LOCTITE 4981
Harmonization Code : 3907.30.00.40 | Epoxy Mold Compounds containing by weight more than 70 % silicon dioxide
Main features
- Heat-Resistant Instant Bonding
- Thermal-Cycling and Humidity Resistance
- Rapid Multi-Substrate Fixturing
Product Description
LOCTITE 4981 combines one-part ethyl cyanoacrylate chemistry with medium-viscosity flow for instant bonding of rubber, plastic and metal assemblies requiring heat resistance. Its colorless to pale-yellow liquid form has a typical viscosity of 400 to 600 mPa s at 25 deg C and cures through atmospheric humidity. The grade resists thermal cycling and humidity, while fixture times under specified conditions range from 2 to 10 seconds on aluminum and 5 to 10 seconds on ABS. Cured steel lap-shear data cover room-temperature and elevated-temperature conditions.
Key features
- Heat-resistant grade: Cured steel lap-shear data include testing at 121 deg C after an elevated-temperature conditioning cycle.
- Rapid fixture response: Fixture time is 2 to 10 seconds on aluminum and 5 to 10 seconds on ABS under specified conditions.
- Environmental resistance: The formulation resists thermal cycling and humidity.
Applications
Bonding rubber, plastic and metal assemblies where heat, thermal-cycling or humidity resistance is required.
TDS, SDS & Technical Documents
Technical Specifications
General Properties
Appearance
Transparent, colorless to pale yellow liquid
Appearance at room temperature.
Chemistry Type
Ethyl cyanoacrylate
Specific Gravity
1.1
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.
Other Properties
Storage Temperature
2 °C to 8 °C
Electrical Properties
Volume Resistivity
10×10¹⁵ 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
400 to 600 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)
120 °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
0.1 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.
Additional Information
Technical properties
As-supplied / before-processing properties
| Property | Value | Unit | Method / condition |
|---|---|---|---|
| Appearance | Transparent, colorless to pale yellow liquid | Uncured; LMS | |
| Specific gravity | 1.1 | Typical; 25 deg C | |
| Viscosity | 400 to 600 | mPa s | Typical; Brookfield LVF; spindle 2; 30 rpm; 25 deg C |
Technical properties
After-processing / final-state properties
| Property | Value | Unit | Method / condition |
|---|---|---|---|
| Coefficient of thermal expansion | 80 x 10^-6 | K^-1 | Typical; ISO 11359-2; after 24 h at 22 deg C |
| Thermal conductivity | 0.1 | W/(m K) | Typical; ISO 8302; after 24 h at 22 deg C |
| Glass transition temperature | 120 | deg C | Typical; ASTM E 228; after 24 h at 22 deg C |
| Dielectric breakdown strength | 25 | kV/mm | Typical; IEC 60243-1; after 24 h at 22 deg C |
| Volume resistivity | 10 x 10^15 | ohm cm | Typical; IEC 60093; after 24 h at 22 deg C |
| Lap shear strength - steel | 19 | N/mm^2 | Typical; ISO 4587; grit-blasted steel; cured 24 h at 22 deg C |
| Lap shear strength at 121 deg C | >=6.9 | N/mm^2 | Typical; ISO 4587; grit-blasted steel; 24 h at 22 deg C plus 24 h at 121 deg C; tested at 121 deg C |
