CO2 Spray Development Activities

ATS LO Maintainability TIMOklahoma City, Air Logistics Center

Rick Osterman7 October 1998

N

John Inks and Rick Osterman

26 May 1999

DOD Low VOC Coatings Application Workshop

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Equipment Development Activities

• Equipment Roadmap

• Benefit Comparisons

• Equipment Progress– Supercritical Carbon Dioxide

– Internal Funding (1998)– Air Force Funding (1999)

• Conclusions

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Equipment Roadmap

High VolumeLow Pressure

(HVLP)

Plural ComponentSpray(PCS)

Carbon Dioxide(CO2)

Convergent SprayTechnology

(CST)

1998

3Qtr

1999

4Qtr 1Qtr 2Qtr 3Qtr 4Qtr

Go/No-Go

EquipmentDown Select

Baseline Equipment Development Dem/Val ProcessSpec

Program Phases

Site 4 Dem/Val

& Process Specs

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• In Addition to Reformulating Coatings to Reduce or Eliminate Hazmats, NGC Is Evaluating Spray Equipment for Further Benefits

• Carbon Dioxide Spray (CO2)– Applicable to Primers, Topcoats and Specialty

Coatings– VOC and HAP Reduction

– Solvent Reduction– Cost, Cycle Time, and Film Quality Benefits

Equipment Environmental Benefits

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Carbon Dioxide SprayReasons for NGC Consideration

• Environmentally Friendly– Reduced VOC Emissions– Higher Transfer Efficiency– Higher Coating Rates– Minimal Solvent Disposal

• Improved Performance, Quality, Repeatability– Quicker Curing– Improved Film Smoothness

– Similar to a Class A Car Finish

• Cost Reduction– Reduced Process Flow & Labor – Less Over-Spray

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High Volume Low Pressure Diagram

A

Base

B

Catalyst

C

Thinner

1 QTPressure

Pot

1 QTPressure

Pot

Features and Benefits/Draw Backs• Manual Proportioning• Utilizes HVLP Spray Guns• Single Component (Batch) Design

• Work Life Limitation

ManualWeigh & Mix

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Supercritical CO2 Diagram

A

Base

B

Catalyst

C

Thinner

Features and Benefits/Draw Backs• Maximum VOC Reduction• Utilizes Airless Spray Gun• Single Component (Batch) Design

• Work Life Limitation

ManualWeigh &Mixing CO2

Pressure =1500 PSI

HEAT

HEAT

AdmixedCoating

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Unicarb CO2 Spray System Diagram

• Blend Supercritical CO2 with Standard Coating Solvents– Reduces Solvent

Content– Improves Coating

Finish

• Union Carbide Patented and Licensed Technology

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Unicarb CO2 Spray Spray Pattern

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ATS LO Maintainability TIM

• Advantages– VOC Reduction– Improved Flexibility– Improved Film Finish– Reduced Cure Times– Faster Coating Build

• Mandatory For– High VOC Materials– Low Flexibility Coatings

• ROM Costs– $160K to $320K – Can Operate 2 - 4 Spray

Guns From Each Unit

CO2 Spray Process Advantage, Mandate and Cost

CO2 Equipment Development Activities

N

• Internal Funding (1998)– Mil Spec Topcoat

• Air Force Funding (1999)– Program Baseline Primer and

Developmental Conductive and Topcoat– Developmental Primer and Topcoat– Developmental Topcoats– Developmental Waterborne Primer

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1998 CO2 Coating Evaluations

• Objective

– Evaluate Supercritical Fluid CO2 Coating Technology for Application of MIL-SPEC Qualified Paint Systems

• 1998 Project Goals– Reformulate a Mil-C-85285 Qualified Topcoat For Use in

UNICARB Coating Application System– Perform Testing & Evaluation of Coated Panels to

Selective MIL-C-85285 Requirements– Obtain Sponsorship by Northrop Grumman Programs to

Develop, Validate and Transition-to-Production the CO2 Paint Technology

– Identify DoD/Industry Partners for CRAD and CRADA Opportunities

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1) Complete Reformulation and Delivery of Paint System to Union Carbide

2) Application of Paint Using CO2 Spray System

3) Complete Coating Performance Testing

1998 Project Plan

Approach / Tasks

Milestones and Products

• Reformulate Hentzen Coatings’ MIL-C-85285, Gray Flat Topcoat for Use With Unicarb CO2 Paint System

• Spray Coating on Test Panels at Union Carbide

• Conduct Coating Performance Testing at NGC for Comparison to HVLP Spray Coatings

1st Qtr 2nd Qtr 3rd Qtr 4th Qtr

Problem / Need StatementEnvironmental Regulations Continue to Lower Allowable VOC Content. This Requirement Is Usually Achieved by Reducing Organic Solvent Content, But Low VOC Coatings Have Poor Surface Finish Quality. Supercritical Carbon Dioxide is Currently Used as a Solvent in Automotive Paint Formulations Producing a Class A Surface Finish.

