Structural Bonding

Bonding Selector Guide
PERFORMANCE
CONSIDERATIONS
BENEFITS
LIMITATIONS
TEMPERATURE RESISTANCE
ADHESIVE CATEGORY
Cyanoacrylates Epoxies Hot Melts Light Cure Silicones Elastomers Urethanes
Wide range of
bonding applications
Low solvent
resistance
Wide range of
formulations
Mixing required
Versatile,
fast, large
gap filling
Limited heat
resistance
Rapid cure /
adhesion to
plastics
Light cure
system required
Excellent
temperature
resistance
Low adhesion
strength
Flexible,
paintable,
bonder/sealant
High temperature
resistance
Excellent
toughness /
flexibility
Sensitive to
moisture
2-Part
Acrylics
Good impact
resistance /
flexibility
2-Step
Acrylics
Good impact
resistance,
no-mix
Mixing required Primer required
Typical for the category -65°F to +180°F -65°F to +180°F -65°F to +250°F -65°F to +300°F -65°F to +400°F -40°F to +200°F -65F° to +250°F -65°F to +250°F -65°F to +300°F
Highest Rated Product +250°F +400°F +330°F +350°F +725°F +200°F +300°F +250°F +400°F
ENVIRONMENTAL RESISTANCE
Polar Solvents
(ex. H2O, Ethylene Glycol IPA, Acetone)
Non-Polar Solvents
(ex. Motor Oil, Toluene, Gasoline, ATF)
ADHESION TO SUBSTRATES
Poor 1
Very Good Good Good Good Good Good Good Good
Good Excellent Good Very Good Poor to Fair Poor Good Very Good Very Good
Metals Very Good Excellent Good Good Good Very Good Good Excellent Excellent
Plastics 2 Excellent Fair Very Good Excellent Fair Good Very Good Excellent Fair
Glass Poor Excellent Good Excellent Very Good Good Good Good Excellent
Rubber Very Good Fair Fair Fair Good Poor Good Poor Poor
Wood Good Very Good Excellent Poor Fair Very Good Fair Good Good
OVERLAPPING SHEAR
STRENGTH
High High Low High Low Medium Medium High High
PEEL STRENGTH Low 5 Medium Medium Medium Medium Medium Medium High Medium
TENSILE STRENGTH High High Low High Medium Medium Medium High High
ELONGATION / FLEXIBILITY Low Low High Medium High High High Medium Medium
HARDNESS Rigid Rigid Semi-Soft Semi-Rigid Soft Soft Soft Semi-Rigid Semi-Rigid
PROCESS
CONSIDERATIONS
ADHESIVE CATEGORY
Cyanoacrylates Epoxies Hot Melts Light Cure Silicones Elastomers Urethanes
2-Part
Acrylics
NUMBER OF COMPONENTS 1 2 1 1 1 1 2 2 2
CURE TEMPERATURE
Room
Temperature
Room
Temperature
Room
Temperature 3
UV/Visible
Room
Temperature
Room
Temperature
Room
Temperature
Room
Temperature
2-Step
Acrylics
Room
Temperature
FIXTURE TIME
Average 60 seconds 20 minutes 70 seconds 30 seconds 25 minutes 25 minutes 25 minutes 20 minutes 5 minutes
Fastest 5 seconds 3 to 5 minutes 20 seconds 5 seconds 2 minutes 10 minutes 5 minutes 3 to 5 minutes 30 seconds
FULL CURE TIME 24 hours 12 to 24 hours
1 hour
(or when cooled) 4
30 to 60
seconds
1 to 7 days 1 to 7 days 24 hours 24 hours 24 hours
GAP FILL
Ideal (in inches) 0.001 to 0.006 0.004 to 0.006 0.002 to 0.005 0.002 to 0.010 0.001 to 0.006 0.001 to 0.006 0.004 to 0.006 0.010 to 0.040 0.002 to 0.004
Maximum (in inches) 0.010 0.125 0.240 0.25 0.25 0.24 0.125 0.5 0.040
DISPENSING / MIXING
EQUIPMENT REQUIRED
No Yes Yes No No No Yes Yes No
LIGHT CURE VERSIONS
AVAILABLE?
For more information on
Yes Yes No Yes Yes No No No Yes
each adhesive category
refer to pages…
4-7 24-29 8-11 12-15 56-59 16-17 24-29 21, 23 20, 22
1 Cyanoacrylates have very good moisture resistance on plastics.
2 Uncured liquid adhesives may cause stress cracking of certain thermoplastics, e.g., polycarbonate, acrylic, and polysulfone. Special products and
process techniques are available. Consult the Loctite ® Design Guide to Bonding Plastics (LT-2197) or contact 1-800-LOCTITE (562-8483) for more information.
3 Elevated temperatures are required to dispense liquid Hot Melt Adhesives.
4 Urethane Hot Melts require 24 hours for full cure.
5 Exception: Toughened cyanoacrylates have HIGH peel strength.
3
BONDING Selector Guide