Werner J. BlankKing IndustriesNorwalk, CT 06852

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WHAT IS VOC (VOLATILE ORGANIC CONTENT)

USA“any organic compound that participates in atmospheric photochemical reactions except those designated by EPA as having negligible photochemical reactivity”

AUSTRALIAorganic compounds with a vapour pressure of more than 0.01 mm Hg at 21°C, and with a boiling point of less than 250°C.EUany organic compound having at 293.15K a vapour pressureof 0.01kPa or more, or having a corresponding volatilityunder the particular conditions of use

German Legislation Concerning the Environment

! 1970 basically 2 laws:Abfallbeseitigungsgesetz,Bundesimmisionschutzgesetz

! 1996 Alltogether approx. 2000 laws, edicts, regulations and recommendations by the authorities

WHY REDUCE VOC ?

ELIMINATION OF SOLVENT POLLUTIONREDUCTION IN OZONE FORMATIONSAFETY IN WORK PLACEHEALTH OF WORKERENERGY USE FOR CURE

How is VOC Regulated

Enduse Regional control Location, Amount of paint used Per Object (surface area)

0

1000

2000

3000

4000

5000

6000

7000

MM

LBS

1985 1997YEAR

SPECIAL

ARCHIT

OEM

RESIN CONSUMPTION1985 - 1997

3.5 %

4.6 %

SL2375

0

100

200

300

400

500

600

700

GAL

LON

S M

M

85 act 90 pred. 97 act 02 predYEAR

THINNERS

WATER BASED

SOLV BASED

SOLVENT CONSUMPTIONACTUAL & PREDICTED

SL2374

SOLVENT EMISSIONProduct life cycle

APPLICATIONTRANSFER

DRYINGFLASH OFF CURING

CLEANING

0 20 40 60

Air-atomize guns

Airless guns

Air-assisted airless guns

HVLP Guns

Electrostatic

Plural-Component Equipment

Liquefied CO2

Spray Equipment

SL1506

Survey Product Finishing Online Magazine March 1997

0 50 100 TRANSFER EFFICIENCY, %

Plural component Hand Spray

Airless sprayLiquid CO2 spray

HVLP gunsElectrostatic spray

Flow coatingDip coating

Curtain coatingRoller coatingElectrocoating

APPLICATION METHOD

SL2503

COATING TECHNOLOGIESHIGH SOLIDS - SOLVENT FREE

VISCOSITY/SOLIDS & POTLIFE/DRY TIMEWATERBORNE

COSOLVENT, APPLICATION CONDITIONSDRY-TIMEELECTROCOATING

PRODUCTION VOLUME, SUBSTRATECURE TEMPERATUREUV/EB COATING

COMPLEX OBJECTS, PIGMENTSPOWDER COATING

LOW FILM THICKNESS, CURE TEMPERATUREFLOW AND LEVELING

AdvantagesReduces VOC and HAP emissions Reduces inventory Reduces fire hazardsReduces number of spray applications to achievea given film thicknessHigher crosslink density improves abrasion and mar resistanceCompatible with conventional spray equipmentReduces safety and odor problemsReduced air makeup in ovens

HIGH SOLIDS - SOLVENT FREE COATINGS

HIGH SOLIDS - SOLVENT FREE COATINGS

DisadvantagesGenerally requires high cure temperatures Sensitive to inadequate cleaning of substrateIs difficult to control film thicknessTacky overspray; difficult to clean Might require paint heater in systemDifficult to control sagging Has narrow "time-temperature-cure" windowCannot use in dip or flow coatingIs difficult to repair Shorter pot-life than conventional coatings

Advantages

Reduces VOC and HAP emissions Can use conventional application processesReduces toxicity and odorIs easy to clean upReduces disposal of hazardous wasteCan recover and reuse some waterborne paintsNon-hazardous waste disposal might be possible

