Principles of Automotive OEM Coatings - FARBE UND · PDF filePrinciples of Automotive OEM...

Principles of Automotive OEM Coatings Dr. Ulrike KUTTLER

ALLNEX AUSTRIA GmbH - Our R&D Center in Graz

Allnex at a Glance

A 1.5 Billion $ private equity owned company with

a strong market position in 4 different business lines:

Liquid Resins and Additives (LRA)

Radiation Curable Resins (RAD)

Powder Resins (PCR)

Crosslinkers (XLR)

Different market segments:

Automotive

Industrial

Packaging coatings and inks

Protective

Industrial plastics

Specialty architectural

Sales 2012 by Product Line

Sales 2012 by Segment

2,000 people dedicated to Coating Resins

Allnex – Our global footprint

Allnex – Our Technologies for Automotive OEM Coatings

RESYDROL® : Waterdilutable Alkyd- and modified Alkyd resins Waterdilutable Polyester- and modified Polyester resins

DAOTAN ® : Waterdilutable Polyurethane dispersions

VIACRYL ® : Water- and solventdilutable Acrylic resins

MACRYNAL ® : Isocyanate crosslinkable Acrylic resins (s/b & w/b)

CYMEL ® : Melamine Aminoplast Crosslinkers (methylated, butylated as well as mixed alcohols range)

CYCAT ® : Catalysts for Melamine Amino Crosslinkers

ADDITOL ® : Additives for Pigment wetting Stabilizing aluminum pigments in waterborne Basecoats Leveling & flow Substrate wetting Degassing & defoaming

Metal & Pretreatment

Cathodic Electrodeposition „CED“ DFT: approx. 20µm

Primer Surfacer DFT: approx. 25 - 35µm

Automotive OEM Layers

Clearcoat DFT: approx. 50 - 60µm

Basecoat DFT: approx. 10 - 30µm

Topcoat DFT: approx. 50 - 60µm

Automotive OEM Layers - their main responsibilities

Cathodic Electrodeposition „CED“ Corrossion protection (together with pretreatment layer) of the car body Primer Surfacer – the „damping- and preparation“ layer Protection against mechanical impacts (stone chip protection ) Leveling of unevenness and irregularities (sanding marks, poor leveling / high roughness of CED) Basecoat – the „style / emotion“ layer Providing color and effect – also of high importance for supporting the shape of the car body Clearcoat – the „appearance and protection“ layer Appearance: Excellent leveling (smooth surface) High gloss and body Protection: UV radiation (causes degradation of the polymers) Chemicals (gasoline, acids, tree gum, bird droppings,……) Mechanical impacts (scratches, car wash brushes,…..)

Cathodic Electrodeposition

A short introduction

History

Basics

Coating composition

Tank

Adjustments

CED

Anodic Electrodeposition

Since 1961 (FORD-Patent)

Heyday: 1965 till approx. 1978

Cathodic Electrodeposition

Starting in 1975

State-of-the-art technology till today

CED - History

What do we need for CED? A conductive object to be coated

(all kinds of metal or metalized substrates)

Electric power (DC) generated by a rectifier

The CED bath with anode cells as counter electrodes

An oven (150 – 190°C) for the stoving process

CED - Basics

Advantages of CED

Fully automated

No limitation for the shapes of objects

Good penetration into holes (throwing power)

No overspray and other losses (except loss of the isocyanate blocking agent)

Best corrosion resistance of all coating systems

Disadvantages

Rather high investments for the coating line

Curing temperature >140°C

CED - Basics

Principle of CED

+

Elektrolyse Koagulation

+ -

Water/e-Coat

Electrolysis Coagulation

Anode: Formation of H+-ions (acid)

Cathode: Formation of OH--Ions (Base) The resin coagulates by the pH-shift

CED - Basics

1. Cationic resin dispersion (also containing the crosslinker)

2. Pigments

3. Cosolvents

4. Additives

5. Curing catalyst

6. Deionised Water

CED – The Coating Composition

1. Cationic Resin Dispersion for Primer:

Epoxy resin N N

OH OH H+

Organic acids like Formic, acetic, lactic,….

