The Right Choice. - Pressure Sensitive Tape Council Sean.pdf · Weatherability Testing A tool for...

The Right Choice.

Natural Exposure Testing VS

Accelerated Weathering...

The Most Trusted Name In Weathering

© 2007 Q-Lab Corporation

Cleveland,Ohio

Headquarters &

Instrument Division

Bolton, England

Q-Lab Europe

Founded in 1956

Specialize in material durability testing equipment

and services

Shanghai, China

Q-Lab China

Saarbrücken Germany



Miami, Florida Phoenix, AZ

Q-Lab Weathering Research Services

Weatherability Testing

A tool for improving

product durability

A tool for decision making



Case Study

Large manufacturer of full product line of pressure sensitive tapes

Concerned about degradation of adhesive, backing, and, in some products, color

Various adhesive chemistries

Tests both outdoor “durable” and general use tapes

Testing is performed for R&D



Know Your Enemy

Sunlight

Temperature

Moisture

Other factors



Spectrum

of

Sunlight

Irradiance:

The rate at which light energy falls on a

surface, per unit area; W/m2

ASTM G113 -Terminology



Summer Sunlight Standard

250 350 450 550 650

0.0

0.5

1.0

1.5

2.0

Wav elength (nanometers)

Irra

dia

nc

e

W/m

2/n

m

Visible LightUV Region

UV

-A

UV

-B

UV

-C

0.68 W/m2 at 340 nm



Short Wavelengths - Polymer

Degradation

Long Wavelengths - Fading &

Color Change



Seasonal Variation

Intensity changes 8:1 @ 320 nm

Cut-off shifts from 295 to 310 nm

Summer

Winter



Temperature



Thermal Cycling Effects

Physical stress

Coatings on plastics

Assemblies

Darker Color = Higher Temperature

Fischer and Ketola, 1993



Moisture



Q-Lab’s TOW Research

Things Are Wet Outdoors Longer Than You Think



TOW vs. Rainfall - Miami, FL

Don’t Underestimate the Effect

of Moisture

Changes The Rate

Changes Mode Of Degradation

Difficult To Accelerate



Exposure Locations

Florida subtropical

Arizona desert sunshine

Others

(www.q-lab.com for climate data)



Accelerated Outdoor



0

2

4

6

8

10

12

250 350 450 550 650 750

Wavelength (nm)

Irra

dia

nce

(W

/m²/

nm

)

Summer Sunlight

Q-Trac

Summer Sunlight vs. Q-Trac



Outdoor Techniques Offer The Closest

Simulation to Your Service Environment

But remember:

Weather varies greatly

Outdoors is best...

But who can wait?

Use Florida & Arizona,

PLUS an accelerated test



Accelerated Lab

Weathering

All Weathering Testers Are

Screening Devices

No Perfect Simulation



Xenon Arc Spectra

filtering

irradiance level

control point



SPD's of Q-Sun and UVA-340 Lamps vs. Sunlight

0.0

0.5

1.0

1.5

2.0

2.5

3.0

250 300 350 400 450 500 550 600 650 700 750 800

Wavelength (nm)

Irra

dia

nc

e (

W/m

²/n

m)

Xenon With Daylight Filters

Sunlight

Xenon with

Daylight Filters



0.0

0.2

0.4

0.6

0.8

1.0

1.2

260 280 300 320 340 360 380 400

Wavelength (nm)

Irra

dia

nc

e (

W/m

²/n

m)

Xenon with Daylight Filters

Xenon with

Daylight Filters

Sunlight



0.0

0.5

1.0

1.5

2.0

2.5

3.0

250 300 350 400 450 500 550 600 650 700 750 800

Wavelength (nm)

Irra

dia

nc

e (

W/m

²/n

m)

Xenon with Window Glass Filters

Xenon with Window

Glass Filters

Sunlight

Through

Window Glass

Sunlight



0.0

0.2

0.4

0.6

0.8

1.0

1.2

260 280 300 320 340 360 380 400

Wavelength (nm)

Irra

dia

nc

e (

W/m

²/n

m)

Xenon with Window Glass Filters

SunlightSunlight Through

Window Glass

Xenon with

Window

Glass Filters



Temperature Control

Temperature & Color




Xenon Arc Summary

full spectrum - UV, Visible, IR

best simulation of long wave

UV & visible

calibration

water spray

relative humidity control



UV Fluorescent

Weathering

TesterIntroduced 1970

model QUV/spray

ASTM G154



Specimen Holders



0.0

0.2

0.4

0.6

0.8

1.0

1.2

270 290 310 330 350 370 390

Wavelength (nm)

