User Manual

Technical Data Sheet
LOCTITE
®
420™
January-2010
PRODUCT DESCRIPTION
LOCTITE
®
420™ provides the following product
characteristics:
Technology Cyanoacrylate
Chemical Type Ethyl cyanoacrylate
Appearance (uncured) Transparent, colorless to straw
colored liquid
LMS
Components One part - requires no mixing
Viscosity Very low
Cure Humidity
Application Bonding
Key Substrates Plastics, Rubbers and Metals
LOCTITE
®
420™ is a general purpose cyanoacrylate instant
adhesive.
Mil-A-46050C
LOCTITE
®
420™ is tested to the lot requirements of Military
Specification Mil-A-46050C. Note: This is a regional approval.
Please contact your local Technical Service Center for more
information and clarification.
Commercial Item Description A-A-3097:
LOCTITE
®
420™ has been qualified to Commercial Item
Description A-A-3097. Note: This is a regional approval.
Please contact your local Technical Service Center for more
information and clarification.
TYPICAL PROPERTIES OF UNCURED MATERIAL
Specific Gravity @ 25 °C 1.05
Viscosity, Cone & Plate, mPa·s (cP):
Temperature: 25 °C, Shear Rate: 3,000 s
-1
1 to 4
LMS
Viscosity, Brookfield - LVF, 25 °C, mPa·s (cP):
Spindle 1, speed 60 rpm 1 to 5
Vapour Pressure, hPa <1
Flash Point - See MSDS
TYPICAL CURING PERFORMANCE
Under normal conditions, the atmospheric moisture initiates the
curing process. Although full functional strength is developed
in a relatively short time, curing continues for at least 24 hours
before full chemical/solvent resistance is developed.
Cure Speed vs. Substrate
The rate of cure will depend on the substrate used. The table
below shows the fixture time achieved on different materials
at 22 °C / 50 % relative humidity. This is defined as the time to
develop a shear strength of 0.1 N/mm².
Fixture Time, seconds:
Mild Steel (degreased) 10 to 30
Aluminum (degreased) 5 to 15
Zinc dichromate 30 to 90
Neoprene <5
Rubber, nitrile <5
ABS 10 to 30
PVC 3 to 10
Polycarbonate 20 to 60
Phenolic 5 to 20
Cure Speed vs. Bond Gap
The rate of cure will depend on the bondline gap. Thin bond
lines result in high cure speeds, increasing the bond gap will
decrease the rate of cure.
Cure Speed vs. Humidity
The rate of cure will depend on the ambient relative humidity.
The following graph shows the tensile strength developed with
time on Buna N rubber at different levels of humidity.
% Full Cured Strength @ 22 °C
Cure Time, seconds
100
75
50
25
0
0 10 20 30 40 50 60
60% RH
40% RH
20% RH
Cure Speed vs. Activator
Where cure speed is unacceptably long due to large gaps,
applying activator to the surface will improve cure speed.
However, this can reduce ultimate strength of the bond and
therefore testing is recommended to confirm effect.
Documentation Provided By HMC Electronics
33 Springdale Ave. Canton, MA 02021
http://www.hmcelectronics.com
[phone]