"Finishing Technology for Consumer Electronics: A Manufacturer’s Perspective" given by James Wrezel, Bing Diao & Sarah Severson from Motorola Mobility LLC, a Google Company. The presentation was given at RadTech UV & EB Technology Expo & Conference 2014. To learn more about UV and EB Curing Technology, visit http://www.radtech.org.

1. Finishing Technology for Consumer Electronics:
A Manufacturer’s Perspective
James Wrezel, Bing Diao & Sarah Severson
Motorola Mobility LLC, a Google Company
RadTech UV/EB 2014 Technology Expo & Conference
May 12 – 14, 2014
Chicago, IL

2. 2Page
Introduction
• Our mission is to connect millions of people with affordable
devices that don’t compromise on quality, experiences or
style. Every time someone powers on a Motorola device, we
like to think it's charging up the world — making someone
smile, say "wow," get a little more out of their day.
• Coatings are creating the quality look and feel in a device
that is affordable
• Delighting the consumer with attractive materials, surfaces
and coatings that promote a feeling of quality and a device
that is something special and personal
• Growing desire for housing interchangeability &
personalization
• UV coatings allow us to vary the user experience and
provide color, gloss and haptic options which are production
capable

3. 3Page
So Why UV-Curable Coatings?
Property Advantages
Scratch Resistance Better than 2K PU Coatings
Yellowing Better than 2K PU (appropriate photoinitiator)
Perceived Quality Appearance, Feel, Color Depth
Testing Rapid Cure, No Post Cure
Yield Reduced FM Contamination
Handling / Packaging Hardness and Fast Property Development
Coating Adaptability Monocoat & Base/Clear
Mixing / Pot Life Long Pot Life
Fat Edge / Orange Peel Reduced vs. 2K PU Coatings

4. 4Page
Critical UV Coating Performance Testing
Paint Supplier and Component Specifications
require conformance to appropriate
specifications which translate to a high quality
product for the consumer
• Pencil Hardness & Scrape Resistance
• Abrasion Resistance – Static and Dynamic Load
• Cross-Cut Tape Adhesion
• Chemical Resistance – Solvents & Staining Media
• Color & Gloss – Spectrophotometer and Gloss Meter

5. 5Page
Topics
• Full Gloss UV Clearcoat Composite Housings
• Low Gloss UV Clearcoat – Mar Resistance
• Low Gloss UV Clearcoat – Production Issues

6. 6Page
Full Gloss UV Clearcoat Composite Housings
• Full gloss UV coatings enable a high quality finish suitable for specific end-users
and premium products
• Concerns for the implementation of full gloss UV surface decoration
- scratch resistance
- thermal stability
- cleanability
- printability
• Early testing identified a performance risk due to the ease of scratching and gloss
reduction that would be deemed objectionable to the consumer and lead to early
life failures
Microscratching
obvious at
various viewing
angles
Gloss reduced
from abrasion

7. 7Page
Scratch Resistance Characterization – Steel Wool
• Measurement of gloss change as a function of steel wool reciprocating cycling
• Engaged multiple UV coating suppliers to develop improved scratch resistant
finishes that exceeded the performance of their standard coatings
Linear Taber
Scratch Test Using
Steel Wool

8. 8Page
Scratch Resistance of Different UV Clearcoatings
0
10
20
30
40
50
60
70
80
90
100
0 5 20 50 100 160
GlossChange
Steel Wool Cycles
GlossChange vs. Steel Wool Cycles
Competitor
Normal PU
Normal UV
Droid Ultra
• An improved full gloss UV scratch resistant clearcoat was identified which
exceeded the performance of existing coatings and competitive products
• The coating system is processable using conventional UV lamps and
compatible with basecoats and surface primers. Multiple coating applicators
have been introduced to this coating system in mass production.

