ABLESTIK 77-2LTC
Harmonization Code : 5906100000 | Adhesive tape of a width not exceeding 20cm
Main features
- One-Component, Solvent-Free Epoxy for Attaching Surface-Mount Devices
- Smooth Non-Tailing Non-Sag Consistency
- 2.5 x 10^14 ohm-cm Volume Resistivity
Product Description
LOCTITE® ABLESTIK 77-2LTC is a one-component, solvent-free epoxy adhesive designed for attaching surface-mount devices to printed circuit boards before wave soldering. The blue, electrically insulating material has a soft, smooth consistency and is formulated to resist tailing and sagging during screening, pin-transfer, or dot-dispensing processes. It provides a typical viscosity of 33,000 mPa·s at 25°C and a three-day work life at 25°C. Guideline heat-cure schedules range from 30 minutes at 80°C to 5 minutes at 150°C.
Key features
- Controlled dispensing: Soft, smooth consistency with no tailing or sagging supports small, uniform adhesive-dot placement.
- Electrically insulating: Typical cured volume resistivity is 2.5 × 1014 ohm-cm.
- Flexible heat-cure options: Guideline schedules include 30 minutes at 80°C, 15 minutes at 100°C, 10 minutes at 125°C, or 5 minutes at 150°C.
Applications / Suitable for
- Attaching surface-mount devices to printed circuit boards before wave soldering
- Capacitor attachment
- Resistor attachment
- Screening, pin-transfer, and dot-dispensing processes
TDS, SDS & Technical Documents
Technical Specifications
General Properties
Appearance
Blue
Appearance at room temperature.
Chemistry Type
Epoxy
Work life @25°C
72 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.
Thermal Properties
Glass Transition Temperature (Tg)
80 °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.
Thermal Conductivity
0.5 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.
Weight Loss @ 300°C
0.24 %
Electrical Properties
Volume Resistivity
2.5×10¹⁴ 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.
Physical Properties
Viscosity
33000 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
Additional Information
Technical properties
As-supplied / before-processing properties
Typical properties, work-life information, storage conditions, and guideline cure schedules before final processing.
| Property | Value | Unit | Method / condition |
|---|---|---|---|
| Technology | Epoxy | — | One-component adhesive |
| Appearance | Blue liquid paste | — | TDS appearance and SDS physical-state description |
| Viscosity | 33,000 | mPa·s (cP) | At 25°C; method not stated |
| Specific gravity | 1.5 | — | SDS physical-property value |
| Work life | 3 | days | At 25°C |
| Shelf life | 365 | days | At -40°C |
| Shelf life | 3 | days | At 25°C |
| Recommended cure schedule | 30 | minutes | At 80°C; guideline recommendation |
| Alternative cure schedules | 15, 10, or 5 | minutes | 15 minutes at 100°C, 10 minutes at 125°C, or 5 minutes at 150°C; guideline recommendations |
| Optimal storage | -40 | °C | Store unopened in a dry location; do not refreeze after thawing to 25°C |
Technical properties
After-processing / final-state properties
Typical physical, thermal, ionic, electrical, and bonded-joint properties of the cured adhesive. Values are reference data and are not product specifications.
| Property | Value | Unit | Method / condition |
|---|---|---|---|
| Glass-transition temperature | 80 | °C | Method and cure condition not stated |
| Coefficient of thermal expansion — below Tg | 44 | ppm/°C | TMA; cure condition not stated |
| Coefficient of thermal expansion — above Tg | 86 | ppm/°C | TMA; cure condition not stated |
| Hardness | 90 | Shore D | Cure condition and test method not stated |
| Weight loss at 300°C | 0.24 | % | Test method, exposure duration, and cure condition not stated |
| Thermal conductivity | 0.5 | W/(m·K) | At 121°C; method, specimen geometry, and cure condition not stated |
| Extractable chloride | 30 | ppm | Test method and extraction conditions not stated |
| Extractable sodium | 5 | ppm | Test method and extraction conditions not stated |
| Extractable potassium | 5 | ppm | Test method and extraction conditions not stated |
| Volume resistivity | 2.5 × 1014 | ohm-cm | Test method and cure condition not stated |
| Dielectric constant | 4.2 | — | At 1 kHz |
| Dissipation factor | 0.0078 | — | At 1 kHz |
| Device shear strength — ceramic capacitors | 1,000 | grams | Device dimensions, test method, cure condition, and test temperature not stated |
| Device shear strength — SOTs | 2,000 | grams | Device dimensions, test method, cure condition, and test temperature not stated |
| Device shear strength — thick-film resistors | 3,000 | grams | Device dimensions, test method, cure condition, and test temperature not stated |
| Lap shear strength — aluminum to aluminum | 15 (2,300) | N/mm² (psi) | Tested at 25°C; surface preparation, bondline, cure condition, and test method not stated |
