Technology Trends in Automotive Surface Coatings

1. Technology Trends in Automotive Surface Coatings Jong Myung Park Buhmwoo Institute of Tech November 15, 2006

2. CONTENTS Pretreatment System Electro-Coat Pre-sealed System Pre-primed System UV-Curing System Conclusion Introduction Basics of Organic Coating System

3. 내구성 자동차 강판 요구성능 적용 기술 • DP (Dual Phase) • TRIP (Transformation Induced Plasticity) 경량화 및 강도 , 연신율 우수 고속 충돌성 우수한 고강도 강판 • BH STEEL Bake hardening steel 약자로 , 차체 성형시 강도가 낮아 가공성 우수하고 , 성형 후에는 자동차 도장공정을 거치면서 받는 열에 의하여 강도가 증가되어 최종 자동차 완성된 이후 높은 강도 구현 가능 . 고내식성 표면처리 강판 • Presealed •Preprimed • Pre-finished • Pb,Cr-free 표면처리 강판 • 고강도강 사용으로 차체무게 감소 – 연비 감소로 인한 환경오염 배출물질 감소 Introduction The Technology of Properties for Automotives 환경친화성 경량화 안정성 가공성

4. Purpose of Coatings for Automotives Protect from 미관 상품성 향상 방 청 방 음 입체감 평활성 광택감 색 채 SUN LIGHT(UV, IR) Water, Oxygen Sand, Dust Gum, Soot Sea breeze Exhaust gas Improve Introduction

5. Coating Process of Car Body Introduction

6. Global Automotive Paint Driving Force Introduction Higher Quality 1.Appearance and Durability 2.Color and Corrosion resistance 1. Cut-down Production Process 2. Save Labor Usage Lower Cost 1. Lower Paint Usage 2. Reduce VOC 3. Reduce Waste Water Environmental Compliance 1. Direct Coating on Steel Sheet 2. Co-work Automotive & Steel Company Shorter Development Times

7. 코팅 시스템 개론 일반적 코팅 구성 성분 Resin Adhesion & Film formation Key Ingredient for performance Solvent Rheology control Solvation & Dilution Drying behavior Additive Defoaming Rheology control Surface wetting/levelling Pigment Surface protection Special function Decoration/Color Protection Functionality Decoration (Automotive, Heavy-duty, PCM, Industrial) UV protection

9. 코팅 시스템 개론 Resin Crosslinking 수지의 Reactive Functional Groups 과 Crosslinker 간의 화학적 반응에 의하여 생성되는 3 차원 Polymer Network * Crosslinking Technology 장점 - Low Mw Resin --- Easily Soluble - High Solids Level 가능 - 범용적인 다양한 수지 및 경화제 군 - Heat 조건에서 용해되지 않음 - 우수한 Solvent Resistance - Low Mw 로 인하여 Compatibility 양호 * Crosslink 위한 화학 반응 - Oxidation - Melamine Crosslink - Isocyanate Crosslink - Epoxy Crosslink Resin Functionality Crosslinkers Hydroxyl Group (-OH) Carboxyl Group (-COOH) Epoxies Unsaturated Fatty Acid Amino Resins / Poly-isocyanate Amino Resins / Epoxies Polyamines / Poly-carboxylic Acid Oxygen

10. 코팅 시스템 개론 코팅용 수지 구분 Thermosetting Resin Air-drying 2-K Reactive Baking Type Stand Oil/Bodied Oil Varnish (Oleoresinous Varnish) Ambient Dried Alkyd Resin Polyurethane Resin Epoxy Resin Alkyd Resin Polyester Resin Thermo-setting Acrylic Resin Melamine Resin Phenol Resin Blocked Isocyanate Urea Resin Thermoplastic Resin Cellulose (NC & CAB) Chlorinated Rubber Thermo-plastic Acrylic Resin Vinyl Resin

11. 구성 성분 Acrylic Monomer Initiator Organic Solvents Emulsifier Properties Versatile / Durable Good Color Gloss Retention Good Resistance - UV - Hydrolysis - Oxidation Characteristics Solvent Composition Molecular Weight Tg Solubility Uses Automotives Heavy Industries Industrials Architectures Special Applications Acrylic Resin 코팅 시스템 개론

12. Acrylic Resin Crosslinking Reaction 코팅 시스템 개론 O O H O O H O H O N C H 2 O R ( R O C H 2 ) 2 N O N R N O O O H H O C N R N C O O H E p o x y I s o c y a n a t e A m i n o - F o r m a l d e h y d e