A. Backbone resin

RCOO-

B. Crosslinker: blocked aromatic Isocyanates

C. Catalyst: metal catalyst

polyacrylate N N

OH H+

OH

OH

Cationic Resin Dispersion for Monocoats:

B. Crosslinker: blocked aliphatic Isocyanates

RCOO-

A. Backbone resin

Performance Comparison

Epoxy - CED Acrylic - CED

Corrosion resistance + + + -

UV - resistance - - - + +

Feasible color range - - - + +

Stoving temperature > 160°C > 170°C

Salt Spray Test ASTM (500 hrs)

0

5

1 2 3 4 5

aromatic

aliphatic

acrylic/30% EP

acrylic/15% EP

Epoxy

Infiltration

[mm]

1

6,5

5

4

3

240 hrs Accelerated Weathering (QUV - B)

0

50

100

1 2 3 4 5

aromatic

aliphatic

acrylic/30% EP

acrylic/15% EP

epoxy

Loss of gloss

100

4

22

15

68

2. Colors/Pigments

Epoxy CED for car bodies: grey

TiO2, carbon black, (extenders)

Epoxy CED for small parts: black

Carbon black, extenders

Acrylic CED for Monocoat systems: different colors

Organic pigments

2. Colors/Pigments

For the pigment grinding a separate grinding resin is used!

The CED system consists of 2 components

the CED dispersion (clear, not pigmented)

the pigment paste

Both components are fed into the tank separately

3. Role of the Cosolvents:

Influencing film forming:

The higher the solvent content, the softer the film in the deposition stage:

the lower the film resistance

the higher the flow of electricity

the higher the film build

increase of the bath temperature has same effect

Well established cosolvents are Texanol, Hexylglycol, Phenoxypropanol and Butylglycol (as carrier for the others)

4. Additives

Anti crater agents (incompatible with the ecoat):

Edge protection additives

Zinc pinhole additives (use of cosolvents is also possible)

Dispersing additive: for preparing the water dilutable catalyst dispersion

5. Curing Catalysts

Blocked aromatic isocyanates need a metal catalyst for deblocking and crosslinking

Catalysts in use are DBTO, DOTO, Bismuth compounds

All catalysts need a special preparation to bring them into a water dilutable form, which cannot be hydrolised in the waterborne ecoat

E- Coat characteristics (CED)

Solids content 15 – 20 %

pH 4 - 6

Conductivity 800 – 1500 µSi

MEQ-value 25 - 40

(milliequivalent acid/

100 g solid resin)

Pigment binder ratio 0,15 : 1 (black)

< 0,1 : 1 (organic)

< 0,5 : 1 (grey)

General Parameters

1. Voltage 30 – 420 Volt DC

2. Current (Ampere) depending on film resistance

3. Deposition time (sec)

4. Bath temperature (°C)

5. Electric charge (As, Cb)

6. Deposition equivalent (Cb/g deposited ecoat)

Minimum Coalescing Temperature MCT

(Constant voltage)

10

15

20

25

30

35

40

20 22 24 26 28 30 32

µm

Bath temperature °C

Cosolvent addition: moves the MCT and µm to the right

irregular deposition regular deposition

CED - Process:

Deposition time 2 - 4 minutes

Loss of solid material is compensated by addition of new material (dispersion as well as pigment paste)

ANODE:

Formation of the neutralisation acid (removed by the anolyte)

Formation of oxygen

CATHODE:

Deposition, coating formation of hydrogen

Film Forming During the Electrodeposition

The amount of deposited material decreases with the time of deposition, as the film forms a layer with strongly reduced conductivity

Depending on the softness of the E- coat (Tg of the resin), normal film thickness (15 – 25 µm) up to high film build (25 – 50 µm) can be generated

Throwing power: the ability of the E- coat to penetrate into holes

The film is almost dry after deposition (<2% water) after rinsing

Circulation of Anolyte, Ultrafiltration:

ANOLYTE = liquid phase in the anode, which absorbs the acid which is generated by the deposition

ULTRAFILTRATION = additional removal of waterborne components from the coatings system.

