Issued Jul. 1, 1987 - threebond.co.jp

1 1 Three Bond Technical News Issued Jul. 1, 1987 Volatile corrosion Inhibitor (VCI)1. IntroductionTrade dispute by export surplus has come up in the newspaper. Trading, especially export, is essential to Japan economy,whereas it is said that economical loss caused by corrosion in the export activity is about 2,000,000,000,000 at Three Bond have released a variety of volatile corrosion inhibitors as ThreeBond 1870 series when we considered thesecircumstances. Volatile corrosion inhibitors have been codified technically, but they took an auxiliary part only in rustprevention due to their relatively shallow this issue, we will provide you with VCI's features that it should be the mainstream in the future rust prevention packaging,and also introduce a new method as Introduction .. 12. What is Volatile corrosion Inhibitor (VCI)?.. 23. Positioning of Volatile corrosion 24.

2 Shape of Volatile corrosion Inhibitors .. 25. Type of Volatile corrosion 26. Typical Volatile corrosion Inhibitors .. 27. Structure of Typical Volatile corrosion 38. Structure of Typical Volatile corrosion 39. corrosion Inhibitor Mechanism of Volatile 410. corrosion Inhibition Effect of Volatile 511. Toxicity of Volatile corrosion 612. General Considerations on Applying VolatileCorrosion Inhibitor (VCI) .. 613. Three Bond's Volatile corrosion Inhibitors .. 714. Rust Prevention Effect for Three Bond's VolatileCorrosion Inhibitors .. 715. How to Confirm the Effectiveness of VolatileCorrosion Inhibitors .. 8(1) Present situation and necessity of 8(2) About indicator technology .. 8(3) Components to develop color .. 8(4) Chemical mechanism .. 8(5) Quantitation of the color development degree. 8(6) Relationship between amount of volatilization involatile corrosion inhibitors and color 9(7) Relationship among amount of volatile corrosioninhibitor vaporization (%), color developmentdegree and rust prevention capability.

3 9(8) Discussion .. 10(9) Summary .. 1016. Conclusion .. 10 Contents22. What is Volatile corrosion Inhibitor (VCI)?Volatile corrosion inhibitor is referred to metal corrosioninhibitor that has a volatile property at normaltemperature regardless of solid or volatile corrosion inhibitor is a compound ormixture that is vaporized slowly at normal temperaturesuch as nectarine, camphor, paradichlorobenzene that areused in a home as a mothproofing agent. The vaporizedgas can prevent metal corrosion , that absorbs to ametallic surface chemically and physically and reactswith that surface or that forms an atmosphere thatprevents metal corrosion inhibitor is often called as VCI(Volatile corrosion Inhibitor) or VRI (Volatile RustInhibitor).3. Positioning of Volatile corrosion InhibitorsVolatile corrosion Inhibitor is classified into packaging category in the rust prevention or rustprevention field as apparently shown in Figure 1.

4 Classification of Rust Prevention or Corro-sion Prevention Agents4. Shape of Volatile corrosion Inhibi-torsProducts that use volatile corrosion inhibitors are asfollows:(1) Powder(6) Device(2) Tablet(7) Emitter(3) Rust-inhibiting oil(8) Tape(4) Water-soluble rust inhibitor(9) Film(5) Rust-inhibiting paper(10) Others5. Type of Volatile corrosion Inhibi-tors(1) Volatile corrosion Inhibitors for Steel- Nitrite of amines- Carboxylate of amines- Chromate of amines- Ester of carboxylic acid- These mixtureIt often uses a quick volatile benzoic acidmonoethanolamine salt together for steel.(2) Volatile Rust Inhibitor for Coppers and CopperAlloys- Hetero cyclic compoundsTriazole ringPyrole ringPyrazole ringThiazole ringCompounds with imidazole ring- Thiourea ring- Compounds with mercapto group6. Typical Volatile corrosion Inhibi-tors1 BTA:Benzo triazole2 TTA :Tolyl triazole (Methyl benzotriazole) 3 DICHAN :Dicyclohexyl ammonium nitrite4 DICHA SA :Dicyclohexyl ammonium salicylate5 MEA BA :Monoethanolamine benzoate6 DICHA BA :Dicyclohexyl ammonium benzoate7 DIPA BA :Diisopropyl ammonium benzoate 8 DIPAN :Diisopropyl ammonium nitrite9 CHC :Cyclohexylamine carbamate10 NITAN :Nitro naphthalene ammonium nitriteRust Prevention / corrosion Prevention AgentsRust-Prevention LubricantThreeBond 1800 series, PaintPando 614A, Surface ProcessPainting, Thermal Spraying, corrosion Inhibitors, CHA BA :Cyclohexylamine benzoate12 DICHA CHC :Dicyclohexyl ammonium cyclohexanecarboxylate13 CHA CHC :Cyclohexylamine cyclohexane carboxylate14 DICHA AA.

5 Dicyclohexyl ammonium acrylate15 CHA AA :Cyclohexylamine acrylate16 Others7. Structure of Typical Volatile Corro-sion InhibitorsFigure 2. Structure of Typical Volatile corrosion Inhibitors8. Structure of Typical Volatile corrosion InhibitorsTable 1. Rust Prevention Effect for Various MetalsRust Prevention AgentsBTADICHANDICHA SAMEA BADICHA BADIPA BACHA BADICHA CHCCHA CHCDICHA AACHA AAMetalsCopper Phosphor bronze Brass Aluminum corrosion resistant aluminum Zinc die casting Duralumin Magnesium alloy Alumite Gloss chrome plating Hard chrome plating Gloss zinc chrome plating Gloss zinc plating Hot-dip zinc plating Silver plating Nickel plating Solder plating Tin plating Cadmium plating Evaluation : It has rust prevention capability, and is excellent rust prevention capability.

