconic acid. , Citraconic acid, mesaconic acid, aconitic acid and the like.
In the present invention, the copolymer (A) having a sulfonic acid group has a carboxyl group represented by the general formula [2] with respect to 1 mol of a sulfonated compound of the conjugated diene represented by the general formula [1]. It is a copolymer obtained by copolymerizing 0.1 to 20 mol of an unsaturated compound, and more preferably 1 mol of the compound represented by the general formula [1] to 1. mol of the compound represented by the general formula [2]. It is a copolymer obtained by copolymerizing 5 to 12 mol. If the amount of the compound represented by the general formula [2] is less than 0.1 mol or more than 20 mol relative to 1 mol of the compound represented by the general formula [1], the effect of suppressing pitting corrosion is obtained. It may not be sufficiently expressed. The weight average molecular weight of the (A) sulfonic acid group-containing copolymer is preferably 3,000 to 15,000, and more preferably 5,000 to 12,000. In the present invention, the molecular weight of the polymer is a weight average molecular weight measured by gel permeation chromatography under the following conditions and converted into a polyethylene glycol standard sample.
Columns used: Toso TSK-Gel G3000PWXL and G4000PWXL
Eluent: 0.2 mole/L-NaCl aqueous solution Detector: RI
Separation conditions: Column temperature 40° C. Eluent flow rate 0.6 mL/min
Sample: 0.4% 200 μL
PEG standard sample: PEG standard material manufactured by GL Science Co., Ltd. (10 kinds with a molecular weight of 100 to tens of thousands)
The method for producing the (A) sulfonic acid group-containing copolymer used in the present invention is not particularly limited, and is represented by, for example, a sulfonated product of a conjugated diene represented by the general formula [1] and a general formula [2]. An unsaturated compound having a carboxyl group can be dissolved in water and polymerized in an aqueous solution using a radical polymerization initiator.
In the present invention, the copolymer (A) having a sulfonic acid group is a sulfonated product of a conjugated diene represented by the general formula [1] and an unsaturated compound having a carboxyl group represented by the general formula [2]. In addition, a copolymer obtained by copolymerizing another monomer can be used.
Examples of the alkene having 4 to 10 carbon atoms used in the present invention include 1-butene, isobutylene, 1-pentene, 3-methyl-1-butene, 1-hexene, 3-methyl-1-pentene and 4-methyl-. 1-pentene, 1-heptene, 4-methyl-1-hexene, 5-methyl-1-hexene, 1-octene, 5-methyl-1-heptene, 1-nonene, 1-decene and the like can be mentioned.
In the present invention, the copolymer (B) having a hydrophobic group is a copolymer obtained by copolymerizing 0.8 to 1.3 mol of an alkene having 4 to 10 carbon atoms with 1 mol of maleic acid, and Preferred is a copolymer obtained by copolymerizing 0.95 to 1.1 mol of an alkene having 4 to 10 carbon atoms with 1 mol of maleic acid. If the amount of the alkene is less than 0.8 mol or more than 1.3 mol with respect to 1 mol of maleic acid, the effect of suppressing pitting corrosion may not be sufficiently exhibited. The weight average molecular weight of the polymer (B) having a hydrophobic group is preferably 4,000 to 50,000, and more preferably 5,000 to 35,000.
There is no particular limitation on the method for producing the (B) copolymer having a hydrophobic group used in the present invention. For example, a maleic anhydride and an alkene are used without a solvent or in the presence of an organic solvent, a radical polymerization initiator is used. It can be obtained by hydrolyzing the obtained maleic anhydride/alkene copolymer.
In the present invention, as the copolymer (B) having a hydrophobic group, a copolymer obtained by copolymerizing maleic acid and an alkene having 4 to 10 carbon atoms and further another monomer can be used.
The (C) azole compound used in the present invention is an aromatic compound having a five-membered ring containing two or more hetero atoms, and at least one of the hetero atoms is a nitrogen atom. Examples of the azole compound include pyrazole, imidazole, 1,2,3-triazole, 1,2,4-triazole, tetrazole, oxazole, isoxazole, thiazole, isothiazole, oxadiazole, thiadiazole, indazole, benzimidazole and benzotriazole. , Benzoxazole, benzisoxazole, benzothiazole, tolyltriazole, and the like. Among these, benzotriazole and tolyltriazole can be preferably used.
