Radiation-Curable Components and Their Use in Hard, Scratch-Resistant Coating Applications

Presentation Topics of Discussion

!   Current and potential hard coat applications.

!   Description of products tested and their attributes.

!   Taber haze and Taber abrasion resistance ●  Surface scratch resistance ●  Abrasion resistance (bulk properties)

!   Weathering resistance as a function product type and film thickness.

!   Barrier properties (substrate protection) of a typical hard coat formulation. ●  Influence that the addition of HALS and absorbers have on

weathering resistance and barrier property performance. !   Polyurethane Dispersion Products (PUDs) ●  Overall performance properties ●  Abrasion resistance study

2

Typical Abrasion Resistant Applications

!  Automotive & Architectural Window Film

!  Interior and Exterior Automotive Parts

!  Sporting Goods Including Skis, Snow Boards, Surf Boards & Golf Balls

!  Helmets Visors and Goggles

!  Ophthalmic Lens

!  Cell Phones

!  CD & DVDs

3

Highly Functional Urethane Acrylate Oligomers for Hard Coats

Attributes & Test Results

4

Weathering Resistant Urethane Acrylate Structure

OHNO

HN

OO

HN O

O

HNO

O

PolyolR

OR

O

Di-isocyanate Di-isocyanate Acrylating GroupAcrylating Group

l  Aliphatic Di-isocyanate

l  Polyester Polyol

5

Hard Coat Oligomers, Attributes & Hardness Test Results

Oligomer Acrylate Groups

Attribute Tg C by

DMA

Pencil Hardnes

s

Konig Pendulum Hardness

0000 Steel Wool Resistance, 50 Cycles, 1.0 Kg

Weight

CN9006 6 Fast curing with proven weathering performance.

77.25 8H 116 Pass

CN9026 6 More flexible with improved resiliency.

74.41 7H 98 Pass

CN9025 6 Higher Mw with lower toxicity.

80.0 7H 103 Pass

CN9013 9 Very fast curing with enhanced stain resistance.

135.0 7H 128 Fail

CN120 2 Lower cost with good chemical resistance

138.0 9H 138 Fail

6

Taber Testing of Urethane Acrylate Oligomers

!  Tabered Haze Testing

!  Surface Scratch Resistance

!  CS-10F wheel under 500g load for 10 cycles

!  Taber Abrasion Testing

!  Wear Through Resistance Properties

!  CS-17 Abrasion Wheel

!  Weight loss every 500 cycles to 2,000 cycles

!  1,000g load on each Taber wheel

7

Tabered Haze Testing

Application & Cure Conditions

!  Neat Oligomer Tested ●  Cut in 50% Acetone

!  Film Thickness: 3-6 microns (after flash off)

●  #5 wire bar used ●  Acetone flashed off prior to cure

!  50 fpm under (2) 300 w/in “H” lamps

!  CS-10F wheel under 500g load for 10 cycles

Delta Haze Results

1.5

2.8 3.1 3.2

8.9

0

2

4

6

8

10

12

CN9006 CN9026 CN9025 CN9013 CN120

InitialTaberedDelta  Haze

8

Taber Abrasion Testing

0

25

40

55

70

85

0

2128

3645

60

0

2333

4455

70

0

30

50

75

92101

0

40

70

96

120

140

0

20

40

60

80

100

120

140

160

0 100  Cycles 200  Cycles 300  Cycles 400  Cycles 500  Cycles

 Weight  Loss

CN9006CN9026CN9025CN9013CN120

CS17, 500g Load Mg of Weight Loss per 100 Cycles

(Base Formulation Tested: 75% Oligomer, 20% Monofunctional Diluent, 5% Alpha Hydroxy Ketone)

9

Scratch & Abrasion Resistance Conclusions/Observations

!   Aliphatic urethanes with high acrylate functionality result in cured films having excellent abrasion resistant properties.

!   High functionality results relate to a high crosslink density. This may result in micro-cracking of the cured film when coating thickness exceeds 5 microns.

!   This can be controlled by modification of the backbone structure to impart better flexibility or addition of lower functionality acrylates to the formulation.

!   These modifications and additions can improve the ductile properties of the film, making it malleable.