WATERBORNE COATINGS

WATERBORNE COATINGSDisadvantagesHas tendency to foam Clean surface requiredLonger drying times or increased oven temperaturesHas difficulty obtaining high gloss finishHas difficult cleanup once coating is curedHigher cost Conversion might be expensiveLower transfer efficiencies for electrostaticIncreases runs and sagsRequires good temperature/humidity controlHeated storage

ELECTROCOATING

Advantages

Utilizes over 90 percent of coating material Uniform coating on all surfaces High production ratesCorrosion-resistant coatingLow VOC and HAP emissions Can be fully automated

ELECTROCOATING

Disadvantages

Substrate limitation Separate lines for each colorHigh cost to installRequires sophisticated maintenanceDifficult coating bulky, small partsRequires de-ionized waterIs restricted to large volume finishingHas coating thickness limitationRequires corrosions-resistant equipment

RADIATION CURING UV/EB

Advantages

Lower VOC and HAP contentLower capital investment than conventional ovensShort cure timeLow energy costsConsistent performanceRequires small ovensLow air movement that reduces dust contaminationEasily installed/retrofittedReduces fire and explosion hazard

RADIATION CURING UV/EB

Disadvantages

Cure inhibition by pigmentsHigher RM costs for EB and UV coatingsPotential skin irritation problems with acrylate Shrinkage and adhesion problems with acrylateCuring sensitive to shape of part

POWDER COATINGAdvantagesNo solvent flash-off requiredNo coatings mix room neededMinimal oven length requiredLow ventilation requiredLess floor space requiredVOC and HAP compliant, i.e., no solventsGood corrosion resistanceHigh transfer efficiencies, 95-99%Saves energy Requires little operator expertise No hazardous overspray, waste sludgeReduces worker exposure to solvent vapors

POWDER COATINGDisadvantages

High cure temperature Small batches expensive to manufacture Metallic powder coatings not as attractive Appearance problems Enhances Faraday cage effect Difficult to achieve thin films below 1.0-1.5 milsMay cause powder clumping Difficult to change colors Needs cool, dry storage area Must pretreat substrate

COATING TECHNOLOGIES

HIGH SOLIDS - SOLVENT FREEVISCOSITY/SOLIDS, REACTION PRODUCTS

WATERBORNE COSOLVENT, REACTION PRODUCTS

ELECTROCOATINGCOSOLVENTS, REACTION PRODUCTS

UV/EB COATINGPOWDER COATING

High Solids Challenges

Nonvolatile - ViscosityCrosslinkingNetwork formationApplication characteristics

Potlife - reactivityRheology

SaggingPigmentation - Flocculation

Glass Transition Temperature

Structure

Molecular weight

Functional groups

Crosslinking

Viscosity

Physical properties

Chemical properties

Tg

Mobility of polymer chainsFree volume

1E-1

1E0

1E1

1E2

1E3

VISC

OSI

TY, P

OIS

E

0 50 100 150 200 TEMPERATURE, °C

VISCOSITY - TEMPERATUREOLIGOMERS MW 500

SL2502

Tg -50 to 60°C in 10°C

- 50°

60°

log η T = 13 - 17.44(T-Tg)

51.6+(T-Tg)

1E0

1E1

1E2

1E3

VISC

OSI

TY, P

OIS

E

0 50 100 150 200 TEMPERATURE, °C

500 1000 2000 4000 10000

VISCOSITY - TEMPERATUREOLIGOMERS, Tg 50°C

SL2500

T g o = T g in f -k

Mn

WATERBORNE COATINGS - COSOLVENTS

EMULSIONS-DISPERSIONS WATER-SOLUBLE

COALESCENCEOPEN TIMEFLOW - LEVELINGGLOSSADDITIVES

MANUFACTUREHANDLINGDILUTIONOPEN TIMEBLISTERING FLOW - LEVELING

Characteristic

Functional groupsAmount of functional groups*, MEQ/gSurfactantParticle size, micronMolecular weightFilm uniformityFilm formationCosolvent

