Nathan Kofira Technical Development Manager

Transcription

1 Nathan Kofira Technical Development Manager

2 Overview Types of Corrosion in Coatings Mechanisms of Corrosion Corrosion Inhibitor Selection 4 Formulating with Anti-Corrosives 5 Temporary Rust Prevention

3 1. CORROSION IN COATINGS

4 Examples of Corrosion Processes Of concern in coatings Flash Rust Galvanic Filiform Rapid, widespread corrosion seen during initial application. Contact between two alloys which promotes oxidation of the less noble metal. Differential aeration promotes this unique form of corrosion.

5 Short Term Corrosion Inhibition Flash rust is a rapidly forming corrosion event that typically manifests itself during application or shortly thereafter. The same driving force behind this can lead to in-can chime rust. R H 2 O H 2 O NH 2 R R H N H H N H NO 2 - H 2 O NO - NO e - Fe Fe Fe Fe Fe Fe Fe N Fe +2 H 2 O H 2 O Chemisorption Oxidation

6 Galvanic Corrosion Inhibition Uninhibited Weld Seams Sodium Nitrite Flash Rust Inhibited HALOX 515 Galvanic & Flash Rust Inhibition

7 Filiform Corrosion Inhibition 1.2mil Epoxy primer with 2mil Polyurethane topcoat on Aluminum. 500hrs. Filiform Corrosion Test Control Extender Pigments 9% Ion Exchange Inhibitor 2% HALOX 650 Filiform corrosion is efficiently controlled through the combined use of both an Ion Exchange Inhibitor and Organic Acid Inhibitor.

8 2. MECHANISMS OF CORROSION INHIBITION

9 Corrosion Inhibitors A material deposited as a film on a metal surface that either provides physical protection against corrosive attack or reduces the opencircuit potential difference between local anodes and cathodes and increases the polarization of the former... Any of a number of materials used to prevent the oxidation of metals

10 Mechanisms of Corrosion Inhibition Sacrificial Anodic Passivation Cathodic Passivation Ion Exchange Ambiodic (Mixed) Hydrophobicity Precipitation Vapor Phase

11 Corrosion Inhibitors must impact one of the two elements of the corrosion cycle. Anodic Reaction Slow the reaction rate of anodic dissolution. Produce reaction products which form a thin film over anode. Cathodic Reaction Disrupt the flow of electrons from the anode to the cathode. Produce reaction products which precipitate selectively at cathodic sites.

12 Non-Toxic Inorganic Inhibitors Commonly Used Inhibitors Zinc Phosphate Modified Zinc Phosphate Complex Phosphosilicate Modified Borates Complex Borosilicates Composition of Inhibitors [Zn 3 (PO 4 ) 2 2H 2 O] [M * Zn 3 (PO 4 ) 2 2H 2 O] [M * P 2 O 5 SiO 2 XH 2 O] [M * B 2 O 3 XH 2 O] [M * B 2 O 3 SiO 2 XH 2 O] M * may represent one of more of the following metals; Calcium, Barium, Strontium, Molybdenum, Aluminum.

13 Passivation Mechanism Zn 3 (PO 4 ) Hydrolysis + Fe 2+ - H 2 O Insoluble FePO 4 Precipitate M x (OH) x Substrate Fe Anode e - Cathode

14 3. CORROSION INHIBITOR SELECTION

15 Transition from Zinc Phosphate to Zn +2 Free Reduced Zn +2 Increased Barrier Properties Zn +2 Free Anodic Passivation Z-PLEX 111 HALOX 750 HALOX SW-111 HALOX CW-2230 HALOX CW-491 Passivation Zn +2 Free Passivation & Ion exchange HALOX 430 HALOX 430 JM

16 Barrier enhancement, lower Zn +2 5% Z-PLEX 111 5% Zinc Phosphate 1032 hrs. Salt Spray 1344 hrs. Prohesion WB Acrylic on CRS; 2mil; PVC 25%

17 Synergy of Hybrid Inhibitor 5% Zinc Phosphate 5% Modified ZnPhos 5% HALOX 750 Improved Wet Adhesion Reduced Blistering W/R Acrylic mod. Alkyd on Bonderite 1000; 400hrs. Salt Spray; 2.4mil

18 Organic Acid Anodic Inhibitors Key Benefits Improved Adhesion Key Features Wetting out of substrate Associative with additives and pigments Stabilization of soluble corrosion products Improved gloss retention Liquid products Reduced H 2 O permeability No Ionic crosslinking

19 Passivation with Organics By using HALOX 630 in place of Zinc Phosphate, the water sensitivity of the film greatly improved. 6mos. Marine Exposure 15% Zinc Phosphate 4% HALOX 630 2K Epoxy primer with PU topcoat on CRS; 2mil each

20 Organic Amine Cathodic Inhibitors Key Benefits Mechanism is independent of dissolved O 2 Key Features Barrier to electron diffusion at Cathode Associative with additives and pigments Stabilization of soluble corrosion products Potential replacement for Flash Rust inhibitors with added long term protection! Displacement of water High binding energy

21 Zero VOC Flash Rust Inhibition

22 Synergy with Inorganic Inhibitors Control 0% Organic 1% HALOX 515 5% HALOX 430 STY/Acrylic on CRS; 500hrs. Salt Spray; 2mil

23 4. FORMULATING WITH ANTI- CORROSIVE INHIBITORS

24 Formulating Advice Water Based Acrylics may exhibit some of the following symptoms when replacing the existing corrosion inhibitor system. VISCOSITY Δ Consider the Oil Adsorption when selecting the level and type of dispersant. SEEDING GELATION BLISTERING Utilize HALOX Organic CI s to lessen impact of Inorganic charge density. Examine the overall loading level of plasticizers and coalescents. Examine the water sensitivity and solubility of paint additives.

