Adhesives and Bonding Technologies for Multi Material Mix Design
Dr. Stefan Schmatloch Lead R&D Manager DOW Automotive Adhesives Dr. Sergio Grunder R&D DOW Automotive Adhesives Dr. Andreas Lutz R&D Director DOW Automotive Adhesives
Meyer Galow /
GDCh award for
BETAFORCETM
2015
R&D 100
Award for
BETAFORCETM
2016
Golden Mousetrap
Award
BETAFORCETM
2017
2018
Why Weight Savings?
global vehicles emissions legislation
powertrain improvements alone cannot achieve the fleet fuel efficiency and emissions targets
10% less mass up to +7% fuel efficiency
2
Source: www.icct.org
Source: www.icct.org
+
US Car Average
EU Car Average
CALIFORNIA
1500 2000 2500 3000 3500 4000 4500 5000 5500
Vehicle Mass (lbs)
US Lt Truck Avg.EU Average
EU Car Average
US Car Average
US Lt Truck Avg. Gasoline car
Diesel car
Gasoline Hybrid
Diesel Hybrid
EU 2020 targetCA 2020 target
EU 2015 target
US 2015 target
330
300
270
240
210
180
150
90
60
30
CO
2 E
mis
sio
ns g
/km
US Car Avg.
Industry Trend increasing usage of lightweight metals
DOW CONFIDENTIAL - Do not share without permission
bonded VORAFORCETM 5300 CFRP rear wall enables approx. 30% increase of torsional stiffness
BETAFORCETM 9050M continuous bond line results in significant improvement of crash resistance
4
industry trends CFRP
CFRP rear wall, www.audi-mediacenter.com
Structural Adhesive Technologies vehicle weight reduction by multi material design
5
Full Body Bonding Module Bonding Full Body Bonding
BETAFORCE™ Polyurethane Technology
Body Shop Paint Trim
Shop Repair 80-160°C, 30’ 180°C, 30’ 25°C
BETAMATE™ Epoxy Technology
tail gate and closure
applications: polypropylene and
SMC composite bonding
full car body assemble: high
performance composite to metal
bonding
battery assembly: thermal conductives
structural bonding and sealing
Audi A8 space frame design
D. Roquette, F. Meyer, L. Herbeck, High Volume
Manufacturing of Carbon Fiber Reinforced Plastic
Body in White, Automotive circle, Materialien des
Karosseriebaus, Bad Nauheim, 2017
Structural Adhesive Technologies
Increased Energy Management Capability continuous bond lines improved crash performance
Enabling Multi Material Mix Design for Light Weighting greater design flexibility
non-traditional materials
non-destructive joining technique, retained integrity of substrates
Weight Reduction optimized steel design (-20%)
aluminum intense design (- 40-50%)
carbon fiber intense design (-60%)
Enhanced Vehicle Performance increased static stiffness: 20%
increased dynamic stiffness: 2 – 3%
climate independent performance
Improved Manufacturing Processes fast low cost joining and DT curing elimination of surface pre-treatment processes process speed improvement of 50 -100%
Design
Safety
Environment
Savings
6
Durability &
Driving Comfort
800
400
100
50
35 30 25 20 15 10 5 1
Elongation %
Lap Shear Strength (Mpa)
Structural Epoxy Adhesives:
BETAMATE™
PU Adhesives & Sealants: BETASEAL™, BETALINK™
Semi-Structural PU Adhesives: BETAFORCE™
PU Sealants: BETASEAL™, BETAFILL™
Structural PU Adhesives: BETAFORCE™
Epoxy Adhesives:
BETAMATE™ Flex
Epoxy Hybrid Adhesives:
BETAMATE™
BETAFORCE™ Polyurethane Technology
Body Shop Paint Trim
Shop Repair 80-160°C, 30’ 180°C, 30’ 25°C
BETAMATE™ Epoxy Technology
Automotive Manufacturing Processes body shop vs. trim shop process materials
7
Adhesive Portfolio Meets Requirements
portfolio tailored to application needs
robust material properties over wide temperature range
long-term durability of bond assembly
combination of high modulus and high tensile strength despite high elongation at break
robust substrate bonding (e-coat, SMS, CFRP, etc.) for hybrid materials assembly
tailor made heat accelerated curing technologies
thermal conductive adhesives for structural battery assembly
8
open time at 23°C [min]
elongation at break
BETAFORCETM 2810LV plus
BETAFORCETM 2817 V1
BETAFORCETM 9050M
BETAFORCETM 2806
BETAFORCETM 2800 TC
ela
sti
c m
od
ulu
s [
MP
a]
9
Improved Physical Properties for Driving Comfort ambient climate independent adhesive joint properties
high bulk property performance (modulus, tensile strength) and durable adhesion performance enable
multi material mix design and contribute to overall part and vehicle stiffness
conventional adhesive technology
change of physical properties after exposure (temperature and humidity)
change of physical properties under dynamic load
0
2
4
6
8
10
12
14
16
18
0 20 40 60 80 100
sh
ea
r s
tren
gth
[M
Pa
]
exposure times [days]
CFRP BETAFORCE(TM) 9050M e-coat BETAFORCE(TM) 9050M
conventional adhesive
150
200
250
300
350
400
0 2 4 6 8
mo
du
lus
[M
Pa
]
exposure time [days]
BETAFORCE(TM) 9050M conventional technology
exposure: 70C water immersion, -20C freeze shock. exposure: climate change cycle beween -30C and 80C.
