PAINTING AND COATING PAINTING AND COATING OF PLASTICSOF PLASTICS

JAIME CYPHER JAIME CYPHER

RYAN SEYLERRYAN SEYLER

DANIEL WILSONDANIEL WILSON

IntroductionIntroduction

Purpose of coating and paintingPurpose of coating and painting• DecorativeDecorative

• For consumersFor consumers

• ProtectionProtection• From unwanted environmental effectsFrom unwanted environmental effects• Helps overall performanceHelps overall performance

Methods: Painting, Powder CoatingMethods: Painting, Powder Coating

Introduction Introduction

Background on PaintingBackground on Painting• More aesthetically pleasingMore aesthetically pleasing• Most common method of coating Most common method of coating • Paint applied to surface as liquidsPaint applied to surface as liquids• Higher surface energy = BetterHigher surface energy = Better

Introduction Introduction

Background on Powder CoatingBackground on Powder Coating• Used on metals, ceramics, & plasticUsed on metals, ceramics, & plastic• Powdered solid coating appliedPowdered solid coating applied

Preparation of PlasticPreparation of Plastic

Prevent foreign substancesPrevent foreign substances• Detergent cleaningDetergent cleaning

• Salts and OilsSalts and Oils

• GlovesGloves• Fingerprint soilsFingerprint soils

• Destaticizing air blow-offDestaticizing air blow-off• Operate in “clean room”Operate in “clean room”

Paint AdhesionPaint Adhesion

Overcoming surface smoothnessOvercoming surface smoothness• Micro-etch with chemical agentMicro-etch with chemical agent

• Avoid over and under etchingAvoid over and under etching• Solvent choice is criticalSolvent choice is critical

• De-glazing with abrasive mediaDe-glazing with abrasive media• Areas of frictional heatingAreas of frictional heating• Cross-linked skin formsCross-linked skin forms

Paint Adhesion Paint Adhesion

• Oxidative surface treatingOxidative surface treating• For non-polar plastic surfacesFor non-polar plastic surfaces• Polarity from chemical reactionPolarity from chemical reaction• Polypropylene and PolyethylenePolypropylene and Polyethylene• Open flame exposureOpen flame exposure• Photosensitizers and UV lightPhotosensitizers and UV light

PaintingPainting

Advantages of PaintingAdvantages of Painting• Protective coatingProtective coating• Richer color than internal colorantsRicher color than internal colorants• Thin coatings possibleThin coatings possible• Same color parts in assemblySame color parts in assembly

PaintingPainting

Disadvantages of PaintingDisadvantages of Painting• Poor adhesion to certain plasticsPoor adhesion to certain plastics• Air pollutionAir pollution

• Disposal of wasteDisposal of waste

• Paintability varies among plasticsPaintability varies among plastics

Types of Painting Types of Painting ProcessesProcesses

SpraySpray Silk-ScreeningSilk-Screening Dip-CoatingDip-Coating Rolling Rolling BrushingBrushing WipingWiping

SpraySpray

Most common and versatile methodMost common and versatile method Easily automatedEasily automated Air pressure & liquid stream mixedAir pressure & liquid stream mixed Distance from part & speed Distance from part & speed

importantimportant Overspray unimportant, booths usedOverspray unimportant, booths used

SpraySpray

AdvantagesAdvantages• Excellent surface Excellent surface

qualityquality• Uniform Uniform

thicknessthickness• Few runsFew runs• Few Few

imperfectionsimperfections

Silk-ScreeningSilk-Screening

Series of screensSeries of screens preparedprepared• Multi-color imagesMulti-color images

•One screen per colorOne screen per color• One screen per portionOne screen per portion

Drying time necessaryDrying time necessary

Silk-ScreeningSilk-Screening

AdvantagesAdvantages• Flat & cylindrical partsFlat & cylindrical parts• High volume productionHigh volume production

DisadvantagesDisadvantages• Adhesion problemsAdhesion problems

• Due to bad preparationDue to bad preparation• Presence of mold releasePresence of mold release

OthersOthers

Dip-CoatingDip-Coating• Immersion in paint & rotatingImmersion in paint & rotating

Brushing, Rolling, & WipingBrushing, Rolling, & Wiping• Used less frequentlyUsed less frequently• AdvantagesAdvantages

• Special effects Special effects • Small lotsSmall lots

Powder CoatingPowder Coating

ProcessProcess• Immersion in plastic particles or sprayedImmersion in plastic particles or sprayed• Baked at high temperaturesBaked at high temperatures• Caution of degradation from fusionCaution of degradation from fusion

Powder CoatingPowder Coating

TypesTypes• EpoxyEpoxy• HybridHybrid• Aromatic Aromatic

UrethaneUrethane• TGIC PolyesterTGIC Polyester

Powder CoatingPowder Coating

Advantages of Powder CoatingAdvantages of Powder Coating• Many types of finishesMany types of finishes• Better performanceBetter performance• Better for environmentBetter for environment• Low costLow cost

Powder CoatingPowder Coating

Disadvantages of Powder CoatingDisadvantages of Powder Coating• Degradation or softening possibleDegradation or softening possible

• Causes part deformationCauses part deformation

• Long color change timeLong color change time

New TechnologyNew Technology

In-Mold PaintingIn-Mold Painting• Automotive usesAutomotive uses

• Insert-molding techniqueInsert-molding technique

• Eliminates paint-facility expensesEliminates paint-facility expenses• Better design flexibilityBetter design flexibility• Recycling easierRecycling easier

New TechnologyNew Technology

2K Polyurethane Coating2K Polyurethane Coating• Automotive usesAutomotive uses• Excellent appearanceExcellent appearance• Excellent performanceExcellent performance

• Curing at low temperaturesCuring at low temperatures

• Wide variety of plasticsWide variety of plastics

MaterialsMaterials

Not to be consideredNot to be considered• PE, PP, and low polarity plasticsPE, PP, and low polarity plastics

• Low surface energyLow surface energy

Cautionary materialsCautionary materials• PC & PS PC & PS

• Exposure to sensitive solventsExposure to sensitive solvents

Design RequirementsDesign Requirements

Material SelectionMaterial Selection Adding raised part detailsAdding raised part details

• Ink applied using rollerInk applied using roller Flat surfaces if possibleFlat surfaces if possible

• Uniform thicknessUniform thickness• CheaperCheaper

ExamplesExamples

PaintingPainting

ExamplesExamples

Powder CoatingPowder Coating

ConclusionConclusion

Coating & Painting valuableCoating & Painting valuable• DecorativeDecorative• Protective Protective

Preparation is crucialPreparation is crucial Many different processes Many different processes Becoming more popular todayBecoming more popular today