25 Dispersant Selection Control Disperse-Ayd W 22 TAMOL 165 A 5% HALOX SZP-391 1% HALOX 570 STY/Acrylic on CRS; 336hrs. Salt Spray; <100g/L VOC; 2.2mil

26 Formulating Advice Water Reducible and Modified Alkyds may exhibit some of the following symptoms when replacing the existing corrosion inhibitor system. VISCOSITY Δ Stability can be achieved by adding a coupling solvent or increasing the level of strong amine. SEEDING GELATION BLISTERING Pay attention to order of addition or increase the level of strong amine. Examine the overall loading level of plasticizer and coalescent. Balance the level of strong amine with weak amine or use amine containing HALOX Organic CI s.

27 Amine Selection At first glance, panel 4 appears to suffer from deficient corrosion protection, underlying cause is hydrolysis which can be corrected through amine modification. 3 4 Balancing Stability and Performance /25 50/50 25/ Weeks at 50 C W/R Epoxy Ester on CRS; 336hrs. Salt Spray; 1.5mil

28 Formulating Advice Solvent Borne and Hi-Solids Epoxies may exhibit some of the following symptoms when replacing the existing corrosion inhibitor system. POT LIFE Δ Minimize ionic crosslinking. APPEARANCE GELATION BLOOMING Balance the cure time and the polymer fluidity to achieve optimal film formation. Select a solvent which promotes low viscosity as crosslinking progresses. Monitor and adjust dwell time and temperature.

29 Obtaining Formulating Advice Fully developed formulations and technical assistance are available at Before arriving at this formula, we experimented with a number of options, searching for the right corrosion inhibitor. Impacts to pot life and corrosion performance were most critical in making the final decision.

30 Final SPF has less Zn +2 7% ZAM Plus 7% HALOX SZP-391 7% HALOX 750 Low Zn +2 /Organic Hybrid yields good pot life and corrosion protection. 2K High Solids Epoxy on CRS; 1000hrs. Salt Spray; 2mil

31 2K Waterborne Epoxy HALOX 430 JM HALOX HALOX CW-491 SZP-391 JM HALOX 550 WF Identifying the most critical aspects of your coating leads to one of the many offerings.

32 Key Features of HALOX 430 & 430 JM Ion Exchange and Passivation Heavy Metal Free Synergy with Organic Inhibitors in thin films

33 Corrosion Inhibitor Comparison Control 8% HALOX CW-491 8% WC-213 8% CAPP 8% AC-5 5% HALOX 430 2K Epoxy Dispersion on CRS; 1000hrs. Salt Spray; 3.5mil; PVC=34%

34 1K Waterborne Epoxy HALOX SW-111 HALOX 750 HALOX 550 WF Opportunities to explore SYNERGY with Organic inhibitors increase formulating latitude.

35 Key Features and Benefits of HALOX 750 Built In Synergy Inorganic/Organic Hybrid Multi-System Performance Use in Water and Solvent Borne Systems Excellent Passivation Outstanding Blister Resistance Enhanced Barrier Properties

36 Thin Film Applications HALOX 430 JM Synergy HALOX With SZP-391 JM Organics HALOX 550 WF Film thickness, adhesion, and gloss are typically the most critical parameters.

37 Jet Milled Inorganics 3% 6% Gloss 60.8 HALOX SZP Gloss 80.7 HALOX SZP-391 JM W/R Alkyd on CRS; 336hrs. Salt Spray; 1mil

38 Sol-Gel Technology in Coatings

39 Key Features of HALOX 550 WF Adhesion Promoter and Corrosion Inhibitor Additive for Protective Primers General purpose High Gloss DTM coatings Wash Primers Clearcoats Multi-Substrate Performance Galvalume - Improved Black Rust mitigation HDG - Improved White Rust mitigation

40 5. TEMPORARY RUST PREVENTION

41 Emulsifiable Rust Preventative HALOX 900 NOT a water displacing solvent blend! NOT an oily coating! NOT a resin or wax coating! Does NOT need to be removed before coating! Temporary protection for ferrous and non-ferrous metals.

42 Emulsifiable Rust Preventative No need to rinse before coating! Pretreatment yields better adhesion at the scribe and fewer blisters. HALOX 900 without 168 hrs. Salt Spray 672 hrs. QUV/Prohesion 2 cycles

43 Estimated Indoor Storage Interval HALOX 900 can be easily emulsified over a wide range. Dilute the concentrated product under agitation with water to achieve the desired level of rust prevention Water Dilution by Volume HALOX 900 concentrate Up to 1 week 1 week to 3 months 3 6 months 6 months to 1 year

44 Estimated Outdoor Storage Interval In dry, covered locations, HALOX 900 may provide rust prevention prior to coating Water Dilution by Volume HALOX 900 concentrate Up to 1 week 1 2 weeks 3 6 months <6 months

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