9. 9Page
High Gloss Surface Cleanability
WCA
Reference Improved
1 88.4 111.0
2 86.9 112.1
3 80.3 123.0
4 99.7 109.0
5 86.6 108.0
Avg. 88.4 112.6
• Full gloss UV coatings can offer the
consumer advantages in cleanability
when combined with anti-smudge
additives
• Such coatings can be tested in a variety
of ways depending on use conditions
• Water and other liquid contact angle
measurements can be used to
characterize the coated surface
WCA = 88.4
Good Wetting
WCA = 112.6
Poor Wetting
Greater water contact angle (WCA)
provides a surface that is easier to clean

10. 10Page
High Gloss Clearcoat Printing
• Personalization is driving the requirement for post-processing, including pad
printing
• Regulatory and carrier logos require similar level of decoration performance and
reliability as the UV clearcoat
New test methods developed
to replace subjective test
methods, including localized
scrape and mar resistance
Poor scratch resistance of pad
printing observed with UV
clearcoat + anti-smudge additive

11. 11Page
Low Gloss UV Clearcoats – Mar Resistance
• Mar resistance is critical for low gloss UV clearcoats as gloss changes can be
observed with consumer use
• Early supplier involvement is required to ensure performance meets requirements
0
1
2
3
4
5
6
0 10 20 40
GlossChange
Steel Wool Cycles
GlossChange vs. Steel Wool Cycles
Supplier A - 8 Gloss
Supplier B- 8 Gloss
Original
User Trial
Steel Wool Performance Testing

12. 12Page
Low Gloss Basecoat / UV Clearcoat System – Tumbler Testing
Gloss 1-2 Gloss 4-6
Tumbler testing identified surface staining and marring which was gloss
dependent even within desired scope of a “low gloss” surface finish

13. 13Page
Color (description)
Basecoat Thickness
(Spec = 8-13 microns)
Clearcoat Thickness
(Spec = 10-15 microns)
White – Good (4-6 gloss) 8 – 10 10 – 12
White – Failure (1-2 gloss) 6 – 10 5 - 8
Good White (1000X) – Smooth, even
clear coat
Bad White (1000X) – Rough, thin clear
coat
Substrate
Substrate
Base coat Base coat
Clear coat
Clear coat
Low Gloss Basecoat / UV Clearcoat – Coating Thickness
Maintaining proper UV clearcoat thickness is critical, as well as surface roughness

14. 14Page
Low Gloss Basecoat / UV Clearcoat – Clearcoat FTIR Analysis
• Greater surface organic-to-filler ratio can reduce marring in low gloss coatings
• Basecoat gloss may require abnormally high levels of matting agent in the UV
clearcoat vs. that required in a one-coat system to meet clearcoat gloss targets
• Possible interaction between basecoat & clearcoat from basecoat drying conditions
Gloss
IRIntensity
1720cm-1 vs1060 cm-1
1720cm-1 1060cm-1
Bad Paper White 1-2 0.543 0.876 0.62
Good Paper White 4-6 0.871 0.892 0.98
Known Reference 1-2 0.826 0.904 0.91
Substrate Gloss Reading
Plastic 9
Basecoat 29-31 (Line A)

15. 15Page
Low Gloss UV Coatings – Gritty Surface Texture
Gritty area below M-logo
Turquoise “Grit” – 400X
Matting
Agent
Solid Particle
• 45 micron solid debris particle
observed
• Good part cleaning and UV clearcoat
filtration needed

16. 16Page
Low Gloss UV Clearcoats – Plastic Contamination
• Fingerprint marks observed after temperature/humidity exposure. No impact to
cross-cut adhesion.
• Poor operator handling of phone housings during placement on painting jigs
• Important to wear proper gloves and handle parts by edges only

17. 17Page
Low Gloss UV Coatings – Pad Printing Adhesion
• A silver pad print ink was found to have poor scrape adhesion over a low gloss UV
clearcoat
• Ink supplier reformulated the ink for better UV coating adhesion
• Plasma treatments can offer improved ink adhesion when applied to fully cured UV
coatings
Cross-cut tape adhesion pad
printing failures
Improved pad printing adhesion

18. 18Page
Conclusions
• Full gloss UV coatings can provide high scratch resistance when
modified accordingly. Smudge resistance and easy cleanability need
improvement to promote personalization and regulatory marking.
• Pad printing needs to be developed for compatibility with UV clearcoats
for high field performance
• Mar resistance of low gloss UV coatings must be tailored to maximize
perceived quality and reliability
• Production problems with regard to coating filtration and plastic handling
must be offset with controlled processing and proper operator handling

19. 19Page
Future Development Needs in UV Coatings
• Anti-Smudge UV Clearcoats – Available option within a coating family
• Post-Processing – Suppliers should optimize coatings beyond typical
use conditions and consider that the coating itself may be a substrate
• Mar Resistant UV Clearcoats – Improved stain and gloss retention when
abraded
• Future UV coating system development requires careful thought for
plastic substrate interactions and use limits