Irra

dia

nc

e W

/m²/

nm

UV-B Lamps

FS-40 Lamps

UVB-313 Lamps

Sunlight



UVA-340 Lamps

0.0

0.2

0.4

0.6

0.8

1.0

1.2

260 280 300 320 340 360 380 400

Wavelength (nm)

Irra

dia

nc

e (

W/m

²/n

m)

Sunlight

air mass=1.0

(CIE 85 table 4)

QUV with UVA-340 lamps

0.68 W/m2 @ 340 nm

UVB-313 Lamps QUV/se

0.0

0.2

0.4

0.6

260 280 300 320 340 360 380 400

Wavelength (nm)

Irra

dia

nce (

W/m

²/n

m) 5,600-hour lamps

2-hour lamps



0.0

0.5

1.0

1.5

270 290 310 330 350 370 390

Wavelength (nm)

Irra

dia

nce

(W

/m²/

nm

)

Effect of Intensity UVA-340

Intensified 75%

Typical Intensity

Sunlight

Speed vs. Realism

increasing the stresses often

decreases correlation



Fluorescent Lamp Advantages

fast results

very stable spectrum

minimal maintenance

simple calibration

low cost



QUV Moisture

condensing humidity

water spray



QUV

Condensation



Condensation Advantages

identical to natural wetness

elevated temperature

pure water

easy to use

Temperature & Color




QUV vs. Q-Sun

UVA-340 best simulation

of shortwave UV

UVB-313 might be too severe

no visible light

stable spectrum

irradiance control

no RH control

water spray or condensation

full spectrum

best simulation of long wave

UV & visible light

spectrum changes

irradiance control

relative humidity control

water spray



QUV, Xenon, Sunlight...

0.0

0.5

1.0

1.5

2.0

2.5

3.0

250 300 350 400 450 500 550 600 650 700 750 800

Wavelength (nm)

Irra

dia

nc

e (

W/m

²/n

m)

Q-Sun with Daylight Filters0.68 W/m2 @ 340 nm

Sunlightair mass=1.0 (CIE 85 table 4)

QUV with UVA-340 lamps0.68 W/m2 @ 340 nm



Xenon arc is Best For Testing

Lightfastness / Color

Degradation



QUV Is The Best For Polymer

Degradation

gloss loss

yellowing

chalking

checking

adhesion

cracking

tensile

strength

loss

Impact

resistance



UVA-340 Is the Best Available

Simulation of Short-Wave UV



Case Study

QUV

Tests adhesive and also the backing facing the light

Uses 12” x 9” glass substrates

5 pull-downs per specimen

1 pull down per time interval

Generates time degradation curves



Case Study

QUV material failure modes

Adhesive residue left on glass

Tape locks down on glass, falls apart when removed

QUV Test Cycles

72 to 96 hours is usually enough to tell a good material from a bad one

Uses various custom cycles



Case Study

Q-Sun Xenon Test Chamber

Used when color is a concern, usually for duct

tapes

Sometimes used to test adhesives of less durable

materials; similar results to QUV

Results typically take longer than QUV for

adhesive and backing tests

Custom cycles, plus ASTM D6551



Case Study-- Conclusions

Results are comparative

Degradation modes are correlated to

outdoor testing

Acceleration factors are not considered

accurate “because weather varies so

much”



Case Study-- Conclusions

Benefits of Test Program

Data is used to make good decisions

Materials

Processes

Question: any stories to tell about product

failures or catastrophes avoided?

“We haven’t had any as far as I know.”



Case Study – Lessons Learned

Define modes of degradation and test for each (color change, adhesive degradation, backing degradation)

Define failure end-point

UV fluorescent and xenon each have strengths

Comparisons using rank order are very powerful!

Must use outdoor testing to validate lab results

Faster than you think!

Inexpensive!



Case Study – Opportunities

Use control specimens

Use a well-understood good performer

Learn from failures, retain a well-

understood poor performer

Develop time degradation curves for each

control

Laboratory AND outdoor



Ideal Test Program

Outdoor weathering in FL, AZ, or both

Real world data

Correlation

Accelerated weathering in UV fluorescent, Xenon, or Fresnel

Concentrator or a combination

Fast results

Formulation changes

QC

Questions ?

The Right Choice. - Pressure Sensitive Tape Council Sean.pdf · Weatherability Testing A tool for...

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