The metal pitting inhibitor of the present invention contains 0.05 to 8 parts by weight of the copolymer (B) having a hydrophobic group with respect to 1 part by weight of the copolymer (A) having a sulfonic acid group. Is more preferable, 0.1 to 4 parts by weight is more preferable, and 0.25 to 1.5 parts by weight is further preferable. If the amount of the (B) copolymer having a hydrophobic group is less than 0.05 parts by weight or more than 8 parts by weight relative to 1 part by weight of the (A) copolymer having a sulfonic acid group, pitting corrosion is caused. There is a possibility that the suppressing effect may not be sufficiently exhibited.
The metal pitting inhibitor of the present invention preferably contains 0.005 to 0.1 part by weight of the (C) azole compound with respect to 1 part by weight of the copolymer (A) having a sulfonic acid group, It is more preferable to contain 0.007 to 0.07 parts by weight. If the amount of the (C) azole compound is less than 0.005 parts by weight relative to 1 part by weight of the copolymer having a sulfonic acid group (A), the effect of suppressing pitting corrosion may not be sufficiently exhibited. The amount of the (C) azole compound with respect to 1 part by weight of the copolymer (A) having a sulfonic acid group is 0.1 parts by weight or less, and a sufficient pitting corrosion inhibitory effect is exhibited, and the sulfonic acid group It is not necessary to contain more than 0.1 part by weight of the (C) azole compound with respect to 1 part by weight of the copolymer.
The dosage form of the metal pitting inhibitor of the present invention is not particularly limited, and includes, for example, (A) a copolymer having a sulfonic acid group, (B) a copolymer having a hydrophobic group, and (C) an azole compound. Can be made into a one-component type, and (A) a copolymer having a sulfonic acid group, (B) a copolymer having a hydrophobic group, and (C) an arbitrary two kinds of an azole compound are combined with another one kind. It may be a two-component type or a three-component type in which (A) a sulfonic acid group-containing copolymer, (B) a hydrophobic group-containing copolymer and (C) an azole compound are added separately. You can also Among them, the one-dose type can be preferably used because the drug injection facility is simplified and the addition concentration ratio is kept constant. When forming a single agent, an acid such as an alkali hydroxide or a mineral acid or an organic acid can be added to stabilize the pitting corrosion inhibitor. Further, in order to enhance the anticorrosion effect, an anticorrosive agent such as phosphate, polymerized phosphate, phosphonic acid, zinc salt, aluminate, molybdate, etc. can be added to the pitting inhibitor of the present invention. Alternatively, these anticorrosive agents can be added to the water system.
In the metal pitting corrosion inhibiting method of the present invention, the metal pitting corrosion inhibiting agent of the present invention comprises: (A) a sulfonic acid group-containing copolymer, (B) a hydrophobic group-containing copolymer, and (C) an azole. As a total of compounds, 1 to 100 mg/L, more preferably 10 to 70 mg/L, further preferably 15 to 50 mg/L is added to the aqueous system. When the total amount of the (A) sulfonic acid group-containing copolymer, (B) hydrophobic group-containing copolymer, and (C) azole compound added is less than 1 mg/L, the effect of suppressing metal pitting corrosion is achieved. May not be sufficiently expressed. When the total amount of the (A) sulfonic acid group-containing copolymer, (B) hydrophobic group-containing copolymer, and (C) azole compound added exceeds 100 mg/L, the sulfonic acid group-containing copolymer There is a possibility that the formation of the anticorrosion film may be delayed due to the chelating action, or a disorder may occur such that the metal ion and the copolymer form a chelate compound to cause coloration.
In the present invention, the mixture of the (A) sulfonic acid group-containing copolymer and the (B) hydrophobic group-containing copolymer may inhibit the formation of the anticorrosion coating due to the chelating action on the copper material. When the copper material in the system corrodes and the total copper ion concentration in water increases, the copper ions dissolved on the surface of the iron-based metal are electrodeposited to promote corrosion. In the present invention, the addition of the (C) azole compound promotes the formation of a copper anticorrosion coating, and is therefore presumed to effectively suppress the metal pitting corrosion in the water system.