Turnover

Is the time for full consumption of the material in the tank

Depends on coated surface/time

Typical turnover is 2-5 weeks, but can go up to 1 year (stability challenge!)

Tank size and turnover define the consumption of the material; tank size can go up to 500 m³ (bigger cars, buses)

Metal Substrates/Pretreatments

Blank steel (only used for testing purposes)

Iron phosphated steel (low end substrates)

Zinc phosphated steel (most common substrates for Automotive and GI, gives highest performance – depending on dotation and rinsing; Cr free rinse is a must in EU)

Sandblasted steel (very seldom)

Other metal substrates Mg, Al, …. deliver different deposition performance and have to be evaluated individually

Challenges:

Cratering (external contaminations)

Leveling

Pinholes (MCT – behaviour)

Coagulation in the tank (too low neutralisation, bacteria ?)

Redissolution (too low pH in CED)

New metal pretreatments (e.g. Zirconium- based)

Primer Surfacer

A Short Introduction

History

Basics

Coating composition

Trends

Primer Surfacer

Only solventbased (s/b) chemistry till late 1980 / early 1990s

Worldwide first waterborne (w/b) Primer Surfacer at Opel in Germany early 1990s

Other OEM‘s (VW- Group, Volvo, Daimler, BMW,…..) followed within the next decade

Today w/b Primer Surfacer is „state of the art“ but still a high amount of s/b technology in use (Fiat, Renault, PSA, OEM‘s in US and Asia,……)

36

Primer Surfacer - History

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

Europe Eastern&Central

E.

Americas Japan Asia

w/b Powder solvent

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%


E.

Americas Japan Asia

w/b Powder solvent

Technology Segmentation Primer Surfacer: Development from 2004 to 2010

Primer Surfacer

Europe 2004

East & Central Europe

2004

Americas 2004

Japan 2004

Asia 2004

(Outside JP)

WB 40% 10% 8% 10% 5% POWDER 2% 0% 51%

SB 58% 90% 41% 90% 95% 100% 100% 100% 100% 100%

Primer Surfacer

Europe 2010

East & Central Europe

2010

Americas 2010

Japan 2010

Asia 2010

(Outside JP)

WB 70% 14% 11% 30% 10% POWDER 4% 0% 70%

SB 26% 86% 19% 70% 90% 100% 100% 100% 100% 100%

Application of the Primer Surfacer with ESTA (electrostatic application) by means of high speed bells

Dry film thickness (DFT) can vary from 20 – 35µm

Standard baking conditions: 20min/165°C (at some OEMs lower temperatures down to 145°C )

Each OEM / OEM line has more or less different requirements

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Primer Surfacer - Basics

Main Requirements for the Primer Surfacer

Excellent Appearance (gloss, leveling, absolutely NO surface defects)

Broad application window = high robustness of the Primer Surfacer (temperature, humidity, application speed , baking conditions……) to achieve high first run o.k. rates

Excellent adhesion to different CED- and PVC qualities

Excellent intercoat adhesion to a broad variety of Basecoats

Excellent humidity resistance

Excellent mechanical properties – tough elastic even at -20°C

Shear & storage stability

…….

......

39

Basics

40

s/b Primer Surfacer w/b Primer Surfacer

Polyester (mod. Alkyd) mod. Alkyd Epoxy resin Polyester (PU- mod.) Melamine Crosslinker Melamine Crosslinker Benzoguanamine Crosslinker blocked Polyisocyanate Pigments Pigments Extenders Extenders Additives Additives Solvents (> 40%) Solvents (< 5%)

Primer Surfacer – The Coating Composition

41

Basic Resin

EPOXY Modifier Resin

PU Modifier Resin

Polyester Modifier Resin

Adhesion

Corrosion resistance

Pigment wetting

Levelling

Hardness

Economic efficiency

Stone chip resistance

IMPROVE

Primer Surfacer – The Coating Composition

Trends / Challenges for the Primer Surfacer Layer:

Further improved appearance (gloss, leveling)

further broadening of application window („robustness“)

Lower cost / higher productivity

Low bake (< 120°C?)