WATERBORNE POLYMERS

Emulsion/dispersion polymerNon-random

0 to 2Yes0.1-2.0104-106

HeterogeneousTg dependentCoalescence

Characteristic

Functional groupsAmount of functional groups, MEQ/gSurfactantParticle size, micronMolecular weightFilm uniformityFilm formationCosolvent

WATERBORNE POLYMERS

Solution or bulk

Random distribution

0.5 to 2No0.01 to 0.1103-104

HomogenousNo Tg effectDispersion-synthesis

Chemistry

Non-ionic Polyether polyol Bisphenol A EO-PO diols Urethane diolsPolyester polyol Melamine resins Epoxy aliphaticUnsaturated compound

Resin COOH functional

Advantage - disadvantage

Water sensitivityExterior durabilityExterior durabilityCostHydrolytic stability Heat cure, formaldehydeNot stableLight stability, color

Amine

WATERBORNE REACTIVE DILUENT-COSOLVENTS

CROSSLINKING REACTIONWHY CROSSLINKING

RESISTANCE PROPERTIESCHEMICALSOLVENTCORROSION

MECHANICAL PROPERTIESHARDNESSFLEXIBILITY

INCREASE IN MOLECULAR WEIGHT-NETWORK

CROSSLINKING REACTION

Condensation reaction

R-H + X-L R-X + LH

ADVANTAGE

STABILITY-CURE RESPONSE

DISADVANTAGE

WEIGHT LOSSVOCFILM SHRINKAGESTRESSGLOSSCOST

CONDENSATION REACTIONS

Hydroxyl-carboxyl

Amino resins, melamine, urea formaldehydeFORMALDEHYDE, ALCOHOL, WATER

Blocked isocyanateKETOXIME, PYRAZOL, ALCOHOL

Silane, siloxaneALCOHOL

Hydroxyethyl amide -carboxylWATER

Methylol amide, glycoluril, cyclic ureaWATER

WATER

0

100

200

300

400

500

600

VOC

g/l

CALC. REACT. CALC. REACT.

VOC OF ACRYLIC/HMMM & DILUENTREACTION WEIGHT LOSS

ACRYLIC/HMMM80/20 ACRYLIC/DILUENT/HMMM

43/27/30

SL2389

0

50

100

150

VOC

g/l

CALC. REACTION

VOC OF POLYOL/HMMMREACTION WEIGHT LOSS

POLYOL/HMMM60/40

SL2390

POLYOL/HMMM60/40

Ring Opening and Addition Reaction

Epoxy, Glycidyl, Cycloaliphatic, OxetaneUretdioneCarbonateAzetidine2-OxazolineCarbodiimideAziridineAzlactoneCyclic urea acylIsocyanateMichael Addition

Approach

Molecular weightMolecular weightFunctional groupsFunctional groups typeCrosslinking typeCrosslinkingDispersion of resinWater addition

Details

<500Narrow MW distribution2-3 per polymer chainEnd groups, H-bond.Ring openingHydrogen bondingHigh Tg hetero. phase Breaking of H-bonds

REDUCTION OF VOC IN HIGH SOLIDS

1E0

1E1

1E2

1E3

1E4

TIM

E. m

inut

e

0.0001 0.001 0.01 0.1 DBTDL, Sn %

Potlife TACK FREE

PE/HDI-TRIMERCATALYST REACTION RATE

SL2245

COATING TECHNOLOGIES

HIGH SOLIDS - SOLVENT FREE

WATERBORNE

ELECTROCOATING

UV/EB COATINGPOWDER COATING

LOW MW, X-LINKING, H-BONDING

REACTIVE DILUENT, X-LINKING

REACTIVE DILUENT, X-LINKING

Pioneer in Waterborne CoatingsDr. Herbert Hönel

Vionova

Acknowledgement

King Industries Inc.Leonard J. CalboCarl G. Seefried

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