According to the metal pitting corrosion inhibitor and the pitting corrosion inhibiting method of the present invention, the pitting corrosion depth for a certain period can be reduced by 30 to 65%. Since the progress of the pitting depth is empirically proportional to the 1/3 power of time, the equipment life t (month), the metal thickness d (mm) of the equipment, and the pitting depth k ( mm), the relationship of t=d 3 /k 3 is established, and the life of the equipment can be extended 3 to 20 times by the present invention.
以下に、実施例を挙げて本発明をさらに詳細に説明するが、本発明はこれらの実施例によりなんら限定されるものではない。
なお、実施例及び比較例においては、下記の重合体（すべてナトリウム塩）を用いた。
（Ａ）スルホン酸基を有する共重合体
重合体Ｄ：イソプレンスルホン酸／アクリル酸共重合体、モル比２０：８０、重量平均分子量７，５００。
重合体Ｅ：イソプレンスルホン酸／アクリル酸共重合体、モル比１０：９０、重量平均分子量９，０００。
重合体Ｇ：イソプレンスルホン酸／アクリル酸共重合体、モル比１０：９０、重量平均分子量２３，０００。
重合体Ｈ：イソプレンスルホン酸／アクリル酸／メタクリル酸２−ヒドロキシエチル共重合体、モル比２０：６５：１５、重量平均分子量６，５００。
（Ｂ）疎水性基を有する共重合体
重合体Ａ：マレイン酸／イソブチレン共重合体、モル比５０：５０、重量平均分子量１４，０００。
重合体Ｂ：マレイン酸／１−ヘキセン共重合体、モル比４５：５５、重量平均分子量２０，０００。
重合体Ｃ：マレイン酸／１−ペンテン共重合体、モル比５３：４７、重量平均分子量６，５００。
（Ｄ）その他の重合体
重合体Ｆ：ポリマレイン酸、重量平均分子量６００。
重合体Ｉ：マレイン酸／２−アクリルアミド−２−メチルプロパンスルホン酸共重合体、モル比８０：２０、重量平均分子量２，０００。
また、Ｆｉｇ．１に示す通水試験装置を用いて、孔食抑制効果を評価した。水量５２Ｌのタンク１から、ポンプ２により試験水を送り、流速０．５ｍ／ｓで炭素鋼管３、炭素鋼管４及び銅管５を通過したのち、腐食計６を経由してタンクに循環した。ｐＨ８．８、Ｍアルカリ度３００ｍｇＣａＣＯ３／Ｌ、カルシウム硬度３００ｍｇＣａＣＯ３／Ｌ、シリカ濃度１００ｍｇＳｉＯ２／Ｌの試験水を、タンクに６３４ｍＬ／ｈ供給し、過剰の水をタンクより溢流させた。試験水の滞留時間は、８２時間である。試験水の温度を３０℃に調整し、タンク底部の曝気管から１０Ｌ／ｍｉｎの空気を送って曝気した。３０日間連続して通水したのち、炭素鋼管３で最大孔食深さ（ｍｍ／３０日）を測定した。また、腐食計により、１日１回、分極抵抗法で炭素鋼と銅の腐食速度（ｍｄｄ＝ｍｇ・ｄｍ−２・ｄａｙ−１）を測定し、３０日間の平均値を算出した。
実施例１
試験水に、（Ａ）重合体Ｄ３２ｍｇ／Ｌ、（Ｂ）重合体Ａ８ｍｇ／Ｌ及び（Ｃ）ベンゾトリアゾール１ｍｇ／Ｌを添加して試験を行った。炭素鋼の最大孔食深さは０．２１ｍｍ／３０日であり、炭素鋼の腐食速度は３．２ｍｄｄ、銅の腐食速度は０．９ｍｄｄであった。
実施例２
試験水に、（Ａ）重合体Ｄ２４ｍｇ／Ｌ、（Ｂ）重合体Ａ１６ｍｇ／Ｌ及び（Ｃ）ベンゾトリアゾール１ｍｇ／Ｌを添加して試験を行った。
実施例３
試験水に、（Ａ）重合体Ｄ２０ｍｇ／Ｌ、（Ｂ）重合体Ａ２０ｍｇ／Ｌ及び（Ｃ）ベンゾトリアゾール０．５ｍｇ／Ｌとトリルトリアゾール０．５ｍｇ／Ｌを添加して試験を行った。
実施例４〜１０
試験水に、第１表に示す（Ａ）スルホン酸基を有する共重合体、（Ｂ）疎水基を有する共重合体及び（Ｃ）アゾール化合物を添加して試験を行った。
比較例１