13. Amino Resin 코팅 시스템 개론 Urea / Melamine Formaldehyde Alcoholic Solvent Brittleness High Speed Cure Self-condensation Mineral Spirits Tolerance Alkoxy Type & Degrees Solubility & Compatibility Stability Cure Rate Acrylic Polyol Polyester Polyol Alkyd Special Applications Raw Material Characteristics Properties Uses (for Crosslink)

14. Amino Resin 반응 메커니즘

15. Polyester Resin 코팅 시스템 개론 Acid Alcohol Solvents Flexibility Good Adhesion Good Chemical Resistance Solvent Composition Molecular Weight Industrials Pre-coated Metal Heavy Industries High Crosslinking Density Automotives Raw Material Properties Characteristics Uses Good Hardness

16. Polyester Resin 반응 메커니즘 코팅 시스템 개론 O H H 2 C H 2 C O H n + H O O C C O O H n e t h y l e n e g l y c o l t e r e p h t h a l i c a c i d O H 2 C H 2 C O C O C O O n + 2 n H 2 O p o l y e t h y l e n e t e r e p h t h a l a t e

17. Polyester Resin 반응 메커니즘 코팅 시스템 개론

18. Epoxy Resin 코팅 시스템 개론 Bis-phenol A Epichlorohydrine Solvents Good Reactivity Good Chemical Resistance No Side Products Solvent Composition Molecular Weight Industrials Heavy Industries Automotives UV Sensitivity Floor Coatings Electronics Raw Material Properties Characteristics Uses Good Mechanical Properties

19. Epoxy Resin 반응 메커니즘 코팅 시스템 개론

20. Urethane Resin 코팅 시스템 개론 Isocyanates Glycols Solvents Good Adhesion Good Mechanical Properties High Gloss Isocyanate Type Cure Rate Sealants Architectures Industrials Hardener for Acrylics Hardener for Polyesters Raw Material Properties Characteristics Uses Good Electro-isolation Easily Gellation Yellowing

21. Urethane Resin 반응 메커니즘 A) (Prepolymer) + H 2 O B) ( 중간체 Amine 구조 ) + CO 2 ↑ 상온 경화형 A + B 2 액 경화형 A) B) (Prepolymer) HO ----------------- OH (Polyol) A + B 코팅 시스템 개론 CH 3 NCO NH OCO -------OCC NH NCO CH 3 CH 3 NH 2 NH OCO --------OCC NH CH 3 NH 2 C O NH CH 3 CH 3 NH NH NH OCO------------ OCO------------ OCO OCO NH NH CH 3 NH C O CH 3 NH CH 3 NCO NH OCO -------------OCC NH NCO CH 3 ----- OCONH NH OCO ------- CH 3 n

22. Pigments 구분 및 역할 코팅 시스템 개론 도막형성 물질과 혼합되어 , 색상과 은폐 , 투명성 제공 및 기후와 부식에 대한 저항성 , 도막 강화 기능 등 부여 Pigments Titanium Dioxide Prime Pigment Extender Pigment High Refractive Index (Scatter Light) High Cost Organic & Inorganic (Oxides) Calcium Carbonate, Talc, Clays Barium Sulphate, Silicas * Reactive Pigments (Rust Protection – Passivation) - Borates - Chromates - Leads - Molybdates - Phosphates - Silicates * Barrier Pigments - Talc - Aluminum - Mica - Silver Paste Color Shade Transparency Hiding Power Organic pigment Property Inorganic pigment Polarity non polar polar Surface area large small Particle size small large

23. Pigment Dispersion 코팅 시스템 개론 Repulsion Attraction Dispersion Flocculation Primary Particle (Ideal Dispersion) Agglomerate Flocculate ( 고체 / 기체 ) Flocculated ( 고체 / 액체 ) Deflocculated ( 고체 / 액체 ) Wetting Dispersing Stabilization Coating System Stabilization Mechanism Solvent-Based Steric Hindrance / Charge Water-Reducible Charge / Steric Hindrance Emulsion Charge Stabilization

