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Workshop on Hazardous Substances Affecting Metallic-Coated Steel and Other Metals. May 23, 2007. Henkel – RoHS Compliant Passivate Discussion . Agenda: Position on RoHS Products Discussion Offerings Corrosion performance Field experience References. Henkel Position on RoHS.
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Workshop on Hazardous Substances Affecting Metallic-Coated Steel and Other Metals May 23, 2007
Henkel – RoHS CompliantPassivate Discussion • Agenda: • Position on RoHS • Products Discussion • Offerings • Corrosion performance • Field experience • References
Henkel Position on RoHS • Electrical and electronic equipment (not all end users) • Appliances • Computers • Televisions, video recorders • Hexavalent Chromium (CrVI) is critical element for metal passivation treatments listed in RoHS regulation • Must contain less than (0.1%) 1000 ppm. Hexavalent chromium or contain no intentionally added hexavalent chromium in any homogeneous layer • Henkel position is that passivate coatings do not become a homogeneous layer with substrate, but, the discontinuous layer of the passivate. (IBM agrees with this position). • Chromium free products are compliant simply because there is no chrome present • Chromium III (trivalent) products are compliant in both the product and as-dried surface since Cr(VI) is below 1000 ppm and no Cr(VI) is intentionally added. • Conversion of Cr(III) → Cr(VI) will not happen under “normal” circumstances • PH≥14 or extreme oxidation are required • Practical basis, Cr(VI) not present during life-cycle of the coated materials.
Hexavalent Chrome-Free Passivation Offerings • Three approaches: • Non-chrome containing inorganic passivate • Trivalent chrome inorganic passivate • Thin organic coating non-chrome containing (acrylic coatings)
Hexavalent Chromium Containing Inorganic Passivates: “Chemtreats” • Typical coating weight: 1.0 – 2.0 mg/sq.ft. Cr • Applied by flood squeegee and dried by hot air dryer • Corrosion performance by neutral salt spray (NSS): 96+ Hrs. • “Wet” corrosion tests: 800+ Hrs. • Low cost, good corrosion prevention • “Non-Paintable”
Henkel Passerite 5004 WChromium-Free Inorganic Passivate Major Coating Constituents • Molybdenum • Titanium • Phosphate • Fluoride • Organic Polymer
P-5004 W Chrome-Free Inorganic Passivate • Application • Bath Concentration 20%-100% (Dependent On Coater) 30% is Typical • Run as Flood or Dip/Squeegee or Chemcoater • Bath pH: 2.5-3.5 • Coating Wts.: 30-80 mg./sq.ft. (50 mg. is recommended) • Bath Temperature: <40C (104°F) • Strip PMT: 50-60C min., 120C max. (Above 120°F) • Drying Time: < 10 seconds recommended
Passerite 6001 / Passerite 6003 / Bonderite 6020Trivalent Chromium Passivate Application Parameters
Recommendations for Designing a System for Hex-Chrome Free Passivates • Solution contact time (time between application / drying ) – as short as possible. Less than 5 seconds excellent. • Chemcoater best method (spray / squeegee is acceptable) • Drying peak metal temp (PMT) - 120°F minimum (220°F max) • Equipment materials (contacts solution) – 316 or 304 stainless steel, or polymer (PVC, PEHD or PP) – no carbon steel • Wringer rolls – Hypalon, Viton or polyurethane covering – 45 – 55 shore hardness • Solution volume – as small as possible – less than 30 gallons – (Henkel “Coiltech” system) • Maintain pH below 2.5 – minimize zinc contamination • X-Ray fluorescence (Portaspec) recommended for coating weights
Henkel Standard Accelerated Corrosion Tests for Passivation Treatments • Neutral Salt Spray (NSS) • Wet Stack • Cleveland Condensing (CCH) • Butler Water Immersion (BWI)
Trivalent Based Passivation – Product Evolution Commentary “Passerite 6001 → Passerite 6003 → Bonderite 6020” • Continuous improvement in all of the following: • Corrosion performance (NSS) • Lower coating weight (lower applied costs) • Improved “paintability” • Improved conductivity (IBM and HP) • Less corrosive to equipment (304 and 316SS) • Bonderite 6020 – removal of organics – no foaming • Products have become more operator and end-user friendly • Next generation product – Bonderite 6010 – “fluoride free” – being tested in Europe
Thin Organic Non-Chrome Coating:(Replacement For Hexavalent Cr Containing Acrylics)Granocoat 342 • Primarily Used For Galvalume and HDG Coated Steel • Expected Performance: Roll forms without oil Good fingerprint resistance Excellent corrosion performance 180° – 220° F PMT
Non-Chrome Thin Organic Coating: Granocoat 342 Specifications:
Non-Cr Thin Organic Passivate: Application Parameters: • Coating Weight: 75-200 mg./sq.ft. • PMT: 170° - 250° F • Application Method: Chemcoater • Concentration: Used Neat • Application Temperature: Ambient • Recoil Temperature: <160°F
Granocoat 342 (Non-Chrome Acrylic) Summary: • Corrosion performance slightly inferior in NSS (HDG) and wet stack (Galvalume) • Roll-forming excellent and verified at 9-stage roll former (correlates well with Butler Building roll former) • “Paintable” surface • In use at Precoat – Portage and CFM for small applications • Successful trials at Mittal – Sparrows Point (Galvalume) and Nucor – Berkeley (HDG)
INORGANIC PASSIVATION HEX-CHROME FREEREFERENCES LIST CUSTOMERS