試験水に、（Ｂ）重合体Ａ４０ｍｇ／Ｌ及び（Ｃ）ベンゾトリアゾール０．０５ｍｇ／Ｌを添加して試験を行った。炭素鋼の最大孔食深さは０．３０ｍｍ／３０日であり、炭素鋼の腐食速度は３．６ｍｄｄ、銅の腐食速度は１．６ｍｄｄであった。
比較例２〜８
試験水に、第１表に示す化合物を添加して試験を行った。
実施例１〜１０及び比較例１〜８の結果を、第１表に示す。
これに対して、（Ｂ）マレイン酸／イソブチレンの共重合体と（Ｃ）ベンゾトリアゾールを添加した比較例１、（Ａ）イソプレンスルホン酸／アクリル酸の共重合体のみを添加した比較例２、（Ｂ）マレイン酸／アルケンの共重合体のみを添加した比較例３、（Ｄ）ポリマレイン酸と（Ｂ）マレイン酸／イソブチレンの共重合体と（Ｃ）トリルトリアゾールを添加した比較例４、（Ａ）イソプレンスルホン酸／アクリル酸の共重合体と（Ｂ）マレイン酸／１−ヘキセンの共重合体を添加した比較例５、（Ａ）イソプレンスルホン酸／アクリル酸／メタクリル酸２−ヒドロキシエチルの共重合体と（Ｂ）マレイン酸／１−ヘキセンの共重合体を添加した比較例６、（Ｄ）マレイン酸／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と（Ｂ）マレイン酸／イソブチレンの共重合体を添加した比較例７、（Ｂ）マレイン酸／１−ヘキセンの共重合体のみを添加した比較例８では、炭素鋼の最大孔食の深さが０．３０〜０．４８ｍｍ／３０日で、孔食抑制効果はほとんど発現していない。また、炭素鋼の腐食速度が３．４〜６．２ｍｄｄ、銅の腐食速度が１．５〜２．２ｍｄｄで、銅に対する腐食抑制効果が弱い。アゾール化合物を添加していない系では銅が腐食し、溶出した銅イオンが炭素鋼の表面に電着し、炭素鋼の腐食が加速されたと考えられる。Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to these Examples.
The following polymers (all sodium salts) were used in Examples and Comparative Examples.
(A) Copolymer Having Sulfonic Acid Group Polymer D: isoprenesulfonic acid/acrylic acid copolymer, molar ratio 20:80, weight average molecular weight 7,500.
Polymer E: isoprene sulfonic acid/acrylic acid copolymer, molar ratio 10:90, weight average molecular weight 9,000.
Polymer G: isoprene sulfonic acid/acrylic acid copolymer, molar ratio 10:90, weight average molecular weight 23,000.
Polymer H: isoprene sulfonic acid/acrylic acid/2-hydroxyethyl methacrylate copolymer, molar ratio 20:65:15, weight average molecular weight 6,500.
(B) Copolymer having hydrophobic group Polymer A: maleic acid/isobutylene copolymer, molar ratio 50:50, weight average molecular weight 14,000.
Polymer B: maleic acid/1-hexene copolymer, molar ratio 45:55, weight average molecular weight 20,000.
Polymer C: maleic acid/1-pentene copolymer, molar ratio 53:47, weight average molecular weight 6,500.
(D) Other polymers Polymer F: polymaleic acid, weight average molecular weight 600.
