KIT – The Research University in the Helmholtz Association
1IHM, Karlsruhe Institute of Technology (KIT), Kaiserstr. 12, 76131 Karlsruhe, Germany2Carl Meiser GmbH & Co. KG, Stadionstr. 75, 72461 Albstadt, Germany
www.kit.edu
Model of microwave assisted thermal adhesion of synthetic leather to a plastic substrate
Sergey Soldatov1, Jens Meiser2 ,Benjamin Lepers1, Guido, Link1 and John Jelonnek1
Institute for Pulsed Power and
Microwave Technology
2 21.10.2016 S. Soldatov, Model of microwave assisted thermal adhesion of synthetic leather to a plastic substrate, COMSOL Conference, München, 2016
Outline
Motivation
Materials dielectric characterization
Electromagnetic modelling
Heat transfer model (COMSOL)
Optimization
Conclusions
http://www.frimo.com/de/produkte
http://www.frimo.com/de/produkte
Institute for Pulsed Power and
Microwave Technology
3 21.10.2016
Motivation
𝑃𝑎𝑏𝑠 = 2𝜋𝑓휀0휀′ tan 𝛿 𝐸𝑟𝑚𝑠2
Dielectric properties of materials are to be known
HEPHAISTOS Oven http://www.voetsch-ovens.com/en/products/industrial_microwave_system/schunk01.c.59509.en
S. Soldatov, Model of microwave assisted thermal adhesion of synthetic leather to a plastic substrate, COMSOL Conference, München, 2016
Institute for Pulsed Power and
Microwave Technology
4 21.10.2016
Heat balance
20C
20C
120C
qconvCooling
Heating
𝑞𝑐𝑜𝑛𝑣 = ℎ 𝑇𝑠𝑢𝑟𝑓 − 𝑇𝑎𝑖𝑟 𝑊 𝑚2
𝑝𝑎𝑏𝑠 =1
2𝜔휀0휀𝑟
′′ 𝐸 2 𝑊 𝑚3
𝝆𝑪𝒑𝝏𝑻
𝝏𝒕= 𝜵 ∙ 𝒌𝜵𝑻 + 𝒑𝒂𝒃𝒔
Heat source
S. Soldatov, Model of microwave assisted thermal adhesion of synthetic leather to a plastic substrate, COMSOL Conference, München, 2016
Institute for Pulsed Power and
Microwave Technology
5 21.10.2016
Materials dielectric properties versus temperature
Materials:
Adhesive: Hot melt polyurethane
(HMPUR) blended by carbon
particles
Substrate: ABS-PC
Coating: artificial PVC leather with
textile layer at wrong side
Materials were characterized with
cavity perturbation method and within
working temperature range
Absorption of microwaves in adhesive is predominated!
S. Soldatov, Model of microwave assisted thermal adhesion of synthetic leather to a plastic substrate, COMSOL Conference, München, 2016
Institute for Pulsed Power and
Microwave Technology
6 21.10.2016
Electromagnetic Modelling (CST wave Studio.)
Geometry of task. Coating-glue-substrate sandwich
Electric field pattern.
~ 1 m
The aim to find dielectric heat sources in every material
S. Soldatov, Model of microwave assisted thermal adhesion of synthetic leather to a plastic substrate, COMSOL Conference, München, 2016
Institute for Pulsed Power and
Microwave Technology
7 21.10.2016
Absorbed microwave power density.
20 40 60 80 100 1200.1
1
10
Glue (co-phased)
Glue (random phasing)
Leather (co-phased)
Leather (random phasing)
Substrate (co-phased)
Substrate (random phasing)
p [
MW
/m3]
T [C]
The cross-link between antennas is negligable
magnetrons are independent (not locked)
the phasing is random
f=2.45 GHz
S. Soldatov, Model of microwave assisted thermal adhesion of synthetic leather to a plastic substrate, COMSOL Conference, München, 2016
Institute for Pulsed Power and
Microwave Technology
8 21.10.2016
Heat transfer problem (COMSOL )
S. Soldatov, Model of microwave assisted thermal adhesion of synthetic leather to a plastic substrate, COMSOL Conference, München, 2016
Institute for Pulsed Power and
Microwave Technology
9 21.10.2016
Geometry
synthetic leather
Substrate
Glue
The glue is patterned to cover a selected percentage of surface.
Restrict a geometry to a single glue volume.
Neglect the influence of neighboring glue volumes.