6 : It has weak rust prevention capability compared to others. : It has no rust prevention capability, or adverse effect. : It has no rust prevention capability, or adverse effect (accelerated corrosion ).Condition Temperature: 50 C, Humidity: 90RH%, Period: 70 days49. corrosion Inhibitor Mechanism of Volatile corrosion Inhibitors(1) For Steelsa. Nitrite (DICHAN)Figure 3. NitriteIf moisture in the air is condensed into a metallic surface,this slowly vaporized DICHAN is dissolved into thecondensation water to prevent oxygen and liquid waterthat react with a metal from Carboxylate of aminesIn this case, carboxylate of amines was disaggregatedinto amine and carboxylic acid, and they wererecombined in a metal surface back into the carboxylateof amines, which prevents metal Mixed systemEven corrosion inhibitors without characteristics tovaporize alone are hydrolyzed and evaporated in mixturesystem by absorbing atmospheric case of sodium nitrite and urea(2)

7 Coppers and Copper AlloysCorrosion inhibition mechanism, inclulding BTA andTTA, for coppers and copper alloys is considered not dueto simple absorption or forming complex compoundsfilms, but due to forming benzotriazole copper saltcoating by reacting as follows:Cu + O2 + 2C6H4N2 NH (C6H4N2 N)2 Cu + H2 OOn the other hand, polymer-like compounds are formedby copper ionic states shown in Figure 4 and Figure of protective films shown in Figure 4 andFigure 5 is about 50 to 2000 , and they are a multiplefilm composed by Cu2O and Cu-BTA, as well as a filmby simple 4. In case of CuI BTAF igure 5. In case of CuII BTANNHOOHV aporization state of DICHANNH-HNO2 + H2 ONH2 + H2NO2NH2+ + OH + H+ + NO2Fe + 2(C6H11)2NH-HNO2[(C6H11)2NH]2 Fe (NO2)2 + H2 Carboxylate of aminesDisaggregatedAmine carboxylic acidCarboxylate of aminesRecombined with a metallic2NH3 + 2 HNO2CO(NH2)2 + 2 NaNO2 + 2H2 2NH4NO2 + Na2CO3 NNNCuCuNNNCuCuNNNCuI BTACuCuCuCuCuCuCuII BTA510.

8 corrosion Inhibition Effect of Vola-tile corrosion Inhibitors(1) Effect in SolutionA solution that volatile corrosion inhibitors are dissolvedobtains rust prevention effects. Results that steel testpieces grinded as shown in Figure 6 are examined in eachconcentration are shown in Table 2. From this result,valid threshold concentration in distilled water ofDICHAN is found as or Test piece: SAE-1020 Temperature: CTime: 500hFigure 6. corrosion prevention capability test equipment for solutions(2) Effect in Gas PhaseIt is clear that volatile corrosion inhibitors should showrust prevention effects in gas phase, but every corrosionprevention materials don't show the effects effect variation is great due to steam pressure andthe like, and the typical examples are shown in Table 3.(Criteria in volatile corrosion inhibitors)On the other hand, rust prevention effects in gas phasegreatly depend on minimum requirements orconcentrations along with initial effects.

9 The results areshown in Table 4. As shown in the table, the minimumrequirement is found 5mg/l or so as a rough 4. Minimum requirements of typical volatile corrosion inhibitors(20 1 C, 20h)(Criteria and indication are same as Table 3.)Table 2. corrosion prevention effects in DICHAN distilled water solutionTest pieceABCC oncentration(wt%)B1B20 : Rusting : Slightly Rusting : Complete corrosion PreventedB2B1 ACTable 3. Initial effect in the typical volatile corrosion inhibitors (20 1 C)Time (h)DICHANDIPANCHC1/4 1/2 1 2 3 4 5 16 20 CriteriaIndicationResultNo rusting; Passed in specified codes completely PassedSome rusting; Rejected in specified codes, but effects are recognized definitely RejectedRusting but a little effects are recognized compared with blank tests RejectedRusting same as blank tests; no effects are recognized RejectedVCH(mg/)DICHANDIPANCHC50 40 30 20 10 5 4 3 2 1 611.

10 Toxicity of Volatile corrosion Inhib-itorsRepresentative volatile corrosion inhibitor, DICHAN, issafe without toxicity and accumulation functions unlessit is drunk much in ordinary usage. However, somebitterness is felt in mouth and nasal mucosa arestimulated so that use of mask, etc. is recommendedwhen much DICHAN must be always handled. For yourinformation, summary of a bulletin at the Department ofPharmaceutical Chemistry in the University of Californiais shown in Table 5 and Table General Considerations on Apply-ing Volatile corrosion Inhibitor (VCI)(1) VCI amount of standard usage is referred to Table 7,and follow the instructions from the manufacture.(2) Evaporation gas travels at within about 30cm so thatit must be not kept away 30cm or more. Also in caseof rust prevention paper, use the internal side, whicha chemical is applied.(3) Evaporation gas is heavier than air so that VCI mustbe used at the possible top of the space that requiresrust prevention.