Polymer I: Maleic acid/2-acrylamido-2-methylpropanesulfonic acid copolymer, molar ratio 80:20, weight average molecular weight 2,000.
In addition, FIG. The water penetration test apparatus shown in 1 was used to evaluate the pitting corrosion inhibiting effect. Test water was sent from the tank 1 having a water amount of 52 L by the pump 2, passed through the carbon steel pipe 3, the carbon steel pipe 4 and the copper pipe 5 at a flow rate of 0.5 m/s, and then circulated to the tank via the corrosion meter 6. Test water having a pH of 8.8, M alkalinity of 300 mgCaCO 3 /L, calcium hardness of 300 mgCaCO 3 /L, and silica concentration of 100 mgSiO 2 /L was supplied to the tank at 634 mL/h, and excess water was overflowed from the tank. The residence time of the test water is 82 hours. The temperature of the test water was adjusted to 30° C., and 10 L/min of air was sent from the aeration pipe at the bottom of the tank for aeration. After continuously passing water for 30 days, the maximum pitting depth (mm/30 days) was measured with the carbon steel pipe 3. Moreover, the corrosion rate (mdd=mg*dm <-2 >day < -1 >) of carbon steel and copper was measured by the polarization resistance method once a day with the corrosometer, and the average value for 30 days was calculated.
Example 1
A test was conducted by adding (A) polymer D 32 mg/L, (B) polymer A 8 mg/L and (C) benzotriazole 1 mg/L to test water. The maximum pitting depth of carbon steel was 0.21 mm/30 days, the corrosion rate of carbon steel was 3.2 mdd, and the corrosion rate of copper was 0.9 mdd.
Example 2
The test was conducted by adding (A) polymer D 24 mg/L, (B) polymer A 16 mg/L and (C) benzotriazole 1 mg/L to test water.
Example 3
The test was conducted by adding (A) polymer D 20 mg/L, (B) polymer A 20 mg/L, and (C) benzotriazole 0.5 mg/L and tolyltriazole 0.5 mg/L to the test water.
Examples 4-10
The test was carried out by adding (A) a copolymer having a sulfonic acid group, (B) a copolymer having a hydrophobic group and (C) an azole compound shown in Table 1 to the test water.
Comparative Example 1
The test was conducted by adding 40 mg/L of the polymer A (B) and 0.05 mg/L of the benzotriazole (C) to the test water. The maximum pitting depth of carbon steel was 0.30 mm/30 days, the corrosion rate of carbon steel was 3.6 mdd, and the corrosion rate of copper was 1.6 mdd.
Comparative Examples 2-8
The test was conducted by adding the compounds shown in Table 1 to the test water.
The results of Examples 1 to 10 and Comparative Examples 1 to 8 are shown in Table 1.
On the other hand, Comparative Example 1 in which (B) a maleic acid/isobutylene copolymer and (C) benzotriazole were added, (A) a comparative example 2 in which only an isoprenesulfonic acid/acrylic acid copolymer was added, (B) Comparative Example 3 in which only a maleic acid/alkene copolymer was added, (D) Polymaleic acid and (B) a maleic acid/isobutylene copolymer, and (C) Tolyltriazole in Comparative Example 4, ( Comparative Example 5 in which A) isoprene sulfonic acid/acrylic acid copolymer and (B) maleic acid/1-hexene copolymer were added, and (A) isoprene sulfonic acid/acrylic acid/2-hydroxyethyl methacrylate Comparative Example 6 in which a copolymer and a copolymer of (B) maleic acid/1-hexene were added, a copolymer of (D) maleic acid/2-acrylamido-2-methylpropanesulfonic acid and (B) maleic acid In Comparative Example 7 in which the copolymer of //isobutylene was added and Comparative Example 8 in which only the copolymer of (B) maleic acid/1-hexene was added, the maximum pitting depth of carbon steel was 0.30 to 0. At 48 mm/30 days, almost no pitting corrosion inhibitory effect is exhibited. Further, the corrosion rate of carbon steel is 3.4 to 6.2 mdd and the corrosion rate of copper is 1.5 to 2.2 mdd, and the effect of suppressing corrosion on copper is weak. It is considered that copper was corroded in the system in which the azole compound was not added, and the eluted copper ions were electrodeposited on the surface of the carbon steel, and the corrosion of the carbon steel was accelerated.