Elimination of Primer Surfacer layer in „Compact Paint processes“

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Basecoat


History

Basics

Coating composition

Trends

Basecoat

Only solventbased (s/b) chemistry till mid 1990s

All German OEM‘s meanwhile use w/b Basecoat

Today w/b Basecoat is „state of the art“ but still a high amount of s/b technology in use (Fiat, Renault, PSA, OEM‘s in US and Asia,……)

Due to steadily increasing legislative pressure in China w/b Basecoat technology is growing much quicker than expected.

45

Basecoat - History

0

10

20

30

40

50

60

70

80

90

1997 1999 2001 2003 2005 2007 2009 2011 2013 2015

World (w/b) World (all)

Mio

Ca

rs

w/b Basecoat in Global Car Production

% w

/b B

C

Conversion from s/b to w/b OEM Basecoat

Application of the Basecoat with ESTA (electrostatic application) by means of high speed bells or for metalic Basecoats ins 2 runs (ESTA / pneumatic gun)

Dry film thickness (DFT) can vary from 10 – 30µm (color dependant!)

Standard baking conditions: 10min/80°C, followed by 20min/145°C (together with Clearcoat)

Due to the huge variety of colors and effects the most sophisticated paint layer of the car. An advanced formulation know how as well as carefull resin selection is key!

48

Basecoat - Basics

Main Requirements for the Basecoat

Excellent appearance (effect, leveling, absolutely NO surface defects)

Excellent adhesion to different Primer Surfacer qualities

Excellent intercoat adhesion to a broad variety of Clearcoats



Shear & storage stability

Robust in application

…….

......

49

Basecoat - Basics

50

s/b Basecoat w/b Basecoat

Polyester (PUD mod.) PUD, Polyester, Acrylic CAB Thickener Melamine Crosslinker Melamine Crosslinker Pigments Pigments Talcum Talcum Additives Additives Solvents (> 70%) Solvents (~ 10%)

Basecoat – The Coating Composition

Polyurethane dispersion (PUD)

Is providing adhesion, flexibility, appearance (flip flop effect in metallic BC) and stone chip properties. Very important component in the formulation!

Acrylic dispersion

Is providing hardness, physical drying, helps to fix the aluminum pigment and is decreasing overall formulation cost

Melamine resin

Is improving leveling, wetting of Clearcoat, and intercoat adhesion (BC/CC), increase open time of BC

Polyester

Can help to improve levelling, adhesion, flexibility and stone chip properties. Is also used in pigment pastes.

Thickener

Is providing the rheological properties for the BC. Very important in metallic BC to achieve a perfect flip flop effect

Basecoats – The Modular Approach

52

Soft - Segments Hard - Segments

In the synthesis of PU dispersions Polyisocyanates (hard segments) and Polyols (soft segments) are co- reacted in a polyaddition reaction.

OH-Polyester

OH-Alkyd

OH-Polyether

OH- Acrylate

OH- Polycarbonate

Polyisocyanate (TDI, IPDI,

TMXDI...)