PVC leather
S. Soldatov, Model of microwave assisted thermal adhesion of synthetic leather to a plastic substrate, COMSOL Conference, München, 2016
Institute for Pulsed Power and
Microwave Technology
10 21.10.2016
Heat transfer model (COMSOL)
interlaced yarns
PVC dense
PVC foam
Air
Substrate
(ABS-PC)Symmetry Axis O
pe
n b
ou
nd
arie
s
-1 -0.5 0 0.5 1 1.5 2 2.5 3 3.5
3.5
3.0
2.5
2.0
1.5
1.0
0.5
0 10-3
10-3
Glue (HMPUR)
Air convection
Vacuum bag (PE)
Heat source in PVC
QPVC’’(t)
Heat source in glue
Qglue’’(t)
Heat source in substrateQABS’’(t)
S. Soldatov, Model of microwave assisted thermal adhesion of synthetic leather to a plastic substrate, COMSOL Conference, München, 2016
Institute for Pulsed Power and
Microwave Technology
11 21.10.2016
Properties of materials in the model
Domain
name
Density
[kg/m3]
Specific heat
cp,
[J/kg/K]
thermal
conductivity k
[W/m/K]
Latent
heat
[J/kg]
Thickness along Z
[mm]
PVC dense [7] 1200 1800 0.15 0.2125
PVC foam 800 900 0.10 0.2125
Interlaced yarns [8] 200 1200 0.04 0.475
Glue [5] 950 1500…1700 0.19 5*104 0.35
Substrate (ABS)[6] 1080 1300 0.19 2.5
Air 1 1000 0.026 0.35
S. Soldatov, Model of microwave assisted thermal adhesion of synthetic leather to a plastic substrate, COMSOL Conference, München, 2016
Institute for Pulsed Power and
Microwave Technology
12 21.10.2016
Heat transfer model with COMSOL (II)
10:32:30 10:33:00 10:33:30 10:34:00 10:34:30
0
20
40
60
80
100
Te
mp
era
ture
, C
time
"2" between Leather & Substrate, C
"1" between Leather & Vacuum bag, C
Magnetron power, P/Pmax*100%
100 s
Model
Experim
ent
tHEAT=102 s
h=7 W/K/m2 (natural convection)
𝒑𝒂𝒃𝒔=2.5… 15 MW/m3
kinterlaced yarns= 0.04 W/m/K
Model describes satisfactory the experiment
Note: thermocouples are slow as compared with
„ideal“ temperature in the model
S. Soldatov, Model of microwave assisted thermal adhesion of synthetic leather to a plastic substrate, COMSOL Conference, München, 2016
Institute for Pulsed Power and
Microwave Technology
13 21.10.2016
Optimization of process
To decrease the time of heating (below 60 s), but reach the melting point in glue! (~120 °C)
To reduce the heat load in the coating material (PVC leather damage temperature ~80 °C)
interlaced yarns
PVC dense
PVC foam
Air
Substrate
(ABS-PC)
-1 -0.5 0 0.5 1 1.5 2 2.5 3 3.5
3.5
3.0
2.5
2.0
1.5
1.0
0.5
0 10-3
10-3
2. To increase the heating rate (pabs)
1. To increase the cooling rate (𝑞𝑐𝑜𝑛𝑣)
3. To improve the insulation (k) < 80 °C
110…130 °C
S. Soldatov, Model of microwave assisted thermal adhesion of synthetic leather to a plastic substrate, COMSOL Conference, München, 2016
Institute for Pulsed Power and
Microwave Technology
14 21.10.2016
Leather is
hotter than
Glue!!
ZtHEAT=85 s
h=7 W/K/m2
pglue <5.5 MW/m3
natural air convection
Z
X
Y
Z, m
Substrate
Glu
e
PV
C L
eath
er
Tem
per
atu
re, C
Inte
rlac
ed y
arns
T, CZtHEAT=14 s
h=70 W/K/m2
pglue<23.0 MW/m3
forced air convection
Z
X
Y
T, C
Substrate
Glu
e
PV
C L
eath
er
Z, m
Tem
per
atu
re, C
Inte
rlac
ed y
arn
s
Optimization: absorbed power and surface cooling
reference case optimized
S. Soldatov, Model of microwave assisted thermal adhesion of synthetic leather to a plastic substrate, COMSOL Conference, München, 2016
Institute for Pulsed Power and
Microwave Technology
15 21.10.2016
Optimization: heat conductivity of textile layer
Temperature gradient is more dependent on the absorbed power in glue, pglue.
The heating time is dependent both on k and pglue
0.02 0.03 0.04 0.05 0.06 0.07 0.08
70
80
90
100
110
120
130
Glue
PVC Leather
T, C
a)
0.02 0.03 0.04 0.05 0.06 0.07 0.080
2
4
6
8
10
12
14
16
18
kinterlaced yarns
, W/m/K
b)
Hea
ting t
ime,
s
0.02 0.03 0.04 0.05 0.06 0.07 0.08
70
80
90
100
110
120
130 c)
Glue
PVC Leather
T, C
0.02 0.03 0.04 0.05 0.06 0.07 0.080
2
4
6
8
10
12
14
16
18d)
Hea
ting t
ime,
s
kinterlaced yarns
, W/m/K
pglue< 23 MW/m3
h=70 W/K/m2
The time required for heating 2/3 of
the glue volume above 120 C.
pglue< 30 MW/m3
h=70 W/K/m2
S. Soldatov, Model of microwave assisted thermal adhesion of synthetic leather to a plastic substrate, COMSOL Conference, München, 2016
Institute for Pulsed Power and
Microwave Technology
16 21.10.2016
Coating of a cover of the glove box of Land Rover
S. Soldatov, Model of microwave assisted thermal adhesion of synthetic leather to a plastic substrate, COMSOL Conference, München, 2016
Institute for Pulsed Power and
Microwave Technology
17 21.10.2016
Conclusions
Microwave assisted bonding of PVC artificial leather to the
plastic substrate is possible but requires the optimization of
the process and materials.
Such an optimization is inevitable without numerical
modelling which gives us the understanding how and where
the energy is absorbed, how it is transferred and dissipated in
materials.
Optimization of
absorbed microwave power (loss factor of glue),
heat sink at the leather surface and
fabric layer insulating properties
allow to reach the melting temperature in the hot-melt glue
keeping the coating material below its damage temperature.
S. Soldatov, Model of microwave assisted thermal adhesion of synthetic leather to a plastic substrate, COMSOL Conference, München, 2016
Institute for Pulsed Power and
Microwave Technology
18 21.10.2016 S. Soldatov - Microwave assisted bonding of synthetic leather to plastic substrates, 3GCMEA Cartagena (Spain), 25-29
July 2016
Thank you for your attention!
ACKNOWLEDGMENTS
This research is funded by the Federal Ministry for Economic Affairs and Energy (BMWi) within the funding
action “Zentrale Innovationsprogramm Mittelstand (ZIM)” under funding number KF3158002CJ3.