CHO-BOND caulks and sealants are electrically
conductive epoxy, silicone and acrylic resins. Their
purpose is to provide effective EMI/EMP shielding and
sealing, filling larger gaps than do adhesives. Caulks
are available as one-component, non-hardening systems
or two-component, curing systems. Some CHO-BOND caulks
have excellent oxide layer bite-thru. They can be dispensed
with conventional caulking guns.
Rigid Epoxies CHO-BOND
two-component epoxy caulks are filled with silver-plated-copper.
They provide excellent adhesion to dissimilar substrates.
These
epoxy systems can be used in lap or butt joint applications,
but should be used only if the seam will not be broken.
CHO-BOND 360-208 epoxy does not require contact pressure
during cure.
Silicones
and Flexible Polyisobutylenes
One-component, non-hardening sealants
are formulated to shield or seal joints and seams likely
to be disassembled or subject to vibration or warping.
A key feature is their capacity to remain adherent without
cracking or pulling away from the surface. These CHO-BOND
sealants are silver-plated-copper-filled silicone or
polyisobutylene filled with silver-plated-glass, silver-plated-copper,
or silver-plated-aluminum. Metallic surfaces may require
priming with CHO-BOND primer to promote better adhesion
of the silicone caulks. CHO-BOND 1038 and CHO-BOND 1075
compounds may be used as fillet seals. All other polyisobutylene
and silicone materials require contact pressure to develop
their electrical properties.
Corrosion-Resistant
Sealants
Chomerics pioneered
silver-plated-aluminum particle technology to
minimize the galvanic corrosion effects of conductive
elastomer gaskets. This highly conductive filler is
also used in our CHO-BOND 1075 sealant. The Ag/Al particle
will provide a more compatible system for aluminum flanges.
Extensive testing conducted at Chomerics
and by the USAF has shown reduced corrosion at joints
while EMI shielding performance is maximized. Standard
specifications have been developed for these Ag/Al filled
silicone sealants. Additional testing includes: corrosion-resistance
to MIL-STD-810 salt fog; long-term effects on both physical
and electrical properties; paintability; lightning survivability;
and NASA outgassing. Technical bulletins for these products
are available on request.
Specifications
and Product Characteristics
(Contact Chomerics for complete specifications and
test procedures)
CHO-BOND Adhesive
360-20
360-208
1035*
1038*
1075***
4660
4669
1086
Binder
epoxy
epoxy
silicone
silicone
silicone
polyiso-butylene
polyiso-butylene
primer
for 1035, 1038
Filler
Ag/Cu
Ag/Cu,
Ag
Ag/glass
Ag/Cu
Ag/Al
Ag/Cu
Ag/CU
Mix
Ratio (by wgt.)
1:1
100:33
1-part
1-part
1-part
1-part
1-part
1-part
Consistency
Medium
paste
very
thick
thin
paste
medium
paste
medium
paste
gritty
paste
gritty
paste
thin
fluid
Specific
Gravity
5.0
± 0.30
4.0
± 0.40
1.9
± 0.10
3.55
± 0.35
2.0
± 0.25
2.0
± 0.30
2.0
± 0.30
0.78
± 0.10
Minimum
Lap Shear Strength, psi (MPa)
1600
(11.04)
1400
(9.66)
100
(0.69)
120
(0.83)
100
(0.69)
N/A
N/A
N/A
Maximum
DC Volume Resistivity, ohm-cm
0.005
0.01
0.05
0.01
0.01
0.08
0.08
N/A
Use
Temperature
-80
to 212°F(-62 to 100° C)
-80
to 212°F(-62 to 100° C)
-67
to 392°F(-55 to 200° C)
-67
to 257°F(-55 to 125° C)
-67
to 392°F(-55 to 200° C)
-67
to 212°F(-55 to 100° C)
-67
to 212°F(-55 to 100° C)
-112
to 392°F(-80 to 200° C)
Elevated
Temperature Cure Cycle
2.0
hrs. @ 150°F (66°C)
0.75
hrs. @ 212°F (100°C)
N/A
N/A
N/A
N/A
N/A
N/A
Room
Temperature Cure Time
24
hrs.
24
hrs.
1
wk.**
1
wk.**
1
wk.**
1
wk.**
1
wk.**
0.5
hr.
Working
Life
1.0
hr.
1.0
hr.
0.5
hr.
0.5
hr.
0.25
hr.
0.5
hr.
2.5
hr.
N/A
Shelf
Life, mos.
9
9
6
6
6
6
6
6
Coverage,
in2/lb. (cm2/g)
500
(7.1)
700
(9.9)
1500
(21.3)
750
(10.6)
1200
(17.0)
900
(12.8)
900
(12.8)
N/A
Recommended
Thickness, in. (cm)
0.010
min. (0.03)
0.010
min. (0.03)
0.007
min. (0.02)
0.007
min. (0.02)
0.010
min. (0.03)
0.015
min. (0.04)
0.015
min. (0.04)
0.0002
max (0.001)
* U.S.
Patent 4,011,360.
** Cure is sufficient for handling in 24 hours. Full specification
properties are developed after 1 week (168 hours.)
*** Values shown for 1075 reflect typical properties.
PRODUCT
NOTES
360-20
Large
particle size allows for thick bond-lines and oxide layer bite-thru.
360-208
Large particle size allows for thick bond-lines and oxide
layer bite-thru. No contact pressure required.
1035
Lowest cost silicone caulk. Bonds well to primed aluminum.
Non-corrosive, room temperature cure system. Not recommended
for vibration or EMP environments.
1038
Maximum EMI performance. Excellent fillet in military
environment. Non-corrosive, room temperature cure system.
No maximum thickness limits.
1075
For bonding Ag/Al conductive elastomers.
4660
Resists acids, alkalis, salts. Attacked by oxidizing agents
and halogens. Best applied before assembly. Remains flexible.
1.5 pound cartridge (0.7 kg)
4 ounce tube (113.4 g)
CHO-BOND 4669
CHO-BOND 466
51-05-4669-0000
51-02-4669-0000
1.5 pound cartridge (0.7 kg)
4 ounce tube (113.4 g)
Primers
CHO-BOND 1086
50-01-1086-0000
1 pint (0.47 L)
Note: Custom packaging can be accommodated. Please inquire.
Every shipment of Chomerics' conductive compounds is accompanied
by a Certificate of Conformance to Chomerics specifications.
Additional test reports can be obtained for a service
charge. Quality control procedures conform to MIL-I-45208.