Diol

Dimethylolpropionic acid

(Amine)

Structure of PU-Dispersions

53

N N

NO O

O

(CH2)6 OCN

(CH2)6 OCN

(CH2)6O C N

(CH2)6O C N N N N

O O

H H

(CH2)6 OCN

(CH2)6 OCN

O C N

OCN

CH3

CH3

CH3

OCNO C N

(CH2)6O C N N N

O

O

(CH2)6 OCN

(CH2)6O C N OCN

Hexamethylene diisocyanate (HDI)

Isocyanurate

Biuret

Urethdion

Isophorone diisocyanate (IPDI) Dicyclohexylmethandiisocyanate (Desmodur W)

Aliphatic / Cycloaliphatic

Typical Hard - Segments

54

CH3

OCNO C N

OCN

OCN

OCNO C N

CH3

OCN

OCN Toluylene diisocyanate (TDI)

Diphenylmethane diisocyanate (MDI)

Aromatic

Typical Hard - Segments

55

Soft-Segments Hard-Segments

Co-reacting Soft- and Hard-Segments

Neutralization (amines or strong bases)

Dispersing in water

Chain elongation Chain stopping

Schematic Production Process for PUDs

„ACETONE“ PROCESS 1. Polyaddition (i.e. co- reaction of soft segments with Polyisocyanates and a

hydrophilic acid component) as well as the chain extension step (with Di- oder Polyamines) is run in Acetone (homogeneous phase)

(instead of Acetone solvents like e.g. MEK, MIBK, THF are also suitable)

2. After the neutralization- and dispersion step the Acetone is distilled off

Advantages:

• Very universal • Viscosity during synthesis easy to control

Disadvantages:

• complex and expensive • residual solvent in the resin • Process not sustainable • Unfavorable yield

Different Production Procedures for PUDs

„MELT“ PROCESS

1. Polyaddition (i.e. co- reaction of soft segments with Polyisocyanates and a hydrophilic acid component) is run WITHOUT any solvent (in a melt)

2. A potential chain extension step is run AFTER the neutralization and dispersion step (i.e. in water)

Advantages:

• NO residual solvent • Food yield • No „solvent waste“

Disadvantages:

• Tricky process (very high viscosities) • Process not suitable for all the different PUD- chemistries


„SOLVENT“ PROCESS

1. Polyaddition (i.e. co- reaction of soft segments with Polyisocyanates and a hydrophilic acid component) is run WITH solvent (NMP/NEP are the most common ones)


Advantages:

• very universal • viscosity during synthesis easy to control

Disadvantages:

• Resin may contain quite high amounts of solvent • Toxicology and price of NMP / NEP


„MONOMER“ PROCESS

1. Polyaddition (i.e. co- reaction of soft segments with Polyisocyanates and a hydrophilic acid component) is run in acrylic monomers (acrylic /methacrylic acid and esters thereof) that act as „solvent“


3. Radical polymerization of the acrylic monomers yields a solvent free, acrylic modified PUD (graft polymer)

Advantages:

• NO residual solvent • Good yield • No „solvent waste“

Disadvantages:

• Smart but tricky process • Only for acrylic modified PUDs (graft polymers)


60

Hard - Segment „ net-points“

Soft - Segment flexibility

Soft- and Hard- Segments within the polymer are leading to a „structure of domains“. This special stucture is creating the well known tough-elastic behaviour of PUD based coatings (even at low temperatures!)

Film Morphology

61

O

R NH C NH R N H C O R‘

O

R

Urea Urethane

Urea- as well as Urethane groups have a strong dipole moment. This is causing strong interactions with the surface of substrates excellent adhesion to “difficult substrates” like e.g. plastics Moreover this dipole moment is causing strong intermolecular forces (cohesion) outstanding mechanical properties and elasticity

PU Dispersions – Structure Properties

1. PUD‘s are produced by a polyaddition- reaction of soft segments (OH- group containing pre- polymers) with Polyisocyanates (hard segments) and a hydrophilic acid component

2. The different production procedures for PUD- resins are tricky and complex

3. The majority of the hard segments (Polyisocyanates) as well as many soft segments (OH- Polycarbonates, OH- Polyethers,….) are high price raw materials leading to PUD‘s with elevated price level

4. The achieved properties like • Adhesion to critical substrates • Outstanding mechanical properties • Excellent elasticity and abrasion resistance • Tough elastic behaviour even at low temperatures

make PUD‘s a first choice for Automotive OEM Basecoat applications!