!   This results in cured film with abrasion resistant qualities, while improving the overall scratch resistance.

10

Weathering Resistance as it Relates to Oligomer Structure & Cured Film Thickness

Test Methods & Results

11

QUV Equipment & Conditions

!   8 hours of UV radiation @ 60 C

!   Followed by 4 hours dark condensation @ 40 C

!   The lamps were replaced every 400 hours to ensure constant UV intensity.

!   The bulb used was a UVA 340 from Q-Panel. The output is from 300 - 400 nanometers centered at 340 nm.

12

Gloss Retention & Yellowing Resistance

Gloss: ASTM D523-89 @ 60°

Yellowness Index: ASTM E 313-98

13

Gloss Retention Rating Scale

!   Good = 0‒7 points of gloss loss

!   Slight = 8-15 points of gloss loss

!   Severe = >15 points of gloss loss

14

Degree of Micro-Cracking as it Relates to Oligomer, Film Thickness & QUV Exposure

Oligomer& Film

Thickness

0 QUV

100 Hours

300 Hours

500 Hours

700 Hours

1000 Hours

1500 Hours

2000 Hours

3000 Hours

4000 Hours

5000 Hours

CN9006 5 micron

Good Good Good Slight Slight Slight Slight Severe Severe Severe Severe

10 micron Good Good Good Slight Slight Slight Severe Severe Severe Severe Severe

15 micron Good Good Slight Slight Severe Severe Severe Severe Severe Severe Severe

CN9025 5 micron

Good Good Good Good Good Good Good Good Good Good Slight

10 micron Good Good Good Good Good Good Slight Severe Severe Severe Severe

15 micron Good Good Good Good Good Slight Severe Severe Severe Severe Severe

CN9026 5 micron

Good Good Good Good Good Good Good Good Good Good Good

10 micron Good Good Good Good Good Good Good Good Good Good Good

15 micron Good Good Good Good Good Good Good Good Good Good Good

CN9013 5 micron

Good Good Good Good Good Slight Severe Severe Severe Severe Severe

10 micron Good Good Good Good Good Slight Slight Severe Severe Severe Severe

15 micron Good Good Slight Severe Severe Severe Severe Severe Severe Severe Severe

15

Urethane Acrylate Hard Coat Summary

!   Aliphatic urethanes with high acrylate functionality result in cured films having excellent abrasion resistance properties.

!  Higher functionality yields a higher crosslink density, which, in general, is desirable. However, the downside of increased crosslink density can be a decrease in abrasion resistance and an increase in micro-cracking of the cured film during weathering exposure, particularly when coating thickness exceeds 5 microns.

!  These limitations can be controlled by modification of the backbone structure to impart increased flexibility or by the addition of lower functionality acrylates to the formulation to reduce crosslink density.

!  These adjustments improve the ductile properties of the film making it more malleable, resulting in cured film with better abrasion resistance and a lower propensity for micro-cracking during weathering.

16

Barrier Properties of a Hard Coat Formulation

Test Methods & Results

17

Weathering Resistance of a Coating on Polyester Film ∆E and Gloss Loss as it Relates to QUV Exposure

Base Formulation Cure & Application Parameters

1) Two 400 W/in “H” Lamps @ Line Speed 50 F/M

2) Power Puck UVA,1.8 J/CM2

3) Film thickness: 5-7 microns, Applied using a # 4 wire bar

4) Viscosity @25C, 820 cps

Component Weight%

CN9026 75.0

Flexible Monofunctional Acrylate

12.0

Low Surface Tension Monofunctional Acrylate

10.0

Irgacure 184 3.0

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Test Method Employed, ∆E Measurements

!   BYK Color-Guide Sphere ●  CIE Lab ●  YE313-98 ●  D65/10

!   Readings taken on coated 5 mil thick PET placed over a white background for measurement

!   ∆E is measure of overall color change

19

∆E Test Results as They Relate to QUV Exposure & Stabilizer Package Used

0.00  

1.00  

2.00  

3.00  

4.00  

5.00  

6.00  

7.00  

8.00  

9.00  

100   300   500   700   900   1100   1300   1500   1700   1900  

Delta

 E  

Hours  of  QUV  Exposure  

PET  

FormulaBon  on  PET  

1.5%  UR-­‐210  

3.0%  UR-­‐210  

1.0%  292  ;  1.0%  400  

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Gloss Retention @ 60 as it Relates to QUV Exposure & Stabilizer Package Used