本発明の金属の孔食抑制剤及び孔食抑制方法によれば、開放循環冷却水系において、リン化合物や亜鉛塩などの重金属塩を用いることなく、炭素鋼の孔食の進行を抑制し、熱交換器などの水と接する設備の寿命を効果的に延長することができる。 According to the metal pitting corrosion inhibitor and the pitting corrosion inhibition method of the present invention, in the open circulation cooling water system, without using heavy metal salts such as phosphorus compounds and zinc salts, the progress of pitting corrosion of carbon steel is suppressed, and It is possible to effectively extend the life of facilities such as exchangers that come into contact with water.
【０００３】
延長することができる金属の孔食抑制剤及び孔食抑制方法を提供することを目的としてなされたものである。
【発明の開示】
本発明者らは、上記の課題を解決すべく鋭意研究を重ねた結果、（Ａ）共役ジエンのスルホン化物とカルボキシル基を有する不飽和化合物との共重合体、（Ｂ）マレイン酸とアルケンとの共重合体及び（Ｃ）アゾール化合物を含有する薬剤を水系に添加することにより、孔食の進行を効果的に抑制し得ることを見いだし、この知見に基づいて本発明を完成するに至った
すなわち、本発明は、
（１）（Ａ）一般式［１］で表される共役ジエンのスルホン化物１モルに対して、一般式［２］で表されるカルボキシル基を有する不飽和化合物０．１〜２０モルを共重合したスルホン酸基を有する共重合体、（Ｂ）マレイン酸１モルに対して、炭素数４〜１０のアルケン０．８〜１．３モルを共重合した疎水基を有する共重合体、並びに（Ｃ）ベンゾトリアゾール及び／又はトリルトリアゾールを含有することを特徴とする金属の孔食抑制剤、
The object of the present invention is to provide a metal pitting corrosion inhibitor that can be extended and a pitting corrosion inhibition method.
DISCLOSURE OF THE INVENTION
As a result of intensive studies to solve the above problems, the present inventors have found that (A) a copolymer of a conjugated diene sulfonate and an unsaturated compound having a carboxyl group, and (B) maleic acid and an alkene. It was found that the progress of pitting corrosion can be effectively suppressed by adding a drug containing the copolymer of (1) and the (C) azole compound to an aqueous system, and the present invention has been completed based on this finding. That is, the present invention is
(1) (A) 0.1-20 mol of an unsaturated compound having a carboxyl group represented by the general formula [2] is used per 1 mol of a sulfonated compound of a conjugated diene represented by the general formula [1]. A copolymer having a polymerized sulfonic acid group, (B) a copolymer having a hydrophobic group obtained by copolymerizing 0.8 to 1.3 mol of an alkene having 4 to 10 carbon atoms with 1 mol of maleic acid, and (C) A pitting corrosion inhibitor for a metal, which comprises benzotriazole and/or tolyltriazole,
【０００４】
は炭素数１〜８のアルキル基であり、ｍは０〜８であり、Ｍは水素原子、アルカリ金属、アルカリ土類金属原子、アンモニウム基又はアミノ基である。）、
（２）（Ａ）スルホン酸基を有する共重合体１重量部に対して、（Ｂ）疎水基を有する共重合体０．０５〜８重量部及び（Ｃ）ベンゾトリアゾール及び／又はトリルトリアゾール０．００５〜０．１重量部を含有する（１）記載の金属の孔食抑制剤、及び、
（３）（１）又は（２）記載の金属の孔食抑制剤を、（Ａ）スルホン酸基を有する共重合体、（Ｂ）疎水基を有する共重合体及び（Ｃ）ベンゾトリアゾール及び／又はトリルトリアゾールの合計として、水系に１〜１００ｍｇ／Ｌ添加することを特徴とする金属の孔食抑制方法、を提供するものである。
【図面の簡単な説明】
Ｆｉｇ．１は実施例で用いた通水試験装置の系統図である。図中、符号１はタンク、２はポンプ、３は炭素鋼管、４は炭素鋼管、５は銅管、６は腐食計を表す。
【発明を実施するための最良の形態】
本発明の金属の孔食抑制剤は、（Ａ）一般式［１］で表される共役ジエンのスルホン化物１モルに対して、一般式［２］で表されるカルボキシル基を有する不飽和化合物０．１〜２０モルを共重合したスルホン酸基を有する共重合体、（Ｂ）マレイン酸１モルに対して、炭素数４〜１０のアルケン０．８〜１．３モルを共重合した疎水基を有する共重合体及び（Ｃ）アゾール化合物を含有する。
Is an alkyl group having 1 to 8 carbon atoms, m is 0 to 8 and M is a hydrogen atom, an alkali metal, an alkaline earth metal atom, an ammonium group or an amino group. ),
