Multifunctional Protective Coatings for Weapon Systems

Chemical Agent Resistant Coatings

Lead Research and Development Activity

for Chemical Agent Resistant Coatings

Pauline Smith & John A. EscarsegaPauline Smith & John A. EscarsegaUS Army Research LaboratoryUS Army Research LaboratoryCoatings and Corrosion TeamCoatings and Corrosion Team

20th March 200620th March 2006JSEMJSEM

•Formulation

•Overview

•MIL-DTL-64159•MIL-DTL-53039

Doctrine

•AR 750-1 Mandates use of CARC on all Tactical Equipment

•Three Primary Principles

Survivability

EnvironmentalDurability

Formulation Objectives

• Reduce VOCs and Eliminate HAPs– Final goal near zero VOCs and HAPs– Minimize hydrocarbon based exempt solvents

• Enhance current durability– UV stable (4 year minimum with polymer flattened

formulas)• Sustain Survivability

– Resistant to Decontamination solutions (DS2 & STB*)

– Resistant to chemical warfare agents (nerve and blistering)

– Minimal detection in the visible and near IR range

Component vs. Formulated Coating

Resin

Pigment(s)

Extenders

Additives

Chemistry, degree of cure,Uniformity, cured resin structure,Impurities, UV absorption

UV absorption, surface chemistry,Particle size, crystal form, etc.

UV absorption, surface chemistry, size, type, distribution

UV inhibitors, antioxidants, surfactants, adhesion promoters

Individual Coating Components TAILOREDCOATING

•Pigment-resin interactions •Primer-topcoat interactions•Application•Defects and morphology•Synergy exists! Non-linearrelationships between components exist!

Important Factors

SolventsFilm carrier, flow properties, initial intercoat adhesion and compatibility and cure times

Resin Systems

• Polyureas: High performance, one component, Hydrocarbon solvent systems

• Water dispersible: High performance, Exceptional weathering, Two Component systems Combination of polyurethanes and polyureas

PIGMENTATION for CARC

–Control surface roughness to minimize reflectivity in the visual and IR regions

– Inert inorganics used for prime pigments

–Mimics chlorophyll reflectance curve for 383 Green

–Use of polymeric flattening agents

SILICEOUS VS. POLYMERIC

Polymeric beads

Diatomaceous silica Talc

MIL-DTL-64159 Type II Topcoat Cross-Section:Water Reducible CARC with Polymeric Extenders

•Integrated within Film

Arizona Exposure Data: Color Change

0.5 0.6

3.3

4.8

9.2

0.7 0.9

1.3 1.3 1.3

0.2 0.2

0.5

1.6

3.8

0.2

0.6

0.9

0.5

1.7

0

1

2

3

4

5

6

7

8

9

10

7 Weeks, 65.29 MJ/m2 13 Weeks, 120.08MJ/m2

25 Weeks, 203.4 MJ/m2 49 Weeks, 305.37MJ/m2

97 Weeks, 603.52MJ/m2

Exposure Time, Radiant UV EnergyNote: 280 MJ/m2 is equal to about 1 year of exposure

Col

or U

nits

MIL-C-46168, ARMY CONTROL SYSTEM

MIL-DTL-64159 TYPE II, ZERO HAPs

MIL-PRF-85285, NAVY CONTROL SYSTEM

MIL-PRF-85285 TYPE III (ZERO VOC TOP COAT)

Above 2.5 Failure

Florida Exposure Data: Color Change

0.2

0.5

2.6

4.9

7.4

0.9

1.1 1.2 1.3

1.6

0.4 0.3

0.5

0.9

2.6

0.9

1.3 1.4

3.3

2.9

0

1

2

3

4

5

6

7

8

7 Weeks, 75.03 MJ/m2 13 Weeks, 91.15 MJ/m2 25 Weeks, 151.41 MJ/m2 49 Weeks, 270.65 MJ/m2 97 Weeks, 501.37 MJ/m2Exposure T ime, Radiant UV Energy

Note: 280 MJ/m2 is equal to about 1 year of exposure

Col

or U

nits

MIL-C-46168, ARMY CONTROL SYSTEM

MIL-DTL-64159 TYPE II, ZERO HAPs

MIL-PRF-85285, NAVY CONTROL SYSTEM

MIL-PRF-85285 TYPE III (ZERO VOC TOP COAT)

Above 2.5 Failure

Water Reducible Coating

• Reduction with water

• No Hazardous Air Pollutants

• 1.5 – 1.8 lbs/gal of VOCs

• Enhanced mar, weather resistance

• Superior Flexibility

Water Dispersible CoatingStatus

• Multiple vendor participation

• Military Specification for Type I & II• MIL-DTL-64159

• Type I Silica Based Flattening Agents• Will eliminate at next revision*

• Type II Polymeric Based Flattening Agents

• Material Available and Aerosol kits approved (Coordination with GSA)

MIL-DTL-53039

• No Hazardous Air Pollutants ( All Type II formulas)

• 1.0 to 3.5 lbs/gal VOCs• Type I- 3.5 or less VOCs

• Will eliminate with next revision*• Type II -1.5 or less VOCs

• Formulation with polymer flattening agent being used to enhance mar resistance and weathering properties

MIL-DTL-53039Status

• Multiple vendor participation

• Military Specification for Type I & II• Type I 3.5 VOC ( some formulas HAP

free)• Type II 1.5 or less VOC & HAP free

• Changes in Mil Spec requiring testing and validation

• Super Tropical Bleach (STB) Completed*• Accelerated indoor and outdoor exposure• Live agent testing ( HD and GD)

MIL-DTL-53039TIMELINE for QPL

• Imperative to test all material to ensure coatings meet specification

• STB evaluation completed

• Mid May 2006 for Type I

• End of June 2006 for Type II

• Provide updates as testing is completed

Current Efforts

• Evaluation and Approval for MILSPRAY Touch up kits

• Cartridge Spray systems ( Spectrum Coatings for primary colors)

• Alternative Non-Hexavalent Chromium wash primer (on going)

• Partner with GSA to identify any non-CARC materials and certify all aerosol kits for CARC systems