A Novel Approach to Corrosion Inhibitors for Coatings. - Halox

A Novel Approach to Corrosion Inhibitors for Coatings

Amanda Adams, Sr. Project Chemist Andy Balgeman, Project Chemist Shonda Prince, Project Assistant Theresa Kretz, Intern Student

Established in 1972 Recognized Leader in CorrosionInhibitor Technology Reputation for Superior TechnicalSupport Broadest Corrosion Inhibitor ProductLine in the Paints & Coatings Industry www.halox.com

‣What are sol-gels?‣Sol-Gel Metal Pretreatments‣Sol-Gel Paint Additives

Sol-gel or “silica-gel” Inorganic-organic hybrid Liquid corrosion inhibitor/Adhesion PromoterIllustration courtesy of Evonik Degussa GmbH

Inhibitive pigments or nano materials can be trappedunderneath the network formed, thus providing excellentcorrosion resistance of the pretreatment

Eco-friendly alternative

To find an aqueous Cr(VI)-free pretreatmentfor hot dipped galvanized and cold rolledsteel substrates which will achieve superiorcorrosion resistance

•Bare cold rolled steel panels were coated with a 10% solgelsolutions•Polarization resistance was measured and compared•Pretreatments compared•Bare metal•Bonderite952 and•Bonderite1000 P99X•Sol-gel pretreatment showed polarization resistancevalues similar to zinc and iron phosphated steels

Bare Cold Roll SteelBonderite 952Bonderite 1000 P99X10% Sol-Gel

Polarization resistance of cold rolled steel panels in aqueous 5.0% NaCl solution. (A)Bare cold roll steel (B) Bonderite ® 952 (C) 10% Sol-Gel treated cold rolled steel (D)Bonderite ® 1000 P99X

1-3 µm P/TGalvanized SteelControl @ 96 hrs SSTProprietary Sol Gel@ 96 hrs SSTProprietary Sol Gel@ 144 hrs SST

PUD PretreatmentCr-VI pretreatmentCCCHDGCr-free pretreatmentPUD + Sol-GelHDGPUD is anionicbased on polyestertype PURPost-add Sol GelRT dryDFT: 7.5 µmSource: HYDRAN ® 171 PUD is from DIC Corporation Sakai Plant, Japan14

PUD PretreatmentPUDPretreatment72 hrsSALT SPRAYHDG.3 milsBlank3% OrganicInhibitor A3% OrganicInhibitor B1.4%Sol Gel

Use of sol-gel in coatings

50 microns75 microns75 microns50 microns50 micronsSubstrate Substrate Substrate3-coats 2-coats 1-coat< 25 microns

Inhibitive pigments can be trapped underneath the networkformed, thus providing excellent corrosion resistance

HALOX SOL-GEL FEATURES• An additive for protective primers (S/B & W/B)• Etch primer• General primers• High gloss DTM finishes• Liquid adhesion promoter & corrosion inhibitor• Synergistic complement to Zinc Phosphate• Stand alone metal pretreatment alternative toCr 6+ compounds

Replace ZnCrO 4 in washprimers Replace Cr 6+ salts inepoxy alkyd or PUprimers Minimize white ruston GI and Al substrates Minimize black rust onGalvalume® (Al-Zn alloy)

Coating Type How OutcomeWaterborneWater reduciblealkyd direct-to-metal(DTM) enamelAdded in grindBoosted salt sprayBoosted blister resistanceWaterborneAcrylic lacquersealantAdded in baseReduced black corrosionSolventborneVinyl butyral washprimerAdded in thegrindReplacement for Cr-basedcorrosion inhibitorSolventborneMedium oil alkydprimerAdded in grindIncreased adhesion ongalvanized steel

336 hrs Salt Spray - Cold Roll Steel(DFT: 60 µm)Blank2% AmmoniumBenzoate2% CompetitiveOrganic Inhibitor2% Sol Gel

Water Reducible AlkydSalt Spray – 96 hrs – Cold Rolled Steel– 18 µmControl 3% HALOX 310 3% HALOX 310/0.5% Sol Gel

1200 hrs Salt Spray - Galvalume(DFT: 23 µm)Blank3%Competitor3% Sol Gel3% Sol Gel3% Anticorrosive

240 hrs Salt Spray – Hot Dip Galvanized(DFT: 58 µm)Blank6% CW-22301% Sol Gel6% CW-22301.5% Sol Gel

Thin Films◦ GI substrate◦ WB Acrylic lacquer◦ 336 hrs Salt Spray5 µm W/B clear coatGalvanized Iron(GI)SrCrO 43% Sol Gel3% ACP

Etch Primer (Replace toxic Cr 6+ in this layer)5-6 µm etch primerSubstrateAtmosphereTop CoatInhInhPrimerInhInhEtch PrimerSubstrate

Reduce Intercoatadhesionfailures with ,ALKYD, PU,EPOXY primersPrimersALKYD, PU, EPOXYCr(VI) vs. Cr-freeEtch PrimerSubstrate

ETCH PRIMER COMPLETE SYSTEMSubstrate25 µm5-6 µmSubstrateSubstrateAlkyd Primer1000 hrsSALT SPRAYGI substrateTopcoat Only7% Zinc Chromate1.5% Sol Gel5% ACP

ETCH PRIMER COMPLETE SYSTEMSubstrate25 µm5-6 µmSubstrateSubstrate2K PU Primer576 hrsSALT SPRAYCold Roll SteelTopcoat Only 7% Zinc Chromate 1.5% Sol Gel5% ACP

ETCH PRIMER COMPLETE SYSTEMSubstrate25 µm5-6 µmSubstrateSubstrate2K EpoxyPrimer1000 hrsSALT SPRAYAluminumTopcoat Only 7% Zinc Chromate 1.5% Sol Gel5% ACP

Acrylic DTM Post-AddsAcrylic DTM48 hrsSALT SPRAYCold RolledSteel1.5 milsBlank 1.4% HALOX 515 1.4% Sol Gel

Summary of Hybrid Sol-GelCorrosion InhibitorsEco-friendlyCr(VI) free metal pretreatmentReplace use of Cr(VI) pigmentsWaterborneEmbed anticorrosive pigmentsRoom temperature curableSuitable as additive for coatings