(2) 0.05 to 8 parts by weight of (B) copolymer having a hydrophobic group and (C) benzotriazole and/or tolyltriazole to 1 part by weight of (A) sulfonic acid group-containing copolymer A metal pitting inhibitor according to (1), which contains 0.005 to 0.1 part by weight;
(3) The metal pitting inhibitor as described in (1) or (2), (A) a copolymer having a sulfonic acid group, (B) a copolymer having a hydrophobic group, and (C) benzotriazole and/ Alternatively, the present invention provides a method for suppressing pitting corrosion of metal, which comprises adding 1 to 100 mg/L to a water system as a total of tolyltriazole.
[Brief description of drawings]
Fig. 1 is a system diagram of the water flow test apparatus used in the examples. In the figure, reference numeral 1 is a tank, 2 is a pump, 3 is a carbon steel tube, 4 is a carbon steel tube, 5 is a copper tube, and 6 is a corrosion meter.
BEST MODE FOR CARRYING OUT THE INVENTION
The metal pitting inhibitor of the present invention is (A) an unsaturated compound having a carboxyl group represented by the general formula [2] with respect to 1 mol of a sulfonated compound of a conjugated diene represented by the general formula [1]. Sulfonic acid group-containing copolymer copolymerized with 0.1 to 20 moles, (B) Hydrophobic copolymerized with 0.8 to 1.3 moles of alkene having 4 to 10 carbon atoms per 1 mole of maleic acid. It contains a copolymer having a group and (C) an azole compound.
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| PCT/JP2005/011406 WO2005123981A1 (en) | 2004-06-17 | 2005-06-15 | Pitting corrosion inhibitor for metal and method of inhibition |
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| WO2014136012A1 (en) * | 2013-03-04 | 2014-09-12 | Schlumberger Technology B.V. | Corrosion inhibition |
| GB2529723B (en) | 2014-09-01 | 2017-04-05 | Schlumberger Holdings | A method of corrosion inhibition of metal |
| CN105039995B (en) * | 2015-07-09 | 2017-08-29 | 潍坊友容实业有限公司 | A kind of special anti-incrustation corrosion inhibitor of salt-soda soil salt discharge hidden pipe and preparation method thereof |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5392349A (en) * | 1977-01-25 | 1978-08-14 | Organo Kk | Metal anticorrosive |
| JPH0433868B2 (en) * | 1985-09-25 | 1992-06-04 | Kurita Water Ind Ltd | |
| JPH0957295A (en) * | 1995-08-21 | 1997-03-04 | Kurita Water Ind Ltd | Iron-component dispersing agent for water system |
| JP2625914B2 (en) * | 1988-06-29 | 1997-07-02 | 日本合成ゴム株式会社 | Water treatment agent |
-
2005
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5392349A (en) * | 1977-01-25 | 1978-08-14 | Organo Kk | Metal anticorrosive |
| JPH0433868B2 (en) * | 1985-09-25 | 1992-06-04 | Kurita Water Ind Ltd | |
| JP2625914B2 (en) * | 1988-06-29 | 1997-07-02 | 日本合成ゴム株式会社 | Water treatment agent |
| JPH0957295A (en) * | 1995-08-21 | 1997-03-04 | Kurita Water Ind Ltd | Iron-component dispersing agent for water system |
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