5  

25  

45  

65  

85  

105  

125  

145  

165  

185  

205  

0   200   400   600   800   1000   1200   1400   1600   1800   2000  

Gloss  

Hours  of  QUV  Exposure  

PET  FormulaBon  on  PET  1.5%  UR-­‐210  3.0%  UR-­‐210  1.0%  292  ;  1.0%  400  

21

UV/VIS Percent Transmittance After 2000 Hours QUV Exposure

0

10

20

30

40

50

60

70

80

90

100

0 100 200 300 400 500 600 700 800 900 1000 1100 1200

Nanometers

Perc

ent T

rans

mitt

anc

e

PET Only

Coated PET

Coating w/ HALS on PET

22

Barrier Property Performance Observations

!   Certain grades of PET will degrade when exposed to heat, light and moisture for extended periods.

!   A properly formulated coating can lessen the degradation and protect the PET.

!   The addition of HALS and light absorbers can further enhance protection.

23

Polyurethane Dispersion Product Study

Overall Properties &

Abrasion Resistance Study

24

Liquid Property Overview of UV-Curable Waterborne Oligomers, Polyurethane Dispersions (PUD)

Product Designation

Percent Solids Viscosity @ 25 C, cps

pH

Mean Particle Size (nm)

NTX12784 39-41 10-12 7.3 ‒ 8.0 125

CN9500 40-42 8 - 15 7.3 ‒ 7.9 120

CN9501 39-41 10-12 7.2 ‒ 7.9 140

Control 35 20 8.0 <150

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Waterborne Oligomer Testing, Formulating and Processing

!   Formulation: UV-PUD diluted to 35% solids plus standard additives and photoinitiators

!   Film Thickness: 6.0 mils wet/2.0 mils dry

!   Substrates: Glass (hardness and tensile), Leneta charts (KCMA stain), aluminum panels (MEK resistance and Taber abrasion)

!   Drying Conditions: 30 min @ 72oF/50% RH, 30 min @ 60oC

!   Cure Conditions: 2 x 400 W/in. Hg lamps @ 50 ft/min

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PUD Test Results

Relative Performance Ranking5 = Best

0 1 2 3 4 5

Hardness

Solvent Resistance

Water Resistance

Stain Resistance

Abrasion Resistance

QUV Yellowing

Flexibility

   Control   Aquamer  9501 Aquamer  9500 NTX12784

27

Waterborne Oligomer Testing

Surface Scratch Testing

!   Affix white abrasive pad to a mounting fixture having an area of 1 sq. in.

!   Place 100g weight on top of mounting fixture.

!   Slide weighted pad back and forth over the surface 50 times at each weight load.

!   A back and forth motion constitutes one cycle.

!   Measure gloss before and after abrading.

!   Report gloss readings.

Gloss Retention

6065707580859095

100 200 300 400 500

 Double  Rub  Cycles

Gloss  @

 60

Control  PUD

CN9501

28

Taber Abrasion Resistance, CS 17, 1000g Load

0

13

24

33

42

49

0

915

2529

32

0

9

18

29

36

45

0

10

20

30

40

50

60

0 200 400 600 800 1000

Taber  Cycles

Weight  Loss,  milligrams

NTX12784

CN9500

CN9501

Control

29

Waterborne Oligomer Observations

!   The family of UV-PUD materials examined offers a higher reactive solid content at a lower viscosity when compared to typical UV-PUDs on the market.

!   These features provide greater formulating latitude for industrial coatings.

!   When compared to the control UV-PUD, enhanced surface scratch resistance, flexibility, yellowing upon QUV exposure, and abrasion resistance are noted for the UV-PUDs studied.

!   The UV-PUD oligomers show excellent water resistance. For example, no whitening of any of the cured films was noted after surface exposure to hot water.

!   The QUV accelerated weathering results for the UV-PUD oligomers are excellent. These materials have comparable weathering resistance to those of an aliphatic urethane.

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Thank you

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