LOCTITE 431
Harmonization Code : 3907.30.00.40 | Epoxy Mold Compounds containing by weight more than 70 % silicon dioxide
Main features
- Medium-Viscosity Application Control
- Rapid Multi-Material Bonding
- Strong Shear-Oriented Performance
Product Description
LOCTITE 431 is a one-part, medium-viscosity ethyl cyanoacrylate instant adhesive for rapid bonding of metals, plastics, elastomers, and selected porous materials. Its viscosity range of 600 to 1,200 mPa s gives more placement control than very-low-viscosity grades while retaining quick fixture on many substrates. It is used in assemblies where uniform stress distribution and tension or shear performance are important. Fixture time varies with material, from 5 to 10 seconds on polycarbonate to 180 to 300 seconds on steel under the specified conditions. Full chemical and solvent resistance develops after at least 24 hours.
Key features
- Medium-viscosity placement control: A 600 to 1,200 mPa s viscosity supports controlled dispensing while maintaining rapid cure.
- Broad material bonding: The adhesive bonds tested metals, plastics, elastomers, and selected porous materials.
- Strong shear-oriented performance: Documented steel and aluminum lap-shear values support evaluation for tension and shear-loaded joints.
Applications / Suitable for
- Bonding metals, plastics, and elastomers
- Assemblies requiring uniform stress distribution
- Bonding wood, paper, leather, and fabric
TDS, SDS & Technical Documents
Technical Specifications
General Properties
Chemistry Type
Ethyl cyanoacrylate
Color
Transparent, colorless to straw colored liquid
The color
Component System
One component
Describes the number of components that must be supplied, mixed, or activated before application or cure.
Specific Gravity
1.07
Specific gravity (SG) is the ratio of the density of a substance to the density of a reference substance; equivalently, it is the ratio of the mass of a substance to the mass of a reference substance for the same given volume.
For liquids, the reference substance is almost always water (1), while for gases, it is air (1.18) at room temperature. Specific gravity is unitless.
Thermal Properties
Glass Transition Temperature (Tg)
183 °C
The glass transition temperature for organic adhesives is a temperature region where the polymers change from glassy and brittle to soft and rubbery. Increasing the temperature further continues the softening process as the viscosity drops too. Temperatures between the glass transition temperature and below the decomposition point of the adhesive are the best region for bonding.
The glass-transition temperature Tg of a material characterizes the range of temperatures over which this glass transition occurs.
Linear thermal expansion
364x10^-6 K -1
Thermal Conductivity
0.3 W/m.K
Thermal conductivity describes the ability of a material to conduct heat. It is required by power packages in order to dissipate heat and maintain stable electrical performance.
Thermal conductivity units are [W/(m K)] in the SI system and [Btu/(hr ft °F)] in the Imperial system.
Physical Properties
Viscosity
800 to 1,200 mPa.s
Viscosity is a measurement of a fluid’s resistance to flow.
Viscosity is commonly measured in centiPoise (cP). One cP is defined as
the viscosity of water and all other viscosities are derived from this base. MPa is another common unit with a 1:1 conversion to cP.
A product like honey would have a much higher viscosity -around 10,000 cPs-
compared to water. As a result, honey would flow much slower out of a tipped glass than
water would.
The viscosity of a material can be decreased with an increase in temperature in
order to better suit an application
Electrical Properties
Dielectric Strength
25 kV/mm
Dielectric strength is measured in kV per mm and is calculated by the Breakdown voltage divided by the thickness of the tested material.
Those two properties go hand in hand and while Breakdown voltage is always thickness dependent, dielectric strength is a general material property.
As an example, the dielectric strength of Polyimide is 236 kV/mm. If we place 1mm of Polyimide between two electrodes, it will act as an insulator until the voltage between the electrodes reaches 236 kV. At this point it will start acting as a good conductor, causing sparks, potential punctures and current flow.
Surface Resistivity
1.0×10^15 Ohms Ohms/sq
Volume Resistivity
10.9×10^15 Ohms⋅cm
Volume resistivity, also called volume resistance, bulk resistance or bulk resistivity is a thickness dependent measurement of the resistivity of a material perpendicular to the plane of the surface.
Curing Conditions
Fixture Time
180 to 300 seconds
Additional Information
Technical properties
As-supplied / before-processing properties
Typical values for the product before cure, application, or assembly.
| Property | Value | Unit | Method / condition |
|---|---|---|---|
| Appearance | Transparent, colorless to straw liquid | - | Uncured |
| Chemical type | Ethyl cyanoacrylate | - | As supplied |
| Components | One part | - | No mixing required |
| Specific gravity | 1.07 | - | 25 deg C |
| Viscosity | 600 to 1,200 | mPa s | Cone and plate, 25 deg C, shear rate 3,000 s^-1 |
| Viscosity | 800 to 1,200 | mPa s | Brookfield LVF, spindle 2, 6 rpm, 25 deg C |
| Cure mechanism | Humidity | - | Atmospheric moisture |
Technical properties
After-processing / final-state properties
Typical values for the cured or installed product under the listed conditions.
| Property | Value | Unit | Method / condition |
|---|---|---|---|
| Fixture time, polycarbonate | 5 to 10 | s | 22 deg C, 50% RH; time to 0.1 N/mm^2 shear strength |
| Fixture time, aluminum | 10 to 15 | s | 22 deg C, 50% RH; time to 0.1 N/mm^2 shear strength |
| Fixture time, steel | 180 to 300 | s | 22 deg C, 50% RH; time to 0.1 N/mm^2 shear strength |
| Glass transition temperature | 183 | deg C | ISO 11359-2; cured 1 week at 22 deg C |
| Thermal conductivity | 0.3 | W/(m K) | ISO 8302; cured 1 week at 22 deg C |
| Lap shear strength, grit-blasted steel | 25 to 31 | N/mm^2 | Cured 1 week at 22 deg C |
| Dielectric breakdown strength | 25 | kV/mm | IEC 60243-1; cured 1 week at 22 deg C |