PUD Basics – The „Take Aways“

Polyurethane Dispersions

Structure – Property Relationships

OH- Polyester OH- Alkyd OH- Polyether OH- Polyacrylate OH- Polycarbonate

Advantage

Very good appearance V. good mech. properties Good body Good substrate penetration Low viscosity Hydrolytic stability Quick drying Outdoor durability Hydrolytic stability Outdoor durability

Disadvantage

Hydrolytic stability Yellowing, outdoor durability Hydrolytic stability Poor light- and thermo stability Stability against oxidants High Price

Soft Segment

PUDs – Soft Segments

PUD‘s with low / medium molecular weight („chain stopped“ grades)

designed for crosslinking with Polyisocyanates or Amino resins

Advantages:

• Good leveling (due to slow physical drying) • Good degassing • Good pigment wetting • Excellent chemical- and solvent resistance properties • Excellent mechanical- and adhesion properties • Can be formulated with little to no solvents

Disadvantages:

• Need crosslinker (Polyisocyanate or Amino resin) • More complicated handling (valid only for 2K formulations) • Potlife (valid only for 2K formulations) • Price (expensive Polyisocyanate)

PUDs – The Molecular Weight

PUDs with high / very high molecular weight („chain extended“ grades) Designed for 1-pack applications (further crosslinking is possible)

Advantages:

• Quick physical drying • Excellent orientation of metalic pigments (bright metalic effect!) • Outstanding elasticity, adhesion and mechanical properties • No need for crosslinker • Easy handling (1 pack!) • No potlife

Disadvantages:

• Weak pigment wetting • Weak chemical- and solvent resistance properties • Poor leveling (due to quick physical drying) • Should be formulated with solvents

PUDs – The Molecular Weight

SUBSTRATE Plastic Metal

LAYER Primer Basecoat Monocoat Primer Surfacer Basecoat

MAIN BENEFIT Adhesion, mech. properties Adhesion, metalic effect, mech. properties Adhesion, stone chip properties Adhesion, metalic effect, mech. properties

PUDs – Preferred Fields of Application

Completely eliminate NMP/NEP from recipes (change in legislation)

„Lower cost“

Further improved robustness i.e. stable color position regardless of humidity / temperature conditions, spraying conditions, type of Clearcoat, substrate,…….

New color effects

Bell / bell application

Current Trends in the Base Coat Area

Clearcoat


Technology- and market overview

Basics

Coating composition

Trends

Clearcoat

Till 2010 the Clearcoat layer was the one with the broadest diversification. Following technologies were in use:

Technology In use at s/b 1K- Clearcoat Fiat, Peugeot, Renault,… (Melamine crosslinked)

s/b 1K- Clearcoat Toyota and other Japanese OEM‘s (Carboxy – Epoxy technology)

s/b 2K- Clearcoat VW, Audi, Mercedes, BMW,……. (Polyisocyanate crosslinked)

w/b 1K- Clearcoat Opel (Eisenach plant only), Mercedes (Melamine crosslinked) (Rastatt plant only)

Powder Clearcoat BMW (ONLY!!)

OEM Clearcoats – Technology Overview

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%


E.

Americas Japan Asia

w/b 1K s/b 2K s/b Carboxy-Epoxy Powder

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%


E.

Americas Japan Asia

w/b 1K s/b 2K s/b Carboxy-Epoxy Powder

CLEAR COAT

Europe 2004

Middle/East/Central EU2004

Americas 2004

Japan 2004

Asia 2004 (Outside JP)

WB 1.7%

1K Melamine

70.0% 80% 60% 21% 58%

2K 26.7% 20% 15% 30% 16%

1K_Acidcarboxy

25% 49% 26%

Powder 1.6%

100% 100% 100% 100% 100%

CLEAR COAT

Europe 2010

Middle/East/Central

Europe 2010

Americas 2010

Japan 2010

Asia 2010 (Outside JP)

WB 4%

1K Melamine

54% 80% 57% 21% 62%

2K 38% 20% 15% 30% 14%

1K_Acidcarboxy

27% 49% 24%

Powder 4.6% 0.5% 0.3%

100% 100% 100% 100% 100%

Technology Segmentation Clearcoat: Development from 2004 to 2010

Since 2010 a steady consolidation of Clearcoat technologies is ongoing: w/b 1K Clearcoat stopped at Opel Eisenach and Mercedes Rastatt ->

switch to s/b Clearcoat!