24. Solvents 역할 코팅 시스템 개론 수지 및 기타 원료의 용해 , 원활한 작업 위한 점도 조절 그리고 코팅 안정성 및 흐름성 조절 용도로 사용 Evaporation Rate Solvent Diffusion Solvent Activity Characteristics Viscosity Diffusion Ratio Density Water Solubility Electrical Resistance Total Cost in Use Right Solvency for the Application Evaporation Rate Issues HAPs, VOC Regulation Compliance Odor & Toxicity Solvents Active Solvents Latent Solvents Diluent Solvents Dissolve Resin True Solvent for NC Lower Viscosity High Cost Assist the Active Solvents Reduces Viscosity Poor or Non-solvent Alone Intermediate Cost Diluents the System Non-solvent Low Cost Ketones / Esters Glycol Ethers Glycol Ether Esters Alcohols Water Aromatic Hydrocarbons Aliphatic Hydrocarbons

25. Dissolve Film Formers Paint Removers Cleaning Metals Cleaning Fluids Coalescing Aids Uses Solvents 비교 코팅 시스템 개론 Solvent Type Aromatic HC Alcohol Ester Ketone P-series (Dow) E-series (Dow) Typical Solvent Xylene IPA or Butanol N-BuAc or n-BuPr MEK or MIBK PM or PMA EE or EEA Resin Solubility (Acrylics) Good Poor Good Excellent Fair Fair Resin Solubility (Epoxies) Good-Fair Poor Good Excellent Fair Good-Fair Evap. Rate Mid Fast Fast-Mid Fast Mid-Slow Mid-Slow Odor Poor Good-Fair Fair Poor Good-Fair Good-Fair Toxicity Poor Good Good Fair Excellent Poor Regulatory Compliance Poor Good Excellent Fair Excellent Poor

26. 코팅용 Solvents 코팅 시스템 개론 Solvent-based Water-based Wate r borne Water reducible High solids Conventional coatings Resin Active solvent Solvent (Dilutant) Resin Coupler Water Resin Active solvent Solvent Resin Water Coalescent Coatings Organic Loving Water Loving Alkyl P ortion Glycol H ead CH 3 CH 2 CH 2 CH 2 O CH 2 CHOH CH 3 CH 3 CH 3 O CH 2 CHOCH 2 CHOH CH 3 Alkyl P ortion Glycol H ead DOWANOL PnB DOWANOL DPM Solvent Partitioning

27. Additives for Coatings 코팅 시스템 개론 Additives Dispersants Wetting Agent Defoamer Control to Pigment Particle Sizes Pigment Stabilization (Electrostatic & Steric Stabilization) Thickener UV Stabilizer Control to Surface Tension (Silicone & Fluoro Chemistry) Control to Foam (Waterborne System) Control to Viscosity (ASE, HASE, HEUR, Bentone, Cellulose) Protection to UV Ray (Hydroxyphenyl triazine, Benzotriazole )

28. Wetting Agents 특성 코팅 시스템 개론 Wetting Agents Anionic Surfactant Cationic Surfactant Amphoteric Surfactant Hydrophobic Group with Hydrocarbon 12-18 Alkyl Group with –COOH, -SO 3 H, -OSO 3 H -COONa, -SO 3 Na -> Salt Shape Non-ionic Surfactant Hydrophilic Group with Cation -CH 2 N + CH 3 Cl - Surfactant with Anionic and Cationic both R 1 -(NH-CH 2 CH 2 ) 2 -NH + -CH2-COO - Non-ionic System Polyethylene Oxide Compound Ionic Type Non-ionic Type Lower molecular Higher molecular – – – – – – – – – With Additive Without Additive

29. Surface Tension 코팅 시스템 개론 Surface Tensions 80 70 60 50 40 30 20 Xylol Water White spirit Melamine resins Alkyd resins Acrylate Resins Phosphatized steel Untreated steel SMC-Polyester mN/m Solvents Resins Substrates aqueous Levelling additives

30. Defoaming 코팅 시스템 개론 Polydimethylsiloxanes No Defoamer with Defoamer Hydrophobic particles Foam lamella compatible incompatible 2 - 30 45 - 230 1800 - 2900 380 - 1500 Defoaming Flow Slip Hammertone x (CH 3 ) 3 Si O Si O Si (CH 3 ) 3 CH 3 CH 3 x

31. Thickener (Rheology) 코팅 시스템 개론 Viscosity Curve Thixotropy Viscosity Profile newtonian:  = const. pseudoplastic:  = f(D) (shear thinning) viscosity  shear rate D shear rate D viscosity   = f (time t) Flow cup 4 mm ICI cone/plate Brookfield storage leveling settling sagging transportation production stirring application Rotational viscometer 0,1 viscosity (Pa·s) 0.01 0.1 1 10 100 1000 10000 0.001 shear rate D (1/s)  100 10 1

32. UV Stabilizer 코팅 시스템 개론