QUALIFICATION TEST FOR A/C PANEL ADHESIVES

1
QUALIFICATION TEST FOR A/C PANEL ADHESIVES
2
Establish similarity of bonded details.
OBJECTIVE
Develop a qualification test for flammability of
adhesives used in bonded details.
PURPOSE
APPLICATIONS
Certification of New Parts
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ADHESIVES TASK GROUP
3MAmerican AirlinesBoeingBombardierBostikCD
AerospaceDassaultFAAHenkel
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INDUSTRY-PROPOSED METHODS OF COMPLIANCE FOR
CERTIFICATION OF INTERIOR MATERIALS
Part 2 Methods That Will Require Supporting Data
25.853(a) Bunsen Burner Similarity
25.853(d) Heat and Smoke Similarity
Ref. No.
Feature / Construction
Test required if A gt 2 ft2 Possible Test if 1 lt
A lt 2 ft2 No test required if A lt 1 ft2
Testing detail without adhesive to Appendix F
substantiates the bonded configuration
BONDED DETAILS
28
For FAA Qualified Adhesives?
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ADHESIVE QUALIFICATION TEST ISSUES
FAR 25 versus Other Measurement MethodSample
FormEffect of AdherendsEffect of Thickness
Does thinner substantiate thicker?
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Example Thermoplastic Thickness Ranges
Peak HRR
Proposed range
Peak Heat Release Rate, kW/m2
Total Heat Release, kW-min/m2
Total Heat Release
EUROPLEX PPSU Clear
0
.040
.080
0.12
0.16
0.20
0.24
0.28
Thickness, inches
OSU Peak HRR of 0.040? does not substantiate
.080?- 0.16?
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Standard Test Method for Measuring Flammability
Properties of Plastics and Other Solid Materials
Using Microscale Combustion Calorimetry, ASTM D
7309
Oxygen Inlet
Scrubber
Flow Meter
Combustor
O2 Sensor
Mixing Section
Exhaust
Sample Cup
Pyrolyzer
Purge Gas Inlet
Sample Post Thermocouple
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THERMAL COMBUSTION PROPERTIES FROM MCC
Peak Heat Release Rate Heat Release Capacity
(J/g-K)
?c
hc
Total Heat Release (J/g)
Heat Release Rate (J/g-K)
Tp
? Burning Temperature
? Noncombustible Fraction (g/g)
250
300
350
400
450
500
550
800
850
Temperature (C)
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HEAT RELEASE CAPACITY VERSUS COST OF PLASTICS
1000
Commodity Plastics
PE
PP
PMMA
ABS
PS
NYLON 66
Epoxy
PU
PET
PAR
PPO
Engineering Plastics
PSU
POM
PC
PES
PVF
PPS
PVC (rigid)
Heat Release Capacity (?c), J/g-K
PEEK
Phenolic
100
Heat Resistant Plastics
LCP
PEI
PEK
PPSU
TYPICALLY PASS FAA HRR TEST
PAI
KAPTON
10

1
10
100
0.1
Materials Cost (/lb)
Truckload Prices, 2001
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VERTICAL BUNSEN BURNER TEST (114 plastics)
Probability of Passing the UL 94 V-0 Requirement
ASTM D 3801
Probability of Passing VBB, p
? 448 J/g-K n 4.46 R 0.97
Heat Release Capacity ?c, J/g-K
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HAND LAY-UP OF ADHESIVE / RESIN OSU SAMPLES

• Fiberglass-reinforced adhesive samples are made
  by hand lay-up.
• Samples cured between two Teflon-coated aluminum
  plates in heated press.
• Cured samples trimmed to 6? x 6? for OSU HRR
  testing.
• Resulting samples 40 resin by weight.

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OSU TESTING OF ADHESIVE RESINS
Peak HRR
2-min HR
Resin
(kW-min/m2)
(kW/m2)
44
111
BPA Epoxy
26
88
BPAE MDA
28
72
BPA CE
28
48
BPC Epoxy
12
33
Silicone Resin
13
13
BPC CE
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OSU PHRR (binned data) 101 RESINS AND PLASTICS)
Maximum Heat Release Capacity from Curve Fit
(R 0.8264)
avg ?pHRR?, kW/m2
??c?, J/g-K
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?c
pHRR
y
??c?
p P/(P F)
OSU Data for AIRCRAFT CABIN MATERIALS
1 9 10 13 15 22 29 50 105 108 115 120 120 121 121
127 129 136 140 141 152 153 155 156 159 173 192 19
6 201 203 215 215 230 235 248 261 265 276 295 298
301 316 345 349 359
8 25 59 13 66 31 55 30 54 92 61 49 123 60 52 109 6
4 65 69 110 90 30 85 45 72 106 36 32 74 65 213 150
97 258 55 44 188 199 93 211 232 166 115 207 90
P P P P F P P P P F P P F P P F P P F F F P F P F
F P P F P F F F F P P F F F F F F F F F
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9/10 0.90
127
6/10 0.60
Transform Quantitative Data into Qualitative Data
Using Pass/Fail Criterion
3/10 0.30
174
14 CFR 25.853

• HRR ? 65 kW/m2 Pass P
• HRR gt 65 kW/m2 Fail F

254
4/10 0.40
0/10 0.00
355
Etc.
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OSU PHRR (101 RESINS AND PLASTICS)
Probability that pHRR ? 65 kW/m2
14 CFR 25
Probability of Passing OSU pHRR, p
102 J/g-K
? 140 J/g-K n 2.4 R 0.97
Heat Release Capacity (?c), J/g-K
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EFFECT OF ADHERENDS and THICKNESS (Additive
Approach Using MCC Data)
?construction mp?p ma?a ms?s
?p , ?p
Part
?a , ?a
Adhesive
?s , ?s
Substrate
?i Areal Density of Layer i, g/m2 ?i Heat
Release Capacity of Layer in MCC i, J/g-K mi
Mass Fraction of Layer i ?i /??i
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EFFECT OF ADHERENDS and THICKNESS (ThermaKin
Numerical Burning Model)
Transient energy and mass balance calculation
Ti, ? , hc, E, A, etc.
Part
Ti, ? , h, E, A, etc.
Adhesive
Ti, ? , h, E, A, etc.
Substrate
Ti Thickness of Layer i, cm ?i Density of
Layer i, g/m3 hi Heat Release of Layer, J/g Ei
, Ai Thermal Decomposition Kinetic Parameters
of i
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OSU HRR OF BONDED CONSTRUCTION (ThermaKin
Simulation)
Heat Flux 35 kW/m2 (OSU) 15 kW/m2 (Flame)
Substrates 1/16? (1.5 mm) Thick Charring
Plastic (Polycarbonate)
Adhesive Layer Thickness 0.2, 0.5, 1 and 1.5
mm hc 2X Substrate
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OSU HRRs of BONDED CONSTRUCTIONS (ThermaKin)
0.2 mm Adhesive Layer
0.5 mm Adhesive Layer
HRR (arbitrary units)
HR (arbitrary units)
Time, min
Time, min
1.5 mm Adhesive Layer
1 mm Adhesive Layer
Time, min
Time, min