< 20% change
< 20% change
BETAFORCETM 9050M
10
Improved Curing Kinetics for Manufacturing Process Optimization latency & humidity independent curing – flexible logistic processes
0
20
40
60
80
100
120
140
160
0 50 100 150 200 250 300
mo
du
lus
[M
Pa
]
curing time [min]
manufacturing processes may require part shipment or part handling shortly after adhesive joining in
uncontrolled climate conditions
conventional adhesive technology
need for additional mechanical fixations
need for long curing time to reach end-cure properties or handling strength (modulus and shear strength)
fast curing only in combination with short open times (no latency)
BETAFORCETM 9050M latency
slow initial cure at low viscosities followed by
rapid cure at ambient temperature to reach
end cure properties after short curing times
11
0.00
2000.00
4000.00
6000.00
8000.00
10000.00
12000.00
14000.00
16000.00
18000.00
0 500 1000 1500
co
mp
lex
vis
co
sit
y [
Pa
.s]
time [sec]
Improved Curing Kinetics for Manufacturing Process Optimization latency & heat cure – flexible manufacturing processes
heat accelerated cure
latent curing kinetics
low press-in forces to reach targeted bond gap thickness
also after long open and assembly times
flexible assembly processes
heat accelerated processes fast obtained handling
strength and for very short takt times
good adhesive bead compressibility with increasing
curing time with latent BETAFORCETM technologies
poor adhesive bead compressibility with conventional
adhesive technologies
12
latent curing kinetics and shear thinning properties contribute to robust application processes
with prolonged mixer dwell times
without frequent change of static mixers (waste reduction)
enabling reduction of flush cycles (waste reduction)
with robustness over a wide range of material and ambient temperature
with stable application pressures and robust application processes
Improved Latency for robust Application Processes
0
10
20
30
40
50
60
0 20 40 60 80ap
plic
ati
on
pre
ss
ure
[b
ar]
No of applications without mixer flushing
peak pressure POLY peak pressure ISO
application pressure POLY application pressure ISO
Left. good mixing quality.
Right. poor mixing quality.
excellent adhesion performance
as result of robust applicability
13
Improved Adhesion for Manufacturing Process Optimization reduction of surface pretreatment processes
adhesion to carbon fibre re-enforced plastics (CFRP)
removal of mold release agents necessary in order to obtain robust adhesion
conventional adhesive technology
need for complex cleaning processes: grinding, korund (Al2O3) blasting processes followed
by removal of dust via washing or vacuum
need for difficult quality control for mechanical cleaning processes
need for application of additional adhesion promoters
BETAFORCETM 9050M
improved adhesion performance for simplified processes without the need for mechanical,
physical or chemical activation of the bond line
poor wetting and resulting adhesive failure
to CFRP of conventional adhesives
good adhesion performance of BETAFORCETM
9050M to washed CFRP substartes
14
Improved Adhesion for Manufacturing Process Optimization CFRP wash process
0.00
5.00
10.00
15.00
20.00
25.00
0 50 100 150 200
sh
ea
r s
tren
gth
[M
Pa
]
curing time [h]
CFRP grinded, 1x CFRP heptane clean, 1x CFRP water wash, 1x
0.00
5.00
10.00
15.00
20.00
25.00
0 50 100 150 200
sh
ea
r s
tren
gth
[M
Pa
]
curing time [h]
CFRP grinded, 2x CFRP heptane clean, 2x CFRP water wash, 2x
0
5
10
15
20
25
0 50 100 150 200
sh
ea
r s
tren
gth
[M
Pa
]
curing time [h]
CFRP grinded, 10x CFRP heptane clean, 10x CFRP water wash, 10x
mold release study
CFRP surface contamination with up to 10 fold
access of mold release
robust adhesion, unchanged curing kinetics and
end cure properties independent from cleaning
process: mechanical grinding vs. heptane
cleaning vs. water wash process
confirmed long term durability of bonded joints