BMW stopped powder Clearcoat -> switch to s/b 2K Clearcoat

s/b 2K Clearcoat is increasing, but worldwide s/b 1K Clercoat still has a share of approx. 80%

OEM Clearcoats – Technology Overview

Application of the Clearcoat with ESTA (electrostatic application) by means of high speed bells

Dry film thickness (DFT) in the range from 50 – 60µm

Standard baking conditions: 20min/145°C

The paint layer where majority of final properties is provided by the resin technology. Carefull resin selection is key!

74

Clearcoats – Basics

Main Requirements for the Clearcoat

PREMIUM Appearance (gloss, leveling, absolutely NO surface defects)

Excellent adhesion to different Basecoat qualities

Excellent outdoor durability, no yellowing



Excellent chemical resistance (solvents, chemicals, acids, …….)

Excellent scratch resistance (carwash!!)

Robust in application

Easy to repair by sanding or polishing

......

75

Clearcoats – Basics

Basic components Properties

Acrylic resin Outdoor durability, chemical

resistance and hardness

Polyester resin Body, leveling, adhesion, scratch

resistance, outdoor durability

Sca mod. resins Antisagging and good flow/aspect

Melamine Crosslinker

Blocked Isocyanate Flexibility, chemical resistance

Catalyst Reactivity (if necessary)

s/b 1K Clearcoats

Basic components Properties

Acrylic resin Outdoor durability, chemical

resistance and hardness

Polyester resin Body, leveling, adhesion, scratch resistance, outdoor durability

Sca mod. resins Antisagging and good flow/aspect

Polyisocyanate Crosslinker

Melamine resin Additional crosslinking

s/b 2K Clearcoats

Technology

s/b 1K (Melamine)

s/b 2K (Polyisocyanate)

PROS

Price Robustness Scratch resistance Easy handling (no 2K equipment!)

CONS Formaldehyde release Acid- / chemical resistance Film build Appearance , gloss not for compact process 2K equipment needed Price Scratch resistance

No Formaldehyde issue Acid- / chemical resistance Film build Appearance Gloss Suitable for compact process

OEM Clearcoats – Technology Comparison

Appearance, appearance, appearance

„Lower cost“

Further improved robustness (less rework!)

Improved scratch resistance

Higher solids content (due to more stringent legislation)

Current Trends for the Clearcoat

Contact Details:

Dr. Ulrike KUTTLER

Global Application Technology Manager, Automotive

[email protected]

Phone: +43 50399 1302

mailto:[email protected]

Disclaimer: Allnex Group companies (“Allnex”) decline any liability with respect to the use made by anyone of the information contained herein. The information contained herein represents Allnex's best knowledge thereon without constituting any express or implied guarantee or warranty of any kind (including, but not limited to, regarding the accuracy, the completeness or relevance of the data set out herein). Nothing contained herein shall be construed as conferring any license or right under any patent or other intellectual property rights of Allnex or of any third party.

The information relating to the products is given for information purposes only. No guarantee or warranty is provided that the product and/or information is adapted for any specific use, performance or result and that product and/or information do not infringe any Allnex and/or third party intellectual property rights. The user should perform its own tests to determine the suitability for a particular purpose. The final choice of use of a product and/or information as well as the investigation of any possible violation of intellectual property rights of Allnex and/or third parties remains the sole responsibility of the user.

Notice: Trademarks indicated with the ®, ™ or * are registered, unregistered or pending trademarks of Allnex Belgium SA or its directly or indirectly affiliated Allnex Group companies.

© 2013 Allnex Belgium SA. All Rights Reserved

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