Long Term Benefits• Reduce Paint Cure Times• Improve Finish Quality and Paint Application Rate• 50% VOC Reduction for Paints and Primers

ObjectiveReformulate a Mil-Spec Qualified Paint System to Use CO2 and Demonstrate Effectiveness 2

UNICARB

1 3

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• Northrop Grumman Corporation (NGC) Requested Hentzen Coatings, Inc. to Reformulate Their Mil-C-85285 Flat Gray Topcoat for Use in UNICARBSupercritical Carbon DioxidePaint System

• Hentzen, In Cooperation With NGC Produced the New Coating in Four Weeks

• Test Panels Were Sprayed at Union Carbide One Week Later

– Morphology Was Smooth and Continuous

– Unaided Visual Appearance of Coated Panels Was Excellent (No Orange Peel)

• Coating Performance Tests Completed

1998 Progress

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Test Results

• CO2 Coated Panels Met the Following Specification Requirements– Adhesion– Gloss– Surface Roughness– Heat Resistance– Solvent Rub– Hiding Power– Low Temperature Flex on Four Inch Mandrel

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Summary

• Exceeded Initial Coating Formulation/Application Goals

• Test Results Are Positive Warranting Further Evaluation

• NGC Procured Laboratory CO2 Spray Unit

• New Unit Will Be Tested to Certify Compliance South Coast Air Quality Management District Requirements– Minimum 65%Transfer Efficiency or Equivalence to HVLP

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1) Complete Phase I Coating & Spray Development

2) Complete Phase II Coating & Spray Development

2) Complete Equipment Demonstration & Validation

1999 Project Plan

Approach / Tasks

Milestones and Products

• Obtain Paint Samples from Various Suppliers

• Spray Paint Samples at Union Carbide

• Conduct Coating Performance Evaluation at NGC for Comparison to HVLP Spray Applied Coatings

1st Qtr 2nd Qtr 3rd Qtr 4th Qtr

Problem / Need StatementEnvironmental Regulations Continue to Lower Allowable VOC Content

Current Coating Processes are Time & Labor Intensive

Long Term Benefits• Reduce Coating Process Time• Improve Finish Quality and Paint Application Rate• Significant VOC & Emission Reduction

Objective

Evaluate Candidate Paint Systems to Use CO2 and Demonstrate Effectiveness 21 3

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Primer, Conductive, and Topcoat CO2 Baseline Coating Evaluation (24 - 25 August ‘98) at UCC

• Sprayed 3 Coatings– Courtauld’s Polyurethane Primer– In-House Formulation Conductive Coating– In-House Formulation Topcoat

• Added Small Amounts of Solvents to Coatings– MAK and EEP

• Film Spray Properties Were Acceptable

• VOC’S Were Reduced Over Baseline Coatings

• Coating Cure Rates Were Reduced – Primer Dry Hard Time Decreased From 3 Hrs to 2 Hrs

• Test Panels Were Sprayed for Physical Property Testing

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High Solids Primer and Topcoat CO2 Coating Evaluation (19 - 23 April ‘99) at UCC

• Sprayed 2 Coatings– US Paint’s High Solids Primer– US Paint’s High Solids Topcoat

• Added Small Amounts of Solvents to Coatings– MAK and EEP

• Film Spray Properties Were Acceptable

• VOC’S Were Reduced Over Baseline Coatings

• Coating Cure Rates Were Reduced – Primer Dry-to-Touch Decreased 50%

• Test Panels Were Sprayed

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More TopcoatsCO2 Coating Evaluation (20 - 22 May ‘99) at UCC

• Sprayed 2 Coatings– Hentzen’s Moisture Curing Topcoat– Dexter’s Polyurethane Topcoat

• Hentzen Topcoat Results – Added Small Amounts of MAK Solvent to Coating– Film Spray Properties Were Acceptable– VOC Was Reduced – Coating Cure Rate Reduced 50%

• Dexter Topcoat Panels Results– Required Mixture of Solvents to Meet Film Spray Stds.

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Waterborne PrimerCO2 Coating Evaluation (25 May ‘99) at UCC

• Sprayed 1 Coating– Spraylat’s Waterborne Primer

• No Solvents Were Added to Coatings– Sprayed As Supplied

• Film Spray Properties Were Acceptable

• Spray Panels Were Coated for Evaluation– Added Salt Spray Test Panels

– CO2 Interaction Could Change Coating pH Which Could Affect Corrosion Inhibitors

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Conclusions• Coating Reformulation is Not The Only Means of Meeting VOC

Reduction Requirements

• CO2 Cure Rate Acceleration Factor Dependent Upon Coating Being Evaluated

• Not All Commercial Coatings Are Applicable to CO2 Spray

• Keys to Reformulating for CO2– Formulation Stability– Solvent Selection

– Film Build– Compatibility

– Equipment Design– Single Batch Mix Versus Continuos Plural Mixing– Cold Versus Hot Circulating

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Conclusions Continued

• CO2 Spray Has Added Benefits Over Reformulation– Cost Reduction

– Reduced Touch Labor and Less Material– Cycle Time Reduction– Spray Process Finish Quality Improvements

• Must Evaluate Each Use of CO2 Against Need and Benefits – Subsequent Sessions Will Include Cost Analyses

• Equipment Development is More Capital Intensive Than Reformulation for HVLP Spray

• Additional Costs Should Be Offset Recurring Savings