ABLESTIK 642-1
Harmonization Code : 3910.00.00.90 | Silicones in Primary Forms; Others
Main features
- Extended 8-Hour Assembly Window
- Multiple Heat-Cure Schedules
- Low-Outgassing Assembly Bonding
Product Description
LOCTITE ABLESTIK 642-1 is a one-part, transparent, unfilled epoxy adhesive for general assembly bonding. It combines an 8-hour work life at 25 deg C with elevated-temperature cure options of 2 hours at 75 deg C, 1 hour at 95 deg C, or 30 minutes at 120 deg C. The cured adhesive has a typical Shore D hardness of 87 and aluminum-to-aluminum lap shear strength of 19.3 N/mm^2 at 25 deg C. The formulation passes NASA outgassing standards, making it relevant to assemblies that require controlled outgassing alongside heat-cure processing.
Key features
- Extended assembly window: An 8-hour work life at 25 deg C provides time for adhesive application and part positioning.
- Multiple elevated-temperature cures: Three cure schedules allow selection between lower-temperature processing and a faster 30-minute cycle.
- Low-outgassing performance: The formulation passes NASA outgassing standards for assemblies that require controlled outgassing.
Applications
Applications include general assembly bonding and heat-cured assemblies that require low-outgassing performance.
TDS, SDS & Technical Documents
Technical Specifications
General Properties
Appearance
Transparent liquid
Appearance at room temperature.
Component System
One-component
Describes the number of components that must be supplied, mixed, or activated before application or cure.
Work life @25°C
8 hours
Work life is the amount of time we have to work with a material until it is no longer able to be easily worked and applied on a substrate.
It is based on the change in viscosity and it can rely on the application requirements.
Physical Properties
Thixotropic index
1.0
Thixotropic Index is a ratio of a material s viscosity at two different speeds in Ambient temperature, generally different by a factor of ten.
A thixotropic material s viscosity will decrease as agitation or pressure is increased. It indicates the capability of a material to hold its shape. Mayonnaise is a great example of this. It holds its shape very well, but when a shear stress is applied, the material easily spreads.
It helps in choosing a material in accordance to the application, dispense method and viscosity of a material.
Viscosity
5,500 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
Thermal Properties
Glass Transition Temperature (Tg)
137.0 °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.
Electrical Properties
Volume Resistivity
6.50×10¹⁴ 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.
Additional Information
Technical properties
As-supplied / before-processing properties
Technical values are typical; the listed cure schedules are guideline recommendations.
| Property | Value | Unit | Method / condition |
|---|---|---|---|
| Appearance | Transparent liquid | As supplied | |
| Viscosity | 5,500 | mPa s | 25 deg C |
| Thixotropic index | 1.0 | Typical | |
| Work life | 8 | hours | 25 deg C |
| Shelf life, pre-mixed frozen | 365 | days | -40 deg C |
| Shelf life, kits | 365 | days | 25 deg C |
| Cure schedule | 2 at 75; 1 at 95; 0.5 at 120 | hours at deg C | Guideline heat-cure options |
Technical properties
After-processing / final-state properties
Values are typical for cured LOCTITE ABLESTIK 642-1 under the stated conditions.
| Property | Value | Unit | Method / condition |
|---|---|---|---|
| Shore D hardness | 87 | Typical cured material | |
| Glass transition temperature | 137.0 | deg C | Typical cured material |
| Coefficient of thermal expansion | 84 | ppm/deg C | Typical cured material |
| Volume resistivity | 6.50 x 10^14 | ohm cm | 100 deg C |
| Dielectric constant | 3.36 | 1 kHz | |
| Dissipation factor | 0.007 | 1 kHz | |
| Lap shear strength | 19.3 | N/mm^2 | Aluminum-to-aluminum; 25 deg C |
